Science.gov

Sample records for flow distribution test

  1. Uninstrumented assembly airflow testing in the Annular Flow Distribution facility

    SciTech Connect

    Kielpinski, A.L.

    1992-02-01

    During the Emergency Cooling System phase of a postulated large-break loss of coolant accident (ECS-LOCA), air enters the primary loop and is pumped down the reactor assemblies. One of the experiments performed to support the analysis of this accident was the Annular Flow Distribution (AFD) experiment, conducted in a facility built for this purpose at Babcock and Wilcox Alliance Research Center in Alliance, Ohio. As part of this experiment, a large body of airflow data were acquired in a prototypical mockup of the Mark 22 reactor assembly. This assembly was known as the AFD (or the I-AFD here) reference assembly. The I-AFD assembly was fully prototypical, having been manufactured in SRS`s production fabrication facility. Similar Mark 22 mockup assemblies were tested in several test facilities in the SRS Heat Transfer Laboratory (HTL). Discrepancies were found. The present report documents further work done to address the discrepancy in airflow measurements between the AFD facility and HTL facilities. The primary purpose of this report is to disseminate the data from the U-AFD test, and to compare these test results to the I-AFD data and the U-AT data. A summary table of the test data and the B&W data transmittal letter are included as an attachment to this report. The full data transmittal volume from B&W (including time plots of the various instruments) is included as an appendix to this report. These data are further analyzed by comparing them to two other HTL tests, namely, SPRIHTE 1 and the Single Assembly Test Stand (SATS).

  2. Field Test of a DHW Distribution System: Temperature and Flow Analyses (Presentation)

    SciTech Connect

    Barley, C. D.; Hendron, B.; Magnusson, L.

    2010-05-13

    This presentation discusses a field test of a DHW distribution system in an occupied townhome. It includes measured fixture flows and temperatures, a tested recirculation system, evaluated disaggregation of flow by measured temperatures, Aquacraft Trace Wizard analysis, and comparison.

  3. Interpreting Variations in Groundwater Flows from Repeated Distributed Thermal Perturbation Tests.

    PubMed

    Hausner, Mark B; Kryder, Levi; Klenke, John; Reinke, Richard; Tyler, Scott W

    2016-07-01

    To better understand the groundwater resources of southern Nye County, Nevada, a multipart distributed thermal perturbation sensing (DTPS) test was performed on a complex of three wells. These wells penetrate an alluvial aquifer that drains the Nevada National Security Site, and characterizing the hydraulic properties and flow paths of the regional groundwater flow system has proven very difficult. The well complex comprised one pumping well and two observation wells, both located 18 m from the pumping well. Using fiber-optic cables and line heaters, DTPS tests were performed under both stressed and unstressed conditions. Each test injects heat into the water column over a period of one to two days, and observes the rising temperature during heat injection and falling temperatures after heating ceases. Aquifer thermal properties are inferred from temperature patterns in the cased section of the wells, and fluxes through the 30-m screened section are estimated based on a model that incorporates conductive and advective heat fluxes. Vertical variations in flux are examined on a scale of tens of cm. The actively flowing zones of the aquifer change between the stressed and unstressed test, and anisotropy in the aquifer permeability is apparent from the changing fluxes between tests. The fluxes inferred from the DTPS tests are compared to solute tracer tests previously performed on the same site. The DTPS-based fluxes are consistent with the fastest solute transport observed in the tracer test, but appear to overestimate the mean flux through the system. PMID:26714003

  4. Development, testing and application of DrainFlow: A fully distributed integrated surface-subsurface flow model for drainage study

    NASA Astrophysics Data System (ADS)

    Shokri, Ali; Bardsley, William Earl

    2016-06-01

    Hydrological and hydrogeological investigation of drained land is a complex and integrated procedure. The scale of drainage studies may vary from a high-resolution small scale project through to comprehensive catchment or regional scale investigations. This wide range of scales and integrated system behaviour poses a significant challenge for the development of suitable drainage models. Toward meeting these requirements, a fully distributed coupled surface-subsurface flow model titled DrainFlow has been developed and is described. DrainFlow includes both the diffusive wave equation for surface flow components (overland flow, open drain, tile drain) and Richard's equation for saturated/unsaturated zones. To overcome the non-linearity problem created from switching between wet and dry boundaries, a smooth transitioning technique is introduced to buffer the model at tile drains and at interfaces between surface and subsurface flow boundaries. This gives a continuous transition between Dirichlet and Neumann boundary conditions. DrainFlow is tested against five well-known integrated surface-subsurface flow benchmarks. DrainFlow as applied to some synthetic drainage study examples is quite flexible for changing all or part of the model dimensions as required by problem complexity, problem scale, and data availability. This flexibility enables DrainFlow to be modified to allow for changes in both scale and boundary conditions, as often encountered in real-world drainage studies. Compared to existing drainage models, DrainFlow has the advantage of estimating actual infiltration directly from the partial differential form of Richard's equation rather than through analytical or empirical infiltration approaches like the Green and Ampt equation.

  5. The distributed-order fractional diffusion-wave equation of groundwater flow: Theory and application to pumping and slug tests

    NASA Astrophysics Data System (ADS)

    Su, Ninghu; Nelson, Paul N.; Connor, Sarah

    2015-10-01

    We present a distributed-order fractional diffusion-wave equation (dofDWE) to describe radial groundwater flow to or from a well, and three sets of solutions of the dofDWE for flow from a well for aquifer tests: one for pumping tests, and two for slug tests. The dofDWE is featured by two temporal orders of fractional derivatives, β1 and β2, which characterise small and large pores, respectively. By fitting the approximate solutions of the dofDWE to data from slug tests in the field, we determined the effective saturated hydraulic conductivity, Ke, transmissivity, Tf, and the order of fractional derivatives, β2 in one test and β2 and β1 in the second test. We found that the patterns of groundwater flow from a well during the slug tests at this site belong to the class of sub-diffusion with β2 < 1 and β1 < 1 using both the short-time and large-time solutions. We introduce the concept of the critical time to link Ke as a function of β2 and β1. The importance of the orders of fractional derivatives is obvious in the approximate solutions: for short time slug tests only the parameter β2 for flow in large pores is present while for long time slug tests the parameters β2 and β1 are present indicating both large and small pores are functioning.

  6. Nonuniform steam generator U-tube flow distribution during natural circulation tests in ROSA-IV large scale test facility

    SciTech Connect

    Kukita, Y.; Nakamura, H.; Tasaka, K. ); Chauliac, C. )

    1988-08-01

    Natural circulation experiments were conducted in a large-scale (1/48 scale in volume) full-height simulator of a Westinghouse-type pressurized water reactor. This facility has two steam generators each containing 141 full-size U-tubes of 9 different heights. Transition of the natural circulation mode was observed in the experiments as the primary of side mass inventory was decreased. Three major circulation modes were observed: single-phase liquid natural circulation, two-phase natural circulation, and reflux condensation. For all these circulation modes, and during the transitions between the modes, the mass flow distribution among the steam generator U-tubes was significantly nonuniform. The longer U-tubes indicated reversed flow at higher primary side mass inventories and also tended to empty earlier than the shorter U-tubes when the primary side mass inventory was decreased.

  7. Pressure distributions from subsonic tests of an advanced laminar-flow-control wing with leading- and trailing-edge flaps

    NASA Technical Reports Server (NTRS)

    Applin, Zachary T.; Gentry, Garl L., Jr.

    1988-01-01

    An unswept, semispan wing model equipped with full-span leading- and trailing-edge flaps was tested in the Langley 14- by 22-Foot Subsonic Tunnel to determine the effect of high-lift components on the aerodynamics of an advanced laminar-flow-control (LFC) airfoil section. Chordwise pressure distributions near the midsemispan were measured for four configurations: cruise, trailing-edge flap only, and trailing-edge flap with a leading-edge Krueger flap of either 0.10 or 0.12 chord. Part 1 of this report (under separate cover) presents a representative sample of the plotted pressure distribution data for each configuration tested. Part 2 presents the entire set of plotted and tabulated pressure distribution data. The data are presented without analysis.

  8. Standardized performance tests of collectors of solar thermal energy: An evacuated flatplate copper collector with a serpentine flow distribution

    NASA Technical Reports Server (NTRS)

    Johnson, S. M.

    1976-01-01

    Basic test results are given for a flat plate solar collector whose performance was determined in the NASA-Lewis solar simulator. The collector was tested over ranges of inlet temperatures, fluxes and one coolant flow rate. Collector efficiency is correlated in terms of inlet temperature and flux level.

  9. Airflow Model Testing to Determine the Distribution of Hot Gas Flow and O/F Ratio Across the Space Shuttle Main Engine Main Injector Assembly

    NASA Technical Reports Server (NTRS)

    Mahorter, L.; Chik, J.; McDaniels, D.; Dill, C.

    1990-01-01

    Engine 0209, the certification engine for the new Phase 2+ Hot Gas Manifold (HGM), showed severe deterioration of the Main Combustion Chamber (MCC) liner during hot fire tests. One theory on the cause of the damage held that uneven local distribution of the fuel rich hot gas flow through the main injector assembly was producing regions of high oxidizer/fuel (O/F) ratio near the wall of the MCC liner. Airflow testing was proposed to measure the local hot gas flow rates through individual injector elements. The airflow tests were conducted using full scale, geometrically correct models of both the current Phase 2 and the new Phase 2+ HGMs. Different main injector flow shield configurations were tested for each HGM to ascertain their effect on the pressure levels and distribution of hot gas flow. Instrumentation located on the primary faceplate of the main injector measured hot gas flow through selected injector elements. These data were combined with information from the current space shuttle main engine (SSME) power balances to produce maps of pressure, hot gas flow rate, and O/F ratio near the main injector primary plate. The O/F distributions were compared for the different injector and HGM configurations.

  10. Flow-Meter and Passive Diffusion Bag Tests and Potential Influences on the Vertical Distribution of Contaminants in Wells at Galena Airport, Galena, Alaska, August to October 2002

    USGS Publications Warehouse

    Vroblesky, Don A.; Peterson, J.E.

    2004-01-01

    Past activities at Galena Airport, a U.S. Air Force Base in Galena, Alaska, have resulted in ground-water contamination by volatile organic compounds. The primary contaminants are petroleum hydrocarbons and chlorinated aliphatic hydrocarbons. The U.S. Geological Survey and Earth Tech, in cooperation with the Air Force Center for Environmental Excellence, conducted investigations at Galena Airport from August to October 2002 using polyethylene diffusion bag samplers and borehole flow-meter testing to examine the vertical distribution of ground-water contamination in selected wells. This investigation was limited to the vicinity of building 1845 and to the area between building 1845 and the Yukon River. In addition, the U.S. Geological Survey was asked to determine whether additional wells are needed to more clearly define the nature and extent of the ground-water contamination at the Air Force Base. Little or no vertical water movement occurred under ambient conditions in the wells tested at Galena Airport, Alaska, in August 2002. All of the ambient vertical flows detected in wells were at rates less than the quantitative limit of the borehole flow meter (0.03 gallons per minute). In wells 06-MW-07 and 10-MW-01, no vertical flow was detected. In wells where ambient flow was detected, the direction of flow was downward. In general, concentrations of volatile organic compounds detected in the low-flow samples from wells at Galena Airport were approximately the same concentrations detected in the closest polyethylene diffusion bag sample for a wide variety of volatile organic compounds. The data indicate that the polyethylene diffusion bag sample results are consistent with the low-flow sample results. Vertical profiling of selected wells using polyethylene diffusion bag samplers at Galena Airport showed that from September 30 to October 1, 2002, little vertical change occurred in volatile organic compound concentrations along the screen length despite the fact that

  11. Fluorescent Particles For Flow Testing

    NASA Technical Reports Server (NTRS)

    Bonnell, Jeremy L.; Stern, Susan M.; Torkelson, Jan R.

    1995-01-01

    Small alumina spheres coated with fluorescent dye used in flow testing of transparent plastic model of check valve. Entrained fluroescent particles make flows visible. After completion of flow test, particles remaining in valve easily detectable and removed for measurement of their sizes.

  12. Testing the frozen flow approximation

    NASA Technical Reports Server (NTRS)

    Lucchin, Francesco; Matarrese, Sabino; Melott, Adrian L.; Moscardini, Lauro

    1993-01-01

    We investigate the accuracy of the frozen-flow approximation (FFA), recently proposed by Matarrese, et al. (1992), for following the nonlinear evolution of cosmological density fluctuations under gravitational instability. We compare a number of statistics between results of the FFA and n-body simulations, including those used by Melott, Pellman & Shandarin (1993) to test the Zel'dovich approximation. The FFA performs reasonably well in a statistical sense, e.g. in reproducing the counts-in-cell distribution, at small scales, but it does poorly in the crosscorrelation with n-body which means it is generally not moving mass to the right place, especially in models with high small-scale power.

  13. Standardized performance tests of collectors of solar thermal energy-a flat-plate collector with a single-tube serpentine flow distribution

    NASA Technical Reports Server (NTRS)

    Johnson, S.

    1976-01-01

    This preliminary data report gives basic test results of a flat-plate solar collector whose performance was determined in the NASA-Lewis solar simulator. The collector was tested over ranges of inlet temperatures, fluxes and coolant flow rates. Collector efficienty is correlated in terms of inlet temperature and flux level.

  14. Infiltration Flow Path Distributions in Unsaturated Rocks

    NASA Astrophysics Data System (ADS)

    Tokunaga, T. K.; Olson, K. R.; Wan, J.

    2004-12-01

    Spatial distributions of infiltration flow paths through rock formations are complex networks that determine flow velocities, control rates of natural geochemical reactions in the subsurface, as well as rates of contaminant transport to underlying groundwater. Despite these important consequences, distributions of infiltration paths and locally fast seepage rates through rocks are not well understood. Laboratory-based studies on fractured rocks cannot easily be conducted on systems large enough to include sufficient fracture network complexity, so that inferences of field-scale flux distributions cannot be reliably made. Field-based studies to date have permitted quantification of only a small fraction of the flow distribution, typically while imposing extremely high fluxes, and therefore have not allowed comprehensive delineation of flow distributions expected under natural recharge. Based on hydraulic scaling considerations, we hypothesize that unsaturated flow path distributions in rock deposits will be similar to those occurring in fractured rock formations under low overall infiltration rates. Talus rock deposits and mine waste rock piles control flow and transport into their respective underlying groundwaters. All of these reasons motivated infiltration experiments in rock packs. Experiments have been conducted on 4 different rock types and system scales ranging from 1 to 46 rock layers. Our experiments showed that infiltration through rocks conforms to no previously reported behavior in soils, and that flow paths do not progressively converge into fewer and fewer flow paths. Instead, a fundamentally different hydraulic structure develops, having an exponential (geometric) flux distribution, with the characteristic scale determined by the characteristic rock size. Although the phenomena are very different, the evolution of flow path distributions and local seepage rate distributions is predictable based on a statistical mechanical model for energy

  15. Effects of flow separation and cove leakage on pressure and heat-transfer distributions along a wing-cove-elevon configuration at Mach 6.9. [Langley 8-ft high temperature tunnel test

    NASA Technical Reports Server (NTRS)

    Deveikis, W. D.

    1983-01-01

    External and internal pressure and cold-wall heating-rate distributions were obtained in hypersonic flow on a full-scale heat-sink representation of the space shuttle orbiter wing-elevon-cove configuration in an effort to define effects of flow separation on cove aerothermal environment as a function of cove seal leak area, ramp angle, and free-stream unit Reynolds number. Average free-stream Mach number from all tests was 6.9; average total temperature from all tests was 3360 R; free-stream dynamic pressure ranged from about 2 to 9 psi; and wing angle of attack was 5 deg (flow compression). For transitional and turbulent flow separation, increasing cove leakage progressively increased heating rates in the cove. When ingested mass flow was sufficient to force large reductions in extent of separation, increasing cove leakage reduced heating rates in the cove to those for laminar attached flow. Cove heating-rate distributions calculated with a method that assumed laminar developing channel flow agreed with experimentally obtained distributions within root-mean-square differences that varied between 11 and 36 percent where cove walls were parallel for leak areas of 50 and 100 percent.

  16. Cold Flow Verification Test Facility

    SciTech Connect

    Shamsi, A.; Shadle, L.J.

    1996-12-31

    The cold flow verification test facility consists of a 15-foot high, 3-foot diameter, domed vessel made of clear acrylic in two flanged sections. The unit can operate up to pressures of 14 psig. The internals include a 10-foot high jetting fluidized bed, a cylindrical baffle that hangs from the dome, and a rotating grate for control of continuous solids removal. The fluid bed is continuously fed solids (20 to 150 lb/hr) through a central nozzle made up of concentric pipes. It can either be configured as a half or full cylinder of various dimensions. The fluid bed has flow loops for separate air flow control for conveying solids (inner jet, 500 to 100000 scfh) , make-up into the jet (outer jet, 500 to 8000 scfh), spargers in the solids removal annulus (100 to 2000 scfh), and 6 air jets (20 to 200 scfh) on the sloping conical grid. Additional air (500 to 10000 scfh) can be added to the top of the dome and under the rotating grate. The outer vessel, the hanging cylindrical baffles or skirt, and the rotating grate can be used to study issues concerning moving bed reactors. There is ample allowance for access and instrumentation in the outer shell. Furthermore, this facility is available for future Cooperative Research and Development Program Manager Agreements (CRADA) to study issues and problems associated with fluid- and fixed-bed reactors. The design allows testing of different dimensions and geometries.

  17. Modeling depth distributions of overland flows

    NASA Astrophysics Data System (ADS)

    Smith, Mark W.; Cox, Nicholas J.; Bracken, Louise J.

    2011-02-01

    Hydrological and erosion models use water depth to estimate routing velocity and resultant erosion at each spatial element. Yet the shear stress distribution imposed on the soil surface and any resulting flow detachment and rill incision is controlled by the full probability distribution of depths of overland flow. Terrestrial Laser Scanning (TLS) is used in conjunction with simple field-flume experiments to provide high-resolution measures of overland flow depth-distributions for three semi-arid hillslope transects with differing soil properties. A two-parameter gamma distribution is proposed as the optimum model for depths of both interrill and rill flows. The shape and scale parameters are shown to vary consistently with distance downslope reflecting the morphological signature of runoff processes. The scale parameter is related to the general increase of depths with discharge ( P < 0.0001) as flows gradually concentrate; the shape parameter is more related to the soil surface roughness and potentially provides a control on the rate of depth, but also velocity increase with discharge. Such interactions between surface roughness and overland flows are of crucial importance for flow hydraulics and modeling sediment transport.

  18. Wing Leading Edge Joint Laminar Flow Tests

    NASA Technical Reports Server (NTRS)

    Drake, Aaron; Westphal, Russell V.; Zuniga, Fanny A.; Kennelly, Robert A., Jr.; Koga, Dennis J.

    1996-01-01

    An F-104G aircraft at NASA's Dryden Flight Research Center has been equipped with a specially designed and instrumented test fixture to simulate surface imperfections of the type likely to be present near the leading edge on the wings of some laminar flow aircraft. The simulated imperfections consisted of five combinations of spanwise steps and gaps of various sizes. The unswept fixture yielded a pressure distribution similar to that of some laminar flow airfoils. The experiment was conducted at cruise conditions typical for business-jets and light transports: Mach numbers were in the range 0.5-0.8, and unit Reynolds numbers were 1.5-2.5 million per foot. Skin friction measurements indicated that laminar flow was often maintained for some distance downstream of the surface imperfections. Further work is needed to more precisely define transition location and to extend the experiments to swept-wing conditions and a broader range of imperfection geometries.

  19. Probability Distribution for Flowing Interval Spacing

    SciTech Connect

    S. Kuzio

    2004-09-22

    Fracture spacing is a key hydrologic parameter in analyses of matrix diffusion. Although the individual fractures that transmit flow in the saturated zone (SZ) cannot be identified directly, it is possible to determine the fractured zones that transmit flow from flow meter survey observations. The fractured zones that transmit flow as identified through borehole flow meter surveys have been defined in this report as flowing intervals. The flowing interval spacing is measured between the midpoints of each flowing interval. The determination of flowing interval spacing is important because the flowing interval spacing parameter is a key hydrologic parameter in SZ transport modeling, which impacts the extent of matrix diffusion in the SZ volcanic matrix. The output of this report is input to the ''Saturated Zone Flow and Transport Model Abstraction'' (BSC 2004 [DIRS 170042]). Specifically, the analysis of data and development of a data distribution reported herein is used to develop the uncertainty distribution for the flowing interval spacing parameter for the SZ transport abstraction model. Figure 1-1 shows the relationship of this report to other model reports that also pertain to flow and transport in the SZ. Figure 1-1 also shows the flow of key information among the SZ reports. It should be noted that Figure 1-1 does not contain a complete representation of the data and parameter inputs and outputs of all SZ reports, nor does it show inputs external to this suite of SZ reports. Use of the developed flowing interval spacing probability distribution is subject to the limitations of the assumptions discussed in Sections 5 and 6 of this analysis report. The number of fractures in a flowing interval is not known. Therefore, the flowing intervals are assumed to be composed of one flowing zone in the transport simulations. This analysis may overestimate the flowing interval spacing because the number of fractures that contribute to a flowing interval cannot be

  20. Blood flow distribution in cerebral arteries

    PubMed Central

    Zarrinkoob, Laleh; Ambarki, Khalid; Wåhlin, Anders; Birgander, Richard; Eklund, Anders; Malm, Jan

    2015-01-01

    High-resolution phase–contrast magnetic resonance imaging can now assess flow in proximal and distal cerebral arteries. The aim of this study was to describe how total cerebral blood flow (tCBF) is distributed into the vascular tree with regard to age, sex and anatomic variations. Forty-nine healthy young (mean 25 years) and 45 elderly (mean 71 years) individuals were included. Blood flow rate (BFR) in 21 intra- and extracerebral arteries was measured. Total cerebral blood flow was defined as BFR in the internal carotid plus vertebral arteries and mean cerebral perfusion as tCBF/brain volume. Carotid/vertebral distribution was 72%/28% and was not related to age, sex, or brain volume. Total cerebral blood flow (717±123 mL/min) was distributed to each side as follows: middle cerebral artery (MCA), 21% distal MCA, 6% anterior cerebral artery (ACA), 12%, distal ACA, 4% ophthalmic artery, 2% posterior cerebral artery (PCA), 8% and 20% to basilar artery. Deviating distributions were observed in subjects with ‘fetal' PCA. Blood flow rate in cerebral arteries decreased with increasing age (P<0.05) but not in extracerebral arteries. Mean cerebral perfusion was higher in women (women: 61±8; men: 55±6 mL/min/100 mL, P<0.001). The study describes a new method to outline the flow profile of the cerebral vascular tree, including reference values, and should be used for grading the collateral flow system. PMID:25564234

  1. Statistical Distribution of Inflation on Lava Flows: Analysis of Flow Surfaces on Earth and Mars

    NASA Technical Reports Server (NTRS)

    Glazel, L. S.; Anderson, S. W.; Stofan, E. R.; Baloga, S.

    2003-01-01

    -dominated terrestrial flows can be identified. Since tumuli form by the injection of lava beneath a crust, the distribution of tumuli on a flow should represent the distribution of thermally preferred pathways beneath the surface of the crust. That distribution of thermally preferred pathways may be a function of the evolution of a basaltic lava flow. As a longer-lived flow evolves, initially broad thermally preferred pathways would evolve to narrower, more well-defined tube-like pathways. The final flow morphology clearly preserves the growth of the flow over time, with inflation features indicating pathways that were not necessarily contemporaneously active. Here, we test using statistical analysis whether this final flow morphology produces distinct distributions that can be used to readily determine the distribution of thermally preferred pathways beneath the surface of the crust.

  2. Estimation of steady-state and transcient power distributions for the RELAP analyses of the 1963 loss-of-flow and loss-of-pressure tests at BR2.

    SciTech Connect

    Dionne, B.; Tzanos, C. P.

    2011-05-23

    To support the safety analyses required for the conversion of the Belgian Reactor 2 (BR2) from highly-enriched uranium (HEU) to low-enriched uranium (LEU) fuel, the simulation of a number of loss-of-flow tests, with or without loss of pressure, has been undertaken. These tests were performed at BR2 in 1963 and used instrumented fuel assemblies (FAs) with thermocouples (TC) imbedded in the cladding as well as probes to measure the FAs power on the basis of their coolant temperature rise. The availability of experimental data for these tests offers an opportunity to better establish the credibility of the RELAP5-3D model and methodology used in the conversion analysis. In order to support the HEU to LEU conversion safety analyses of the BR2 reactor, RELAP simulations of a number of loss-of-flow/loss-of-pressure tests have been undertaken. Preliminary analyses showed that the conservative power distributions used historically in the BR2 RELAP model resulted in a significant overestimation of the peak cladding temperature during the transient. Therefore, it was concluded that better estimates of the steady-state and decay power distributions were needed to accurately predict the cladding temperatures measured during the tests and establish the credibility of the RELAP model and methodology. The new approach ('best estimate' methodology) uses the MCNP5, ORIGEN-2 and BERYL codes to obtain steady-state and decay power distributions for the BR2 core during the tests A/400/1, C/600/3 and F/400/1. This methodology can be easily extended to simulate any BR2 core configuration. Comparisons with measured peak cladding temperatures showed a much better agreement when power distributions obtained with the new methodology are used.

  3. Resource Prospector Propulsion Cold Flow Test

    NASA Technical Reports Server (NTRS)

    Williams, Hunter; Pederson, Kevin; Dervan, Melanie; Holt, Kimberly; Jernigan, Frankie; Trinh, Huu; Flores, Sam

    2014-01-01

    For the past year, NASA Marshall Space Flight Center and Johnson Space Center have been working on a government version of a lunar lander design for the Resource Prospector Mission. A propulsion cold flow test system, representing an early flight design of the propulsion system, has been fabricated. The primary objective of the cold flow test is to simulate the Resource Prospector propulsion system operation through water flow testing and obtain data for anchoring analytical models. This effort will also provide an opportunity to develop a propulsion system mockup to examine hardware integration to a flight structure. This paper will report the work progress of the propulsion cold flow test system development and test preparation. At the time this paper is written, the initial waterhammer testing is underway. The initial assessment of the test data suggests that the results are as expected and have a similar trend with the pretest prediction. The test results will be reported in a future conference.

  4. Calculation of flow distribution in large radius ratio stages of axial flow turbines and comparison of theory and experiment

    NASA Technical Reports Server (NTRS)

    Herzog, J.

    1974-01-01

    A method of calculating stage parameters and flow distribution of axial turbines is described. The governing equations apply to space between the blade rows and are based on the assumption of rotationally symmetrical, compressible, adiabatic flow conditions. Results are presented for stage design and flow analysis calculations. Theoretical results from the calculation system are compared with experimental data from low pressure steam turbine tests.

  5. Inspiratory flow and intrapulmonary gas distribution

    SciTech Connect

    Rehder, K.; Knopp, T.J.; Brusasco, V.; Didier, E.P.

    1981-01-01

    The effect of flow of inspired gas on intrapulmonary gas distribution was examined by analysis of regional pulmonary /sup 133/Xe clearances and of total pulmonary /sup 133/Xe clearance measured at the mouth after equilibration of the lungs with /sup 133/Xe. Five awake healthy volunteers (24 to 40 yr of age) and another 5 healthy, anesthetized-paralyzed volunteers (26 to 28 yr of age) were studied while they were in the right lateral decubitus position. The awake subjects were studied at 3 inspiratory flows (0.4, 0.7, and 1.0 L/s) and the anesthetized-paralyzed subjects at 4 inspiratory flows (0.2, 0.5, 1.1, and 1.6 L/s). Interregional differences in /sup 133/Xe clearances along the vertical axis were significantly less during anesthesia-paralysis and mechanical ventilation than during spontaneous breathing in the awake state. No differences in the regional or total pulmonary /sup 133/Xe clearances were detected at these different flows in either of the two states, i.e., the difference between the awake and anesthetized-paralyzed states persisted.

  6. A void distribution model-flashing flow

    SciTech Connect

    Riznic, J.; Ishii, M.; Afgan, N.

    1987-01-01

    A new model for flashing flow based on wall nucleations is proposed here and the model predictions are compared with some experimental data. In order to calculate the bubble number density, the bubble number transport equation with a distributed source from the wall nucleation sites was used. Thus it was possible to avoid the usual assumption of a constant bubble number density. Comparisons of the model with the data shows that the model based on the nucleation site density correlation appears to be acceptable to describe the vapor generation in the flashing flow. For the limited data examined, the comparisons show rather satisfactory agreement without using a floating parameter to adjust the model. This result indicated that, at least for the experimental conditions considered here, the mechanistic predictions of the flashing phenomenon is possible on the present wall nucleation based model.

  7. THE DENSITY DISTRIBUTION IN TURBULENT BISTABLE FLOWS

    SciTech Connect

    Gazol, Adriana; Kim, Jongsoo E-mail: jskim@kasi.re.kr

    2013-03-01

    We numerically study the volume density probability distribution function (n-PDF) and the column density probability distribution function ({Sigma}-PDF) resulting from thermally bistable turbulent flows. We analyze three-dimensional hydrodynamic models in periodic boxes of 100 pc by side, where turbulence is driven in the Fourier space at a wavenumber corresponding to 50 pc. At low densities (n {approx}< 0.6 cm{sup -3}), the n-PDF is well described by a lognormal distribution for an average local Mach number ranging from {approx}0.2 to {approx}5.5. As a consequence of the nonlinear development of thermal instability (TI), the logarithmic variance of the distribution of the diffuse gas increases with M faster than in the well-known isothermal case. The average local Mach number for the dense gas (n {approx}> 7.1 cm{sup -3}) goes from {approx}1.1 to {approx}16.9 and the shape of the high-density zone of the n-PDF changes from a power law at low Mach numbers to a lognormal at high M values. In the latter case, the width of the distribution is smaller than in the isothermal case and grows slower with M. At high column densities, the {Sigma}-PDF is well described by a lognormal for all of the Mach numbers we consider and, due to the presence of TI, the width of the distribution is systematically larger than in the isothermal case but follows a qualitatively similar behavior as M increases. Although a relationship between the width of the distribution and M can be found for each one of the cases mentioned above, these relations are different from those of the isothermal case.

  8. Performance testing of the Silo Flow Model

    SciTech Connect

    Stadler, S.P.; O`Connor, D.; Gould, A.F.

    1994-12-31

    Several instruments are commercially available for on-line analysis of coal properties such as total moisture, ash, sulfur, and mineral matter content. These instruments have found use in coal cleaning and coal-fired utility applications. However, in many instances, the coal is stored in large bunkers or silos after on-line analysis, making the data gathered from on-line analysis a poor predictor of short-term coal quality due to the flow pattern and mixing within the silo. A computerized model, the Silo Flow Model, has been developed to model the flow of coal through a silo or bunker thus providing a prediction of the output coal quality based on on-line measurements of the quality of coal entering the silo. A test procedure was developed and demonstrated to test the performance of the Silo Flow Model. The testing was performed using controlled addition of silver nitrate to the coal, in conjunction with surface profile measurements using an array of ultrasonic gauges and data acquired from plant instrumentation. Results obtained from initial testing provided estimates of flow-related parameters used in the Silo flow Model. Similar test techniques are also used to compare predicted and actual silver content at the silo outlet as a measure of model performance. This paper describes test procedures used to validate the Silo Flow Model, the testing program, and the results obtained to data. The Silo Flow Model performance is discussed and compared against other modeling approaches.

  9. Stationary velocity distributions in traffic flows

    SciTech Connect

    Theoretical Division and Center for Nonlinear Studies,; Center for Polymer Studies and Department of Physics,

    1997-12-01

    We introduce a traffic flow model that incorporates clustering and passing. We obtain analytically the steady state characteristics of the flow from a Boltzmann-like equation. A single dimensionless parameter, R=c{sub 0}v{sub 0}t{sub 0} with c{sub 0} the concentration, v{sub 0} the velocity range, and t{sub 0}{sup {minus}1} the passing rate, determines the nature of the steady state. When R{lt}1, uninterrupted flow with single cars occurs. When R{gt}1, large clusters with average mass {l_angle}m{r_angle}{approximately}R{sup {alpha}} form, and the flux is J{approximately}R{sup {minus}{gamma}}. The initial distribution of slow cars governs the statistics. When P{sub 0}(v){approximately}v{sup {mu}} as v{r_arrow}0, the scaling exponents are {gamma}=1/({mu}+2), {alpha}=1/2 when {mu}{gt}0, and {alpha}=({mu}+1)/({mu}+2) when {mu}{lt}0. {copyright} {ital 1997} {ital The American Physical Society}

  10. LADEE Propulsion System Cold Flow Test

    NASA Technical Reports Server (NTRS)

    Williams, Jonathan Hunter; Chapman, Jack M.; Trinh, Hau, P.; Bell, James H.

    2013-01-01

    Lunar Atmosphere and Dust Environment Explorer (LADEE) is a NASA mission that will orbit the Moon. Its main objective is to characterize the atmosphere and lunar dust environment. The spacecraft development is being led by NASA Ames Research Center and scheduled for launch in 2013. The LADEE spacecraft will be operated with a bi-propellant hypergolic propulsion system using MMH and NTO as the fuel and oxidizer, respectively. The propulsion system utilizes flight-proven hardware on major components. The propulsion layout is composed of one 100-lbf main thruster and four 5-lbf RCS thrusters. The propellants are stored in four tanks (two parallel-connected tanks per propellant component). The propellants will be pressurized by regulated helium. A simulated propulsion system has been built for conducting cold flow test series to characterize the transient fluid flow of the propulsion system feed lines and to verify the critical operation modes, such as system priming, waterhammer, and crucial mission duty cycles. Propellant drainage differential between propellant tanks will also be assessed. Since the oxidizer feed line system has a higher flow demand than the fuel system does, the cold flow test focuses on the oxidizer system. The objective of the cold flow test is to simulate the LADEE propulsion fluid flow operation through water cold flow test and to obtain data for anchoring analytical models. The models will be used to predict the transient and steady state flow behaviors in the actual flight operations. The test activities, including the simulated propulsion test article, cold flow test, and analytical modeling, are being performed at NASA Marshall Space Flight Center. At the time of the abstract submission, the test article checkout is being performed. The test series will be completed by November, 2012

  11. Flowing electrolyte battery testing and evaluation

    SciTech Connect

    Butler, P.; Miller, D.; Verardo, A.

    1982-08-01

    A laboratory to evaluate the performance and cycle life of flowing electrolyte battery systems has been established at Sandia National Laboratories. Four unique flow batteries are being tested in the laboratory using a four-variable two-level factorial experimental plan. Two Exxon zinc bromine batteries and one Gould zinc bromine battery are under test. One NASA Redox battery is on test. This paper describes results obtained to date from the test program. Cycle history, efficiency values, and general performance observations for these batteries are reported. The factorial test program and available statistical results are also discussed.

  12. Flowing-electrolyte-battery testing and evaluation

    SciTech Connect

    Butler, P.C.; Miller, D.W.; Verardo, A.E.

    1982-01-01

    A laboratory to evaluate the performance and cycle life of flowing electrolyte battery systems has been established at Sandia National Laboratories. Four unique flow batteries are being tested in the laboratory using a four-variable two-level factorial experimental plan. Two Exxon zinc bromine batteries and one Gould zinc bromine battery are under test. One NASA Redox battery is on test. This paper describes results obtained to date from the test program. Cycle history, efficiency values, and general performance observations for these batteries are reported. The factorial test program and available statistical results are also discussed.

  13. Flowing electrolyte battery testing and evaluation

    NASA Astrophysics Data System (ADS)

    Butler, P. C.; Miller, D. W.; Verardo, A. E.

    A laboratory to evaluate the performance and cycle life of flowing electrolyte battery systems has been established at Sandia National Laboratories. Four unique flow batteries are being tested in the laboratory using a four-variable two-level factorial experimental plan. Two Exxon zinc bromine batteries and one Gould zinc bromine battery are under test. One NASA Redox battery is on test. This paper describes results obtained to date from the test program. Cycle history, efficiency values, and general performance observations for these batteries are reported. The factorial test program and available statistical results are also discussed.

  14. Counter-Flow Cooling Tower Test Cell

    NASA Astrophysics Data System (ADS)

    Dvořák, Lukáš; Nožička, Jiří

    2014-03-01

    The article contains a design of a functional experimental model of a cross-flow mechanical draft cooling tower and the results and outcomes of measurements. This device is primarily used for measuring performance characteristics of cooling fills, but with a simple rebuild, it can be used for measuring other thermodynamic processes that take part in so-called wet cooling. The main advantages of the particular test cell lie in the accuracy, size, and the possibility of changing the water distribution level. This feature is very useful for measurements of fills of different heights without the influence of the spray and rain zone. The functionality of this test cell has been verified experimentally during assembly, and data from the measurement of common film cooling fills have been compared against the results taken from another experimental line. For the purpose of evaluating the data gathered, computational scripts were created in the MATLAB numerical computing environment. The first script is for exact calculation of the thermal balance of the model, and the second is for determining Merkel's number via Chebyshev's method.

  15. Quantifiable Lateral Flow Assay Test Strips

    NASA Technical Reports Server (NTRS)

    2003-01-01

    As easy to read as a home pregnancy test, three Quantifiable Lateral Flow Assay (QLFA) strips used to test water for E. coli show different results. The brightly glowing control line on the far right of each strip indicates that all three tests ran successfully. But the glowing test line on the middle left and bottom strips reveal their samples were contaminated with E. coli bacteria at two different concentrations. The color intensity correlates with concentration of contamination.

  16. Measurements of Gas Bubble Size Distributions in Flowing Liquid Mercury

    SciTech Connect

    Wendel, Mark W; Riemer, Bernie; Abdou, Ashraf A

    2012-01-01

    ABSTRACT Pressure waves created in liquid mercury pulsed spallation targets have been shown to induce cavitation damage on the target container. One way to mitigate such damage would be to absorb the pressure pulse energy into a dispersed population of small bubbles, however, measuring such a population in mercury is difficult since it is opaque and the mercury is involved in a turbulent flow. Ultrasonic measurements have been attempted on these types of flows, but the flow noise can interfere with the measurement, and the results are unverifiable and often unrealistic. Recently, a flow loop was built and operated at Oak Ridge National Labarotory to assess the capability of various bubbler designs to deliver an adequate population of bubbles to mitigate cavitation damage. The invented diagnostic technique involves flowing the mercury with entrained gas bubbles in a steady state through a horizontal piping section with a glass-window observation port located on the top. The mercury flow is then suddenly stopped and the bubbles are allowed to settle on the glass due to buoyancy. Using a bright-field illumination and a high-speed camera, the arriving bubbles are detected and counted, and then the images can be processed to determine the bubble populations. After using this technique to collect data on each bubbler, bubble size distributions were built for the purpose of quantifying bubbler performance, allowing the selection of the best bubbler options. This paper presents the novel procedure, photographic technique, sample visual results and some example bubble size distributions. The best bubbler options were subsequently used in proton beam irradiation tests performed at the Los Alamos National Laboratory. The cavitation damage results from the irradiated test plates in contact with the mercury are available for correlation with the bubble populations. The most effective mitigating population can now be designed into prototypical geometries for implementation into

  17. Smoothing Methods for Estimating Test Score Distributions.

    ERIC Educational Resources Information Center

    Kolen, Michael J.

    1991-01-01

    Estimation/smoothing methods that are flexible enough to fit a wide variety of test score distributions are reviewed: kernel method, strong true-score model-based method, and method that uses polynomial log-linear models. Applications of these methods include describing/comparing test score distributions, estimating norms, and estimating…

  18. Columbia University flow instability experimental program: Volume 6. Single annulus tests, transient test program

    SciTech Connect

    Dougherty, T.; Maciuca, C.; McAssey, E.V. Jr.; Reddy, D.G.; Yang, B.W.

    1992-09-01

    The coolant in the Savannah River Site (SRS) production nuclear reactor assemblies is circulated as a subcooled liquid under normal operating conditions. This coolant is evenly distributed throughout multiple annular flow channels with a uniform pressure profile across each coolant flow channel. During the postulated Loss of Coolant Accident (LOCA), which is initiated by a hypothetical guillotine pipe break, the coolant flow through the reactor assemblies is significantly reduced. The flow reduction and accompanying power reduction (after shutdown is initiated) occur in the first 1 to 2 seconds of the LOCA. This portion of the LOCA is referred to as the Flow Instability phase. This report presents the experimental results for the transient portion of the single annulus test program. The test program was designed to investigate the onset of flow instability in an annular geometry similar to the MARK 22 reactor. The test program involved testing of both a ribless heater and a ribbed heater under steady state as well as transient conditions. The ribbed heater testing is currently underway and will be reported separately. The steady state portion of this test program with ribless heater was completed and reported in report No. CU-HTRF-T3A. The present report presents transient test results obtained from a ribless, uniform annulus test section. A total of thirty five transients were conducted with six cases in which flow excursion occurred. No unstable conditions resulted for tests in which the steady state Q{sub ratio} OFI limit was not exceeded.

  19. Boundary layer flow visualization for flight testing

    NASA Technical Reports Server (NTRS)

    Obara, Clifford J.

    1986-01-01

    Flow visualization is used extensively in flight testing to determine aerodynamic characteristics such as surface flow direction and boundary layer state. Several visualization techniques are available to the aerodynamicist. Two of the most popular are oil flows and sublimating chemicals. Oil is used to visualize boundary layer transition, shock wave location, regions of separated flow, and surface flow direction. Boundary layer transition can also be visualized with sublimating chemicals. A summary of these two techniques is discussed, and the use of sublimating chemicals is examined in some detail. The different modes of boundary layer transition are characterized by different patterns in the sublimating chemical coating. The discussion includes interpretation of these chemical patterns and the temperature and velocity operating limitations of the chemical substances. Information for selection of appropriate chemicals for a desired set of flight conditions is provided.

  20. Precipitator inlet particulate distribution flow analysis

    SciTech Connect

    LaRose, J.A.; Averill, A.

    1994-12-31

    The B and W Rothemuhle precipitators located at PacifiCorp`s Wyodak Generating Station in Gillette, Wyoming have, for the past two years, been experiencing discharge wire breakage. The breakage is due to corrosion of the wires: however, the exact cause of the corrosion is unknown. One aspect thought to contribute to the problem is an unbalance of ash loading among the four precipitators. Plant operation has revealed that the ash loading to precipitator C appears to be the heaviest of the four casing, and also appears to have the most severe corrosion. Data from field measurements showed that the gas flows to the four precipitators are fairly uniform, within {+-}9% of the average. The ash loading data showed a large maldistribution among the precipitators. Precipitator C receives 60% more ash than the next heaviest loaded precipitator. A numerical model was created which showed the same results. The model was then utilized to determine design modifications to the existing flue and turning vanes to improve the ash loading distribution. The resulting design was predicted to improve the ash loading to all the precipitators, within {+-}10% of the average.

  1. Cold-Flow Propulsion Research Test

    NASA Technical Reports Server (NTRS)

    1997-01-01

    An engineer at the Marshall Space Flight Center (MSFC) Wind Tunnel Facility uses lasers to measure the velocity and gradient distortion across an eight inch curved pipe with joints and turning valves during a cold-flow propulsion research test; simulating the conditions found in the X-33's hydrogen feedline. Lasers are used because they are non-intrusive and do not disturb the flow like a probe would. The feedline supplies propellants to the turbo pump. The purpose of this project was to design the feedline to provide uniform flow into the turbo pump.

  2. Distributing Radiant Heat in Insulation Tests

    NASA Technical Reports Server (NTRS)

    Freitag, H. J.; Reyes, A. R.; Ammerman, M. C.

    1986-01-01

    Thermally radiating blanket of stepped thickness distributes heat over insulation sample during thermal vacuum testing. Woven of silicon carbide fibers, blanket spreads heat from quartz lamps evenly over insulation sample. Because of fewer blanket layers toward periphery of sample, more heat initially penetrates there for more uniform heat distribution.

  3. Numerical Modeling of Flow Distribution in Micro-Fluidics Systems

    NASA Technical Reports Server (NTRS)

    Majumdar, Alok; Cole, Helen; Chen, C. P.

    2005-01-01

    This paper describes an application of a general purpose computer program, GFSSP (Generalized Fluid System Simulation Program) for calculating flow distribution in a network of micro-channels. GFSSP employs a finite volume formulation of mass and momentum conservation equations in a network consisting of nodes and branches. Mass conservation equation is solved for pressures at the nodes while the momentum conservation equation is solved at the branches to calculate flowrate. The system of equations describing the fluid network is solved by a numerical method that is a combination of the Newton-Raphson and successive substitution methods. The numerical results have been compared with test data and detailed CFD (computational Fluid Dynamics) calculations. The agreement between test data and predictions is satisfactory. The discrepancies between the predictions and test data can be attributed to the frictional correlation which does not include the effect of surface tension or electro-kinetic effect.

  4. LaRC Separate Flow Testing Status

    NASA Technical Reports Server (NTRS)

    Seiner, Jack

    2000-01-01

    The main goal of this presentation is to give some of the objectives of the testing program. This includes: develop jet noise data base for separate flow nozzles with bypass ratio's 5 to 14; evaluate effect of pylon on noise; develop low performance impact noise suppression concepts; and evaluate potential for active control of jet noise.

  5. Characterization of Flow Bench Engine Testing

    NASA Astrophysics Data System (ADS)

    Voris, Alex; Riley, Lauren; Puzinauskas, Paul

    2015-11-01

    This project was an attempt at characterizing particle image velocimetry (PIV) and swirl-meter test procedures. The flow direction and PIV seeding were evaluated for in-cylinder steady state flow of a spark ignition engine. For PIV seeding, both wet and dry options were tested. The dry particles tested were baby powder, glass particulate, and titanium dioxide. The wet particles tested were fogs created with olive oil, vegetable oil, DEHS, and silicon oil. The seeding was evaluated at 0.1 and 0.25 Lift/Diameter and at cylinder pressures of 10, 25 and 40 inches of H2O. PIV results were evaluated through visual and fluid momentum comparisons. Seeding particles were also evaluated based on particle size and cost. It was found that baby powder and glass particulate were the most effective seeding options for the current setup. The oil fogs and titanium dioxide were found to deposit very quickly on the mock cylinder and obscure the motion of the particles. Based on initial calculations and flow measurements, the flow direction should have a negligible impact on PIV and swirl-meter results. The characterizations found in this project will be used in future engine research examining the effects of intake port geometry on in-cylinder fluid motion and exhaust gas recirculation tolerances. Thanks to NSF site grant #1358991.

  6. Resource Prospector Propulsion System Cold Flow Testing

    NASA Technical Reports Server (NTRS)

    Williams, Hunter; Holt, Kim; Addona, Brad; Trinh, Huu

    2015-01-01

    Resource Prospector (RP) is a NASA mission being led by NASA Ames Research Center with current plans to deliver a scientific payload package aboard a rover to the lunar surface. As part of an early risk reduction activity, Marshall Space Flight Center (MSFC) and Johnson Space Flight Center (JSC) have jointly developed a government-version concept of a lunar lander for the mission. The spacecraft consists of two parts, the lander and the rover which carries the scientific instruments. The lander holds the rover during launch, cruise, and landing on the surface. Following terminal descent and landing the lander portion of the spacecraft become dormant after the rover embarks on the science mission. The lander will be equipped with a propulsion system for lunar descent and landing, as well as trajectory correction and attitude control maneuvers during transit to the moon. Hypergolic propellants monomethyl hydrazine and nitrogen tetroxide will be used to fuel sixteen 70-lbf descent thrusters and twelve 5-lbf attitude control thrusters. A total of four metal-diaphragm tanks, two per propellant, will be used along with a high-pressure composite-overwrapped pressure vessel for the helium pressurant gas. Many of the major propulsion system components are heritage missile hardware obtained by NASA from the Air Force. In parallel with the flight system design activities, a simulated propulsion system based on flight drawings was built for conducting a series of water flow tests to characterize the transient fluid flow of the propulsion system feed lines and to verify the critical operation modes such as system priming, waterhammer, and crucial mission duty cycles. The primary objective of the cold flow testing was to simulate the RP propulsion system fluid flow operation through water flow testing and to obtain data for anchoring analytical models. The models will be used to predict the transient and steady state flow behaviors in the actual flight operations. All design and

  7. Vascular structure determines pulmonary blood flow distribution

    NASA Technical Reports Server (NTRS)

    Hlastala, M. P.; Glenny, R. W.

    1999-01-01

    Scientific knowledge develops through the evolution of new concepts. This process is usually driven by new methodologies that provide observations not previously available. Understanding of pulmonary blood flow determinants advanced significantly in the 1960s and is now changing rapidly again, because of increased spatial resolution of regional pulmonary blood flow measurements.

  8. SSME hot gas manifold flow comparison test

    NASA Technical Reports Server (NTRS)

    Cox, G. B., Jr.; Dill, C. C.

    1988-01-01

    An account is given of the High Pressure Fuel Turbopump (HPFT) component of NASA's Alternate Turbopump Development effort, which is aimed at the proper aerodynamic integration of the current Phase II three-duct SSME Hot Gas Manifold (HGM) and the future 'Phase II-plus' two-duct HGM. Half-scale water flow tests of both HGM geometries were conducted to provide initial design data for the HPFT. The results reveal flowfield results and furnish insight into the performance differences between the two HGM flowpaths. Proper design of the HPFT can potentially secure significant flow improvements in either HGM configuration.

  9. Forced Flow Flame-Spreading Test (FFFT)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Forced Flow Flame-Spreading Test was designed to study flame spreading over solid fuels when air is flowing at a low speed in the same direction as the flame spread. Previous research has shown that in low-speed concurrent airflows, some materials are more flammable in microgravity than earth. This image shows a 10-cm flame in microgravity that burns almost entirely blue on both sides of a thin sheet of paper. The glowing thermocouple in the lower half of the flame provides temperature measurements.

  10. A flow path model for regional water distribution optimization

    NASA Astrophysics Data System (ADS)

    Cheng, Wei-Chen; Hsu, Nien-Sheng; Cheng, Wen-Ming; Yeh, William W.-G.

    2009-09-01

    We develop a flow path model for the optimization of a regional water distribution system. The model simultaneously describes a water distribution system in two parts: (1) the water delivery relationship between suppliers and receivers and (2) the physical water delivery network. In the first part, the model considers waters from different suppliers as multiple commodities. This helps the model clearly describe water deliveries by identifying the relationship between suppliers and receivers. The physical part characterizes a physical water distribution network by all possible flow paths. The flow path model can be used to optimize not only the suppliers to each receiver but also their associated flow paths for supplying water. This characteristic leads to the optimum solution that contains the optimal scheduling results and detailed information concerning water distribution in the physical system. That is, the water rights owner, water quantity, water location, and associated flow path of each delivery action are represented explicitly in the results rather than merely as an optimized total flow quantity in each arc of a distribution network. We first verify the proposed methodology on a hypothetical water distribution system. Then we apply the methodology to the water distribution system associated with the Tou-Qian River basin in northern Taiwan. The results show that the flow path model can be used to optimize the quantity of each water delivery, the associated flow path, and the water trade and transfer strategy.

  11. Traffic Flow Density Distribution Based on FEM

    NASA Astrophysics Data System (ADS)

    Ma, Jing; Cui, Jianming

    In analysis of normal traffic flow, it usually uses the static or dynamic model to numerical analyze based on fluid mechanics. However, in such handling process, the problem of massive modeling and data handling exist, and the accuracy is not high. Finite Element Method (FEM) is a production which is developed from the combination of a modern mathematics, mathematics and computer technology, and it has been widely applied in various domain such as engineering. Based on existing theory of traffic flow, ITS and the development of FEM, a simulation theory of the FEM that solves the problems existing in traffic flow is put forward. Based on this theory, using the existing Finite Element Analysis (FEA) software, the traffic flow is simulated analyzed with fluid mechanics and the dynamics. Massive data processing problem of manually modeling and numerical analysis is solved, and the authenticity of simulation is enhanced.

  12. Bilateral Trade Flows and Income Distribution Similarity

    PubMed Central

    2016-01-01

    Current models of bilateral trade neglect the effects of income distribution. This paper addresses the issue by accounting for non-homothetic consumer preferences and hence investigating the role of income distribution in the context of the gravity model of trade. A theoretically justified gravity model is estimated for disaggregated trade data (Dollar volume is used as dependent variable) using a sample of 104 exporters and 108 importers for 1980–2003 to achieve two main goals. We define and calculate new measures of income distribution similarity and empirically confirm that greater similarity of income distribution between countries implies more trade. Using distribution-based measures as a proxy for demand similarities in gravity models, we find consistent and robust support for the hypothesis that countries with more similar income-distributions trade more with each other. The hypothesis is also confirmed at disaggregated level for differentiated product categories. PMID:27137462

  13. Bilateral Trade Flows and Income Distribution Similarity.

    PubMed

    Martínez-Zarzoso, Inmaculada; Vollmer, Sebastian

    2016-01-01

    Current models of bilateral trade neglect the effects of income distribution. This paper addresses the issue by accounting for non-homothetic consumer preferences and hence investigating the role of income distribution in the context of the gravity model of trade. A theoretically justified gravity model is estimated for disaggregated trade data (Dollar volume is used as dependent variable) using a sample of 104 exporters and 108 importers for 1980-2003 to achieve two main goals. We define and calculate new measures of income distribution similarity and empirically confirm that greater similarity of income distribution between countries implies more trade. Using distribution-based measures as a proxy for demand similarities in gravity models, we find consistent and robust support for the hypothesis that countries with more similar income-distributions trade more with each other. The hypothesis is also confirmed at disaggregated level for differentiated product categories. PMID:27137462

  14. Review of flow battery testing at Sandia

    SciTech Connect

    Butler, P.C.; Miller, D.W.; Robinson, C.E.; Rodriguez, G.P.

    1984-01-01

    Sandia National Laboratories is evaluating prototype zinc/bromine, Redox, and zinc/ferricyanide flowing electrolyte batteries and cells. This paper will update previous reports of test results of two Exxon zinc/bromine batteries and one NASA Redox iron/chromium battery. Two 60-sq. cm. zinc/ferricyanide cells from Lockheed Missiles and Space Co. are also being evaluated. Performance, life, and operating data will be described for these batteries and cells.

  15. Power flow control using distributed saturable reactors

    DOEpatents

    Dimitrovski, Aleksandar D.

    2016-02-13

    A magnetic amplifier includes a saturable core having a plurality of legs. Control windings wound around separate legs are spaced apart from each other and connected in series in an anti-symmetric relation. The control windings are configured in such a way that a biasing magnetic flux arising from a control current flowing through one of the plurality of control windings is substantially equal to the biasing magnetic flux flowing into a second of the plurality of control windings. The flow of the control current through each of the plurality of control windings changes the reactance of the saturable core reactor by driving those portions of the saturable core that convey the biasing magnetic flux in the saturable core into saturation. The phasing of the control winding limits a voltage induced in the plurality of control windings caused by a magnetic flux passing around a portion of the saturable core.

  16. Sultan - forced flow, high field test facility

    SciTech Connect

    Horvath, I.; Vecsey, G.; Weymuth, P.; Zellweger, J.

    1981-09-01

    Three European laboratories: CNEN (Frascati, I) ECN (Petten, NL) and SIN (Villigen, CH) decided to coordinate their development efforts and to install a common high field forced flow test facility at Villigen Switzerland. The test facility SULTAN (Supraleiter Testanlage) is presently under construction. As a first step, an 8T/1m bore solenoid with cryogenic periphery will be ready in 1981. The cryogenic system, data acquisition system and power supplies which are contributed by SIN are described. Experimental feasibilities, including cooling, and instrumentation are reviewed. Progress of components and facility construction is described. Planned extension of the background field up to 12T by insert coils is outlined. 5 refs.

  17. F-16XL-2 Supersonic Laminar Flow Control Flight Test Experiment

    NASA Technical Reports Server (NTRS)

    Anders, Scott G.; Fischer, Michael C.

    1999-01-01

    The F-16XL-2 Supersonic Laminar Flow Control Flight Test Experiment was part of the NASA High-Speed Research Program. The goal of the experiment was to demonstrate extensive laminar flow, to validate computational fluid dynamics (CFD) codes and design methodology, and to establish laminar flow control design criteria. Topics include the flight test hardware and design, airplane modification, the pressure and suction distributions achieved, the laminar flow achieved, and the data analysis and code correlation.

  18. Declarative flow control for distributed instrumentation

    SciTech Connect

    Parvin, Bahram; Taylor, John; Fontenay, Gerald; Callahan, Daniel

    2001-06-01

    We have developed a 'microscopy channel' to advertise a unique set of on-line scientific instruments and to let users join a particular session, perform an experiment, collaborate with other users, and collect data for further analysis. The channel is a collaborative problem solving environment (CPSE) that allows for both synchronous and asynchronous collaboration, as well as flow control for enhanced scalability. The flow control is a declarative feature that enhances software functionality at the experimental scale. Our testbed includes several unique electron and optical microscopes with applications ranging from material science to cell biology. We have built a system that leverages current commercial CORBA services, Web Servers, and flow control specifications to meet diverse requirements for microscopy and experimental protocols. In this context, we have defined and enhanced Instrument Services (IS), Exchange Services (ES), Computational Services (CS), and Declarative Services (DS) that sit on top of CORBA and its enabling services (naming, trading, security, and notification) IS provides a layer of abstraction for controlling any type of microscope. ES provides a common set of utilities for information management and transaction. CS provides the analytical capabilities needed for online microscopy. DS provides mechanisms for flow control for improving the dynamic behavior of the system.

  19. Blood flow distribution in submerged and surface-swimming ducks.

    PubMed

    Stephenson, R; Jones, D R

    1992-05-01

    Observations that the response of the avian heart rate to submergence varies under different circumstances have led to speculation about variability of blood flow distribution during voluntary dives. We used a radiological imaging technique to examine the patterns of circulating blood flow in captive redhead ducks (Aythya americana) during rest, swimming, escape dives, forced dives and trapped escape dives and have shown that blood flow distribution in escape dives was the same as that in ducks swimming at the water surface. The response during trapped escape dives, however, was highly variable. Blood pressure was unchanged from the resting value during all activities. Predictions made about blood flow distribution during unrestrained dives on the basis of heart rate and other indirect data were confirmed in this study. However, the trapped escape dive responses indicated that heart rate alone is not always a reliable indicator of tissue blood flow in exercising ducks. PMID:1602277

  20. CFD study on electrolyte distribution in redox flow batteries

    NASA Astrophysics Data System (ADS)

    Bortolin, S.; Toninelli, P.; Maggiolo, D.; Guarnieri, M.; Del, D., Col

    2015-11-01

    The most important component in a redox flow battery (RFB) cell is the MEA (membrane electrode assembly), a sandwich consisting of two catalyzed electrodes with an interposed polymeric membrane. In order to allow electrolyte flow toward the electroactive sites, the electrodes have a porous structure that can be obtained with carbon base materials such as carbon felts. The RFB cell is closed by two plates containing the distribution flow channels. Considering that a uniform electrolyte distribution in the reaction region is a prerequisite for high-efficiency operation, the flow pattern is an important parameter to be investigated for the optimization of the cell. In the present work, the effect of different channels patterns on the electrolyte distribution and on the pressure drop is numerically investigated. Three-dimensional simulations have been carried out with ANSYS Fluent code and four different layouts have been considered. Calculations have been performed both in the distribution channels and in the felt porous region.

  1. Velocity distribution in horizontal slug flow

    SciTech Connect

    Kvernvold, O.; Saasen, A.; Selmor-Olsen, S.; Sontvedt, T.; Vindoy, V.

    1984-08-01

    An experimental device for measurement of the velocity distribution in a two-phase slug is developed. Velocity profiles both in the film and the liquid slug besides velocity variation along the pipe bottom (at a distance of 1 mm) through the slug front are presented.

  2. Experimental evaluation of blockage ratio and plenum evacuation system flow effects on pressure distribution for bodies of revolution in 0.1 scale model test section of NASA Lewis Research Center's proposed altitude wind tunnel

    NASA Technical Reports Server (NTRS)

    Burley, Richard R.; Harrington, Douglas E.

    1987-01-01

    An experimental investigation was conducted in the slotted test section of the 0.1-scale model of the proposed Altitude Wind Tunnel to evaluate wall interference effects at tunnel Mach numbers from 0.70 to 0.95 on bodies of revolution with blockage rates of 0.43, 3, 6, and 12 percent. The amount of flow that had to be removed from the plenum chamber (which surrounded the slotted test section) by the plenum evacuation system (PES) to eliminate wall interference effects was determined. The effectiveness of tunnel reentry flaps in removing flow from the plenum chamber was examined. The 0.43-percent blockage model was the only one free of wall interference effects with no PES flow. Surface pressures on the forward part of the other models were greater than interference-free results and were not influenced by PES flow. Interference-free results were achieved on the aft part of the 3- and 6-percent blockage models with the proper amount of PES flow. The required PES flow was substantially reduced by opening the reentry flaps.

  3. Scaled Rocket Testing in Hypersonic Flow

    NASA Technical Reports Server (NTRS)

    Dufrene, Aaron; MacLean, Matthew; Carr, Zakary; Parker, Ron; Holden, Michael; Mehta, Manish

    2015-01-01

    NASA's Space Launch System (SLS) uses four clustered liquid rocket engines along with two solid rocket boosters. The interaction between all six rocket exhaust plumes will produce a complex and severe thermal environment in the base of the vehicle. This work focuses on a recent 2% scale, hot-fire SLS base heating test. These base heating tests are short-duration tests executed with chamber pressures near the full-scale values with gaseous hydrogen/oxygen engines and RSRMV analogous solid propellant motors. The LENS II shock tunnel/Ludwieg tube tunnel was used at or near flight duplicated conditions up to Mach 5. Model development was strongly based on the Space Shuttle base heating tests with several improvements including doubling of the maximum chamber pressures and duplication of freestream conditions. Detailed base heating results are outside of the scope of the current work, rather test methodology and techniques are presented along with broader applicability toward scaled rocket testing in supersonic and hypersonic flow.

  4. Distributed energy storage: Time-dependent tree flow design

    NASA Astrophysics Data System (ADS)

    Bejan, A.; Ziaei, S.; Lorente, S.

    2016-05-01

    This article proposes "distributed energy storage" as a basic design problem of distributing energy storage material on an area. The energy flows by fluid flow from a concentrated source to points (users) distributed equidistantly on the area. The flow is time-dependent. Several scenarios are analyzed: sensible-heat storage, latent-heat storage, exergy storage vs energy storage, and the distribution of a finite supply of heat transfer surface between the source fluid and the distributed storage material. The chief conclusion is that the finite amount of storage material should be distributed proportionally with the distribution of the flow rate of heating agent arriving on the area. The total time needed by the source stream to "invade" the area is cumulative (the sum of the storage times required at each storage site) and depends on the energy distribution paths and the sequence in which the users are served by the source stream. Directions for future designs of distributed storage and retrieval are outlined in the concluding section.

  5. Interconnection Testing of Distributed Resources: Preprint

    SciTech Connect

    Kroposki, B.; Basso, T.; DeBlasio, R.

    2004-02-01

    With the publication of IEEE 1547-2003(TM) Standard for Interconnecting Distributed Resources With Electric Power Systems, the electric power industry has a need to develop tests and procedures to verify that interconnection equipment meets 1547 technical requirements. A new standard, IEEE P1547.1(TM), is being written to give detailed tests and procedures for confirming that equipment meets the interconnection requirements. The National Renewable Energy Laboratory has been validating test procedures being developed as part of IEEE P1547.1. As work progresses on the validation of those procedures, information and test reports are passed on to the working group of IEEE P1547.1 for future revisions.

  6. Testing the Markov hypothesis in fluid flows

    NASA Astrophysics Data System (ADS)

    Meyer, Daniel W.; Saggini, Frédéric

    2016-05-01

    Stochastic Markov processes are used very frequently to model, for example, processes in turbulence and subsurface flow and transport. Based on the weak Chapman-Kolmogorov equation and the strong Markov condition, we present methods to test the Markov hypothesis that is at the heart of these models. We demonstrate the capabilities of our methodology by testing the Markov hypothesis for fluid and inertial particles in turbulence, and fluid particles in the heterogeneous subsurface. In the context of subsurface macrodispersion, we find that depending on the heterogeneity level, Markov models work well above a certain scale of interest for media with different log-conductivity correlation structures. Moreover, we find surprising similarities in the velocity dynamics of the different media considered.

  7. Flow distributions and spatial correlations in human brain capillary networks

    NASA Astrophysics Data System (ADS)

    Lorthois, Sylvie; Peyrounette, Myriam; Larue, Anne; Le Borgne, Tanguy

    2015-11-01

    The vascular system of the human brain cortex is composed of a space filling mesh-like capillary network connected upstream and downstream to branched quasi-fractal arterioles and venules. The distribution of blood flow rates in these networks may affect the efficiency of oxygen transfer processes. Here, we investigate the distribution and correlation properties of blood flow velocities from numerical simulations in large 3D human intra-cortical vascular network (10000 segments) obtained from an anatomical database. In each segment, flow is solved from a 1D non-linear model taking account of the complex rheological properties of blood flow in microcirculation to deduce blood pressure, blood flow and red blood cell volume fraction distributions throughout the network. The network structural complexity is found to impart broad and spatially correlated Lagrangian velocity distributions, leading to power law transit time distributions. The origins of this behavior (existence of velocity correlations in capillary networks, influence of the coupling with the feeding arterioles and draining veins, topological disorder, complex blood rheology) are studied by comparison with results obtained in various model capillary networks of controlled disorder. ERC BrainMicroFlow GA615102, ERC ReactiveFronts GA648377.

  8. Experimental Investigation on Liquid Metal Flow Distribution in Insulating Manifold under Uniform Magnetic Field

    NASA Astrophysics Data System (ADS)

    Miura, Masato; Ueki, Yoshitaka; Yokomine, Takehiko; Kunugi, Tomoaki

    2012-11-01

    Magnetohydrodynamics (MHD) problem which is caused by interaction between electrical conducting fluid flow and the magnetic field is one of the biggest problem in the liquid metal blanket of the fusion reactor. In the liquid metal blanket concept, it is necessary to distribute liquid metal flows uniformly in the manifold because imbalance of flow rates should affect the heat transfer performance directly, which leads to safety problem. While the manifold is insulated electrically as well as the flow duct, the 3D-MHD effect on the flowing liquid metal in the manifold is more apparent than that in straight duct. With reference to the flow distribution in this concept, the liquid metal flow in the electrical insulating manifold under the uniform transverse magnetic field is investigated experimentally. In this study, GaInSn is selected as working fluid. The experimental system includes the electrical magnet and the manifold test section which is made of acrylic resin for perfectly electrical insulation. The liquid metal flows in a non-symmetric 180°-turn with manifold, which consists of one upward channel and two downward channels. The flow rates in each channel are measured by electromagnetic flow meters for several combinations Reynolds number and Hartman number. The effects of magnetic field on the uniformity of flow distribution are cleared.

  9. Flow boiling test of GDP replacement coolants

    SciTech Connect

    Park, S.H.

    1995-08-01

    The tests were part of the CFC replacement program to identify and test alternate coolants to replace CFC-114 being used in the uranium enrichment plants at Paducah and Portsmouth. The coolants tested, C{sub 4}F{sub 10} and C{sub 4}F{sub 8}, were selected based on their compatibility with the uranium hexafluoride process gas and how well the boiling temperature and vapor pressure matched that of CFC-114. However, the heat of vaporization of both coolants is lower than that of CFC-114 requiring larger coolant mass flow than CFC-114 to remove the same amount of heat. The vapor pressure of these coolants is higher than CFC-114 within the cascade operational range, and each coolant can be used as a replacement coolant with some limitation at 3,300 hp operation. The results of the CFC-114/C{sub 4}F{sub 10} mixture tests show boiling heat transfer coefficient degraded to a minimum value with about 25% C{sub 4}F{sub 10} weight mixture in CFC-114 and the degree of degradation is about 20% from that of CFC-114 boiling heat transfer coefficient. This report consists of the final reports from Cudo Technologies, Ltd.

  10. Quantitative velocity distributions via nuclear magnetic resonance flow metering

    NASA Astrophysics Data System (ADS)

    O'Neill, Keelan T.; Fridjonsson, Einar O.; Stanwix, Paul L.; Johns, Michael L.

    2016-08-01

    We demonstrate the use of Tikhonov regularisation as a data inversion technique to determine the velocity distributions of flowing liquid streams. Regularisation is applied to the signal produced by a nuclear magnetic resonance (NMR) flow measurement system consisting of a pre-polarising permanent magnet located upstream of an Earth's magnetic field NMR detection coil. A simple free induction decay (FID) NMR signal is measured for the flowing stream in what is effectively a 'time-of-flight' measurement. The FID signal is then modelled as a function of fluid velocity and acquisition time, enabling determination of the velocity probability distributions via regularisation. The mean values of these velocity distributions were successfully validated against in-line rotameters. The ability to quantify multi-modal velocity distributions was also demonstrated using a two-pipe system.

  11. Quantitative velocity distributions via nuclear magnetic resonance flow metering.

    PubMed

    O'Neill, Keelan T; Fridjonsson, Einar O; Stanwix, Paul L; Johns, Michael L

    2016-08-01

    We demonstrate the use of Tikhonov regularisation as a data inversion technique to determine the velocity distributions of flowing liquid streams. Regularisation is applied to the signal produced by a nuclear magnetic resonance (NMR) flow measurement system consisting of a pre-polarising permanent magnet located upstream of an Earth's magnetic field NMR detection coil. A simple free induction decay (FID) NMR signal is measured for the flowing stream in what is effectively a 'time-of-flight' measurement. The FID signal is then modelled as a function of fluid velocity and acquisition time, enabling determination of the velocity probability distributions via regularisation. The mean values of these velocity distributions were successfully validated against in-line rotameters. The ability to quantify multi-modal velocity distributions was also demonstrated using a two-pipe system. PMID:27343484

  12. Final report for the flow excursion follow-on testing

    SciTech Connect

    Nash, C.A.; Walters, T.W.

    1992-08-05

    The purpose of the Mark 22 Flow Excursion Follow-On testing was to investigate the theory that approximately 15% of the flow bypassed the primary flow channels in previous testing, whereas the design called for only a 3% bypass. The results of the follow-on tests clearly confirmed this theory. The testing was performed in two phases. During the first phase, characterization tests performed during the earlier test program were repeated.

  13. Pressure distribution in unsteady sink and source flows.

    PubMed

    Voropayev, S I

    2015-05-01

    Basic flow generated in a viscous incompressible fluid by a "point" sink (source) of mass is revised. In practice, such flow can be modeled by sucking (pushing) fluid from a thin tube with a small porous sphere at one end. Intuitively, by sucking (pushing) fluid, one creates low (high) pressure near the origin and a positive (negative) radial pressure gradient drives the fluid to (from) the origin. A simple analysis, however, shows that the pressure distribution for both steady flows is the same. Then a question arises: How does the fluid "know" in what direction to flow? To explain this "paradox" an unsteady flow is considered and the pressure terms responsible for the flow direction are derived. PMID:26066255

  14. Applying well flow adapted filtering to transient pumping tests

    NASA Astrophysics Data System (ADS)

    Zech, Alraune; Attinger, Sabine

    2014-05-01

    Transient pumping tests are often used to estimate porous medium characteristics like hydraulic conductivity and storativity. The interpretation of pumping test drawdowns is based on methods which are normally developed under the assumption of homogeneous porous media. However aquifer heterogeneity strongly impacts on well flow pattern, in particular in the vicinity of the pumping well. The purpose of this work is to present a method to interpret drawdowns of transient pumping tests in heterogeneous porous media. With this method we are able to describe the effects that statistical quantities like variance and correlation length have on pumping test drawdowns. Furthermore it allows inferring on the statistical parameters of aquifer heterogeneity from drawdown data by invers estimation, which is not possible using methods for homogeneous media like Theis' solution. The method is based on a representative description of hydraulic conductivity for radial flow regimes. It is derived from a well flow adapted filtering procedure (Coarse Graining), where the heterogeneity of hydraulic conductivity is assumed to be log-normal distributed with a Gaussian correlation structure. applying the up scaled hydraulic conductivity to the groundwater flow equation results in a hydraulic head which depends on the statistical parameters of the porous medium. It describes the drawdown of a transient pumping test in heterogeneous media. We used an ensemble of transient pumping test simulations to verify the up scaled drawdown solution. We generated transient pumping tests in heterogeneous media for various values of the statistical parameters variance and correlation length and evaluated their impact on the drawdown behavior as well as on the temporal evolution. We further examined the impact of several aspects like the location of an observation well or the local conductivity at the pumping well on the drawdown behavior. This work can be understood as an expansion of the work of Zech et

  15. Two-dimensional automatic measurement for nozzle flow distribution using improved ultrasonic sensor.

    PubMed

    Zhai, Changyuan; Zhao, Chunjiang; Wang, Xiu; Wang, Ning; Zou, Wei; Li, Wei

    2015-01-01

    Spray deposition and distribution are affected by many factors, one of which is nozzle flow distribution. A two-dimensional automatic measurement system, which consisted of a conveying unit, a system control unit, an ultrasonic sensor, and a deposition collecting dish, was designed and developed. The system could precisely move an ultrasonic sensor above a pesticide deposition collecting dish to measure the nozzle flow distribution. A sensor sleeve with a PVC tube was designed for the ultrasonic sensor to limit its beam angle in order to measure the liquid level in the small troughs. System performance tests were conducted to verify the designed functions and measurement accuracy. A commercial spray nozzle was also used to measure its flow distribution. The test results showed that the relative error on volume measurement was less than 7.27% when the liquid volume was 2 mL in trough, while the error was less than 4.52% when the liquid volume was 4 mL or more. The developed system was also used to evaluate the flow distribution of a commercial nozzle. It was able to provide the shape and the spraying width of the flow distribution accurately. PMID:26501288

  16. Two-Dimensional Automatic Measurement for Nozzle Flow Distribution Using Improved Ultrasonic Sensor

    PubMed Central

    Zhai, Changyuan; Zhao, Chunjiang; Wang, Xiu; Wang, Ning; Zou, Wei; Li, Wei

    2015-01-01

    Spray deposition and distribution are affected by many factors, one of which is nozzle flow distribution. A two-dimensional automatic measurement system, which consisted of a conveying unit, a system control unit, an ultrasonic sensor, and a deposition collecting dish, was designed and developed. The system could precisely move an ultrasonic sensor above a pesticide deposition collecting dish to measure the nozzle flow distribution. A sensor sleeve with a PVC tube was designed for the ultrasonic sensor to limit its beam angle in order to measure the liquid level in the small troughs. System performance tests were conducted to verify the designed functions and measurement accuracy. A commercial spray nozzle was also used to measure its flow distribution. The test results showed that the relative error on volume measurement was less than 7.27% when the liquid volume was 2 mL in trough, while the error was less than 4.52% when the liquid volume was 4 mL or more. The developed system was also used to evaluate the flow distribution of a commercial nozzle. It was able to provide the shape and the spraying width of the flow distribution accurately. PMID:26501288

  17. Optical Air Flow Measurements for Flight Tests and Flight Testing Optical Air Flow Meters

    NASA Technical Reports Server (NTRS)

    Jentink, Henk W.; Bogue, Rodney K.

    2005-01-01

    Optical air flow measurements can support the testing of aircraft and can be instrumental to in-flight investigations of the atmosphere or atmospheric phenomena. Furthermore, optical air flow meters potentially contribute as avionics systems to flight safety and as air data systems. The qualification of these instruments for the flight environment is where we encounter the systems in flight testing. An overview is presented of different optical air flow measurement techniques applied in flight and what can be achieved with the techniques for flight test purposes is reviewed. All in-flight optical airflow velocity measurements use light scattering. Light is scattered on both air molecules and aerosols entrained in the air. Basic principles of making optical measurements in flight, some basic optical concepts, electronic concepts, optoelectronic interfaces, and some atmospheric processes associated with natural aerosols are reviewed. Safety aspects in applying the technique are shortly addressed. The different applications of the technique are listed and some typical examples are presented. Recently NASA acquired new data on mountain rotors, mountain induced turbulence, with the ACLAIM system. Rotor position was identified using the lidar system and the potentially hazardous air flow profile was monitored by the ACLAIM system.

  18. Three Phase Probabilistic Load Flow in Radial Distribution Networks

    SciTech Connect

    Melhorn, Alexander C; Dimitrovski, Aleksandar D; Tomsovic, Kevin L

    2012-01-01

    Probabilistic load flow is a helpful tool in accounting for inconsistent or unknown loads and generation. This is especially true with the push for renewable generation and demand response. This paper proposes an improved version of the probabilistic load flow solution for balanced distribution systems and takes the next step by applying it to unbalanced three phase systems. It is validated by comparing the solutions to that obtained by Monte Carlo simulation. The proposed method provides an accurate and practical way for finding the solution to the stochastic problems occurring in power distribution system analysis today.

  19. Distributed measurement of flow rate in conduits using heated fiber optic distributed temperature sensing

    NASA Astrophysics Data System (ADS)

    Sánchez, Raúl; Zubelzu, Sergio; Rodríguez-Sinobas, Leonor; Juana, Luis

    2016-04-01

    In some cases flow varies along conduits, such as in irrigated land drainage pipes and channels, irrigation laterals and others. Detailed knowledge of flow rate along the conduit makes possible analytical evaluation of water distribution and collection systems performance. Flow rate can change continuously in some systems, like in drainage pipes and channels, or abruptly, like in conduits bifurcations or emitter insertions. A heat pulse along the conduit makes possible to get flow rate from continuity and heat balance equations. Due to the great value of specific heat of water, temperature changes along conduit are smaller than the noise that involves the measurement process. This work presents a methodology that, dealing with the noise of distributed temperature measurements, leads to flow rate determination along pressurized pipes or open channel flows.

  20. Distribution of melt during Poiseuille flow of partially molten rocks

    NASA Astrophysics Data System (ADS)

    Quintanilla-Terminel, Alejandra; Dillman, Amanda; Kohlstedt, David

    2016-04-01

    The mechanisms of melt extraction from the Earth's partially molten mantle are a key factor in the chemical and physical evolution of our planet and therefore are the topic of intense research. Since such processes cannot be observed directly, most of our understanding of the dynamics of partially molten rock relies on numerical models. Laboratory experiments are important for testing the validity of models at scales that we can observe. We designed a set of experiments to investigate the role of viscous anisotropy on melt segregation in partially molten rocks through Poiseuille flow. Partially molten rock samples composed of forsterite plus a few percent melt of different composition (anorthite, albite or lithium silicate) were prepared from high-purity nano-powders and taken to T = 1300oC at P = 0.1 MPa. The melt composition was varied in order to vary its viscosity. The partially molten samples were then extruded through a channel of circular cross section under a fixed pressure gradient. Different extrusion assemblies and consequently different flow geometries were explored. The melt distribution in the channel was subsequently mapped using image analysis on backscattered electron microscopy images and energy dispersive x-ray spectroscopy maps. In all experiments, melt segregates from the center toward the outer radius of the channel with the melt fraction at the outer radius increasing to at least twice that at the center. Furthermore, melt enriched areas are also observed in the center of the channel. The shape of the melt distribution depends on the extrusion geometry and on the melt viscosity. The segregation of melt toward the outer radius of the channel is consistent with the base-state melt segregation as predicted by viscous anisotropy theory developed by Takei and Holtzman (2009) and Takei and Katz (2014). However, the melt distribution profiles observed in our experiments have steeper gradients than the base-state melt segregation profiles described

  1. Liquid flow and distribution in unsaturated porous media

    NASA Technical Reports Server (NTRS)

    Alexander, J. Iwan

    2004-01-01

    Flow and transport in permeable or porous media and microchannels occurs in a variety of situations in micro- and reduced-gravity environments, many of them associated with environmental control and life support systems. While the role of gravity is limited, due to the typically small size scales associated permeable media, gravity, at the very least, affects the overall disposition of fluid in a macroscopic system. This presentation will discuss examples where the absence of gravity affects flow and phase distribution in selected examples of unsaturated flow and transport of heat and mass in porous media and microchannels that are pertinent to spacecraft systems.

  2. Distributed allocation of mobile sensing swarms in gyre flows

    NASA Astrophysics Data System (ADS)

    Mallory, K.; Hsieh, M. A.; Forgoston, E.; Schwartz, I. B.

    2013-09-01

    We address the synthesis of distributed control policies to enable a swarm of homogeneous mobile sensors to maintain a desired spatial distribution in a geophysical flow environment, or workspace. In this article, we assume the mobile sensors (or robots) have a "map" of the environment denoting the locations of the Lagrangian coherent structures or LCS boundaries. Using this information, we design agent-level hybrid control policies that leverage the surrounding fluid dynamics and inherent environmental noise to enable the team to maintain a desired distribution in the workspace. We discuss the stability properties of the ensemble dynamics of the distributed control policies. Since realistic quasi-geostrophic ocean models predict double-gyre flow solutions, we use a wind-driven multi-gyre flow model to verify the feasibility of the proposed distributed control strategy and compare the proposed control strategy with a baseline deterministic allocation strategy. Lastly, we validate the control strategy using actual flow data obtained by our coherent structure experimental testbed.

  3. Variable parameter McCarthy-Muskingum flow transport model for compound channels accounting for distributed non-uniform lateral flow

    NASA Astrophysics Data System (ADS)

    Swain, Ratnakar; Sahoo, Bhabagrahi

    2015-11-01

    In this study, the fully volume conservative simplified hydrodynamic-based variable parameter McCarthy-Muskingum (VPMM) flow transport model advocated by Perumal and Price in 2013 is extended to exclusively incorporate the distributed non-uniform lateral flow in the routing scheme accounting for compound river channel flows. The revised VPMM formulation is exclusively derived from the combined form of the de Saint-Venant's continuity and momentum equations with the spatiotemporally distributed lateral flow which is solved using the finite difference box scheme. This revised model could address the earlier model limitations of: (i) non-accounting non-uniformly distributed lateral flow, (ii) ignoring floodplain flow, and (iii) non-consideration of catchment dynamics of lateral flow generation restricting its real-time application. The efficacy of the revised formulation is tested to simulate 16 years (1980-1995) river runoff from real-time storm events under scarce morpho-hydrological data conditions in a tropical monsoon-type 48 km Bolani-Gomlai reach of the Brahmani River in eastern India. The spatiotemporally distributed lateral flows generated in real-time is computed by water balance approach accounting for catchment characteristics of normalized network area function, land use land cover classes, and soil textural classes; and hydro-meteorological variables of precipitation, soil moisture, minimum and maximum temperatures, wind speed, relative humidity, and solar radiation. The multiple error measures used in this study and the simulation results reveal that the revised VPMM model has a greater practical utility in estimating the event-based and long-term meso-scale river runoff (both discharge and its stage) at any ungauged site, enhancing its application for real-time flood estimation.

  4. A thermal distribution function for relativistic magnetically insulated electron flows

    SciTech Connect

    Desjarlais, M.P.; Sudan, R.N.

    1986-05-01

    A distribution function is presented that may be used to study the effects of finite temperature on the equilibrium and stability properties of magnetically insulated electron flows. This distribution function has the useful property that it generates the thoroughly studied class of constant Q = ..omega../sup 2//sub p//..cap omega../sup 2/ equilibria in its zero-temperature limit. Analytic solutions are given for the general, constant Q, zero-temperature equilibria.

  5. Electron concentration distribution in a glow discharge in air flow

    NASA Astrophysics Data System (ADS)

    Mukhamedzianov, R. B.; Gaisin, F. M.; Sabitov, R. A.

    1989-04-01

    Electron concentration distributions in a glow discharge in longitudinal and vortex air flows are determined from the attenuation of the electromagnetic wave passing through the plasma using microwave probes. An analysis of the distribution curves obtained indicates that electron concentration decreases in the direction of the anode. This can be explained by charge diffusion toward the chamber walls and electron recombination and sticking within the discharge.

  6. 46 CFR 162.018-7 - Flow rating tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 6 2010-10-01 2010-10-01 false Flow rating tests. 162.018-7 Section 162.018-7 Shipping...: SPECIFICATIONS AND APPROVAL ENGINEERING EQUIPMENT Safety Relief Valves, Liquefied Compressed Gas § 162.018-7 Flow rating tests. (a) Flow rating of valves shall be conducted in accordance with UG-131 of section VIII...

  7. Goodness of fit tests for generalized gamma distribution

    NASA Astrophysics Data System (ADS)

    Karadaǧ, Özge; Aktaş, Serpil

    2016-06-01

    Gamma distribution is used to model the right skewed data. The goodness of fit tests determine how well the data fit to the underlying distribution. This paper compares the performances of goodness of fit tests for generalized gamma distribution. Kolmogrov Smirnov, Cramer-von Mises and Anderson-Darling tests are considered for testing the goodness of fit between the distribution of sample data and generalized gamma distribution under some different parametric scenarios.

  8. Influence of pressure distribution on flow field temperature reconstruction.

    PubMed

    Chen, Yun-yun; Song, Yang; Li, Zhen-hua; He, An-zhi

    2011-05-20

    This research proposes an issue that has previously been omitted in flow field temperature reconstruction by optical computerized tomography (OCT). To prove that it is not reasonable to always assume an isobaric process occurs when OCT is adopted to obtain the temperature distributions of flow fields, a propane-air flame and an argon arc plasma are chosen as two practical examples for experiment. In addition, the measurement of the refractive index is achieved by moiré deflection tomography. The results indicate that the influence of pressure distribution on temperature reconstruction is a universal phenomenon for various flow fields. Hence, the condition that can be introduced to estimate when an isobaric process can no longer be assumed is presented. In addition, an equation is offered to describe the temperature reconstruction imprecision that is caused by using the supposed pressure instead of the practical pressure. PMID:21614105

  9. Distribution of Thermally Activated Plastic Events in a Flowing Glass

    NASA Astrophysics Data System (ADS)

    Rodney, David; Schuh, Christopher

    2009-06-01

    The potential energy landscape of a flowing metallic glass is revealed using the activation-relaxation technique. For a two-dimensional Lennard-Jones system initially deformed into a steady-state condition through quasistatic shear, the distribution of activation energies is shown to contain a large fraction of low-energy barriers, consistent with a highly nonequilibrium flow state. The distribution of plastic strains has a fundamentally different shape than that obtained during quasistatic simulations, exhibiting a peak at finite strain and, after elastic unloading, a nonzero mean plastic strain that evidences a polarization of the flow state. No significant correlation is found between the activation energy of a plastic event and its associated plastic strain.

  10. Mathematical modelling of flow distribution in the human cardiovascular system

    NASA Technical Reports Server (NTRS)

    Sud, V. K.; Srinivasan, R. S.; Charles, J. B.; Bungo, M. W.

    1992-01-01

    The paper presents a detailed model of the entire human cardiovascular system which aims to study the changes in flow distribution caused by external stimuli, changes in internal parameters, or other factors. The arterial-venous network is represented by 325 interconnected elastic segments. The mathematical description of each segment is based on equations of hydrodynamics and those of stress/strain relationships in elastic materials. Appropriate input functions provide for the pumping of blood by the heart through the system. The analysis employs the finite-element technique which can accommodate any prescribed boundary conditions. Values of model parameters are from available data on physical and rheological properties of blood and blood vessels. As a representative example, simulation results on changes in flow distribution with changes in the elastic properties of blood vessels are discussed. They indicate that the errors in the calculated overall flow rates are not significant even in the extreme case of arteries and veins behaving as rigid tubes.

  11. Distributed Power Flow Control: Distributed Power Flow Control using Smart Wires for Energy Routing

    SciTech Connect

    2012-04-24

    GENI Project: Smart Wire Grid is developing a solution for controlling power flow within the electric grid to better manage unused and overall transmission capacity. The 300,000 miles of high-voltage transmission line in the U.S. today are congested and inefficient, with only around 50% of all transmission capacity utilized at any given time. Increased consumer demand should be met in part with more efficient and an economical power flow. Smart Wire Grid’s devices clamp onto existing transmission lines and control the flow of power within—much like how internet routers help allocate bandwidth throughout the web. Smart wires could support greater use of renewable energy by providing more consistent control over how that energy is routed within the grid on a real-time basis. This would lessen the concerns surrounding the grid’s inability to effectively store intermittent energy from renewables for later use.

  12. Numerical Modelling of Vegetation Flow Interaction: the Wienfluss Test Case

    NASA Astrophysics Data System (ADS)

    Wilson, C.; Yagci, O.; Rauch, H.; Stoesser, T.

    2003-04-01

    We apply a three-dimensional computational fluid dynamics code based on a finite-volume discretisation to a 170m test reach of the a river in Vienna. One of the primary aims of this paper is to test various methods for representing the flow resistance of natural vegetation. The two approaches considered vary in complexity and could be practically implemented and applied within 2D and 3D flood modelling tools. The first approach uses empirical relationships derived from the laboratory data and modifies the existing friction term in the momentum equations. While the second approach introduces a drag related sink term in addition to the bed friction term. The roughness closure models considered do not modify the turbulence model (in this case the k-e model) and hence do not require re-calibration for each application. The test reach is straight and comprises an asymmetrical compound channel that is vegetated on the floodplain by willows and unvegetated within the main channel. The development of the willows has been monitored over a four year period and plant parameters which characterise the dimensions of individual trees and their distribution have been quantified. Further, streamwise velocity data of high-spatial resolution has been collected at one cross-section for a series of flood events. The performance of each approach is quantified in terms of its ability to reproduce the streamwise velocity distribution in a partially vegetated channel. Different parameter tests are conducted to allow the sensitivity of the computed velocities against mesh resolution, and other important plant properties to be examined. For both flow resistance approaches, reasonable agreement is found between the measured and computed floodplain velocities.

  13. LPT. EBOR (TAN646) reactor vessel, flow distribution tank. Outlet nozzle ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LPT. EBOR (TAN-646) reactor vessel, flow distribution tank. Outlet nozzle on side of vessel will be connected to coolant duct. Photographer: Lowin. Date: January 20, 1965. INEEL negative no. 65-237 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

  14. Mean and fluctuating flow measurements in axisymmetric supersonic boundary layer flow subjected to distributed adverse pressure gradients

    NASA Technical Reports Server (NTRS)

    Gootzait, E.; Childs, M. E.

    1974-01-01

    Measurements have been made of the mean flow properties and turbulent fluctuations in adiabatic turbulent boundary layer flows subjected to distributed adverse pressure gradients. In the freestream region upstream of the adverse pressure gradient the Mach number was 3.86, the unit Reynolds number 5.3 million per foot. The boundary layer developed on the wall of an axisymmetric nozzle and straight test section. In order to avoid the effects of streamwise surface curvature the adverse pressure gradients at the test section wall were induced by contoured centerbodies mounted on the wind tunnel centerline. The flow under study simulated that which might be found in an axially symmetric engine inlet of a supersonic aircraft.

  15. Tests Of Shear-Flow Model For Acoustic Impedance

    NASA Technical Reports Server (NTRS)

    Parrot, Tony L.; Watson, Willie R.; Jones, Michael G.

    1992-01-01

    Tests described in report conducted to validate two-dimensional shear-flow analytical model for determination of acoustic impedance of acoustic liner in grazing-incidence, grazing-flow environment by use of infinite-waveguide method. Tests successful for both upstream and downstream propagations. Work has potential for utility in testing of engine ducts in commercial aircraft.

  16. Concentration distribution of contaminant transport in wetland flows

    NASA Astrophysics Data System (ADS)

    Wu, Zi; Fu, Xudong; Wang, Guangqian

    2015-06-01

    Study on contaminant transport in wetland flows is of fundamental importance. Recent investigation on scalar transport in laminar tube flows (Wu and Chen, 2014. J. Fluid Mech., 740: 196-213.) indicates that the vertical concentration difference in wetland flows may be remarkable for a very long time, which cannot be captured by the extensively applied one-dimensional Taylor dispersion model. To understand detailed information for the vertical distribution of contaminant in wetland flows, for the first time, the present paper deduces an analytical solution for the multi-dimensional concentration distribution by the method of mean concentration expansion. The solution is verified by both our analytical and numerical results. Representing the effects of vegetation in wetlands, the unique dimensionless parameter α can cause the longitudinal contraction of the contaminant cloud and the change of the shape of the concentration contours. By these complicated effects, it is shown unexpectedly that the maximum vertical concentration difference remains nearly unaffected, although its longitudinal position may change. Thus the slow-decaying transient effect (Wu and Chen, 2014. J. Hydrol., 519: 1974-1984.) is shown also apply to the process of contaminant transport in wetland flows.

  17. Analysis of Flow Angularity Repeatability Tests in the NTF

    NASA Technical Reports Server (NTRS)

    Hemsch, Michael J.

    2006-01-01

    An extensive data base of flow angularity repeatability measurements from four NTF check standard model tests is analyzed for statistical consistency and to characterize the results for prediction of angle-of-attack uncertainty for customer tests. A procedure for quality assurance for flow angularity measurements during customer tests is also presented. The efficacy of the procedure is tested using results from a customer test.

  18. Moisture Distribution and Flow During Drying of Wood and Fiber

    SciTech Connect

    Zink-Sharp, Audrey; Hanna, Robert B.

    2001-12-28

    New understanding, theories, and techniques for moisture flow and distribution were developed in this research on wood and wood fiber. Improved understanding of the mechanisms of flake drying has been provided. Observations of flake drying and drying rate curves revealed that rate of moisture loss consisted of two falling rate periods and no constant rate drying period was observed. Convective heat transfer controls the first period, and bound water diffusion controls the second period. Influence of lower drying temperatures on bending properties of wood flakes was investigated. Drying temperature was found to have a significant influence on bending stiffness and strength. A worksheet for calculation of the energy required to dry a single strandboard flake was developed but has not been tested in an industrial setting yet. A more complete understanding of anisotropic transverse shrinkage of wood is proposed based on test results and statistical analysis. A simplified mod el of a wood cell's cross-section was drawn for calculating differential transverse shrinkage. The model utilizes cell wall thickness and microfibrillar packing density and orientation. In spite of some phenomena of cell wall structure not yet understood completely, the results might explain anisotropic transverse shrinkage to a major extent. Boundary layer theory was found useful for evaluating external moisture resistance during drying. Simulated moisture gradients were quire comparable to the actual gradients in dried wood. A mathematical procedure for determining diffusion and surface emission coefficients was also developed. Thermal conductivity models of wood derived from its anatomical structure were created and tested against experimental values. Model estimations provide insights into changes in heat transfer parameters during drying. Two new techniques for measuring moisture gradients created in wood during drying were developed. A new technique that utilizes optical properties of cobalt

  19. Some Effects of Air Flow on the Penetration and Distribution of Oil Sprays

    NASA Technical Reports Server (NTRS)

    Rothrock, A M; Beardsley, E G

    1929-01-01

    Tests were made to determine the effects of air flow on the characteristics of fuel sprays from fuel injection valves. Curves and photographs are presented showing the airflow throughout the chamber and the effects of the air flow on the fuel spray characteristics. It was found that the moving air had little effect on the spray penetration except with the 0.006 inch orifice. The moving air did, however, affect the oil particles on the outside of the spray cone. After spray cut-off, the air flow rapidly distributed the atomized fuel throughout the spray chamber.

  20. Regenerator flow distribution by means of a burner

    SciTech Connect

    Tsai, Y.W.

    1983-03-01

    In a regenerative furnace of the type used for melting glass, employment of a gas stream (preferably from a high-velocity burner) in the plenum of the regenerator controls the gas flow distribution within the regenerator. The employment of this auxiliary burner makes the heating of the packing more uniform, minimizes localized overheating of the packing, and improves regenerator efficiency. This flow control device can be added readily to an existing operating furnace with no disruption of operation and at relatively low cost.

  1. Pitot-pressure distributions of the flow field of a delta-wing orbiter

    NASA Technical Reports Server (NTRS)

    Cleary, J. W.

    1972-01-01

    Pitot pressure distributions of the flow field of a 0.0075-scale model of a typical delta wing shuttle orbiter are presented. Results are given for the windward and leeward sides on centerline in the angle-of-attack plane from wind tunnel tests conducted in air. Distributions are shown for three axial stations X/L = .35, .60, and .98 and for angles of attack from 0 to 60 deg. The tests were made at a Mach number of 7.4 and for Reynolds numbers based on body length from 1,500,000 to 9,000,000. The windward distributions at the two survey stations forward of the body boat tail demonstrate the compressive aspects of the flow from the shock wave to the body. Conversely, the distributions at the aft station display an expansion of the flow that is attributed to body boat tail. On the lee side, results are given at low angles of attack that illustrate the complicating aspects of the canopy on the flow field, while results are given to show the effects of flow separation at high angles of attack.

  2. 10 CFR 431.198 - Enforcement testing for distribution transformers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Enforcement testing for distribution transformers. 431.198... COMMERCIAL AND INDUSTRIAL EQUIPMENT Distribution Transformers Compliance and Enforcement § 431.198 Enforcement testing for distribution transformers. (a) Test notice. Upon receiving information in...

  3. Catchment travel time distributions and water flow in soils

    NASA Astrophysics Data System (ADS)

    Rinaldo, A.; Beven, K. J.; Bertuzzo, E.; Nicotina, L.; Davies, J.; Fiori, A.; Russo, D.; Botter, G.

    2011-07-01

    Many details about the flow of water in soils in a hillslope are unknowable given current technologies. One way of learning about the bulk effects of water velocity distributions on hillslopes is through the use of tracers. However, this paper will demonstrate that the interpretation of tracer information needs to become more sophisticated. The paper reviews, and complements with mathematical arguments and specific examples, theory and practice of the distribution(s) of the times water particles injected through rainfall spend traveling through a catchment up to a control section (i.e., "catchment" travel times). The relevance of the work is perceived to lie in the importance of the characterization of travel time distributions as fundamental descriptors of catchment water storage, flow pathway heterogeneity, sources of water in a catchment, and the chemistry of water flows through the control section. The paper aims to correct some common misconceptions used in analyses of travel time distributions. In particular, it stresses the conceptual and practical differences between the travel time distribution conditional on a given injection time (needed for rainfall-runoff transformations) and that conditional on a given sampling time at the outlet (as provided by isotopic dating techniques or tracer measurements), jointly with the differences of both with the residence time distributions of water particles in storage within the catchment at any time. These differences are defined precisely here, either through the results of different models or theoretically by using an extension of a classic theorem of dynamic controls. Specifically, we address different model results to highlight the features of travel times seen from different assumptions, in this case, exact solutions to a lumped model and numerical solutions of the 3-D flow and transport equations in variably saturated, physically heterogeneous catchment domains. Our results stress the individual characters of the

  4. Footprints of Lagrangian flow structures in Eulerian concentration distributions in periodic mixing flows

    NASA Astrophysics Data System (ADS)

    Speetjens, M. F. M.; Lauret, M.; Nijmeijer, H.; Anderson, P. D.

    2013-05-01

    Transport of passive tracers may be described through the spatio-temporal evolution of Eulerian concentration distributions or via the geometrical composition of the Lagrangian flow structure. The present study seeks to deepen insight into the connection between the Eulerian and Lagrangian perspectives by investigating the role of Lagrangian coherent structures (LCSs) in the Eulerian concentration distributions in time-periodic and spatially-periodic mixing flows. Representation of the Eulerian transport by the mapping method, describing realistic transport problems by distribution matrices, admits a generic analysis based on matrix and graph theory. This reveals that LCSs-and the transport barriers that separate them-leave a distinct “footprint” in the eigenmode spectrum of the distribution matrix and, by proxy, of the underlying Eulerian transport operator. Transport barriers impart a block-diagonal structure upon the mapping matrix, where each block matrix A corresponds with a given LCS. Its kind is reflected in the spectrum of A; higher-order periodicity yields a distinct permutation within A. The composition of the distribution matrix versus the Lagrangian flow structure thus predicted is demonstrated by way of examples. These findings increase fundamental understanding of transport phenomena and have great practical potential for e.g. flow and mixing control.

  5. Endogenic craters on basaltic lava flows - Size frequency distributions

    NASA Technical Reports Server (NTRS)

    Greeley, R.; Gault, D. E.

    1979-01-01

    Circular crater forms, termed collapse depressions, which occur on many basalt flows on the earth have also been detected on the moon and Mars and possibly on Mercury and Io. The admixture of collapse craters with impact craters would affect age determinations of planetary surface units based on impact crater statistics by making them appear anomalously old. In the work described in the present paper, the techniques conventionally used in planetary crater counting were applied to the determination of the size range and size frequency distribution of collapse craters on lava flows in Idaho, California, and New Mexico. Collapse depressions range in size from 3 to 80 m in diameter; their cumulative size distributions are similar to those of small impact craters on the moon.

  6. Study of fractal aperture distribution and flow in fractures

    SciTech Connect

    Kumar, S.; Zimmerman, R.W.; Bodvarsson, G.S.

    1990-01-01

    This study examines the roughness profiles and aperture distributions of fractures and faults by using concepts from fractal geometry. Simple models of flow of fluid in rough fractures are also discussed. A deterministic fractal representation of the roughness profile is presented which is shown to have many distinct advantages over other numerical methods, such as information compression, uniqueness and repeatability of surface simulation, retention of statistical information, and self-similarity over many scales. Also the fractal representation enables an isotropic surface and an aperture distribution to be simulated by examining a measured profile. Saturated fluid flow in fractures is then computed using a combined Navier-Stokes and Darcy equation. 14 refs., 5 figs.

  7. Stokes flow in a pipe with distributed regions of slip

    NASA Astrophysics Data System (ADS)

    Lauga, Eric; Stone, Howard A.

    2002-11-01

    Steady pressure-driven Stokes flow in a circular pipe is investigated analytically in the case where the pipe surface contains periodically distributed transverse regions of zero surface shear stress. One physical motivation for this problem is the recent experimental observation of nanobubbles on smooth hydrophobic surfaces (Ishida et al. (2000) Langmuir vol. 16, Tyrrell and Attard (2001) Phys. Rev. Lett. vol. 87) while a second motivation is the possible presence of bubbles trapped on rough surfaces. The bubbles may provide a zero shear stress boundary condition for the flow and modify considerably the friction generated by the solid boundary. In the spirit of experimental studies probing apparent slip at solid surfaces, the effective slip length of the resulting macroscopic flow is evaluated numerically and asymptotically as a function of the relative width of the no-slip and no-shear stress regions and their distribution along the pipe. Comparison of the model with experimental studies of pressure-driven flow in capillaries and microchannels is made and a possible interpretation of the results is offered which is consistent with a large number of nano-size and micron-size bubbles coating the solid surface. Finally, an explanation for the seemingly paradoxical behavior of the measured slip length increasing with system size reported by Watanabe et al. (1999) (J. Fluid Mech. vol. 381) is proposed and the possibility of a shear-dependent effective slip length is suggested.

  8. Blood flow distribution with adrenergic and histaminergic antagonists

    SciTech Connect

    Baker, C.H.; Davis, D.L.; Sutton, E.T.

    1989-03-01

    Superficial fibular nerve stimulation (SFNS) causes increased pre- and post-capillary resistances as well as increased capillary permeability in the dog hind paw. These responses indicate possible adrenergic and histaminergic interactions. The distribution of blood flow between capillaries and arteriovenous anastomoses (AVA) may depend on the relative effects of these neural inputs. Right hind paws of anesthetized heparinized dogs were vascularly and neurally isolated and perfused with controlled pressure. Blood flow distribution was calculated from the venous recovery of 85Sr-labeled microspheres (15 microns). The mean transit times of 131I-albumin and 85Sr-labeled microspheres were calculated. The effects of adrenergic and histaminergic antagonists with and without SFNS were determined. Phentolamine blocked the entire response to SFNS. Prazosin attenuated increases in total and AVA resistance. Yohimbine prevented increased total resistance, attenuated the AVA resistance increase, and revealed a decrease in capillary circuit resistance. Pyrilamine attenuated total resistance increase while SFNS increased capillary and AVA resistances. Metiamide had no effect on blood flow distribution with SFNS. The increase in AVA resistance with SFNS apparently resulted from a combination of alpha 1 and alpha 2 receptor stimulation but not histaminergic effects.

  9. Capillary flow solderability test for printed wiring boards

    SciTech Connect

    Hosking, F.M.; Yost, F.G.; Hernandez, C.L.; Sackinger, S.J.

    1994-04-01

    This report describes a new technique for evaluating capillary flow solderability on printed circuit boards. The test involves the flow of molten solder from a pad onto different-sized conductor lines. It simulates the spreading dynamics of either plated-through-hole (PTH) or surface mount technology (SMT) soldering. A standard procedure has been developed for the test. Preliminary experiments were conducted and the results demonstrate test feasibility. Test procedures and results are presented in this report.

  10. Oscillating flow loss test results in Stirling engine heat exchangers

    NASA Technical Reports Server (NTRS)

    Koester, G.; Howell, S.; Wood, G.; Miller, E.; Gedeon, D.

    1990-01-01

    The results are presented for a test program designed to generate a database of oscillating flow loss information that is applicable to Stirling engine heat exchangers. The tests were performed on heater/cooler tubes of various lengths and entrance/exit configurations, on stacked and sintered screen regenerators of various wire diameters and on Brunswick and Metex random fiber regenerators. The test results were performed over a range of oscillating flow parameters consistent with Stirling engine heat exchanger experience. The tests were performed on the Sunpower oscillating flow loss rig which is based on a variable stroke and variable frequency linear drive motor. In general, the results are presented by comparing the measured oscillating flow losses to the calculated flow losses. The calculated losses are based on the cycle integration of steady flow friction factors and entrance/exit loss coefficients.

  11. Oscillating-flow regenerator test rig

    NASA Technical Reports Server (NTRS)

    Wood, J. G.; Gedeon, D. R.

    1994-01-01

    This report summarizes work performed in setting up and performing tests on a regenerator test rig. An earlier status report presented test results, together with heat transfer correlations, for four regenerator samples (two woven screen samples and two felt metal samples). Lessons learned from this testing led to improvements to the experimental setup, mainly instrumentation as well as to the test procedure. Given funding and time constraints for this project it was decided to complete as much testing as possible while the rig was set up and operational, and to forego final data reduction and analysis until later. Additional testing was performed on several of the previously tested samples as well an on five newly fabricated samples. The following report is a summary of the work performed at OU, with many of the final test results included in raw data form.

  12. High Temperature Ceramic Guide Vane Temperature and Pressure Distribution Calculation for Flow with Cooling Jets

    NASA Technical Reports Server (NTRS)

    Srivastava, Rakesh

    2004-01-01

    A ceramic guide vane has been designed and tested for operation under high temperature. Previous efforts have suggested that some cooling flow may be required to alleviate the high temperatures observed near the trailing edge region. The present report describes briefly a three-dimensional viscous analysis carried out to calculate the temperature and pressure distribution on the blade surface and in the flow path with a jet of cooling air exiting from the suction surface near the trailing edge region. The data for analysis was obtained from Dr. Craig Robinson. The surface temperature and pressure distribution along with a flowfield distribution is shown in the results. The surface distribution is also given in a tabular form at the end of the document.

  13. Laminar flow control leading edge glove flight test article development

    NASA Technical Reports Server (NTRS)

    Pearce, W. E.; Mcnay, D. E.; Thelander, J. A.

    1984-01-01

    A laminar flow control (LFC) flight test article was designed and fabricated to fit into the right leading edge of a JetStar aircraft. The article was designed to attach to the front spar and fill in approx. 70 inches of the leading edge that are normally occupied by the large slipper fuel tank. The outer contour of the test article was constrained to align with an external fairing aft of the front spar which provided a surface pressure distribution over the test region representative of an LFC airfoil. LFC is achieved by applying suction through a finely perforated surface, which removes a small fraction of the boundary layer. The LFC test article has a retractable high lift shield to protect the laminar surface from contamination by airborne debris during takeoff and low altitude operation. The shield is designed to intercept insects and other particles that could otherwise impact the leading edge. Because the shield will intercept freezing rain and ice, a oozing glycol ice protection system is installed on the shield leading edge. In addition to the shield, a liquid freezing point depressant can be sprayed on the back of the shield.

  14. NASA Flight Tests Explore Supersonic Laminar Flow

    NASA Video Gallery

    In partnership with Aerion Corporation of Reno, Nevada, NASA's Dryden Flight Research Center’s tested supersonic airflow over a small experimental airfoil design on its F-15B Test Bed aircraft du...

  15. Altitude Compensating Nozzle Cold Flow Test Results

    NASA Technical Reports Server (NTRS)

    Ruf, J. H.; McDaniels, D. M.

    2002-01-01

    A suite of four altitude compensating nozzle (ACN) concepts were evaluated by NASA MSFC in the Nozzle Test Facility. The ACN concepts were a dual bell, a dual expander, an annular plug nozzle and an expansion deflection nozzle. Two reference bell nozzles were also tested. Axial thrust and nozzle wall static pressures were measured for each nozzle over a wide range of nozzle pressure ratios. The nozzle hardware and test program are described. Sample test results are presented.

  16. Noninvasive blood flow tests in vascular disease.

    PubMed Central

    Steinmetz, O. K.; Cole, C. W.

    1993-01-01

    Noninvasive testing is now routine for assessing vascular conditions. Many noninvasive tests are available for obtaining physiologic and anatomic information that is both precise and reproducible. This paper discusses noninvasive testing with plethysmography, Doppler ultrasonography, and duplex scanning for carotid artery occlusive disease, deep venous thrombosis, and peripheral arterial occlusive disease. Images Figure 2 Figure 3 PMID:8268746

  17. Assessment of the National Transonic Facility for Laminar Flow Testing

    NASA Technical Reports Server (NTRS)

    Crouch, Jeffrey D.; Sutanto, Mary I.; Witkowski, David P.; Watkins, A. Neal; Rivers, Melissa B.; Campbell, Richard L.

    2010-01-01

    A transonic wing, designed to accentuate key transition physics, is tested at cryogenic conditions at the National Transonic Facility at NASA Langley. The collaborative test between Boeing and NASA is aimed at assessing the facility for high-Reynolds number testing of configurations with significant regions of laminar flow. The test shows a unit Reynolds number upper limit of 26 M/ft for achieving natural transition. At higher Reynolds numbers turbulent wedges emanating from the leading edge bypass the natural transition process and destroy the laminar flow. At lower Reynolds numbers, the transition location is well correlated with the Tollmien-Schlichting-wave N-factor. The low-Reynolds number results suggest that the flow quality is acceptable for laminar flow testing if the loss of laminar flow due to bypass transition can be avoided.

  18. Quantification of hepatic flow distribution using particle tracking for patient specific virtual Fontan surgery

    NASA Astrophysics Data System (ADS)

    Yang, Weiguang; Vignon-Clementel, Irene; Troianowski, Guillaume; Shadden, Shawn; Mohhan Reddy, V.; Feinstein, Jeffrey; Marsden, Alison

    2010-11-01

    The Fontan surgery is the third and final stage in a palliative series to treat children with single ventricle heart defects. In the extracardiac Fontan procedure, the inferior vena cava (IVC) is connected to the pulmonary arteries via a tube-shaped Gore-tex graft. Clinical observations have shown that the absence of a hepatic factor, carried in the IVC flow, can cause pulmonary arteriovenous malformations. Although it is clear that hepatic flow distribution is an important determinant of Fontan performance, few studies have quantified its relation to Fontan design. In this study, we virtually implanted three types of grafts (T-junction, offset and Y-graft) into 5 patient specific models of the Glenn (stage 2) anatomy. We then performed 3D time-dependent simulations and systematically compared the IVC flow distribution, energy loss, and pressure levels in different surgical designs. A robustness test is performed to evaluate the sensitivity of hepatic distribution to pulmonary flow split. Results show that the Y-graft design effectively improves the IVC flow distribution, compared to traditional designs and that surgical designs could be customized on a patient-by-patient basis.

  19. Reliability and field testing of distributed strain and temperature sensors

    NASA Astrophysics Data System (ADS)

    Inaudi, Daniele; Glisic, Branko

    2006-03-01

    Distributed fiber optic sensing presents unique features that have no match in conventional sensing techniques. The ability to measure temperatures and strain at thousands of points along a single fiber is particularly interesting for the monitoring of large structures such as pipelines, flow lines, oil wells, dams and dikes. Sensing systems based on Brillouin and Raman scattering have been used for example to detect pipeline leakages, verify pipeline operational parameters, prevent failure of pipelines installed in landslide areas, optimize oil production from wells and detect hot-spots in high-power cables. The measurement instruments have been vastly improved in terms of spatial, temperature and strain resolution, distance range, measurement time, data processing and system cost. Analyzers for Brillouin and Raman scattering are now commercially available and offer reliable operation in field conditions. New application opportunities have however demonstrated that the design and production of sensing cables is a critical element for the success of any distributed sensing instrumentation project. Although standard telecommunication cables can be effectively used for sensing ordinary temperatures, monitoring high and low temperatures or distributed strain present unique challenges that require specific cable designs. This contribution presents three cable designs for high-temperature sensing, strain sensing and combined strain and temperature monitoring as well as the respective testing procedures during production and in the field.

  20. Influence of Gravity on Blood Volume and Flow Distribution

    NASA Technical Reports Server (NTRS)

    Pendergast, D.; Olszowka, A.; Bednarczyk, E.; Shykoff, B.; Farhi, L.

    1999-01-01

    In our previous experiments during NASA Shuttle flights SLS 1 and 2 (9-15 days) and EUROMIR flights (30-90 days) we observed that pulmonary blood flow (cardiac output) was elevated initially, and surprisingly remained elevated for the duration of the flights. Stroke volume increased initially and then decreased, but was still above 1 Gz values. As venous return was constant, the changes in SV were secondary to modulation of heart rate. Mean blood pressure was at or slightly below 1 Gz levels in space, indicating a decrease in total peripheral resistance. It has been suggested that plasma volume is reduced in space, however cardiac output/venous return do not return to 1 Gz levels over the duration of flight. In spite of the increased cardiac output, central venous pressure was not elevated in space. These data suggest that there is a change in the basic relationship between cardiac output and central venous pressure, a persistent "hyperperfusion" and a re-distribution of blood flow and volume during space flight. Increased pulmonary blood flow has been reported to increase diffusing capacity in space, presumably due to the improved homogeneity of ventilation and perfusion. Other studies have suggested that ventilation may be independent of gravity, and perfusion may not be gravity- dependent. No data for the distribution of pulmonary blood volume were available for flight or simulated microgravity. Recent studies have suggested that the pulmonary vascular tree is influenced by sympathetic tone in a manner similar to that of the systemic system. This implies that the pulmonary circulation is dilated during microgravity and that the distribution of blood flow and volume may be influenced more by vascular control than by gravity. The cerebral circulation is influenced by sympathetic tone similarly to that of the systemic and pulmonary circulations; however its effects are modulated by cerebral autoregulation. Thus it is difficult to predict if cerebral perfusion is

  1. Flow generation in a novel centrifugal diffuser test device

    NASA Astrophysics Data System (ADS)

    Vidos, P.

    1983-09-01

    Recognition of the need to develop optimum diffusers for advanced centrifugal compressors, resulted in the design and manufacture of a novel low-speed test facility for centrifugal diffuser testing. The CDTD was designed to allow the flow angle and wall boundary profiles into the test diffuser to be controlled by variable geometry in the flow generator. The present study reports on the design of the flow generator and the analysis of the internal flow using a NASA computer code (MERIDL). First test results are given and are compared with the results of a control volume analysis. The flow angle control technique was found to work effectively but to give somewhat smaller angles (by 4 deg) than were predicted. It was concluded that the information obtained would allow scaling of the device; however, an analysis code was needed which would accept the real physical boundary conditions.

  2. Effects of intraborehole flow on groundwater age distribution

    USGS Publications Warehouse

    Zinn, B.A.; Konikow, L.F.

    2007-01-01

    Environmental tracers are used to estimate groundwater ages and travel times, but the strongly heterogeneous nature of many subsurface environments can cause mixing between waters of highly disparate ages, adding additional complexity to the age-estimation process. Mixing may be exacerbated by the presence of wells because long open intervals or long screens with openings at multiple depths can transport water and solutes rapidly over a large vertical distance. The effect of intraborehole flow on groundwater age was examined numerically using direct age transport simulation coupled with the Multi-Node Well Package of MODFLOW. Ages in a homogeneous, anisotropic aquifer reached a predevelopment steady state possessing strong depth dependence. A nonpumping multi-node well was then introduced in one of three locations within the system. In all three cases, vertical transport along the well resulted in substantial changes in age distributions within the system. After a pumping well was added near the nonpumping multi-node well, ages were further perturbed by a flow reversal in the nonpumping multi-node well. Results indicated that intraborehole flow can substantially alter groundwater ages, but the effects are highly dependent on local or regional flow conditions and may change with time. ?? Springer-Verlag 2007.

  3. Test report light duty utility arm power distribution system (PDS)

    SciTech Connect

    Clark, D.A.

    1996-03-04

    The Light Duty Utility Arm (LDUA) Power Distribution System has completed vendor and post-delivery acceptance testing. The Power Distribution System has been found to be acceptable and is now ready for integration with the overall LDUA system.

  4. Pressure Distribution in Nonuniform Two-Dimensional Flow

    NASA Technical Reports Server (NTRS)

    Schwabe, M.

    1943-01-01

    In an attempt to follow the time rate of change of the processes in turbulent flows by quantitative measurements the measurement of the pressure is often beset with insuperable difficulties for the reason that the speeds and hence the pressures to be measured are often very small. On the other hand, the measurement of very small pressures requires, at least, considerable time, so that the follow-up of periodically varying processes is as goad as impossible. In order to obviate these difficulties a method, suggested by Prof. Prandtl, has been developed by which the pressure distribution is simply determined from the photographic flow picture. This method is described and proved on a worked-out example. It was found that quantitatively very satisfactory results can be achieved.

  5. Separate Flow Nozzle Test Status Meeting

    NASA Technical Reports Server (NTRS)

    Saiyed, Naseem H. (Editor)

    2000-01-01

    NASA Glenn, in partnership with US industry, completed an exhaustive experimental study on jet noise reduction from separate flow nozzle exhaust systems. The study developed a data base on various bypass ratio nozzles, screened quietest configurations and acquired pertinent data for predicting the plume behavior and ultimately its corresponding jet noise. Several exhaust system configurations provided over 2.5 EPNdB jet noise reduction at take-off power. These data were disseminated to US aerospace industry in a conference hosted by NASA GRC whose proceedings are shown in this report.

  6. Flow Simulation of Solid Rocket Motors. 1; Injection Induced Water-Flow Tests from Porous Media

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Yeh, Y. P.; Smith, A. W.; Heaman, J. P.

    1999-01-01

    Prior to selecting a proper porous material for use in simulating the internal port flow of a solid rocket motor (SRM), in cold-flow testing, the flow emerging from porous materials is experimentally investigated. The injection-flow emerging from a porous matrix always exhibits a lumpy velocity profile that is spatially stable and affects the development of the longitudinal port flow. This flow instability, termed pseudoturbulence, is an inherent signature of the porous matrix and is found to generally increase with the wall porosity and with the injection flow rate. Visualization studies further show that the flow from porous walls made from shaving-type material (sintered stainless-steel) exhibits strong recirculation zones that are conspicuously absent in walls made from nodular or spherical material (sintered bronze). Detailed flow visualization observations and hot-film measurements are reported from tests of injection-flow and a coupled cross-flow from different porous wall materials. Based on the experimental data, discussion is provided on the choice of suitable material for SRM model testing while addressing the consequences and shortcomings from such a test.

  7. Test flow disturbances in an expansion tube

    NASA Technical Reports Server (NTRS)

    Paull, A.; Stalker, R. J.

    1992-01-01

    The operation of an expansion tube is investigated theoretically with emphasis on the factors that have limited the utility of the expansion tube in the past. It is shown why the window of steady test conditions is narrow and how this window can be expanded so that these facilities can be used in a variety of hypersonic research. The theoretical predictions are supported by centerline Pitot pressure measurements using air as the test gas.

  8. PATHFINDER: Probing Atmospheric Flows in an Integrated and Distributed Environment

    NASA Technical Reports Server (NTRS)

    Wilhelmson, R. B.; Wojtowicz, D. P.; Shaw, C.; Hagedorn, J.; Koch, S.

    1995-01-01

    PATHFINDER is a software effort to create a flexible, modular, collaborative, and distributed environment for studying atmospheric, astrophysical, and other fluid flows in the evolving networked metacomputer environment of the 1990s. It uses existing software, such as HDF (Hierarchical Data Format), DTM (Data Transfer Mechanism), GEMPAK (General Meteorological Package), AVS, SGI Explorer, and Inventor to provide the researcher with the ability to harness the latest in desktop to teraflop computing. Software modules developed during the project are available in the public domain via anonymous FTP from the National Center for Supercomputing Applications (NCSA). The address is ftp.ncsa.uiuc.edu, and the directory is /SGI/PATHFINDER.

  9. Flight tests of a supersonic natural laminar flow airfoil

    NASA Astrophysics Data System (ADS)

    Frederick, M. A.; Banks, D. W.; Garzon, G. A.; Matisheck, J. R.

    2015-06-01

    A flight test campaign of a supersonic natural laminar flow airfoil has been recently completed. The test surface was an 80 inch (203 cm) chord and 40 inch (102 cm) span article mounted on the centerline store location of an F-15B airplane. The test article was designed with a leading edge sweep of effectively 0° to minimize boundary layer crossflow. The test article surface was coated with an insulating material to avoid significant heat transfer to and from the test article structure to maintain a quasi-adiabatic wall. An aircraft-mounted infrared camera system was used to determine boundary layer transition and the extent of laminar flow. The tests were flown up to Mach 2.0 and chord Reynolds numbers in excess of 30 million. The objectives of the tests were to determine the extent of laminar flow at high Reynolds numbers and to determine the sensitivity of the flow to disturbances. Both discrete (trip dots) and 2D disturbances (forward-facing steps) were tested. A series of oblique shocks, of yet unknown origin, appeared on the surface, which generated sufficient crossflow to affect transition. Despite the unwanted crossflow, the airfoil performed well. The results indicate that the sensitivity of the flow to the disturbances, which can translate into manufacturing tolerances, was similar to that of subsonic natural laminar flow wings.

  10. Flight Tests of a Supersonic Natural Laminar Flow Airfoil

    NASA Technical Reports Server (NTRS)

    Frederick, Michael A.; Banks, Daniel W.; Garzon, G. A.; Matisheck, J. R.

    2015-01-01

    A flight-test campaign of a supersonic natural laminar flow airfoil has been recently completed. The test surface was an 80-inch (203 cm) chord and 40-inch (102 cm) span article mounted on the centerline store location of an F-15B airplane (McDonnell Douglas Corporation, now The Boeing Company, Chicago, Illinois). The test article was designed with a leading edge sweep of effectively 0 deg to minimize boundary layer crossflow. The test article surface was coated with an insulating material to avoid significant heat transfer to and from the test article structure to maintain a quasi-adiabatic wall. An aircraft-mounted infrared camera system was used to determine boundary layer transition and the extent of laminar flow. The tests were flown up to Mach 2.0 and chord Reynolds numbers in excess of 30 million. The objectives of the tests were to determine the extent of laminar flow at high Reynolds numbers and to determine the sensitivity of the flow to disturbances. Both discrete (trip dots) and 2-D disturbances (forward-facing steps) were tested. A series of oblique shocks, of yet unknown origin, appeared on the surface, which generated sufficient crossflow to affect transition. Despite the unwanted crossflow, the airfoil performed well. The results indicate the sensitivity of the flow to the disturbances, which can translate into manufacturing tolerances, were similar to that of subsonic natural laminar flow wings.

  11. Probabilistic Vulnerability Assessment Based on Power Flow and Voltage Distribution

    SciTech Connect

    Ma, Jian; Huang, Zhenyu; Wong, Pak C.; Ferryman, Thomas A.

    2010-04-30

    Risk assessment of large scale power systems has been an important problem in power system reliability study. Probabilistic technique provides a powerful tool to solve the task. In this paper, we present the results of a study on probabilistic vulnerability assessment on WECC system. Cumulant based expansion method is applied to obtain the probabilistic distribution function (PDF) and cumulative distribution function (CDF) of power flows on transmission lines and voltage. Overall risk index based on the system vulnerability analysis is calculated using the WECC system. The simulation results based on WECC system is used to demonstrate the effectiveness of the method. The methodology can be applied to the risk analysis on large scale power systems.

  12. Emulsification in turbulent flow: 3. Daughter drop-size distribution.

    PubMed

    Tcholakova, Slavka; Vankova, Nina; Denkov, Nikolai D; Danner, Thomas

    2007-06-15

    Systematic set of experiments is performed to clarify the effects of several factors on the size distribution of the daughter drops, which are formed as a result of drop breakage during emulsification in turbulent flow. The effects of oil viscosity, etaD, interfacial tension, sigma, and rate of energy dissipation in the turbulent flow, epsilon, are studied. As starting oil-water premixes we use emulsions containing monodisperse oil drops, which have been generated by membrane emulsification. By passing these premixes through a narrow-gap homogenizer, working in turbulent regime of emulsification, we monitor the changes in the drop-size distribution with the emulsification time. The experimental data are analyzed by using a new numerical procedure, which is based on the assumption (supported by the experimental data) that the probability for formation of daughter drops with diameter smaller than the maximum diameter of the stable drops, ddistribution of these daughter drops depend strongly on the viscosity of the dispersed phase. Different scaling laws are found to describe the experimental results for the oils of low and high viscosity. The obtained results for the daughter drop-size distribution are in a reasonably good agreement with the experimental results reported by other authors. In contrast, the comparison with several basic model functions, proposed in the literature, does not show good agreement and the possible reasons are discussed. The proposed numerical procedure allows us to describe accurately the evolution of all main characteristics of the drop-size distribution during emulsification, such as the number and volume averaged diameters, and the distributive and cumulative functions by

  13. Flow tests of the Willis Hulin well

    SciTech Connect

    Randolph, P.L.; Hayden, C.G.; Rogers, L.A.

    1992-02-01

    The Hulin well was tested between 20,100 and 20,700 feet down in layers of brine-saturated clean sand with occasional intervening layers of shale. The characteristics of the brine and gas were determined in this interval and an initial determination of the reservoir properties were made.

  14. Flow Quality Studies of the NASA Glenn Research Center Icing Research Tunnel Circuit (1995 Tests)

    NASA Technical Reports Server (NTRS)

    Arrington, E. Allen; Kee-Bowling, Bonnie A.; Gonsalez, Jose C.

    2000-01-01

    The purpose of conducting the flow-field surveys described in this report was to more fully document the flow quality in several areas of the tunnel circuit in the NASA Glenn Research Center Icing Research Tunnel. The results from these surveys provide insight into areas of the tunnel that were known to exhibit poor flow quality characteristics and provide data that will be useful to the design of flow quality improvements and a new heat exchanger for the facility. An instrumented traversing mechanism was used to survey the flow field at several large cross sections of the tunnel loop over the entire speed range of the facility. Flow-field data were collected at five stations in the tunnel loop, including downstream of the fan drive motor housing, upstream and downstream of the heat exchanger, and upstream and downstream of the spraybars located in the settling chamber upstream of the test section. The data collected during these surveys greatly expanded the data base describing the flow quality in each of these areas. The new data matched closely the flow quality trends recorded from earlier tests. Data collected downstream of the heat exchanger and in the settling chamber showed how the configuration of the folded heat exchanger affected the pressure, velocity, and flow angle distributions in these areas. Smoke flow visualization was also used to qualitatively study the flow field in an area downstream of the drive fan and in the settling chamber/contraction section.

  15. Flight Tests of a Supersonic Natural Laminar Flow Airfoil

    NASA Technical Reports Server (NTRS)

    Frederick, M. A.; Banks, D. W.; Garzon, G. A.; Matisheck, J. R.

    2014-01-01

    A flight test campaign of a supersonic natural laminar flow airfoil has been recently completed. The test surface was an 80-inch (203 cm) chord and 40-inch (102 cm) span article mounted on the centerline store location of an F-15B airplane. The wing was designed with a leading edge sweep of effectively 0 deg to minimize boundary layer crossflow. The test article surface was coated with an insulating material to avoid significant heat transfer to and from the test article structure to maintain a quasi-adiabatic wall. An aircraft-mounted infrared camera system was used to determine boundary layer transition and the extent of laminar flow. The tests were flown up to Mach 2.0 and chord Reynolds numbers in excess of 30 million. The objectives of the tests were to determine the extent of laminar flow at high Reynolds numbers and to determine the sensitivity of the flow to disturbances. Both discrete (trip dots) and 2-D disturbances (forward-facing steps) were tested. A series of oblique shocks, of yet unknown origin, appeared on the surface, which generated sufficient crossflow to affect transition. Despite the unwanted crossflow, the airfoil performed well. The results indicate the sensitivity of the flow to the disturbances, which can translate into manufacturing tolerances, were similar to that of subsonic natural laminar flow wings.

  16. The Forced Flow Flame-Spreading Test (FFFT)

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Forced Flow Flame-Spreading Test was designed to study flame spreading over solid fuels when air is flowing at a low speed concurrent airflows, some materials are more flammable in microgravity than earth. 1.5 cm flame in microgravity that melts a polyethylene cylinder into a liquid ball.

  17. Flow-test device fits into restricted access passages

    NASA Technical Reports Server (NTRS)

    Fitzgerald, J. J.; Oberschmidt, M.; Rosenbaum, B. J.

    1967-01-01

    Test device using a mandrel with a collapsible linkage assembly enables a fluid flow sensor to be properly positioned in a restricted passage by external manipulation. This device is applicable to the combustion chamber of a rocket motor.

  18. How is flow experienced and by whom? Testing flow among occupations.

    PubMed

    Llorens, Susana; Salanova, Marisa; Rodríguez, Alma M

    2013-04-01

    The aims of this paper are to test (1) the factorial structure of the frequency of flow experience at work; (2) the flow analysis model in work settings by differentiating the frequency of flow and the frequency of its prerequisites; and (3) whether there are significant differences in the frequency of flow experience depending on the occupation. A retrospective study among 957 employees (474 tile workers and 483 secondary school teachers) using multigroup confirmatory factorial analyses and multiple analyses of variance suggested that on the basis of the flow analysis model in work settings, (1) the frequency of flow experience has a two-factor structure (enjoyment and absorption); (2) the frequency of flow experience at work is produced when both challenge and skills are high and balanced; and (3) secondary school teachers experience flow more frequently than tile workers. PMID:22674654

  19. Measurement of countercurrent phase separation and distribution in a two-dimensional test section

    SciTech Connect

    Bukhari, K M; Lahey, Jr, R T

    1984-01-01

    The degree of phase separation that occurs in the core of a pressurized water reactor (PWR) during various postulated accidents is an important consideration for studying the course of events during such accidents. The dependence of countercurrent phase separation and distribution phenomena on flow quality, mass flux and system geometry was studied experimentally in a two-dimensional (2-D) test section. A two-phase (air/water) mixture flowed upwards and single-phase water flowed downward along one side of the test section. This countercurrent flow configuration was intended to simulate the so-called chimney effect in the diabatic JAERI 2-D experiments in Japan. A large air/water loop used with a 91.44 cm x 91.44 cm x 1.27 cm test section to study phase separation and distribution effects. A traversing single beam gamma-densitometer was used to measure the chordal average void fractions at several elevations along the test section. Cross-plots between various flow conditions and geometries were made. An error analysis giving the total error in the void fraction measurements was also performed. High speed photographs were also made of the flow structure, to provide information on flow regimes. The photographic records and the void fraction and hydraulic inflow/outflow data are presented in a form suitable for the assessment of advanced generation computer codes (e.g., TRAC).

  20. Time series power flow analysis for distribution connected PV generation.

    SciTech Connect

    Broderick, Robert Joseph; Quiroz, Jimmy Edward; Ellis, Abraham; Reno, Matthew J.; Smith, Jeff; Dugan, Roger

    2013-01-01

    Distributed photovoltaic (PV) projects must go through an interconnection study process before connecting to the distribution grid. These studies are intended to identify the likely impacts and mitigation alternatives. In the majority of the cases, system impacts can be ruled out or mitigation can be identified without an involved study, through a screening process or a simple supplemental review study. For some proposed projects, expensive and time-consuming interconnection studies are required. The challenges to performing the studies are twofold. First, every study scenario is potentially unique, as the studies are often highly specific to the amount of PV generation capacity that varies greatly from feeder to feeder and is often unevenly distributed along the same feeder. This can cause location-specific impacts and mitigations. The second challenge is the inherent variability in PV power output which can interact with feeder operation in complex ways, by affecting the operation of voltage regulation and protection devices. The typical simulation tools and methods in use today for distribution system planning are often not adequate to accurately assess these potential impacts. This report demonstrates how quasi-static time series (QSTS) simulation and high time-resolution data can be used to assess the potential impacts in a more comprehensive manner. The QSTS simulations are applied to a set of sample feeders with high PV deployment to illustrate the usefulness of the approach. The report describes methods that can help determine how PV affects distribution system operations. The simulation results are focused on enhancing the understanding of the underlying technical issues. The examples also highlight the steps needed to perform QSTS simulation and describe the data needed to drive the simulations. The goal of this report is to make the methodology of time series power flow analysis readily accessible to utilities and others responsible for evaluating

  1. Distributed acoustic receptivity in laminar flow control configurations

    NASA Technical Reports Server (NTRS)

    Choudhari, Meelan

    1992-01-01

    A model problem related to distributed receptivity to free-stream acoustic waves in laminar flow control (LFC) configurations is studied, within the Orr-Sommerfield framework, by a suitable extension of the Goldstein-Ruban theory for receptivity due to localized disturbances on the airfoil surface. The results, thus, complement the earlier work on the receptivity produced by local variations in the surface suction and/or surface admittance. In particular, we show that the cumulative effect of the distributed receptivity can be substantially larger than that of a single, isolated suction strip or slot. Furthermore, even if the receptivity is spread out over very large distances, the most effective contributions come from a relatively short region in vicinity of the lower branch of the neutral stability curve. The length scale of this region is intermediate to that of the mean of these two length scales. Finally, it is found that the receptivity is effectively dominated by a narrow band of Fourier components from the wall-suction and admittance distributions, roughly corresponding to a detuning of less than ten percent with respect to the neutral instability wavenumber at the frequency under consideration. The results suggest that the drop-off in receptivity magnitudes away from the resonant wavenumber is nearly independent of the frequency parameter.

  2. 10 CFR 431.198 - Enforcement testing for distribution transformers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Enforcement testing for distribution transformers. 431.198 Section 431.198 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Distribution Transformers Compliance and Enforcement § 431.198 Enforcement testing for...

  3. The Absolute Differential Area Technique for Testing Distributional Normality.

    ERIC Educational Resources Information Center

    Bennett, Richard P.

    The results of a study of find alternative techniques for testing distributional normality are presented. A group of statistical techniques--some established and some new--were compared using empirical techniques. One new technique which appears to have higher power than the Lilliefors test was subjected to a better definition. Distributions under…

  4. Investigation of the velocity distribution in the flow of a journal bearing model

    NASA Astrophysics Data System (ADS)

    Nobis, Matthias; Reinke, Peter; Schmidt, Marcus; Riedel, Marco; Redlich, Marcel

    2014-03-01

    In many previous studies the main focus was put on the pressure distribution in the lubricating gap. Due to the limited space in the gap an investigation of the velocity distribution is very difficult or rather impossible. Based on the geometrical shapes of a real journal bearing, a bearing model test rig with an increased relative gap width has been developed. Thus, it is possible to detect the distribution of the flow speed within the gap by using a Laser Doppler Velocimeter (LDV). The comparability of the flow to the flow in a real journal bearing is ensured by observing the Reynolds similarity. Due to a targeted eccentricity in the system and the circumferential groove over 180°, there is in connection with the outlet hole in the rotating shaft a permanent change in the outflow conditions. The consequence is a periodically varying system pressure with effects to the pressure and volumetric flow rate at the inlet and outlet. The velocity measurements with a triggered LDV are done by considering these transient boundary conditions at the system boundaries. In this paper the experimental setup, the expiration of the investigations and some exemplary results are presented. Attendant to the experiment, numerical simulations are carried out and the results are compared with the experimental data.

  5. Flammable gas interlock spoolpiece flow response test plan and procedure

    SciTech Connect

    Schneider, T.C., Fluor Daniel Hanford

    1997-02-13

    The purpose of this test plan and procedure is to test the Whittaker electrochemical cell and the Sierra Monitor Corp. flammable gas monitors in a simulated field flow configuration. The sensors are used on the Rotary Mode Core Sampling (RMCS) Flammable Gas Interlock (FGI), to detect flammable gases, including hydrogen and teminate the core sampling activity at a predetermined concentration level.

  6. Snow distribution and heat flow in the taiga

    SciTech Connect

    Sturm, M. )

    1992-05-01

    The trees of the taiga intercept falling snow and cause it to become distributed in an uneven fashion. Around aspen and birch, cone-shaped accumulations form. Beneath large spruce trees, the snow cover is depleted, forming a bowl-shaped depression called a tree well. Small spruce trees become covered with snow, creating cavities that funnel cold air to the snow/ground interface. The depletion of snow under large spruce trees results in greater heat loss from the ground. A finite difference model suggests that heat flow from tree wells can be more than twice that of undisturbed snow. In forested watersheds, this increase can be a significant percentage of the total winter energy exchange.

  7. Influence of flow rate on aerosol particle size distributions from pressurized and breath-actuated inhalers.

    PubMed

    Smith, K J; Chan, H K; Brown, K F

    1998-01-01

    Particle size distribution of delivered aerosols and the total mass of drug delivered from the inhaler are important determinants of pulmonary deposition and response to inhalation therapy. Inhalation flow rate may vary between patients and from dose to dose. The Andersen Sampler (AS) cascade impactor operated at flow rates of 30 and 55 L/min and the Marple-Miller Impactor (MMI) operated at flow rates of 30, 55, and 80 L/min were used in this study to investigate the influence of airflow rate on the particle size distributions of inhalation products. Total mass of drug delivered from the inhaler, fine particle mass, fine particle fraction, percentage of nonrespirable particles, and amount of formulation retained within the inhaler were determined by ultraviolet spectrophotometry for several commercial bronchodilator products purchased in the marketplace, including a pressurized metered-dose inhaler (pMDI), breath-actuated pressurized inhaler (BAMDI), and three dry powder inhalers (DPIs), two containing salbutamol sulphate and the other containing terbutaline sulphate. Varying the flow rate through the cascade impactor produced no significant change in performance of the pressurized inhalers. Increasing the flow rate produced a greater mass of drug delivered and an increase in respirable particle mass and fraction from all DPIs tested. PMID:10346666

  8. Columbia University flow instability experimental program: Volume 3. Single tube parallel flow tests

    SciTech Connect

    Dougherty, T.; Maciuca, C.; McAssey, E.V. Jr.; Reddy, D.G.; Yang, B.W.

    1990-06-01

    The coolant in the Savannah River Site (SRS) production nuclear reactor assemblies is circulated as a subcooled liquid under normal operating conditions. This coolant is evenly distributed throughout multiple annular flow channels with a uniform pressure profile across each coolant flow channel. During the postulated Loss of Coolant Accident (LOCA), which is initiated by a hypothetical guillotine pipe break, the coolant flow through the reactor assemblies is significantly reduced. The flow reduction and accompanying power reduction (after shutdown is initiated) occur in the first 1--2 seconds of the LOCA. This portion of the LOCA is referred to as the Flow Instability phase. A series of down flow experiments have been conducted on three different size single tubes. The objective of these experiments was to determine the effect of a parallel flow path on the occurrence of flow instability. In all cases, it has been shown that the point of flow instability (OFI) determined under controlled flow operation does not change when operating in a controlled pressure drop mode (parallel path operation).

  9. Analytical flow/thermal modeling of combustion gas flows in Redesigned Solid Rocket Motor test joints

    NASA Technical Reports Server (NTRS)

    Woods, G. H.; Knox, E. C.; Pond, J. E.; Bacchus, D. L.; Hengel, J. E.

    1992-01-01

    A one-dimensional analytical tool, TOPAZ (Transient One-dimensional Pipe flow AnalyZer), was used to model the flow characteristics of hot combustion gases through Redesigned Solid Rocket Motor (RSRM) joints and to compute the resultant material surface temperatures and o-ring seal erosion of the joints. The capabilities of the analytical tool were validated with test data during the Seventy Pound Charge (SPC) motor test program. The predicted RSRM joint thermal response to ignition transients was compared with test data for full-scale motor tests. The one-dimensional analyzer is found to be an effective tool for simulating combustion gas flows in RSRM joints and for predicting flow and thermal properties.

  10. ac power control in the Core Flow Test Loop

    SciTech Connect

    McDonald, D.W.

    1980-01-01

    This work represents a status report on a development effort to design an ac power controller for the Core Flow Test Loop. The Core Flow Test Loop will be an engineering test facility which will simulate the thermal environment of a gas-cooled fast-breeder reactor. The problems and limitations of using sinusoidal ac power to simulate the power generated within a nuclear reactor are addressed. The transformer-thyristor configuration chosen for the Core Flow Test Loop power supply is presented. The initial considerations, design, and analysis of a closed-loop controller prototype are detailed. The design is then analyzed for improved performance possibilities and failure modes are investigated at length. A summary of the work completed to date and a proposed outline for continued development completes the report.

  11. Distribution Pattern of Terrestrial Heat Flow in Bohai Bay Basin, North China

    NASA Astrophysics Data System (ADS)

    Wang, L.; Gong, Y.; Liu, S.; Li, C.; Li, H.

    2004-12-01

    New temperature data from wells in Bohai bay basin increasing associated with the enhancement of oil and gas exploration there provides more reliable information about studying on Terrestrial heat flow pattern. Based on the data from 88 systematic continuous temperature logging curves and more than 1000 well test temperature data, along with the corresponding thermo-physical parameters of rock samples, here we determined 53 heat flow data and estimated other 172 according to thermal resistance method, then the distribution Pattern of heat flow in Bohai Bay basin is presented. Heat flow in Bohai bay basin is relatively large than those in the surrounding mountain areas. For instance, heat flow of Yanshan, north of the basin, is only low as 25 ~ 54 mW/m2, and less than 50 mW/m2 for Taihang mountain to the west, the average heat flow of Luxi Uplift is about 54 mW/m2. Crustal thickness of regions outside the basin to the west and north approximating to 36~44km, apparently is larger than that of basin, which maybe accounts for the high heat flow in Bohai bay basin. Those regions of relatively thin crust within the basin are of middle-high heat flow. Heat flow in such depressions as the Lower Liaohe, Bozhong, Jiyang and Yongqing area northeast of Jizhong Depression, together with Bohai offshore, for example, are all larger than 64 mW/m2, and even high as 70 mW/m2 for some regions with mantle upwelling. Low heat flow appears in those areas with relatively thick crust. For instance, heat flow in Linqing Depression, southwest margin of Jizhong Depression and southern Huanghua Depression, are all less than 64 mW/m2, even less than 60 mW/m2 for those areas with mantle downwelling. Heat flow pattern in Bohai Bay basin is negative correlation with crustal thickness, for those regions with relatively crustal thinning, heat derived from the deep earth is more due to the large lithospheric extension, resulting in the high heat flow; while for those with crustal thickening, heat

  12. Computational strategies for three-dimensional flow simulations on distributed computer systems

    NASA Technical Reports Server (NTRS)

    Sankar, Lakshmi N.; Weed, Richard A.

    1995-01-01

    This research effort is directed towards an examination of issues involved in porting large computational fluid dynamics codes in use within the industry to a distributed computing environment. This effort addresses strategies for implementing the distributed computing in a device independent fashion and load balancing. A flow solver called TEAM presently in use at Lockheed Aeronautical Systems Company was acquired to start this effort. The following tasks were completed: (1) The TEAM code was ported to a number of distributed computing platforms including a cluster of HP workstations located in the School of Aerospace Engineering at Georgia Tech; a cluster of DEC Alpha Workstations in the Graphics visualization lab located at Georgia Tech; a cluster of SGI workstations located at NASA Ames Research Center; and an IBM SP-2 system located at NASA ARC. (2) A number of communication strategies were implemented. Specifically, the manager-worker strategy and the worker-worker strategy were tested. (3) A variety of load balancing strategies were investigated. Specifically, the static load balancing, task queue balancing and the Crutchfield algorithm were coded and evaluated. (4) The classical explicit Runge-Kutta scheme in the TEAM solver was replaced with an LU implicit scheme. And (5) the implicit TEAM-PVM solver was extensively validated through studies of unsteady transonic flow over an F-5 wing, undergoing combined bending and torsional motion. These investigations are documented in extensive detail in the dissertation, 'Computational Strategies for Three-Dimensional Flow Simulations on Distributed Computing Systems', enclosed as an appendix.

  13. Testing the instream flow method in trout streams

    SciTech Connect

    Studley, T.K.; Railsback, S.F.; Asce, M.

    1995-12-31

    Pacific Gas and Electric Company`s (PG&E) Department of Research and Development and co-sponsors are fieldtesting the Instream Flow Incremental Methodology (IFIM) at a number of trout stream study sites. Fish populations, flows, and other variables were measured for an eight-year baseline period. Three levels of increasingly sophisticated predictions of population response to increased flows were made. The flow increases have been implemented and additional data are being collected to test the predictions. The baseline data and prediction analyses indicate that (1) using different habitat suitability criteria produces substantially different predictions of how populations respond to flow changes, (2) overlaps in habitat used by trout species can lead to misleading predictions of a population`s response to flow changes, and (3) factors other than habitat during summer low flows can limit trout populations (these include spawning habitat, high flows, stream channel characteristics, and stream temperature). Comprehensive field studies are expensive, but are more likely to result in instream flows that provide a cost-effective tradeoff between power and fisheries values.

  14. Flow tests of the Gladys McCall well

    SciTech Connect

    Randolph, P.L.; Hayden, C.G.; Rogers, L.A. )

    1992-04-01

    This report pulls together the data from all of the geopressured-geothermal field research conducted at the Gladys McCall well. The well produced geopressured brine containing dissolved natural gas from the Lower Miocene sands at a depth of 15,150 to 16,650 feet. More than 25 million barrels of brine and 727 million standard cubic feet of natural gas were produced in a series of flow tests between December 1982 and October 1987 at various brine flow rates up to 28,000 barrels per day. Initial short-term flow tests for the Number 9 Sand found the permeability to be 67 to 85 md (millidarcies) for a brine volume of 85 to 170 million barrels. Initial short-term flow tests for the Number 8 Sand found a permeability of 113 to 132 md for a reservoir volume of 430 to 550 million barrels of brine. The long-term flow and buildup test of the Number 8 Sand found that the high-permeability reservoir connected to the wellbore (measured by the short-term flow test) was connected to a much larger, low-permeability reservoir. Numerical simulation of the flow and buildup tests required this large connected reservoir to have a volume of about 8 billion barrels (two cubic miles of reservoir rock) with effective permeabilities in the range of 0.2 to 20 md. Calcium carbonate scale formation in the well tubing and separator equipment was a problem. During the first 2 years of production, scale formation was prevented in the surface equipment by injection of an inhibitor upstream of the choke. Starting in 1985, scale formation in the production tubing was successfully prevented by injecting inhibitor pills'' directly into the reservoir. Corrosion and/or erosion of surface piping and equipment, as well as disposal well tubing, was also significant.

  15. Hanford Tank Farms Waste Certification Flow Loop Test Plan

    SciTech Connect

    Bamberger, Judith A.; Meyer, Perry A.; Scott, Paul A.; Adkins, Harold E.; Wells, Beric E.; Blanchard, Jeremy; Denslow, Kayte M.; Greenwood, Margaret S.; Morgen, Gerald P.; Burns, Carolyn A.; Bontha, Jagannadha R.

    2010-01-01

    A future requirement of Hanford Tank Farm operations will involve transfer of wastes from double shell tanks to the Waste Treatment Plant. As the U.S. Department of Energy contractor for Tank Farm Operations, Washington River Protection Solutions anticipates the need to certify that waste transfers comply with contractual requirements. This test plan describes the approach for evaluating several instruments that have potential to detect the onset of flow stratification and critical suspension velocity. The testing will be conducted in an existing pipe loop in Pacific Northwest National Laboratory’s facility that is being modified to accommodate the testing of instruments over a range of simulated waste properties and flow conditions. The testing phases, test matrix and types of simulants needed and the range of testing conditions required to evaluate the instruments are described

  16. Effect of relative velocity distribution on efficiency and exit flow of centrifugal impellers

    NASA Astrophysics Data System (ADS)

    Mishina, H.; Nishida, H.

    1983-03-01

    A quasi-three-dimensional flow analysis proposed by Senoo and Nakase (1972) is applied in order to estimate the relative velocity distribution within a centrifugal impeller, assuming that the flow is both isentropic and inviscid. The relationship between relative velocity distribution, impeller efficiency, and meridional exit flow is experimentally investigated for the case of shrouded impellers having various relative velocity distributions. Analytical results are used to establish design criteria for the relative velocity distribution of centrifugal impellers.

  17. Flow-Log Analysis for Hydraulic Characterization of Selected Test Wells at the Indian Point Energy Center, Buchanan, New York

    USGS Publications Warehouse

    Williams, John H.

    2008-01-01

    Flow logs from 24 test wells were analyzed as part of the hydraulic characterization of the metamorphosed and fractured carbonate bedrock at the Indian Point Energy Center in Buchanan, New York. The flow logs were analyzed along with caliper, optical- and acoustic-televiewer, and fluid-resistivity and temperature logs to determine the character and distribution of fracture-flow zones and estimate their transmissivities and hydraulic heads. Many flow zones were associated with subhorizontal to shallow-dipping fractured zones, southeast-dipping bedding fractures, northwest-dipping conjugate fractures, or combinations of bedding and conjugate fractures. Flow-log analysis generally provided reasonable first-order estimates of flow-zone transmissivity and head differences compared with the results of conventional hydraulic-test analysis and measurements. Selected results of an aquifer test and a tracer test provided corroborating information in support of the flow-log analysis.

  18. A modification to vertical distribution of tidal flow Reynolds stress in shallow Sea

    NASA Astrophysics Data System (ADS)

    Ni, Zhi-hui; Song, Zhi-yao; Zhang, Xu-jin; Wu, Li-chun; Yi, Jing

    2012-09-01

    Tidal flow is a periodic movement of unsteady and non-uniform, which has acceleration and deceleration process obviously, especially in coastal shallow waters. Many researches show that vertical distribution of tidal flow Reynolds stress deviated from linear distribution. The parabolic distribution of the tidal flow Reynolds stress was proposed by Song et al. (2009). Although the model fills better with field observations and indoor experimental data, it has the lower truncated series expansion of tidal flow Reynolds stress, and the description of the distribution is not very comprehensive. By introducing the motion equation of tidal flow and improving the parabolic distribution established by Song et al. (2009), the cubic distribution of the tidal flow Reynolds stress is proposed. The cubic distribution is verified well by field data (Bowden and Fairbairn, 1952; Bowden et al., 1959; Rippeth et al., 2002) and experimental data (Anwar and Atkins, 1980), is consistent with the numerical model results of Kuo et al. (1996), and is compared with the parabolic distribution of the tidal flow Reynolds stress. It is shown that this cubic distribution is not only better than the parabolic distribution, but also can better reflect the basic features of Reynolds stress deviating from linear distribution downward with the tidal flow acceleration and upward with the tidal flow deceleration, for the foundation of further study on the velocity profile of tidal flow.

  19. Ground vibration test of the laminar flow control JStar airplane

    NASA Technical Reports Server (NTRS)

    Kehoe, M. W.; Cazier, F. W., Jr.; Ellison, J. F.

    1985-01-01

    A ground vibration test was conducted on a Lockheed JetStar airplane that had been modified for the purpose of conducting laminar flow control experiments. The test was performed prior to initial flight flutter tests. Both sine-dwell and single-point-random excitation methods were used. The data presented include frequency response functions and a comparison of mode frequencies and mode shapes from both methods.

  20. Experiments of Flow Field Influenced by Vegetation Distribution on Floodplain

    NASA Astrophysics Data System (ADS)

    Li, Jin-Fu; Wang, Shun-Chang; Chen, Su-Chin

    2015-04-01

    The vegetation on floodplain can block river flow, raise flood level, and scour riverbed downstream the vegetation region. However, it can also protect the dike, reduce flood velocity, and increase the stability of channel. This experiment analyzed the relationship between vegetation distribution and flow field. We designed three vegetation arrangement pattern of unilateral vegetation, unilateral interval vegetation and no vegetation, respectively. The unilateral vegetation was defined as a 4.9 m length and 0.5 m width with vegetative area in one side of the experiment flume. The unilateral interval vegetation was defined as the same dimension of vegetative area but inserted 2 gaps with 1 m interval, and the vegetative area was separated into 3 blocks. The model of a single plant was assembled with stem and frond. The stem was a woody cylinder with 10 cm height and 2.2 cm in diameter. The other part was plastic frond with 10 cm in height. The flume was 20 m length, 1 m width and 0.7 m height with 2 kinds of bed slopes in 0.001 and 0.002, and 3 different discharges in 0.2 m3/s, 0.145 m3/s and 0.0855 m3/s. The velocity was measured by 2-D electromagnetic velocimeter (ACM2-R2). In addition, water depth was measured by Vernier calipers. The velocity distribution showed that the current were divided into two parts. In the part of inside vegetation area, water level uplifted when flow entering the vegetation area, and it declined until the current leaving vegetation area. Compared with the current in the other half part of flume, the magnitudes of uplift were about 50% in both case of unilateral vegetation and unilateral interval vegetation. Downstream the vegetation area edge, the water level dropped immediately and violently. The water depth was shallower than that in the other half non-vegetation part, and the decline magnitude were 48% and 39% in cases of unilateral vegetation and unilateral interval vegetation, respectively. To explain this phenomenon, we measured

  1. Flow distribution in parallel connected manifolds for evacuated tubular solar collectors

    NASA Astrophysics Data System (ADS)

    McPhedran, R. C.; Mackey, D. J. M.; McKenzie, D. R.; Collins, R. E.

    A model is presented for predicting the flow distribution in solar collector manifolds in which risers are connected in parallel between headers. Both frictional and Bernoulli effects are considered. The distributions resulting from flow in the manifold in which header streams are parallel and opposed are calculated and compared with experiment. Parallel flow gives a more uniform distribution. The outlet header is found to be more critical in balancing the flow distribution than the inlet header. Conditions under which thermosiphon effects are important and flow reversal in risers may occur are discussed with reference to experiment.

  2. Influence of impactor operating flow rate on particle size distribution of four jet nebulizers.

    PubMed

    Zhou, Yue; Brasel, Trevor L; Kracko, Dean; Cheng, Yung-Sung; Ahuja, Amitkumar; Norenberg, Jeffrey P; Kelly, H William

    2007-01-01

    When a nebulizer is evaluated by the Andersen Cascade Impactor (ACI), the flow rate is generally maintained at 28.3 L/min, as recommended by the manufacturer. However, the nebulizer flow rate that a patient inhales is only around 18 L/min. Because the drive flow of a nebulizer is approximately 6-8 L/min, the nebulized drug is mixed with outside air when delivered. Evaluating impactor performance at the 28.3 L/min flow rate is less than ideal because an additional 10 L/min of outside air is mixed with the drug, thereby affecting the drug size distribution and dose before inhalation and deposition in the human lung. In this study we operated the ACI at an 18.0 L/min flow rate to test whether the effect of the changing ambient humidity was being exaggerated by the 28.3 L/min flow rate. The study was carried out at three different relative humidity levels and two different impactor flow rates with four commercially available nebulizers. The mass median aerodynamic diameter (MMAD) and the geometric standard deviation (GSD) of the droplets were found to increase when the impactor was operated at a flow rate of 18 L/min compared to that of 28.3 L/min. The higher MMAD and GSD could cause the patient to inhale less of the drug than expected if the nebulizer was evaluated by the ACI at the operating flow rate of 28.3 L/min. PMID:17763140

  3. An experimental study of a self-confined flow with ring-vorticity distribution. Ph.D. Thesis. Final Report

    NASA Technical Reports Server (NTRS)

    Lin, K. M.; Moore, F. K.

    1976-01-01

    A new form of self-confined flow was investigated in which a recirculation zone forms away from any solid boundary. An inviscid flow analysis indicated that in a purely meridional axisymmetric flow a stationary, spherical, self-confined region should occur in the center of a streamlined divergent-convergent enlargement zone. The spherical confinement region would be at rest and at constant pressure. Experimental investigations were carried out in a specially built test apparatus to establish the desired confined flow. The streamlined divergent-convergent interior shape of the test section was fabricated according to the theoretical calculation for a particular streamline. The required inlet vorticity distribution was generated by producing a velocity profile with a shaped gauze screen in the straight pipe upstream of the test section. Fluid speed and turbulence intensity were measured with a constant-temperature hot-wire anemometer system. The measured results indicated a very orderly and stable flow field.

  4. Fractional flow in fractured chalk; a flow and tracer test revisited

    NASA Astrophysics Data System (ADS)

    Odling, N. E.; West, L. J.; Hartmann, S.; Kilpatrick, A.

    2013-04-01

    A multi-borehole pumping and tracer test in fractured chalk is revisited and reinterpreted in the light of fractional flow. Pumping test data analyzed using a fractional flow model gives sub-spherical flow dimensions of 2.2-2.4 which are interpreted as due to the partially penetrating nature of the pumped borehole. The fractional flow model offers greater versatility than classical methods for interpreting pumping tests in fractured aquifers but its use has been hampered because the hydraulic parameters derived are hard to interpret. A method is developed to convert apparent transmissivity and storativity (L4-n/T and S2-n) to conventional transmissivity and storativity (L2/T and dimensionless) for the case where flow dimension, 2 < n < 3. These parameters may then be used in further applications, facilitating application of the fractional flow model. In the case illustrated, improved fits to drawdown data are obtained and the resultant transmissivities and storativities are found to be lower by 30% and an order of magnitude respectively, than estimates from classical methods. The revised hydraulic parameters are used in a reinterpretation of a tracer test using an analytical dual porosity model of solute transport incorporating matrix diffusion and modified for fractional flow. Model results show smaller fracture apertures, spacings and dispersivities than those when 2D flow is assumed. The pumping and tracer test results and modeling presented illustrate the importance of recognizing the potential fractional nature of flow generated by partially penetrating boreholes in fractured aquifers in estimating aquifer properties and interpreting tracer breakthrough curves.

  5. [Flow field test on the tangential section of polypropylene tubular membrane module annular gap in rotating linear tangential flow].

    PubMed

    Wang, Chengduan; Chen, Wenmei; Li, Jianming; Jiang, Guangming

    2002-07-01

    A new type of polypropylene tubular membrane apparatus of rotating cross flow was designed to study experimentally the flow field characteristics of the tangential section of the membrane annular gap. The authors designed rotary linear tangential flow tubular membrane separator and its test system for the first time. Through the system, the flow field of rotary linear tangential flow with the advanced Particle Image Velocimetry (PIV) was tested for the first time. A lot of streamlines and vorticity maps of the tangential section of separator in different operation conditions were obtained. The velocity distribution characteristics were analyzed quantitatively: 1. At non-vortex area, no matter how the operation parameters change, the velocity near to rotary tangential flow entrance was higher than the velocity far from entrance at the same radial coordinates. At vortex area, generally the flow velocity of inner vortex was lower than the outer vortex. At the vortex center, the velocity was lowest, the tangential velocity were equal to zero generally. At the vortex center zone, the tangential velocity was less than the axial velocity. 2. Under test operations, the tangential velocity and axial velocity of vortices borders are 1-2 times of average axial velocity of membrane module annular gap. The maximum tangential velocity and axial velocity of ellipse vortices were 2-6 times of average axial velocity of membrane module annular gap. 3. The vortices that are formed on the tangential section, there existed mass transfer between inner and outer parts of fluid. Much fluid of outer vortices got into the inner ones, which was able to prevent membrane tube from particles blocking up very soon. PMID:12371104

  6. Laminar flow test installation in the Boeing Research Wind Tunnel

    NASA Technical Reports Server (NTRS)

    George-Falvy, Dezso

    1990-01-01

    This paper describes the initial wind tunnels tests in the 5- by 8-ft Boeing Research Wind Tunnel of a near full-scale (20-foot chord) swept wing section having laminar flow control (LFC) by slot suction over its first 30 percent chord. The model and associated test apparatus were developed for use as a testbed for LFC-related experimentation in support of preliminary design studies done under contract with the National Aeronautics and Space Administration. This paper contains the description of the model and associated test apparatus as well as the results of the initial test series in which the proper functioning of the test installation was demonstrated and new data were obtained on the sensitivity of suction-controlled laminar flow to surface protuberances in the presence of crossflow due to sweep.

  7. Wind Tunnel Test Results for Gas Flows Inside Axisymmetric Cavities on Cylindric Bodies with Nose Cones

    NASA Technical Reports Server (NTRS)

    Shvets, A. L.; Gilinsky, M.; Blankson, I. M.

    2004-01-01

    Experimental test results of air flow inside and at the cylindrical cavity located on axisymmetric body are presented. These tests were conducted in the wind tunnel A-7 of Institute of Mechanics at Moscow State University. Pressure distribution along the cavities and optical measurements were obtained. Dependence of these characteristics of length of a cavity in the range: L/D = 0.5 - 14 and free stream Mach in the range: M(sub infinity) = 0.6 - 3.0 was determined. Flow structure inside the cavity, cause of flow regime change, separation zones geometry and others were studied. In particular, the flow modes of with open and closed separation zones are determined.

  8. Design verification and cold-flow modeling test report

    SciTech Connect

    Not Available

    1993-07-01

    This report presents a compilation of the following three test reports prepared by TRW for Alaska Industrial Development and Export Authority (AIDEA) as part of the Healy Clean Coal Project, Phase 1 Design of the TRW Combustor and Auxiliary Systems, which is co-sponsored by the Department of Energy under the Clean Coal Technology 3 Program: (1) Design Verification Test Report, dated April 1993, (2) Combustor Cold Flow Model Report, dated August 28, 1992, (3) Coal Feed System Cold Flow Model Report, October 28, 1992. In this compilation, these three reports are included in one volume consisting of three parts, and TRW proprietary information has been excluded.

  9. Univariate and Bivariate Loglinear Models for Discrete Test Score Distributions.

    ERIC Educational Resources Information Center

    Holland, Paul W.; Thayer, Dorothy T.

    2000-01-01

    Applied the theory of exponential families of distributions to the problem of fitting the univariate histograms and discrete bivariate frequency distributions that often arise in the analysis of test scores. Considers efficient computation of the maximum likelihood estimates of the parameters using Newton's Method and computationally efficient…

  10. Distribution of "Compound" and "Simple" Flows in the Deccan Traps (India)

    NASA Astrophysics Data System (ADS)

    Vanderkluysen, L.; Self, S.; Jay, A. E.; Sheth, H. C.; Clarke, A. B.

    2014-12-01

    The Deccan Traps are a dominantly mafic large igneous province (LIP) that, prior to erosion, covered ~1 million km2 of west-central India with lava flows. The type sections of the Western Ghats escarpment, where the Deccan lava pile reaches a maximum reconstructed stratigraphic thickness of ~3400 m, are subdivided into eleven formations defined on chemo-stratigraphic grounds. Earlier work recognized that emplacement of Deccan basalt flows primarily occurs following two main modes: as a stack of meter-sized pāhoehoe toes and lobes, termed "compound" flows; or as inflated sheet lobes tens to hundreds of meters in width and meters to tens of meters in height, previously termed "simple" flows. Initially, the distribution of small lobes and sheet lobes in the Deccan was thought to be controlled by distance from source, but later work suggested the distribution to be mainly controlled along stratigraphic, formational boundaries, with six of the lower formations being composed exclusively of compound flows, and the upper 4-5 formations being wholly built of sheet lobes. This simple stratigraphic subdivision of lava flow morphologies has also been documented in the volcanic architecture of other LIPs, e.g., the Etendeka, the Ethiopian Traps, and in the Faeroe Islands (North Atlantic LIP). Upon examination of eight sections carefully logged along the Western Ghats, this traditional view must be challenged. Where the lower Deccan formations crop out, we found that as much as 65% of the exposed thickness (below the Khandala Formation) is made up of sheet lobes, from 40% in the Bhimashankar Formation to 75% in the Thakurvadi Formation. Near the bottom of the sequence, 25% of the Neral Formation is composed of sheet lobes ≥15 m in thickness. This distribution in lava flow morphology does not seem to be noticeably affected by the inferred distance to the source (based on the location of similar-composition dikes for each formation). Several mechanisms have been proposed to

  11. Fan Noise Source Diagnostic Test: LDV Measured Flow Field Results

    NASA Technical Reports Server (NTRS)

    Podboy, Gary C.; Krupar, Martin J.; Hughes, Christopher E.; Woodward, Richard P.

    2003-01-01

    Results are presented of an experiment conducted to investigate potential sources of noise in the flow developed by two 22-in. diameter turbofan models. The R4 and M5 rotors that were tested were designed to operate at nominal take-off speeds of 12,657 and 14,064 RPMC, respectively. Both fans were tested with a common set of swept stators installed downstream of the rotors. Detailed measurements of the flows generated by the two were made using a laser Doppler velocimeter system. The wake flows generated by the two rotors are illustrated through a series of contour plots. These show that the two wake flows are quite different, especially in the tip region. These data are used to explain some of the differences in the rotor/stator interaction noise generated by the two fan stages. In addition to these wake data, measurements were also made in the R4 rotor blade passages. These results illustrate the tip flow development within the blade passages, its migration downstream, and (at high rotor speeds) its merging with the blade wake of the adjacent (following) blade. Data also depict the variation of this tip flow with tip clearance. Data obtained within the rotor blade passages at high rotational speeds illustrate the variation of the mean shock position across the different blade passages.

  12. Single element injector cold flow testing for STME swirl coaxial injector element design

    NASA Astrophysics Data System (ADS)

    Hulka, J.; Schneider, J. A.

    1993-06-01

    An oxidizer-swirled coaxial element injector is being investigated for application in the Space Transportation Main Engine (STME). Single element cold flow experiments were conducted to provide characterization of the STME injector element for future analysis, design, and optimization. All tests were conducted to quiescent, ambient backpressure conditions. Spray angle, circumferential spray uniformity, dropsize, and dropsize distribution were measured in water-only and water/nitrogen flows. Rupe mixing efficiency was measured using water/sucrose solution flows with a large grid patternator for simple comparative evaluation of mixing. Factorial designs of experiment were used for statistical evaluation of injector geometrical design features and propellant flow conditions on mixing and atomization. Increasing the free swirl angle of the liquid oxidizer had the greatest influence on increasing the mixing efficiency. The addition of gas assistance had the most significant effect on reducing oxidizer droplet size parameters and increasing droplet size distribution. Increasing the oxidizer injection velocity had the greatest influence for reducing oxidizer droplet size parameters and increasing size distribution for non-gas assisted flows. Single element and multi-element subscale hot fire testing are recommended to verify optimized designs before committing to the STME design.

  13. Single element injector cold flow testing for STME swirl coaxial injector element design

    NASA Technical Reports Server (NTRS)

    Hulka, J.; Schneider, J. A.

    1993-01-01

    An oxidizer-swirled coaxial element injector is being investigated for application in the Space Transportation Main Engine (STME). Single element cold flow experiments were conducted to provide characterization of the STME injector element for future analysis, design, and optimization. All tests were conducted to quiescent, ambient backpressure conditions. Spray angle, circumferential spray uniformity, dropsize, and dropsize distribution were measured in water-only and water/nitrogen flows. Rupe mixing efficiency was measured using water/sucrose solution flows with a large grid patternator for simple comparative evaluation of mixing. Factorial designs of experiment were used for statistical evaluation of injector geometrical design features and propellant flow conditions on mixing and atomization. Increasing the free swirl angle of the liquid oxidizer had the greatest influence on increasing the mixing efficiency. The addition of gas assistance had the most significant effect on reducing oxidizer droplet size parameters and increasing droplet size distribution. Increasing the oxidizer injection velocity had the greatest influence for reducing oxidizer droplet size parameters and increasing size distribution for non-gas assisted flows. Single element and multi-element subscale hot fire testing are recommended to verify optimized designs before committing to the STME design.

  14. Flow Visualization of Liquid Hydrogen Line Chilldown Tests

    NASA Technical Reports Server (NTRS)

    Rame, Enrique; Hartwig, Jason W.; McQuillen John B.

    2014-01-01

    We present experimental measurements of wall and fluid temperature during chill-down tests of a warm cryogenic line with liquid hydrogen. Synchronized video and fluid temperature measurements are used to interpret stream temperature profiles versus time. When cold liquid hydrogen starts to flow into the warm line, a sequence of flow regimes, spanning from all-vapor at the outset to bubbly with continuum liquid at the end can be observed at a location far downstream of the cold inlet. In this paper we propose interpretations to the observed flow regimes and fluid temperature histories for two chilldown methods, viz. trickle (i.e. continuous) flow and pulse flow. Calculations of heat flux from the wall to the fluid versus wall temperature indicate the presence of the transition/nucleate boiling regimes only. The present tests, run at typical Reynolds numbers of approx O(10 (exp 5)), are in sharp contrast to similar tests conducted at lower Reynolds numbers where a well-defined film boiling region is observed.

  15. Flow reference method testing and analysis: Field test plan, Texas Utilities Decordova Steam Electric Station

    SciTech Connect

    Lieberman, E.; Werner, A.S.

    1997-05-30

    This report describes the experimental design and test plan for the first of three field tests that the US Environmental Protection Agency (EPA) conducted in 1997 as part of a major study to evaluate potential improvements to Method 2, EPA`s test method for measuring flue gas volumetric flow in stacks. The experimental design involved four test teams taking concurrent in-stack measurements with velocity sensing probes. Seven types of probes were included in the study. Three test matrices were used to gather data for inter-probe and inter-team comparisons and to assess the impact of velocity decline near the stack wall on volumetric flow measurements.

  16. Flow measurements in a centrifugal diffusor test device

    NASA Astrophysics Data System (ADS)

    Vitting, T.

    1985-06-01

    This work sought to verify concepts used in the design of a large scale, low speed, radial cascade wind tunnel which was to be used to investigate flow phenomena in and the performance of vaned radial diffusors. A major contributor to centrifugal compressor efficiency is the performance of the vaned diffusor which closely follows the impeller of the compressor. The purpose of this diffusor is to efficiently convert most of the kinetic energy of the transonic flow entering the vane into pressure. The need for an experimental facility which could simulate adequately, at low cost and in a controlled way, the environment of the centrifugal compressor motivated the development of the Centrifugal Diffusor Test Device (CDTD). It was expected that the generation of a three dimensional flow would provide improved empirical data on annular cascade performance. This measurement program surveyed the axial and circumferential uniformity of the flow at the inlet of a transonic wedge-type blading mounted in the device. Evaluation of the results showed the flow uniformity to be unsatisfactory. Leakage and other small perturbations in the flow field in the swirl generator are believed to be amplified by the basic flow configuration of the device.

  17. EPA flow reference method testing and analysis: Findings report. Appendices

    SciTech Connect

    1999-06-01

    In the summer of 1997, the US Environmental Protection Agency (EPA) conducted a series of week-long field tests at three electric utility sites to evaluate potential improvements to Method 2, EPA`s test method for measuring flue gas volumetric flow in stacks. The findings from that study are presented in document EPA/430-R-99-009a (NTIS Order Number PB99-150286). This document contains 10 appendices for that report.

  18. Mesoscale Simulations of Particulate Flows with Parallel Distributed Lagrange Multiplier Technique

    SciTech Connect

    Kanarska, Y

    2010-03-24

    Fluid particulate flows are common phenomena in nature and industry. Modeling of such flows at micro and macro levels as well establishing relationships between these approaches are needed to understand properties of the particulate matter. We propose a computational technique based on the direct numerical simulation of the particulate flows. The numerical method is based on the distributed Lagrange multiplier technique following the ideas of Glowinski et al. (1999). Each particle is explicitly resolved on an Eulerian grid as a separate domain, using solid volume fractions. The fluid equations are solved through the entire computational domain, however, Lagrange multiplier constrains are applied inside the particle domain such that the fluid within any volume associated with a solid particle moves as an incompressible rigid body. Mutual forces for the fluid-particle interactions are internal to the system. Particles interact with the fluid via fluid dynamic equations, resulting in implicit fluid-rigid-body coupling relations that produce realistic fluid flow around the particles (i.e., no-slip boundary conditions). The particle-particle interactions are implemented using explicit force-displacement interactions for frictional inelastic particles similar to the DEM method of Cundall et al. (1979) with some modifications using a volume of an overlapping region as an input to the contact forces. The method is flexible enough to handle arbitrary particle shapes and size distributions. A parallel implementation of the method is based on the SAMRAI (Structured Adaptive Mesh Refinement Application Infrastructure) library, which allows handling of large amounts of rigid particles and enables local grid refinement. Accuracy and convergence of the presented method has been tested against known solutions for a falling sphere as well as by examining fluid flows through stationary particle beds (periodic and cubic packing). To evaluate code performance and validate particle

  19. Numerical and experimental study on the flow distribution in a water manifold

    NASA Astrophysics Data System (ADS)

    Min, Gwansik; Jong Lee, Pil; Kang, Jong Hoon

    2016-03-01

    This study presents water distribution analysis of the device for spraying cooling water through specific nozzles numerically and experimentally. Numerical analysis was performed using the 3-D incompressible, multi-phase flow model, for different Reynolds numbers of 4 × 105, 8 × 105. Experimental analysis was performed at real-size, under the same conditions. The calculated results and the measured results for the distribution of flow were matched relatively well. The distribution of the nozzle flow depends on the Reynolds number.

  20. CONSTRUCTION AND EVALUATION OF A FLOW TEST STAND

    EPA Science Inventory

    A test stand for the examination of flow monitors in a 3-inch pipe was designed, constructed, and evaluated. The calculations necessary for the proper design are based on empirical data and are described in detail. A statistical analysis was used to estimate the error generated f...

  1. Cotton-Harvester-Flow Simulator for Testing Cotton Yield Monitor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An experimental system was developed to simulate the pneumatic flow arrangement found in picker-type cotton harvesters. The simulation system was designed and constructed for testing a prototype cotton yield monitor developed at Mississippi State University. The simulation system was constructed to ...

  2. Review of Test Facilities for Distributed Energy Resources

    SciTech Connect

    AKHIL,ABBAS ALI; MARNAY,CHRIS; KIPMAN,TIMOTHY

    2003-05-01

    Since initiating research on integration of distributed energy resources (DER) in 1999, the Consortium for Electric Reliability Technology Solutions (CERTS) has been actively assessing and reviewing existing DER test facilities for possible demonstrations of advanced DER system integration concepts. This report is a compendium of information collected by the CERTS team on DER test facilities during this period.

  3. Flow-Field Survey in the Test Region of the SR-71 Aircraft Test Bed Configuration

    NASA Technical Reports Server (NTRS)

    Mizukami, Masashi; Jones, Daniel; Weinstock, Vladimir D.

    2000-01-01

    A flat plate and faired pod have been mounted on a NASA SR-71A aircraft for use as a supersonic flight experiment test bed. A test article can be placed on the flat plate; the pod can contain supporting systems. A series of test flights has been conducted to validate this test bed configuration. Flight speeds to a maximum of Mach 3.0 have been attained. Steady-state sideslip maneuvers to a maximum of 2 deg have been conducted, and the flow field in the test region has been surveyed. Two total-pressure rakes, each with two flow-angle probes, have been placed in the expected vicinity of an experiment. Static-pressure measurements have been made on the flat plate. At subsonic and low supersonic speeds with no sideslip, the flow in the surveyed region is quite uniform. During sideslip maneuvers, localized flow distortions impinge on the test region. Aircraft sideslip does not produce a uniform sidewash over the test region. At speeds faster than Mach 1.5, variable-pressure distortions were observed in the test region. Boundary-layer thickness on the flat plate at the rake was less than 2.1 in. For future experiments, a more focused and detailed flow-field survey than this one would be desirable.

  4. Model-Driven Test Generation of Distributed Systems

    NASA Technical Reports Server (NTRS)

    Easwaran, Arvind; Hall, Brendan; Schweiker, Kevin

    2012-01-01

    This report describes a novel test generation technique for distributed systems. Utilizing formal models and formal verification tools, spe cifically the Symbolic Analysis Laboratory (SAL) tool-suite from SRI, we present techniques to generate concurrent test vectors for distrib uted systems. These are initially explored within an informal test validation context and later extended to achieve full MC/DC coverage of the TTEthernet protocol operating within a system-centric context.

  5. Testing the global flow reconstruction method on coupled chaotic oscillators

    NASA Astrophysics Data System (ADS)

    Plachy, Emese; Kolláth, Zoltán

    2010-03-01

    Irregular behaviour of pulsating variable stars may occur due to low dimensional chaos. To determine the quantitative properties of the dynamics in such systems, we apply a suitable time series analysis, the global flow reconstruction method. The robustness of the reconstruction can be tested through the resultant quantities, like Lyapunov dimension and Fourier frequencies. The latter is specially important as it is directly derivable from the observed light curves. We have performed tests using coupled Rossler oscillators to investigate the possible connection between those quantities. In this paper we present our test results.

  6. Method of Estimating the Incompressible-flow Pressure Distribution of Compressor Blade Sections at Design Angle of Attack

    NASA Technical Reports Server (NTRS)

    Erwin, John R; Yacobi, Laura A

    1953-01-01

    A method was devised for estimating the incompressible-flow pressure distribution over compressor blade sections at design angle of attack. The theoretical incremental velocities due to camber and thickness of the section as an isolated airfoil are assumed proportional to the average passage velocity and are modified by empirically determined interference factors. Comparisons were made between estimated and test pressure distributions of NACA 65-series sections for typical conditions. Good agreement was obtained.

  7. Flow and diffusion of high-stakes test scores

    PubMed Central

    Marder, M.; Bansal, D.

    2009-01-01

    We apply visualization and modeling methods for convective and diffusive flows to public school mathematics test scores from Texas. We obtain plots that show the most likely future and past scores of students, the effects of random processes such as guessing, and the rate at which students appear in and disappear from schools. We show that student outcomes depend strongly upon economic class, and identify the grade levels where flows of different groups diverge most strongly. Changing the effectiveness of instruction in one grade naturally leads to strongly nonlinear effects on student outcomes in subsequent grades. PMID:19805049

  8. Cold Flow Plume Entrainment Test Final Report NTF Test Number 2456

    NASA Technical Reports Server (NTRS)

    Ruf, Joseph H.; McDaniels, David; Mishtawy, Jason; Ramachandran, Narayanan; Hammad, Khaled J.

    2005-01-01

    As part of the Space Shuttle Return to Flight (RTF) program, Marshall Space Flight Center (MSFC) performed computational fluid dynamics (CFD) analysis to define the velocity flowfields around the Shuttle stack at liftoff. These CFD predicted velocity flowfields were used in debris transport analysis (DTA). High speed flows such as plumes induce or 'entrain' mass from the surrounding environment. Previous work had shown that CFD analysis over-predicts plume induced flows. Therefore, the DTA would tend to 1) predict more debris impacts, and 2) the debris velocity (and kinetic energy) of those impacts would be too high. At a November, 2004 peer-review it was recommended that the Liftoff DTA team quantify the uncertainty in the DTA caused by the CFD's over prediction of plume induced flow. To do so, the Liftoff DTA team needed benchmark quality data for plume induced flow to quantify the CFD accuracy and its effect on the DTA. MSFC's Nozzle Test Facility (NTF) conducted the "Nozzle Induced Flows test, P#2456" to obtain experimental data for plume induced flows for nozzle flow exhausting into q quiescent freestream. Planning for the test began in December, 2004 and the experimental data was obtained in February and March of 2005. The funding for this test was provided by MSFC's Space Shuttle Propulsion Systems Integration and Engineering office.

  9. Suppression of secondary flows in a double suction centrifugal pump with different loading distributions

    NASA Astrophysics Data System (ADS)

    Leng, H. F.; Wang, F. J.; Zhang, Z. C.; Yao, Z. F.; Zhou, P. J.

    2013-12-01

    Secondary flow is one of the main reasons for low efficiency in double suction centrifugal pump. In a 3-D inverse design method, the pump blade could be designed by a specified loading distribution to control the flow field in pump. In order to study the influence of loading distribution on secondary flow of a double suction centrifugal pump, the external characteristics and the internal flow field of the pump with three kinds of loading distributions are analysed by using CFD approach. According to the simulation results, it is found that the form of fore-loading distribution at shroud and aft-loading distribution at hub could improve the optimal efficiency and broaden the high efficiency area of the pump. Furthermore, the secondary flow in impeller exit region and volute could be significantly suppressed if the slope of loading distribution curve of shroud is set to be -0.7.

  10. A note on the asymptotic distribution of likelihood ratio tests to test variance components.

    PubMed

    Visscher, Peter M

    2006-08-01

    When using maximum likelihood methods to estimate genetic and environmental components of (co)variance, it is common to test hypotheses using likelihood ratio tests, since such tests have desirable asymptotic properties. In particular, the standard likelihood ratio test statistic is assumed asymptotically to follow a chi2 distribution with degrees of freedom equal to the number of parameters tested. Using the relationship between least squares and maximum likelihood estimators for balanced designs, it is shown why the asymptotic distribution of the likelihood ratio test for variance components does not follow a chi2 distribution with degrees of freedom equal to the number of parameters tested when the null hypothesis is true. Instead, the distribution of the likelihood ratio test is a mixture of chi2 distributions with different degrees of freedom. Implications for testing variance components in twin designs and for quantitative trait loci mapping are discussed. The appropriate distribution of the likelihood ratio test statistic should be used in hypothesis testing and model selection. PMID:16899155

  11. Fluid flow measurements of Test Series A and B for the Small Scale Seal Performance Tests

    SciTech Connect

    Peterson, E.W.; Lagus, P.L.; Lie, K.

    1987-12-01

    The degree of waste isolation achieved by a repository seal system is dependent upon the fluid flow characteristics, or permeability, of the seals. In order to obtain meaningful, site-specific data on the performance of various possible seal system components, a series of in situ experiments called the Small Scale Seal Performance Tests (SSSPT) are being conducted at the Waste Isolation Pilot Plant (WIPP). This report contains the results of gas flow, tracer penetration, and brine flow tests conducted on concrete seals in vertical (Test Series A) and horizontal (Test Series B) configurations. The test objectives were to evaluate the seal performance and to determine if there existed scaling effects which could influence future SSSPT designs. 3 refs., 77 figs.

  12. Measurements of Turbulent Flow Field in Separate Flow Nozzles with Enhanced Mixing Devices - Test Report

    NASA Technical Reports Server (NTRS)

    Bridges, James

    2002-01-01

    As part of the Advanced Subsonic Technology Program, a series of experiments was conducted at NASA Glenn Research Center on the effect of mixing enhancement devices on the aeroacoustic performance of separate flow nozzles. Initial acoustic evaluations of the devices showed that they reduced jet noise significantly, while creating very little thrust loss. The explanation for the improvement required that turbulence measurements, namely single point mean and RMS statistics and two-point spatial correlations, be made to determine the change in the turbulence caused by the mixing enhancement devices that lead to the noise reduction. These measurements were made in the summer of 2000 in a test program called Separate Nozzle Flow Test 2000 (SFNT2K) supported by the Aeropropulsion Research Program at NASA Glenn Research Center. Given the hot high-speed flows representative of a contemporary bypass ratio 5 turbofan engine, unsteady flow field measurements required the use of an optical measurement method. To achieve the spatial correlations, the Particle Image Velocimetry technique was employed, acquiring high-density velocity maps of the flows from which the required statistics could be derived. This was the first successful use of this technique for such flows, and shows the utility of this technique for future experimental programs. The extensive statistics obtained were likewise unique and give great insight into the turbulence which produces noise and how the turbulence can be modified to reduce jet noise.

  13. 3D modelling of the flow of self-compacting concrete with or without steel fibres. Part I: slump flow test

    NASA Astrophysics Data System (ADS)

    Deeb, R.; Kulasegaram, S.; Karihaloo, B. L.

    2014-12-01

    In part I of this two-part paper, a three-dimensional Lagrangian smooth particle hydrodynamics method has been used to model the flow of self-compacting concrete (SCC) with or without short steel fibres in the slump cone test. The constitutive behaviour of this non-Newtonian viscous fluid is described by a Bingham-type model. The 3D simulation of SCC without fibres is focused on the distribution of large aggregates (larger than or equal to 8 mm) during the flow. The simulation of self-compacting high- and ultra-high- performance concrete containing short steel fibres is focused on the distribution of fibres and their orientation during the flow. The simulation results show that the fibres and/or heavier aggregates do not precipitate but remain homogeneously distributed in the mix throughout the flow.

  14. Materials Science Research Rack-1 Fire Suppressant Distribution Test Report

    NASA Technical Reports Server (NTRS)

    Wieland, P. O.

    2002-01-01

    Fire suppressant distribution testing was performed on the Materials Science Research Rack-1 (MSRR-1), a furnace facility payload that will be installed in the U.S. Lab module of the International Space Station. Unlike racks that were tested previously, the MSRR-1 uses the Active Rack Isolation System (ARIS) to reduce vibration on experiments, so the effects of ARIS on fire suppressant distribution were unknown. Two tests were performed to map the distribution of CO2 fire suppressant throughout a mockup of the MSRR-1 designed to have the same component volumes and flowpath restrictions as the flight rack. For the first test, the average maximum CO2 concentration for the rack was 60 percent, achieved within 45 s of discharge initiation, meeting the requirement to reach 50 percent throughout the rack within 1 min. For the second test, one of the experiment mockups was removed to provide a worst-case configuration, and the average maximum CO2 concentration for the rack was 58 percent. Comparing the results of this testing with results from previous testing leads to several general conclusions that can be used to evaluate future racks. The MSRR-1 will meet the requirements for fire suppressant distribution. Primary factors that affect the ability to meet the CO2 distribution requirements are the free air volume in the rack and the total area and distribution of openings in the rack shell. The length of the suppressant flowpath and degree of tortuousness has little correlation with CO2 concentration. The total area of holes in the rack shell could be significantly increased. The free air volume could be significantly increased. To ensure the highest maximum CO2 concentration, the PFE nozzle should be inserted to the stop on the nozzle.

  15. Flap survey test of a combined surface blowing model: Flow measurements at static flow conditions

    NASA Technical Reports Server (NTRS)

    Fukushima, T.

    1978-01-01

    The Combined Surface Blowing (CSB) V/STOL lift/propulsion system consists of a blown flap system which deflects the exhaust from a turbojet engine over a system of flaps deployed at the trailing edge of the wing. Flow measurements consisting of velocity measurements using split film probes and total measure surveys using a miniature Kiel probe were made at control stations along the flap systems at two spanwise stations, the centerline of the nozzle and 60 percent of the nozzle span outboard of the centerline. Surface pressure measurements were made in the wing cove and the upper surface of the first flap element. The test showed a significant flow separation in the wing cove. The extent of the separation is so large that the flow into the first flap takes place only at the leading edge of the flap. The velocity profile measurements indicate that large spanwise (3 dimensional) flow may exist.

  16. 3D Particle image velocimetry test of inner flow in a double blade pump impeller

    NASA Astrophysics Data System (ADS)

    Liu, Houlin; Wang, Kai; Yuan, Shouqi; Tan, Minggao; Wang, Yong; Ru, Weimin

    2012-05-01

    The double blade pump is widely used in sewage treatment industry, however, the research on the internal flow characteristics of the double blade pump with particle image velocimetry (PIV) technology is very little at present. To reveal inner flow characteristics in double blade pump impeller under off-design and design conditions, inner flows in a double blade pump impeller, whose specific speed is 111, are measured under the five off-design conditions and design condition by using 3D PIV test technology. In order to ensure the accuracy of the 3D PIV test, the external trigger synchronization system which makes use of fiber optic and equivalent calibration method are applied. The 3D PIV relative velocity synthesis procedure is compiled by using Visual C++ 2005. Then absolute velocity distribution and relative velocity distribution in the double blade pump impeller are obtained. Test results show that vortex exists in each condition, but the location, size and velocity of vortex core are different. Average absolute velocity value of impeller outlet increases at first, then decreases, and then increases again with increase of flow rate. Again average relative velocity values under 0.4, 0.8, and 1.2 design condition are higher than that under 1.0 design condition, while under 0.6 and 1.4 design condition it is lower. Under low flow rate conditions, radial vectors of absolute velocities at impeller outlet and blade inlet near the pump shaft decrease with increase of flow rate, while that of relative velocities at the suction side near the pump shaft decreases. Radial vectors of absolute velocities and relative velocities change slightly under the two large flow rate conditions. The research results can be applied to instruct the hydraulic optimization design of double blade pumps.

  17. Critical speed in the rat: implications for hindlimb muscle blood flow distribution and fibre recruitment.

    PubMed

    Copp, Steven W; Hirai, Daniel M; Musch, Timothy I; Poole, David C

    2010-12-15

    Critical speed (CS) constitutes an important metabolic and performance demarcator. However, active skeletal muscle blood flow distribution specifically surrounding CS remains unknown. We tested the hypotheses that CS could be accurately determined in the running rat and that measurement of hindlimb inter- and intramuscular blood flow below and above CS would support that the greatest muscle fibre recruitment above, relative to below, CS occurs in the predominantly glycolytic muscles. Seven male Sprague-Dawley rats performed five constant-speed tests to exhaustion at speeds between 95 and 115% of the speed that elicited to determine CS. Subsequent constant-speed tests were performed at speeds incrementally surrounding CS to determine time to exhaustion, V(O2), and hindlimb muscle blood flow distribution. Speed and time to exhaustion conformed to a hyperbolic relationship (r(2) = 0.92 ± 0.03) which corresponded to a linear 1/time function (r(2) = 0.93 ± 0.02) with a CS of 48.6 ± 1.0 m min(-1). Time to exhaustion below CS was ∼ 5× greater (P < 0.01) than that above. Below CS V(O2) stabilized at a submaximal value (58.5 ± 2.5 ml kg(-1) min(-1)) whereas above CS (81.7 ± 2.5 ml kg(-1) min(-1)) increased to (84.0 ± 1.8 ml kg(-1) min(-1), P > 0.05 vs. above CS). The 11 individual muscles or muscle parts that evidenced the greatest blood flow increases above, relative to below, CS were composed of ≥ 69% Type IIb/d/x muscle fibres. Moreover, there was a significant correlation (P < 0.05, r = 0.42) between the increased blood flow above expressed relative to below CS and the percentage Type IIb/d/x fibres found in the individual muscles or muscle parts. These data validate the powerful CS construct in the rat and identify that running above CS, relative to below CS, incurs disproportionate blood flow increases (indicative of recruitment) in predominantly highly glycolytic muscle fibres. PMID:20962004

  18. Laminar heat-transfer distributions on biconics at incidence in hypersonic-hypervelocity flows

    NASA Technical Reports Server (NTRS)

    Miller, C. G., III; Micol, J. R.; Gnoffo, P. A.

    1984-01-01

    Laminar heating distributions were measured at hypersonic-hypervelocity flow conditions on a 1.9-percent-scale model of an aeroassisted vehiclee proposed for missions to a number of planets. This vehicle is a spherically blunted, 12.84/7deg biconic with the fore-cone axis bent upward 7 deg relative to the aft-cone axis to provide selftrim capability. Also tested was a straight biconic (i.e., without nose bend) with the same nose radius and half-angles as the bent-nose biconic. These measurements were made in the Langley Expansion Tube at free-stream velocities from 4.5 to 6.9 km/sec and Mach numbers from 6.0 to 9.0 with helium, nitrogen, air, and carbon dioxide test gases. The range of calculated thermochemical equilibrium normal-shock density ratios for these four test gases was 4 to 19. Angles of attack, referenced to the aft-cone, varied from 0 to 20 deg. Heating distributions predicted with a parabolized Navier-Stokes (PNS) code were compared with measurement for helium and air test gases. Measured windward and leeward heating levels were generally underpredicted by the PNS code for both test gases, and agreement was poorer on the leeward side than on the windward side.

  19. Universal Verification Methodology Based Register Test Automation Flow.

    PubMed

    Woo, Jae Hun; Cho, Yong Kwan; Park, Sun Kyu

    2016-05-01

    In today's SoC design, the number of registers has been increased along with complexity of hardware blocks. Register validation is a time-consuming and error-pron task. Therefore, we need an efficient way to perform verification with less effort in shorter time. In this work, we suggest register test automation flow based UVM (Universal Verification Methodology). UVM provides a standard methodology, called a register model, to facilitate stimulus generation and functional checking of registers. However, it is not easy for designers to create register models for their functional blocks or integrate models in test-bench environment because it requires knowledge of SystemVerilog and UVM libraries. For the creation of register models, many commercial tools support a register model generation from register specification described in IP-XACT, but it is time-consuming to describe register specification in IP-XACT format. For easy creation of register model, we propose spreadsheet-based register template which is translated to IP-XACT description, from which register models can be easily generated using commercial tools. On the other hand, we also automate all the steps involved integrating test-bench and generating test-cases, so that designers may use register model without detailed knowledge of UVM or SystemVerilog. This automation flow involves generating and connecting test-bench components (e.g., driver, checker, bus adaptor, etc.) and writing test sequence for each type of register test-case. With the proposed flow, designers can save considerable amount of time to verify functionality of registers. PMID:27483924

  20. Analysis of Alcove 8/Niche 3 Flow and Transport Tests

    SciTech Connect

    H.H. Liu

    2006-09-01

    The purpose of this report is to document analyses of the Alcove 8/Niche 3 flow and transport tests, with a focus on the large-infiltration-plot tests and compare pre-test model predictions with the actual test observations. The tests involved infiltration that originated from the floor of Alcove 8 (located in the Enhanced Characterization of Repository Block (ECRB) Cross Drift) and observations of seepage and tracer transport at Niche 3 (located in the Main Drift of the Exploratory Studies Facility (ESF)). The test results are relevant to drift seepage and solute transport in the unsaturated zone (UZ) of Yucca Mountain. The main objective of this analysis was to evaluate the modeling approaches used and the importance of the matrix diffusion process by comparing simulation and actual test observations. The pre-test predictions for the large plot test were found to differ from the observations and the reasons for the differences were documented in this report to partly address CR 6783, which concerns unexpected test results. These unexpected results are discussed and assessed with respect to the current baseline unsaturated zone radionuclide transport model in Sections 6.2.4, 6.3.2, and 6.4.

  1. Conceptual framework for the thermal distribution method of test

    SciTech Connect

    Andrews, J.W.

    1994-11-01

    A Standard Method of Test for residential thermal distribution efficiency is being developed under the auspices of the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). Thermal distribution systems are the ductwork, piping, or other means used to transport heat or cooling effect from the equipment that produces this thermal energy to the building spaces that need it. Because thermal distribution systems are embedded in and interact with the larger building system as a whole, a new set of parameters has been developed to describe these systems. This paper was written to fill a perceived need for a concise introduction to this terminology.

  2. Flow through a mechanical distraction enterogenesis device: a pilot test

    PubMed Central

    Miyasaka, Eiichi A.; Okawada, Manabu; Herman, Richard; Utter, Brent; Luntz, Jonathan; Brei, Diann; Teitelbaum, Daniel H.

    2011-01-01

    Background We tested the coupling portion of a prototype intraluminal distraction enterogenesis device to allow flow-through of simulated enteric contents (SEC) in both pig and human jejunum. Materials and methods SEC was made using 80% corn syrup. Ten cm pig and human intestinal segments had a spoke-shaped 2.2cm coupling adaptor sutured in place intraluminally. The adaptor had a flow-through area of 33.6mm2. SEC was pumped into the proximal part of the intestinal segment at 0.083mL/sec. The times to first passage of SEC through the coupler (first drop), 10mL and 20mL of SEC eluted from the distal end were recorded. Results Mean time to first drop elution was 155±38 seconds with pig, and 149±22 seconds with human bowel (p = 0.8). This corresponded to a hydrostatic pressure of 37.5mmHg before the initial drop passed through. Mean flow rates were 0.094mL/sec in pig bowel and 0.084mL/sec in human bowel (p=0.09). To account for occlusion from luminal debris, a 75% occlusion of coupler holes was studied in the smaller pig bowel to investigate if reductions in flow-through area could be tolerated. Mean time to first drop increased slightly to 171±15 seconds, and the elution rate stayed the same (p=0.5). Conclusions After a physiological level of initial pressure buildup allowing the first drop of SEC to pass the coupling adaptor, our prototype intestinal coupling adaptor did not obstruct flow-through of SEC, even after a 75% decrease in flow-through area. This type of attachment represents a viable approach to placing a device in-continuity without obstructing flow of enteric contents. PMID:21571307

  3. Computational analysis of turbine engine test cell flow phenomena

    NASA Astrophysics Data System (ADS)

    Prufert, Matthew Brian

    1998-11-01

    Turbine engine altitude test cells must incorporate an exhaust system collector to remove hot exhaust gases from the vicinity of the jet engine and to provide additional pumping to simulate the reduced pressure which would be encountered in flight. For economic reasons, it is desirable to utilize the same test configuration to simulate as much of the engine operating envelope as possible. To extend the test envelope, a cut-and-try approach is usually taken using available test data, one-dimensional analyses, and past experience. In this study, a computational approach was used to model some of the recognized operational problems which are commonly encountered. Specifically, computational models were used to evaluate the performance of an altitude test cell at low altitude conditions. Particular emphasis was placed on potential test section over-heating and the reduction of diffuser pumping to achieve near sea-level test conditions. A computational model which utilizes the NPARC Navier-Stokes code was applied to several test configurations operating at steady-state and to a single diffuser configuration in the presence of unsteady pressure fluctuations. During 1997/1998, the author developed two-dimensional and three-dimensional NPARC Navier-Stokes flow models and procedures for use in predicting test cell and engine surface cooling effectiveness for a military engine installation in an altitude test chamber. The predicted model flowfields for both steady-state and time variant flows were used to qualitatively verify limited infrared imaging camera data and quantitatively compare numerical results with test cell and diffuser pressure and temperature data. Prediction of surface convention heat transfer rates are currently beyond the capabilities of the NPARC CFD code. To quantify localized wall heat transfer rates, the BLAYER boundary layer code also was utilized. The BLAYER code is capable of quantifying boundary layer convection heat transfer rates based on near

  4. Jet-Surface Interaction Test: Flow Measurements Results

    NASA Technical Reports Server (NTRS)

    Brown, Cliff; Wernet, Mark

    2014-01-01

    Modern aircraft design often puts the engine exhaust in close proximity to the airframe surfaces. Aircraft noise prediction tools must continue to develop in order to meet the challenges these aircraft present. The Jet-Surface Interaction Tests have been conducted to provide a comprehensive quality set of experimental data suitable for development and validation of these exhaust noise prediction methods. Flow measurements have been acquired using streamwise and cross-stream particle image velocimetry (PIV) and fluctuating surface pressure data acquired using flush mounted pressure transducers near the surface trailing edge. These data combined with previously reported far-field and phased array noise measurements represent the first step toward the experimental data base. These flow data are particularly applicable to development of noise prediction methods which rely on computational fluid dynamics to uncover the flow physics. A representative sample of the large flow data set acquired is presented here to show how a surface near a jet affects the turbulent kinetic energy in the plume, the spatial relationship between the jet plume and surface needed to generate surface trailing-edge noise, and differences between heated and unheated jet flows with respect to surfaces.

  5. Performance testing of a Savonius windmill rotor in shear flows

    NASA Astrophysics Data System (ADS)

    Mojola, O. O.; Onasanya, O. E.

    The effects of flow shear and/or unsteadiness on the power producing performance of a Savonius windmill rotor are studied. Measurements are made in two laboratory statistically-steady shear flows, and in the natural wind, which is both viscous and unsteady. The measurements were made of the speed, torque, and power of the rotor at a number of streamwise stations for each of four values of the bucket overlap ratio. Flow velocity profiles and graphs of wind shear variation are given. It is concluded that even in the presence of shear, the power coefficient of a Savonius windmill rotor is most strongly dependent on the tip speed ratio. As in inviscid flow, the power coefficient peaked at a tip speed ratio = 0.8. The major effect of shear was to reduce the power coefficient below the inviscid flow level, the magnitude of reduction depending on the magnitude of shear present. In field testing of the Savonius rotor, the unsteadiness of the wind proved to be a greater source of power loss than the wind shear.

  6. Dynamic change of collateral flow varying with distribution of regional blood flow in acute ischemic rat cortex

    NASA Astrophysics Data System (ADS)

    Wang, Zhen; Luo, Weihua; Zhou, Fangyuan; Li, Pengcheng; Luo, Qingming

    2012-12-01

    Cerebral blood flow (CBF) is critical for the maintenance of cerebral function by guaranteed constant oxygen and glucose supply to brain. Collateral channels (CCs) are recruited to provide alternatives to CBF to ischemic regions once the primary vessel is occluded during ischemic stroke. However, the knowledge of the relationship between dynamic evolution of collateral flow and the distribution of regional blood flow remains limited. In this study, laser speckle imaging was used to assess dynamic changes of CCs and regional blood flow in a rat cortex with permanent middle cerebral artery occlusion (MCAo). We found that CCs immediately provided blood flow to ischemic territories after MCAo. More importantly, there were three kinds of dynamic changes of CCs during acute stroke: persistent CC, impermanent CC, and transient CC, respectively, related to different distributions of regional blood flow. Although there was the possible occurrence of peri-infarct depolarization (PID) during ischemia, there was no obvious significance about the onset time and duration of CCs between rats with and without PID. These results suggest that the initial arising of CCs does not ensure their persistence, and that collateral flow could be varied with distribution of regional blood flow in acute ischemic stroke, which may facilitate the understanding of collateral recruitment and promote the development of collateral therapeutics in the future.

  7. An Efficacious Multi-Objective Fuzzy Linear Programming Approach for Optimal Power Flow Considering Distributed Generation

    PubMed Central

    Warid, Warid; Hizam, Hashim; Mariun, Norman; Abdul-Wahab, Noor Izzri

    2016-01-01

    This paper proposes a new formulation for the multi-objective optimal power flow (MOOPF) problem for meshed power networks considering distributed generation. An efficacious multi-objective fuzzy linear programming optimization (MFLP) algorithm is proposed to solve the aforementioned problem with and without considering the distributed generation (DG) effect. A variant combination of objectives is considered for simultaneous optimization, including power loss, voltage stability, and shunt capacitors MVAR reserve. Fuzzy membership functions for these objectives are designed with extreme targets, whereas the inequality constraints are treated as hard constraints. The multi-objective fuzzy optimal power flow (OPF) formulation was converted into a crisp OPF in a successive linear programming (SLP) framework and solved using an efficient interior point method (IPM). To test the efficacy of the proposed approach, simulations are performed on the IEEE 30-busand IEEE 118-bus test systems. The MFLP optimization is solved for several optimization cases. The obtained results are compared with those presented in the literature. A unique solution with a high satisfaction for the assigned targets is gained. Results demonstrate the effectiveness of the proposed MFLP technique in terms of solution optimality and rapid convergence. Moreover, the results indicate that using the optimal DG location with the MFLP algorithm provides the solution with the highest quality. PMID:26954783

  8. An Efficacious Multi-Objective Fuzzy Linear Programming Approach for Optimal Power Flow Considering Distributed Generation.

    PubMed

    Warid, Warid; Hizam, Hashim; Mariun, Norman; Abdul-Wahab, Noor Izzri

    2016-01-01

    This paper proposes a new formulation for the multi-objective optimal power flow (MOOPF) problem for meshed power networks considering distributed generation. An efficacious multi-objective fuzzy linear programming optimization (MFLP) algorithm is proposed to solve the aforementioned problem with and without considering the distributed generation (DG) effect. A variant combination of objectives is considered for simultaneous optimization, including power loss, voltage stability, and shunt capacitors MVAR reserve. Fuzzy membership functions for these objectives are designed with extreme targets, whereas the inequality constraints are treated as hard constraints. The multi-objective fuzzy optimal power flow (OPF) formulation was converted into a crisp OPF in a successive linear programming (SLP) framework and solved using an efficient interior point method (IPM). To test the efficacy of the proposed approach, simulations are performed on the IEEE 30-busand IEEE 118-bus test systems. The MFLP optimization is solved for several optimization cases. The obtained results are compared with those presented in the literature. A unique solution with a high satisfaction for the assigned targets is gained. Results demonstrate the effectiveness of the proposed MFLP technique in terms of solution optimality and rapid convergence. Moreover, the results indicate that using the optimal DG location with the MFLP algorithm provides the solution with the highest quality. PMID:26954783

  9. A review of flow battery testing at Sandia

    SciTech Connect

    Butler, P.C.; Miller, D.W.; Robinson, C.E.; Rodriguez, G.P.

    1984-08-01

    Sandia National Laboratories is evaluating prototype zinc/bromine, Redox, and zinc/ferricyanide flowing electrolyte batteries and cells. This paper updates previous reports of test results of two Exxon zinc/bromine batteries and one NASA Redox iron/chromium battery. Two 60sq. cm. zinc/ferricyanide cells from Lockheed Missiles and Space Co. are also being evaluated. Performance, life, and operating data are described for these batteries and cells.

  10. Flammable gas interlock spoolpiece flow response test report

    SciTech Connect

    Schneider, T.C., Fluor Daniel Hanford

    1997-03-24

    The purpose of this test report is to document the testing performed under the guidance of HNF-SD-WM-TC-073, {ital Flammable Gas Interlock Spoolpiece Flow Response Test Plan and Procedure}. This testing was performed for Lockheed Martin Hanford Characterization Projects Operations (CPO) in support of Rotary Mode Core Sampling jointly by SGN Eurisys Services Corporation and Numatec Hanford Company. The testing was conducted in the 305 building Engineering Testing Laboratory (ETL). NHC provides the engineering and technical support for the 305 ETL. The key personnel identified for the performance of this task are as follows: Test responsible engineering manager, C. E. Hanson; Flammable Gas Interlock Design Authority, G. P. Janicek; 305 ETL responsible manager, N. J. Schliebe; Cognizant RMCS exhauster engineer, E. J. Waldo/J. D. Robinson; Cognizant 305 ETL engineer, K. S. Witwer; Test director, T. C. Schneider. Other support personnel were supplied, as necessary, from 305/306 ETL. The testing, on the flammable Gas Interlock (FGI) system spoolpiece required to support Rotary Mode Core Sampling (RMCS) of single shell flammable gas watch list tanks, took place between 2-13-97 and 2-25-97.

  11. Radial flow permeability testing of an argillaceous limestone.

    PubMed

    Selvadurai, A P S; Jenner, L

    2013-01-01

    Argillaceous Lindsay limestone is the geologic storage formation that will be encountered at the site for the construction of a deep ground repository in Ontario, Canada, for the storage of low to intermediate level nuclear waste. The permeability of the Lindsay limestone is a key parameter that will influence the long-term movement of radionuclides from the repository to the geosphere. This paper describes the use of both steady-state and transient radial flow laboratory tests to determine the permeability of this argillaceous limestone. The interpretation of the tests is carried out using both analytical results and computational models of flow problems that exhibit radial symmetry. The results obtained from this research investigation are compared with the data available in the literature for similar argillaceous limestones mainly found in the Lindsay (Cobourg) formation. The experiments give permeabilities in the range of 1.0 × 10(-22) to 1.68 × 10(-19) m(2) for radial flows that are oriented along bedding planes under zero axial stress. The factors influencing transient pulse tests in particular and the interpretation of the results are discussed. PMID:22489872

  12. Enthalpy Distributions of Arc Jet Flow Based on Measured Laser Induced Fluorescence, Heat Flux and Stagnation Pressure Distributions

    NASA Technical Reports Server (NTRS)

    Suess, Leonard E.; Milhoan, James D.; Oelke, Lance; Godfrey, Dennis; Larin, Maksim Y.; Scott, Carl D.; Grinstead, Jay H.; DelPapa, Steven

    2011-01-01

    The centerline total enthalpy of arc jet flow is determined using laser induced fluorescence of oxygen and nitrogen atoms. Each component of the energy, kinetic, thermal, and chemical can be determined from LIF measurements. Additionally, enthalpy distributions are inferred from heat flux and pressure probe distribution measurements using an engineering formula. Average enthalpies are determined by integration over the radius of the jet flow, assuming constant mass flux and a mass flux distribution estimated from computational fluid dynamics calculations at similar arc jet conditions. The trends show favorable agreement, but there is an uncertainty that relates to the multiple individual measurements and assumptions inherent in LIF measurements.

  13. Modeling free molecular plume flow and impingement by an ellipsoidal distribution function

    NASA Astrophysics Data System (ADS)

    Legge, Hubert

    Modeling frozen plume flow is outlined using a freezing surface and an ellipsoidal distribution function beyond a freezing surface. Formulas are given for the number flux, pressure, shear stress, and heat-transfer on a surface element in free molecular flow with an ellipsoidal distribution function. To demonstrate the accuracy of the modeling, the method is applied to the totally frozen Knudsen effusion, for which the flow quantities are given. For the given example, the accuracy is better than 2.5 percent.

  14. Facility for cold flow testing of solid rocket motor models

    NASA Astrophysics Data System (ADS)

    Bacchus, D. L.; Hill, O. E.; Whitesides, R. Harold

    1992-02-01

    A new cold flow test facility was designed and constructed at NASA Marshall Space Flight Center for the purpose of characterizing the flow field in the port and nozzle of solid propellant rocket motors (SRM's). A National Advisory Committee was established to include representatives from industry, government agencies, and universities to guide the establishment of design and instrumentation requirements for the new facility. This facility design includes the basic components of air storage tanks, heater, submicron filter, quiet control valve, venturi, model inlet plenum chamber, solid rocket motor (SRM) model, exhaust diffuser, and exhaust silencer. The facility was designed to accommodate a wide range of motor types and sizes from small tactical motors to large space launch boosters. This facility has the unique capability of testing ten percent scale models of large boosters such as the new Advanced Solid Rocket Motor (ASRM), at full scale motor Reynolds numbers. Previous investigators have established the validity of studying basic features of solid rocket motor development programs include the acquisition of data to (1) directly evaluate and optimize the design configuration of the propellant grain, insulation, and nozzle; and (2) provide data for validation of the computational fluid dynamics, (CFD), analysis codes and the performance analysis codes. A facility checkout model was designed, constructed, and utilized to evaluate the performance characteristics of the new facility. This model consists of a cylindrical chamber and converging/diverging nozzle with appropriate manifolding to connect it to the facility air supply. It was designed using chamber and nozzle dimensions to simulate the flow in a 10 percent scale model of the ASRM. The checkout model was recently tested over the entire range of facility flow conditions which include flow rates from 9.07 to 145 kg/sec (20 to 320 Ibm/sec) and supply pressure from 5.17 x 10 exp 5 to 8.27 x 10 exp 6 Pa. The

  15. 242A Distributed Control System Year 2000 Acceptance Test Report

    SciTech Connect

    TEATS, M.C.

    1999-08-31

    This report documents acceptance test results for the 242-A Evaporator distributive control system upgrade to D/3 version 9.0-2 for year 2000 compliance. This report documents the test results obtained by acceptance testing as directed by procedure HNF-2695. This verification procedure will document the initial testing and evaluation of the potential 242-A Distributed Control System (DCS) operating difficulties across the year 2000 boundary and the calendar adjustments needed for the leap year. Baseline system performance data will be recorded using current, as-is operating system software. Data will also be collected for operating system software that has been modified to correct year 2000 problems. This verification procedure is intended to be generic such that it may be performed on any D/3{trademark} (GSE Process Solutions, Inc.) distributed control system that runs with the VMSTM (Digital Equipment Corporation) operating system. This test may be run on simulation or production systems depending upon facility status. On production systems, DCS outages will occur nine times throughout performance of the test. These outages are expected to last about 10 minutes each.

  16. HammerCloud: A Stress Testing System for Distributed Analysis

    NASA Astrophysics Data System (ADS)

    van der Ster, Daniel C.; Elmsheuser, Johannes; Úbeda García, Mario; Paladin, Massimo

    2011-12-01

    Distributed analysis of LHC data is an I/O-intensive activity which places large demands on the internal network, storage, and local disks at remote computing facilities. Commissioning and maintaining a site to provide an efficient distributed analysis service is therefore a challenge which can be aided by tools to help evaluate a variety of infrastructure designs and configurations. HammerCloud is one such tool; it is a stress testing service which is used by central operations teams, regional coordinators, and local site admins to (a) submit arbitrary number of analysis jobs to a number of sites, (b) maintain at a steady-state a predefined number of jobs running at the sites under test, (c) produce web-based reports summarizing the efficiency and performance of the sites under test, and (d) present a web-interface for historical test results to both evaluate progress and compare sites. HammerCloud was built around the distributed analysis framework Ganga, exploiting its API for grid job management. HammerCloud has been employed by the ATLAS experiment for continuous testing of many sites worldwide, and also during large scale computing challenges such as STEP'09 and UAT'09, where the scale of the tests exceeded 10,000 concurrently running and 1,000,000 total jobs over multi-day periods. In addition, HammerCloud is being adopted by the CMS experiment; the plugin structure of HammerCloud allows the execution of CMS jobs using their official tool (CRAB).

  17. On-line updating of a distributed flow routing model - River Vistula case study

    NASA Astrophysics Data System (ADS)

    Karamuz, Emilia; Romanowicz, Renata; Napiorkowski, Jaroslaw

    2015-04-01

    This paper presents an application of methods of on-line updating in the River Vistula flow forecasting system. All flow-routing codes make simplifying assumptions and consider only a reduced set of the processes known to occur during a flood. Hence, all models are subject to a degree of structural error that is typically compensated for by calibration of the friction parameters. Calibrated parameter values are not, therefore, physically realistic, as in estimating them we also make allowance for a number of distinctly non-physical effects, such as model structural error and any energy losses or flow processes which occur at sub-grid scales. Calibrated model parameters are therefore area-effective, scale-dependent values which are not drawn from the same underlying statistical distribution as the equivalent at-a-point parameter of the same name. The aim of this paper is the derivation of real-time updated, on-line flow forecasts at certain strategic locations along the river, over a specified time horizon into the future, based on information on the behaviour of the flood wave upstream and available on-line measurements at a site. Depending on the length of the river reach and the slope of the river bed, a realistic forecast lead time, obtained in this manner, may range from hours to days. The information upstream can include observations of river levels and/or rainfall measurements. The proposed forecasting system will integrate distributed modelling, acting as a spatial interpolator with lumped parameter Stochastic Transfer Function models. Daily stage data from gauging stations are typically available at sites 10-60 km apart and test only the average routing performance of hydraulic models and not their ability to produce spatial predictions. Application of a distributed flow routing model makes it possible to interpolate forecasts both in time and space. This work was partly supported by the project "Stochastic flood forecasting system (The River Vistula reach

  18. Nevada test site radionuclide inventory and distribution: project operations plan

    SciTech Connect

    Kordas, J.F.; Anspaugh, L.R.

    1982-06-01

    This document is the operational plan for conducting the Radionuclide Inventory and Distribution Program (RIDP) at the Nevada Test Site (NTS). The basic objective of this program is to inventory the significant radionuclides of NTS origin in NTS surface soil. The expected duration of the program is five years. This plan includes the program objectives, methods, organization, and schedules.

  19. 21 CFR 211.165 - Testing and release for distribution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Testing and release for distribution. 211.165 Section 211.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS...

  20. 21 CFR 211.165 - Testing and release for distribution.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 4 2012-04-01 2012-04-01 false Testing and release for distribution. 211.165 Section 211.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS...

  1. 21 CFR 211.165 - Testing and release for distribution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 4 2011-04-01 2011-04-01 false Testing and release for distribution. 211.165 Section 211.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS...

  2. 21 CFR 211.165 - Testing and release for distribution.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 4 2013-04-01 2013-04-01 false Testing and release for distribution. 211.165 Section 211.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS...

  3. 21 CFR 211.165 - Testing and release for distribution.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 4 2014-04-01 2014-04-01 false Testing and release for distribution. 211.165 Section 211.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR FINISHED PHARMACEUTICALS...

  4. Pressure and flow distribution in internal gas manifolds of a fuel-cell stack

    NASA Astrophysics Data System (ADS)

    Koh, Joon-Ho; Seo, Hai-Kyung; Lee, Choong Gon; Yoo, Young-Sung; Lim, Hee Chun

    Gas-flow dynamics in internal gas manifolds of a fuel-cell stack are analyzed to investigate overall pressure variation and flow distribution. Different gas-flow patterns are considered in this analysis. Gas-flow through gas channels of each cell is modeled by means of Darcy's law where permeability should be determined on an experimental basis. Gas-flow in manifolds is modeled from the macroscopic mechanical energy balance with pressure-loss by wall friction and geometrical effects. A systematic algorithm to solve the proposed flow model is suggested to calculate pressure and flow distribution in fuel-cell stacks. Calculation is done for a 100-cell molten carbonate fuel-cell stack with internal manifolds. The results show that the pressure-loss by wall friction is negligible compared with the pressure recovery in inlet manifolds or loss in outlet manifolds due to mass dividing or combining flow at manifold-cell junctions. A more significant effect on manifold pressure possibly arises from the geometrical manifold structure which depends on the manifold size and shape. The geometrical effect is approximated from pressure-loss coefficients of several types of fittings and valves. The overall pressure and flow distribution is significantly affected by the value of the geometrical pressure-loss coefficient. It is also found that the flow in manifolds is mostly turbulent in the 100-cell stack and this way result in an uneven flow distribution when the stack manifold is incorrectly, designed.

  5. Spectral distributed Lagrange multiplier method: algorithm and benchmark tests

    NASA Astrophysics Data System (ADS)

    Dong, Suchuan; Liu, Dong; Maxey, Martin R.; Karniadakis, George Em

    2004-04-01

    We extend the formulation of the distributed Lagrange multiplier (DLM) approach for particulate flows to high-order methods within the spectral/ hp element framework. We implement the rigid-body motion constraint inside the particle via a penalty method. The high-order DLM method demonstrates spectral convergence rate, i.e. discretization errors decrease exponentially as the order of spectral polynomials increases. We provide detailed comparisons between the spectral DLM method, direct numerical simulations, and the force coupling method for a number of 2D and 3D benchmark flow problems. We also validate the spectral DLM method with available experimental data for a transient problem. The new DLM method can potentially be very effective in many-moving body problems, where a smaller number of grid points is required in comparison with low-order methods.

  6. Nature and extent of lava-flow aquifers beneath Pahute Mesa, Nevada Test Site

    SciTech Connect

    Prothro, L.B.; Drellack, S.L. Jr.

    1997-09-01

    Work is currently underway within the Underground Test Area subproject of the US Department of Energy/Nevada Operations Office Environmental Restoration Program to develop corrective action plans in support of the overall corrective action strategy for the Nevada Test Site as established in the Federal Facility Agreement and Consent Order (FFACO, 1996). A closure plan is currently being developed for Pahute Mesa, which has been identified in the FFACO as consisting of the Western and Central Pahute Mesa Corrective Action Units. Part of this effort requires that hydrogeologic data be compiled for inclusion in a regional model that will be used to predict a contaminant boundary for these Corrective Action Units. Hydrogeologic maps have been prepared for use in the model to define the nature and extent of aquifers and confining units that might influence the flow of contaminated groundwater from underground nuclear tests conducted at Pahute Mesa. Much of the groundwater flow beneath Pahute Mesa occurs within lava-flow aquifers. An understanding of the distribution and hydraulic character of these important hydrogeologic units is necessary to accurately model groundwater flow beneath Pahute Mesa. This report summarizes the results of a study by Bechtel Nevada geologists to better define the hydrogeology of lava-flow aquifers at Pahute Mesa. The purpose of this study was twofold: (1) aid in the development of the hydrostratigraphic framework for Pahute Mesa, and (2) provide information on the distribution and hydraulic character of lava-flow aquifers beneath Pahute Mesa for more accurate computer modeling of the Western and Central Pahute Mesa Corrective Action Units.

  7. 42 CFR 84.93 - Gas flow test; open-circuit apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Gas flow test; open-circuit apparatus. 84.93...-Contained Breathing Apparatus § 84.93 Gas flow test; open-circuit apparatus. (a) A static-flow test will be performed on all open-circuit apparatus. (b) The flow from the apparatus shall be greater than 200...

  8. 42 CFR 84.93 - Gas flow test; open-circuit apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Gas flow test; open-circuit apparatus. 84.93...-Contained Breathing Apparatus § 84.93 Gas flow test; open-circuit apparatus. (a) A static-flow test will be performed on all open-circuit apparatus. (b) The flow from the apparatus shall be greater than 200...

  9. Utilization of temperature distribution in expiratory speaking flow as a new parameter for speech production analysis.

    PubMed

    Gomes, G F; Vargas, J V C; Filho, E D M

    2004-01-01

    A new instrument with potential use for speech production analysis is utilized in this study to measure the temperature and velocity of the expiratory speaking flow outside the oral cavity. From a physical point of view, the temperature patterns of individuals with healthy voices are expected to be different from individuals with breathy voices, since their air flow patterns are different: during breathy speech production, the glottis does not close completely, and the leakage of warm air through the glottis increases the extent of the hotter-than-ambient temperature field outside the oral cavity. The instrument is a pipe through which the tested individual breathes out while producing a sustained vowel. A tap water heat exchanger keeps the pipe wall at a temperature level considerably lower than the body temperature. The temperature gradient along the pipe centreline is measured and related to the average air velocity at the oral cavity. The measurements were performed in 30 male and 30 female subjects without vocal complaints. The objective of this initial investigation was to evaluate the possibility of establishing patterns of normality for the temperature distribution outside the oral cavity in expiratory speaking flow. In the experiments, all the temperature measurements increased as the expiratory air flow of the individual increased during speech production, therefore the instrument results agree with the physical behavior predicted by fluid mechanics and heat transfer principles. The collected data allowed for the construction of charts with two distinct normalized temperature distributions outside the oral cavity, for male and female individuals, respectively. These charts have the potential for future utilization in a follow-up study for comparison with similar measurements obtained with individuals with vocal fold pathologies, aiming to eventually produce a reliable new instrument for early detection of vocal problems through a non-invasive procedure

  10. Lateral flow-based antibody testing for Chlamydia trachomatis.

    PubMed

    Gwyn, Sarah; Mitchell, Alexandria; Dean, Deborah; Mkocha, Harran; Handali, Sukwan; Martin, Diana L

    2016-08-01

    We describe here a lateral flow-based assay (LFA) for the detection of antibodies against immunodominant antigen Pgp3 from Chlamydia trachomatis, the causative agent of urogenital chlamydia infection and ocular trachoma. Optimal signal detection was achieved when the gold-conjugate and test line contained Pgp3, creating a dual sandwich capture assay. The LFA yielded positive signals with serum and whole blood but not with eluted dried blood spots. For serum, the agreement of the LFA with the non-reference multiplex assay was 96%, the specificity using nonendemic pediatric sera was 100%, and the inter-rater agreement was κ=0.961. For whole blood, the agreement of LFA with multiplex was 81.5%, the specificity was 100%, and the inter-rater agreement was κ=0.940. The LFA was tested in a field environment and yielded similar results to those from laboratory-based testing. These data show the successful development of a lateral flow assay for detection of antibodies against Pgp3 with reliable use in field settings, which would make antibody-based testing for trachoma surveillance highly practical, especially after cessation of trachoma elimination programs. PMID:27208400

  11. A new Goodness-of-fit test for Frequency Analysis of Peak Flows in L-moment Framework

    NASA Astrophysics Data System (ADS)

    Basu, Bidroha; Srinivas Vemavarapu, Venkata

    2015-04-01

    Over the past two decades, L-moment based flood frequency analysis (FFA) procedure is being extensively used in hydrology for estimation of flood quantiles at target locations in river basins. The procedure is based on the assumption that (i) peak flows at a location constitute a sample drawn from one of the known frequency distributions such as Generalized extreme value (GEV), Generalized Pareto (GPA), and Pearson Type III (PE3), and (ii) the distribution can be identified using L-moment ratio diagram. Through Monte-Carlo simulation experiments it would be demonstrated that conventional L-moment goodness-of-fit (GOF) test, which is widely used for identifying the best-fit frequency distribution, may not be effective in identifying true distribution (population) corresponding to samples, when L-moments specified for sample generation belong to certain ranges. The ranges identified corresponding to various forms of frequency distributions would be presented and discussed. To overcome the limitation of L-moment GOF test, an alternate test would be presented, which examines the hypothesis that peak flow data follows GEV, GPA, PE3, Generalized Logistic or Generalized Normal distributions. The proposed test involves: (i) use of a transformation mechanism to map peak flows from the original space to a dimensionless space where the form of their frequency distribution does not change, (ii) estimation of location, scale and shape parameters of the hypothesized distribution using the transformed data, (iii) computation of deviation of the estimated parameters with respect to their population values that are determined based on analytic formulations proposed by the authors in a previous work, and (iv) considering the deviation as the basis to accept/reject the hypothesis that the chosen distribution is appropriate to fit the peak flow data. The proposed GOF test would be demonstrated to be effective compared to conventional L-moment GOF test through Monte-Carlo simulation

  12. Measurement of energy distribution in flowing hydrogen microwave plasmas

    NASA Technical Reports Server (NTRS)

    Chapman, R.; Morin, T.; Finzel, M.; Hawley, M. C.

    1985-01-01

    An electrothermal propulsion concept utilizing a microwave plasma system as the mechanism to convert electromagnetic energy into kinetic energy of a flowing gas is investigated. A calorimetry system enclosing a microwave plasma system has been developed to accurately measure the energy inputs and outputs of the microwave plasma system. The rate of energy transferred to the gas can be determined to within + or - 1.8 W from an energy balance around the microwave plasma system. The percentage of the power absorbed by the microwave plasma system transferred to the hydrogen gas as it flows through the system is found to increase with the increasing flow rate, to decrease with the increasing pressure, and to be independent of the absorbed power. An upper bound for the hydrogen gas temperature is estimated from the energy content, heat capacity, and flow rate of the gas stream. A lower bound for an overall heat-transfer coefficient is then calculated, characterizing the energy loss from the hydrogen gas stream to the air cooling of the plasma discharge tube wall. The heat-transfer coefficient is found to increase with the increasing flow rate and pressure and to be independent of the absorbed power. This result indicates that a convective-type mechanism is responsible for the energy transfer.

  13. FishMORPH - An agent-based model to predict salmonid growth and distribution responses under natural and low flows

    PubMed Central

    Phang, S. C.; Stillman, R. A.; Cucherousset, J.; Britton, J. R.; Roberts, D.; Beaumont, W. R. C.; Gozlan, R. E.

    2016-01-01

    Predicting fish responses to modified flow regimes is becoming central to fisheries management. In this study we present an agent-based model (ABM) to predict the growth and distribution of young-of-the-year (YOY) and one-year-old (1+) Atlantic salmon and brown trout in response to flow change during summer. A field study of a real population during both natural and low flow conditions provided the simulation environment and validation patterns. Virtual fish were realistic both in terms of bioenergetics and feeding. We tested alternative movement rules to replicate observed patterns of body mass, growth rates, stretch distribution and patch occupancy patterns. Notably, there was no calibration of the model. Virtual fish prioritising consumption rates before predator avoidance replicated observed growth and distribution patterns better than a purely maximising consumption rule. Stream conditions of low predation and harsh winters provide ecological justification for the selection of this behaviour during summer months. Overall, the model was able to predict distribution and growth patterns well across both natural and low flow regimes. The model can be used to support management of salmonids by predicting population responses to predicted flow impacts and associated habitat change. PMID:27431787

  14. FishMORPH - An agent-based model to predict salmonid growth and distribution responses under natural and low flows.

    PubMed

    Phang, S C; Stillman, R A; Cucherousset, J; Britton, J R; Roberts, D; Beaumont, W R C; Gozlan, R E

    2016-01-01

    Predicting fish responses to modified flow regimes is becoming central to fisheries management. In this study we present an agent-based model (ABM) to predict the growth and distribution of young-of-the-year (YOY) and one-year-old (1+) Atlantic salmon and brown trout in response to flow change during summer. A field study of a real population during both natural and low flow conditions provided the simulation environment and validation patterns. Virtual fish were realistic both in terms of bioenergetics and feeding. We tested alternative movement rules to replicate observed patterns of body mass, growth rates, stretch distribution and patch occupancy patterns. Notably, there was no calibration of the model. Virtual fish prioritising consumption rates before predator avoidance replicated observed growth and distribution patterns better than a purely maximising consumption rule. Stream conditions of low predation and harsh winters provide ecological justification for the selection of this behaviour during summer months. Overall, the model was able to predict distribution and growth patterns well across both natural and low flow regimes. The model can be used to support management of salmonids by predicting population responses to predicted flow impacts and associated habitat change. PMID:27431787

  15. Motif distributions in phase-space networks for characterizing experimental two-phase flow patterns with chaotic features.

    PubMed

    Gao, Zhong-Ke; Jin, Ning-De; Wang, Wen-Xu; Lai, Ying-Cheng

    2010-07-01

    The dynamics of two-phase flows have been a challenging problem in nonlinear dynamics and fluid mechanics. We propose a method to characterize and distinguish patterns from inclined water-oil flow experiments based on the concept of network motifs that have found great usage in network science and systems biology. In particular, we construct from measured time series phase-space complex networks and then calculate the distribution of a set of distinct network motifs. To gain insight, we first test the approach using time series from classical chaotic systems and find a universal feature: motif distributions from different chaotic systems are generally highly heterogeneous. Our main finding is that the distributions from experimental two-phase flows tend to be heterogeneous as well, suggesting the underlying chaotic nature of the flow patterns. Calculation of the maximal Lyapunov exponent provides further support for this. Motif distributions can thus be a feasible tool to understand the dynamics of realistic two-phase flow patterns. PMID:20866710

  16. Higher-order axial singularity distributions for potential flow about bodies of revolution

    NASA Astrophysics Data System (ADS)

    Zedan, M. F.; Dalton, C.

    1980-03-01

    The approach of using axial singularity distributions of different orders for representing bodies of revolution in axial flow to solve both the direct and inverse problems has been developed and critically evaluated. A polynomial of arbitrary degree is used to represent the variation of the intensity of the source distribution over each element. The effects of the order of the distribution, the number of elements, the normalization of the body coordinates, the fineness ratio and the geometry of the profile on the performance of the method have been studied in detail by using a number of test cases of known solutions. With appropriate choice of these parameters, this approach for both the direct and inverse axisymmetric problems can be as accurate as the surface singularity approach even for simple bodies with inflection points. However, the present scheme has the advantage of being much simpler and faster. A new technique has been developed for the calculation of the body radius in the iterative inverse problem scheme. This technique proved to be essential for velocity distributions representing bodies with inflection points. Such bodies are of great interest in the design of low-drag shapes.

  17. Parametric Testing of Chevrons on Single Flow Hot Jets

    NASA Technical Reports Server (NTRS)

    Bridges, James; Brown, Clifford A.

    2004-01-01

    A parametric family of chevron nozzles have been studied, looking for relationships between chevron geometric parameters, flow characteristics, and far-field noise. Both cold and hot conditions have been run at acoustic Mach number 0.9. Ten models have been tested, varying chevron count, penetration, length, and chevron symmetry. Four comparative studies were defined from these datasets which show: that chevron length is not a major impact on either flow or sound; that chevron penetration increases noise at high frequency and lowers it at low frequency, especially for low chevron counts; that chevron count is a strong player with good low frequency reductions being achieved with high chevron count without strong high frequency penalty; and that chevron asymmetry slightly reduces the impact of the chevron. Finally, it is shown that although the hot jets differ systematically from the cold one, the overall trends with chevron parameters is the same.

  18. Testing of models of flow-induced hemolysis in blood flow through hypodermic needles.

    PubMed

    Chen, Yangsheng; Kent, Timothy L; Sharp, M Keith

    2013-03-01

    Hemolysis caused by flow in hypodermic needles interferes with a number of tests on blood samples drawn by venipuncture, including assays for metabolites, electrolytes, and enzymes, causes discomfort during dialysis sessions, and limits transfusion flow rates. To evaluate design modifications to address this problem, as well as hemolysis issues in other cardiovascular devices, computational fluid dynamics (CFD)-based prediction of hemolysis has potential for reducing the time and expense for testing of prototypes. In this project, three CFD-integrated blood damage models were applied to flow-induced hemolysis in 16-G needles and compared with experimental results, which demonstrated that a modified needle with chamfered entrance increased hemolysis, while a rounded entrance decreased hemolysis, compared with a standard needle with sharp entrance. After CFD simulation of the steady-state velocity field, the time histories of scalar stress along a grid of streamlines were calculated. A strain-based cell membrane failure model and two empirical power-law blood damage models were used to predict hemolysis on each streamline. Total hemolysis was calculated by weighting the predicted hemolysis along each streamline by the flow rate along each streamline. The results showed that only the strain-based blood damage model correctly predicted increased hemolysis in the beveled needle and decreased hemolysis in the rounded needle, while the power-law models predicted the opposite trends. PMID:23419169

  19. Flight Tests of a Supersonic Natural Laminar Flow Airfoil

    NASA Technical Reports Server (NTRS)

    Frederick, Mike; Banks, Dan; Garzon, Andres; Matisheck, Jason

    2014-01-01

    IR thermography was used to characterize the transition front on a S-NLF test article at chord Reynolds numbers in excess of 30 million Changes in transition due to Mach number, Reynolds number, and surface roughness were investigated - Regions of laminar flow in excess of 80% chord at chord Reynolds numbers greater than 14 million IR thermography clearly showed the transition front and other flow features such as shock waves impinging upon the surface A series of parallel oblique shocks, of yet unknown origin, were found to cause premature transition at higher Reynolds numbers. NASA has a current goal to eliminate barriers to the development of practical supersonic transport aircraft Drag reduction through the use of supersonic natural laminar flow (S-NLF) is currently being explored as a means of increasing aerodynamic efficiency - Tradeoffs work best for business jet class at M<2 Conventional high-speed designs minimize inviscid drag at the expense of viscous drag - Existence of strong spanwise pressure gradient leads to crossflow (CF) while adverse chordwise pressure gradients amplifies and Tollmien-Schlichting (TS) instabilities Aerion Corporation has patented a S-NLF wing design (US Patent No. 5322242) - Low sweep to control CF - dp/dx < 0 on both wing surfaces to stabilize TS - Thin wing with sharp leading edge to minimize wave drag increase due to reduction in sweep NASA and Aerion have partnered to study S-NLF since 1999 Series of S-NLF experiments flown on the NASA F-15B research test bed airplane Infrared (IR) thermography used to characterize transition - Non-intrusive, global, good spatial resolution - Captures significant flow features well

  20. Effects of perfluorohexane vapor on relative blood flow distribution in an animal model of surfactant-depleted lung injury

    NASA Technical Reports Server (NTRS)

    Hubler, Matthias; Souders, Jennifer E.; Shade, Erin D.; Polissar, Nayak L.; Bleyl, Jorg U.; Hlastala, Michael P.

    2002-01-01

    OBJECTIVE: To test the hypothesis that treatment with vaporized perfluorocarbon affects the relative pulmonary blood flow distribution in an animal model of surfactant-depleted acute lung injury. DESIGN: Prospective, randomized, controlled trial. SETTING: A university research laboratory. SUBJECTS: Fourteen New Zealand White rabbits (weighing 3.0-4.5 kg). INTERVENTIONS: The animals were ventilated with an FIO(2) of 1.0 before induction of acute lung injury. Acute lung injury was induced by repeated saline lung lavages. Eight rabbits were randomized to 60 mins of treatment with an inspiratory perfluorohexane vapor concentration of 0.2 in oxygen. To compensate for the reduced FIO(2) during perfluorohexane treatment, FIO(2) was reduced to 0.8 in control animals. Change in relative pulmonary blood flow distribution was assessed by using fluorescent-labeled microspheres. MEASUREMENTS AND MAIN RESULTS: Microsphere data showed a redistribution of relative pulmonary blood flow attributable to depletion of surfactant. Relative pulmonary blood flow shifted from areas that were initially high-flow to areas that were initially low-flow. During the study period, relative pulmonary blood flow of high-flow areas decreased further in the control group, whereas it increased in the treatment group. This difference was statistically significant between the groups (p =.02) as well as in the treatment group compared with the initial injury (p =.03). Shunt increased in both groups over time (control group, 30% +/- 10% to 63% +/- 20%; treatment group, 37% +/- 20% to 49% +/- 23%), but the changes compared with injury were significantly less in the treatment group (p =.03). CONCLUSION: Short treatment with perfluorohexane vapor partially reversed the shift of relative pulmonary blood flow from high-flow to low-flow areas attributable to surfactant depletion.

  1. Distribution of incompressible flow within interdigitated channels and porous electrodes

    NASA Astrophysics Data System (ADS)

    Kee, Robert J.; Zhu, Huayang

    2015-12-01

    This paper develops a general model with which to evaluate flow uniformity and pressure drop within interdigitated-channel structures, especially in the context of redox flow batteries. The governing equations are cast in dimensionless variables, leading to a set of characteristic dimensionless parameter groups. The systems of governing equations are solved computationally, with the results presented graphically. Because the results are general, the underlying model itself is not needed to apply the quantitative design guidelines. However, the paper presents and discusses all the information required to recreate the model as needed.

  2. Evaluation of pumping induced flow in observation wells during aquifer testing.

    PubMed

    Székely, Ferenc

    2013-01-01

    The vertical variation of drawdown around pumping wells generates an induced flow in the observation wells. A set of governing equations is presented to couple the drawdown variation and the vertical flux distribution in observation wells. A numerical example is performed to justify the governing equations and to verify the solution methods used by the simulation software WT. The example analyzes the effect of skin loss, wellbore storage, and vertical segmentation on the drawdown and induced flow in observation well during pumping. The evaluation of the Fairborn pumping test involves a vertically homogeneous and anisotropic water table aquifer, uniform well-face drawdown conditions in the pumping well and simulation of the drawdown evolution in the observation well with and without the effect of induced flow. The computer calibrations resulted in small differences between the measured and simulated drawdown curves. PMID:23198759

  3. UNSATURATED FLOW IN A CENTRIFUGAL FIELD: MEASUREMENT OF HYDRAULIC CONDUCTIVITY AND TESTING OF DARCY'S LAW.

    USGS Publications Warehouse

    Nimmo, J.R.; Rubin, J.; Hammermeister, D.P.

    1987-01-01

    A method has been developed to establish steady flow of water in unsaturated soil sample spinning in a centrifuge. Theoretical analysis predicts moisture conditions in the sample that depend strongly on soil type and certain operating parameter. For Oakley sand, measurements of flux, water content, and matric potential during and after centrifugation verify that steady state flow can be achieved. Experiments have confirmed the theoretical prediction of a nearly uniform moisture distribution for this medium and have demonstrated that the flow can be effectively one-dimensional. The method was used for steady state measurements of hydraulic conductivity K for relatively dry soil, giving values at low as 7. 6 multiplied by 10** minus **1**1 m/s with data obtained in a few hours. Darcy's law was tested by measuring K for different centrifugal driving forces but with the same water content.

  4. Preliminary Results of Testing of Flow Effects on Evaporator Scaling

    SciTech Connect

    Hu, M.Z.

    2002-02-15

    This investigation has focused on the effects of fluid flow on solids deposition from solutions that simulate the feed to the 2H evaporator at the Savannah River Site. Literature studies indicate that the fluid flow (or shear) affects particle-particle and particle-surface interactions and thus the phenomena of particle aggregation in solution and particle deposition (i.e., scale formation) onto solid surfaces. Experimental tests were conducted with two configurations: (1) using a rheometer to provide controlled shear conditions and (2) using controlled flow of reactive solution through samples of stainless steel tubing. All tests were conducted at 80 C and at high silicon and aluminum concentrations, 0.133 M each, in solutions containing 4 M sodium hydroxide and 1 A4 each of sodium nitrate and sodium nitrite. Two findings from these experiments are important for consideration in developing approaches for reducing or eliminating evaporator scaling problems: (1) The rheometer tests suggested that for the conditions studied, maximum solids deposition occurs at a moderate shear rate, approximately 12 s{sup -1}. That value is expected to be on the order of shear rates that will occur in various parts of the evaporator system; for instance, a 6 gal/min single-phase liquid flow through the 2-in. lift or gravity drain lines would result in a shear rate of approximately 16 s{sup -1}. These results imply that engineering approaches aimed at reducing deposits through increased mixing would need to generate shear near all surfaces significantly greater than 12 s{sup -1}. However, further testing is needed to set a target value for shear that is applicable to evaporator operation. This is because the measured trend is not statistically significant at the 95% confidence interval due to variability in the results. In addition, testing at higher temperatures and lower concentrations of aluminum and silicon would more accurately represent conditions in the evaporator. Without

  5. Corrosion erosion test of SS316 in flowing Pb Bi

    NASA Astrophysics Data System (ADS)

    Kikuchi, K.; Kurata, Y.; Saito, S.; Futakawa, M.; Sasa, T.; Oigawa, H.; Wakai, E.; Miura, K.

    2003-05-01

    Corrosion tests of austenitic stainless tube were done under flowing Pb-Bi conditions for 3000 h at 450 °C. Specimens were 316SS produced as a tubing form with 13.8 mm outer diameter, 2 mm thickness and 40 cm length. During operation, maximum temperature, temperature difference and flow velocity of Pb-Bi at the specimen were kept at 450, 50 °C, and 1 m/s, respectively. After the test, specimen and components of the loop were cut and examined by optical microscope, SEM, EDX, WDX and X-ray diffraction. Pb-Bi adhered on the surface of the specimen even after Pb-Bi was drained out to the storage tank from the circulating loop. Results differed from a stagnant corrosion test in that the specimen surface became rough and the corrosion rate was maximally 0.1 mm/3000 h. Mass transfer from the high temperature to the lower temperature area was observed: crystals of Fe-Cr were found on the tube surface in the low-temperature region. The sizes of crystals varied from 0.1 to 0.2 mm. The depositing crystals were ferrite grains and the chemical composition ratio (mass%) of Fe to Cr was 9:1.

  6. Modeling and testing of two-phase flow in manifolds under microgravity conditions

    NASA Astrophysics Data System (ADS)

    Best, Frederick; Kurwitz, Cable

    2001-02-01

    Previous work relating to two-phase flow in manifolds has dealt primarily with 1-g phase distribution at each junction. Understanding the redistribution of gas and liquid at each junction in microgravity allows the investigator to calculate specific thermal-hydraulic phenomena in each branch or run. A model was developed at Texas A&M to determine the phasic distribution in an arbitrary manifold. Previously developed phase distribution equations are used to describe the redistribution at a dividing T-junction (Young et al., 1999). Mass flow rate, void fraction, and pressure drop are calculated iteratively for the entire manifold. Output from the model was compared to data taken from tests aboard NASA's KC-135. The test manifold consisted of a run with three branches. The system allowed the output to be directed to a phase separator or to collection bags. The distribution of liquid and gas in each collection bag could be used to determine the mass fraction in each branch and run. Results show good agreement between predicted mass fraction and flight data. .

  7. Bulk stress distributions in the pore space of sphere-packed beds under Darcy flow conditions.

    PubMed

    Pham, Ngoc H; Voronov, Roman S; Tummala, Naga Rajesh; Papavassiliou, Dimitrios V

    2014-03-01

    In this paper, bulk stress distributions in the pore space of columns packed with spheres are numerically computed with lattice Boltzmann simulations. Three different ideally packed and one randomly packed configuration of the columns are considered under Darcy flow conditions. The stress distributions change when the packing type changes. In the Darcy regime, the normalized stress distribution for a particular packing type is independent of the pressure difference that drives the flow and presents a common pattern. The three parameter (3P) log-normal distribution is found to describe the stress distributions in the randomly packed beds within statistical accuracy. In addition, the 3P log-normal distribution is still valid when highly porous scaffold geometries rather than sphere beds are examined. It is also shown that the 3P log-normal distribution can describe the bulk stress distribution in consolidated reservoir rocks like Berea sandstone. PMID:24730946

  8. Bulk stress distributions in the pore space of sphere-packed beds under Darcy flow conditions

    NASA Astrophysics Data System (ADS)

    Pham, Ngoc H.; Voronov, Roman S.; Tummala, Naga Rajesh; Papavassiliou, Dimitrios V.

    2014-03-01

    In this paper, bulk stress distributions in the pore space of columns packed with spheres are numerically computed with lattice Boltzmann simulations. Three different ideally packed and one randomly packed configuration of the columns are considered under Darcy flow conditions. The stress distributions change when the packing type changes. In the Darcy regime, the normalized stress distribution for a particular packing type is independent of the pressure difference that drives the flow and presents a common pattern. The three parameter (3P) log-normal distribution is found to describe the stress distributions in the randomly packed beds within statistical accuracy. In addition, the 3P log-normal distribution is still valid when highly porous scaffold geometries rather than sphere beds are examined. It is also shown that the 3P log-normal distribution can describe the bulk stress distribution in consolidated reservoir rocks like Berea sandstone.

  9. Impact of heterogeneous permeability distribution on the groundwater flow systems of a small sedimentary basin

    NASA Astrophysics Data System (ADS)

    Zech, Alraune; Zehner, Björn; Kolditz, Olaf; Attinger, Sabine

    2016-01-01

    Ground water flow systems of shallow sedimentary basins are studied in general by analyzing the fluid dynamics at the real world example of the Thuringian Basin. The impact of the permeability distribution and density differences on the flow velocity pattern, the salt concentration, and the temperature distribution is quantified by means of transient coupled simulations of fluid flow, heat, and mass transport processes. Simulations are performed with different permeabilities in the sedimentary layering and heterogeneous permeability distributions as well as with a non-constant fluid density. Three characteristic numbers are useful to describe the effects of permeability on the development of flow systems and subsurface transport: the relation of permeability between aquiclude and aquifer, the variance, and the correlation length of the log-normal permeability distribution. Density dependent flow due to temperature or concentration gradients is of minor importance for the distribution of the flow systems, but can lead to increased mixing dissolution of salt. Thermal convection is in general not present. The dominant driver of groundwater flow is the topography in combination with the permeability distribution. The results obtained for the Thuringian Basin give general insights into the dynamics of a small sedimentary basin due to the representative character of the basin structure as well as the transferability of the settings to other small sedimentary basins.

  10. LEDA RF distribution system design and component test results

    SciTech Connect

    Roybal, W.T.; Rees, D.E.; Borchert, H.L.; McCarthy, M.; Toole, L.

    1998-12-31

    The 350 MHz and 700 MHz RF distribution systems for the Low Energy Demonstration Accelerator (LEDA) have been designed and are currently being installed at Los Alamos National Laboratory. Since 350 MHz is a familiar frequency used at other accelerator facilities, most of the major high-power components were available. The 700 MHz, 1.0 MW, CW RF delivery system designed for LEDA is a new development. Therefore, high-power circulators, waterloads, phase shifters, switches, and harmonic filters had to be designed and built for this applications. The final Accelerator Production of Tritium (APT) RF distribution systems design will be based on much of the same technology as the LEDA systems and will have many of the RF components tested for LEDA incorporated into the design. Low power and high-power tests performed on various components of these LEDA systems and their results are presented here.

  11. Pressure distribution method for ex-situ evaluation of flow distribution in polymer electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Haase, S.; Mueller, S.

    2015-04-01

    Fuel cells for automotive applications consist of cells with large active areas. The active area is generally between 150 cm2 and 400 cm2. The reaction gases and the cooling media are distributed via bipolar plates to the reaction zones. Understanding local and cell wide gas distribution within the flow field at high current densities greater than 2.0 A/cm2 is a key factor regarding efficiency at low stoichiometry, lambda less than 2. In this paper a new method is introduced, which can be used as ex-situ evaluation of flow distribution. The gas pressure distribution is mapped with an array of 5 × 12 membrane differential pressure sensors by measuring the static pressure locally against the outlet pressure. Below a differential pressure of 100 mbar the signal measurement accuracy is ±2.5 mbar. This is demonstrated in a flow field with an active area of 250 cm2. The sensors are located next to the micro porous layer of the gas diffusion layer to avoid any impact of dynamic pressure. The effect of the intrusion of gas diffusion layer material into the flow channels on the fluid distribution is evaluated at clamping pressures between 0.6 MPa and 4.2 MPa.

  12. ESBWR enhanced flow distribution with optimized orificing and related fuel cycle performance

    SciTech Connect

    Pearson, G. J.; Karve, A. A.; Fawcett, R. M.

    2012-07-01

    The Economic Simplified Boiling Water Reactor (ESBWR) is GEH's latest Generation III+ reactor design with natural circulation coolant flow and passive safety features. Reliance on natural circulation as the sole means of core coolant driving force results in increased power-to-flow ratio and places increased importance on the efficient distribution of core flow in order to achieve optimum thermal margins and improved fuel cycle efficiency. In addition, the large core size of the ESBWR, containing 1132 bundles, greatly benefits from a more targeted distribution of flow, directing a higher fraction of flow to high power bundles in the 'ring of fire' region of typical BWR loading patterns and a lower fraction of flow to low power bundles on and near the core periphery. Desirable flow distributions can be achieved by modifying the hydraulic resistance of the inlet orifices to preferentially force flow to the targeted region. The inlet orifice is a feature that is incorporated into the fuel support piece of a typical BWR design. The majority of existing forced circulation BWR's rely on only two orifice types - a peripheral orifice located along the outermost row and a central orifice in all other locations. A more optimum distribution of core flow is achievable with the introduction of multiple inlet orifice types. Multi-zone orifice layouts comprised of two, three and four types have been evaluated for the ESBWR. An efficient radial distribution of flow can have a direct beneficial effect on the Minimum Critical Power Ratio (MCPR). An improved multi-zone orifice layout in the ESBWR has the potential of significantly increasing active flow in high power bundles. On average, this flow increase corresponds to a noteworthy MCPR improvement. Additional MCPR margin may be used to enhance operating flexibility and to achieve reduced fuel cycle costs over the plant lifetime. Combined with GNF's latest high performance fuel design for the ESBWR, GNF2E, and improved loading

  13. The nature and distribution of flowing features in a weakly karstified porous limestone aquifer

    NASA Astrophysics Data System (ADS)

    Maurice, L. D.; Atkinson, T. C.; Barker, J. A.; Williams, A. T.; Gallagher, A. J.

    2012-05-01

    SummaryThe nature and distribution of flowing features in boreholes in an area of approximately 400 km2 in a weakly karstic porous limestone aquifer (the Chalk) was investigated using single borehole dilution tests (SBDTs) and borehole imaging. One-hundred and twenty flowing features identified from SBDTs in 24 boreholes have densities which decrease from ∼0.3 m-1 near the water table to ∼0.07 m-1 at depths of more than 40 m below the water table; the average density is 0.20 m-1. There is some evidence of regional lithological control and borehole imaging of three boreholes indicated that most flowing features are associated with marls, hardgrounds and flints that may be developed at a more local scale. Borehole imaging also demonstrated that many flowing features are solutionally enlarged fractures, suggesting that even in carbonate aquifers where surface karst is developed on only a small scale, groundwater flow is still strongly influenced by dissolution. Fully connected solutional pathways can occur over 100s, sometimes 1000s of metres. However, conduits, tubules and fissures may not always be individually persistent along a flowpath, instead being connected together and also connected to unmodified fractures to create a relatively dense network of voids with variable apertures (<0.1 cm to >15 cm). Groundwater therefore moves along flowpaths made up of voids with varying shape and character. Local solutional development of fractures at significant depths below the surface suggests that mixing corrosion and in situ sources of acidity may contribute to solutional enhancement of fractures. The study demonstrates that single borehole dilution testing is a useful method of obtaining a large dataset of flowing features at catchment-regional scales. The Chalk is a carbonate aquifer with small-scale surface karst development and this study raises the question of whether other carbonate aquifers with small-scale surface karst have similar characteristics, and what

  14. Flow distribution in parallel microfluidic networks and its effect on concentration gradient.

    PubMed

    Guermonprez, Cyprien; Michelin, Sébastien; Baroud, Charles N

    2015-09-01

    The architecture of microfluidic networks can significantly impact the flow distribution within its different branches and thereby influence tracer transport within the network. In this paper, we study the flow rate distribution within a network of parallel microfluidic channels with a single input and single output, using a combination of theoretical modeling and microfluidic experiments. Within the ladder network, the flow rate distribution follows a U-shaped profile, with the highest flow rate occurring in the initial and final branches. The contrast with the central branches is controlled by a single dimensionless parameter, namely, the ratio of hydrodynamic resistance between the distribution channel and the side branches. This contrast in flow rates decreases when the resistance of the side branches increases relative to the resistance of the distribution channel. When the inlet flow is composed of two parallel streams, one of which transporting a diffusing species, a concentration variation is produced within the side branches of the network. The shape of this concentration gradient is fully determined by two dimensionless parameters: the ratio of resistances, which determines the flow rate distribution, and the Péclet number, which characterizes the relative speed of diffusion and advection. Depending on the values of these two control parameters, different distribution profiles can be obtained ranging from a flat profile to a step distribution of solute, with well-distributed gradients between these two limits. Our experimental results are in agreement with our numerical model predictions, based on a simplified 2D advection-diffusion problem. Finally, two possible applications of this work are presented: the first one combines the present design with self-digitization principle to encapsulate the controlled concentration in nanoliter chambers, while the second one extends the present design to create a continuous concentration gradient within an open flow

  15. Distributed Leadership and High-Stakes Testing: Examining the Relationship between Distributed Leadership and LEAP Scores

    ERIC Educational Resources Information Center

    Boudreaux, Wilbert

    2011-01-01

    Educational stakeholders are aware that school administration has become an incredibly intricate dynamic that is too complex for principals to handle alone. Test-driven accountability has made the already daunting task of school administration even more challenging. Distributed leadership presents an opportunity to explore increased leadership…

  16. Flow-distributed oscillations: Stationary chemical waves in a reacting flow

    NASA Astrophysics Data System (ADS)

    Kærn, Mads; Menzinger, Michael

    1999-10-01

    A recent prediction of stationary waves in open, reacting flows is experimentally verified. We show that stationary waves are generated by a mechanism whereby the flow carries a time-oscillating subelement, behaving like a batch reactor, through space while a fixed boundary condition at the inflow locks the phase of the oscillation. This mechanism can generate stationary patterns when all diffusion coefficients are equal. The experimental system is the ferroin-catalyzed Belousov-Zhabotinsky reaction in a tubular reactor, fed by the outflow of a continuous flow stirred tank reactor (CSTR). Parameter conditions are such that the concentrations are constant in the CSTR while they oscillate in the flow tube.

  17. Constructing Physical Heterogeneity in the Lab: Varying Permeability Distributions in Flow-through Column Experiments

    NASA Astrophysics Data System (ADS)

    Lewis, A. J.; Druhan, J. L.; Maher, K.

    2013-12-01

    A comprehensive understanding of how fluids flow through physically heterogeneous porous media is essential to the prediction of contaminant mobility and resource sustainability in groundwater systems. Although many analytical and numerical methods exist to quantify the effects of physical heterogeneity on permeability and reactivity, to date, very few studies have attempted to physically design a known type of heterogeneity within a system, observe the effects on reactive transport, and compare those results to numerical models. We have designed and implemented an experimental procedure to address the effects of physical heterogeneity on tracer propagation by building several cylindrical columns with different known geometries of variable permeability. In these fabricated systems we observe the effects of each permeability distribution on solute transport and reactivity. The experimental data are compared against simulated tracer breakthroughs from the reactive transport code Crunchflow, using analytical solutions for effective permeability based on the geometry of the column pack. We employ chemically homogeneous sand of two distinct grain size distributions to construct 10 cm diameter x 30 cm length cylindrical columns. The sand we use is ultra-high purity, nonreactive crystalline silica (SiO2). The coarse grain sand has a particle size distribution between 0.149-0.297 mm diameter and the fine grain between 0.074-0.149 mm diameter. A reference column consisting of a homogeneous pack of the coarse grain sand is contrasted with two columns utilizing both grain sizes. One column is constructed of an inner core of fine grain sand surrounded by an outer annulus of coarse grain sand, and a second is built with one hemisphere of fine grain and one hemisphere of coarse grand sand. The volumes of coarse and fine grain sand used in both heterogeneous columns are equal, and the porosity of the sands are 44% for the coarse grain and 42% for the fine grain. When packed into

  18. Distributed and Centralized Conflict Management Under Traffic Flow Management Constraints

    NASA Technical Reports Server (NTRS)

    Feron, Eric; Bilimoria, Karl (Technical Monitor)

    2001-01-01

    The past year's activity has concentrated on the following two activities: (1) Refining and completing our study on the stability of interacting flows of aircraft when they have to resolve conflicts in a decentralized and sequential manner. More specifically, it was felt that some of the modeling assumptions made during previous research (such offset maneuvering models) could be improved to include more realistic models such as heading changes when analyzing interacting flow stability problems. We extended our analysis to achieve this goal. The results of this study have been submitted for presentation at the 2002 American Control Conference; (2) Examining the issues associated with delay propagation across multiple enroute sectors. This study was initiated at NASA in cooperation with Dr. Karl Bilimoria. Considering a set of adjacent sectors, this ongoing study concentrates on the effect of various traffic flow management strategies on the propagation of delays and congestion across sectors. The problem description and findings so far are reported in the attached working paper "Enroute sector buffering capacity."

  19. Water flow controls distribution and feeding behavior of two co-occurring coral reef fishes: I. Field measurements

    NASA Astrophysics Data System (ADS)

    Finelli, C. M.; Clarke, R. D.; Robinson, H. E.; Buskey, E. J.

    2009-06-01

    The interaction of flowing water with reef topography creates a continuum of flow microhabitats that can alter species distributions directly via transport of organisms or propagules, or indirectly by modulating the availability of critical resources. To examine how water flow affects the distribution and feeding performance of two species of planktivorous tube blennies (Chaenopsidae), flow speed and turbulence were measured within the feeding areas of Acanthemblemaria spinosa and A. aspera at three sites within Glover’s Reef, Belize. Although co-occurring, A. spinosa occupies topographically high locations (e.g., upright coral skeletons) while A. aspera occupies topographically low shelters in the coral pavement. Boundary layer theory predicts that A. spinosa should experience higher flow (and a higher flux of planktonic food) relative to A. aspera; however, complex topography and oscillatory flow require that this prediction is tested directly in the field. Within each site, the flow experienced by A. spinosa was, indeed, faster and more turbulent than that experienced by A. aspera at site-specific intermediate wave heights. When waves were small, gentle velocity gradients produced similar flows for the two species. When waves were high, flow was uniformly fast through the water column due to thinning of the benthic boundary layer. Plankton availability was similar for the species, with the exception of a greater abundance of harpacticoid copepods at the shelters of A. aspera. Quantitative behavioral observations suggest that the foraging strategies employed by the two fishes exploit the prevailing hydrodynamic conditions. For example, A. spinosa, the stronger swimmer of the two, attacks nearly 100% of the time in the water column where it can exploit the higher flux of plankton associated with faster flows, while A. aspera attacks primarily toward the reef surface where currents are likely to be slower and it can exploit more abundant benthic prey.

  20. The Measurement of Pressure Through Tubes in Pressure Distribution Tests

    NASA Technical Reports Server (NTRS)

    Hemke, Paul E

    1928-01-01

    The tests described in this report were made to determine the error caused by using small tubes to connect orifices on the surface of aircraft to central pressure capsules in making pressure distribution tests. Aluminum tubes of 3/16-inch inside diameter were used to determine this error. Lengths from 20 feet to 226 feet and pressures whose maxima varied from 2 inches to 140 inches of water were used. Single-pressure impulses for which the time of rise of pressure from zero to a maximum varied from 0.25 second to 3 seconds were investigated. The results show that the pressure recorded at the capsule on the far end of the tube lags behind the pressure at the orifice end and experiences also a change in magnitude. For the values used in these tests the time lag and pressure change vary principally with the time of rise of pressure from zero to a maximum and the tube length. Curves are constructed showing the time lag and pressure change. Empirical formulas are also given for computing the time lag. Analysis of pressure distribution tests made on airplanes in flight shows that the recorded pressures are slightly higher than the pressures at the orifice and that the time lag is negligible. The apparent increase in pressure is usually within the experimental error, but in the case of the modern pursuit type of airplane the pressure increase may be 5 per cent. For pressure-distribution tests on airships the analysis shows that the time lag and pressure change may be neglected.

  1. PHYTOPLANKTON PRODUCTION AND NUTRIENT DISTRIBUTIONS IN A SUBTROPICAL ESTUARY: IMPORTANCE OF FRESHWATER FLOW

    EPA Science Inventory

    The relationships between phytoplankton productivity, nutrient distributions, and freshwater flow were examined in a seasonal study conducted in Escambia Bay, Florida, USA, located in the northeastern Gulf of Mexico. Five sites oriented along the salinity gradient were sampled 24...

  2. Columbia University Flow Instability Experimental Program, Volume 5: Single annulus tests, steady-state test program

    SciTech Connect

    Dougherty, T.; Maciuca, C.; McAssey, E.V. Jr.; Reddy, D.G.; Yang, B.W.

    1991-07-01

    This report presents results for the steady state portion of the finless single annulus test program. The objective of the experimental study was to investigate the onset of flow instability in an annular geometry similar to the MARK 22 reactor. The test program involved testing of both a finless or ribless heater and a ribbed heater. The latter program is currently underway and will be reported separately. For finless heater, testing was conducted in both a steady state and transient mode. The present report presents steady state results for a series of experiments with uniform and asymmetric heating. The demand curves obtained under uniform heating yielded OFI flow-rates which were slightly below those obtained for a circular tube geometry with the same L/D ratio; however, the single annulus had a hydraulic diameter which was approximately fifty percent larger than the circular tube. The asymmetric heating cases were selected to provide the same average power input as the uniform cases. The results for these tests indicated that the flow-rate at OFI increased with the degree of asymmetry.

  3. Testing for bimodality in frequency distributions of data suggesting polymorphisms of drug metabolism--hypothesis testing.

    PubMed Central

    Jackson, P R; Tucker, G T; Woods, H F

    1989-01-01

    1. The theory of methods of hypothesis testing in relation to the detection of bimodality in density distributions is discussed. 2. Practical problems arising from these methods are outlined. 3. The power of three methods of hypothesis testing was compared using simulated data from bimodal distributions with varying separation between components. None of the methods could determine bimodality until the separation between components was 2 standard deviation units and could only do so reliably (greater than 90%) when the separation was as great as 4-6 standard deviation units. 4. The robustness of a parametric and a non-parametric method of hypothesis testing was compared using simulated unimodal distributions known to deviate markedly from normality. Both methods had a high frequency of falsely indicating bimodality with distributions where the components had markedly differing variances. 5. A further test of robustness using power transformation of data from a normal distribution showed that the algorithms could accurately determine unimodality only when the skew of the distribution was in the range 0-1.45. PMID:2611088

  4. Jet array impingement flow distributions and heat transfer characteristics. Effects of initial crossflow and nonuniform array geometry

    NASA Astrophysics Data System (ADS)

    Florschuetz, L. W.; Metzger, D. E.; Su, C. C.; Isoda, Y.; Tseng, H. H.

    1982-11-01

    Two-dimensional arrays of circular air jets impinging on a heat transfer surface parallel to the jet orifice plate are considered. The jet flow, after impingement, is constrained to exit in a single direction along the channel formed by the jet orifice plate and the heat transfer surface. The configurations considered are intended to model those of interest in current and contemplated gas turbine airfoil midchord cooling applications. The effects of an initial crossflow which approaches the array through an upstream extension of the channel are considered. Flow distributions as well as heat transfer coefficients and adiabatic wall temperatures resolved to one streamwise hole spacing were measured as a function of the initial crossflow rate and temperature relative to the jet flow rate and temperature. Both Nusselt number profiles and dimensionless adiabatic wall temperature (effectiveness) profiles are presented and discussed. Special test results which show a significant reduction of jet orifice discharge coefficients owing to the effect of a confined crossflow are also presented, along with a flow distribution model which incorporates those effects. A nonuniform array flow distribution model is developed and validated.

  5. Pressure distributions and oil-flow patterns for a swept circulation-control wing

    NASA Technical Reports Server (NTRS)

    Keener, Earl R.; Sanderfer, Dwight T.; Wood, Norman J.

    1987-01-01

    Pressure distributions and photographs of oil flow patterns are presented for a circulation control wing. The model was an aspect ratio four semispan wing mounted on the side wall of the NASA Ames Transonic Wind Tunnel. The airfoil was a 20 percent thick ellipse, modified with circular leading and trailing edges of 4 percent radius, and had a 25.4 cm constant chord. This configuration does not represent a specific wing design, but is generic. A full span, tangetial, rearward blowing, circulation control slot was incorporated ahead of the trailing edge on the upper surface. The wing was tested at Mach numbers from 0.3 to 0.75 at sweep angle of 0 to 45 deg with internal to external pressure ratios of 1.0 to 3.0. Lift and pitching momemt coefficients were obtained from measured pressure distributions at five span stations. When the conventional corrections resulting from sweep angle are applied to the lift and moment of circulation control sections, no additional corrections are necessary to account for changes in blowing efficiency. This is demonstrated for an aft sweep angle of 45 deg. An empirical technique for estimating the downwash distribution of a swept wing was validated.

  6. Simulation based flow distribution network optimization for vacuum assisted resin transfer moulding process

    NASA Astrophysics Data System (ADS)

    Hsiao, Kuang-Ting; Devillard, Mathieu; Advani, Suresh G.

    2004-05-01

    In the vacuum assisted resin transfer moulding (VARTM) process, using a flow distribution network such as flow channels and high permeability fabrics can accelerate the resin infiltration of the fibre reinforcement during the manufacture of composite parts. The flow distribution network significantly influences the fill time and fill pattern and is essential for the process design. The current practice has been to cover the top surface of the fibre preform with the distribution media with the hope that the resin will flood the top surface immediately and penetrate through the thickness. However, this approach has some drawbacks. One is when the resin finds its way to the vent before it has penetrated the preform entirely, which results in a defective part or resin wastage. Also, if the composite structure contains ribs or inserts, this approach invariably results in dry spots. Instead of this intuitive approach, we propose a science-based approach to design the layout of the distribution network. Our approach uses flow simulation of the resin into the network and the preform and a genetic algorithm to optimize the flow distribution network. An experimental case study of a co-cured rib structure is conducted to demonstrate the design procedure and validate the optimized flow distribution network design. Good agreement between the flow simulations and the experimental results was observed. It was found that the proposed design algorithm effectively optimized the flow distribution network of the part considered in our case study and hence should prove to be a useful tool to extend the VARTM process to manufacture of complex structures with effective use of the distribution network layup.

  7. Models, assumptions, and experimental tests of flows near magnetized boundaries

    NASA Astrophysics Data System (ADS)

    Siddiqui, M. Umair

    2015-11-01

    We present a history of research on the magnetized plasma boundary and recent first measurements of particle flows in such structures in laboratory plasmas using multi-dimensional laser-induced fluorescence (LIF). Our measurements show that the canonical model for this boundary proposed in 1982 [Chodura, Phys. Fluids (1982)] is inaccurate for systems where the ion-neutral collision length is less than at least 4 times the ion gyro radius. Rather, our measurements validate more sophisticated plasma boundary fluid models that take neutral collisions into account [Riemann, Phys. Plasmas (1994); Ahedo, Phys. Plasmas (1997); Siddiqui et al., Phys. Plasmas (2014)]. In light of these results, we show that both three-dimensional ion and neutral velocity distribution functions are strongly affected near the boundary. We discuss effects of these perturbed distributions on wall loading and erosion in experiments and applications such as divertor tokamak scrape-off layers and Hall thrusters. Finally, we propose modern definitions of the oft-used term, ``magnetic presheath.'' This work is supported by U.S. National Science Foundation grant number PHY-1360278.

  8. Detailed computational procedure for design of cascade blades with prescribed velocity distributions in compressible potential flows

    NASA Technical Reports Server (NTRS)

    Costello, George R; Cummings, Robert L; Sinnette, John T , Jr

    1952-01-01

    A detailed step-by-step computational outline is presented for the design of two-dimensional cascade blades having a prescribed velocity distribution on the blade in a potential flow of the usual compressible fluid. The outline is based on the assumption that the magnitude of the velocity in the flow of the usual compressible nonviscous fluid is proportional to the magnitude of the velocity in the flow of a compressible nonviscous fluid with linear pressure-volume relation.

  9. Electrophoretic sample insertion. [device for uniformly distributing samples in flow path

    NASA Technical Reports Server (NTRS)

    Mccreight, L. R. (Inventor)

    1974-01-01

    Two conductive screens located in the flow path of an electrophoresis sample separation apparatus are charged electrically. The sample is introduced between the screens, and the charge is sufficient to disperse and hold the samples across the screens. When the charge is terminated, the samples are uniformly distributed in the flow path. Additionally, a first separation by charged properties has been accomplished.

  10. Flow distribution and maximum current density studies in redox flow batteries with a single passage of the serpentine flow channel

    NASA Astrophysics Data System (ADS)

    Ke, Xinyou; Alexander, J. Iwan D.; Prahl, Joseph M.; Savinell, Robert F.

    2014-12-01

    Flow batteries show promise for very large-scale stationary energy storage such as needed for the grid and renewable energy implementation. In recent years, researchers and developers of redox flow batteries (RFBs) have found that electrode and flow field designs of PEM fuel cell (PEMFC) technology can increase the power density and consequently push down the cost of flow battery stacks. In this paper we present a macroscopic model of a typical PEMFC-like RFB electrode-flow field design. The model is a layered system comprised of a single passage of a serpentine flow channel and a parallel underlying porous electrode (or porous layer). The effects of the inlet volumetric flow rate, permeability of the porous layer, thickness of the porous layer and thickness of the flow channel on the flow penetration into the porous layer are investigated. The maximum current density corresponding to stoichiometry is estimated to be 377 mA cm-2 and 724 mA cm-2, which compares favorably with experiments of ∼400 mA cm-2 and ∼750 mA cm-2, for a single layer and three layers of the carbon fiber paper, respectively.

  11. Stress distribution in composite flatwise tension test specimens

    NASA Technical Reports Server (NTRS)

    Scott, Curtis A.; Pereira, J. Michael

    1993-01-01

    A finite element analysis was conducted to determine the stress distribution in typical graphite/epoxy composite flat wise tension (FWT) specimens under normal loading conditions. The purpose of the analysis was to determine the relationship between the applied load and the stress in the sample to evaluate the validity of the test as a means of measuring the out-of-plane strength of a composite laminate. Three different test geometries and three different material lay ups were modeled. In all cases, the out-of-plane component of stress in the test section was found to be uniform, with no stress concentrations, and very close to the nominal applied stress. The stress in the sample was found to be three-dimensional, and the magnitude of in-plane normal and shear stresses varied with the anisotropy of the test specimen. However, in the cases considered here, these components of stress were much smaller than the out-of-plane normal stress. The geometry of the test specimen had little influence on the results. It was concluded that the flat wise tension test provides a good measure of the out-of-plane strength for the representative materials that were studied.

  12. 42 CFR 84.93 - Gas flow test; open-circuit apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Gas flow test; open-circuit apparatus. 84.93...-Contained Breathing Apparatus § 84.93 Gas flow test; open-circuit apparatus. (a) A static-flow test will be...) water-column height when full container pressure is applied. (c) Where pressure demand apparatus...

  13. 42 CFR 84.93 - Gas flow test; open-circuit apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Gas flow test; open-circuit apparatus. 84.93...-Contained Breathing Apparatus § 84.93 Gas flow test; open-circuit apparatus. (a) A static-flow test will be...) water-column height when full container pressure is applied. (c) Where pressure demand apparatus...

  14. 42 CFR 84.93 - Gas flow test; open-circuit apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Gas flow test; open-circuit apparatus. 84.93...-Contained Breathing Apparatus § 84.93 Gas flow test; open-circuit apparatus. (a) A static-flow test will be...) water-column height when full container pressure is applied. (c) Where pressure demand apparatus...

  15. 30 CFR 75.152 - Tests of air flow; qualified person.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests of air flow; qualified person. 75.152....152 Tests of air flow; qualified person. A person is a qualified person within the meaning of the provisions of Subpart D—Ventilation of this part requiring that tests of air flow be made by a...

  16. Multiple well-shutdown tests and site-scale flow simulation in fractured rocks.

    PubMed

    Tiedeman, Claire R; Lacombe, Pierre J; Goode, Daniel J

    2010-01-01

    A new method was developed for conducting aquifer tests in fractured-rock flow systems that have a pump-and-treat (P&T) operation for containing and removing groundwater contaminants. The method involves temporary shutdown of individual pumps in wells of the P&T system. Conducting aquifer tests in this manner has several advantages, including (1) no additional contaminated water is withdrawn, and (2) hydraulic containment of contaminants remains largely intact because pumping continues at most wells. The well-shutdown test method was applied at the former Naval Air Warfare Center (NAWC), West Trenton, New Jersey, where a P&T operation is designed to contain and remove trichloroethene and its daughter products in the dipping fractured sedimentary rocks underlying the site. The detailed site-scale subsurface geologic stratigraphy, a three-dimensional MODFLOW model, and inverse methods in UCODE_2005 were used to analyze the shutdown tests. In the model, a deterministic method was used for representing the highly heterogeneous hydraulic conductivity distribution and simulations were conducted using an equivalent porous media method. This approach was very successful for simulating the shutdown tests, contrary to a common perception that flow in fractured rocks must be simulated using a stochastic or discrete fracture representation of heterogeneity. Use of inverse methods to simultaneously calibrate the model to the multiple shutdown tests was integral to the effectiveness of the approach. PMID:20002208

  17. Groundwater Flow Systems at the Nevada Test Site, Nevada: A Synthesis of Potentiometric Contours, Hydrostratigraphy, and Geologic Structures

    SciTech Connect

    Fenelon, Joseph M.; Sweetkind, Donald S.; Laczniak, Randell J.

    2010-01-25

    Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial-volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial-volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial-volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic

  18. Groundwater Flow Systems at the Nevada Test Site, Nevada: A Synthesis of Potentiometric Contours, Hydrostratigraphy, and Geologic Structures

    USGS Publications Warehouse

    Fenelon, Joseph M.; Sweetkind, Donald S.; Laczniak, Randell J.

    2010-01-01

    Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial-volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial-volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial-volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic

  19. Evaluation of Spatial Pattern of Altered Flow Regimes on a River Network Using a Distributed Hydrological Model.

    PubMed

    Ryo, Masahiro; Iwasaki, Yuichi; Yoshimura, Chihiro; Saavedra V, Oliver C

    2015-01-01

    Alteration of the spatial variability of natural flow regimes has been less studied than that of the temporal variability, despite its ecological importance for river ecosystems. Here, we aimed to quantify the spatial patterns of flow regime alterations along a river network in the Sagami River, Japan, by estimating river discharge under natural and altered flow conditions. We used a distributed hydrological model, which simulates hydrological processes spatiotemporally, to estimate 20-year daily river discharge along the river network. Then, 33 hydrologic indices (i.e., Indicators of Hydrologic Alteration) were calculated from the simulated discharge to estimate the spatial patterns of their alterations. Some hydrologic indices were relatively well estimated such as the magnitude and timing of maximum flows, monthly median flows, and the frequency of low and high flow pulses. The accuracy was evaluated with correlation analysis (r > 0.4) and the Kolmogorov-Smirnov test (α = 0.05) by comparing these indices calculated from both observed and simulated discharge. The spatial patterns of the flow regime alterations varied depending on the hydrologic indices. For example, both the median flow in August and the frequency of high flow pulses were reduced by the maximum of approximately 70%, but these strongest alterations were detected at different locations (i.e., on the mainstream and the tributary, respectively). These results are likely caused by different operational purposes of multiple water control facilities. The results imply that the evaluation only at discharge gauges is insufficient to capture the alteration of the flow regime. Our findings clearly emphasize the importance of evaluating the spatial pattern of flow regime alteration on a river network where its discharge is affected by multiple water control facilities. PMID:26207997

  20. Evaluation of Spatial Pattern of Altered Flow Regimes on a River Network Using a Distributed Hydrological Model

    PubMed Central

    Ryo, Masahiro; Iwasaki, Yuichi; Yoshimura, Chihiro; Saavedra V., Oliver C.

    2015-01-01

    Alteration of the spatial variability of natural flow regimes has been less studied than that of the temporal variability, despite its ecological importance for river ecosystems. Here, we aimed to quantify the spatial patterns of flow regime alterations along a river network in the Sagami River, Japan, by estimating river discharge under natural and altered flow conditions. We used a distributed hydrological model, which simulates hydrological processes spatiotemporally, to estimate 20-year daily river discharge along the river network. Then, 33 hydrologic indices (i.e., Indicators of Hydrologic Alteration) were calculated from the simulated discharge to estimate the spatial patterns of their alterations. Some hydrologic indices were relatively well estimated such as the magnitude and timing of maximum flows, monthly median flows, and the frequency of low and high flow pulses. The accuracy was evaluated with correlation analysis (r > 0.4) and the Kolmogorov–Smirnov test (α = 0.05) by comparing these indices calculated from both observed and simulated discharge. The spatial patterns of the flow regime alterations varied depending on the hydrologic indices. For example, both the median flow in August and the frequency of high flow pulses were reduced by the maximum of approximately 70%, but these strongest alterations were detected at different locations (i.e., on the mainstream and the tributary, respectively). These results are likely caused by different operational purposes of multiple water control facilities. The results imply that the evaluation only at discharge gauges is insufficient to capture the alteration of the flow regime. Our findings clearly emphasize the importance of evaluating the spatial pattern of flow regime alteration on a river network where its discharge is affected by multiple water control facilities. PMID:26207997

  1. Design, testing and two-dimensional flow modeling of a multiple-disk fan

    SciTech Connect

    Engin, Tahsin; Oezdemir, Mustafa; Cesmeci, Sevki

    2009-11-15

    A multiple-disk Tesla type fan has been designed, tested and analyzed two-dimensionally using the conservation of angular momentum principle. Experimental results showed that such multiple-disk fans exhibited exceptionally low performance characteristics, which could be attributed to the low viscosity, tangential nature of the flow, and large mechanical energy losses at both suction and discharge sections that are comparable to the total input power. By means of theoretical analysis, local and overall shearing stresses on the disk surfaces have been determined based on tangential and radial velocity distributions of the air flow of different volume flow rates at prescribed disk spaces and rotational speeds. Then the total power transmitted by rotating disks to air flow, and the power acquired by the air flow in the gap due to transfer of angular momentum have been obtained by numerically integrating shearing stresses over the disk surfaces. Using the measured shaft and hydraulic powers, these quantities were utilized to evaluate mechanical energy losses associated with the suction and discharge sections of the fan. (author)

  2. Drainflow: a fully distributed integrated surface/subsurface flow model for drainage studies

    NASA Astrophysics Data System (ADS)

    Shokri, Ali; Bardsley, William Earl

    2015-04-01

    The scale of drainage studies may vary from high-resolution small scale investigations through to comprehensive catchment or regional-scale studies. This wide range of scales poses a significant challenge for the development of a suitable drainage model. To meet this demand, a fully distributed surface/subsurface interactive flow model named henceforth Drainflow has been developed. Drainflow includes both the Saint Venant equations for surface flow components and the Richards equation for saturated and unsaturated zones. To develop the model, surface and subsurface flow modules are formulated separately, then each component is connected to the other parts. All modules simultaneously interact to calculate water level and discharge in tile drains, channel networks, and overland flow. In the subsurface domain, the model also yields soil moisture and water table elevation. A smoothed Heaviside function is introduced to give a continuous transition of the model between Dirichlet and Neumann boundary conditions for tile drains and surface/subsurface flow interface boundaries. Compared to traditional drainage studies, Drainflow has the advantage of estimating the land surface recharge (LSR) directly from the partial differential Richards equation rather than via an analytical or empirical drainage method like the Green and Ampt equation. To test the model's accuracy, comparisons are made between Drainflow and a range of surface/subsurface flow models for five published integrated surface and subsurface problems. The comparison indicates Drainflow has a reasonably good agreement with the other integrated models. Furthermore, it is shown that the smoothed Heaviside functions technique is a very effective method to overcome the non-linearity problem created from switching between dry and wet boundary conditions. In addition, Drainflow was run for some drainage study examples and was found to be fairly flexible in terms of changing all or part of the model dimensions as

  3. Experimental Testing and Modeling Analysis of Solute Mixing at Water Distribution Pipe Junctions

    EPA Science Inventory

    Flow dynamics at a pipe junction controls particle trajectories, solute mixing and concentrations in downstream pipes. Here we have categorized pipe junctions into five hydraulic types, for which flow distribution factors and analytical equations for describing the solute mixing ...

  4. Effect of horizontal heat and fluid flow on the vertical temperature distribution in a semiconfining layer

    USGS Publications Warehouse

    Lu, N.; Ge, S.

    1996-01-01

    By including the constant flow of heat and fluid in the horizontal direction, we develop an analytical solution for the vertical temperature distribution within the semiconfining layer of a typical aquifer system. The solution is an extension of the previous one-dimensional theory by Bredehoeft and Papadopulos [1965]. It provides a quantitative tool for analyzing the uncertainty of the horizontal heat and fluid flow. The analytical results demonstrate that horizontal flow of heat and fluid, if at values much smaller than those of the vertical, has a negligible effect on the vertical temperature distribution but becomes significant when it is comparable to the vertical.

  5. Age distributions and dynamically changing hydrologic systems: Exploring topography-driven flow

    NASA Astrophysics Data System (ADS)

    Gomez, J. D.; Wilson, J. L.

    2013-03-01

    Natural systems are driven by dynamic forcings that change in time as well as space, behavior that is inherited by the system flow field and results in time-varying age distributions (ADs). This work presents a review of the mathematical tools and solution approaches used to model ADs in dynamic time-varying flow systems. A simple conceptual, numerical model is then used to explore the role of flow dynamics in ADs for topography-driven flow systems. This model is an analog for regional groundwater systems and hyporheic zones. This model demonstrates that relatively small fluctuations in the forcing, even though importantly affecting the flow in the system, can have minimal effects in ADs. However, as the intensity of fluctuation increases, still within the bounds observed in natural systems, ADs in shallow parts of the system become highly sensitive to dynamic flow conditions, leading to considerable changes in the moments and modality of the distributions with time. In particular, transient flow can lead to emergence of new modes in the AD, which would not be present under steady flow conditions. The discrepancy observed between ADs under steady and transient flow conditions is explained by enhancement of mixing due to temporal variations in the flow field. ADs in deeper parts of the system are characterized by multimodality and tend to be more stable over time even for large forcing fluctuations.

  6. Curved flow wind tunnnel test of F-18 aircraft

    NASA Technical Reports Server (NTRS)

    Lutze, F. H.

    1980-01-01

    The curved flow capability of a stability wind tunnel was used to investigate the lateral directional characteristics of an F-18 aircraft. The model is described and the procedures used to obtain and correct the data and a graphical presentation of the results are presented. The results include graphs of lateral directional derivatives versus sideslip or static plots, the lateral directional static stability derivatives versus angle of attack, and finally the lateral directional derivatives versus nondimensional yaw rate for different angles of attack and sideslip. Results are presented for several configurations including complete, complete without vertical tails, complete without horizontal tails, fuselage wing and fuselage alone. Each of these were tested with and without wing leading edge extensions.

  7. In situ potential distribution measurement in an all-vanadium flow battery.

    PubMed

    Liu, Qinghua; Turhan, Ahmet; Zawodzinski, Thomas A; Mench, Matthew M

    2013-07-18

    An experimental method for measurement of local redox potential within multilayer electrodes was developed and applied to all-vanadium redox flow batteries (VRFBs). Through-plane measurement at the positive side reveals several important phenomena including potential distribution, concentration distribution of active species and the predominant reaction location within the porous carbon electrodes. PMID:23736771

  8. Aeroacoustic Characteristics of Model Jet Test Facility Flow Conditioners

    NASA Technical Reports Server (NTRS)

    Kinzie, Kevin W.; Henderson, Brenda S.; Haskin, Harry H.

    2005-01-01

    An experimental investigation of flow conditioning devices used to suppress internal rig noise in high speed, high temperature experimental jet facilities is discussed. The aerodynamic and acoustic characteristics of a number of devices including pressure loss and extraneous noise generation are measured. Both aerodynamic and acoustic characteristics are strongly dependent on the porosity of the flow conditioner and the closure ratio of the duct system. For unchoked flow conditioners, the pressure loss follows conventional incompressible flow models. However, for choked flow conditioners, a compressible flow model where the duct and flow conditioner system is modeled as a convergent-divergent nozzle can be used to estimate pressure loss. Choked flow conditioners generate significantly more noise than unchoked conditioners. In addition, flow conditioners with small hole diameters or sintered metal felt material generate less self-noise noise compared to flow conditioners with larger holes.

  9. Hybrid laminar flow control tests in the Boeing Research Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Parikh, P. G.; Lund, D. W.; George-Falvy, D.; Nagel, A. L.

    1990-01-01

    The hybrid laminar flow control (HLFC) concept has undergone wind tunnel testing at near full-scale Reynolds number on an infinite wing of 30-deg sweep on which boundary-layer suction was furnished over the first 20 percent of chord of the upper surface. Depending on the external pressure distribution, the HLFC extended the laminarity of the boundary layer as far back as 45 percent of chord; this corresponds to a transition Reynolds number of about 11 million. The maximum chordwise extent of laminar run was found to be insensitive to the suction level over a wide range.

  10. Effects of cord compression on fetal blood flow distribution and O/sub 2/ delivery

    SciTech Connect

    Itskovitz, J.; LaGamma, E.F.; Rudolph, A.M.

    1987-01-01

    The authors used the radionuclide microsphere technique in nine fetal lambs to examine the effect of partial cord compression on distribution of cardiac output and O/sub 2/ delivery to fetal organs and venous flow patterns. With a 50% reduction in umbilical blood flow the fraction of fetal cardiac output distributed to the brain, heart, carcass, kidneys, and gastrointestinal tract increased. Pulmonary blood flow fell. O/sub 2/ delivery to the brain and myocardium was maintained but was reduced to peripheral, renal, and gastrointestinal circulations. Hepatic blood flow decreased and O/sub 2/ delivery fell by 75%. The proportion of umbilical venous blood passing through the ductus venosus increased from 43.9 to 71.8%. The preferential distribution of ductus venosus blood flow through the foramen ovale was enhanced and the proportion of O/sub 2/ delivery to upper body organs derived from the ductus venosus increased. Abdominal inferior vena caval blood flow increased, and it was also preferentially distributed through the foramen ovale and constituted the major fraction of the arterial blood supply to the upper body organs. Thus cord compression modified the distribution of cardiac output and the patterns of venous returns in the fetus. This pattern of circulatory response differs from that observed with other causes of reduced O/sub 2/ delivery.

  11. Blood flow distribution in an anatomically detailed arterial network model: criteria and algorithms.

    PubMed

    Blanco, Pablo J; Watanabe, Sansuke M; Dari, Enzo A; Passos, Marco Aurélio R F; Feijóo, Raúl A

    2014-11-01

    Development of blood flow distribution criteria is a mandatory step toward developing computational models and numerical simulations of the systemic circulation. In the present work, we (i) present a systematic approach based on anatomical and physiological considerations to distribute the blood flow in a 1D anatomically detailed model of the arterial network and (ii) develop a numerical procedure to calibrate resistive parameters in terminal models in order to effectively satisfy such flow distribution. For the first goal, we merge data collected from the specialized medical literature with anatomical concepts such as vascular territories to determine blood flow supply to specific (encephalon, kidneys, etc.) and distributed (muscles, skin, etc.) organs. Overall, 28 entities representing the main specific organs are accounted for in the detailed description of the arterial topology that we use as model substrate. In turn, 116 vascular territories are considered as the basic blocks that compose the distributed organs throughout the whole body. For the second goal, Windkessel models are used to represent the peripheral beds, and the values of the resistive parameters are computed applying a Newton method to a parameter identification problem to guarantee the supply of the correct flow fraction to each terminal location according to the given criteria. Finally, it is shown that, by means of the criteria developed, and for a rather standard set of model parameters, the model predicts physiologically realistic pressure and flow waveforms. PMID:24682727

  12. Controls on the distribution and isotopic composition of helium in deep ground-water flows

    USGS Publications Warehouse

    Zhao, X.; Fritzel, T.L.B.; Quinodoz, H.A.M.; Bethke, C.M.; Torgersen, T.

    1998-01-01

    The distribution and isotopic composition of helium in sedimentary basins can be used to interpret the ages of very old ground waters. The piston-flow model commonly used in such interpretation, how ever, does not account for several important factors and as such works well only in very simple flow regimes. In this study of helium transport in a hypothetical sedimentary basin, we develop a numerical model that accounts for the magnitude and distribution of the basal helium flux, hydrodynamic dispersion, and complexities in flow regimes such as subregional flow cells. The modeling shows that these factors exert strong controls on the helium distribution and isotopic composition. The simulations may provide a basis for more accurate interpretations of observed helium concentrations and isotopic ratios in sedimentary basins.

  13. Performance and test section flow characteristics of the National Full-Scale Aerodynamics Complex 80- by 120-Foot Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Zell, Peter T.

    1993-01-01

    Results from the performance and test section flow calibration of the 80- by 120-Foot Wind Tunnel are presented. Measurements indicating the 80- by 120-ft test section flow quality were obtained throughout the tunnel operational envelope and for atmospheric wind speeds up to approximately 20 knots. Tunnel performance characteristics and a dynamic pressure system calibration were also documented during the process of mapping the test section flow field. Experimental results indicate that the test section flow quality is relatively insensitive to dynamic pressure and the level of atmospheric winds experienced during the calibration. The dynamic pressure variation in the test section is within +/-75 percent of the average. The axial turbulence intensity is less than 0.5 percent up to the maximum test section speed of 100 knots, and the vertical and lateral flow angle variations are within +/-5 deg and +/-7 deg, respectively. Atmospheric winds were found to affect the pressure distribution in the test section only at high ratios of wind speed to test section speed.

  14. Distribution of gas flow in internally manifolded solid oxide fuel-cell stacks

    NASA Astrophysics Data System (ADS)

    Boersma, R. J.; Sammes, N. M.

    In internally manifolded fuel-cell stacks, there is a non-uniform gas flow distribution along the height of the system. To gain an insight into this distribution an analytical model has been developed. In the model, the stack is viewed as a network of hydraulic resistances. Some of these resistances are constant, while some depend upon the gas velocity and can be determined from the literature. The model consists of equations for the network with counter-current flow in the manifold channels. Only the most important resistances are included, i.e., the resistances due to splitting and combining the flows in the manifold channels, and the resistance in the gas channels of the active cell area. The ratio between the average flow and the flow in the upper cell can be solved from the model. In this manner, a very useful tool for separatorplate design is obtained.

  15. Study of flow distribution and its improvement on the header of plate-fin heat exchanger

    NASA Astrophysics Data System (ADS)

    Wen, Jian; Li, Yanzhong

    2004-11-01

    In order to enhance the uniformity of flow distribution, an improved header configuration of plate-fin heat exchanger is put forward in this paper. Based on the analysis of the fluid flow maldistribution for the conventional header used in industry, a baffle with small holes of three different kinds of diameters is recommended to install in the header. The flow maldistribution parameter S is obtained under different header configuration. When the baffle is properly installed with an optimum length, with stagger arranged and suitably distributed holes from axial line to baffle boundary, the ratio of the maximum flow velocity to the minimum flow velocity drops from 3.44-3.04 to 1.57-1.68 for various Reynolds numbers. The numerical results indicate that the improved header configuration can effectively improve the performance. The conclusion of this paper is of great significance in the improvement of plate-fin heat exchanger.

  16. Testing the Pareto against the lognormal distributions with the uniformly most powerful unbiased test applied to the distribution of cities.

    PubMed

    Malevergne, Yannick; Pisarenko, Vladilen; Sornette, Didier

    2011-03-01

    Fat-tail distributions of sizes abound in natural, physical, economic, and social systems. The lognormal and the power laws have historically competed for recognition with sometimes closely related generating processes and hard-to-distinguish tail properties. This state-of-affair is illustrated with the debate between Eeckhout [Amer. Econ. Rev. 94, 1429 (2004)] and Levy [Amer. Econ. Rev. 99, 1672 (2009)] on the validity of Zipf's law for US city sizes. By using a uniformly most powerful unbiased (UMPU) test between the lognormal and the power-laws, we show that conclusive results can be achieved to end this debate. We advocate the UMPU test as a systematic tool to address similar controversies in the literature of many disciplines involving power laws, scaling, "fat" or "heavy" tails. In order to demonstrate that our procedure works for data sets other than the US city size distribution, we also briefly present the results obtained for the power-law tail of the distribution of personal identity (ID) losses, which constitute one of the major emergent risks at the interface between cyberspace and reality. PMID:21517562

  17. Testing the Pareto against the lognormal distributions with the uniformly most powerful unbiased test applied to the distribution of cities

    NASA Astrophysics Data System (ADS)

    Malevergne, Yannick; Pisarenko, Vladilen; Sornette, Didier

    2011-03-01

    Fat-tail distributions of sizes abound in natural, physical, economic, and social systems. The lognormal and the power laws have historically competed for recognition with sometimes closely related generating processes and hard-to-distinguish tail properties. This state-of-affair is illustrated with the debate between Eeckhout [Amer. Econ. Rev.SCIEAS0002-828210.1257/0002828043052303 94, 1429 (2004)] and Levy [Amer. Econ. Rev.SCIEAS0002-828210.1257/aer.99.4.1672 99, 1672 (2009)] on the validity of Zipf’s law for US city sizes. By using a uniformly most powerful unbiased (UMPU) test between the lognormal and the power-laws, we show that conclusive results can be achieved to end this debate. We advocate the UMPU test as a systematic tool to address similar controversies in the literature of many disciplines involving power laws, scaling, “fat” or “heavy” tails. In order to demonstrate that our procedure works for data sets other than the US city size distribution, we also briefly present the results obtained for the power-law tail of the distribution of personal identity (ID) losses, which constitute one of the major emergent risks at the interface between cyberspace and reality.

  18. Mechanistic model for void distribution in flashing flow

    SciTech Connect

    Riznic, J.; Ishii, M.; Afgan, N.

    1987-01-01

    A problem of discharging of an initially subcooled liquid from a high pressure condition into a low pressure environment is quite important in several industrial systems such as nuclear reactors and chemical reactors. A new model for the flashing process is proposed here based on the wall nucleation theory, bubble growth model and drift-flux bubble transport model. In order to calculate the bubble number density, the bubble number transport equation with a distributed source from the wall nucleation sites is used. The model predictions in terms of the void fraction are compared to Moby Dick and BNL experimental data. It shows that satisfactory agreements could be obtained from the present model without any floating parameter to be adjusted with data. This result indicates that, at least for the experimental conditions considered here, the mechanistic prediction of the flashing phenomenon is possible based on the present wall nucleation based model. 43 refs., 4 figs.

  19. Mechanistic model for void distribution in flashing flow

    NASA Astrophysics Data System (ADS)

    Riznic, J.; Ishii, M.; Afgan, N.

    A problem of discharging of an initially subcooled liquid from a high pressure condition into a low pressure environment is quite important in several industrial systems such as nuclear reactors and chemical reactors. A new model for the flashing process is proposed here based on the wall nucleation theory, bubble growth model and drift-flux bubble transport model. In order to calculate the bubble number density, the bubble number transport equation with a distributed source from the wall nucleation sites is used. The model predictions in terms of the void fraction are compared to Moby Dick and BNL experimental data. It shows that satisfactory agreements could be obtained from the present model without any floating parameter to be adjusted with data. This result indicates that, at least for the experimental conditions considered here, the mechanistic prediction of the flashing phenomenon is possible based on the present wall nucleation based model.

  20. A consistent model for fluid distribution, viscosity distribution, and flow-thermal structure in subduction zone

    NASA Astrophysics Data System (ADS)

    Horiuchi, Shun-suke; Iwamori, Hikaru

    2016-05-01

    Water plays crucial roles in the subduction zone dynamics affecting the thermal-flow structure through the fluid processes. We aim to understand what controls the dynamics and construct a model to solve consistently fluid generation, fluid transport, its reaction with the solid and resultant viscosity, and thermal-flow structure. We highlight the effect of mechanical weakening of rocks associated with hydration. The viscosity of serpentinite (ηserp) in subduction zones critically controls the flow-thermal structure via extent of mechanical coupling between the subducting slab and overlying mantle wedge. When ηserp is greater than 1021 Pa s, the thermal-flow structure reaches a steady state beneath the volcanic zone, and the melting region expands until Cin (initial water content in the subducting oceanic crust) reaches 3 wt %, and it does not expand from 3 wt %. On the other hand, when ηserp is less than 1019 Pa s, the greater water dependence of viscosity (expressed by a larger fv) confines a hot material to a narrower channel intruding into the wedge corner from a deeper part of the back-arc region. Consequently, the overall heat flux becomes less for a larger fv. When ageba (age of back-arc basin as a rifted lithosphere) = 7.5 Ma, the increase in fv weakens but shifts the melting region toward the trench side because of the narrow channel flow intruding into the wedge corner, where as it shuts down melting when ageba=20 Ma. Several model cases (particularly those with ηserp=1020 to 1021 Pa s and a relatively large fv for Cin=2 to 3 wt %) broadly account for the observations in the Northeast Japan arc (i.e., location and width of volcanic chain, extent of serpentinite, surface heat flow, and seismic tomography), although the large variability of surface heat flow and seismic tomographic images does not allow us to constrain the parameter range tightly.

  1. Distributed Hypothesis Testing With Social Learning and Symmetric Fusion

    NASA Astrophysics Data System (ADS)

    Rhim, Joong Bum; Goyal, Vivek K.

    2014-12-01

    We study the utility of social learning in a distributed detection model with agents sharing the same goal: a collective decision that optimizes an agreed upon criterion. We show that social learning is helpful in some cases but is provably futile (and thus essentially a distraction) in other cases. Specifically, we consider Bayesian binary hypothesis testing performed by a distributed detection and fusion system, where all decision-making agents have binary votes that carry equal weight. Decision-making agents in the team sequentially make local decisions based on their own private signals and all precedent local decisions. It is shown that the optimal decision rule is not affected by precedent local decisions when all agents observe conditionally independent and identically distributed private signals. Perfect Bayesian reasoning will cancel out all effects of social learning. When the agents observe private signals with different signal-to-noise ratios, social learning is again futile if the team decision is only approved by unanimity. Otherwise, social learning can strictly improve the team performance. Furthermore, the order in which agents make their decisions affects the team decision.

  2. Cinematics and sticking of heart valves in pulsatile flow test.

    PubMed

    Köhler, J; Wirtz, R

    1991-05-01

    The aim of the project was to develop laboratory test devices for studies of the cinematics and sticking behaviour of technical valve protheses. The second step includes testing technical valves of different types and sizes under static and dynamic conditions. A force-deflection balance was developed in order to load valve rims by static radial forces until sticking or loss of a disc (sticking- and clamping-mould point) with computer-controlled force deflection curves. A second deflection device was developed and used for prosthetic valves in the aortic position of a pulsatile mock circulation loop with simultaneous video-cinematography. The stiffness of technical valve rims varied between 0.20 (St. Jude) and about 1.0 N/micron (metal rim valves). The stiffness decreased significantly with increasing valve size. Sticking under pulsatile flow conditions was in good agreement with the static deflection measurements. Hence, valve sticking with increasing danger of thrombus formation is more likely with a less stiff valve rim. In the case of forces acting perpendicularly to the pendulum axis, the clamping mould-point of the valve can be reached, followed by disc dislodgement. PMID:1864654

  3. Two phase liquid helium flow testing to simulate the operation of a cryocondensation pump in the D3-D tokamak

    NASA Astrophysics Data System (ADS)

    Laughon, G. J.; Baxi, C. B.; Campbell, G. L.; Mahdavi, M. A.; Makariou, C. C.; Smith, J. P.; Schaffer, M. J.; Schaubel, K. M.; Menon, M. M.

    1994-06-01

    A liquid helium-cooled cryocondensation pump has been installed in the D3-D tokamak fusion energy research experiment at General Atomics. The pump is located within the tokamak vacuum chamber beneath the divertor baffle plates and is utilized for plasma density and contamination control. Two-phase helium flows through the pump at 5 to 10 g/s utilizing the heat transfer and constant temperature characteristics of boiling liquid . helium. The pump is designed for a pumping speed of 32,000 1/s. Extensive testing was performed with a prototypical pump test fixture. Several pump geometries (simple tube, coaxial flow plug, and coaxial slotted insert) were tested, in an iterative process, to determine which was the most satisfactory for stable cryocondensation pumping. Results from the different tests illustrating the temperature distribution and flow characteristics for each configuration are presented.

  4. Two phase liquid helium flow testing to simulate the operation of a cryocondensation pump in the DIII-D tokamak

    NASA Astrophysics Data System (ADS)

    Laughon, G. J.; Baxi, C. B.; Campbell, G. L.; Mahdavi, M. A.; Makariou, C. C.; Menon, M. M.; Smith, J. P.; Schaffer, M. J.; Schaubel, K. M.

    A liquid helium-cooled cryocondensation pump has been installed in the DIII=D tokamak fusion energy research experiment at General Atomics. The pump is located within the tokamak vacuum chamber beneath the divertor baffle plates and is utilized for plasma density and contamination control. Two-phase helium flows through the pump at 5 to 10 g/s utilizing the beat transfer and constant temperature characteristics of boiling liquid helium. The pump is designed for a pumping speed of 32,0001/s. Extensive testing was performed with a prototypical pump test fixture. Several pump geometries (simple tube, coaxial flow plug, and coaxial slotted insert) were tested, in an iterative process, to determine which was the most satisfactory for stable cryocondensation pumping. Results from the different tests illustrating the temperature distribution and flow characteristics for each configuration are presented.

  5. An experimental study on refrigerant distribution in a two row/four pass parallel flow minichannel heat exchanger

    NASA Astrophysics Data System (ADS)

    Byun, Ho-Won; Kim, Nae-Hyun

    2015-12-01

    R-410A distribution was experimentally studied for a parallel flow evaporator having two row/four pass configuration. The evaporator has inlet, intermediate and row-crossing headers. Tests were conducted for the mass flux from 70 to 130 kg/m2s with the quality at the inlet of 0.2 and exit superheat 5 °C. Significant heat transfer degradation (13-40 %) was realized for the two row/four pass configuration due to flow mal-distribution. Of the three insert hole sizes, 4.0 mm hole yielded the least heat transfer degradation followed by 6.0 and 2.0 mm holes. At the inlet header, more liquid flowed into upstream channels. At the intermediate headers, more liquid was supplied into downstream channels. Similar flow distribution was obtained before and after the row crossing header. Header pressure drops were obtained by subtracting the flat tube pressure drops and other minor pressure drops from measured pressure drops.

  6. Depo-Provera--ethical issues in its testing and distribution.

    PubMed Central

    Potts, M; Paxman, J M

    1984-01-01

    Ethical issues relating to the use of the injectable contraceptive in developed and developing countries alike involve public policy decisions concerning both criteria for testing a new drug and individual choices about using a specific form of contraception approved for national distribution. Drug testing consists of an important but still evolving set of procedures. Depo-Provera is not qualitatively different from any other drug and some unpredictable risks are inevitable, even after extensive animal experiments and clinical trials. In assessing the risks and benefits of Depo-Provera use, epidemiological data from large-scale human use is now beginning to become more important than data from animal experiments and clinical trials. The consumer's best interest is central to any ethically responsible system of drug distribution. Systems of informed choice are needed, even in societies where illiteracy remains common and medical services are weak. In the case of a contraceptive, the risks of non-use leading to unintended pregnancy, which can result in high mortality, are relevant as well as the side-effects of the method. An attempt, therefore, is made here to categorise those issues which are universal and those which are country-specific. PMID:6231379

  7. Nano-iron Tracer Test for Characterizing Preferential Flow Path in Fractured Rock

    NASA Astrophysics Data System (ADS)

    Chia, Y.; Chuang, P. Y.

    2015-12-01

    Deterministic description of the discrete features interpreted from site characterization is desirable for developing a discrete fracture network conceptual model. It is often difficult, however, to delineate preferential flow path through a network of discrete fractures in the field. A preliminary cross-borehole nano-iron tracer test was conducted to characterize the preferential flow path in fractured shale bedrock at a hydrogeological research station. Prior to the test, heat-pulse flowmeter measurements were performed to detect permeable fracture zones at both the injection well and the observation well. While a few fracture zones are found permeable, most are not really permeable. Chemical reduction method was used to synthesize nano zero-valent iron particles with a diameter of 50~150 nm. The conductivity of nano-iron solution is about 3100 μs/cm. The recorded fluid conductivity shows the arrival of nano-iron solution in the observation well 11.5 minutes after it was released from the injection well. The magnetism of zero-valent iron enables it to be absorbed on magnet array designed to locate the depth of incoming tracer. We found nearly all of absorbed iron on the magnet array in the observation well were distributed near the most permeable fracture zone. The test results revealed a preferential flow path through a permeable fracture zone between the injection well and the observation well. The estimated hydraulic conductivity of the connected fracture is 2.2 × 10-3 m/s. This preliminary study indicated that nano-iron tracer test has the potential to characterize preferential flow path in fractured rock.

  8. Distributed training, testing, and decision aids within one solution

    NASA Astrophysics Data System (ADS)

    Strini, Robert A.; Strini, Keith

    2002-07-01

    Military air operations in the European theater require U.S. and NATO participants to send various mission experts to 10 Combined Air Operations Centers (CAOCs). Little or no training occurs prior to their arrival for tours of duty ranging between 90 days to 3 years. When training does occur, there is little assessment of its effectiveness in raising CAOC mission readiness. A comprehensive training management system has been developed that utilizes traditional and web based distance-learning methods for providing instruction and task practice as well as distributed simulation to provide mission rehearsal training opportunities on demand for the C2 warrior. This system incorporates new technologies, such as voice interaction and virtual tutors, and a Learning Management System (LMS) that tracks trainee progress from academic learning through procedural practice and mission training exercises. Supervisors can monitor their subordinate's progress through synchronous or asynchronous methods. Embedded within this system are virtual tutors, which provide automated performance measurement as well as tutoring. The training system offers a true time management savings for current instructors and training providers that today must perform On the Job Training (OJT) duties before, during and after each event. Many units do not have the resources to support OJT and are forced to maintain an overlap of several days to minimally maintain unit readiness. One CAOC Commander affected by this paradigm has advocated supporting a beta version of this system to test its ability to offer training on-demand and track the progress of its personnel and unit readiness. If successful, aircrew simulation devices can be connected through either Distributed Interactive Simulation or High Level Architecture methods to provide a DMT-C2 air operations training environment in Europe. This paper presents an approach to establishing a training, testing and decision aid capability and means to assess

  9. Particle-Size-Distribution of Nevada Test Site Soils

    SciTech Connect

    Spriggs, G; Ray-Maitra, A

    2007-09-17

    The amount of each size particle in a given soil is called the particle-size distribution (PSD), and the way it feels to the touch is called the soil texture. Sand, silt, and clay are the three particle sizes of mineral material found in soils. Sand is the largest sized particle and it feels gritty; silt is medium sized and it feels floury; and clay is the smallest and if feels sticky. Knowing the particle-size distribution of a soil sample helps to understand many soil properties such as how much water, heat, and nutrients the soil will hold, how fast water and heat will move through the soil, and what kind of structure, bulk density and consistence the soil will have. Furthermore, the native particle-size distribution of the soil in the vicinity of ground zero of a nuclear detonation plays a major role in nuclear fallout. For soils that have a high-sand content, the near-range fallout will be relatively high and the far-range fallout will be relatively light. Whereas, for soils that have a high-silt and high-clay content, the near-range fallout will be significantly lower and the far-range fallout will be significantly higher. As part of a program funded by the Defense Threat Reduction Agency (DTRA), the Lawrence Livermore National Laboratory (LLNL) has recently measured the PSDs from the various major areas at the Nevada Test Site where atmospheric detonations and/or nuclear weapon safety tests were performed back in the 50s and 60s. The purpose of this report is to document those results.

  10. Vertical Velocity Distribution in Open-Channel Flow with Rigid Vegetation

    PubMed Central

    Zhu, Changjun; Hao, Wenlong; Chang, Xiangping

    2014-01-01

    In order to experimentally investigate the effects of rigid vegetation on the characteristics of flow, the vegetations were modeled by rigid cylindrical rod. Flow field is measured under the conditions of submerged rigid rod in flume with single layer and double layer vegetations. Experiments were performed for various spacings of the rigid rods. The vegetation models were aligned with the approaching flow in a rectangular channel. Vertical distributions of time-averaged velocity at various streamwise distances were evaluated using an acoustic Doppler velocimeter (ADV). The results indicate that, in submerged conditions, it is difficult to described velocity distribution along the entire depth using unified function. The characteristic of vertical distribution of longitudinal velocity is the presence of inflection. Under the inflection, the line is convex and groove above inflection. The interaction of high and low momentum fluids causes the flow to fold and creates strong vortices within each mixing layer. Understanding the flow phenomena in the area surrounding the tall vegetation, especially in the downstream region, is very important when modeling or studying the riparian environment. ADV measures of rigid vegetation distribution of the flow velocity field can give people a new understanding. PMID:24883352

  11. Study of flow and particle distribution in a bifurcation using dynamic NMR Microscopy

    NASA Astrophysics Data System (ADS)

    Fridjonsson, E. O.; Seymour, J. D.; Codd, S. L.; Cokelet, G. R.

    2007-11-01

    The flow and distribution of Newtonian, polymeric and colloid suspension fluids at low Reynolds numbers in bifurcations has importance in a wide range of disciplines, including microvascular physiology and microfluidic devices. A bifurcation consisting of circular capillaries laser etched in a hard polymer with inlet diameter 2.64 mm, bifurcating to a small diameter outlet of 0.76 mm, and a large outlet of 1.35 mm diameter is examined using four distinct fluids (Water, 0.25 percent (w/w) Xanthan Gum, 8 and 22 percent (v/v) polydisperse oil inside core-shell latex particles) at different flow rates from 5mL/hr to 30mL/hr covering a range of Reynolds numbers based on the entry flow from 0.3 to 8. A Bruker DRX250 NMR system is used with PGSE techniques to obtain dynamic images of the fluids inside the bifurcation. Velocity in all three spatial directions is examined to determine the impact of secondary flows and characterize the transport in the bifurcation. The velocity data provides direct measurement of the volumetric distribution of the flow between the two channels. For the colloidal particle flow the distribution of colloid particles down the capillary is determined by examining the spectrally resolved propagator for the oil inside the core-shell particles in the direction perpendicular to the axial flow. Using dynamic NMR Microscopy the potential for using magnetic resonance for particle counting in a microscale bifurcation is thus demonstrated.

  12. Measuring Temperature in Pipe Flow with Non-Homogeneous Temperature Distribution

    NASA Astrophysics Data System (ADS)

    Klason, P.; Kok, G. J.; Pelevic, N.; Holmsten, M.; Ljungblad, S.; Lau, P.

    2014-04-01

    Accurate temperature measurements in flow lines are critical for many industrial processes. It is normally more a rule than an exception in such applications to obtain water flows with inhomogeneous temperature distributions. In this paper, a number of comparisons were performed between different 100 ohm platinum resistance thermometer (Pt-100) configurations and a new speed-of-sound-based temperature sensor used to measure the average temperature of water flows with inhomogeneous temperature distributions. The aim was to achieve measurement deviations lower than 1 K for the temperature measurement of water flows with inhomogeneous temperature distributions. By using a custom-built flow injector, a water flow with a hot-water layer on top of a cold-water layer was created. The temperature difference between the two layers was up to 32 K. This study shows that the deviations to the temperature reference for the average temperature of four Pt-100s, the multisensor consisting of nine Pt-100s, and the new speed-of-sound sensors are remarkably lower than the deviation for a single Pt-100 under the same conditions. The aim of reaching a deviation lower than 1 K was achieved with the speed-of-sound sensors, the configuration with four Pt-100s, and the multisensor. The promising results from the speed-of sound temperature sensors open the possibility for an integrated flow and temperature sensor. In addition, the immersion depth of a single Pt-100 was also investigated at three different water temperatures.

  13. Application of the mobility power flow approach to structural response from distributed loading

    NASA Technical Reports Server (NTRS)

    Cuschieri, J. M.

    1988-01-01

    The problem of the vibration power flow through coupled substructures when one of the substructures is subjected to a distributed load is addressed. In all the work performed thus far, point force excitation was considered. However, in the case of the excitation of an aircraft fuselage, distributed loading on the whole surface of a panel can be as important as the excitation from directly applied forces at defined locations on the structures. Thus using a mobility power flow approach, expressions are developed for the transmission of vibrational power between two coupled plate substructures in an L configuration, with one of the surfaces of one of the plate substructures being subjected to a distributed load. The types of distributed loads that are considered are a force load with an arbitrary function in space and a distributed load similar to that from acoustic excitation.

  14. Experimental investigation of the enthalpy and mass flow distribution in 16-rod clusters with BWR-PWR geometries and conditions

    NASA Astrophysics Data System (ADS)

    Herkenrath, H.; Hufschmidt, W.; Jung, U.; Weckermann, F.

    Enthalpy and mass flow distribution at the outlet of two test sections with uniform heating in axial and radial direction under steady state conditions was measured by simultaneous sampling of five of six characteristic subchannels in the bundle, using the isokinetic technique and analyzing the outlet quantities by a calorimetric method. Results show low steam quality for the corner subchannel under BWR conditions, due to a thick liquid film on the unheated channel wall. Experimental data confirm the usefullness of the subchannel sampling technique for understanding thermohydraulic phenomena under two-phase flow conditions in multirod bundles. Subchannel resistance coefficients for both types of spacers under one-phase flow conditions were calculated by a substructure method, showing a high local value of the corner subchannel. Total resistance of the spacer was evaluated using local drag coefficients. It agrees well with measured values under adiabatic conditions.

  15. 42 CFR 84.94 - Gas flow test; closed-circuit apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Gas flow test; closed-circuit apparatus. 84.94...-Contained Breathing Apparatus § 84.94 Gas flow test; closed-circuit apparatus. (a) Where oxygen is supplied... rated service time of the apparatus. (b) Where constant flow is used in conjunction with demand...

  16. Oscillating-flow loss test results in rectangular heat exchanger passages

    NASA Technical Reports Server (NTRS)

    Wood, J. Gary

    1991-01-01

    Test results of oscillating flow losses in rectangular heat exchanger passages of various aspect ratios are given. This work was performed in support of the design of a free-piston Stirling engine (FPSE) for a dynamic space power conversion system. Oscillating flow loss testing was performed using an oscillating flow rig, which was based on a variable stroke and variable frequency linear drive motor. Tests were run over a range of oscillating flow parameters encompassing the flow regimes of the proposed engine design. Test results are presented in both tabular and graphical form and are compared against analytical predictions.

  17. Flow channeling and analysis of tracer tests in heterogeneous porous media

    SciTech Connect

    Moreno, Luis; Tsang, Chin-Fu

    2001-11-03

    Flow and solute transport through porous medium with strongly varying hydraulic conductivity are studied by numerical simulations. The heterogeneity of the porous medium is defined by {sigma} and {lambda}{prime}, which are, respectively, the standard deviation of natural log of permeability values and its correlation range {lambda} divided by transport distance L. The development of flow channeling as a function of these two parameters is demonstrated. The results show that for large heterogeneities, the flow is highly channelized and solute is transported through a few fast paths, and the corresponding breakthrough curves show a high peak at very early times, much shorter than the mean residence time. This effect was studied for a converging radial flow, to simulate tracer tests in a fracture zone or contact-thickness aquifer. It is shown that {sigma}{sup 2}{lambda}{prime} is an appropriate parameter to characterize the tracer dispersion and breakthrough curves. These results are used to study tracer breakthrough data from field experiments performed with nonsorbing tracers. A new procedure is proposed to analyze the results. From the moments of the residence-time distribution represented by the breakthrough curves, the heterogeneity of the porous medium, as characterized by {sigma}{sup 2}{lambda}{prime} and the mean residence time t{sub o}, may be determined.

  18. Flow Distribution Around the SSME Main Injector Assembly Using Porosity Formulation

    NASA Technical Reports Server (NTRS)

    Cheng, Gary C.; Chen, Yen-Sen; Wang, Ten-See

    1995-01-01

    Hot gas turbulent flow distribution around the main injector assembly of the Space Shuttle Main Engine (SSME) and Liquid Oxidizer (LOX) flow distribution through the LOX posts have a great effect on the combustion phenomena inside the main combustion chamber. In order to design a CFD model to be an effective engineering analysis tool with good computational turn-around time (especially for 3-D flow problems) and still maintain good accuracy in describing the flow features, the concept of porosity was employed to describe the effects of blockage and drag force due to the presence of the LOX posts in the turbulent flow field around the main injector assembly of the SSME. 2-D numerical studies were conducted to identify the drag coefficients of the flows both through tube banks and around the shielded posts over a wide range of Reynolds numbers. Empirical, analytical expressions of the drag coefficient as a function of local flow Reynolds number were then deduced. The porosity model was applied to the turbulent flow around the main injector assembly of the SSME, and analyses were performed. The 3-D CFD analysis was divided into three parts, LOX dome, hot gas injector assembly, and hydrogen cavity. The numerical results indicate that the mixture ratio at the downstream of injector face was close to stoichiometric around baffle elements.

  19. Flow Distribution Around the SSME Main Injector Assembly Using Porosity Formulation

    NASA Technical Reports Server (NTRS)

    Cheng, Gary C.; Chen, Yen-Sen; Wang, Ten-See

    1995-01-01

    Hot gas turbulent flow distribution around the main injector assembly of the Space Shuttle Main Engine (SSME) and Liquid Oxidizer (LOX) flow distribution through the LOX posts have a great effect on the combustion phenomena inside the main combustion chamber. In order to design a CFD model to be an effective engineering analysis tool with good computational turn- around time (especially for 3-D flow problems) and still maintain good accuracy in describing the flow features, the concept of porosity was employed to describe the effects of blockage and drag force due to the presence of the LOX posts in the turbulent flow field around the main injector assembly of the SSME. 2-D numerical studies were conducted to identify the drag coefficients of the flows both through tube banks and around the shielded posts over a wide range of Reynolds numbers. Empirical, analytical expressions of the drag coefficient as a function of local flow Reynolds number were then deduced. The porosity model was applied to the turbulent flow around the main injector assembly of the SSME, and analyses were performed. The 3-D CFD analysis was divided into three parts, LOX dome, hot gas injector assembly, and hydrogen cavity. The numerical results indicate that the mixture ratio at the downstream of injector face was close to stoichiometric around baffle elements.

  20. Distributed flow sensing for closed-loop speed control of a flexible fish robot.

    PubMed

    Zhang, Feitian; Lagor, Francis D; Yeo, Derrick; Washington, Patrick; Paley, Derek A

    2015-12-01

    Flexibility plays an important role in fish behavior by enabling high maneuverability for predator avoidance and swimming in turbulent flow. This paper presents a novel flexible fish robot equipped with distributed pressure sensors for flow sensing. The body of the robot is molded from soft, hyperelastic material, which provides flexibility. Its Joukowski-foil shape is conducive to modeling the fluid analytically. A quasi-steady potential-flow model is adopted for real-time flow estimation, whereas a discrete-time vortex-shedding flow model is used for higher-fidelity simulation. The dynamics for the flexible fish robot yield a reduced model for one-dimensional swimming. A recursive Bayesian filter assimilates pressure measurements to estimate flow speed, angle of attack, and foil camber. The closed-loop speed-control strategy combines an inverse-mapping feedforward controller based on an average model derived for periodic actuation of angle-of-attack and a proportional-integral feedback controller utilizing the estimated flow information. Simulation and experimental results are presented to show the effectiveness of the estimation and control strategy. The paper provides a systematic approach to distributed flow sensing for closed-loop speed control of a flexible fish robot by regulating the flapping amplitude. PMID:26495855

  1. Renal blood flow distribution during E. coli endotoxin shock in dog.

    PubMed

    Kirkebø, A; Tyssebotn, I

    1980-04-01

    The effect of endotoxin on renal blood flow distribution was studied in anesthetized dogs. Renal blood flow was measured as hydrogen clearance by platinum electrodes placed in outer and in inner halves of cortex and by electromagnetic flowmeter. Intravenous injection of E. coli endotoxin, 3-5 mg/kg b. wt., promptly reduced arterial blood pressure (AP) and renal blood flow. After a transient increase for 45 min AP and renal blood flow declined to about 50% of the control 2 1/2-3 h after injection. The reduction in outer cortical blood flow (OCF) was not significantly different from the reduction in inner cortical blood flow (ICF). The hematocrit (Hct) increased from 40.1 +/- 3.8% to 54.6 +/- 8%, but mean renal vascular resistance did not change. Total plasma protein concentration was not significantly elevated. A marked local flow variability was observed in some periods during the phase of shock with declining AP and total renal blood flow at high Hct. Thus renal blood flow showed phasic changes, but the OCF/ICF ratio was not changed during endotoxin shock. Local blood flow instability was observed periodically at high Hct. PMID:6998257

  2. Distributed control of reactive power flow in a radial distribution circuit with high photovoltaic penetration

    SciTech Connect

    Chertkov, Michael; Turitsyn, Konstantin; Backhaus, Scott; Sule, Petr

    2009-01-01

    We show how distributed control of reactive power can serve to regulate voltage and minimize resistive losses in a distribution circuit that includes a significant level of photovoltaic (PV) generation. To demonstrate the technique, we consider a radial distribution circuit with a single branch consisting of sequentially-arranged residential-scale loads that consume both real and reactive power. In parallel, some loads also have PV generation capability. We postulate that the inverters associated with each PV system are also capable of limited reactive power generation or consumption, and we seek to find the optimal dispatch of each inverter's reactive power to both maintain the voltage within an acceptable range and minimize the resistive losses over the entire circuit. We assume the complex impedance of the distribution circuit links and the instantaneous load and PV generation at each load are known. We compare the results of the optimal dispatch with a suboptimal local scheme that does not require any communication. On our model distribution circuit, we illustrate the feasibility of high levels of PV penetration and a significant (20% or higher) reduction in losses.

  3. Changes in mobile phase ion distribution when combining pressurized flow and electric field.

    PubMed

    Eriksson, Björn O; Dahl, Magnus; Andersson, Magnus B O; Blomberg, Lars G

    2004-10-01

    The distribution of ions in a capillary with both pressurized flow and an electric field has been studied. We have earlier reported that the overall concentration of ions increase in a capillary with high electric field and a pressurized flow. Now we describe how the ions are distributed in the capillary both along the capillary length and in the radial direction as a result of the parabolic flow profile. We have combined current measurements with finite element techniques in order to get better understanding of the system. We have found that the concentration of the ions that because of the electric mobility moves towards the flow primarily increases at the beginning of the electric field and close to the capillary wall. In view of the results we have proposed an alterative explanation of earlier published results concerning voltage-induced variation in capacity factors. PMID:15472979

  4. Small-scale Rainfall Challenges Tested with Semi-distributed and Distributed Hydrological Models

    NASA Astrophysics Data System (ADS)

    Ichiba, Abdellah; Tchiguirinskaia, Ioulia; Gires, Auguste; Schertzer, Daniel; Bompard, Philippe

    2016-04-01

    Nowadays, there is a growing interest on small-scale rainfall information, provided by weather radars, to be used in urban water management and decision-making. Indeed, it helps to better understand the essential interactions between natural and man-made urban environments, both being complex systems. However the integration of this information in hydrological models remains a big challenge. In fact, urban water managers often rely on lumped or semi-distributed models with much coarser data resolution. The scope of this work is to investigate the sensitivity of two hydrological models to small-scale rainfall, and their potential improvements to integrate wholly the small-scale information. The case study selected to perform this study is a small urban catchment (245 ha), located at Val-de-Marne county (southeast of Paris, France). Investigations were conducted using either CANOE model, a semi-distributed conceptual model that is widely used in France for urban modeling, or a fully distributed and physically based model, Multi-Hydro, developed at Ecole des Ponts ParisTech (www hmco-dev.enpc.fr/Tools-Training/Tools/Multi-Hydro.php). Initially, in CANOE model the catchment was divided into 9 sub-catchments with size ranging from 1ha to 76ha. A refinement process was conduced in the framework of this investigation in order to improve the model resolution by considering higher number of smaller sub-catchments. The new configuration consists of 44 sub-catchments with size ranging from 1ha-14ha. The Multi-Hydro modeling approach consists on rasterizing the catchment information to a regular spatial grid of a resolution chosen by the user. Each pixel is then affected by specific information, e.g., a unique land type per pixel, for which hydrological and physical properties are set. First of all, both models were validated with respect to real flow measurements using three types of rainfall data: (1) point measurement data coming form the Sucy-en-Brie rain gauge; (2) Meteo

  5. Quantization of Prior Probabilities for Collaborative Distributed Hypothesis Testing

    NASA Astrophysics Data System (ADS)

    Rhim, Joong Bum; Varshney, Lav R.; Goyal, Vivek K.

    2012-09-01

    This paper studies the quantization of prior probabilities, drawn from an ensemble, for distributed detection and data fusion. Design and performance equivalences between a team of N agents tied by a fixed fusion rule and a more powerful single agent are obtained. Effects of identical quantization and diverse quantization are compared. Consideration of perceived common risk enables agents using diverse quantizers to collaborate in hypothesis testing, and it is proven that the minimum mean Bayes risk error is achieved by diverse quantization. The comparison shows that optimal diverse quantization with K cells per quantizer performs as well as optimal identical quantization with N(K-1)+1 cells per quantizer. Similar results are obtained for maximum Bayes risk error as the distortion criterion.

  6. EFFECTS OF TEST TEMPERATURE ON FLOW OF METALLIC GLASSES

    SciTech Connect

    A.S. NOURI; Y. LIU; P. WESSELING; J. LEWANDOWSKI

    2006-04-12

    Micro-hardness experiments were conducted over a range of temperatures using a Nikon QM micro-hardness machine on a number of metallic glass (e.g. Zr-, Fe-, Al-) systems. Although high micro-hardness was exhibited at room temperature, significant hardness reductions were exhibited near the glass transition temperature, T{sub g}. The effects of changes in test temperature on the micro-hardness will be reported. The effects of exposure time on the hardness evolution at a given temperature will also be summarized to illustrate some of the differences in behavior of the systems shown. The extreme softening near T{sub g}, characteristic of bulk metallic glass systems, enables the exploration of novel deformation processing. In order to develop deformation processing windows, the evaluation of bulk metallic glass mechanical properties under quasi-static conditions and the determination of flow properties at different temperatures and strain rates are reported. The use of such information to create layered/composite bulk metallic glasses will be summarized.

  7. Flow distribution analysis on the cooling tube network of ITER thermal shield

    NASA Astrophysics Data System (ADS)

    Nam, Kwanwoo; Chung, Wooho; Noh, Chang Hyun; Kang, Dong Kwon; Kang, Kyoung-O.; Ahn, Hee Jae; Lee, Hyeon Gon

    2014-01-01

    Thermal shield (TS) is to be installed between the vacuum vessel or the cryostat and the magnets in ITER tokamak to reduce the thermal radiation load to the magnets operating at 4.2K. The TS is cooled by pressurized helium gas at the inlet temperature of 80K. The cooling tube is welded on the TS panel surface and the composed flow network of the TS cooling tubes is complex. The flow rate in each panel should be matched to the thermal design value for effective radiation shielding. This paper presents one dimensional analysis on the flow distribution of cooling tube network for the ITER TS. The hydraulic cooling tube network is modeled by an electrical analogy. Only the cooling tube on the TS surface and its connecting pipe from the manifold are considered in the analysis model. Considering the frictional factor and the local loss in the cooling tube, the hydraulic resistance is expressed as a linear function with respect to mass flow rate. Sub-circuits in the TS are analyzed separately because each circuit is controlled by its own control valve independently. It is found that flow rates in some panels are insufficient compared with the design values. In order to improve the flow distribution, two kinds of design modifications are proposed. The first one is to connect the tubes of the adjacent panels. This will increase the resistance of the tube on the panel where the flow rate is excessive. The other design suggestion is that an orifice is installed at the exit of tube routing where the flow rate is to be reduced. The analysis for the design suggestions shows that the flow mal-distribution is improved significantly.

  8. Flow distribution analysis on the cooling tube network of ITER thermal shield

    SciTech Connect

    Nam, Kwanwoo; Chung, Wooho; Noh, Chang Hyun; Kang, Dong Kwon; Kang, Kyoung-O; Ahn, Hee Jae; Lee, Hyeon Gon

    2014-01-29

    Thermal shield (TS) is to be installed between the vacuum vessel or the cryostat and the magnets in ITER tokamak to reduce the thermal radiation load to the magnets operating at 4.2K. The TS is cooled by pressurized helium gas at the inlet temperature of 80K. The cooling tube is welded on the TS panel surface and the composed flow network of the TS cooling tubes is complex. The flow rate in each panel should be matched to the thermal design value for effective radiation shielding. This paper presents one dimensional analysis on the flow distribution of cooling tube network for the ITER TS. The hydraulic cooling tube network is modeled by an electrical analogy. Only the cooling tube on the TS surface and its connecting pipe from the manifold are considered in the analysis model. Considering the frictional factor and the local loss in the cooling tube, the hydraulic resistance is expressed as a linear function with respect to mass flow rate. Sub-circuits in the TS are analyzed separately because each circuit is controlled by its own control valve independently. It is found that flow rates in some panels are insufficient compared with the design values. In order to improve the flow distribution, two kinds of design modifications are proposed. The first one is to connect the tubes of the adjacent panels. This will increase the resistance of the tube on the panel where the flow rate is excessive. The other design suggestion is that an orifice is installed at the exit of tube routing where the flow rate is to be reduced. The analysis for the design suggestions shows that the flow mal-distribution is improved significantly.

  9. Revealing β-relaxation mechanism based on energy distribution of flow units in metallic glass.

    PubMed

    Lu, Z; Shang, B S; Sun, Y T; Zhu, Z G; Guan, P F; Wang, W H; Bai, H Y

    2016-04-14

    The β-relaxation, which is the source of the dynamics in glass state and has practical significance to relaxation and mechanical properties of glasses, has been an open question for decades. Here, we propose a flow unit perspective to explain the structural origin and evolution of β-relaxation based on experimentally obtained energy distribution of flow units using stress relaxation method under isothermal and linear heating modes. Through the molecular dynamics simulations, we creatively design various artificial metallic glass systems and build a direct relation between β-relaxation behavior and features of flow units. Our results demonstrate that the β-relaxation in metallic glasses originates from flow units and is modulated by the energy distribution of flow units, and the density and distribution of flow units can effectively regulate the β-relaxation behavior. The results provide a better understanding of the structural origin of β-relaxation and also afford a method for designing metallic glasses with obvious β-relaxation and better mechanical properties. PMID:27083732

  10. Revealing β-relaxation mechanism based on energy distribution of flow units in metallic glass

    NASA Astrophysics Data System (ADS)

    Lu, Z.; Shang, B. S.; Sun, Y. T.; Zhu, Z. G.; Guan, P. F.; Wang, W. H.; Bai, H. Y.

    2016-04-01

    The β-relaxation, which is the source of the dynamics in glass state and has practical significance to relaxation and mechanical properties of glasses, has been an open question for decades. Here, we propose a flow unit perspective to explain the structural origin and evolution of β-relaxation based on experimentally obtained energy distribution of flow units using stress relaxation method under isothermal and linear heating modes. Through the molecular dynamics simulations, we creatively design various artificial metallic glass systems and build a direct relation between β-relaxation behavior and features of flow units. Our results demonstrate that the β-relaxation in metallic glasses originates from flow units and is modulated by the energy distribution of flow units, and the density and distribution of flow units can effectively regulate the β-relaxation behavior. The results provide a better understanding of the structural origin of β-relaxation and also afford a method for designing metallic glasses with obvious β-relaxation and better mechanical properties.

  11. Effect of furosemide on pulmonary blood flow distribution in resting and exercising horses

    NASA Technical Reports Server (NTRS)

    Erickson, H. H.; Bernard, S. L.; Glenny, R. W.; Fedde, M. R.; Polissar, N. L.; Basaraba, R. J.; Walther, S. M.; Gaughan, E. M.; McMurphy, R.; Hlastala, M. P.

    1999-01-01

    We determined the spatial distribution of pulmonary blood flow (PBF) with 15-micron fluorescent-labeled microspheres during rest and exercise in five Thoroughbred horses before and 4 h after furosemide administration (0.5 mg/kg iv). The primary finding of this study was that PBF redistribution occurred from rest to exercise, both with and without furosemide. However, there was less blood flow to the dorsal portion of the lung during exercise postfurosemide compared with prefurosemide. Furosemide did alter the resting perfusion distribution by increasing the flow to the ventral regions of the lung; however, that increase in flow was abated with exercise. Other findings included 1) unchanged gas exchange and cardiac output during rest and exercise after vs. before furosemide, 2) a decrease in pulmonary arterial pressure after furosemide, 3) an increase in the slope of the relationship of PBF vs. vertical height up the lung during exercise, both with and without furosemide, and 4) a decrease in blood flow to the dorsal region of the lung at rest after furosemide. Pulmonary perfusion variability within the lung may be a function of the anatomy of the pulmonary vessels that results in a predominantly fixed spatial pattern of flow distribution.

  12. Availability and Distribution of Base Flow in Lower Honokohau Stream, Island of Maui

    USGS Publications Warehouse

    Fontaine, Richard A.

    2003-01-01

    Honokohau Stream is one of the few perennial streams in the Lahaina District of West Maui. Current Honokohau water-use practices often lead to conflicts among water users, which are most evident during periods of base flow. To better manage the resource, data are needed that describe the availability and distribution of base flow in lower Honokohau Stream and how base flow is affected by streamflow diversion and return-flow practices. Flow-duration discharges for percentiles ranging from 50 to 95 percent were estimated at 13 locations on lower Honokohau Stream using data from a variety of sources. These sources included (1) available U.S. Geological Survey discharge data, (2) published summaries of Maui Land & Pineapple Company, Inc. diversion and water development-tunnel data, (3) seepage run and low-flow partial-record discharge measurements made for this study, and (4) current (2003) water diversion and return-flow practices. These flow-duration estimates provide a detailed characterization of the distribution and availability of base flow in lower Honokohau Stream. Estimates of base-flow statistics indicate the significant effect of Honokohau Ditch diversions on flow in the stream. Eighty-six percent of the total flow upstream from the ditch is diverted from the stream. Immediately downstream from the diversion dam there is no flow in the stream 91.2 percent of the time, except for minor leakage through the dam. Flow releases at the Taro Gate, from Honokohau Ditch back into the stream, are inconsistent and were found to be less than the target release of 1.55 cubic feet per second on 9 of the 10 days on which measurements were made. Previous estimates of base-flow availability downstream from the Taro Gate release range from 2.32 to 4.6 cubic feet per second (1.5 to 3.0 million gallons per day). At the two principal sites where water is currently being diverted for agricultural use in the valley (MacDonald's and Chun's Dams), base flows of 2.32 cubic feet per

  13. The pressure distribution on the surface of an ellipsoid in inviscid flow

    NASA Astrophysics Data System (ADS)

    Band, E. G. U.; Payne, P. R.

    1980-02-01

    The classic equations for inviscid flow about an ellipsoid are employed to compute the corresponding static pressure distribution which can then be applied to a number of practical problems. The tension in the skin of a dirigible, the gross pressure distribution around a man in an open ejection seat, the aerodynamic lift on an air cushion vehicle, automobile or high speed boat, the 'squatting' of a ship, are all examples of practical applications. A remarkable result from the theory is that the lowest pressure, that around the equator normal to the flow, is always constant around the equator, no matter how much disparity there is between the semi-axes b and c.

  14. SR-71 LASRE during in-flight cold flow test

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This shot, from above and behind the SR-71 in flight, runs 11 seconds and shows the Aerospike engine and its fuel system being charged with gaseous helium and liquid nitrogen during one of two tests. The tests are to check for leaks and check the flow characteristics of cryogenic fuels to be used in the engine. The NASA/Lockheed Martin Linear Aerospike SR-71 Experiment (LASRE) concluded its flight operations phase at the NASA Dryden Flight Research Center, Edwards, California, in November 1998. The goal of this experiment was to provide in-flight data to help Lockheed Martin, Bethesda, Maryland, validate the computational predictive tools it was using to determine the aerodynamic performance of a future potential reusable launch vehicle. Information from the LASRE experiment will help Lockheed Martin maximize its design for a future potential reusable launch vehicle. It gave Lockheed an understanding of the performance of the lifting body and linear aerospike engine combination even before the X-33 Advanced Technology Demonstrator flies. LASRE was a small, half-span model of a lifting body with eight thrust cells of an aerospike engine. The experiment, mounted on the back of an SR-71 aircraft, operates like a kind of 'flying wind tunnel.' The experiment focused on determining how the engine plume of a reusable launch vehicle engine plume would affect the aerodynamics of its lifting body shape at specific altitudes and speeds reaching approximately 750 miles per hour. The interaction of the aerodynamic flow with the engine plume could create drag; design refinements look to minimize that interaction. During the flight research program, the aircraft completed seven research flights. Two initial flights were used to determine the aerodynamic characteristics of the LASRE apparatus on the back of the aircraft. The first of those two flights occurred October 31, 1997. The SR-71 took off at 8:31 a.m. PST. The aircraft flew for one hour and fifty minutes, reaching a

  15. Rapid, high-order accurate calculation of flows due to free source or vortex distributions

    NASA Technical Reports Server (NTRS)

    Halsey, D.

    1981-01-01

    Fast Fourier transform (FFT) techniques are applied to the problem of finding the flow due to source or vortex distributions in the field outside an airfoil or other two-dimensional body. Either the complex potential or the complex velocity may be obtained to a high order of accuracy, with computational effort similar to that required by second-order fast Poisson solvers. These techniques are applicable to general flow problems with compressibility and rotation. An example is given of their use for inviscid compressible flow.

  16. Testing calibration routines for LISFLOOD, a distributed hydrological model

    NASA Astrophysics Data System (ADS)

    Pannemans, B.

    2009-04-01

    Traditionally hydrological models are considered as difficult to calibrate: their highly non-linearity results in rugged and rough response surfaces were calibration algorithms easily get stuck in local minima. For the calibration of distributed hydrological models two extra factors play an important role: on the one hand they are often costly on computation, thus restricting the feasible number of model runs; on the other hand their distributed nature smooths the response surface, thus facilitating the search for a global minimum. Lisflood is a distributed hydrological model currently used for the European Flood Alert System - EFAS (Van der Knijff et al, 2008). Its upcoming recalibration over more then 200 catchments, each with an average runtime of 2-3 minutes, proved a perfect occasion to put several existing calibration algorithms to the test. The tested routines are Downhill Simplex (DHS, Nelder and Mead, 1965), SCEUA (Duan et Al. 1993), SCEM (Vrugt et al., 2003) and AMALGAM (Vrugt et al., 2008), and they were evaluated on their capability to efficiently converge onto the global minimum and on the spread in the found solutions in repeated runs. The routines were let loose on a simple hyperbolic function, on a Lisflood catchment using model output as observation, and on two Lisflood catchments using real observations (one on the river Inn in the Alps, the other along the downstream stretch of the Elbe). On the mathematical problem and on the catchment with synthetic observations DHS proved to be the fastest and the most efficient in finding a solution. SCEUA and AMALGAM are a slower, but while SCEUA keeps converging on the exact solution, AMALGAM slows down after about 600 runs. For the Lisflood models with real-time observations AMALGAM (hybrid algorithm that combines several other algorithms, we used CMA, PSO and GA) came as fastest out of the tests, and giving comparable results in consecutive runs. However, some more work is needed to tweak the stopping

  17. Predicting spatial distribution of postfire debris flows and potential consequences for native trout in headwater streams

    USGS Publications Warehouse

    Sedell, Edwin R; Gresswell, Bob; McMahon, Thomas E.

    2015-01-01

    Habitat fragmentation and degradation and invasion of nonnative species have restricted the distribution of native trout. Many trout populations are limited to headwater streams where negative effects of predicted climate change, including reduced stream flow and increased risk of catastrophic fires, may further jeopardize their persistence. Headwater streams in steep terrain are especially susceptible to disturbance associated with postfire debris flows, which have led to local extirpation of trout populations in some systems. We conducted a reach-scale spatial analysis of debris-flow risk among 11 high-elevation watersheds of the Colorado Rocky Mountains occupied by isolated populations of Colorado River Cutthroat Trout (Oncorhynchus clarkii pleuriticus). Stream reaches at high risk of disturbance by postfire debris flow were identified with the aid of a qualitative model based on 4 primary initiating and transport factors (hillslope gradient, flow accumulation pathways, channel gradient, and valley confinement). This model was coupled with a spatially continuous survey of trout distributions in these stream networks to assess the predicted extent of trout population disturbances related to debris flows. In the study systems, debris-flow potential was highest in the lower and middle reaches of most watersheds. Colorado River Cutthroat Trout occurred in areas of high postfire debris-flow risk, but they were never restricted to those areas. Postfire debris flows could extirpate trout from local reaches in these watersheds, but trout populations occupy refugia that should allow recolonization of interconnected, downstream reaches. Specific results of our study may not be universally applicable, but our risk assessment approach can be applied to assess postfire debris-flow risk for stream reaches in other watersheds.

  18. Sensitivity of Flow Uncertainty to Radar Rainfall Uncertainty in the Context of Operational Distributed Hydrologic Modeling

    NASA Astrophysics Data System (ADS)

    Carpenter, T. M.; Georgakakos, K. P.; Georgakakos, K. P.

    2001-12-01

    The current study focuses on the sensitivity of distributed model flow forecast uncertainty to the uncertainty in the radar rainfall input. Various studies estimate a 30 to 100% uncertainty in radar rainfall estimates from the operational NEXRAD radars. This study addresses the following questions: How does this uncertainty in rainfall input impact the flow simulations produced by a hydrologic model? How does this effect compare to the uncertainty in flow forecasts resulting from initial condition and model parametric uncertainty? The hydrologic model used, HRCDHM, is a catchment-based, distributed hydrologic model and accepts hourly precipitation input from the operational WSR-88D weather radar. A GIS is used to process digital terrain data, delineate sub-catchments of a given large watershed, and supply sub-catchment characteristics (subbasin area, stream length, stream slope and channel-network topology) to the hydrologic model components. HRCDHM uses an adaptation of the U.S. NWS operational Sacramento soil moisture accounting model to produce runoff for each sub-catchment within the larger study watershed. Kinematic or Muskingum-Cunge channel routing is implemented to combine and route sub-catchment flows through the channel network. Available spatial soils information is used to vary hydrologic model parameters from sub-catchment to sub-catchment. HRCDHM was applied to the 2,500 km2 Illinois River watershed in Arkansas and Oklahoma with outlet at Tahlequah, Oklahoma. The watershed is under the coverage of the operational WSR-88D radar at Tulsa, Oklahoma. For distributed modeling, the watershed area has been subdivided into sub-catchments with an average area of 80km2. Flow simulations are validated at various gauged locations within the watershed. A Monte Carlo framework was used to assess the sensitivity of the simulated flows to uncertainty in radar input for different radar error distributions (uniform or exponential), and to make comparisons to the flow

  19. Some recent progress in transonic flow computation. [flow distribution, numerical optimization, and airfoil design

    NASA Technical Reports Server (NTRS)

    Ballhaus, W. F.

    1976-01-01

    Although the development of a finite difference relaxation procedure to solve the steady form of equations of motion gave birth to the study of computational transonic aerodynamics and considerable progress has been made using the small disturbance theory, no general analytical solution method yet exists for transonic flows that include three dimensional unsteady, and viscous effects. Two techniques are described which are useful in computational transonic aerodynamics applications. The finite volume method simplifies the application of boundary conditions without introducing the constriction associated with small disturbance theory. Governing equations are solved in a Cartesian coordinate system using a body-oriented and shock-oriented mesh network. Only the volume and surface normal directions of the volume elements must be known. The other method, configuration design by numerical optimization, can be used by aircraft designers to develop configurations that satisfy specific geometric performance constraints. Two examples of airfoil design by numerical optimization are presented.

  20. Computation of stress distribution in a mixed flow pump based on fluid-structure interaction analysis

    NASA Astrophysics Data System (ADS)

    Hu, F. F.; Chen, T.; Wu, D. Z.; Wang, L. Q.

    2013-12-01

    The internal flow evolution of the pump was induced with impeller movement. In various conditions, the peak load on centrifugal blade under the change of rotational speed or flow rate was also changed. It would cause an error when inertia load with a safety coefficient (that was difficult to ascertain) was applied in structure design. In order to accurately analyze the impeller stress under various conditions and improve the reliability of pump, based on a mixed flow pump model, the stress distribution characteristic was analyzed under different flow rates and rotational speeds. Based on a three-dimensional calculation model including impeller, guide blade, inlet and outlet, the three-dimension incompressible turbulence flow in the centrifugal pump was simulated by using the standard k-epsilon turbulence model. Based on the sequentially coupled simulation approach, a three-dimensional finite element model of impeller was established, and the fluid-structure interaction method of the blade load transfer was discussed. The blades pressure from flow simulation, together with inertia force acting on the blade, was used as the blade loading on solid surface. The Finite Element Method (FEM) was used to calculate the stress distribution of the blade respectively under inertia load, or fluid load, or combined load. The results showed that the blade stress changed with flow rate and rotational speed. In all cases, the maximum stress on the blade appeared on the pressure side near the hub, and the maximum static stress increased with the decreasing of the flow rate and the increasing of rotational speed. There was a big difference on the static stress when inertia load, fluid load and combined loads was applied respectively. In order to more accurately calculate the stress distribution, the structure analysis should be conducted due to combined loads. The results could provide basis for the stress analysis and structure optimization of pump.

  1. Analytical arrival and persistence time distributions for flow thresholds in seasonally dry climates

    NASA Astrophysics Data System (ADS)

    Dralle, D.; Thompson, S. E.

    2014-12-01

    Seasonally dry ecosystems, which include Mediterranean, tropical monsoonal and tropical savannah climates, cover approximately 30% of the planet's land area and are globally significant biodiversity hotspots. Due to a highly variable climate, the streamflow available for ecosystems and ecosystems services in these regions is typified by large inter-annual variability. Methods to quantify this variability could shed light on stream ecosystem stress, particularly new stresses imposed by human activity or climate change. This study develops a probabilistic framework to examine controls on dry season flow characteristics in seasonally dry climates. Assuming a typical recession pattern, which is conditioned on an initial value that is sampled from the wet season flows [1,2], analytical PDFs for the arrival time of a given dry season flow threshold can be obtained. Below-flow-threshold persistence time distributions are computed as the difference between an (assumed) normally distributed dry season length and the mean flow threshold arrival time. A number of hypotheses are proposed to explain unexpected sources of variability in the empirical arrival time distributions. The ecologic implications of extended low flow persistence, such as the hydrologic fragmentation of lower order watersheds, are discussed. [1] Müller, M. F., D. N. Dralle, and S. E. Thompson (2014), Analytical model for flow duration curves in seasonally dry climates, Water Resour. Res., 50, doi:10.1002/2014WR015301 [2] Botter, G., A. Porporato, I. Rodriguez-Iturbe, and A. Rinaldo (2007), Basin-scale soil moisture dynamics and the probabilistic characterization of carrier hydrologic flows: Slow, leaching-prone components of the hydrologic response, Water Resour. Res., 43, W02417, doi:10.1029/2006WR005043

  2. Testing low mass flow train in the DOE Coal Fired Flow Facility. Quarterly technical progress report, July-September 1983

    SciTech Connect

    Not Available

    1984-06-01

    UTSI reports on testing of the Low Mass Flow Train in the DOE Coal Fired Flow Facility. During this period eight tests were conducted, which complete the seed/slag interaction test series. Preliminary results of these tests are reported. Additional nitrogen oxide (NO/sub x/) measurements are included, as are SO/sub 2/ removal results. An analysis of deposit accumulation on the tubes in the materials test module is reported. Data obtained from high velocity thermocouple (HVT) probes in the radiant furnace are included for the first time and show essentially a flat temperature profile in the furnace. Heat transfer calculations for the flow train are correlated with experimental measurements, including those obtained from both UTSI and MSU line reversal systems.

  3. Neutron Tomography Using Mobile Neutron Generators for Assessment of Void Distributions in Thermal Hydraulic Test Loops

    NASA Astrophysics Data System (ADS)

    Andersson, P.; Bjelkenstedt, T.; Sundén, E. Andersson; Sjöstrand, H.; Jacobsson-Svärd, S.

    Detailed knowledge of the lateral distribution of steam (void) and water in a nuclear fuel assembly is of great value for nuclear reactor operators and fuel manufacturers, with consequences for both reactor safety and economy of operation. Therefore, nuclear relevant two-phase flows are being studied at dedicated thermal-hydraulic test loop, using two-phase flow systems ranging from simplified geometries such as heated circular pipes to full scale mock-ups of nuclear fuel assemblies. Neutron tomography (NT) has been suggested for assessment of the lateral distribution of steam and water in such test loops, motivated by a good ability of neutrons to penetrate the metallic structures of metal pipes and nuclear fuel rod mock-ups, as compared to e.g. conventional X-rays, while the liquid water simultaneously gives comparatively good contrast. However, these stationary test loops require the measurement setup to be mobile, which is often not the case for NT setups. Here, it is acknowledged that fast neutrons of 14 MeV from mobile neutron generators constitute a viable option for a mobile NT system. We present details of the development of neutron tomography for this purpose at the division of Applied Nuclear Physics at Uppsala University. Our concept contains a portable neutron generator, exploiting the fusion reaction of deuterium and tritium, and a detector with plastic scintillator elements designed to achieveadequate spatial and energy resolution, all mounted in a light-weight frame without collimators or bulky moderation to allow for a mobile instrument that can be moved about the stationary thermal hydraulic test sections. The detector system stores event-to-event pulse-height information to allow for discrimination based on the energy deposition in the scintillator elements.

  4. Bypass thresholds for gravity flows: implications for sand distribution in turbidite systems

    NASA Astrophysics Data System (ADS)

    Dorrell, R. M.; Amy, L.

    2015-12-01

    The stratigraphic architecture of turbidite and other systems dominated by gravity flows is underpinned by the ability to transport sediment as suspended load. The ability to transport sediment is crucial to concepts of flow efficiency and equilibrium profile. Predominately bypass-erosional flows transport their sediment load downslope to the basin; forming sand-starved slope channels and canyons. In contrast, flows that cannot suspend their sediment are depositional on inbound slopes leading to constructional slope systems with sand-filled slope conduits and potentially sand starved basins. An experimentally validated mathematical model for polydisperse turbulent suspension is used to estimate the critical shear velocity (u*c) for the threshold between depositional and erosional regimes in gravity driven flows. The model shows that the criterion is a function of flow concentration and grain-size distribution increasing as stratification increases within flows: arising from either higher particle concentrations or maximum sizes (increased mean, standard deviation and decreased skew). Predicted values of u*c are as much as two orders of magnitude greater than those derived using standard monodisperse sediment transport models (e.g., Rouse criterion). The results presented better constrain the potential for total sediment bypass on slopes in turbidite systems. Representative values of velocity and density from monitored natural sandy turbidity currents show total sediment bypass or erosion may be typical in the head and body of supercritical flows on average canyon slopes.

  5. Distributed forcing of the flow past a blunt-based axisymmetric bluff body

    NASA Astrophysics Data System (ADS)

    Jardin, Thierry; Bury, Yannick; DAEP Team

    2012-11-01

    The topology of bluff body wakes may be highly sensitive to forcing at frequencies close to intrinsic flow instabilities. In a similar way, a steady but spatially varying forcing at wavelengths close to specific flow instabilities can lead to analogous outcomes. Such forcing is commonly referred to as distributed forcing. However, although distributed forcing has proven to be a relevant control strategy for three-dimensional flows past nominally two-dimensional geometries (e.g. extruded circular cylinder at Re > 180), its impact on the flow past nominally three-dimensional geometries is still unknown. Here we assess the receptivity of the flow past a blunt-based axisymmetric bluff body to an azimuthally distributed forcing applied at the periphery of the bluff-body base. We show that the impact of RSPa, RSPb and RSPc instabilities on the drag fluctuations experienced by the bluff body can be suppressed, depending on the forcing wavelengths. The authors acknowledge the French Ministry of Defence and DGA for funding this work.

  6. On the prediction of the phase distribution of bubbly flow in a horizontal pipe.

    PubMed

    Yeoh, G H; Cheung, Sherman C P; Tu, J Y

    2012-01-01

    Horizontal bubbly flow is widely encountered in various industrial systems because of its ability to provide large interfacial areas for heat and mass transfer. Nonetheless, this particular flow orientation has received less attention when compared to vertical bubbly flow. Owing to the strong influence due to buoyancy, the migration of dispersed bubbles towards the top wall of the horizontal pipe generally causes a highly asymmetrical internal phase distributions, which are not experienced in vertical bubbly flow. In this study, the internal phase distribution of air-water bubbly flow in a long horizontal pipe with an inner diameter of 50.3 mm has been predicted using the population balance model based on direct quadrature method of moments (DQMOM) and multiple-size group (MUSIG) model. The predicted local radial distributions of gas void fraction, liquid velocity and interfacial area concentration have been validated against the experimental data of Kocamustafaogullari and Huang (1994). In general, satisfactory agreements between predicted and measured results were achieved. The numerical results indicated that the gas void fraction and interfacial area concentration have a unique internal structure with a prevailing maximum peak near the top wall of the pipe due to buoyancy effect. PMID:24415823

  7. Two-phase distribution in the vertical flow line of a domestic wet central heating system

    NASA Astrophysics Data System (ADS)

    Fsadni, A.-M.; Ge, Y. T.

    2013-04-01

    The theoretical and experimental aspects of bubble distribution in bubbly two-phase flow are reviewed in the context of the micro bubbles present in a domestic gas fired wet central heating system. The latter systems are mostly operated through the circulation of heated standard tap water through a closed loop circuit which often results in water supersaturated with dissolved air. This leads to micro bubble nucleation at the primary heat exchanger wall, followed by detachment along the flow. Consequently, a bubbly two-phase flow characterises the flow line of such systems. The two-phase distribution across the vertical and horizontal pipes was measured through a consideration of the volumetric void fraction, quantified through photographic techniques. The bubble distribution in the vertical pipe in down flow conditions was measured to be quasi homogenous across the pipe section with a negligible reduction in the void fraction at close proximity to the pipe wall. Such a reduction was more evident at lower bulk fluid velocities.

  8. Flow distribution in unglazed transpired plate solar air heaters of large area

    SciTech Connect

    Gunnewiek, L.H.; Brundrett, E.; Hollands, K.G.T.

    1996-10-01

    Unglazed transpired plate solar air heaters have proven to be effective in heating outside air on a once-through basis for ventilation and drying applications. Outside air is sucked through unglazed plates having uniformly distributed perforations. The air is drawn into a plenum behind the plate and then supplied to the application by fans. Large collectors have been built that cover the sides of sizable buildings, and the problem of designing the system so that the air is sucked uniformly everywhere (or nearly so) has proven to be a challenging one. This article describes an analytical tool that has been developed to predict the flow distribution over the collector. It is based on modelling the flow-field in the plenum by means of a commercial CFD (computational fluid mechanics) code, incorporating a special set of boundary conditions to model the plate and the ambient air. The article presents the 2D version of the code, and applies it to the problem of predicting the flow distribution in still air (no wind) conditions, a situation well treated by a 2D code. Results are presented for a wide range of conditions, and design implications are discussed. An interesting finding of the study is that the heat transfer at the back of the plate can play an important role, and because of this heat transfer, the efficiency of a collector in nonuniform flow can actually be greater than that of the same collector in uniform flow. 15 refs., 7 figs.

  9. On the prediction of the phase distribution of bubbly flow in a horizontal pipe

    PubMed Central

    Yeoh, G.H.; Cheung, Sherman C.P.; Tu, J.Y.

    2012-01-01

    Horizontal bubbly flow is widely encountered in various industrial systems because of its ability to provide large interfacial areas for heat and mass transfer. Nonetheless, this particular flow orientation has received less attention when compared to vertical bubbly flow. Owing to the strong influence due to buoyancy, the migration of dispersed bubbles towards the top wall of the horizontal pipe generally causes a highly asymmetrical internal phase distributions, which are not experienced in vertical bubbly flow. In this study, the internal phase distribution of air-water bubbly flow in a long horizontal pipe with an inner diameter of 50.3 mm has been predicted using the population balance model based on direct quadrature method of moments (DQMOM) and multiple-size group (MUSIG) model. The predicted local radial distributions of gas void fraction, liquid velocity and interfacial area concentration have been validated against the experimental data of Kocamustafaogullari and Huang (1994). In general, satisfactory agreements between predicted and measured results were achieved. The numerical results indicated that the gas void fraction and interfacial area concentration have a unique internal structure with a prevailing maximum peak near the top wall of the pipe due to buoyancy effect. PMID:24415823

  10. Smart licensing and environmental flows: Modeling framework and sensitivity testing

    NASA Astrophysics Data System (ADS)

    Wilby, R. L.; Fenn, C. R.; Wood, P. J.; Timlett, R.; Lequesne, T.

    2011-12-01

    Adapting to climate change is just one among many challenges facing river managers. The response will involve balancing the long-term water demands of society with the changing needs of the environment in sustainable and cost effective ways. This paper describes a modeling framework for evaluating the sensitivity of low river flows to different configurations of abstraction licensing under both historical climate variability and expected climate change. A rainfall-runoff model is used to quantify trade-offs among environmental flow (e-flow) requirements, potential surface and groundwater abstraction volumes, and the frequency of harmful low-flow conditions. Using the River Itchen in southern England as a case study it is shown that the abstraction volume is more sensitive to uncertainty in the regional climate change projection than to the e-flow target. It is also found that "smarter" licensing arrangements (involving a mix of hands off flows and "rising block" abstraction rules) could achieve e-flow targets more frequently than conventional seasonal abstraction limits, with only modest reductions in average annual yield, even under a hotter, drier climate change scenario.

  11. Distribution of resistive body-force in curved free-surface flow

    NASA Technical Reports Server (NTRS)

    Sivakumaran, N. S.; Dressler, R. F.

    1986-01-01

    The customary procedure for including resistive effects in turbulent hydraulic and stratified atmospheric flows is to integrate the empirically-known boundary shears over the entire wetted boundary of a thin fluid slab. A resistive body-force is then assumed to exist everywhere in each slab to replace the boundary shearing force. For the classical Saint-Venant (1871) model, this body-force can be shown to have a constant distribution in the vertical direction, and therefore can be evaluated for use in the momentum differential equation. In the newer Dressler theory (1978), however, for unsteady flow over curved beds, it is proved here that a constant body-force distribution is not possible. Its variable distribution is determined as well as its magnitude for use in the curved-flow equations. This variable distribution acts to produce an equal resultant in every thin layer of fluid parallel to the bed in an angular wedge over the curved channel bed. The new curved-flow equations are therefore extended to include resistive effects.

  12. Burnout and distribution of liquid between the flow core and wall films in narrow slot channels

    NASA Astrophysics Data System (ADS)

    Boltenko, E. A.; Shpakovskii, A. A.

    2010-03-01

    Previous works on studying distribution of liquid between the flow core and wall films in narrow slot channels are briefly reviewed. Interrelation between mass transfer processes and burnout is shown. A procedure for calculating burnout on convex and concave heat-transfer surfaces in narrow slot channels is presented.

  13. LABORATORY AND NUMERICAL INVESTIGATIONS OF RESIDENCE TIME DISTRIBUTION OF FLUIDS IN LAMINAR FLOW STIRRED ANNULAR PHOTOREACTOR

    EPA Science Inventory

    Laboratory and Numerical Investigations of Residence Time Distribution of Fluids in Laminar Flow Stirred Annular Photoreactor

    E. Sahle-Demessie1, Siefu Bekele2, U. R. Pillai1

    1U.S. EPA, National Risk Management Research Laboratory
    Sustainable Technology Division,...

  14. An effective hybrid immune algorithm for solving the distributed permutation flow-shop scheduling problem

    NASA Astrophysics Data System (ADS)

    Xu, Ye; Wang, Ling; Wang, Shengyao; Liu, Min

    2014-09-01

    In this article, an effective hybrid immune algorithm (HIA) is presented to solve the distributed permutation flow-shop scheduling problem (DPFSP). First, a decoding method is proposed to transfer a job permutation sequence to a feasible schedule considering both factory dispatching and job sequencing. Secondly, a local search with four search operators is presented based on the characteristics of the problem. Thirdly, a special crossover operator is designed for the DPFSP, and mutation and vaccination operators are also applied within the framework of the HIA to perform an immune search. The influence of parameter setting on the HIA is investigated based on the Taguchi method of design of experiment. Extensive numerical testing results based on 420 small-sized instances and 720 large-sized instances are provided. The effectiveness of the HIA is demonstrated by comparison with some existing heuristic algorithms and the variable neighbourhood descent methods. New best known solutions are obtained by the HIA for 17 out of 420 small-sized instances and 585 out of 720 large-sized instances.

  15. The effect of structural and rheological properties on blood flow distributions in capillary networks

    NASA Astrophysics Data System (ADS)

    Goldman, Daniel

    2001-11-01

    In various tissues microvascular structure, both geometric and topological, has been shown to be an important determinant of microcirculatory hemodynamics. In addition, blood rheology affects flow and hematocrit distributions in the microcirculation. Here we study steady-state hemodynamics in capillary networks modeled on the three-dimensional structure of the hamster cheek pouch retractor muscle. Capillary diameter is fixed while other structural properties are varied and an ensemble of similar random networks is generated for each parameter set. Using an experimentally derived two-phase continuum model for the flow of blood plasma and red cells, we investigate the effects of network size and topology on blood flow distributions and their variability. We also use typical capillary network structures to examine the importance of rheological effects under varying conditions. Our results indicate the relative importance of microvascular structure and blood rheology in determining the hemodynamic properties of capillary networks in striated muscle.

  16. CFD prediction of flow and phase distribution in fuel assemblies with spacers

    SciTech Connect

    Anglart, H.; Nylund, O.; Kurul, N.

    1995-09-01

    This paper is concerned with the modeling and computation of multi-dimensional two-phase flows in BWR fuel assemblies. The modeling principles are presented based on using a two-fluid model in which lateral interfacial effects are accounted for. This model has been used to evaluate the velocity fields of both vapor and liquid phases, as well as phase distribution, between fuel elements in geometries similar to BWR fuel bundles. Furthermore, this model has been used to predict, in a detailed mechanistic manner, the effects of spacers on flow and phase distribution between, and pressure drop along, fuel elements. The related numerical simulations have been performed using a CFD computer code, CFDS-FLOW3D.

  17. Improved CFD Model to Predict Flow and Temperature Distributions in a Blast Furnace Hearth

    NASA Astrophysics Data System (ADS)

    Komiyama, Keisuke M.; Guo, Bao-Yu; Zughbi, Habib; Zulli, Paul; Yu, Ai-Bing

    2014-10-01

    The campaign life of a blast furnace is limited by the erosion of hearth refractories. Flow and temperature distributions of the liquid iron have a significant influence on the erosion mechanism. In this work, an improved three-dimensional computational fluid dynamics model is developed to simulate the flow and heat transfer phenomena in the hearth of BlueScope's Port Kembla No. 5 Blast Furnace. Model improvements feature more justified input parameters in turbulence modeling, buoyancy modeling, wall boundary conditions, material properties, and modeling of the solidification of iron. The model is validated by comparing the calculated temperatures with the thermocouple data available, where agreements are established within ±3 pct. The flow distribution in the hearth is discussed for intact and eroded hearth profiles, for sitting and floating coke bed states. It is shown that natural convection affects the flow in several ways: for example, the formation of (a) stagnant zones preventing hearth bottom from eroding or (b) the downward jetting of molten liquid promoting side wall erosion, or (c) at times, a vortex-like peripheral flow, promoting the "elephant foot" type erosion. A significant influence of coke bed permeability on the macroscopic flow pattern and the refractory temperature is observed.

  18. Pulmonary blood flow distribution in sheep: effects of anesthesia, mechanical ventilation, and change in posture

    NASA Technical Reports Server (NTRS)

    Walther, S. M.; Domino, K. B.; Glenny, R. W.; Hlastala, M. P.

    1997-01-01

    BACKGROUND: Recent studies providing high-resolution images of pulmonary perfusion have questioned the classical zone model of pulmonary perfusion. Hence the present work was undertaken to provide detailed maps of regional pulmonary perfusion to examine the influence of anesthesia, mechanical ventilation, and posture. METHODS: Pulmonary perfusion was analyzed with intravenous fluorescent microspheres (15 microm) in six sheep studied in four conditions: prone and awake, prone with pentobarbital-anesthesia and breathing spontaneously, prone with anesthesia and mechanical ventilation, and supine with anesthesia and mechanical ventilation. Lungs were air dried at total lung capacity and sectioned into approximately 1,100 pieces (about 2 cm3) per animal. The pieces were weighed and assigned spatial coordinates. Fluorescence was read on a spectrophotometer, and signals were corrected for piece weight and normalized to mean flow. Pulmonary blood flow heterogeneity was assessed using the coefficient of variation of flow data. RESULTS: Pentobarbital anesthesia and mechanical ventilation did not influence perfusion heterogeneity, but heterogeneity increased when the animals were in the supine posture (P < 0.01). Gravitational flow gradients were absent in the prone position but present in the supine (P < 0.001 compared with zero). Pulmonary perfusion was distributed with a hilar-to-peripheral gradient in animals breathing spontaneously (P < 0.05). CONCLUSIONS: The influence of pentobarbital anesthesia and mechanical ventilation on pulmonary perfusion heterogeneity is small compared with the effect of changes in posture. Analysis of flow gradients indicate that gravity plays a small role in determining pulmonary blood flow distribution.

  19. A disaggregation theory for predicting concentration gradient distributions in heterogeneous flows

    NASA Astrophysics Data System (ADS)

    Le Borgne, Tanguy; Huck, Peter; Dentz, Marco; Villermaux, Emmanuel

    2016-04-01

    Many transport processes occurring in fluid flows depend on concentration gradients, including a wide range of chemical reactions, such as mixing-driven precipitation, and biological processes, such as chemotaxis. A general framework for predicting the distribution of concentration gradients in heterogeneous flow fields is proposed based on a disaggregation theory. The evolution of concentration fields under the combined action of heterogeneous advection and diffusion is quantified from the analysis of the development and aggregation of elementary lamellar structures, which naturally form under the stretching action of flow fields. Therefore spatial correlations in concentrations can be estimated based on the understanding of the lamellae aggregation process that determine the concentration levels at neighboring spatial locations. Using this principle we quantify the temporal evolution of the concentration gradient Probability Density Functions in heterogeneous Darcy fields for arbitrary Peclet numbers. This approach is shown to provide accurate predictions of concentration gradient distributions for a range of flow systems, including turbulent flows and low Reynolds number porous media flows, for confined and dispersing mixtures.

  20. Spatio-temporal soil moisture distribution and subsurface water flow in the Shale Hills Catchment

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Lin, H.; Zhu, Q.

    2006-12-01

    Systematic and dynamic soil moisture monitoring is needed to characterize areal soil moisture distribution and model subsurface water flow at various scales. Further understanding of soil-water interactions is the key to explore subsurface water flow and its pathways. Hydropedologic approaches integrating soils information with hydrological processes were used to investigate subsurface water flow (vertical and lateral) and possible flow pathways in the 7.9-ha Shale Hills Catchment in central Pennsylvania. Automatic monitoring systems were installed at seven sites using an array of soil matric potential probes (Campbell Scientific 229 and Decagon matric potential probes) and water content probes (Decagon ECH2O-5). These sites are distributed at different landforms (hilltop, hillslope, and valley floor), representing five soil series (Berks, Blairton, Ernest, Rushtown, Weikert). Probes were inserted at different soil depths as well as their interfaces. The positions of probe installation were designed based on site-specific soil morphology and soil properties from laboratory analysis (e.g., soil texture, bulk density, hydraulic conductivity, water retention). A rain gauge was also installed at each monitoring site. The results showed that different soil types, even different soil layers of the same soil type, displayed different hydrological behaviors. There were evidences that lateral flow contributes to the water flow in the Shale Hills Catchment.

  1. Groundwater flow characterization in a fractured bedrock aquifer using active DTS tests in sealed boreholes

    NASA Astrophysics Data System (ADS)

    Coleman, Thomas I.; Parker, Beth L.; Maldaner, Carlos H.; Mondanos, Michael J.

    2015-09-01

    In recent years, wireline temperature profiling methods have evolved to offer new insight into fractured rock hydrogeology. Important advances in wireline temperature logging in boreholes make use of active line source heating alone and then in combination with temporary borehole sealing with flexible impervious fabric liners to eliminate the effects of borehole cross-connection and recreate natural flow conditions. Here, a characterization technique was developed based on combining fiber optic distributed temperature sensing (DTS) with active heating within boreholes sealed with flexible borehole liners. DTS systems provide a temperature profiling method that offers significantly enhanced temporal resolution when compared with conventional wireline trolling-based techniques that obtain a temperature-depth profile every few hours. The ability to rapidly and continuously collect temperature profiles can better our understanding of transient processes, allowing for improved identification of hydraulically active fractures and determination of relative rates of groundwater flow. The advantage of a sealed borehole environment for DTS-based investigations is demonstrated through a comparison of DTS data from open and lined conditions for the same borehole. Evidence for many depth-discrete active groundwater flow features under natural gradient conditions using active DTS heat pulse testing is presented along with high resolution geologic and geophysical logging and hydraulic datasets. Implications for field implementation are discussed.

  2. The application of flow cytometry to histocompatibility testing.

    PubMed

    Horsburgh, T; Martin, S; Robson, A J

    2000-03-01

    Flow cytometry is a powerful technique that enables the sensitive and quantitative detection of both cellular antigens and bound biological moieties. This article reviews how flow cytometry is increasingly being used as histocompatibility laboratories for the analysis of antibody specificity and HLA antigen expression. A basic description of flow cytometry principles and standardisation is given, together with an outline of clinical application in the areas of pre-transplant cross-matching, antibody screening, post-transplant antibody monitoring and HLA-B27 detection. It is concluded that flow cytometry is a useful multi-parametric analytical tool, yielding clinical benefit especially in the identification of patients at risk of early transplant rejection. PMID:10834606

  3. Spatial distribution of pulmonary blood flow in dogs in increased force environments

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. F.; Ritman, E. L.; Chevalier, P. A.; Sass, D. J.; Wood, E. H.

    1978-01-01

    Spatial distribution of pulmonary blood flow during 2- to 3-min exposures to 6-8 Gy acceleration was studied, using radioactive microspheres in dogs, and compared to previously reported 1 Gy control distributions. Isotope distributions were measured by scintiscanning individual 1-cm-thick cross sections of excised, fixed lungs. Results indicate: (1) the fraction of cardiac output traversing left and right lungs did not change systematically with the duration and magnitude of acceleration; but (2) the fraction is strongly affected by the occurrence or absence of fast deep breaths, which cause an increase or decrease, respectively, in blood flow through the dependent lung; and (3) Gy acceleration caused a significant increase in relative pulmonary vascular resistance (PVR) in nondependent and dependent regions of the lung concurrent with a decrease in PVR in the midsagittal region of the thorax.

  4. A goodness-of-fit test of student distributions based on Rényi entropy

    NASA Astrophysics Data System (ADS)

    Lequesne, Justine

    2015-01-01

    The non-standard Student distributions maximize Rényi entropy among all distributions having a fixed variance. Based on this maximum entropy property, we construct a goodness-of-fit test for testing composite null hypotheses of the non-standard Student distributions. The proposed test thus generalizes the goodness-of-fit tests based on Shannon entropy introduced by O. Vasicek in 1976 for testing normality.

  5. Effect of gravitational and inertial forces on vertical distribution of pulmonary blood flow

    NASA Technical Reports Server (NTRS)

    Chevalier, P. A.; Reed, J. H., Jr.; Vandenberg, R. A.; Wood, E. H.

    1978-01-01

    Vertical distribution of pulmonary blood flow (VDPBF) was studied, using radioactive microsphere emboli, in dogs without thoracotomy in the right decubitus position during exposure to lateral accelerations of 1, 2, 4, and 6 G. At all levels of force environment studied, an inverse linear relationship was observed between vertical height in the thorax and pulmonary blood flow (ml/min/ml lung tissue) with a decrease in flow to the most dependent region of the lung despite large increases in intravascular pressures at this site. Changes in blood flow were smallest at the mid-lung level, the hydrostatic 'balance point' for vascular and pleural pressures. These force environment-dependent changes in VDPBF are not readily explainable by the Starling resistor analog. Gravity-dependent regional differences in pleural and associated interstitial pressures, plus possible changes in vascular tone resulting from inadequate aeration of blood in the most dependent regions of the lung, probably also affect VDPBF.

  6. Experimental evaluation of wall Mach number distributions of the octagonal test section proposed for NASA Lewis Research Center's altitude wind tunnel

    NASA Technical Reports Server (NTRS)

    Harrington, Douglas E.; Burley, Richard R.; Corban, Robert R.

    1986-01-01

    Wall Mach number distributions were determined over a range of test-section free-stream Mach numbers from 0.2 to 0.92. The test section was slotted and had a nominal porosity of 11 percent. Reentry flaps located at the test-section exit were varied from 0 (fully closed) to 9 (fully open) degrees. Flow was bled through the test-section slots by means of a plenum evacuation system (PES) and varied from 0 to 3 percent of tunnel flow. Variations in reentry flap angle or PES flow rate had little or no effect on the Mach number distributions in the first 70 percent of the test section. However, in the aft region of the test section, flap angle and PES flow rate had a major impact on the Mach number distributions. Optimum PES flow rates were nominally 2 to 2.5 percent wtih the flaps fully closed and less than 1 percent when the flaps were fully open. The standard deviation of the test-section wall Mach numbers at the optimum PES flow rates was 0.003 or less.

  7. Experimental study of lock-exchange gravity currents: Coupling between particle distributions and flow structures

    NASA Astrophysics Data System (ADS)

    Su, Zhuang; Peng, Ming; Yuan, Huijing; Lee, Cunbiao

    2014-11-01

    This work presents detailed experimental investigations of the interactions between the particles and flows of the lock-exchange particle-laden gravity currents. A phase Doppler particle analyzer provided non-intrusive and synchronous measurements of the velocities and grain sizes of the particles. High-speed particle image velocimetry was used to measure the flow fields. The measurements showed that the particle behavior and the currents were intricately coupled. Particle distributions at different parts of the current are given, showing that the particles' behaviors are highly related to the flow fields. The influences of the grain size to the flow fields are also investigated by comparing flow fields of currents carrying different particles to each other, as well as the un-laden currents. The presence of particles seems to postpone the evolving of the flow structures, it weakens the vorticity of the shear layer in the head but strengthens the voriticty in the body or tail of the currents. The influences to the flow fields increases with the grain size. This work was supported by the National Natural Science Foundation of China under Grant No. 109103010062. This work was also supported by the National Climb- B Plan under Grant No. 2009CB724100.

  8. Viscoelastic flow-focusing in microchannels: scaling properties of the particle radial distributions.

    PubMed

    Romeo, Giovanni; D'Avino, Gaetano; Greco, Francesco; Netti, Paolo A; Maffettone, Pier Luca

    2013-07-21

    Particles suspended in non-Newtonian liquids flowing in channels may migrate transversally to the main flow direction as a result of normal stress gradients. Viscoelasticity-induced migration has proven to be an efficient mechanism to promote 3D flow-focusing in cylindrical microchannels, avoiding the need for complex and expensive apparati. In this work, we demonstrate the existence of a single dimensionless number (Θ) that governs the migration dynamics of particles in viscoelastic liquids flowing in micropipes at low Deborah numbers (Deborah number is the ratio of fluid and flow characteristic times). The definition of Θ in terms of the relevant fluid, flow and geometrical quantities is obtained by generalizing the particle migration velocity expression given in previous asymptotic analytical theories through numerical simulations. An extensive experimental investigation quantitatively confirms the novel predictions: the experimental particle distributions along the channel axial direction collapse on a single curve when rescaled in terms of the proposed dimensionless number. The results reported in this work give a simple and general way to define the flow-focusing conditions promoted by viscoelastic effects. PMID:23670133

  9. Testing and Performance Verification of a High Bypass Ratio Turbofan Rotor in an Internal Flow Component Test Facility

    NASA Technical Reports Server (NTRS)

    VanZante, Dale E.; Podboy, Gary G.; Miller, Christopher J.; Thorp, Scott A.

    2009-01-01

    A 1/5 scale model rotor representative of a current technology, high bypass ratio, turbofan engine was installed and tested in the W8 single-stage, high-speed, compressor test facility at NASA Glenn Research Center (GRC). The same fan rotor was tested previously in the GRC 9x15 Low Speed Wind Tunnel as a fan module consisting of the rotor and outlet guide vanes mounted in a flight-like nacelle. The W8 test verified that the aerodynamic performance and detailed flow field of the rotor as installed in W8 were representative of the wind tunnel fan module installation. Modifications to W8 were necessary to ensure that this internal flow facility would have a flow field at the test package that is representative of flow conditions in the wind tunnel installation. Inlet flow conditioning was designed and installed in W8 to lower the fan face turbulence intensity to less than 1.0 percent in order to better match the wind tunnel operating environment. Also, inlet bleed was added to thin the casing boundary layer to be more representative of a flight nacelle boundary layer. On the 100 percent speed operating line the fan pressure rise and mass flow rate agreed with the wind tunnel data to within 1 percent. Detailed hot film surveys of the inlet flow, inlet boundary layer and fan exit flow were compared to results from the wind tunnel. The effect of inlet casing boundary layer thickness on fan performance was quantified. Challenges and lessons learned from testing this high flow, low static pressure rise fan in an internal flow facility are discussed.

  10. Operational evaluation of a proppeller test stand in the quiet flow facility at Langley Research Center

    NASA Technical Reports Server (NTRS)

    Block, P. J. W.

    1982-01-01

    Operational proof tests of a propeller test stand (PTS) in a quiet flow facility (QFF) are presented. The PTS is an experimental test bed for acoustic propeller research in the quiet flow environment of the QFF. These proof tests validate thrust and torque predictions, examine the repeatability of measurements on the PTS, and determine the effect of applying artificial roughness to the propeller blades. Since a thrusting propeller causes an open jet to contract, the potential flow core was surveyed to examine the magnitude of the contraction. These measurements are compared with predicted values. The predictions are used to determine operational limitations for testing a given propeller design in the QFF.

  11. Aircraft wake flow effect and horizontal tail buffet. [pressure distribution and responses of fighter aircraft in transonic maneuvers

    NASA Technical Reports Server (NTRS)

    Hwang, C.; Pi, W. S.

    1979-01-01

    As part of a program to investigate the fluctuating pressure distribution and response behavior of a fighter aircraft in transonic maneuver, an F-5A scale model has previously been tested in an 11-ft transonic wind tunnel. The model, with a number of static and dynamic pressure transducers imbedded in the lifting surfaces was tested at various angles of attack up to 16 deg. In this paper, test results of particular interest to wake flow and horizontal tail buffet are described. It is shown that the dynamic pressure data on the tail surface at the specified flight conditions serve to determine the local dynamic loads. They also influence the control performance of the aircraft under maneuver conditions where buffet is encountered. The data presented demonstrate a number of contributing factors that affect the tail dynamic pressures in the transonic regime.

  12. Biodegradable radiopaque microspheres for the evaluation of regional pulmonary blood flow distribution using electron-beam computed tomography

    NASA Astrophysics Data System (ADS)

    Workman, Michael J.; Tajik, Jehangir K.; Robinson, Miguel T.; Hoffman, Eric A.

    1994-05-01

    Accurate measurement of regional pulmonary blood flow distribution is of interest both as a research and diagnostic tool. Measurements of regional pulmonary perfusion via x-ray CT offer the possibility of detecting perfusion deficits due to pulmonary embolus while maintaining a high degree of anatomic detail. Use of bolus injection of conventional radiopaque contrast with associated short mean transit times (5 - 7 seconds), requires a high degree of temporal resolution offered clinically only by electron beam x-ray CT (Imatron). The present study was intended to characterize biodegradable radiopaque microspheres as an alternative contrast agent which would allow for measurement of regional pulmonary blood flow with scanning times associated with conventional or spiral thin slice, volumetric x-ray CT protocols. To test this, a dog was scanned at 6 slice levels and 13 time points with image acquisition gated to the cardiac cycle. Lung volumes were maintained at functional residual capacity.

  13. Static and Wind Tunnel Aero-Performance Tests of NASA AST Separate Flow Nozzle Noise Reduction Configurations

    NASA Technical Reports Server (NTRS)

    Mikkelsen, Kevin L.; McDonald, Timothy J.; Saiyed, Naseem (Technical Monitor)

    2001-01-01

    This report presents the results of cold flow model tests to determine the static and wind tunnel performance of several NASA AST separate flow nozzle noise reduction configurations. The tests were conducted by Aero Systems Engineering, Inc., for NASA Glenn Research Center. The tests were performed in the Channels 14 and 6 static thrust stands and the Channel 10 transonic wind tunnel at the FluiDyne Aerodynamics Laboratory in Plymouth, Minnesota. Facility checkout tests were made using standard ASME long-radius metering nozzles. These tests demonstrated facility data accuracy at flow conditions similar to the model tests. Channel 14 static tests reported here consisted of 21 ASME nozzle facility checkout tests and 57 static model performance tests (including 22 at no charge). Fan nozzle pressure ratio varied from 1.4 to 2.0, and fan to core total pressure ratio varied from 1.0 to 1.19. Core to fan total temperature ratio was 1.0. Channel 10 wind tunnel tests consisted of 15 tests at Mach number 0.28 and 31 tests at Mach 0.8. The sting was checked out statically in Channel 6 before the wind tunnel tests. In the Channel 6 facility, 12 ASME nozzle data points were taken and 7 model data points were taken. In the wind tunnel, fan nozzle pressure ratio varied from 1.73 to 2.8, and fan to core total pressure ratio varied from 1.0 to 1.19. Core to fan total temperature ratio was 1.0. Test results include thrust coefficients, thrust vector angle, core and fan nozzle discharge coefficients, total pressure and temperature charging station profiles, and boat-tail static pressure distributions in the wind tunnel.

  14. Characterizing fractured rock aquifers using heated Distributed Fiber-Optic Temperature Sensing to determine borehole vertical flow

    NASA Astrophysics Data System (ADS)

    Read, T. O.; Bour, O.; Selker, J. S.; Le Borgne, T.; Bense, V.; Hochreutener, R.; Lavenant, N.

    2013-12-01

    In highly heterogeneous media, fracture network connectivity and hydraulic properties can be estimated using methods such as packer- or cross-borehole pumping-tests. Typically, measurements of hydraulic head or vertical flow in such tests are made either at a single location over time, or at a series of depths by installing a number of packers or raising or lowering a probe. We show how this often encountered monitoring problem, with current solutions sacrificing either one of temporal or spatial information, can be addressed using Distributed Temperature Sensing (DTS). Here, we electrically heat the conductive cladding materials of cables deployed in boreholes to determine the vertical flow profile. We present results from heated fiber optic cables deployed in three boreholes in a fractured rock aquifer at the much studied experimental site near Ploemeur, France, allowing detailed comparisons with alternative methods (e.g. Le Borgne et al., 2007). When submerged in water and electrically heated, the cable very rapidly reaches a steady state temperature (less than 60 seconds). The steady state temperature of the heated cable, measured using the DTS method, is then a function of the velocity of the fluid in the borehole. We find that such cables are sensitive to a wide range of fluid velocities, and thus suitable for measuring both ambient and pumped flow profiles at the Ploemeur site. The cables are then used to monitor the flow profiles during all possible configurations of: ambient flow, cross-borehole- (pumping one borehole, and observing in another), and dipole-tests (pumping one borehole, re-injection in another). Such flow data acquired using DTS may then be used for tomographic flow inversions, for instance using the approach developed by Klepikova et al., (submitted). Using the heated fiber optic method, we are able to observe the flow response during such tests in high spatial detail, and are also able to capture temporal flow dynamics occurring at the

  15. Numerical characterization of the hydrodynamics and thermal behavior of air flow in flexible air distribution system

    NASA Astrophysics Data System (ADS)

    Gharehdaghi, Samad; Moujaes, Samir

    2013-10-01

    Flexible duct air distribution systems are used in a large percentage of residential and small commercial buildings in the United States . Very few empirical or predictive data are available though to help provide the HVAC design engineer with reliable information . Moreover, because of the ducts flexibility, the shapes of these ducts offer a different set of operating fluid flow and thermal conditions from traditional smooth metal ducts. Hence, both the flow field and heat transfer through this kind of ducts are much more complex and merit to be analyzed from a numerical predictive approach. The aim of this research paper is to compute some of the hydrodynamic and heat transfer characteristics of the air flow inside these ducts over a range of Re numbers commonly used in the flow conditions of these air distribution systems. The information resulting from this CFD simulation, where a κ-ɛ turbulent model is used to predict the flow conditions, provide pressure drop and average convective heat transfer coefficients that exist in these ducts and was compared to previously found data. Circulation zones in the depressions of these ducts are found to exist which are suspected of influencing the pressured drop and heat transfer coefficients as compared to smooth ducts. The results show that fully developed conditions exist much earlier with regard to the inlet for both hydrodynamic and thermal entrance regions than what would be expected in smooth ducts under the same turbulent conditions.

  16. High resolution gamma ray tomography scanner for flow measurement and non-destructive testing applications

    SciTech Connect

    Hampel, U.; Bieberle, A.; Hoppe, D.; Kronenberg, J.; Schleicher, E.; Suehnel, T.; Zimmermann, F.; Zippe, C.

    2007-10-15

    We report on the development of a high resolution gamma ray tomography scanner that is operated with a Cs-137 isotopic source at 662 keV gamma photon energy and achieves a spatial image resolution of 0.2 line pairs/mm at 10% modulation transfer function for noncollimated detectors. It is primarily intended for the scientific study of flow regimes and phase fraction distributions in fuel element assemblies, chemical reactors, pipelines, and hydrodynamic machines. Furthermore, it is applicable to nondestructive testing of larger radiologically dense objects. The radiation detector is based on advanced avalanche photodiode technology in conjunction with lutetium yttrium orthosilicate scintillation crystals. The detector arc comprises 320 single detector elements which are operated in pulse counting mode. For measurements at fixed vessels or plant components, we built a computed tomography scanner gantry that comprises rotational and translational stages, power supply via slip rings, and data communication to the measurement personal computer via wireless local area network.

  17. High resolution gamma ray tomography scanner for flow measurement and non-destructive testing applications

    NASA Astrophysics Data System (ADS)

    Hampel, U.; Bieberle, A.; Hoppe, D.; Kronenberg, J.; Schleicher, E.; Sühnel, T.; Zimmermann, F.; Zippe, C.

    2007-10-01

    We report on the development of a high resolution gamma ray tomography scanner that is operated with a Cs-137 isotopic source at 662keV gamma photon energy and achieves a spatial image resolution of 0.2linepairs/mm at 10% modulation transfer function for noncollimated detectors. It is primarily intended for the scientific study of flow regimes and phase fraction distributions in fuel element assemblies, chemical reactors, pipelines, and hydrodynamic machines. Furthermore, it is applicable to nondestructive testing of larger radiologically dense objects. The radiation detector is based on advanced avalanche photodiode technology in conjunction with lutetium yttrium orthosilicate scintillation crystals. The detector arc comprises 320 single detector elements which are operated in pulse counting mode. For measurements at fixed vessels or plant components, we built a computed tomography scanner gantry that comprises rotational and translational stages, power supply via slip rings, and data communication to the measurement personal computer via wireless local area network.

  18. Experimental testing of flexible barriers for containment of debris flows

    USGS Publications Warehouse

    DeNatale, Jay S.; Iverson, Richard M.; Major, Jon J.; LaHusen, Richard G.; Fliegel, Gregg L.; Duffy, John D.

    1999-01-01

    In June 1996, six experiments conducted at the U.S. Geological Survey Debris Flow Flume demonstrated that flexible, vertical barriers constructed of wire rope netting can stop small debris flows. All experimental debris flows consisted of water-saturated gravelly sand with less than two percent finer sediment by weight. All debris flows had volumes of about 10 cubic meters, masses of about 20 metre tons, and impact velocities of 5 to 9 meters per second. In four experiments, the debris flow impacted pristine, unreformed barriers of varying design; in the other two experiments, the debris flow impacted barriers already loaded with sediment from a previous flow. Differences in barrier design led to differences in barrier performance. Experiments were conducted with barriers constructed of square-mesh wire-rope netting with 30centimeter, 20centimeter, and 15 centimeter mesh openings as well as 30centimeter diameter interlocking steel rings. In all cases, sediment cascading downslope at the leading edge of the debris flows tended to spray through the nets. Nets fitted with finer-mesh chain link or chicken wire liners contained more sediment than did unlined nets, and a ring net fitted with a synthetic silt screen liner contained nearly 100 percent of the sediment. Irreversible net displacements of up to 2 meters and friction brake engagement on the support and anchor cables dissipated some of the impact energy. However, substantial forces developed in the steel support columns and the lateral and tie-back anchor cables attached to these columns. As predicted by elementary mechanics, the anchor cables experienced larger tensile forces when the support columns were hinged at the base rather than bolted rigidly to the foundation. Measured loads in the lateral anchor cables exceeded those in the tie-back anchor cables and the load cell capacity of 45 kilo-Newtons. Measurements also indicated that the peak loads in the tie- back anchors were highly transient and occurred at

  19. Performance testing of a Savonius windmill rotor in shear flows

    NASA Astrophysics Data System (ADS)

    Mojola, O. O.; Onasanya, O. E.

    The effects of flow shear and/or unsteady behavior on the power generation capability of a Savonius wind turbine rotor are assessed in view of measurements conducted, both in two statistically steady shear flows and in the wind, of rotor tip speed and torque at a number of streamwise stations for each of four values of the rotor bucket overlap ratio. It is found that, even in the absence of shear, the power coefficient of a Savonius wind turbine rotor is most strongly dependent on tip speed ratio.

  20. An innovative approach to supplying an environment for the integration and test of the Space Station distributed avionics systems

    NASA Technical Reports Server (NTRS)

    Barry, Thomas; Scheffer, Terrance; Small, L. R.

    1988-01-01

    This paper describes an innovative approach to supplying an environment for the integration and testing of the Space Station distributed avionics systems. The environment's relationship to the process flow of the Space Station verification from systems development to on-orbit verification is presented. This paper also describes the uses of the environment's hardware implementation called Data Management System (DMS) kits. The way in which this environment allows system developers to independently verify their system's performance, fault detection, and recovery capability is explained.

  1. Measured and calculated acoustic attenuation rates of tuned resonator arrays for two surface impedance distribution models with flow

    NASA Technical Reports Server (NTRS)

    Parrott, Tony L.; Abrahamson, A. Louis; Jones, Michael G.

    1988-01-01

    An experiment was performed to validate two analytical models for predicting low frequency attenuation of duct liner configurations built from an array of seven resonators that could be individually tuned via adjustable cavity depths. These analytical models had previously been developed for high frequency aero-engine inlet duct liner design. In the low frequency application, the liner surface impedance distribution is unavoidably spatially varying by virtue of available fabrication techniques. The characteristic length of this spatial variation may be a significant fraction of the acoustic wavelength. Comparison of measured and predicted attenuation rates and transmission losses for both modal decomposition and finite element propagation models were in good to excellent agreement for a test frequency range that included the first and second cavity resonance frequencies. This was true for either of two surface impedance distribution modeling procedures used to simplify the impedance boundary conditions. In the presence of mean flow, measurements revealed a fine scale structure of acoustic hot spots in the attenuation and phase profiles. These details were accurately predicted by the finite element model. Since no impedance changes due to mean flow were assumed, it is concluded that this fine scale structure was due to convective effects of the mean flow interacting with the surface impedance nonuniformities.

  2. Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic Conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

    USGS Publications Warehouse

    Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.

    2010-01-01

    Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative

  3. Interpretation of Flow Logs from Nevada Test Site Boreholes to Estimate Hydraulic conductivity Using Numerical Simulations Constrained by Single-Well Aquifer Tests

    SciTech Connect

    Garcia, C. Amanda; Halford, Keith J.; Laczniak, Randell J.

    2010-02-12

    Hydraulic conductivities of volcanic and carbonate lithologic units at the Nevada Test Site were estimated from flow logs and aquifer-test data. Borehole flow and drawdown were integrated and interpreted using a radial, axisymmetric flow model, AnalyzeHOLE. This integrated approach is used because complex well completions and heterogeneous aquifers and confining units produce vertical flow in the annular space and aquifers adjacent to the wellbore. AnalyzeHOLE simulates vertical flow, in addition to horizontal flow, which accounts for converging flow toward screen ends and diverging flow toward transmissive intervals. Simulated aquifers and confining units uniformly are subdivided by depth into intervals in which the hydraulic conductivity is estimated with the Parameter ESTimation (PEST) software. Between 50 and 150 hydraulic-conductivity parameters were estimated by minimizing weighted differences between simulated and measured flow and drawdown. Transmissivity estimates from single-well or multiple-well aquifer tests were used to constrain estimates of hydraulic conductivity. The distribution of hydraulic conductivity within each lithology had a minimum variance because estimates were constrained with Tikhonov regularization. AnalyzeHOLE simulated hydraulic-conductivity estimates for lithologic units across screened and cased intervals are as much as 100 times less than those estimated using proportional flow-log analyses applied across screened intervals only. Smaller estimates of hydraulic conductivity for individual lithologic units are simulated because sections of the unit behind cased intervals of the wellbore are not assumed to be impermeable, and therefore, can contribute flow to the wellbore. Simulated hydraulic-conductivity estimates vary by more than three orders of magnitude across a lithologic unit, indicating a high degree of heterogeneity in volcanic and carbonate-rock units. The higher water transmitting potential of carbonate-rock units relative

  4. Single-phase power distribution system power flow and fault analysis

    NASA Technical Reports Server (NTRS)

    Halpin, S. M.; Grigsby, L. L.

    1992-01-01

    Alternative methods for power flow and fault analysis of single-phase distribution systems are presented. The algorithms for both power flow and fault analysis utilize a generalized approach to network modeling. The generalized admittance matrix, formed using elements of linear graph theory, is an accurate network model for all possible single-phase network configurations. Unlike the standard nodal admittance matrix formulation algorithms, the generalized approach uses generalized component models for the transmission line and transformer. The standard assumption of a common node voltage reference point is not required to construct the generalized admittance matrix. Therefore, truly accurate simulation results can be obtained for networks that cannot be modeled using traditional techniques.

  5. Rock size distributions on lava flow surfaces: New results from a range of compositions

    NASA Astrophysics Data System (ADS)

    Burke, M. P.; Anderson, S. W.; Bulmer, M. H.

    2005-12-01

    We measured block sizes along 15-25m orthogonal transects on 12 lava flows of compositions ranging from basalt to rhyolite. At each site, we stretched a line across the flow surface then measured the length of each block cut by this line that were greater than 3-12cm (depending on composition). The measurements from each site were reduced to cumulative size frequency distribution plots, with block size (D) plotted against the fraction of the line f(D) composed of blocks greater than or equal to that size, and fitted with an exponential curve of the form f(D) = k exp(-qD) where k is the intercept and q is the decay parameter. Average block size and geometric mean were also determined for each site. Our data show no clear trends linking average or mean block size to composition, although there does seem to be relationship between block size and the decay parameter. Block size corresponds with the decay parameter at each site except for the basaltic andesite flow at Paint Pot Crater (CA). Many sites at this flow were covered with secondary spatter deposits. Largest blocks and smallest decay parameters were found for the andesite flows at Sabancaya (Peru), while the basalt flows at Cima (CA) exhibited the smallest blocks and largest decay parameters. The second largest block sizes occurred at the four Inyo domes composed of both crystal-rich and glassy rhyolite, and these domes also showed the second smallest decay parameters. All four of the Inyo domes were emplaced along the same feeder dike trend, and the average and mean sizes and decay parameters at these domes are nearly identical, suggesting that composition, extrusion rate, or eruption history controls the block size distributions. However, values for the two andesitic flows, Mt. Shasta (CA) and Sabancaya, were very different, suggesting that extrusion rate and/or eruption history exert a stronger control over the block size distributions than does composition. LIDAR data sets are capable of detecting sub

  6. Dispersed fluid flow in fractured reservoirs: An analysis of tracer-determined residence time distributions

    NASA Astrophysics Data System (ADS)

    Robinson, Bruce A.; Tester, Jefferson W.

    1984-11-01

    A methodology for analyzing the internal flow characteristics of a fractured geothermal reservoir using tracer-determined residence time distribution curves is outlined. Emphasis is placed on comparison of the statistical quantities obtained from the tracer curves of different reservoirs or of the same reservoir under different conditions. In this way, model-independent information may be used unambiguously to construct empirical reservoir performance correlations. Downhole measurements of the tracer response exiting from discrete fracture zones permit further characterization of reservoir fluid flow behavior. Tracer experiments conducted in prototype hot dry rock geothermal reservoirs in fractured rock are examined using these statistically based data analysis methods.

  7. Flow distribution in a roller jet bit determined from hot-wire anemometry measurements

    SciTech Connect

    Gavignet, A.A.; Bradbury, L.J.; Quetier, F.P.

    1987-03-01

    In current practice, the optimization of drilling hydraulics consists of the selection of nozzle sizes that maximize either jet impact or hydraulic power at the nozzle. But what is required for a real optimization is the knowledge of the hydraulic forces available for cleaning at the rock face, not at the nozzle. This paper shows the results of hot-wire anemometry experiments that provide insight into the flow distribution in a jet bit. Direct measurements of the flow field, including turbulence levels, are reported and discussed.

  8. Evaluation of early conception factor lateral flow test to determine nonpregnancy in dairy cattle.

    PubMed

    Ambrose, Divakar J; Radke, Brian; Pitney, Phyllis A; Goonewardene, Laksiri A

    2007-08-01

    The early conception factor (ECF) lateral flow test was evaluated for its ability to accurately determine nonpregnant status in dairy cattle. Results of 2 field trials involving 191 cows and 832 tests indicated the probability that a cow can be correctly diagnosed as nonpregnant by using the ECF test is only about 50%. Agreement of test results between milk and serum obtained from the same cow was 57.5%. The ECF test was not consistent in identifying nonpregnancy when the same cows were tested repeatedly over a period of 4 weeks. We conclude that the ECF lateral flow test does not accurately identify nonpregnancy in dairy cattle. PMID:17824326

  9. Borehole Flow and Contaminant Distribution in Sedimentary-Bedrock Recharge Areas

    NASA Astrophysics Data System (ADS)

    Williams, J. H.

    2005-12-01

    Borehole flow and contaminant distribution has been investigated at a series of VOC-impacted sites in New York, New Jersey, and California that are recharge areas for sandstone, mudstone, and carbonate-bedrock aquifers. At the investigated sites, downward flow occurs through open boreholes that intersect shallow and deep fracture zones having differing hydraulic heads. Detected flows span the dynamic measurement range of 0.03 to 30 liters per minute for high-resolution flowmeters that employ heat-pulse and electromagnetic technologies. Estimated head differences between shallow and deep zones from model simulation of ambient and stressed flow profiles range from one to more than 10 meters, and are in close agreement with differences measured between zones isolated by straddle packers or by multiple-depth well completions. The presence of boreholes that are open temporarily during installation or completed as open holes impacts contaminant distribution and adversely affects the results of ground-water quality sampling programs. In boreholes open to shallow contaminated zones and deep non-contaminated zones, ambient flow diverts dissolved VOCs from the shallow zones down the borehole and into the deep zones. Samples obtained from such boreholes at purge and sampling rates less than the ambient downward flow represent the water quality of the shallow zones regardless of the depths where samples are collected. This can lead to the erroneous interpretation of a deep contaminant plume. Sampling by use of straddle-packer systems with low purge and sampling rates and short-term zone isolation also may indicate deep contamination because of inadequate flushing. Even in deep zones isolated by multiple-depth completions, elevated VOC concentrations linger for many months because of contaminant diffusion into and out of the bedrock matrix. Conversely, in boreholes open to shallow non-contaminated zones and deep contaminated zones, samples collected at rates less than the

  10. Chlorine-36 data at Yucca Mountain: Statistical tests of conceptual models for unsaturated-zone flow

    USGS Publications Warehouse

    Campbell, K.; Wolfsberg, A.; Fabryka-Martin, J.; Sweetkind, D.

    2003-01-01

    An extensive set of chlorine-36 (36Cl) data has been collected in the Exploratory Studies Facility (ESF), an 8-km-long tunnel at Yucca Mountain, Nevada, for the purpose of developing and testing conceptual models of flow and transport in the unsaturated zone (UZ) at this site. At several locations, the measured values of 36Cl/Cl ratios for salts leached from rock samples are high enough to provide strong evidence that at least a small component of bomb-pulse 36Cl, fallout from atmospheric testing of nuclear devices in the 1950s and 1960s, was measured, implying that some fraction of the water traveled from the ground surface through 200-300 m of unsaturated rock to the level of the ESF during the last 50 years. These data are analyzed here using a formal statistical approach based on log-linear models to evaluate alternative conceptual models for the distribution of such fast flow paths. The most significant determinant of the presence of bomb-pulse 36Cl in a sample from the welded Topopah Spring unit (TSw) is the structural setting from which the sample was collected. Our analysis generally supports the conceptual model that a fault that cuts through the nonwelded Paintbrush tuff unit (PTn) that overlies the TSw is required in order for bomb-pulse 36Cl to be transmitted to the sample depth in less than 50 years. Away from PTn-cutting faults, the ages of water samples at the ESF appear to be a strong function of the thickness of the nonwelded tuff between the ground surface and the ESF, due to slow matrix flow in that unit. ?? 2002 Elsevier Science B.V. All rights reserved.

  11. Chlorine-36 data at Yucca Mountain: statistical tests of conceptual models for unsaturated-zone flow.

    PubMed

    Campbell, Katherine; Wolfsberg, Andrew; Fabryka-Martin, June; Sweetkind, Donald

    2003-01-01

    An extensive set of chlorine-36 (36Cl) data has been collected in the Exploratory Studies Facility (ESF), an 8-km-long tunnel at Yucca Mountain, Nevada, for the purpose of developing and testing conceptual models of flow and transport in the unsaturated zone (UZ) at this site. At several locations, the measured values of 36Cl/Cl ratios for salts leached from rock samples are high enough to provide strong evidence that at least a small component of bomb-pulse 36Cl, fallout from atmospheric testing of nuclear devices in the 1950s and 1960s, was measured, implying that some fraction of the water traveled from the ground surface through 200-300 m of unsaturated rock to the level of the ESF during the last 50 years. These data are analyzed here using a formal statistical approach based on log-linear models to evaluate alternative conceptual models for the distribution of such fast flow paths. The most significant determinant of the presence of bomb-pulse 36Cl in a sample from the welded Topopah Spring unit (TSw) is the structural setting from which the sample was collected. Our analysis generally supports the conceptual model that a fault that cuts through the nonwelded Paintbrush tuff unit (PTn) that overlies the TSw is required in order for bomb-pulse 36Cl to be transmitted to the sample depth in less than 50 years. Away from PTn-cutting faults, the ages of water samples at the ESF appear to be a strong function of the thickness of the nonwelded tuff between the ground surface and the ESF, due to slow matrix flow in that unit. PMID:12714284

  12. Testing MODFLOW-LGR for simulating flow around buried Quaternary valleys - synthetic test cases

    NASA Astrophysics Data System (ADS)

    Vilhelmsen, T. N.; Christensen, S.

    2009-12-01

    In this study the Local Grid Refinement (LGR) method developed for MODFLOW-2005 (Mehl and Hill, 2005) is utilized to describe groundwater flow in areas containing buried Quaternary valley structures. The tests are conducted as comparative analysis between simulations run with a globally refined model, a locally refined model, and a globally coarse model, respectively. The models vary from simple one layer models to more complex ones with up to 25 model layers. The comparisons of accuracy are conducted within the locally refined area and focus on water budgets, simulated heads, and simulated particle traces. Simulations made with the globally refined model are used as reference (regarded as “true” values). As expected, for all test cases the application of local grid refinement resulted in more accurate results than when using the globally coarse model. A significant advantage of utilizing MODFLOW-LGR was that it allows increased numbers of model layers to better resolve complex geology within local areas. This resulted in more accurate simulations than when using either a globally coarse model grid or a locally refined model with lower geological resolution. Improved accuracy in the latter case could not be expected beforehand because difference in geological resolution between the coarse parent model and the refined child model contradicts the assumptions of the Darcy weighted interpolation used in MODFLOW-LGR. With respect to model runtimes, it was sometimes found that the runtime for the locally refined model is much longer than for the globally refined model. This was the case even when the closure criteria were relaxed compared to the globally refined model. These results are contradictory to those presented by Mehl and Hill (2005). Furthermore, in the complex cases it took some testing (model runs) to identify the closure criteria and the damping factor that secured convergence, accurate solutions, and reasonable runtimes. For our cases this is judged to

  13. 77 FR 5472 - Pipeline Safety: Expanding the Use of Excess Flow Valves in Gas Distribution Systems to...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-03

    ... FR 72666). The ANPRM sought public comment on several issues related to expanding the use of EFVs in...: Expanding the Use of Excess Flow Valves in Gas Distribution Systems to Applications Other Than Single-Family... Safety: Expanding the Use of Excess Flow Valves (EFVs) in Gas Distribution Systems to Applications...

  14. The Effects of Bottom Blowing Gas Flow Rate Distribution During the Steelmaking Converter Process on Mixing Efficiency

    NASA Astrophysics Data System (ADS)

    Chu, Kuan-Yu; Chen, Hsing-Hao; Lai, Po-Han; Wu, Hsuan-Chung; Liu, Yung-Chang; Lin, Chi-Cheng; Lu, Muh-Jung

    2016-04-01

    Featuring the advantages of top-blown and bottom-blown oxygen converters, top and bottom combined blown converters are mainstream devices used in steelmaking converter. This study adopted the FLUENT software to develop a numerical model that simulates 3D multiphase flows of gas (air and argon), liquid steel, and slag. Ten numerical experiments were conducted to analyze the effects that the bottom blowing gas flow rate distribution patterns (uniform, linear fixed total flow rate, linear fixed maximal flow rate, and V-type) and bottom blowing gas flow distribution gradients of combined blown converters exert on slag surface stirring heights, flow field patterns, simulation system dynamic pressures, mixing time, and liquid steel-slag interface velocity. The simulation results indicated that the mixing efficiency was highest for the linear fixed total flow rate, followed by the linear fixed maximal flow rate, V-type, and uniform patterns. The bottom blowing gas flow rate distribution exhibited linear patterns and large gradients, and high bottom blowing total flow rates increased the mixing efficiency substantially. In addition, the results suggested that even when bottom blowing total flow rate was reduced, adopting effective bottom blowing gas flow rate distribution patterns and gradients could improve the mixing efficiency.

  15. Parameter Estimation and Hypothesis Testing of Two Negative Binomial Distribution Population with Missing Data

    NASA Astrophysics Data System (ADS)

    Zhao, Zhiwen

    Our purpose is to deal with the parameter estimation and hypothesis testing on the equality of two negative binomial distribution populations with missing data. The consistency and asymptotic normality of the estimations are proved. In addition statistic on testing equality of two negative distributions and its limiting distribution are obtained.

  16. Impact of spacing filaments external to hollow fibers on dialysate flow distribution and dialyzer performance.

    PubMed

    Ronco, C; Scabardi, M; Goldoni, M; Brendolan, A; Crepaldi, C; La Greca, G

    1997-05-01

    A new type of dialyzer (PAN 650 SF Asahi) is analyzed in terms of hydraulic properties, solute clearances and dialysate flow distribution. The new type of dialyzer is a polyacrylonitrile hollow fiber filter, equipped with spacing filaments placed externally to the fibers to facilitate dialysate distribution and avoid channeling. The new filter is compared with a similar filter without spacing filaments. For this purpose, blood and dialysate side clearances have been measured in sequential dialysis session carried out randomly in the same patients. Furthermore, a last generation helical scanner (X-Press/HS1, Toshiba) has been utilized to analyze in vitro the flow distribution of dialysate inside the dialyzer. A contrast medium was injected and a sequence of images has been achieved on a longitudinal section of the dialyzer. This new method permits to avoid any bias due to the cylindrical shape of the dialyzer, since a 10 mm thick rectangular section is analyzed and not the entire body of the filter. The dialyzers equipped with spacing filaments displayed a significant improvement of the dialysate distribution as demonstrated by the radiological pattern. In detail, despite a channeling phenomenon in the peripherical region of the bundle is still present, this is remarkably reduced in comparison with the channelling phenomenon observed in the standard dialyzers. This improved distribution is confirmed by a significant improvement of the solute clearances. PMID:9209926

  17. A MILP-Based Distribution Optimal Power Flow Model for Microgrid Operation

    SciTech Connect

    Liu, Guodong; Starke, Michael R; Zhang, Xiaohu; Tomsovic, Kevin

    2016-01-01

    This paper proposes a distribution optimal power flow (D-OPF) model for the operation of microgrids. The proposed model minimizes not only the operating cost, including fuel cost, purchasing cost and demand charge, but also several performance indices, including voltage deviation, network power loss and power factor. It co-optimizes the real and reactive power form distributed generators (DGs) and batteries considering their capacity and power factor limits. The D-OPF is formulated as a mixed-integer linear programming (MILP). Numerical simulation results show the effectiveness of the proposed model.

  18. A compensation-based power flow method for weakly meshed distribution and transmission networks

    SciTech Connect

    Shirmohammadi, D.; Hong, H.W.; Semlyen, A.; Luo, G.X.

    1988-05-01

    This paper describes a new power flow method for solving weakly meshed distribution and transmission networks, using a multi-port compensation technique and basic formulation of Kirchhoff's laws. This method has excellent convergence characteristics and is very robust. A computer program implementing this power flow solution scheme was developed and successfully applied to several practical distribution networks with radial and weakly meshed structure. This program was also successfully used for solving radial and weakly meshed transmission networks. The method can be applied to the solution of both the three-phase (unbalanced) and single-phase (balanced) representation of the network. In this paper, however, only the single phase representation is treated in detail.

  19. A fast approach to designing airfoils from given pressure distribution in compressible flows

    NASA Technical Reports Server (NTRS)

    Daripa, Prabir

    1987-01-01

    A new inverse method for aerodynamic design of airfols is presented for subcritical flows. The pressure distribution in this method can be prescribed as a function of the arc length of the as-yet unknown body. This inverse problem is shown to be mathematically equivalent to solving only one nonlinear boundary value problem subject to known Dirichlet data on the boundary. The solution to this problem determines the airfoil, the freestream Mach number, and the upstream flow direction. The existence of a solution to a given pressure distribution is discussed. The method is easy to implement and extremely efficient. A series of results for which comparisons are made with the known airfoils is presented.

  20. Learning Based Approach for Optimal Clustering of Distributed Program's Call Flow Graph

    NASA Astrophysics Data System (ADS)

    Abofathi, Yousef; Zarei, Bager; Parsa, Saeed

    Optimal clustering of call flow graph for reaching maximum concurrency in execution of distributable components is one of the NP-Complete problems. Learning automatas (LAs) are search tools which are used for solving many NP-Complete problems. In this paper a learning based algorithm is proposed to optimal clustering of call flow graph and appropriate distributing of programs in network level. The algorithm uses learning feature of LAs to search in state space. It has been shown that the speed of reaching to solution increases remarkably using LA in search process, and it also prevents algorithm from being trapped in local minimums. Experimental results show the superiority of proposed algorithm over others.

  1. Analysis and modeling of information flow and distributed expertise in space-related operations.

    PubMed

    Caldwell, Barrett S

    2005-01-01

    Evolving space operations requirements and mission planning for long-duration expeditions require detailed examinations and evaluations of information flow dynamics, knowledge-sharing processes, and information technology use in distributed expert networks. This paper describes the work conducted with flight controllers in the Mission Control Center (MCC) of NASA's Johnson Space Center. This MCC work describes the behavior of experts in a distributed supervisory coordination framework, which extends supervisory control/command and control models of human task performance. Findings from this work are helping to develop analysis techniques, information architectures, and system simulation capabilities for knowledge sharing in an expert community. These findings are being applied to improve knowledge-sharing processes applied to a research program in advanced life support for long-duration space flight. Additional simulation work is being developed to create interoperating modules of information flow and novice/expert behavior patterns. PMID:15835058

  2. Space power distribution system technology. Volume 3: Test facility design

    NASA Technical Reports Server (NTRS)

    Decker, D. K.; Cannady, M. D.; Cassinelli, J. E.; Farber, B. F.; Lurie, C.; Fleck, G. W.; Lepisto, J. W.; Messner, A.; Ritterman, P. F.

    1983-01-01

    The AMPS test facility is a major tool in the attainment of more economical space power. The ultimate goals of the test facility, its primary functional requirements and conceptual design, and the major equipment it contains are discussed.

  3. Effect of retransfusion after hemorrhagic hypotension on intrarenal distribution of blood flow in dogs

    PubMed Central

    Carriere, Serge; Daigneault, Bernard

    1970-01-01

    Hemorrhagic hypotension in anesthetized dogs produces a marked decrease of the cortical blood flow, whereas the medullary blood flow is well preserved. These animals were maintained at blood pressures of 50 mm Hg during a 3 hr period after which their blood pressures were restored by the reinfusion of blood or dextran, or both. In the first group of animals, the reinfusion of blood reestablished the blood pressure to control values, but the cortical blood flow was still nonuniformly decreased whereas the medullary blood flow appeared to be increased. In the second group of animals, phenoxybenzamine failed to protect the kidney completely since after blood reinfusion, the same anomalies described for the preceding group were found in 7 out of 10 dogs. The animals of the third group were reinfused with 50% of the shed blood and 10 ml/kg of a 10 g/100 ml solution of low molecular weight dextran. The modifications of the intrarenal distribution of the blood flow were less marked in this group although the blood flow rate of the inner cortex and the outer medulla was always elevated under these conditions. The reinfusion of low molecular weight dextran alone (20 ml/kg of a 10 g/100 ml solution) restored the blood pressure to levels slightly lower than those observed under control conditions but reestablished a normal pattern of intrarenal blood flow. The reinfusion of high molecular weight dextran was inefficient in correcting completely the anomalies of the renal blood flow. Mechanisms such as the increased sympathetic tone, the liberation of angiotensin, and the intravascular cellular aggregation could possibly account for the persisting anomalies of the renal circulation after reinfusion and are discussed. Images PMID:5480847

  4. Seismic monitoring of a flow test in the Salton Sea Geothermal Field

    SciTech Connect

    Jarpe, S.P.; Kasameyer, P.W.; Johnston, C.

    1989-06-01

    The purpose of this seismic monitoring project was to characterize in detail the micro-seismic activity related to the flow-injection test in the Salton Sea Geothermal Field. Our goal was to determine if any sources of seismic energy related to the test were observable at the surface, using both conventional seismic network techniques and relatively newer array techniques. These methods allowed us to detect and locate both impulsive microearthquakes and continuous sources of seismic energy. Our network, which was sensitive enough to be triggered by magnitude 0.0 or larger events, found no impulsive microearthquakes in the vicinity of the flow test in the 8 month period before the test and only one event during the flow test. We have observed some continuous seismic noise sources that may be attributed to the flow test. 4 refs., 4 figs.

  5. The distribution of lobate debris aprons and similar flows on Mars

    NASA Technical Reports Server (NTRS)

    Squyres, S. W.

    1979-01-01

    Planet-wide mapping of lobate debris aprons and other similar flows on Mars shows a strong concentration in two latitudinal bands roughly 25 deg wide and centered at 40 deg N and 45 deg S. This distribution supports the idea that these flows form when erosional debris is transported downslope and becomes mixed with ice deposited from the atmosphere, as these latitudes should receive high seasonal H2O frost deposition relative to the rest of the planet. Flows are found in the northern hemisphere band wherever old highland surfaces occur but are found in the southern hemisphere only near the two major impact basins, Argyre and Hellas. These areas are apparently characterized by mass wasting that is rapid relative to most of the southern hemisphere highlands. The rate of mass wasting may be related to the degree of consolidation of highland material.

  6. Distributed Parameter Analysis of Pressure and Flow Disturbances in Rocket Propellant Feed Systems

    NASA Technical Reports Server (NTRS)

    Dorsch, Robert G.; Wood, Don J.; Lightner, Charlene

    1966-01-01

    A digital distributed parameter model for computing the dynamic response of propellant feed systems is formulated. The analytical approach used is an application of the wave-plan method of analyzing unsteady flow. Nonlinear effects are included. The model takes into account locally high compliances at the pump inlet and at the injector dome region. Examples of the calculated transient and steady-state periodic responses of a simple hypothetical propellant feed system to several types of disturbances are presented. Included are flow disturbances originating from longitudinal structural motion, gimbaling, throttling, and combustion-chamber coupling. The analytical method can be employed for analyzing developmental hardware and offers a flexible tool for the calculation of unsteady flow in these systems.

  7. Pre-test CFD Calculations for a Bypass Flow Standard Problem

    SciTech Connect

    Rich Johnson

    2011-11-01

    The bypass flow in a prismatic high temperature gas-cooled reactor (HTGR) is the flow that occurs between adjacent graphite blocks. Gaps exist between blocks due to variances in their manufacture and installation and because of the expansion and shrinkage of the blocks from heating and irradiation. Although the temperature of fuel compacts and graphite is sensitive to the presence of bypass flow, there is great uncertainty in the level and effects of the bypass flow. The Next Generation Nuclear Plant (NGNP) program at the Idaho National Laboratory has undertaken to produce experimental data of isothermal bypass flow between three adjacent graphite blocks. These data are intended to provide validation for computational fluid dynamic (CFD) analyses of the bypass flow. Such validation data sets are called Standard Problems in the nuclear safety analysis field. Details of the experimental apparatus as well as several pre-test calculations of the bypass flow are provided. Pre-test calculations are useful in examining the nature of the flow and to see if there are any problems associated with the flow and its measurement. The apparatus is designed to be able to provide three different gap widths in the vertical direction (the direction of the normal coolant flow) and two gap widths in the horizontal direction. It is expected that the vertical bypass flow will range from laminar to transitional to turbulent flow for the different gap widths that will be available.

  8. Field test of a biological assumption of instream flow models

    SciTech Connect

    Cada, G.F.; Sale, M.J.; Cushman, R.M.; Loar, J.M.

    1983-01-01

    Hydraulic-rating methods are an attractive means of deriving instream flow recommendations at many small hydropower sites because they represent a compromise between relatively inexpensive, low-resolution, discharge methods and the costly, complex, habitat evaluation models. Like the other methods, however, they rely on certain biological assumptions about the relationship between aquatic biota and streamflow characteristics. One such assumption is that benthic production available as food for fishes is proportional to stream bottom area. Wetted perimeter is an easily measured physical parameter which represents bottom area and that is a function of discharge. Therefore, wetted perimeter should reflect the benthic food resource available to support stream fishes under varying flows. As part of a larger effort to compare a number of existing instream flow assessment methods in southern Appalachian trout streams, we examined the validity of the benthos/wetted perimeter relationship at four field sites. Benthos samples were taken at permanent riffle transects over a variety of discharges and were used to relate observed benthos densities to the fluctuations in wetted perimeter and streamflow in these systems. For most of the sites and taxa examined, benthic densities did not show a consistent relationship with discharge/wetted perimeter dynamics. Our analysis indicates that simple physical habitat descriptors obtained from hydraulic-rating models do not provide sufficient information on the response of benthic organisms to decreased discharges. Consequently, these methods may not be sufficient to protect aquatic resources in water-use conflicts.

  9. Numerical Calibration of Mass Flow Plug for Inlet Testing

    NASA Technical Reports Server (NTRS)

    Sasson, Jonathan; Barnhart, Paul; Davis, David O.

    2015-01-01

    A simple control volume model has been developed to calculate the discharge coefficient through a mass flow plug (MFP) and validated with a calibration experiment. The maximum error of the model within the operating region of the MFP is 0.54%. The control volume analysis developed work is comprised of a sequence of flow calculations through the MFP. The model uses the MFP geometry and operating pressure and temperature to couple continuity, momentum, energy, an equation of state, and wall shear. The discharge coefficient calculation also includes the effects of boundary layer growth, including the reduction in cross-sectional flow area as characterized by the boundary layer displacement thickness. The last calculation in the sequence uses an integral method to calculate the growth of the boundary layer, from which the displacement thickness is then determined. The result of these successive calculations is an accurate one-dimension model of the velocity, pressure, and temperature through the MFP. For comparison, a computational fluid dynamic (CFD) calibration is shown, which when compared to the presented numerical model, had a lower accuracy with a maximum error of 1.35% in addition to being slower by a factor of 100."

  10. Resin flow monitoring in vacuum-assisted resin transfer molding using optical fiber distributed sensor

    NASA Astrophysics Data System (ADS)

    Eum, Soohyun; Kageyama, Kazuro; Murayama, Hideaki; Ohsawa, Isamu; Uzawa, Kiyoshi; Kanai, Makoto; Igawa, Hirotaka

    2007-04-01

    In this study, we implemented resin flow monitoring by using an optical fiber sensor during vacuum assisted resin transfer molding (VaRTM).We employed optical frequency domain reflectometry (OFDR) and fiber Bragg grating (FBG) sensor for distributed sensing. Especially, long gauge FBGs (about 100mm) which are 10 times longer than an ordinary FBG were employed for more effective distributed sensing. A long gauge FBG was embedded in GFRP laminates, and other two ones were located out of laminate for wavelength reference and temperature compensation, respectively. During VaRTM, the embedded FBG could measure how the preform affected the sensor with vacuum pressure and resin was flowed into the preform. In this study, we intended to detect the gradient of compressive strain between impregnated part and umimpregnated one within long gauge FBG. If resin is infused to preform, compressive strain which is generated on FBG is released by volume of resin. We could get the wavelength shift due to the change of compressive strain along gauge length of FBG by using short-time Fourier transformation for signal acquired from FBG. Therefore, we could know the resin flow front with the gradient of compressive strain of FBG. In this study, we used silicon oil which has same viscosity with resin substitute for resin in order to reuse FBG. In order to monitor resin flow, the silicon oil was infused from one edge of preform, the silicon oil was flowed from right to left. Then, we made dry spot within gauge length by infusing silicon oil to both sides of preform to prove the ability of dry spot monitoring with FBG. We could monitor resin flow condition and dry spot formation successfully using by FBG based on OFDR.

  11. Rayleigh Scattering for Measuring Flow in a Nozzle Testing Facility

    NASA Technical Reports Server (NTRS)

    Gomez, Carlos R.; Panda, Jayanta

    2006-01-01

    A molecular Rayleigh-scattering-based air-density measurement system was built in a large nozzle-and-engine-component test facility for surveying supersonic plumes from jet-engine exhaust. A molecular Rayleigh-scattering-based air-density measurement system was built in a large nozzle-and-enginecomponent test facility for surveying supersonic plumes from jet-engine exhaust

  12. Two-Phase Refrigerant Flow Distribution in a Multipass Evaporator with Vertical Upward Main Tube

    NASA Astrophysics Data System (ADS)

    Watanabe, Manabu; Katasuta, Masafumi

    In this article, a calculation model that enables to predict two-phaseflow distribution in a multipass evaporator is proposed. The model considers the multipass evaporator as the combination of simple elements, i. e. straight pipes and T-junctions, and utilizes the correlations to predict the pressure drop at the elements. For the T-junction, however, we have so little knowledge, especially for the small diameter T-junction, that we make some experiments to evaluate the existing correlations for the junction pressure drop. We also do not have reliable model for predicting the phase separation characteristics, so that we used the empirical equations for liquid division ratio derived in our previous papers. By this model, gas phase flow distribution to each pass is determined as it makes the pressure at the outlet of each pass equal. Calculation results well predict the previously presented experimental data that were obtained under the condition of larger quality at the header inlet. The suitableness of this model suggests that the complexity of the two-phase flow distribution in multipass tube attributes to the phase separation phenomena in dividing two-phase flow at a T-junction

  13. Common patterns of energy flow and biomass distribution on weighted food webs

    NASA Astrophysics Data System (ADS)

    Zhang, Jiang; Feng, Yuanjing

    2014-07-01

    Weights of edges and nodes on food webs which are available from the empirical data hide much information about energy flows and biomass distributions in ecosystem. We define a set of variables related to weights for each species i, including the throughflow Ti, the total biomass Xi, and the dissipated flow Di (output to the environment) to uncover the following common patterns in 19 empirical weighted food webs: (1) DGBD distributions (Discrete version of a Generalized Beta Distribution), a kind of deformed Zipf's law, of energy flow and storage biomass; (2) The allometric scaling law Ti∝Xiα, which can be viewed as the counterpart of the Kleiber's 3/4 law at the population level; (3) The dissipation law Di∝Tiβ; and (4) The gravity law, including univariate version f∝( and bivariate approvement f∝Tiγ1Tjγ2. These patterns are very common and significant in all collected webs, as a result, some remarkable regularities are hidden in weights.

  14. Validation of non-Darcian flow effects in slug tests conducted in fractured rock boreholes

    NASA Astrophysics Data System (ADS)

    Quinn, Patryk M.; Parker, Beth L.; Cherry, John A.

    2013-04-01

    SummaryA series of rising and falling head slug tests with different initial applied head differentials (ΔHo) were conducted in open fractured dolostone and sandstone boreholes using straddle packers isolating specific depth intervals (1.5 m length) to examine the influence of non-Darcian flow. The open holes were developed and inspected using video and acoustic televiewing (ATV) to ensure that evidence of skin effects due to drilling were absent. The transmissivity (T) values obtained from both the rising and falling head slug tests were very similar at low initial applied head; however, the T values were progressively smaller at larger ΔHo, suggesting error due to non-Darcian flow. Non-Darcian flow behavior was confirmed by constant head step tests conducted in the same test intervals where the injection rate (Q) vs. applied head (dH) relationship became non-linear at relatively low injection rates, and the non-Darcian data also resulted in lower T values. For a series of slug tests conducted at different ΔHo, non-Darcian flow effects gradually increased as ΔHo increased, consistent with the trends for constant head step tests conducted in the same test intervals. To maintain Darcian flow conditions in the fractured dolostone and sandstone tested in this study, ΔHo must be kept small, generally less than 0.2 m. This study demonstrates that by conducting both "stepped" slug tests and constant head step tests, the Darcian flow assumption for both types of tests can be rigorously validated. However, when only slug tests are conducted, it is necessary to conduct a series of "stepped" slug tests, including tests with small applied head differentials, to avoid errors due to non-Darcian flow.

  15. Design of Material Strength Test in Lead-Bismuth Flow

    SciTech Connect

    Masatoshi Kondo; Minoru Takahashi; Koji Hata

    2002-07-01

    Liquid lead and lead-bismuth have drawn the attention as one of the candidate coolants of the fast breeder reactors (FBRs), and the accelerator driven transmutation systems (ADSs). In order to use the coolant to the systems, the physical and chemical characteristics of the heavy metals are necessary. This plan has been proposed for the strength test of materials in the liquid metal surroundings. The lead-bismuth circulation loop with the strength test has been designed, and the strength test of candidate materials has been planned. (authors)

  16. Velocity and void distribution in a counter-current two-phase flow

    SciTech Connect

    Gabriel, S.; Schulenberg, T.; Laurien, E.

    2012-07-01

    Different flow regimes were investigated in a horizontal channel. Simulating a hot leg injection in case of a loss of coolant accident or flow conditions in reflux condenser mode, the hydraulic jump and partially reversed flow were identified as major constraints for a high amount of entrained water. Trying to simulate the reflux condenser mode, the test section now includes an inclined section connected to a horizontal channel. The channel is 90 mm high and 110 mm wide. Tests were carried out for water and air at ambient pressure and temperature. High speed video-metry was applied to obtain velocities from flow pattern maps of the rising and falling fluid. In the horizontal part of the channel with partially reversed flow the fluid velocities were measured by planar particle image velocimetry. To obtain reliable results for the gaseous phase, this analysis was extended by endoscope measurements. Additionally, a new method based on the optical refraction at the interface between air and water in a back-light was used to obtain time-averaged void fraction. (authors)

  17. Development of Flow Boiling and Condensation Experiment on the International Space Station- Normal and Low Gravity Flow Boiling Experiment Development and Test Results

    NASA Technical Reports Server (NTRS)

    Nahra, Henry K.; Hall, Nancy R.; Hasan, Mohammad M.; Wagner, James D.; May, Rochelle L.; Mackey, Jeffrey R.; Kolacz, John S.; Butcher, Robert L.; Frankenfield, Bruce J.; Mudawar, Issam; Konichi, Chris; Hyounsoon, Lee

    2013-01-01

    Flow boiling and condensation have been identified as two key mechanisms for heat transport that are vital for achieving weight and volume reduction as well as performance enhancement in future space systems. Since inertia driven flows are demanding on power usage, lower flows are desirable. However, in microgravity, lower flows are dominated by forces other than inertia (like the capillary force). It is of paramount interest to investigate limits of low flows beyond which the flow is inertial enough to be gravity independent. One of the objectives of the Flow Boiling and Condensation Flight Experiment sets to investigate these limits for flow boiling and condensation. A two-phase flow loop consisting of a Flow Boiling Module and two Condensation Modules has been developed to experimentally study flow boiling condensation heat transfer in the reduced gravity environment provided by the reduced gravity platform. This effort supports the development of a flow boiling and condensation facility for the International Space Station (ISS). The closed loop test facility is designed to deliver the test fluid, FC-72 to the inlet of any one of the test modules at specified thermodynamic and flow conditions. The zero-g-aircraft tests will provide subcooled and saturated flow boiling critical heat flux and flow condensation heat transfer data over wide range of flow velocities. Additionally, these tests will verify the performance of all gravity sensitive components, such as evaporator, condenser and accumulator associated with the two-phase flow loop. We will present in this paper the breadboard development and testing results which consist of detailed performance evaluation of the heater and condenser combination in reduced and normal gravity. We will also present the design of the reduced gravity aircraft rack and the results of the ground flow boiling heat transfer testing performed with the Flow Boiling Module that is designed to investigate flow boiling heat transfer and

  18. Comparison of wind tunnel test results at free stream Mach 0.7 with results from the Boeing TEA-230 subsonic flow method. [wing flow method tests

    NASA Technical Reports Server (NTRS)

    Mohn, L. W.

    1975-01-01

    The use of the Boeing TEA-230 Subsonic Flow Analysis method as a primary design tool in the development of cruise overwing nacelle configurations is presented. Surface pressure characteristics at 0.7 Mach number were determined by the TEA-230 method for a selected overwing flow-through nacelle configuration. Results of this analysis show excellent overall agreement with corresponding wind tunnel data. Effects of the presence of the nacelle on the wing pressure field were predicted accurately by the theoretical method. Evidence is provided that differences between theoretical and experimental pressure distributions in the present study would not result in significant discrepancies in the nacelle lines or nacelle drag estimates.

  19. Quantifying Distribution of Flow Cytometric TCR-Vβ Usage with Economic Statistics

    PubMed Central

    van der Geest, Kornelis S. M.; Abdulahad, Wayel H.; Horst, Gerda; Lorencetti, Pedro G.; Bijzet, Johan; Arends, Suzanne; van der Heiden, Marieke; Buisman, Anne-Marie; Kroesen, Bart-Jan; Brouwer, Elisabeth; Boots, Annemieke M. H.

    2015-01-01

    Measuring changes of the T cell receptor (TCR) repertoire is important to many fields of medicine. Flow cytometry is a popular technique to study the TCR repertoire, as it quickly provides insight into the TCR-Vβ usage among well-defined populations of T cells. However, the interpretation of the flow cytometric data remains difficult, and subtle TCR repertoire changes may go undetected. Here, we introduce a novel means for analyzing the flow cytometric data on TCR-Vβ usage. By applying economic statistics, we calculated the Gini-TCR skewing index from the flow cytometric TCR-Vβ analysis. The Gini-TCR skewing index, which is a direct measure of TCR-Vβ distribution among T cells, allowed us to track subtle changes of the TCR repertoire among distinct populations of T cells. Application of the Gini-TCR skewing index to the flow cytometric TCR-Vβ analysis will greatly help to gain better understanding of the TCR repertoire in health and disease. PMID:25923356

  20. Analysis Of Residence Time Distribution Of Fluid Flow By Axial Dispersion Model

    SciTech Connect

    Sugiharto; Su'ud, Zaki; Kurniadi, Rizal; Waris, Abdul; Abidin, Zainal

    2010-12-23

    Radioactive tracer {sup 82}Br in the form of KBr-82 with activity {+-} 1 mCi has been injected into steel pipeline to qualify the extent dispersion of water flowing inside it. Internal diameter of the pipe is 3 in. The water source was originated from water tank through which the water flow gravitically into the pipeline. Two collimated sodium iodide detectors were used in this experiment each of which was placed on the top of the pipeline at the distance of 8 and 11 m from injection point respectively. Residence time distribution (RTD) curves obtained from injection of tracer are elaborated numerically to find information of the fluid flow properties. The transit time of tracer calculated from the mean residence time (MRT) of each RTD curves is 14.9 s, therefore the flow velocity of the water is 0.2 m/s. The dispersion number, D/uL, for each RTD curve estimated by using axial dispersion model are 0.055 and 0.06 respectively. These calculations are performed after fitting the simulated axial dispersion model on the experiment curves. These results indicated that the extent of dispersion of water flowing in the pipeline is in the category of intermediate.

  1. Investigation of liquid phase axial dispersion in Taylor bubble flow by radiotracer residence time distribution analysis

    NASA Astrophysics Data System (ADS)

    Chughtai, I. R.; Iqbal, W.; Din, G. U.; Mehdi, S.; Khan, I. H.; Inayat, M. H.; Jin, J. H.

    2013-05-01

    A gas-liquid Taylor bubble flow occurs in small diameter channels in which gas bubbles are separated by slugs of pure liquid. This type of flow regime is well suited for solid catalyzed gas-liquid reactors in which the reaction efficiency is a strong function of axial dispersion in the regions of pure liquid. This paper presents an experimental study of liquid phase axial dispersion in a Taylor bubble flow developed in a horizontal tube using high speed photography and radiotracer residence time distribution (RTD) analysis. A parametric dependence of axial dispersion on average volume fraction of gas phase was also investigated by varying the relative volumetric flow rates of the two phases. 137mBa produced from a 137Cs/137mBa radionuclide generator was used as radiotracer and measurements were made using the NaI(Tl) scintillation detectors. Validation of 137mBa in the form of barium chloride as aqueous phase radiotracer was also carried out. Axial Dispersion Model (ADM) was used to simulate the hydrodynamics of the system and the results of the experiment are presented. It was observed that the system is characterized by very high values of Peclet Number (Pe˜102) which reveals an approaching plug type flow. The experimental and model estimated values of mean residence times were observed in agreement with each other.

  2. Analysis Of Residence Time Distribution Of Fluid Flow By Axial Dispersion Model

    NASA Astrophysics Data System (ADS)

    Sugiharto, Su'ud, Zaki; Kurniadi, Rizal; Waris, Abdul; Abidin, Zainal

    2010-12-01

    Radioactive tracer 82Br in the form of KBr-82 with activity ± 1 mCi has been injected into steel pipeline to qualify the extent dispersion of water flowing inside it. Internal diameter of the pipe is 3 in. The water source was originated from water tank through which the water flow gravitically into the pipeline. Two collimated sodium iodide detectors were used in this experiment each of which was placed on the top of the pipeline at the distance of 8 and 11 m from injection point respectively. Residence time distribution (RTD) curves obtained from injection of tracer are elaborated numerically to find information of the fluid flow properties. The transit time of tracer calculated from the mean residence time (MRT) of each RTD curves is 14.9 s, therefore the flow velocity of the water is 0.2 m/s. The dispersion number, D/uL, for each RTD curve estimated by using axial dispersion model are 0.055 and 0.06 respectively. These calculations are performed after fitting the simulated axial dispersion model on the experiment curves. These results indicated that the extent of dispersion of water flowing in the pipeline is in the category of intermediate.

  3. An evaluation of pressure and flow measurement in the Molten Salt Test Loop (MSTL) system.

    SciTech Connect

    Gill, David Dennis; Kolb, William J.; Briggs, Ronald J.

    2013-07-01

    The National Solar Thermal Test Facility at Sandia National Laboratories has a unique test capability called the Molten Salt Test Loop (MSTL) system. MSTL allows customers and researchers to test components in flowing, molten nitrate salt at plant-like conditions for pressure, flow, and temperature. An important need in thermal storage systems that utilize molten salts is for accurate flow and pressure measurement at temperatures above 535%C2%B0C. Currently available flow and pressure instrumentation for molten salt is limited to 535%C2%B0C and even at this temperature the pressure measurement appears to have significant variability. It is the design practice in current Concentrating Solar Power plants to measure flow and pressure on the cold side of the process or in dead-legs where the salt can cool, but this practice won't be possible for high temperature salt systems. For this effort, a set of tests was conducted to evaluate the use of the pressure sensors for flow measurement across a device of known flow coefficient Cv. To perform this task, the pressure sensors performance was evaluated and was found to be lacking. The pressure indicators are severely affected by ambient conditions and were indicating pressure changes of nearly 200psi when there was no flow or pressure in the system. Several iterations of performance improvement were undertaken and the pressure changes were reduced to less than 15psi. The results of these pressure improvements were then tested for use as flow measurement. It was found that even with improved pressure sensors, this is not a reliable method of flow measurement. The need for improved flow and pressure measurement at high temperatures remains and will need to be solved before it will be possible to move to high temperature thermal storage systems with molten salts.

  4. Fluctuating Pressure Data from 2-D Nozzle Cold Flow Tests (Dual Bell)

    NASA Technical Reports Server (NTRS)

    Nesman, Tomas E.

    2001-01-01

    Rocket engines nozzle performance changes as a vehicle climbs through the atmosphere. An altitude compensating nozzle, ACN, is intended to improve on a fixed geometry bell nozzle that performs at optimum at only one trajectory point. In addition to nozzle performance, nozzle transient loads are an important consideration. Any nozzle experiences large transient toads when shocks pass through the nozzle at start and shutdown. Additional transient toads will occur at transitional flow conditions. The objectives of cold flow nozzle testing at MSFC are CFD benchmark / calibration and Unsteady flow / sideloads. Initial testing performed with 2-D inserts to 14" transonic wind tunnel. Recent review of 2-D data in preparation for nozzle test facility 3-D testing. This presentation shows fluctuating pressure data and some observations from 2-D dual-bell nozzle cold flow tests.

  5. Closed form flow model of a damped slug test in a fractured bedrock borehole

    NASA Astrophysics Data System (ADS)

    Ostendorf, David W.; Lukas, William G.; Hinlein, Erich S.

    2015-10-01

    An existing closed form model is modified to describe the damped response of groundwater in a fractured bedrock borehole with variable apertures and dips to a slug test. The existing theory, which requires single sized horizontal fractures, is accurately calibrated by slug test data from three uncased bedrock boreholes in the Dedham Granite and an observation well screened just below the contact surface with a till drumlin. Apertures and dips vary however, so the ability of the modified theory to accommodate different sizes and inclinations improves upon the physical validity of its predecessor when fracture information accompanies slug test data. Geophysical logs identify a large number and dip of fractures in the uncased boreholes in the Dedham Granite in this regard. A lognormally distributed, horizontal aperture calibration of the slug tests in the uncased boreholes retains the accuracy of the single size model, and yields aperture statistics more consistent with literature values. The slug test in the screened observation well is accurately calibrated with the modified horizontal theory for discrete (two) sizes, based upon the average fracture spacing found in the uncased boreholes. All four results yield comparable compressibility estimates, which depend on fracture spacing but not size or dip. The calibrated aperture size and calculated fracture porosity and permeability decrease with length of the borehole into the Dedham Granite. The measured dip and aperture for flowing and nonflowing fractures in one of the boreholes accurately calibrates the modified theory. The inclusion of dip reduces the calibrated permeability because of the increased ellipsoidal area at the interface of the borehole and the inclined fractures.

  6. Biodegradation of oxo-alcohol ethoxylates in the continuous flow activated sludge simulation test.

    PubMed

    Szymanski, Andrzej; Wyrwas, Bogdan; Bubien, Ewa; Kurosz, Tatiana; Hreczuch, Wieslaw; Zembrzuski, Wlodzimierz; Lukaszewski, Zenon

    2002-07-01

    Biodegradation of two alpha-methyl branched oxo-alcohol ethoxylates (OAE) of different polydispersity: LIAL 125/14 BRD (LIALB) (broad M.W. distribution) and LIAL 125/14 NRD (LIALN) (narrow M.W. distribution), both having an average of 14 oxyethylene subunits (EO) and a C(12-15) alkyl moiety were tested under the continuous flow activated sludge conditions of the classical Husmann plant. Primary biodegradation and concentration of metabolites: free oxo-alcohol fraction (FOA) and poly(ethylene glycols) (PEG), were measured. PEG were divided into two fractions: short-chained PEG (PEGshch) (1-4 EO) and long-chained PEG (PEGlch) (>4 EO). The indirect tensammetric technique combined with an adequate separation was used for analysis. Central fission was found to be a highly dominating pathway, as is the case with fatty alcohol ethoxylates. OAE are highly primarily biodegraded (above 95%). High concentrations of FOA and PEG are formed. Once formed the PEGlch are further fragmented into the PEGshch. Free alcohol fraction compounds are biodegraded sooner when alkyl moiety is shorter. OAE polydispersity has an influence on the kinetics of biodegradation; PEG formed from LIALN are biodegraded slower and to a lower degree than those from LIALB. PMID:12188138

  7. Using borehole geophysics and cross-borehole flow testing to define hydraulic connections between fracture zones in bedrock aquifers

    USGS Publications Warehouse

    Paillet, Frederick L.

    1993-01-01

    Nearly a decade of intensive geophysical logging at fractured rock hydrology research sites indicates that geophysical logs can be used to identify and characterize fractures intersecting boreholes. However, borehole-to-borehole flow tests indicate that only a few of the apparently open fractures found to intersect boreholes conduct flow under test conditions. This paper presents a systematic approach to fracture characterization designed to define the distribution of fractures along boreholes, relate the measured fracture distribution to structure and lithology of the rock mass, and define the nature of fracture flow paths across borehole arrays. Conventional electrical resistivity, gamma, and caliper logs are used to define lithology and large-scale structure. Borehole wall image logs obtained with the borehole televiewer are used to give the depth, orientation, and relative size of fractures in situ. High-resolution flowmeter measurements are used to identify fractures conducting flow in the rock mass adjacent to the boreholes. Changes in the flow field over time are used to characterize the hydraulic properties of fracture intersections between boreholes. Application of this approach to an array of 13 boreholes at the Mirror Lake, New Hamsphire site demonstrates that the transient flow analysis can be used to distinguish between fractures communicating with each other between observation boreholes, and those that are hydraulically isolated from each other in the surrounding rock mass. The Mirror Lake results also demonstrate that the method is sensitive to the effects of boreholes on the hydraulic properties of the fractured-rock aquifer. Experiments conducted before and after the drilling of additional boreholes in the array and before and after installation of packers in existing boreholes demonstrate that the presence of new boreholes or the inflation of packers in existing boreholes has a large effect on the measured hydraulic properties of the rock mass

  8. Field testing the hypothesis of Darcian flow through a carbonate aquifer.

    USGS Publications Warehouse

    Hickey, J.J.

    1984-01-01

    The acceptability of the hypothesis of Darcian flow through a semiconfined carbonate aquifer was tested prior to running a multiple-day aquifer test in Pinellas County, Florida. The approach used to test the hypothesis was to run a number of hour-long aquifer tests at different discharges with drawdown measured at the same time during each test in two observation wells, one at 35 feet and the other at 733 feet from the pumped well. The hypothesis of Darcian flow through the semiconfined carbonate aquifer was deemed acceptable.-from Author

  9. Multiphase flow modeling of a crude-oil spill site with a bimodal permeability distribution

    USGS Publications Warehouse

    Dillard, L.A.; Essaid, H.I.; Herkelrath, W.N.

    1997-01-01

    Fluid saturation, particle-size distribution, and porosity measurements were obtained from 269 core samples collected from six boreholes along a 90-m transect at a subregion of a crude-oil spill site, the north pool, near Bemidji, Minnesota. The oil saturation data, collected 11 years after the spill, showed an irregularly shaped oil body that appeared to be affected by sediment spatial variability. The particle-size distribution data were used to estimate the permeability (k) and retention curves for each sample. An additional 344 k estimates were obtained from samples previously collected at the north pool. The 613 k estimates were distributed bimodal log normally with the two population distributions corresponding to the two predominant lithologies: a coarse glacial outwash deposit and fine-grained interbedded lenses. A two-step geostatistical approach was used to generate a conditioned realization of k representing the bimodal heterogeneity. A cross-sectional multiphase flow model was used to simulate the flow of oil and water in the presence of air along the north pool transect for an 11-year period. The inclusion of a representation of the bimodal aquifer heterogeneity was crucial for reproduction of general features of the observed oil body. If the bimodal heterogeneity was characterized, hysteresis did not have to be incorporated into the model because a hysteretic effect was produced by the sediment spatial variability. By revising the relative permeability functional relation, an improved reproduction of the observed oil saturation distribution was achieved. The inclusion of water table fluctuations in the model did not significantly affect the simulated oil saturation distribution.

  10. Design and Implementation of a Characterization Test Rig for Evaluating High Bandwidth Liquid Fuel Flow Modulators

    NASA Technical Reports Server (NTRS)

    Saus, Joseph R.; Chang, Clarence T.; DeLaat, John C.; Vrnak, Daniel R.

    2010-01-01

    A test rig was designed and developed at the NASA Glenn Research Center (GRC) for the purpose of characterizing high bandwidth liquid fuel flow modulator candidates to determine their suitability for combustion instability control research. The test rig is capable of testing flow modulators at up to 600 psia supply pressure and flows of up to 2 gpm. The rig is designed to provide a quiescent flow into the test section in order to isolate the dynamic flow modulations produced by the test article. Both the fuel injector orifice downstream of the test article and the combustor are emulated. The effect of fuel delivery line lengths on modulator dynamic performance can be observed and modified to replicate actual fuel delivery systems. For simplicity, water is currently used as the working fluid, although future plans are to use jet fuel. The rig is instrumented for dynamic pressures and flows and a high-speed data system is used for dynamic data acquisition. Preliminary results have been obtained for one candidate flow modulator.

  11. Sample Size Tables, "t" Test, and a Prevalent Psychometric Distribution.

    ERIC Educational Resources Information Center

    Sawilowsky, Shlomo S.; Hillman, Stephen B.

    Psychology studies often have low statistical power. Sample size tables, as given by J. Cohen (1988), may be used to increase power, but they are based on Monte Carlo studies of relatively "tame" mathematical distributions, as compared to psychology data sets. In this study, Monte Carlo methods were used to investigate Type I and Type II error…

  12. A Distribution-Free Test for Model Comparisons.

    ERIC Educational Resources Information Center

    Keats, John B.; Brewer, James K.

    This paper presents an index of goodness-of-fit for comparing m models over n trials. The index allows for differentiated weighting of the trials as to their importance in the comparison of the models. Several possible weighting schemes are suggested and the conditions on the weights which assure asymptotic normality of the index distribution are…

  13. Phase 2: HGM air flow tests in support of HEX vane investigation

    NASA Technical Reports Server (NTRS)

    Cox, G. B., Jr.; Steele, L. L.; Eisenhart, D. W.

    1993-01-01

    Following the start of SSME certification testing for the Pratt and Whitney Alternate Turbopump Development (ATD) High Pressure Oxidizer Turbopump (HPOTP), cracking of the leading edge of the inner HEX vane was experienced. The HEX vane, at the inlet of the oxidizer bowl in the Hot Gas Manifold (HGM), accepts the HPOTP turbine discharge flow and turns it toward the Gaseous Oxidizer Heat Exchanger (GOX HEX) coil. The cracking consistently initiated over a specific circumferential region of the hex vane, with other circumferential locations appearing with increased run time. Since cracking had not to date been seen with the baseline HPOTP, a fluid-structural interaction involving the ATD HPOTP turbine exit flowfield and the HEX inner vane was suspected. As part of NASA contract NAS8-36801, Pratt and Whitney conducted air flow tests of the ATD HPOTP turbine turnaround duct flowpath in the MSFC Phase 2 HGM air flow model. These tests included HEX vane strain gages and additional fluctuating pressure gages in the turnaround duct and HEX vane flowpath area. Three-dimensional flow probe measurements at two stations downstream of the turbine simulator exit plane were also made. Modifications to the HPOTP turbine simulator investigated the effects on turbine exit flow profile and velocity components, with the objective of reproducing flow conditions calculated for the actual ATD HPOTP hardware. Testing was done at the MSFC SSME Dynamic Fluid Air Flow (Dual-Leg) Facility, at air supply pressures between 50 and 250 psia. Combinations of turbine exit Mach number and pressure level were run to investigate the effect of flow regime. Information presented includes: (1) Descriptions of turbine simulator modifications to produce the desired flow environment; (2) Types and locations for instrumentation added to the flow model for improved diagnostic capability; (3) Evaluation of the effect of changes to the turbine simulator flowpath on the turbine exit flow environment; and (4

  14. Effects of shaft supporting structure on performance test of axial flow fan

    NASA Astrophysics Data System (ADS)

    Ma, R.; Liu, S. L.; Li, M. X.; Zheng, S. Y.

    2016-05-01

    CFD numerical simulation combined with theoretical analysis are used to research and discuss the obstructing effect, caused by the supporting structure of torsion meter and connecting shaft, on the outlet airflow of axial-flow fan in type-C ducted inlet device. The relations between axial flow fan's total pressure efficiency and flow rate are studied when the distance between supporting structure and outlet section is different, which may provide a reference for the proper design of the performance test device.

  15. Phase 2: HGM air flow tests in support of HEX vane investigation

    NASA Astrophysics Data System (ADS)

    Cox, G. B., Jr.; Steele, L. L.; Eisenhart, D. W.

    1993-07-01

    Following the start of SSME certification testing for the Pratt and Whitney Alternate Turbopump Development (ATD) High Pressure Oxidizer Turbopump (HPOTP), cracking of the leading edge of the inner HEX vane was experienced. The HEX vane, at the inlet of the oxidizer bowl in the Hot Gas Manifold (HGM), accepts the HPOTP turbine discharge flow and turns it toward the Gaseous Oxidizer Heat Exchanger (GOX HEX) coil. The cracking consistently initiated over a specific circumferential region of the hex vane, with other circumferential locations appearing with increased run time. Since cracking had not to date been seen with the baseline HPOTP, a fluid-structural interaction involving the ATD HPOTP turbine exit flowfield and the HEX inner vane was suspected. As part of NASA contract NAS8-36801, Pratt and Whitney conducted air flow tests of the ATD HPOTP turbine turnaround duct flowpath in the MSFC Phase 2 HGM air flow model. These tests included HEX vane strain gages and additional fluctuating pressure gages in the turnaround duct and HEX vane flowpath area. Three-dimensional flow probe measurements at two stations downstream of the turbine simulator exit plane were also made. Modifications to the HPOTP turbine simulator investigated the effects on turbine exit flow profile and velocity components, with the objective of reproducing flow conditions calculated for the actual ATD HPOTP hardware. Testing was done at the MSFC SSME Dynamic Fluid Air Flow (Dual-Leg) Facility, at air supply pressures between 50 and 250 psia. Combinations of turbine exit Mach number and pressure level were run to investigate the effect of flow regime. Information presented includes: (1) Descriptions of turbine simulator modifications to produce the desired flow environment; (2) Types and locations for instrumentation added to the flow model for improved diagnostic capability; (3) Evaluation of the effect of changes to the turbine simulator flowpath on the turbine exit flow environment; and (4

  16. Altitude Investigation of Gas Temperature Distribution at Turbine of Three Similar Axial-Flow Turbojet Engines

    NASA Technical Reports Server (NTRS)

    Prince, W.R.; Schulze, F.W.

    1952-01-01

    An investigation of the effect of inlet pressure, corrected engine speed, and turbine temperature level on turbine-inlet gas temperature distributions was conducted on a J40-WE-6, interim J40-WE-6, and prototype J40-WE-8 turbojet engine in the altitude wind tunnel at the NAC.4 Lewis laboratory. The engines were investigated over a range of simulated pressure altitudes from 15,000 to 55,000 feet, flight Mach numbers from 0.12 to 0.64, and corrected engine speeds from 7198 to 8026 rpm, The gas temperature distribution at the turbine of the three engines over the range of operating conditions investigated was considered satisfactory from the standpoint of desired temperature distribution with one exception - the distribution for the J40-WE-6 engine indicated a trend with decreasing engine-inlet pressure for the temperature to exceed the desired in the region of the blade hub. Installation of a compressor-outlet mixer vane assembly remedied this undesirable temperature distribution, The experimental data have shown that turbine-inlet temperature distributions are influenced in the expected manner by changes in compressor-outlet pressure or mass-flow distribution and by changes in combustor hole-area distribution. The similarity between turbine-inlet and turbine-outlet temperature distribution indicated only a small shift in temperature distribution imposed by the turbine rotors. The attainable jet thrusts of the three engines were influenced in different degrees and directions by changes in temperature distributions with change in engine-inlet pressure. Inability to match the desired temperature distribution resulted, for the J40-WE-6 engine, in an 11-percent thrust loss based on an average turbine-inlet temperature of 1500 F at an engine-inlet pressure of 500 pounds per square foot absolute. Departure from the desired temperature distribution in the Slade tip region results, for the prototype J40-WE-8 engine, in an attainable thrust increase of 3 to 4 percent as

  17. Cerebral blood flow response pattern during balloon test occlusion of the internal carotid artery

    SciTech Connect

    Witt, J.P.; Yonas, H.; Jungreis, C.

    1994-05-01

    To evaluate the risk of temporary or permanent internal carotid artery occlusion. In 156 patients intraarterial balloon test occlusion in combination with a stable xenon-enhanced CT cerebral blood flow study was performed before radiologic or surgical treatment. All 156 patients passed the clinical balloon test occlusion and underwent a xenon study in combination with a second balloon test. Quantitative flow data were analyzed for absolute changes as well as changes in symmetry. Fourteen patients exhibited reduced flow values between 20 and 30 mL/100 g per minute, an absolute decrease in flow, and significant asymmetry in the middle cerebral artery territory during balloon test occlusion. These patients would be considered at high risk for cerebral infarction if internal carotid artery occlusion were to be performed. With one exception they belonged to a group (class I) of 61 patients who showed bilateral or ipsilateral flow decrease and significant asymmetry with lower flow on the side of occlusion. The other 95 patients, who showed a variety of cerebral blood flow response patterns including ipsilateral or bilateral flow increase, were at moderate (class II) or low (class III) stroke risk. In contrast to these findings, exclusively qualitative flow analysis failed to identify the patients at high risk: a threshold with an asymmetry index of 10% revealed only 16% specificity whereas an asymmetry index of 45% showed only 61% sensitivity for detection of low flow areas (<30 mL/100 g per minute). For achieving a minimal hemodynamic related-stroke rate associated with permanent clinical internal carotid artery occlusion we suggest integration of a thorough analysis of quantitative cerebral blood flow data before and during balloon test occlusion. 68 refs., 5 figs., 2 tabs.

  18. Development of an example flow test object and comparison of five of these test objects, constructed in various laboratories.

    PubMed

    Teirlinck, C J; Bezemer, R A; Kollmann, C; Lubbers, J; Hoskins, P R; Ramnarine, K V; Fish, P; Fredeldt, K E; Schaarschmidt, U G

    1998-02-01

    Doppler test objects are used to characterise Doppler systems, both stand-alone systems and the Doppler part of so-called duplex scanners. The aim of the project partially presented here is the development and validation of an example of a Doppler test object fulfilling the requirements of the IEC 1685. The project has been carried out by nine partners of five European countries and has been funded by the European Commission. The flow Doppler test object is composed of: tissue mimicking material (TMM), blood mimicking fluid (BMF), tube (embedded in the TMM and carrying the BMF), tank flow system, including a pump and a flow meter. In the normative part of the IEC 1685, requirements are given for the values of acoustical parameters of TMM and BMF such as sound velocity, attenuation and backscattering. For BMF, requirements are given also for values of density and viscosity. In an informative (but not compulsory) annex, a description is given of a flow test object meeting these requirements as an example. 'example test object' developed during the project is composed of TMM based on agar and including SiC- and Al2O3-powders, BMF based on nylon particles suspended in water and glycerine, and a tube of c-flex, a silicon copolymer. Two tube sizes are used: 4.0 mm ID and 8.0 mm ID. During the project, very precise recipes have been developed for the composition and preparation of both TMM and BMF. Based on these recipes and a description of the construction in a design five flow test objects have been constructed in the laboratories of five participants. The test objects have been compared by measurements of the physical parameters and by Doppler measurements of the five test objects with the Doppler system. The measurements have been carried out by five observers. Inter-test object and inter-observer variabilities are determined, yielding information about usefulness of the parameters. PMID:9651595

  19. A Test Generation Framework for Distributed Fault-Tolerant Algorithms

    NASA Technical Reports Server (NTRS)

    Goodloe, Alwyn; Bushnell, David; Miner, Paul; Pasareanu, Corina S.

    2009-01-01

    Heavyweight formal methods such as theorem proving have been successfully applied to the analysis of safety critical fault-tolerant systems. Typically, the models and proofs performed during such analysis do not inform the testing process of actual implementations. We propose a framework for generating test vectors from specifications written in the Prototype Verification System (PVS). The methodology uses a translator to produce a Java prototype from a PVS specification. Symbolic (Java) PathFinder is then employed to generate a collection of test cases. A small example is employed to illustrate how the framework can be used in practice.

  20. A Study of a Network-Flow Algorithm and a Noncorrecting Algorithm for Test Assembly.

    ERIC Educational Resources Information Center

    Armstrong, R. D.; And Others

    1996-01-01

    When the network-flow algorithm (NFA) and the average growth approximation algorithm (AGAA) were used for automated test assembly with American College Test and Armed Services Vocational Aptitude Battery item banks, results indicate that reasonable error in item parameters is not harmful for test assembly using NFA or AGAA. (SLD)

  1. Noteworthy mammal distribution records for the Nevada test site

    SciTech Connect

    Medica, P.A.

    1989-06-01

    Nevada Test Site records for the gray fox Urocyon cinereoargenteus scottii and the dark kangaroo mouse Microdipodops meqacephalus sabulonis are substantiated, and a range extension for Mustela frenata nevadensis documented. 17 refs.

  2. Blood trauma testing of CentriMag and RotaFlow centrifugal flow devices: a pilot study.

    PubMed

    Sobieski, Michael A; Giridharan, Guruprasad A; Ising, Mickey; Koenig, Steven C; Slaughter, Mark S

    2012-08-01

    Mechanical circulatory assist devices that provide temporary support in heart failure patients are needed to enable recovery or provide a bridge to decision. Minimizing risk of blood damage (i.e., hemolysis) with these devices is critical, especially if the length of support needs to be extended. Hematologic responses of the RotaFlow (Maquet) and CentriMag (Thoratec) temporary support devices were characterized in an in vitro feasibility study. Paired static mock flow loops primed with fresh bovine blood (700 mL, hematocrit [Hct] = 25 ± 3%, heparin titrated for activated clotting time >300 s) pooled from a single-source donor were used to test hematologic responses to RotaFlow (n = 2) and CentriMag (n = 2) simultaneously. Pump differential pressures, temperature, and flow were maintained at 250 ± 10 mm Hg, 25 ± 2°C, and 4.2 ± 0.25 L/min, respectively. Blood samples (3 mL) were collected at 0, 60, 120, 180, 240, 300, and 360 min after starting pumps in accordance with recommended Food and Drug Administration and American Society for Testing and Materials guidelines. The CentriMag operated at a higher average pump speed (3425 rpm) than the RotaFlow (3000 rpm) while maintaining similar constant flow rates (4.2 L/min). Hematologic indicators of blood trauma (hemoglobin, Hct, platelet count, plasma free hemoglobin, and white blood cell) for all measured time points as well as normalized and modified indices of hemolysis were similar (RotaFlow: normalized index of hemolysis [NIH] =  0.021 ± 0.003 g/100 L, modified index of hemolysis [MIH] = 3.28 ± 0.52 mg/mg compared to CentriMag: NIH =  0.041 ± 0.010 g/100 L, MIH = 6.08 ± 1.45 mg/mg). In this feasibility study, the blood trauma performance of the RotaFlow was similar or better than the CentriMag device under clinically equivalent, worst-case test conditions. The RotaFlow device may be a more cost-effective alternative to

  3. 42 CFR 84.94 - Gas flow test; closed-circuit apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Gas flow test; closed-circuit apparatus. 84.94 Section 84.94 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OCCUPATIONAL SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.94 Gas flow...

  4. Flow for Exercise Adherence: Testing an Intrinsic Model of Health Behavior

    ERIC Educational Resources Information Center

    Petosa, R. Lingyak; Holtz, Brian

    2013-01-01

    Background: Health behavior theory generally does not include intrinsic motivation as a determinate of health practices. Purpose: The purpose of this study was to test the flow theory of exercise adherence. Flow theory posits that exercise can be intrinsically rewarding if the experiences of self/time transcendence and control/mastery are achieved…

  5. ANGULAR FLOW INSENSITIVE PITOT TUBE SUITABLE FOR USE WITH STANDARD STACK TESTING EQUIPMENT

    EPA Science Inventory

    Five pitot tube designs were tested under various gas flow conditions for accuracy in measuring static and total pressure. The static- and impact-pressure measuring tubes least affected by angular flow were combined and then evaluated in the presence of standard particulate sampl...

  6. Noteworthy mammal distribution records for the Nevada Test Site

    SciTech Connect

    Medica, P.A. )

    1990-03-01

    Previous reports on the mammals of the Nevada Test Site, Nye County, Nevada, indicate the presence of 46 species (42 terrestrial mammals and 4 bats). Under a new project entitled Basic Environmental Compliance and Monitoring Program at the Nevada Test Site, two previously uncollected species of mammals were obtained, and a range extension for a third species was documented during the 1988 sampling season. Voucher specimens have been deposited at the Nevada State Museum in Las Vegas, Nevada.

  7. Delta diagram based test for the Halphen (A and B) and the Gamma distributions

    NASA Astrophysics Data System (ADS)

    El Adlouni, Salaheddine; Bobée, Bernard

    2014-05-01

    The most used statistical distributions to fit extreme value data in hydrology, can be regrouped in three classes: class C of regularly varying distributions and class D of sub exponential distributions, depending on their tail behaviour. The Halphen distributions (Halphen type A (HA) and Halphen type B (HB)) have both the Gamma (G2) distribution as limiting case and all these three distributions belong to the class D and can be displayed in the (Delta1 = ln(A/G); Delta2 = ln(G/H)) moment ratio diagram based on Geometric (G), Arithmetic (A) and Harmonic (H) means. In this study, a statistical test for discriminating between HA, HB and the Gamma distribution is developed. The methodology is based on Monte Carlo simulation for (1) the determination of the confidence regions around the Gamma curve for each fixed couple (Delta1 , Delta2) and (2) the study of the power of the proposed test for both alternatives HA and HB distributions and comparison with the Likelihood Ratio Test (LRT). Results showed that the test is powerful especially for high values of skewness and is far better than the LRT. This test will be included, shortly, in Decision Support System (DSS) of the HYFRAN-PLUS software. Key words: Halphen distributions, Gamma distribution, Heavy tailed distribution, Monte Carlo simulation, (Delta1 , Delta2) diagram, power of the test, HYFRAN-PLUS.

  8. Near-well nonlinear flow identified by various displacement well response testing.

    PubMed

    Zenner, Matthias A

    2009-01-01

    The impact of nonlinear flow phenomena on well response tests is still not completely understood today. With the present paper, a set of 10 well response tests is investigated. The tests were conducted in a fractured Devonian limestone formation close to the western national border of Germany. The test design incorporates a packer as well as different solid cylinders to initiate a series of slug-injection and slug-withdrawal tests by various initial displacements. Nonlinear response characteristics were observed in the course of the tests, which cannot be explained by tubing-controlled flow inside the cased well. The analysis shows that the nonlinear response characteristics are likely to be either formation controlled according to non-Darcian flow developing in a high-conductivity fracture compartment of the tested limestone formation or a consequence of a severe well inefficiency caused by some sort of screen clogging. This inference is obtained from analyzing the data by a nonlinear well response test model, which differentiates between wellbore internal hydraulic head losses and a generalized rate-dependent skin effect accounting for nonlinear flow processes in the vicinity of the well. The potential of identifying near-well nonlinear flow by various displacement well response testing may indicate this methodology to be a valuable complement to modern high-resolution borehole imaging techniques used when characterizing fractured reservoirs and the tightness of fractured reservoir cap rocks. PMID:19245376

  9. Fiber optic distributed temperature sensor mapping of a jet-mixing flow field

    DOE PAGESBeta

    Lomperski, Stephen; Gerardi, Craig; Pointer, William David

    2015-03-04

    In this paper, we introduce the use of a Rayleigh backscatter-based distributed fiber optic sensor to map the temperature field in air flow for a thermal fatigue application. The experiment involves a pair of air jets at 22 and 70°C discharging from 136 mm hexagonal channels into a 1 × 1 × 1.7 m tank at atmospheric pressure. A 40 m-long, Φ155 µm fiber optic sensor was wound back and forth across the tank midplane to form 16 horizontal measurement sections with a vertical spacing of 51 mm. This configuration generated a 2D temperature map with 2800 data points overmore » a 0.76 × 1.7 m plane. Fiber optic sensor readings were combined with PIV and infrared measurements to relate flow field characteristics to the thermal signature of the tank lid. The paper includes sensor stability data and notes issues encountered using the distributed temperature sensor in a flow field. In conclusion, sensors are sensitive to strain and humidity, and so accuracy relies upon strict control of both.« less

  10. Fiber optic distributed temperature sensor mapping of a jet-mixing flow field

    SciTech Connect

    Lomperski, Stephen; Gerardi, Craig; Pointer, William David

    2015-03-04

    In this paper, we introduce the use of a Rayleigh backscatter-based distributed fiber optic sensor to map the temperature field in air flow for a thermal fatigue application. The experiment involves a pair of air jets at 22 and 70°C discharging from 136 mm hexagonal channels into a 1 × 1 × 1.7 m tank at atmospheric pressure. A 40 m-long, Φ155 µm fiber optic sensor was wound back and forth across the tank midplane to form 16 horizontal measurement sections with a vertical spacing of 51 mm. This configuration generated a 2D temperature map with 2800 data points over a 0.76 × 1.7 m plane. Fiber optic sensor readings were combined with PIV and infrared measurements to relate flow field characteristics to the thermal signature of the tank lid. The paper includes sensor stability data and notes issues encountered using the distributed temperature sensor in a flow field. In conclusion, sensors are sensitive to strain and humidity, and so accuracy relies upon strict control of both.

  11. Correlation of steel corrosion in pipe flow with jet impingement and rotating cylinder tests

    SciTech Connect

    Efird, K.D.; Wright, E.J.; Boros, J.A.; Hailey, T.G.

    1993-12-01

    The relationship of laboratory fluid flow corrosion test techniques to flow-accelerated corrosion in field applications and the parameters required to apply laboratory data effectively in the field were studied. Single-phase, aqueous, sweet corrosion of steel in turbulent pipe flow was correlated to corrosion in jet impingement and rotating cylinder tests. All tests were conducted simultaneously, using the same test fluid to minimize environmental variables and to allow a direct, realistic comparison of test methods. Rotating cylinder electrode corrosion rates did not correlate with pipe flow based on wall shear stress or mass transfer for flow-accelerated corrosion of carbon (C) steel in the environment studied. Jet impingement corrosion rates for the test ring at r/r{sub 0} = 3 correlated with pipe flow based on wall shear stress. The general equation for flow-accelerated corrosion of C steel under turbulent flow conditions in this environment was expressed as: R = a{tau}{sub w}{sup b} where R was the C steel corrosion rate in mm/y and {tau}{sub w} was the wall shear stress in N/m{sup 2}. Effects of solution chemistry were contained in the equation coefficient and exponent and require further experimental definition. The physical fluid and hydrodynamic parameters were included in {tau}{sub w}. Use of wall shear stress as the correlating factor did not imply a shear mechanism for corrosion acceleration. Wall shear stress was found to be a hydrodynamic factor that can be used effectively to relate fluid flow in different geometries, allowing valid comparison of laboratory tests and field operations.

  12. Testing pulse density distribution for terrestrial gamma ray flashes

    NASA Astrophysics Data System (ADS)

    Abukhaled, Marwan; Allen, Edward; Guessoum, Nidhal

    2014-07-01

    Maximum likelihood fits for the time profiles of 51 terrestrial gamma ray flashes (from Compton Gamma Ray Observatory/Burst and Transient Source Experiment and Fermi Gamma-Ray Space Telescope/Gamma-Ray Burst Monitor) were calculated for five proposed probability densities. A lognormal distribution, which had been used by other researchers, was compared with piecewise Gaussian, piecewise exponential, inverse Gaussian, and Ornstein-Uhlenbeck probability density functions. The piecewise Gaussian and piecewise exponential distributions are justified physically through assuming exponential growth and decay of the electron avalanches which result in the gamma ray bursts and are therefore highly relevant in this context. However, identifying the electron avalanche phenomenon as a form of stochastic exit time process, the inverse Gaussian and Ornstein-Uhlenbeck are reasonable alternatives. Results of the maximum likelihood calculations indicate that the five probability densities fit the gamma ray pulse data equally well. By this comparison, our aim is to indicate to terrestrial gamma ray flash researchers these other at least equally valid distribution functions, which may give insights into the physical processes that the electrons (and the positrons) undergo in the gamma ray flashes.

  13. Experimental onset of flow instability testing by Creare, Inc. Book 1

    SciTech Connect

    Coutts, D.A.

    1992-11-01

    Flow excursions can occur during subcooled heated flow if the supply system is not adequate to meet the heated channel pressure demand. Available experimental flow instability (FI) data for ribbed annuli such as used in the SRS production reactors is very limited. Creare Inc. completed a series of FI tests which included two annular geometries; one of these included metallic ribs which separated the annulus into four sub-channels. This report summarizes the results of the onset of flow instability (OFI) testing which was completed by Creare in support of the SRS Reactor Restart Program. A copy of the final test report has been attached and the archival locations for the supporting documentation and electronic test data is also included. The purpose of this report is to: Archive the Creare Program data; inspect the data which has been archived; review the results presented by Creare; and evaluate if the Creare Program data may be used in critical applications.

  14. A flight test of laminar flow control leading-edge systems

    NASA Technical Reports Server (NTRS)

    Fischer, M. C.; Wright, A. S., Jr.; Wagner, R. D.

    1983-01-01

    NASA's program for development of a laminar flow technology base for application to commercial transports has made significant progress since its inception in 1976. Current efforts are focused on development of practical reliable systems for the leading-edge region where the most difficult problems in applying laminar flow exist. Practical solutions to these problems will remove many concerns about the ultimate practicality of laminar flow. To address these issues, two contractors performed studies, conducted development tests, and designed and fabricated fully functional leading-edge test articles for installation on the NASA JetStar aircraft. Systems evaluation and performance testing will be conducted to thoroughly evaluate all system capabilities and characteristics. A simulated airline service flight test program will be performed to obtain the operational sensitivity, maintenance, and reliability data needed to establish that practical solutions exist for the difficult leading-edge area of a future commercial transport employing laminar flow control.

  15. In vitro blood flow model with physiological wall shear stress for hemocompatibility testing-An example of coronary stent testing.

    PubMed

    Engels, Gerwin Erik; Blok, Sjoerd Leendert Johannes; van Oeveren, Willem

    2016-01-01

    Hemocompatibility of blood contacting medical devices has to be evaluated before their intended application. To assess hemocompatibility, blood flow models are often used and can either consist of in vivo animal models or in vitro blood flow models. Given the disadvantages of animal models, in vitro blood flow models are an attractive alternative. The in vitro blood flow models available nowadays mostly focus on generating continuous flow instead of generating a pulsatile flow with certain wall shear stress, which has shown to be more relevant in maintaining hemostasis. To address this issue, the authors introduce a blood flow model that is able to generate a pulsatile flow and wall shear stress resembling the physiological situation, which the authors have coined the "Haemobile." The authors have validated the model by performing Doppler flow measurements to calculate velocity profiles and (wall) shear stress profiles. As an example, the authors evaluated the thrombogenicity of two drug eluting stents, one that was already on the market and one that was still under development. After identifying proper conditions resembling the wall shear stress in coronary arteries, the authors compared the stents with each other and often used reference materials. These experiments resulted in high contrast between hemocompatible and incompatible materials, showing the exceptional testing capabilities of the Haemobile. In conclusion, the authors have developed an in vitro blood flow model which is capable of mimicking physiological conditions of blood flow as close as possible. The model is convenient in use and is able to clearly discriminate between hemocompatible and incompatible materials, making it suitable for evaluating the hemocompatible properties of medical devices. PMID:27435456

  16. Computational Fluid Dynamics Modeling of The Dalles Project: Effects of Spill Flow Distribution Between the Washington Shore and the Tailrace Spillwall

    SciTech Connect

    Rakowski, Cynthia L.; Serkowski, John A.; Richmond, Marshall C.

    2010-12-01

    The U.S. Army Corps of Engineers-Portland District (CENWP) has ongoing work to improve the survival of juvenile salmonids (smolt) migrating past The Dalles Dam. As part of that effort, a spillwall was constructed to improve juvenile egress through the tailrace downstream of the stilling basin. The spillwall was designed to improve smolt survival by decreasing smolt retention time in the spillway tailrace and the exposure to predators on the spillway shelf. The spillwall guides spillway flows, and hence smolt, more quickly into the thalweg. In this study, an existing computational fluid dynamics (CFD) model was modified and used to characterize tailrace hydraulics between the new spillwall and the Washington shore for six different total river flows. The effect of spillway flow distribution was simulated for three spill patterns at the lowest total river flow. The commercial CFD solver, STAR-CD version 4.1, was used to solve the unsteady Reynolds-averaged Navier-Stokes equations together with the k-epsilon turbulence model. Free surface motion was simulated using the volume-of-fluid (VOF) technique. The model results were used in two ways. First, results graphics were provided to CENWP and regional fisheries agency representatives for use and comparison to the same flow conditions at a reduced-scale physical model. The CFD results were very similar in flow pattern to that produced by the reduced-scale physical model but these graphics provided a quantitative view of velocity distribution. During the physical model work, an additional spill pattern was tested. Subsequently, that spill pattern was also simulated in the numerical model. The CFD streamlines showed that the hydraulic conditions were likely to be beneficial to fish egress at the higher total river flows (120 kcfs and greater, uniform flow distribution). At the lowest flow case, 90 kcfs, it was necessary to use a non-uniform distribution. Of the three distributions tested, splitting the flow evenly between

  17. Computer tomography of flows external to test models

    NASA Technical Reports Server (NTRS)

    Prikryl, I.; Vest, C. M.

    1982-01-01

    Computer tomographic techniques for reconstruction of three-dimensional aerodynamic density fields, from interferograms recorded from several different viewing directions were studied. Emphasis is on the case in which an opaque object such as a test model in a wind tunnel obscures significant regions of the interferograms (projection data). A method called the Iterative Convolution Method (ICM), existing methods in which the field is represented by a series expansions, and analysis of real experimental data in the form of aerodynamic interferograms are discussed.

  18. Study and optimization of gas flow and temperature distribution in a Czochralski configuration

    NASA Astrophysics Data System (ADS)

    Fang, H. S.; Jin, Z. L.; Huang, X. M.

    2012-12-01

    The Czochralski (Cz) method has virtually dominated the entire production of bulk single crystals with high productivity. Since the Cz-grown crystals are cylindrical, axisymmetric hot zone arrangement is required for an ideally high-quality crystal growth. However, due to three-dimensional effects the flow pattern and temperature field are inevitably non-axisymmetric. The grown crystal suffers from many defects, among which macro-cracks and micro-dislocation are mainly related to inhomogeneous temperature distribution during the growth and cooling processes. The task of the paper is to investigate gas partition and temperature distribution in a Cz configuration, and to optimize the furnace design for the reduction of the three-dimensional effects. The general design is found to be unfavorable to obtain the desired temperature conditions. Several different types of the furnace designs, modified at the top part of the side insulation, are proposed for a comparative analysis. The optimized one is chosen for further study, and the results display the excellence of the proposed design in suppression of three-dimensional effects to achieve relatively axisymmetric flow pattern and temperature distribution for the possible minimization of thermal stress related crystal defects.

  19. Regional measurements of /sup 14/Cmisonidazole distribution and blood flow in subcutaneous RT-9 experimental tumors

    SciTech Connect

    Blasberg, R.; Horowitz, M.; Strong, J.; Molnar, P.; Patlak, C.; Owens, E.; Fenstermacher, J.

    1985-04-01

    Regional (/sup 14/C)misonidazole-derived radioactivity (MISO*) was measured by quantitative autoradiography in s.c. RT-9 experimental tumors 0.5, 2, and 4 h after an i.v. bolus (25 mg) and constant infusion (10 mg/h) in rats. Misonidazole (MISO) concentration in plasma, tumor, and other tissues was also measured by high-pressure liquid chromatography. The distribution of MISO* in the tumors always resulted in a characteristic pattern with high peripheral and low central values. The high-activity regions in the tumor rim achieved tissue: plasma MISO* activity ratios of 0.97 and 2.2 by 0.5 and 4 h, respectively; for central tumor regions, this ratio was 0.20 and 0.32 for the same periods, respectively. The limited distribution of MISO* to central tumor regions could be correlated to low values of blood flow (measured with (/sup 131/I)iodoantipyrine) and to diffusion from peripheral tumor regions. Low blood flow in the central regions of these tumors will significantly limit the distribution of MISO and other drugs to viable-appearing cells in these areas and could account in part for the failures of chemotherapy in certain solid tumors. Pharmacokinetic modeling indicates that 1 to 9 h may be necessary for MISO concentrations in some tumor regions to reach 50% of that in plasma.

  20. Regulation of blood flow distribution in skeletal muscle: role of erythrocyte-released ATP

    PubMed Central

    Ellsworth, Mary L; Sprague, Randy S

    2012-01-01

    The maintenance of adequate tissue O2 levels in skeletal muscle is vital for normal physiology and requires a well regulated and appropriately distributed convective O2 supply. Inherent in this fundamental physiological process is the requirement for a mechanism which both senses tissue O2 need and locally adjusts flow to appropriately meet that need. Over the past several years we and others have suggested that, in skeletal muscle, O2 carrying erythrocytes participate in the regulation of total blood flow and its distribution by releasing ATP. Importantly, the release of this vasoactive molecule must be both rapid and well controlled if it is to serve an important physiological role. Here we provide insights into three distinct regulated signalling pathways within the erythrocyte that are activated by exposure to reduced O2 tension or in response to binding of agonists to the prostacyclin or β-adrenergic receptors. Although much has been learned about the role of the erythrocyte in perfusion of skeletal muscle, much remains to be understood. However, what is clear is that the long established passive carrier of O2 also contributes to the regulation of the distribution of microvascular perfusion in skeletal muscle by virtue of its capacity to release ATP. PMID:22586223

  1. Optimization and testing of the tomographic method of velocity measurement in the flow volume

    NASA Astrophysics Data System (ADS)

    Bilsky, A. V.; Lozhkin, V. A.; Markovich, D. M.; Tokarev, M. P.; Shestakov, M. V.

    2011-12-01

    The optic noncontact method of velocity field measurement in the flow volume is considered in this paper for the purposes of hydroaerodynamic experiment. The essence of this method is measurement of particles motion in the flow during short periods between laser pulses. This study offers and implements several algorithmic optimizations, allowing data processing time reduction. It is shown that application of threshold background filtering on the recorded projections (particle images) and fast estimation of initial intensity distribution in the volume allows increasing the speed of tomographic reconstruction algorithm two or three times. Reconstruction accuracy and errors in determination of particle shift were studied in this work using artificial images. The described tomographic method for the velocity field estimation in the flow volume was used for diagnostics of a turbulent submerged jet flowing into a narrow channel. The application of developed approaches in experiment allowed us to obtain spatial distribution of the average velocity field and instantaneous velocity fields in the measurement area.

  2. Experiment 2074: post-drilling reservoir flow testing through EE-3A first revision

    SciTech Connect

    Brown, Donald W.; Robinson, Bruce A.

    1987-11-20

    As previously outlined in memorandum ESS-4-87-305 (11/12/87), EE-3A will be pressurized with the Kobe pumps for the next week, and then a sequence of reservoir flow tests and logs will be conducted for a one to two week period beginning Tuesday, 12/1/87. The purpose of this memorandum is to better define this flow test and sequence of logs, organized as a "formal" experiment.

  3. Vertical distribution of fluid velocity and suspended sediment in open channel turbulent flow

    NASA Astrophysics Data System (ADS)

    Pal, Debasish; Ghoshal, Koeli

    2016-06-01

    To predict the vertical distribution of streamwise fluid velocity and suspended sediment concentration profiles in an open channel turbulent flow, we derive a theoretical model here based on the Reynolds averaged Navier-Stokes equation and the mass conservation equations of solid and fluid phases. The model includes the effects of secondary current in terms of the vertical velocity of fluid, additional vertical velocity of fluid due to the suspended particles, mixing length of sediment-laden flow and settlement of the suspended particles due to gravitational force. We numerically solve our model as coupled differential equations and the obtained solution agrees well with a wide spectrum of experimental data. A detailed error analysis asserts the superior determination accuracy of our model in comparison to the traditional log-law and Rouse equation and other existing theoretical models. The significance of the turbulent features included in the model and the importance of their co-existence to compute velocity and concentration profiles are explained. In sharp contrast to the previous researchers, the present model has significant contribution in unveiling several latent phenomena of particle-turbulence interaction throughout the flow region. The model can also address various crucial phenomena of velocity and concentration profiles that occur during flow in real situation.

  4. Technology of forced flow and once-through boiling: A survey. [pressure distribution

    NASA Technical Reports Server (NTRS)

    Poppendieck, H. F.; Sabin, C. M.

    1975-01-01

    Representative boiling heat transfer and pressure drop information obtained primarily from past NASA and AEC programs is presented which is applicable to forced flow and once-through boiler systems. The forced convection boiler has a number of advantages: little possibility of flow mal-distribution; heat transfer characteristics are usually consistent; and conductances are predictable, so that higher heat fluxes may be employed with safety (which leads to more compact, lighter weight equipment). It was found that in gas-fired systems particularly, the controlling heat transfer resistance may be on the hot side, so that increased fluxes would require extended surfaces. If in a power generation system the working fluid is very expensive, a forced flow boiler can be designed especially for small holdup volume. If the fluid is temperature sensitive, the boiling side wall temperatures can be tailored to maintain maximum heat transfer rates without overheating the fluid. The forced flow and once-through configurations may be the only type which can satisfy a specific need (such as the automotive Rankine cycle power plant design having a very short time-response boiler).

  5. Holographic measurement of wall stress distribution and 3D flow over a surface textured by microfibers

    NASA Astrophysics Data System (ADS)

    Bocanegra, Humberto; Gorumlu, Seder; Aksak, Burak; Castillo, Luciano; Sheng, Jian

    2015-11-01

    Understanding how fluid flow interacts with micro-textured surfaces is crucial for a broad range of key biological processes and engineering applications including particle dispersion, pathogenic infections, and drag manipulation by surface topology. Existing methods, such as μPIV, suffers from low spatial resolution and fail to track tracer particle motion very close to a rough surface and within roughness elements. In this paper, we present a technique that combines high speed digital holographic microscopy (DHM) with a correlation based de-noising algorithm to overcome the optical interference generated by surface roughness and to capture a large number of 3D particle trajectories. It allows us to obtain a 3D velocity field with an uncertainty of 0.01% and 2D wall shear stress distribution at the resolution of ~ 65 μPa. Applying the technique to a microfluidics with a surface textured by microfibers, we find that the flow is three-dimensional and complex. While the microfibers affect the velocity flow field locally, their presence is felt globally in terms of wall shear stresses. The study of effect of microfiber patterns and flow characteristics on skin frictions are ongoing and will be reported.

  6. Application of Entropy Concept for Shear Stress Distribution in Laminar Pipe Flow

    NASA Astrophysics Data System (ADS)

    Choo, Yeon Moon; Choo, Tai Ho; Jung, Donghwi; Seon, Yun Gwan; Kim, Joong Hoon

    2016-04-01

    In the river fluid mechanics, shear stress is calculated from frictional force caused by viscosity and fluctuating velocity. Traditional shear stress distribution equations have been widely used because of their simplicity. However, they have a critical limitation of requiring energy gradient which is generally difficult to estimate in practice. Especially, measuring velocity/velocity gradient on the boundary layer is difficult in practice. It requires point velocity throughout the entire cross section to calculate velocity gradient. This study proposes shear stress distribution equations for laminar flow based on entropy theory using mean velocity and entropy coefficient. The proposed equations are demonstrated and compared with measured shear stress distribution using Nikuradse's data. Results showed that the coefficient of determination is around 0.99 indicating that the proposed method well describes the true shear stress distribution. Therefore, it was proved that shear stress distribution can be easily and accurately estimated by using the proposed equations. (This research was supported by a gran(13AWMP-B066744-01) from Advanced Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean Government)

  7. Modeling Heat Flow for a Distributed Moving Heat Source in Micro-Laser Welding of Plastics

    NASA Astrophysics Data System (ADS)

    Grewell, David; Benatar, Avraham

    2004-06-01

    Polymer use in micro-devices, especially in the medical industry has been rapidly increasing. During assembly of micro-devices it is desirable to produce weld joints that are about 100 μm in width. This paper reviews the modeling of heat flow during through transmission infrared micro-welding of plastic using fiber coupled laser diodes. Two models were used to predict the temperature distributions within welded samples. Both models were based on a moving heat source and moving coordinate system. For the simpler model a moving point heat source was used and for the more complex model a Gaussian distributed heat source was used. It was found that the distributed model can accurately predict temperature fields in plastic laser welds for all ranges of the parameters evaluated. However, the point heat source model was only able to accurately predict temperature fields with a relatively small laser focal spot (25 μm). In addition it was found that for micro-welding of plastics, when the dimensionless distribution parameter is less than two, a point heat source model predicts similar widths to those predicted by a distributed heat source model.

  8. Numerical tests of constitutive laws for dense granular flows.

    PubMed

    Lois, Gregg; Lemaître, Anaël; Carlson, Jean M

    2005-11-01

    We numerically and theoretically study the macroscopic properties of dense, sheared granular materials. In this process we first consider an invariance in Newton's equations, explain how it leads to Bagnold's scaling, and discuss how it relates to the dynamics of granular temperature. Next we implement numerical simulations of granular materials in two different geometries--simple shear and flow down an incline--and show that measurements can be extrapolated from one geometry to the other. Then we observe nonaffine rearrangements of clusters of grains in response to shear strain and show that fundamental observations, which served as a basis for the shear transformation zone (STZ) theory of amorphous solids [M. L. Falk and J. S. Langer, Phys. Rev. E. 57, 7192 (1998); M.R.S. Bull 25, 40 (2000)], can be reproduced in granular materials. Finally we present constitutive equations for granular materials as proposed by Lemaître [Phys. Rev. Lett. 89, 064303 (2002)], based on the dynamics of granular temperature and STZ theory, and show that they match remarkably well with our numerical data from both geometries. PMID:16383599

  9. Magnetic field distribution in the plasma flow generated by a plasma focus discharge

    SciTech Connect

    Mitrofanov, K. N.; Krauz, V. I. Myalton, V. V.; Velikhov, E. P.; Vinogradov, V. P.; Vinogradova, Yu. V.

    2014-11-15

    The magnetic field in the plasma jet propagating from the plasma pinch region along the axis of the chamber in a megajoule PF-3 plasma focus facility is studied. The dynamics of plasma with a trapped magnetic flow is analyzed. The spatial sizes of the plasma jet region in which the magnetic field concentrates are determined in the radial and axial directions. The magnetic field configuration in the plasma jet is investigated: the radial distribution of the azimuthal component of the magnetic field inside the jet is determined. It is shown that the magnetic induction vector at a given point in space can change its direction during the plasma flight. Conclusions regarding the symmetry of the plasma flow propagation relative to the chamber axis are drawn.

  10. Distribution characteristics of pollutant transport in a turbulent two-phase flow.

    PubMed

    Khaldi, Nawel; Marzouk, Salwa; Mhiri, Hatem; Bournot, Philippe

    2015-04-01

    The distribution characteristics of pollutants released at varied rates and different vertical inlet positions of an open channel are investigated via a three-dimensional numerical model. Pollutants are injected from time-dependent sources in a turbulent free-surface flow. Numerical computations were carried out using Fluent 6.3, which is based on the finite volume approach. The air/water interface was modeled with the volume of fluid method (VOF). By focusing on investigating the influences of the flow on pollutants, it is found that with an increase of the injection rate, the pollutant concentration increases along the channel and the longitudinal dispersion is higher. On the other hand, it is noted that the point of injection modifies significantly the dispersion pattern of pollutant. These findings may be of great help in cost-effective scientific countermeasures to be taken into account for accident or planned pollutants discharged into a river. PMID:25567054

  11. Flow field distribution of liquid film of water lubricated bearing-rotor coupling systems

    NASA Astrophysics Data System (ADS)

    Hu, Q. L.; Hu, J. N.; Ye, X. Y.; Zhang, D. S.; Zheng, J. B.

    2016-05-01

    According to the desalination high-pressure pump water lubricated bearing-rotor coupling systems flow field distribution of liquid film in the starting transient process and its power transmission mechanism can lay the foundation of further exploring and judging lubrication state at the boot process. By using the computational fluid dynamics Fluent secondary development platform and calling the relevant DEFINE macro function to achieve the translation and rotation movement of the journal, we will use the dynamic grid technique to realize the automatic calculation and grid update of water lubricated bearings 3d unsteady liquid film flow field, and finally we will dispose the results of numerical simulation and get the pressure. When the eccentricity is large, film thickness was negatively correlated with the pressure, and positive with the velocity. Differential pressure was negatively correlated with velocity. When the eccentricity is small, film thickness is no significant relationship with differential pressure and velocity. Differential pressure has little difference with velocity.

  12. Impact of heterogeneous permeability distribution and salt transport on the groundwater flow of the Thuringian sedimentary basin

    NASA Astrophysics Data System (ADS)

    Zech, Alraune; Zehner, Björn; Kolditz, Olaf; Attinger, Sabine

    2016-04-01

    Ground water flow systems of the Thuringian Basin are studied by analyzing the fluid dynamics at this real world example of a shallow sedimentary basin. The impact of the permeability distribution and density differences on the flow velocity pattern, the salt concentration, and the temperature distribution is quantified by means of transient coupled simulations of fluid flow, heat, and mass transport processes. Simulations are performed with different permeabilities in the sedimentary layering and heterogeneous permeability distributions as well as with a non-constant fluid density. Three characteristic numbers are useful to describe the effects of permeability on the development of flow systems and subsurface transport: the relation of permeability between aquiclude and aquifer, the variance, and the correlation length of the log-normal permeability distribution. Density dependent flow due to concentration gradients is of minor importance for the distribution of the flow systems, but can lead to increased mixing dissolution of salt. Thermal convection is in general not present. The dominant driver of groundwater flow is the topography in combination with the permeability distribution. The results obtained for the Thuringian Basin give general insights into the dynamics of a small sedimentary basin due to the representative character of the basin structure as well as the transferability of the settings to other small sedimentary basins.

  13. Water Flow Simulation Test on Flow-Induced Oscillation of Thermowell in Prototype Fast Breeder Reactor “MONJU”

    NASA Astrophysics Data System (ADS)

    Kondo, Masaya; Anoda, Yoshinari

    Water flow simulation tests were performed on the flow-induced oscillations of the thermowell in the prototype fast breeder reactor (FBR), MONJU. The displacements of the target cylinder were measured, and the oscillation amplitudes, the frequency characteristics, and the phase relationships were estimated. The estimations showed that the oscillations of the target cylinder had a one-dimensional oscillation region in the in-line direction with symmetric vortices shedding and a two-dimensional oscillation region induced by alternative vortices. The phase estimation, carried out by a methodology using wavelet analysis and statistical analysis, indicated that the effect of the alternative vortices on the in-line oscillation was changed with the flow velocity.

  14. Genealogical Working Distributions for Bayesian Model Testing with Phylogenetic Uncertainty.

    PubMed

    Baele, Guy; Lemey, Philippe; Suchard, Marc A

    2016-03-01

    Marginal likelihood estimates to compare models using Bayes factors frequently accompany Bayesian phylogenetic inference. Approaches to estimate marginal likelihoods have garnered increased attention over the past decade. In particular, the introduction of path sampling (PS) and stepping-stone sampling (SS) into Bayesian phylogenetics has tremendously improved the accuracy of model selection. These sampling techniques are now used to evaluate complex evolutionary and population genetic models on empirical data sets, but considerable computational demands hamper their widespread adoption. Further, when very diffuse, but proper priors are specified for model parameters, numerical issues complicate the exploration of the priors, a necessary step in marginal likelihood estimation using PS or SS. To avoid such instabilities, generalized SS (GSS) has recently been proposed, introducing the concept of "working distributions" to facilitate--or shorten--the integration process that underlies marginal likelihood estimation. However, the need to fix the tree topology currently limits GSS in a coalescent-based framework. Here, we extend GSS by relaxing the fixed underlying tree topology assumption. To this purpose, we introduce a "working" distribution on the space of genealogies, which enables estimating marginal likelihoods while accommodating phylogenetic uncertainty. We propose two different "working" distributions that help GSS to outperform PS and SS in terms of accuracy when comparing demographic and evolutionary models applied to synthetic data and real-world examples. Further, we show that the use of very diffuse priors can lead to a considerable overestimation in marginal likelihood when using PS and SS, while still retrieving the correct marginal likelihood using both GSS approaches. The methods used in this article are available in BEAST, a powerful user-friendly software package to perform Bayesian evolutionary analyses. PMID:26526428

  15. Acoustic tests of a 15.2 centimeter-diameter potential flow convergent nozzle

    NASA Technical Reports Server (NTRS)

    Karchmer, A. M.; Dorsch, R. G.; Friedman, R.

    1974-01-01

    An experimental investigation of the jet noise radiated to the far field from a 15.2-cm-diam potential flow convergent nozzle has been conducted. Tests were made with unheated airflow over a range of subsonic nozzle exhaust velocities from 62 to 310m/sec. Mean and turbulent velocity measurements in the flow field of the nozzle exhaust indicated no apparent flow anomalies. Acoustic measurements yielded data uncontaminated by internal and/or background noise to velocities as low as 152m/sec. Finally, no significantly different acoustic characteristics between the potential flow nozzle and simple convergent nozzles were found.

  16. A mercury flow meter for ion thruster testing. [response time, thermal sensitivity

    NASA Technical Reports Server (NTRS)

    Wilbur, P. J.

    1973-01-01

    The theory of operation of the thermal flow meter is presented, and a theoretical model is used to determine design parameters for a device capable of measuring mercury flows in the range of 0 to 5 gm/hr. Flow meter construction is described. Tests performed using a positive displacement mercury pump as well as those performed with the device in the feed line of an operating thruster are discussed. A flow meter response time of about a minute and a sensitivity of about 10 mv/gm/hr are demonstrated. Additional work to relieve a sensitivity of the device to variations in ambient temperature is indicated to improve its quantitative performance.

  17. Estimating conditional probability of volcanic flows for forecasting event distribution and making evacuation decisions

    NASA Astrophysics Data System (ADS)

    Stefanescu, E. R.; Patra, A.; Sheridan, M. F.; Cordoba, G.

    2012-04-01

    event. Logistic regression - Here, we define A as a discrete r.v., while B is a continuous one. P(B) represents the probability of having a flow≥ hcritical at location B, while P(A) represents the probability of having a flow or non-flow at A. Bayes analysis - At this stage of the analysis we consider only the r.v. A, where P(A) represents the probability of having a flow≥ hcritical at location A. We are interested in observing how the probability of having a flow≥ hcritical at location A is changing when data from the model is taken into consideration. We assume a Beta prior distribution for P(A) and compute P(A/data) using Maximum Likelihood Estimation (MLE) approach. Bayesian network for causal relationships - Here, we are interested in more than two critical locations and we are able to incorporate using a directed acyclic graph the causal relationship between all the chosen locations. Marginal probabilities along with the joint probability associated with an event based on the "causal links" between variables.

  18. Live Virtual Constructive Distributed Test Environment Characterization Report

    NASA Technical Reports Server (NTRS)

    Murphy, Jim; Kim, Sam K.

    2013-01-01

    This report documents message latencies observed over various Live, Virtual, Constructive, (LVC) simulation environment configurations designed to emulate possible system architectures for the Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project integrated tests. For each configuration, four scenarios with progressively increasing air traffic loads were used to determine system throughput and bandwidth impacts on message latency.

  19. POPULATION DISTRIBUTION AROUND THE NEVADA TEST SITE, 1984

    EPA Science Inventory

    The Environmental Monitoring Systems Laboratory (EMSL-LV) conducts an offsite radiological safety program outside the boundaries of the Nevada Test Site. As part of this program, the EMSL-LV maintains a comprehensive and current listing of all rural offsite residents and dairy an...

  20. A lightweight, flow-based toolkit for parallel and distributed bioinformatics pipelines

    PubMed Central

    2011-01-01

    Background Bioinformatic analyses typically proceed as chains of data-processing tasks. A pipeline, or 'workflow', is a well-defined protocol, with a specific structure defined by the topology of data-flow interdependencies, and a particular functionality arising from the data transformations applied at each step. In computer science, the dataflow programming (DFP) paradigm defines software systems constructed in this manner, as networks of message-passing components. Thus, bioinformatic workflows can be naturally mapped onto DFP concepts. Results To enable the flexible creation and execution of bioinformatics dataflows, we have written a modular framework for parallel pipelines in Python ('PaPy'). A PaPy workflow is created from re-usable components connected by data-pipes into a directed acyclic graph, which together define nested higher-order map functions. The successive functional transformations of input data are evaluated on flexibly pooled compute resources, either local or remote. Input items are processed in batches of adjustable size, all flowing one to tune the trade-off between parallelism and lazy-evaluation (memory consumption). An add-on module ('NuBio') facilitates the creation of bioinformatics workflows by providing domain specific data-containers (e.g., for biomolecular sequences, alignments, structures) and functionality (e.g., to parse/write standard file formats). Conclusions PaPy offers a modular framework for the creation and deployment of parallel and distributed data-processing workflows. Pipelines derive their functionality from user-written, data-coupled components, so PaPy also can be viewed as a lightweight toolkit for extensible, flow-based bioinformatics data-processing. The simplicity and flexibility of distributed PaPy pipelines may help users bridge the gap between traditional desktop/workstation and grid computing. PaPy is freely distributed as open-source Python code at http://muralab.org/PaPy, and includes extensive

  1. Design and test of a natural laminar flow/large Reynolds number airfoil with a high design cruise lift coefficient

    NASA Technical Reports Server (NTRS)

    Kolesar, C. E.

    1987-01-01

    Research activity on an airfoil designed for a large airplane capable of very long endurance times at a low Mach number of 0.22 is examined. Airplane mission objectives and design optimization resulted in requirements for a very high design lift coefficient and a large amount of laminar flow at high Reynolds number to increase the lift/drag ratio and reduce the loiter lift coefficient. Natural laminar flow was selected instead of distributed mechanical suction for the measurement technique. A design lift coefficient of 1.5 was identified as the highest which could be achieved with a large extent of laminar flow. A single element airfoil was designed using an inverse boundary layer solution and inverse airfoil design computer codes to create an airfoil section that would achieve performance goals. The design process and results, including airfoil shape, pressure distributions, and aerodynamic characteristics are presented. A two dimensional wind tunnel model was constructed and tested in a NASA Low Turbulence Pressure Tunnel which enabled testing at full scale design Reynolds number. A comparison is made between theoretical and measured results to establish accuracy and quality of the airfoil design technique.

  2. Hot-Film and Hot-Wire Anemometry for a Boundary Layer Active Flow Control Test

    NASA Technical Reports Server (NTRS)

    Lenahan, Keven C.; Schatzman, David M.; Wilson, Jacob Samuel

    2013-01-01

    Unsteady active flow control (AFC) has been used experimentally for many years to minimize bluff-body drag. This technology could significantly improve performance of rotorcraft by cleaning up flow separation. It is important, then, that new actuator technologies be studied for application to future vehicles. A boundary layer wind tunnel was constructed with a 1ft-x-3ft test section and unsteady measurement instrumentation to study how AFC manipulates the boundary layer to overcome adverse pressure gradients and flow separation. This unsteady flow control research requires unsteady measurement methods. In order to measure the boundary layer characteristics, both hot-wire and hot-film Constant Temperature Anemometry is used. A hot-wire probe is mounted in the flow to measure velocity while a hot-film array lays on the test surface to measure skin friction. Hot-film sensors are connected to an anemometer, a Wheatstone bridge circuit with an output that corresponds to the dynamic flow response. From this output, the time varying flow field, turbulence, and flow reversal can be characterized. Tuning the anemometers requires a fan test on the hot-film sensors to adjust each output. This is a delicate process as several variables drastically affect the data, including control resistance, signal input, trim, and gain settings.

  3. Amplitude distribution and energy balance of small disturbances in plate flow

    NASA Technical Reports Server (NTRS)

    Schlichting, H

    1950-01-01

    The distribution of the correlation coefficient and of the amplitude of the disturbance velocities is calculated as a function of the distance from the wall for two neutral disturbances, one at the lower and one at the upper branch of the neutral stability curve. The energy balance of the disturbance motion is also investigated and it is found that as required for neutral stability the energy of the disturbance motion that is dissipated by viscosity is equal to the energy transferred to the disturbance motion from the main flow during one cycle.

  4. Testing of SLA-561V in NASA-Ames' Turbulent Flow Duct with Augmented Radiative Heating

    NASA Technical Reports Server (NTRS)

    Sepka, Steven A.; Kornienko, Robert S.; Radbourne, Chris A.

    2010-01-01

    As part of Mars Science Laboratory s (MSL) heatshield development program, SLA-561 was tested in NASA Ames Turbulent Flow Duct (TFD) Facility. For these tests, the TFD facility was modified to include a ceramic plate located in the wall opposite to the test model. Normally the TFD wall opposite to the test model is water-cooled steel. Installing a noncooled ceramic plate allows the ceramic to absorb convective heating and radiate the energy back to the test model as the plate heats up. This work was an effort to increase the severity of TFD test conditions. Presented here are the results from these tests.

  5. An Investigation of Methods for Improving Estimation of Test Score Distributions.

    ERIC Educational Resources Information Center

    Hanson, Bradley A.

    Three methods of estimating test score distributions that may improve on using the observed frequencies (OBFs) as estimates of a population test score distribution are considered: the kernel method (KM); the polynomial method (PM); and the four-parameter beta binomial method (FPBBM). The assumption each method makes about the smoothness of the…

  6. 10 CFR 431.193 - Test procedures for measuring energy consumption of distribution transformers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... procedures for measuring the energy efficiency of distribution transformers for purposes of EPCA are... EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Distribution Transformers Test Procedures... 10 Energy 3 2012-01-01 2012-01-01 false Test procedures for measuring energy consumption...

  7. 10 CFR 431.193 - Test procedures for measuring energy consumption of distribution transformers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... procedures for measuring the energy efficiency of distribution transformers for purposes of EPCA are... EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Distribution Transformers Test Procedures... 10 Energy 3 2010-01-01 2010-01-01 false Test procedures for measuring energy consumption...

  8. 10 CFR 431.193 - Test procedures for measuring energy consumption of distribution transformers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... procedures for measuring the energy efficiency of distribution transformers for purposes of EPCA are... EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Distribution Transformers Test Procedures... 10 Energy 3 2014-01-01 2014-01-01 false Test procedures for measuring energy consumption...

  9. 10 CFR 431.193 - Test procedures for measuring energy consumption of distribution transformers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... procedures for measuring the energy efficiency of distribution transformers for purposes of EPCA are... EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Distribution Transformers Test Procedures... 10 Energy 3 2013-01-01 2013-01-01 false Test procedures for measuring energy consumption...

  10. 10 CFR 431.193 - Test procedures for measuring energy consumption of distribution transformers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... procedures for measuring the energy efficiency of distribution transformers for purposes of EPCA are... EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Distribution Transformers Test Procedures... 10 Energy 3 2011-01-01 2011-01-01 false Test procedures for measuring energy consumption...

  11. NASA Ames Laminar Flow Supersonic Wind Tunnel (LFSWT) Tests of a 10 deg Cone at Mach 1.6

    NASA Technical Reports Server (NTRS)

    Wolf, Stephen W. D.; Laub, James A.

    1997-01-01

    This work is part of the ongoing qualification of the NASA Ames Laminar Flow Supersonic Wind Tunnel (LFSWT) as a low-disturbance (quiet) facility suitable for transition research. A 10 deg cone was tested over a range of unit Reynolds numbers (Re = 2.8 to 3.8 million per foot (9.2 to 12.5 million per meter)) and angles of incidence (O deg to 10 deg) at Mach 1.6. The location of boundary layer transition along the cone was measured primarily from surface temperature distributions, with oil flow interferometry and Schlieren flow visualization providing confirmation measurements. With the LFSWT in its normal quiet operating mode, no transition was detected on the cone in the test core, over the Reynolds number range tested at zero incidence and yaw. Increasing the pressure disturbance levels in the LFSWT test section by a factor of five caused transition onset on the cone within the test core, at zero incidence and yaw. When operating the LFSWT in its normal quiet mode, transition could only be detected in the test core when high angles of incidence (greater than 5 deg) for cones were set. Transition due to elevated pressure disturbances (Tollmien-Schlichting) and surface trips produced a skin temperature rise of order 4 F (2.2 C). Transition due to cross flows on the leeward side of the cone at incidence produced a smaller initial temperature rise of only order 2.5 F (1.4 C), which indicates a slower transition process. We can conclude that these cone tests add further proof that the LFSWT test core is normally low-disturbance (pressure fluctuations greater than 0.1%), as found by associated direct flow quality measurements discussed in this report. Furthermore, in a quiet test environment, the skin temperature rise is sensitive to the type of dominant instability causing transition. The testing of a cone in the LFSWT provides an excellent experiment for the development of advanced transition detection techniques.

  12. Developing a Framework for Testing Distributed Hydrologic Models at the Catchment Scale - Examples of Test Model Runs for Event Based and Long Term Simulations

    NASA Astrophysics Data System (ADS)

    Cristea, N. C.; Kampf, S. K.; Mirus, B. B.; Loague, K.; Burges, S. J.

    2008-12-01

    We develop a testing framework for distributed hydrologic models at the catchment scale using the hypothetical reality concept. The hypothetical reality, considered an error-free hydrologic response modeled after the 10.5-ha Tarrawarra catchment in Australia, is generated using the sophisticated Integrated Hydrology Model (InHM) representing fully coupled 3D variably saturated subsurface and 2D surface flow with finite-element discretization. The hypothetical realty consists in a data set composed of two subsets designed to test long-term and event-based behavior of the test model. The first subset, a long term data set, comprises an 11-year variable time step time series of hydrograph output and head and saturation levels at 55 observation nodes as well as daily snapshots of head and saturation levels at all nodes in the domain. The second subset, short term data set, has the same type of output, but the domain snapshots are at a much finer time scale, every half hour for the selected rain events. Both data sets were obtained with the same InHM configuration but different output time steps. We use MODHMS (HydroGeoLogic, Inc.), a MODFLOW-based code that solves Richards equation for the 3-D variably saturated subsurface flow and the diffuse wave approximation 2D overland flow with finite differences in a coupled approach as the test model. We present examples of model testing scenarios with variations in spatial discretization, initial conditions, and representation of hydrologic processes. Future work includes testing of model parameters and soil characteristics, with the test model running first without any calibration and then with calibration against the hypothetical reality.

  13. Rolling flow wind tunnel tests of F-18 aircraft

    NASA Technical Reports Server (NTRS)

    Lutze, F. H.

    1980-01-01

    The lateral directional characteristics of an F-18 aircraft was investigated. Aerodynamic derivatives associated with pure roll rate, or the 'p' derivatives were obtained. The model is described and the procedures used to obtain and correct the data, and a graphical presentation of the results are presented. These results include graphs of the lateral directional static stability derivatives versus angle of attack, and the lateral directional force and moment coefficients versus nondimensional roll rate. Results are presented for several configurations including complete, complete without vertical tails, complete without horizontal tails, fuselage wing and fuselage alone. Each of these configuations was tested with and without wing leading edge extensions. The basic control surfaces were deflected and the results were investigated.

  14. Real-time flight test data distribution and display

    NASA Technical Reports Server (NTRS)

    Nesel, Michael C.; Hammons, Kevin R.

    1988-01-01

    Enhancements to the real-time processing and display systems of the NASA Western Aeronautical Test Range are described. Display processing has been moved out of the telemetry and radar acquisition processing systems super-minicomputers into user/client interactive graphic workstations. Real-time data is provided to the workstations by way of Ethernet. Future enhancement plans include use of fiber optic cable to replace the Ethernet.

  15. Gas exchange and intrapulmonary distribution of ventilation during continuous-flow ventilation

    SciTech Connect

    Vettermann, J.; Brusasco, V.; Rehder, K.

    1988-05-01

    In 12 anesthetized paralyzed dogs, pulmonary gas exchange and intrapulmonary inspired gas distribution were compared between continuous-flow ventilation (CFV) and conventional mechanical ventilation (CMV). Nine dogs were studied while they were lying supine, and three dogs were studied while they were lying prone. A single-lumen catheter for tracheal insufflation and a double-lumen catheter for bilateral endobronchial insufflation (inspired O2 fraction = 0.4; inspired minute ventilation = 1.7 +/- 0.3 (SD) 1.kg-1.min-1) were evaluated. Intrapulmonary gas distribution was assessed from regional 133Xe clearances. In dogs lying supine, CO2 elimination was more efficient with endobronchial insufflation than with tracheal insufflation, but the alveolar-arterial O2 partial pressure difference was larger during CFV than during CMV, regardless of the type of insufflation. By contrast, endobronchial insufflation maintained both arterial PCO2 and alveolar-arterial O2 partial pressure difference at significantly lower levels in dogs lying prone than in dogs lying supine. In dogs lying supine, the dependent lung was preferentially ventilated during CMV but not during CFV. In dogs lying prone, gas distribution was uniform with both modes of ventilation. The alveolar-arterial O2 partial pressure difference during CFV in dogs lying supine was negatively correlated with the reduced ventilation of the dependent lung, which suggests that increased ventilation-perfusion mismatching was responsible for the increase in alveolar-arterial O2 partial pressure difference. The more efficient oxygenation during CFV in dogs lying prone suggests a more efficient matching of ventilation to perfusion, presumably because the distribution of blood flow is also nearly uniform.

  16. Field testing the role of heterogeneity at the inter-well scale during two phase flow

    NASA Astrophysics Data System (ADS)

    Hovorka, S. D.; Gulf Coast Carbon Center; Geoseq

    2011-12-01

    Connectivity of rocks with different fluid flow properties (reservoir architecture) is a major source of uncertainty in predicting multi-phase fluid flow. Multi-institution research teams have completed three major DOE-funded test programs in which movement of supercritical CO2 through brine-saturated fluvial sandstones was observed with multiple tools. In each test, closely spaced wells (30 to 100 m) were drilled to reservoir depth so that the amount of reservoir complexity sampled between the wells would be reduced and higher resolution measurements of change could be obtained during time-lapse monitoring. During one test (Frio 1), an exceptionally homogeneous injection zone produced by marine reworking of a fine-grained fluvial sandstone of the Upper Frio Formation produced a classic-wedge-shaped CO2 plume. The maximum area occupied by CO2 was the result of radial expansion of the plume near the injection well; this produced plume down-building. Away from the injection well , the importance of gravity-override increased. A second test at the same well array in a deeper sandstone (Frio 2) was sited in heterogeneous (gravel to muddy sandstone) high permeability (>3 Darcy), weakly cemented fluvial sandstone. A slow injection rate over a small interval at the flow unit base was used to accentuate buoyancy effects. Measurements of plume migration through time using tracers and cross-well seismic documented interaction between near-well radial flow and vertical rise. However, because of discontinuous fast paths in gravel zones and CO2 ponding against muddy sandstone baffles, reservoir heterogeneity was a dominant influence in short-term plume evolution. The third test interval in the SECARB "Early" test documented response of amalgamated gravel and sandstone point bars in which heterogeneity was reduced by cementation. CO2 injection rate was increased incrementally and flow-rate dependent reservoir responses observed. These suggest that capillary-entry pressure and

  17. Heat-transfer distributions on biconics at incidence in hypersonic-hypervelocity He, N2, air, and CO2 flows

    NASA Technical Reports Server (NTRS)

    Miller, C. G.; Micol, J. R.; Gnoffo, P. A.; Wilder, S. E.

    1983-01-01

    Laminar heat transfer rates were measured on spherically blunted, 13 deg/7 deg on axis and bent biconics (fore cone bent 7 deg upward relative to aft cone) at hypersonic hypervelocity flow conditions in the Langley Expansion Tube. Freestream velocities from 4.5 to 6.9 km/sec and Mach numbers from 6 to 9 were generated using helium, nitrogen, air, and carbon dioxide test gases, resulting in normal shock density ratios from 4 to 19. Angle of attack, referenced to the axis of the aft cone, was varied from 0 to 20 deg in 4 deg increments. The effect of nose bend, angle of attack, and real gas phenomena on heating distributions are presented along with comparisons of measurement to prediction from a code which solves the three dimensional parabolized Navier-Stokes equations.

  18. A Mathematical Model of Gas Flow Distribution in the Grate-Kiln Iron Ore Pellets Induration Process

    NASA Astrophysics Data System (ADS)

    Feng, Junxiao; Zhang, Yu; Zhang, Yiyang; Xie, Zhiyin; Zhang, Cai

    2010-03-01

    Although models for general gas (e.g. natural gas) pipeline networks have been well established, research on another kind of gas networks we named gas passage networks (i.e. GPN; set that gas pass through spaces) in industry is rare. The features of the GPN are hard-determination leakage (i.e. 24.4%), quite-different thermophysical-properties, more cycles and not engaging cycle energy equations directly. And the gas network of grate-kiln-cooler (GKC) plant used for iron ore pellets induration is belong to this type. This paper develops a mathematical model to evaluate the flow distribution in this kind. Further, a field test was systematically carried out on a GKC plant in China. At last, the result shows that good agreement was observed, indicating the validity of the model.

  19. Unscheduled load flow effect due to large variation in the distributed generation in a subtransmission network

    NASA Astrophysics Data System (ADS)

    Islam, Mujahidul

    A sustainable energy delivery infrastructure implies the safe and reliable accommodation of large scale penetration of renewable sources in the power grid. In this dissertation it is assumed there will be no significant change in the power transmission and distribution structure currently in place; except in the operating strategy and regulatory policy. That is to say, with the same old structure, the path towards unveiling a high penetration of switching power converters in the power system will be challenging. Some of the dimensions of this challenge are power quality degradation, frequent false trips due to power system imbalance, and losses due to a large neutral current. The ultimate result is the reduced life of many power distribution components - transformers, switches and sophisticated loads. Numerous ancillary services are being developed and offered by the utility operators to mitigate these problems. These services will likely raise the system's operational cost, not only from the utility operators' end, but also reflected on the Independent System Operators and by the Regional Transmission Operators (RTO) due to an unforeseen backlash of frequent variation in the load-side generation or distributed generation. The North American transmission grid is an interconnected system similar to a large electrical circuit. This circuit was not planned but designed over 100 years. The natural laws of physics govern the power flow among loads and generators except where control mechanisms are installed. The control mechanism has not matured enough to withstand the high penetration of variable generators at uncontrolled distribution ends. Unlike a radial distribution system, mesh or loop networks can alleviate complex channels for real and reactive power flow. Significant variation in real power injection and absorption on the distribution side can emerge as a bias signal on the routing reactive power in some physical links or channels that are not distinguishable

  20. Use of artificial and natural tracers to assess groundwater transit-time distribution and flow systems in a high-alpine karst system (Wetterstein Mountains, Germany)

    NASA Astrophysics Data System (ADS)

    Lauber, Ute; Goldscheider, Nico

    2014-12-01

    Groundwater in mountainous karst regions is vital for regional water budgets and freshwater supply. Owing to increasing water demand and climate change, detailed knowledge of the highly heterogeneous alpine aquifer systems is required. Multi-tracer analyses have been conducted in the steep karstic Wetterstein Mountains, which includes Germany's highest summit, Zugspitze (2,962 m asl). Results of artificial tracer tests demonstrate well-developed flow paths through the unsaturated zone (up to 1,000 m thickness). Flow paths cross topographic divides and contribute to deep drainage systems underneath alpine valleys. Cross-formational flow has been identified. Quantitative analysis of tailing-dominated breakthrough curves and stable isotopes (18O) has enabled determination of the mean transit-time distribution. A fast-flow component with transit times between 3 and 13 days was found in karst conduits and open fissures, dependent on flow conditions. An intermediate-flow component, showing mean transit times of about 2.9-4.9 months, was found in well-drained fissures and fractures. A slow-flow component with mean transit times greater than 1 year is attributable to slow flow and low storage in the poorly drained fissures and rock matrix. The conceptual model enables a better understanding of drainage, water resources and vulnerability of the high-alpine karst system.