Sample records for plunging liquid jet

  1. Air entrainment by a plunging liquid jet on a liquid pool

    Microsoft Academic Search

    Amable Liñan; Juan C. Lasheras

    1999-01-01

    When a liquid jet impinges on liquid pool, with a velocity higher than a critical velocity, a thin air film is entrained by the jet. The thickness ha of the air film, and thus the air mass entrained by the jet, is a function of its radius a and velocity U. This function, for the realistic small values of the

  2. Low-frequency acoustic emissions of a plunging water jet

    Microsoft Academic Search

    Thomas R. Hahn

    1999-01-01

    Low-frequency acoustic emissions of bubble clouds entrained and dispersed by continuous, steady and transient, fresh water jets were studied both theoretically and experimentally for various jet velocities and entrainment rates. A continuous plunging liquid jet impinging on a free liquid surface entrains air and produces a bubble cloud with a statistically well-defined geometry. At low frequencies the resulting bubble cloud

  3. Laminar Plunging Jets - Interfacial Rupture and Inception of Entrainment

    NASA Astrophysics Data System (ADS)

    Kishore, Aravind

    Interfacial rupture and entrainment are commonly observed, e.g., air bubbles within a container being filled with water from a faucet. The example involves a liquid jet (density, rho, and viscosity, ?) plunging into a receiving pool of liquid. Below a critical liquid-jet velocity, the interface develops a cusp-like shape within the receiving pool. The cusp becomes sharper with increasing liquid-jet velocity, and at a critical velocity ( Vc), the interface between the liquid and the surrounding fluid (density, rho0, and viscosity, ?0) ruptures. Interfacial tension (sigma) can no longer preserve the integrity of the interface between the two immiscible fluids, and the plunging jet drags/entrains surrounding fluid into the receiving pool. Subsequently, the entrained fluid breaks up into bubbles within the receiving pool. The focus of this dissertation is the numerical prediction of the critical entrainment inception velocities for laminar plunging jets using the Volume-Of-Fluid (VOF) method, a Computational Fluid Dynamics (CFD) method to simulate multi-fluid flows. Canonical to bottle-filling operations in the industry is the plunging-jet configuration -- the liquid jet issues from a nozzle and plunges into a container filled with liquid. Simulations of this configuration require capturing flow phenomena over a large range of length scales (4 orders of magnitude). Results show severe under-prediction of critical entrainment velocities when the maximum resolution is insufficient to capture the sharpening, and eventual rupture, of the interfacial cusp. Higher resolutions resulted in computational meshes with prohibitively large number of cells, and a drastic reduction in time-step values. Experimental results in the literature suggest at least a 100-fold increase in the smallest length scale when the entrained fluid is a liquid instead of air. This narrows the range of length scales in the problem. We exploit the experimental correlation between critical capillary number, Cac = ??Vc/sigma and viscosity ratio, ?0/? in postulating an alternate approach involving scaling of the pertinent physics by using liquids as entrained fluids. The scaling approach is tested using a rotating cylinder placed at the interface between two fluids. A mesh-independence study using successively finer meshes predicted critical entrainment velocity values within about 1% of each other. Numerical predictions compared well with experimental data, with less than 1% difference in the case where exact experimental data was available, and a maximum of 6% difference for cases where experimental data was extrapolated to make the comparison. These results lend credibility to our approach. The effect of densities of the two fluids manifests as buoyancy force at the interfacial cusp. Remarkably, contrary to a priori notions, our simulation results showed that as Deltarho increased, the effect of buoyancy decreased relative to other forces at the interfacial cusp. Finally, we proposed an empirical correlation between Cac and ? 0/? which allows extrapolation of critical entrainment conditions between the rotating-cylinder configuration (with liquids being entrained) to the plunging-jet configuration (with air being entrained). The primary contribution of this research is the physics-based scaling approach utilized to overcome the simulation challenges posed by the physics of interface rupture and entrainment.

  4. On the Jet Impact in a Plunging Breaker

    NASA Astrophysics Data System (ADS)

    Shakeri, M.; Tavakolinejad, M.; Maxeiner, E. A.; Duncan, J. H.

    2007-11-01

    Plunging breaking ship bow waves were simulated experimentally using a 2D+T wave maker in a tank that is 14.8 m long, 1.15 m wide and 2.1 m deep (water depth of 1.83 m). In the 2D+T simulation, the sequence of shapes of the flexible surface (wave board) of the wave maker reproduces the time varying intersection of one side of the ship hull with a vertical plane oriented normal to the ship's track as the ship moves in calm water at constant speed. For equivalent full-scale ship speeds greater than about 20 knots, a large plunging breaker is formed. An LIF system that employs a high-speed digital movie camera taking pictures at 256 frames per second was used to measure the temporal history of the profile of the plunging jet. In each image, the top surface of the jet is easily extracted as the intersection of the light sheet with the water surface. The bottom surface of the jet is also seen in the images, but since it is seen by looking through the jet, its profile must be obtained by using an inverse refraction method. The characteristics of the jet including the velocity and acceleration of the jet tip and the distribution of jet thickness are presented. It is interesting to note that the jet tip trajectory is ballistic, but that the vertical acceleration ranges from about 0.6 to 0.8 times the acceleration of gravity.

  5. Plunging cylinder liquid piston Stirling engine

    SciTech Connect

    Tailer, P.L.; West, J.H.

    1987-06-30

    A Stirling engine is described comprising, in combination, cylinders having tops and open lower ends, tanks containing hot and cold fluid, with a means plunging the cylinders out of phase into the hot and cold fluid. There is at least one connecting tube providing a passage between the upper portions of the cylinders. A working gas provided in the upper portion of the cylinders and the connecting tube.

  6. Air Entrainment by a Viscous Jet Plunging into a Bath Elise Lorenceau and David Quere

    E-print Network

    Eggers, Jens

    Ca V= . Any increase in jet velocity leads to a large decrease of the radius of curvature at the tip exerts a lubrication pressure on it. Below a critical tip radius (thus above a critical jet velocityAir Entrainment by a Viscous Jet Plunging into a Bath E´lise Lorenceau and David Que´re´ Physique

  7. The hydraulic bump: The surface signature of a plunging jet M. Labousse and J. W. M. Bush

    E-print Network

    The hydraulic bump: The surface signature of a plunging jet M. Labousse and J. W. M. Bush Citation://pof.aip.org/authors #12;PHYSICS OF FLUIDS 25, 094104 (2013) The hydraulic bump: The surface signature of a plunging jet M a falling jet of fluid strikes a horizontal fluid layer, a hydraulic jump arises downstream of the point

  8. FIELD MANUAL FOR PLUNGING WATER JET USE IN OIL SPILL CLEANUP

    EPA Science Inventory

    The use of plunging water jets can often make possible the control (and, as a consequence, the cleanup) of spilled oil and other floating pollutants in currents too swift for conventional equipment. This short, illustrated manual provides practical information for field and plann...

  9. The hydraulic bump: The surface signature of a plunging jet

    E-print Network

    Labousse, M.

    When a falling jet of fluid strikes a horizontal fluid layer, a hydraulic jump arises downstream of the point of impact, provided a critical flow rate is exceeded. We here examine a phenomenon that arises below this jump ...

  10. On the seawater temperature dependence of the sea spray aerosol generated by a continuous plunging jet

    NASA Astrophysics Data System (ADS)

    Salter, M. E.; Nilsson, E. D.; Butcher, A.; Bilde, M.

    2014-07-01

    Breaking waves on the ocean surface produce bubbles which, upon bursting, deliver seawater constituents into the atmosphere as sea spray aerosol particles. One way of investigating this process in the laboratory is to generate a bubble plume by a continuous plunging jet. We performed a series of laboratory experiments to elucidate the role of seawater temperature on aerosol production from artificial seawater free from organic contamination using a plunging jet. The seawater temperature was varied from -1.3°C to 30.1°C, while the volume of air entrained by the jet, surface bubble size distributions, and size distribution of the aerosol particles produced was monitored. We observed that the volume of air entrained decreased as the seawater temperature was increased. The number of surface bubbles with film radius smaller than 2 mm decreased nonlinearly with seawater temperature. This decrease was coincident with a substantial reduction in particle production. The number concentrations of particles with dry diameter less than ˜1 ?m decreased substantially as the seawater temperature was increased from -1.3°C to ˜9°C. With further increase in seawater temperature (up to 30°C), a small increase in the number concentration of larger particles (dry diameter >˜0.3 ?m) was observed. Based on these observations, we infer that as seawater temperature increases, the process of bubble fragmentation changes, resulting in decreased air entrainment by the plunging jet, as well as the number of bubbles with film radius smaller than 2 mm. This again results in decreased particle production with increasing seawater temperature.

  11. Determination of heat transfer coefficients in plastic French straws plunged in liquid nitrogen.

    PubMed

    Santos, M Victoria; Sansinena, M; Chirife, J; Zaritzky, N

    2014-12-01

    The knowledge of the thermodynamic process during the cooling of reproductive biological systems is important to assess and optimize the cryopreservation procedures. The time-temperature curve of a sample immersed in liquid nitrogen enables the calculation of cooling rates and helps to determine whether it is vitrified or undergoes phase change transition. When dealing with cryogenic liquids, the temperature difference between the solid and the sample is high enough to cause boiling of the liquid, and the sample can undergo different regimes such as film and/or nucleate pool boiling. In the present work, the surface heat transfer coefficients (h) for plastic French straws plunged in liquid nitrogen were determined using the measurement of time-temperature curves. When straws filled with ice were used the cooling curve showed an abrupt slope change which was attributed to the transition of film into nucleate pool boiling regime. The h value that fitted each stage of the cooling process was calculated using a numerical finite element program that solves the heat transfer partial differential equation under transient conditions. In the cooling process corresponding to film boiling regime, the h that best fitted experimental results was h=148.12±5.4 W/m(2) K and for nucleate-boiling h=1355±51 W/m(2) K. These values were further validated by predicting the time-temperature curve for French straws filled with a biological fluid system (bovine semen-extender) which undergoes freezing. Good agreement was obtained between the experimental and predicted temperature profiles, further confirming the accuracy of the h values previously determined for the ice-filled straw. These coefficients were corroborated using literature correlations. The determination of the boiling regimes that govern the cooling process when plunging straws in liquid nitrogen constitutes an important issue when trying to optimize cryopreservation procedures. Furthermore, this information can lead to improvements in the design of cooling devices in the cryobiology field. PMID:25445573

  12. Bouncing of a Jet off a Newtonian Liquid Surface

    NASA Astrophysics Data System (ADS)

    Thrasher, Matthew; Jung, Sunghwan; Swinney, Harry L.

    2006-11-01

    A viscous liquid stream plunging toward a horizontally moving bath of the same liquid can bounce off the surface without mixing with the bath's fluid. A thin layer of air separates the jet and the bath. The non-coalescing jet ramps off an indentation that it makes in the bath's surface. The jet then moves in a roughly parabolic flight until it hits the translating surface again, where it may bounce a second time. Similar rebounding phenomena, such as the Kaye effect, have been observed in non-Newtonian fluids. However, we report the first observations of a bouncing Newtonian liquid jet. We observe the bouncing jet for many different liquids, including silicone oil. The bouncing jet is stable for a large range of parameters, including the oil's viscosity (50 to 520 mPa s), the jet's radius (0.05 to 0.12 cm), the jet's velocity at impact (40 to 170 cm/s, corresponding to nozzle heights 1.7 to 14 cm), and the bath's horizontal velocity (1 to 35 cm/s). The bouncing jet involves an interplay of viscous, inertial, surface, and gravitational forces. By initiating the jet in different ways, up to four stable configurations have been observed for the same experimental conditions. A video entry into the Gallery of Fluid Motion features this research.

  13. Measurement of the Bubbles Entrained in a Translating Axisymmetric Plunging Laminar Jet

    NASA Astrophysics Data System (ADS)

    Tavakolinejad, M.; Shakeri, M.; Chang, P.; Duncan, J. H.

    2006-11-01

    Air entrainment induced by a translating axisymmetric laminar vertical water jet as it impinges onto the free surface of a quiescent pool of water is studied experimentally. The experiments are performed in a towing tank that is 24 ft long, 2.5 ft wide and 3 ft deep. When the jet is stationary, the water surface around the jet impact site is smooth and no air is entrained. When the jet is moving horizontally, a depression of the free surface forms directly downstream of the jet. Air is entrained from the cusp formed at the bottom of the leading edge of the depression. Previously presented high-speed flow visualization movies of the entrainment process have show that the bubbles enter the water when vortices from the jet shear layer pass over the cusp and that these bubbles are initially trapped within the vortices. Further downstream, two regions of bubbles are formed. Close behind the jet and near the free surface there is a region of large irregular shaped bubbles with relatively high rise velocity. Deeper in the water and extending further downstream there is a region of small diameter bubbles with lower rise velocity. The results of shadowgraph measurements of the size distributions of the small bubbles in fresh and salt water are presented. In the presence of salt water, a larger number of small diameter bubbles is found.

  14. A study of liquid jets

    Microsoft Academic Search

    G. Klingenberg; J. D. Knapton; K. E. Travis

    1982-01-01

    Various correlations were examined that were used for predicting mean droplet sizes generated by a single fluid jet. The correlation was compared with semiquantitative data obtained from spark photographs and from a particle sizing interferometer. Jet properties were investigated for three types of fluids, i.e., water, Hexane, and a moderately energetic liquid monopropellant (LP) used in gun applications. The photographic

  15. Whipping of electrified liquid jets.

    PubMed

    Guerrero, Josefa; Rivero, Javier; Gundabala, Venkata R; Perez-Saborid, Miguel; Fernandez-Nieves, Alberto

    2014-09-23

    We apply an electric field to a moderately conducting liquid surrounded by another coflowing liquid, all inside a glass-based microfluidic device, to study nonaxisymmetric instabilities. We find that the bending of the electrified jet results in a steady-state, helicoidal structure with a constant opening angle. Remarkably, the characteristic phase speed of the helicoidal wave only depends on the charge carried by the jet in the helicoidal region and its stability critically depends on the properties of the coflowing liquid. In fact, the steady-state helical structure becomes chaotic when the longest characteristic time is that of the inner liquid rather than that of the outer coflowing liquid. We also perform a numerical analysis to show that the natural preference of the jet is to adopt the conical helix structure observed experimentally. PMID:25201984

  16. A study of liquid jets

    NASA Astrophysics Data System (ADS)

    Klingenberg, G.; Knapton, J. D.; Travis, K. E.

    1982-10-01

    Various correlations were examined that were used for predicting mean droplet sizes generated by a single fluid jet. The correlation was compared with semiquantitative data obtained from spark photographs and from a particle sizing interferometer. Jet properties were investigated for three types of fluids, i.e., water, Hexane, and a moderately energetic liquid monopropellant (LP) used in gun applications. The photographic data are only suitable for a semiquantitative analysis due to severe diffraction problems. Some preliminary low velocity droplet data were obtained with the particle sizing interferometer.

  17. A new classification for liquid jets dynamics

    NASA Astrophysics Data System (ADS)

    Ling, Bowen; Battiato, Ilenia

    2013-11-01

    The physics of liquid jets has been attracting scientists' interest for many decades. Previous works have focused on various aspects of jets dynamics including instability, self-similarity, etc. We propose a new criterion to classify liquid jets dynamics based on a non-dimensionalization of Navier-Stokes equations, which generalises well-established scalings. We employ such framework to describe specific dynamics, e.g. breakup characteristics, drop formation and dripping-jetting transition, and identify the driving physical mechanisms of different regimes. We compare the proposed classification with experimental results.

  18. Droplet formation for liquid monopropellant jets

    NASA Astrophysics Data System (ADS)

    Macken, Nelson A.

    1987-02-01

    The hydrodynamic development of droplets for conditions approximating those in the combustion chamber of regenerative liquid propellant guns has been investigated. The report contains a literature survey and discussion of various breakup mechanisms. Aerodynamic interaction is analyzed using classical stability theory and a formulation applied to anticipated working conditions. The model predicts mass removed and droplet size as a function of time. Results indicate that the jet does break up with almost all liquid atomized. Comparison to a simple burning rate model verifies that the hydrodynamic model is primarily responsible for liquid removal from the intact core. Results conflict with recent inverse gun code predictions which suggest significant liquid accumulation is occurring; i.e., the jet does not fully atomize and subsequently burn. A discussion of possible reasons for this discrepancy is included.

  19. Single-Phase Liquid Jet Impingement Heat Transfer

    Microsoft Academic Search

    C.-F. Ma

    1995-01-01

    Impinging liquid jets have been demonstrated to be an effective means of providing high heat\\/mass transfer rates in industrial transport processes. When a liquid jet strikes a surface, thin hydrodynamic and thermal boundary layers from in the region directly beneath due to the jet deceleration and the resulting increase in pressure. The flow is then forced to accelerate in a

  20. Compound liquid jets at low Reynolds numbers

    Microsoft Academic Search

    J. I Ramos

    2002-01-01

    Asymptotic methods based on the slenderness ratio are used to obtain the leading-order equations which govern the fluid dynamics of axisymmetric, isothermal, Newtonian, compound liquid jets such as those employed in the manufacture of textile fibres, composite fibres and optical fibres, at low Reynolds numbers. It is shown that the leading-order equations are one-dimensional, and analytical solutions are obtained for

  1. Size limits the formation of liquid jets during bubble bursting.

    PubMed

    Lee, Ji San; Weon, Byung Mook; Park, Su Ji; Je, Jung Ho; Fezzaa, Kamel; Lee, Wah-Keat

    2011-01-01

    A bubble reaching an air-liquid interface usually bursts and forms a liquid jet. Jetting is relevant to climate and health as it is a source of aerosol droplets from breaking waves. Jetting has been observed for large bubbles with radii of R?100??m. However, few studies have been devoted to small bubbles (R<100??m) despite the entrainment of a large number of such bubbles in sea water. Here we show that jet formation is inhibited by bubble size; a jet is not formed during bursting for bubbles smaller than a critical size. Using ultrafast X-ray and optical imaging methods, we build a phase diagram for jetting and the absence of jetting. Our results demonstrate that jetting in bubble bursting is analogous to pinching-off in liquid coalescence. The coalescence mechanism for bubble bursting may be useful in preventing jet formation in industry and improving climate models concerning aerosol production. PMID:21694715

  2. Flow visualization of high-speed pulsed-liquid jet

    Microsoft Academic Search

    Xiao-Liang Wang; Hong-Hui Shi; Motoyuki Itoh; Masami Kishimoto

    2001-01-01

    This paper describes a flow visualization of high-speed liquid jets ranging from 20 m\\/s to 200 m\\/s, which were generated from two different methods. The first method is that the jet (200 m\\/s) is generated by using a high-speed projectile to impact a rectangular nozzle where water is contained. For the 200 m\\/s liquid jets, flow visualization was conducted using

  3. Generation of hypersonic liquid fuel jets accompanying self-combustion

    Microsoft Academic Search

    Hong-Hui Shi; Kazuyoshi Takayama

    1999-01-01

    .   Aerodynamic behavior of pulsed hypersonic light oil jets injected at 2 km\\/s and 3 km\\/s is presented. Auto-ignition and combustion\\u000a of the fuel during the injection process were visualized. The combustion around the disintegrating jet was enhanced by liquid\\u000a atomization created by the very high injection pressure as well as the interfacial instability of the hypersonic jet. The\\u000a jets

  4. Turbulent noncondensing and condensing gas jets in liquids

    NASA Astrophysics Data System (ADS)

    Sun, T. Y.; Chuech, S. G.; Parthasarathy, R. N.; Faeth, G. M.

    1985-08-01

    Gas injection into liquids is a fundamental multiphase flow which has several direct applications, e.g., stored chemical energy propulsion systems (SCEPS), direct-contact condensers, gas dissolution systems, reservoir destratification systems and nuclear-reactor pressure suppression systems. Stability of these flow is enhanced when an underexpanded jet is used; therefore, the interaction of supersonic wave structures with liquids in turbulent flow is also an issue. The objective of this phase of the study was to develop test apparatus relating to underexpanded air jets in air and turbulent subsonic gas jets in liquids. The air-jet-in-air apparatus was assembled and flow visualization tests were completed using continuous and spark Schlieren photography. Test apparatus for gas injection in liquids was assembled. Tests were also undertaken to study injector stability. Test results showed that jet instability for subsonic (adapted) flow could be controlled by placing a screen across the jet exit and controlling gas release at the surface or the bath (which can cause undesirable pressure fluctuations in the bath). For stable jets, the liquid/gas interface is continous near the jet exit and its position is influenced by the degree of underexpansion. A bubble cloud was observed near the interface, and it is also probable that a drop cloud in present as well. Analysis of this flow for subsonic jet exit conditions was implemented using the locally homogeneous flow approximation of multiphase flow.

  5. Bouncing jet: a Newtonian liquid rebounding off a free surface.

    PubMed

    Thrasher, Matthew; Jung, Sunghwan; Pang, Yee Kwong; Chuu, Chih-Piao; Swinney, Harry L

    2007-11-01

    We find that a liquid jet can bounce off a bath of the same liquid if the bath is moving horizontally with respect to the jet. Previous observations of jets rebounding off a bath (e.g., the Kaye effect) have been reported only for non-Newtonian fluids, while we observe bouncing jets in a variety of Newtonian fluids, including mineral oil poured by hand. A thin layer of air separates the bouncing jet from the bath, and the relative motion replenishes the film of air. Jets with one or two bounces are stable for a range of viscosity, jet flow rate and velocity, and bath velocity. The bouncing phenomenon exhibits hysteresis and multiple steady states. PMID:18233768

  6. Multiphase flow of miscible liquids: jets and drops

    NASA Astrophysics Data System (ADS)

    Walker, Travis W.; Logia, Alison N.; Fuller, Gerald G.

    2015-05-01

    Drops and jets of liquids that are miscible with the surrounding bulk liquid are present in many processes from cleaning surfaces with the aid of liquid soaps to the creation of biocompatible implants for drug delivery. Although the interactions of immiscible drops and jets show similarities to miscible systems, the small, transient interfacial tension associated with miscible systems create distinct outcomes such as intricate droplet shapes and breakup resistant jets. Experiments have been conducted to understand several basic multiphase flow problems involving miscible liquids. Using high-speed imaging of the morphological evolution of the flows, we have been able to show that these processes are controlled by interfacial tensions. Further multiphase flows include investigating miscible jets, which allow the creation of fibers from inelastic materials that are otherwise difficult to process due to capillary breakup. This work shows that stabilization from the diminishing interfacial tensions of the miscible jets allows various elongated morphologies to be formed.

  7. Analysis of interaction phenomena between liquid jets and materials

    SciTech Connect

    Kang, Sang-Wook; Reitter, T.; Carlson, G.

    1995-02-01

    The interaction phenomena of high-velocity liquid jets impinging on a material surface have been investigated theoretically and experimentally to gain an understanding of the physical mechanisms involved in material removal by fluidjet machining processes. Experiments were performed to determine conditions under which the liquid jet impacting a solid material will cause material removal and also to delineate possible physical mechanisms of mass removal at optimum jet-cutting conditions. We have also carried out numerical simulations of jet-induced surface pressure rises and of the material deformation and spallation behavior due to multiple droplet impacts. Results obtained from the experiments and theoretical calculations and their physical implications are also discussed.

  8. Controls on Filling and Evacuation of Sediment in Waterfall Plunge Pools

    NASA Astrophysics Data System (ADS)

    Scheingross, J. S.; Lamb, M. P.

    2014-12-01

    Many waterfalls are characterized by the presence of deep plunge pools that experience periods of sediment fill and evacuation. These cycles of sediment fill are a first order control on the relative magnitude of lateral versus vertical erosion at the base of waterfalls, as vertical incision requires cover-free plunge pools to expose the bedrock floor, while lateral erosion can occur when pools are partially filled and plunge-pool walls are exposed. Currently, there exists no mechanistic model describing sediment transport through waterfall plunge pools, limiting our ability to predict waterfall retreat. To address this knowledge gap, we performed detailed laboratory experiments measuring plunge-pool sediment transport capacity (Qsc_pool) under varying waterfall and plunge-pool geometries, flow hydraulics, and sediment size. Our experimental plunge-pool sediment transport capacity measurements match well with a mechanistic model we developed which combines existing waterfall jet theory with a modified Rouse profile to predict sediment transport capacity as a function of water discharge and suspended sediment concentration at the plunge-pool lip. Comparing the transport capacity of plunge pools to lower gradient portions of rivers (Qsc_river) shows that, for transport limited conditions, plunge pools fill with sediment under modest water discharges when Qsc_river > Qsc_pool, and empty to bedrock under high discharges when Qsc_pool > Qsc_river. These results are consistent with field observations of sand-filled plunge pools with downstream boulder rims, implying filling and excavation of plunge pools over single-storm timescales. Thus, partial filling of waterfall plunge pools may provide a mechanism to promote lateral undercutting and retreat of waterfalls in homogeneous rock in which plunge-pool vertical incision occurs during brief large floods that expose bedrock, whereas lateral erosion may prevail during smaller events.

  9. Modeling of turbulence effect on liquid jet atomization

    Microsoft Academic Search

    Huu Phuoc Trinh

    2004-01-01

    Recent experimental investigations and physical modeling studies have indicated that turbulence behaviors within a liquid jet have considerable effects on the atomization process. Such turbulent flow phenomena are encountered in most practical applications of common liquid spray devices. Most existing atomization models do not account for the turbulence effects. Only limited attempts have been made to model the subject effects

  10. Impinging jet separators for liquid metal magnetohydrodynamic power cycles

    NASA Technical Reports Server (NTRS)

    Bogdanoff, D. W.

    1973-01-01

    In many liquid metal MHD power, cycles, it is necessary to separate the phases of a high-speed liquid-gas flow. The usual method is to impinge the jet at a glancing angle against a solid surface. These surface separators achieve good separation of the two phases at a cost of a large velocity loss due to friction at the separator surface. This report deals with attempts to greatly reduce the friction loss by impinging two jets against each other. In the crude impinging jet separators tested to date, friction losses were greatly reduced, but the separation of the two phases was found to be much poorer than that achievable with surface separators. Analyses are presented which show many lines of attack (mainly changes in separator geometry) which should yield much better separation for impinging jet separators).

  11. Modeling of Turbulence Effect on Liquid Jet Atomization

    NASA Technical Reports Server (NTRS)

    Trinh, H. P.

    2007-01-01

    Recent studies indicate that turbulence behaviors within a liquid jet have considerable effect on the atomization process. Such turbulent flow phenomena are encountered in most practical applications of common liquid spray devices. This research aims to model the effects of turbulence occurring inside a cylindrical liquid jet to its atomization process. The two widely used atomization models Kelvin-Helmholtz (KH) instability of Reitz and the Taylor analogy breakup (TAB) of O'Rourke and Amsden portraying primary liquid jet disintegration and secondary droplet breakup, respectively, are examined. Additional terms are formulated and appropriately implemented into these two models to account for the turbulence effect. Results for the flow conditions examined in this study indicate that the turbulence terms are significant in comparison with other terms in the models. In the primary breakup regime, the turbulent liquid jet tends to break up into large drops while its intact core is slightly shorter than those without turbulence. In contrast, the secondary droplet breakup with the inside liquid turbulence consideration produces smaller drops. Computational results indicate that the proposed models provide predictions that agree reasonably well with available measured data.

  12. Experimental investigation of charged liquid jet efflux from a capillary

    NASA Astrophysics Data System (ADS)

    Zhakin, A. I.; Belov, P. A.; Kuz'ko, A. E.

    2013-03-01

    The shapes and electrical characteristics of charged liquid (water, ethanol, glycerol, castor oil) jets emitted from a metal capillary have been experimentally studied depending on the applied high voltage. A map of efflux regimes in the flow velocity-applied voltage coordinates is constructed for water. The effects of medium viscosity, surface tension, and charge relaxation time on the laws of jet efflux are analyzed.

  13. Transverse liquid fuel jet breakup, burning, and ignition

    SciTech Connect

    Li, H.

    1990-12-31

    An analytical/numerical study of the breakup, burning, and ignition of liquid fuels injected transversely into a hot air stream is conducted. The non-reacting liquid jet breakup location is determined by the local sonic point criterion first proposed by Schetz, et al. (1980). Two models, one employing analysis of an elliptical jet cross-section and the other employing a two-dimensional blunt body to represent the transverse jet, have been used for sonic point calculations. An auxiliary criterion based on surface tension stability is used as a separate means of determining the breakup location. For the reacting liquid jet problem, a diffusion flame supported by a one-step chemical reaction within the gaseous boundary layer is solved along the ellipse surface in subsonic crossflow. Typical flame structures and concentration profiles have been calculated for various locations along the jet cross-section as a function of upstream Mach numbers. The integrated reaction rate along the jet cross-section is used to predict ignition position, which is found to be situated near the stagnation point. While a multi-step reaction is needed to represent the ignition process more accurately, the present calculation does yield reasonable predictions concerning ignition along a curved surface.

  14. Combined aerodynamic and electrostatic atomization of dielectric liquid jets

    NASA Astrophysics Data System (ADS)

    Kourmatzis, Agissilaos; Ergene, Egemen L.; Shrimpton, John S.; Kyritsis, Dimitrios C.; Mashayek, Farzad; Huo, Ming

    2012-07-01

    The electrical and atomization performance of a plane-plane charge injection atomizer using a dielectric liquid, and operating at pump pressures ranging from 15 to 35 bar corresponding to injection velocities of up to 50 m/s, is explored via low current electrical measurements, spray imaging and phase Doppler anemometry. The work is aimed at understanding the contribution of electrostatic charging relevant to typical higher pressure fuel injection systems such as those employed in the aeronautical, automotive and marine sectors. Results show that mean-specific charge increases with injection velocity significantly. The effect of electrostatic charge is advantageous at the 15-35 bar range, and an arithmetic mean diameter D 10 as low as 0.2 d is achievable in the spray core and lower still in the periphery where d is the orifice diameter. Using the data available from this higher pressure system and from previous high Reynolds number systems (Shrimpton and Yule Exp Fluids 26:460-469, 1999), the promotion of primary atomization has been analysed by examining the effect that charge has on liquid jet surface and liquid jet bulk instability. The results suggest that for the low charge density Q v ~ 2 C/m3 cases under consideration here, a significant increase in primary atomization is observed due to a combination of electrical and aerodynamic forces acting on the jet surface, attributed to the significantly higher jet Weber number ( We j) when compared to low injection pressure cases. Analysis of Sauter mean diameter results shows that for jets with elevated specific charge density of the order Q v ~ 6 C/m3, the jet creates droplets that a conventional turbulent jet would, but with a significantly lower power requirement. This suggests that `turbulent' primary atomization, the turbulence being induced by electrical forces, may be achieved under injection pressures that would produce laminar jets.

  15. Whipping charged jet instabilities within dielectric liquid baths

    NASA Astrophysics Data System (ADS)

    Riboux, Guillaume; Marin, Alvaro G.; Loscertales, Ignacio G.; Barrero, Antonio

    2008-11-01

    Capillary liquid flows have shown their ability to generate micro and nano structures of interest in several technological fields. Most of these techniques resort to deforming and stretching a liquid thread by applying forces of different nature (hydrodynamic, electrical, etc). Electrospray, employing electrical forces, is the most popular and powerful technique to produce particles in the nanometric range. A charged liquid jet issued from a Taylor cone may develop a special type of nonaxisymmetric instability which manifests itself as a series of fast and violent lashes of the charged jet. Recently, we have found that this instability is also present in electrosprays within a liquid bath which is essentially the same phenomenon as in air. However, within a liquid bath, the jet forms more easily and its oscillations are much slower. Taking advantage of this situation, we have used a high speed camera to experimentally characterize the whipping instability taking place inside liquid baths in terms of the governing parameters: flow rate and applied electric field.

  16. An experimental investigation of free and submerged miniature liquid jet array impingement heat transfer

    Microsoft Academic Search

    A. J. Robinson; E. Schnitzler

    2007-01-01

    Liquid water jet impingement cooling was investigated experimentally for both free-surface jet arrays and confined submerged jet arrays. The jet arrays consisted of straight holes of 1.0mm diameter arranged in rectangular arrays with spacings of 3, 5 and 7 jet diameters between adjacent jets. For the impingement surface area of 780mm2, these jet array configurations can be considered well populated,

  17. Modeling of Turbulence Effects on Liquid Jet Atomization and Breakup

    NASA Technical Reports Server (NTRS)

    Trinh, Huu; Chen, C. P.

    2004-01-01

    Recent experimental investigations and physical modeling studies have indicated that turbulence behaviors within a liquid jet have considerable effects on the atomization process. For certain flow regimes, it has been observed that the liquid jet surface is highly turbulent. This turbulence characteristic plays a key role on the breakup of the liquid jet near to the injector exit. Other experiments also showed that the breakup length of the liquid core is sharply shortened as the liquid jet is changed from the laminar to the turbulent flow conditions. In the numerical and physical modeling arena, most of commonly used atomization models do not include the turbulence effect. Limited attempts have been made in modeling the turbulence phenomena on the liquid jet disintegration. The subject correlation and models treat the turbulence either as an only source or a primary driver in the breakup process. This study aims to model the turbulence effect in the atomization process of a cylindrical liquid jet. In the course of this study, two widely used models, Reitz's primary atomization (blob) and Taylor-Analogy-Break (TAB) secondary droplet breakup by O Rourke et al. are examined. Additional terms are derived and implemented appropriately into these two models to account for the turbulence effect on the atomization process. Since this enhancement effort is based on a framework of the two existing atomization models, it is appropriate to denote the two present models as T-blob and T-TAB for the primary and secondary atomization predictions, respectively. In the primary breakup model, the level of the turbulence effect on the liquid breakup depends on the characteristic time scales and the initial flow conditions. This treatment offers a balance of contributions of individual physical phenomena on the liquid breakup process. For the secondary breakup, an addition turbulence force acted on parent drops is modeled and integrated into the TAB governing equation. The drop size formed from this breakup regime is estimated based on the energy balance before and after the breakup occurrence. The turbulence energy is also considered in this process.

  18. OSCILLATION D'UN JET LIQUIDE Par GUY LITTAYE.

    E-print Network

    Boyer, Edmond

    à l'extrémité d'un tube de verre court. Le liquide, l'eau en l'espèce, est amené au tube de verre par un tube de caoutchouc. Le tube de verre est fixé sur une lame d'acier qui effectue des observer exception- nellement un aspect semblable du jet alors que le tube de verre était soigneusement

  19. Fabrication of MEMS using liquid jet dispensing technique

    Microsoft Academic Search

    Sergey S. Sarkisov; Abdallah M. Darwish; Hossin A. Abdeldayem; Grigory Adamovsky; Mykola B. Kulishov; Curtis E. Banks; Jai C. Wang

    1999-01-01

    We describe a simple yet efficient technique of delineation of various polymer MEMS structures using computer driven liquid jet dispenser. A syringe-type dispenser with a replaceable needle is filled with a polymer solution and mounted on a vertical translation stage. The substrate is mounted on two-coordinate horizontal translation stage. Additional vertical translation arm is connected to the plunger of the

  20. Observations of breakup processes of liquid jets using real-time X-ray radiography

    NASA Technical Reports Server (NTRS)

    Char, J. M.; Kuo, K. K.; Hsieh, K. C.

    1988-01-01

    To unravel the liquid-jet breakup process in the nondilute region, a newly developed system of real-time X-ray radiography, an advanced digital image processor, and a high-speed video camera were used. Based upon recorded X-ray images, the inner structure of a liquid jet during breakup was observed. The jet divergence angle, jet breakup length, and fraction distributions along the axial and transverse directions of the liquid jets were determined in the near-injector region. Both wall- and free-jet tests were conducted to study the effect of wall friction on the jet breakup process.

  1. METHOD OF LIQUID-LIQUID EXTRACTION OF BLOOD SURROGATES FOR ASSESSING HUMAN EXPOSURE TO JET FUEL

    EPA Science Inventory

    A baseline method of liquid?liquid extraction for assessing human exposure to JP-8 jet fuel was established by extracting several representative compounds ranging from very volatile to semi-volatile organic compounds, including benzene, toluene, nonane, decane, undecane, tridec...

  2. Simulation of liquid-jet overflow in droplet deposition processes

    SciTech Connect

    Delplanque, J.P.; Rangel, R.H. [Univ. of California, Irvine, CA (United States)] [Univ. of California, Irvine, CA (United States)

    1999-05-28

    Porosity formation in spray deposition processes is investigated. The emphasis is on one possible mechanism of micro-pore formation during droplet spreading and solidification: liquid-jet overflow. To this end, the Navier-Stokes equations are solved numerically using finite differences and the free surface is tracked using the Volume of Fluid (VOF) method. A previously developed multi-directional solidification algorithm is adapted and implemented in the Navier-Stokes solver to perform numerical simulations of liquid-metal droplet impact, spreading, and solidification. The results obtained allow a detailed description of the liquid-jet overflow mechanism and of the resulting solidified disk morphology. The influence of the Weber and Reynolds numbers, the solidification constant, and the contact angle are investigated.

  3. Modeling of turbulence effect on liquid jet atomization

    NASA Astrophysics Data System (ADS)

    Trinh, Huu Phuoc

    Recent experimental investigations and physical modeling studies have indicated that turbulence behaviors within a liquid jet have considerable effects on the atomization process. Such turbulent flow phenomena are encountered in most practical applications of common liquid spray devices. Most existing atomization models do not account for the turbulence effects. Only limited attempts have been made to model the subject effects on the liquid jet disintegration; however, they treat the turbulence either as an only source or a primary driver in the breakup process. This doctoral research aims to model the effects of turbulence, occurring inside a cylindrical liquid jet, to its atomization process. The modeling effort enhances the predictions of the liquid jet breakup in more physically realistic operating conditions. In the course of this study, the two widely used atomization models, the Kelvin-Helmholtz (KH) instability of Reitz and the Taylor-Analogy-Breakup (TAB) of O'Rourke et al., portraying the primary liquid jet disintegration and the secondary droplet breakup respectively, are examined. Additional terms are formulated and implemented appropriately into these two models to account for the turbulence effect on the atomization process. In the primary breakup model, the turbulence inside the liquid jet is characterized by the turbulence scales and the initial turbulence quantities when incorporating into the Reitz model. Meanwhile, an additional turbulence effect acting on the parent drops is modeled and integrated into the TAB governing equation for the secondary breakup regime. The proposed extension of atomization models is assessed with a computer code written for simple flow situations. The results for the flow conditions examined in this study indicate that the turbulence terms are significant in comparison with other terms in the models. In the primary breakup regime, the turbulent liquid jet tends to break up into large drops while its intact core is slightly shorter than the ones without the turbulence. In contrast, the secondary droplet breakup with the inside liquid turbulence consideration produces smaller drops as compared to the case without the turbulence. Overall, the results are consistent with experimental observations from other researchers. Finally, the present models are also programmed into an existing computational fluid dynamic (CFD) code, and simulations for several experimental flow conditions are performed. The computational results suggest that the existing KH and TAB models tend to under-predict the product drop size and the spray angle. On the other hand, the proposed models provide the predictions, which agree reasonably well with available measured data. In summary, this research effort contributes to the improvement of the prediction in the liquid jet atomization processes. The additional terms, representing the turbulence effects on the jet breakup, can be incorporated easily into the two well-known atomization models. Suggested numerical schemes for solving the proposed models also are presented in this study. Therefore, the proposed enhancements can be implemented conveniently into existing CFD codes.

  4. Multiple Pulses from Plasma Jets onto Liquid Covered Tissue

    NASA Astrophysics Data System (ADS)

    Norberg, Seth; Tian, Wei; Johnsen, Eric; Kushner, Mark J.

    2014-10-01

    Atmospheric pressure plasma jets are being studied in the treatment of biological surfaces that are often covered by a thin layer of liquid. The plume of the plasma jet contains neutral radicals and charged species that solvate into the liquid and eventually form terminal species that reach the tissue below. The contribution of neutral and charged species to reactivity in the liquid is sensitive to whether the active plasma plume touches the liquid. In this paper, we discuss results from modeling the production of the aqueous species formed from the interaction of the plume of plasma jets over multiple pulses with the water layer, and the fluences of the species to the underlying tissue. The model used in this study, nonPDPSIM, solves transport equations for charged and neutral species and electron energy, Poisson's equation for the electric potential, and Navier-Stokes equations for the neutral gas flow. Radiation transport includes photoionization of O2 and H2O in the gas and liquid phases and photodissocation of H2Oaq in the liquid. Multiple pulses when the plasma plume touches and does not touch the liquid will be examined. Two regimes of hydrodynamics will be discussed - low repetition rates where the neutral radicals are blown away before the next discharge pulse, and high repetition rate when the plasma plume interacts with neutral radicals from previous pulses. The density of aqueous ions produced in the liquid layer is strongly dependent on whether the plasma effluent touches or does not touch the water surface. Work supported by DOE Office of Fusion Energy Science and NSF.

  5. Droplet formation for liquid monopropellant jets

    Microsoft Academic Search

    Nelson A. Macken

    1987-01-01

    The hydrodynamic development of droplets for conditions approximating those in the combustion chamber of regenerative liquid propellant guns has been investigated. The report contains a literature survey and discussion of various breakup mechanisms. Aerodynamic interaction is analyzed using classical stability theory and a formulation applied to anticipated working conditions. The model predicts mass removed and droplet size as a function

  6. The Plunge Phase of Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Nunes, Arthur; McClure, John; Avila, Ricardo

    2005-01-01

    Torque and plunge force during the initial plunge phase in Friction Stir Welding were measured for a 0.5 inch diameter pin entering a 2219 aluminum alloy plate. Weld structures were preserved for metallographic observation by making emergency stops at various plunge depths. The plunging pin tool is seen to be surrounded by a very fine grained layer of recrystallized metal extending substantially below the bottom of the pin, implying a shear interface in the metal below and not at the tool-metal interface. Torque and plunge force during the initial plunge phase in Friction Stir Welding are calculated from a straight forward model based on a concept to plastic flow in the vicinity of the plunging tool compatible with structural observations. The concept: a disk of weld metal seized to and rotating with the bottom of the pin is squeezed out laterally by the plunge force and extruded upwards in a hollow cylinder around the tool. As the shear surface separating rotating disk from stationary weld metal engulfs fresh metal, the fresh metal is subjected to severe shear deformation, which results in its recrystallization. Encouraging agreement between computations and measured torque and plunge force is obtained.

  7. Breakup of Laminar Jet into Drops in Immiscible Liquid-Liquid Systems with Mass Transfer

    Microsoft Academic Search

    S. Homma; G. Tryggvason; J. Koga; S. Matsumoto

    1998-01-01

    The breakup of an axisymmetric jet into drops in immiscible liquid-liquid systems with mass transfer is investigated numerically. It is assumed that the solute concentration only affects the interfacial tension, so that the density and the viscosity of both phases are not influenced by the mass transfer. The axisymmetric Navier-Stokes equations, with a convection\\/diffusion equation for a single solute are

  8. Effect of gas mass flux on cryogenic liquid jet breakup

    NASA Technical Reports Server (NTRS)

    Ingebo, R. D.

    1992-01-01

    A scattered-light scanning instrument developed at NASA Lewis Research Center was used to measure the characteristic drop size of clouds of liquid nitrogen droplets. The instrument was calibrated with suspensions of monosized polystyrene spheres. In this investigation of the mechanism of liquid nitrogen jet disintegration in a high-velocity gas flow, the Sauter mean diameter, D32, was found to vary inversely with the nitrogen gas mass flux raised to the power 1.33. Values of D32 varied from 5 to 25 microns and the mass flux exponent of 1.33 agrees well with theory for liquid jet breakup in high-velocity gas flows. The loss of very small droplets due to the high vaporization rate of liquid nitrogen was avoided by sampling the spray very close to the atomizer, i.e., 1.3 cm downstream of the nozzle orifice. The presence of high velocity and thermal gradients in the gas phase also made sampling of the particles difficult. As a result, it was necessary to correct the measurements for background noise produced by both highly turbulent gas flows and thermally induced density gradients in the gas phase.

  9. OK432 Sclerotherapy of Plunging Ranula in 21 Patients: It Can Be a Substitute for Surgery

    Microsoft Academic Search

    M. H. Rho; D. W. Kim; J. S. Kwon; S. W. Lee; Y. S. Sung; Y. K. Song; M. G. Kim; S. G. Kim

    BACKGROUND AND PURPOSE: Although first-choice therapy for the ranula is surgery, this choice presents technical difficulties and frequent recurrences because of insufficient surgery. We evaluated the efficacy of OK-432 sclerosis of the plunging ranula as a substitute for surgery. METHODS: Twenty-one patients with plunging ranula were treated with intralesional injection of OK-432. The liquid content of the ranula was aspirated

  10. Spray measurements of aerothermodynamic effect on disintegrating liquid jets

    NASA Technical Reports Server (NTRS)

    Ingebo, Robert D.

    1991-01-01

    An experimental investigation was made to determine the effect of atomizing gas mass flux and temperature on liquid jet breakup in sonic velocity gas flow. Characteristic drop size data were obtained by using the following atomizing gases: nitrogen, argon, and helium to breakup water jets in high velocity gas flow. A scattered light scanning instrument developed at Lewis Research Center was used to measure Sauter mean diameter (SMD). The three gases gave a molecular weight range of 4 to 40 and atomizing gas mass flux and temperature were varied from 6 to 50 g/sq cm and 275-400 K, respectively. The ratio of liquid jet diameter to SMD, D(sub 0)/D(sub 32), was correlated with aerodynamic and liquid-surface force ratios, i.e., the product of the Weber and Reynolds number, We Re, the gas to liquid density ratio, rho(sub g)/rho(sub 1) g and also the molecular scale dimensionless group, rho(sub 1)(Vm exp 3)/ mu(sub 1) g, to give the following expression: D(sub 0)/D(sub 32) = 0.90 x 10(exp -8) x (We Re rho sub g/rho sub 1)exp 0.44 x (rho sub 1 Vm exp 3/mu sub 1 g)exp 0.67 where We Re = ((rho sub g)exp 2(D sub 0)exp 2(V sub C)exp3))/ mu sub 1 sigma, mu sub 1 is liquid viscosity, sigma is surface tension, V sub C is the acoustic gas velocity, V sub m is the RMS velocity of gas molecules, and g is the acceleration of gas molecules due to gravity. Good agreement was obtained with atomization theory for liquid-jet breakup in the regime of aerodynamic stripping. Also, due to its low molecular weight and high acoustic velocity, helium was considerably more effective than nitrogen or argon in producing small-droplet sprays with values of D(sub 32) on the order of 5 microns.

  11. To be, or not to be... -instabilities on a liquid jet penetrated into a flowing bath-

    E-print Network

    Hattori, Kaoru

    2010-01-01

    We conduct a series of experiments with a special interest on a penetration process and instabilities arisen on a liquid jet impinged to a liquid of the same kind flowing in a channel. The impinged jet penetrates into the flowing bath accompanying with entrainment of the ambient immiscible gas, which results in the impinged jet wrapped by the entrained gas as a 'sheath.' This sheath formation enables the impinged jet to survive in the fluid in the channel without coalescing until the entrained-air sheath breaks down. Occasionally a 'cap' of the entrained air is formed at the tip of the penetrated jet, and the jet elongates like a long balloon.

  12. Production of jet fuel from coal-derived liquids

    SciTech Connect

    Furlong, M.W.; Fox, J.D.; Masin, J.G.; Soderberg, D.J.

    1987-01-01

    Amoco and Lummus Crest are evaluating the process options and economics for upgrading the naphtha, crude phenols, and tar oil by-products from the Great Plains Coal Gasification Plant to jet fuels and other salable products. Analytical characterizations of these three by-products indicate the range of products that can be manufactured from each, and potential problems which could be encountered during refining. These characterizations, along with limited experimental data and Amoco's proprietary process models, were used to design conceptual processing schemes for maximizing the production of Grades JP-4, JP-8, and high density (JP-8X) jet fuels from the by-product liquids. In addition to the maximum jet fuel schemes, conceptual designs have also been formulated for maximizing profits from refining of the Great Plains by-products. Conceptual processing schemes for profitable production of JP-4, JP-8, and JP-8X have been developed, as has a maximum profit'' case. All four of these additional cases have now been transferred to Lummus for design and integration studies. Development of these schemes required the use of linear programming technology. This technology includes not only conventional refining processes which have been adapted for use with coal-derived liquids (e.g. hydrotreating, hydrocracking), but also processes which may be uniquely suited to the Great Plains by-products such as cresylic acid extraction, hydordealkylation, and needle coking. 6 figs., 3 tabs.

  13. Disintegration of a Round Liquid Jet due to Impact on a Superhydrophobic Surface

    NASA Astrophysics Data System (ADS)

    Jalaal, Maziyar; Stoeber, Boris

    2013-11-01

    Liquid jet breakup has several applications such as Inkjet printers, diesel fuel injectors, and paint sprays. Very recently liquid jets have been shown to be useful for small volume transportation (Clestini et al. Soft Matter, 2010), where a micro-scale liquid jet on superhydrophobic surface was investigated. Although the instability of the liquid jet for some circumstances was shown, the disintegration of the liquid jet was not discussed. In the present study, we aim to analyze the breakup of a micro liquid jet due to inclined impact to a superhydrophobic surface. A range of Weber and Reynolds numbers have been explored experimentally. Water-glycerin solution as the working fluid. Generally, it is shown that the liquid jet forms a disc-like film over the surface and further rebounds (``bouncing jet''). A simple energy balance method is provided to estimate the diameter of the disc-like film. It is shown, for the case of low viscosity (large Re), this parameter is logarithmically proportional to the normal Weber number. Additionally, linear stability analysis for viscous jets provides a good estimate of droplet size. From an application point of view, using superhydrophobic surfaces 1) enables rebound of the liquid jet 2) advances the breakup point (shorten the breakup length).

  14. Korteweg-de Vries solitons on electrified liquid jets

    NASA Astrophysics Data System (ADS)

    Wang, Qiming; Papageorgiou, Demetrios T.; Vanden-Broeck, Jean-Marc

    2015-06-01

    The propagation of axisymmetric waves on the surface of a liquid jet under the action of a radial electric field is considered. The jet is assumed to be inviscid and perfectly conducting, and a field is set up by placing the jet concentrically inside a perfectly cylindrical tube whose wall is maintained at a constant potential. A nontrivial interaction arises between the hydrodynamics and the electric field in the annulus, resulting in the formation of electrocapillary waves. The main objective of the present study is to describe nonlinear aspects of such axisymmetric waves in the weakly nonlinear regime, which is valid for long waves relative to the undisturbed jet radius. This is found to be possible if two conditions hold: the outer electrode radius is not too small, and the applied electric field is sufficiently strong. Under these conditions long waves are shown to be dispersive and a weakly nonlinear theory can be developed to describe the evolution of the disturbances. The canonical system that arises is the Kortweg-de Vries equation with coefficients that vary as the electric field and the electrode radius are varied. Interestingly, the coefficient of the highest-order third derivative term does not change sign and remains strictly positive, whereas the coefficient ? of the nonlinear term can change sign for certain values of the parameters. This finding implies that solitary electrocapillary waves are possible; there are waves of elevation for ? >0 and of depression for ? <0 . Regions in parameter space are identified where such waves are found.

  15. Modeling of Turbulence Effects on Liquid Jet Atomization and Breakup

    NASA Technical Reports Server (NTRS)

    Trinh, Huu P.; Chen, C. P.

    2005-01-01

    Recent experimental investigations and physical modeling studies have indicated that turbulence behaviors within a liquid jet have considerable effects on the atomization process. This study aims to model the turbulence effect in the atomization process of a cylindrical liquid jet. Two widely used models, the Kelvin-Helmholtz (KH) instability of Reitz (blob model) and the Taylor-Analogy-Breakup (TAB) secondary droplet breakup by O Rourke et al, are further extended to include turbulence effects. In the primary breakup model, the level of the turbulence effect on the liquid breakup depends on the characteristic scales and the initial flow conditions. For the secondary breakup, an additional turbulence force acted on parent drops is modeled and integrated into the TAB governing equation. The drop size formed from this breakup regime is estimated based on the energy balance before and after the breakup occurrence. This paper describes theoretical development of the current models, called "T-blob" and "T-TAB", for primary and secondary breakup respectivety. Several assessment studies are also presented in this paper.

  16. Fabrication of MEMS using liquid jet dispensing technique

    NASA Astrophysics Data System (ADS)

    Sarkisov, Sergey S.; Darwish, Abdalla M.; Abdeldayem, Hossin A.; Adamovsky, Grigory; Kulishov, Mykola B.; Banks, Curtis E.; Wang, JaChing

    1999-03-01

    We describe a simple yet efficient technique of delineation of various polymer MEMS structures using computer driven liquid jet dispenser. A syringe-type dispenser with a replaceable needle is filled with a polymer solution and mounted on a vertical translation stage. The substrate is mounted on two-coordinate horizontal translation stage. Additional vertical translation arm is connected to the plunger of the syringe. Vertical translation provides positioning of the needle at a certain height over the substrate. Delineation is accomplished when the syringe plunger, being pushed down by the vertical translation arm, dispenses the liquid on the substrate at a programmable flow rate simultaneously with horizontal motion of the substrate with respect to the needle. Horizontal motion is done along a programmable trajectory at a programmable sped. Comparing to conventional methods, the proposed device consumes three order of magnitude less amount of material for the fabrication of similar MEMS structures. In addition, we describe a supplement to the liquid delineation system in the form of a microscope objective head connected to a noncoherent UV source with a multimode optical fiber. The head can serve as a tool for UV curing of the polymer material deposited with the jet dispenser as well as a separate UV writing tool. In conclusion, we describe the calculation technique for the distribution of the electric field in electrically or optically controlled ferroelectric polymer MEMS fabricated by the proposed technique.

  17. Impinging jet spray formation using non-Newtonian liquids

    NASA Astrophysics Data System (ADS)

    Rodrigues, Neil S.

    Over the past two decades there has been a heightened interest in implementing gelled propellants for rocket propulsion, especially for hypergolic bi-propellants such as monomethylhydrazine (MMH) and nitrogen tetroxide oxidizer (NTO). Due to the very high level of toxicity of hypergolic liquid rocket propellants, increasing safety is an important area of need for continued space exploration and defense operations. Gelled propellants provide an attractive solution to meeting the requirements for safety, while also potentially improving performance. A gelling agent can be added to liquid propellants exhibiting Newtonian behavior to transform the liquid into a non-Newtonian fluid with some solid-like behavior, i.e. a gel. Non-Newtonian jet impingement is very different from its Newtonian counterpart in terms of fluid flow, atomization, and combustion. This is due to the added agents changing physical properties such as the bulk rheology (viscosity) and interfacial rheology (surface tension). Spray characterization of jet impingement with Newtonian liquids has been studied extensively in existing literature. However, there is a scarcity in literature of studies that consider the spray characterization of jet impingement with gelled propellants. This is a rather critical void since a major tradeoff of utilizing gelled propellants is the difficulty with atomization due to the increased effective viscosity. However, this difficulty can be overcome by using gels that exhibit shear-thinning behavior---viscosity decreases with increasing strain rate. Shear-thinning fluids are ideal because they have the distinct advantage of only flowing easily upon pressure. Thereby, greatly reducing the amount of propellant that could be accidentally leaked during both critical functions such as liftoff or engagement in the battlefield and regular tasks like refilling propellant tanks. This experimental work seeks to help resolve the scarcity in existing literature by providing drop size and drop velocity mean values and distribution of several non-Newtonian liquids using a like-on-like impinging jet doublet. The drop size and drop velocity are important areas of study because of the effect on mass transfer and mass dispersal. Phase Doppler Anemometry (PDA) is used to measure the drop diameter and drop velocity. The drop diameter is measured by finding a phase difference between two signals. The drop velocity is measured using Laser Doppler Anemometry (LDA), which is based on the Doppler shift. Parametric studies are conducted based on dimensionless groups, impinging jet geometry, and spatial position. The investigated non-Newtonian liquids collapse onto a single mean diameter versus Reynolds number curve. However, this behavior is not observed for the gels due to differences in surface tension and molecular structure. In general, increasing the inertial force results in smaller drops and greater drop velocities. The different geometric parameters are observed to have varying degrees of influence, based on the propellant simulant considered. Larger drops with lower axial velocities are generally observed with increasing transverse distances from the centerline of the impinging jet spray.

  18. Atmospheric pressure plasma jets interacting with liquid covered tissue: touching and not-touching the liquid

    NASA Astrophysics Data System (ADS)

    Norberg, Seth A.; Tian, Wei; Johnsen, Eric; Kushner, Mark J.

    2014-11-01

    In the use of atmospheric pressure plasma jets in biological applications, the plasma-produced charged and neutral species in the plume of the jet often interact with a thin layer of liquid covering the tissue being treated. The plasma-produced reactivity must then penetrate through the liquid layer to reach the tissue. In this computational investigation, a plasma jet created by a single discharge pulse at three different voltages was directed onto a 200?µm water layer covering tissue followed by a 10?s afterglow. The magnitude of the voltage and its pulse length determined if the ionization wave producing the plasma plume reached the surface of the liquid. When the ionization wave touches the surface, significantly more charged species were created in the water layer with H3O+aq, O3?aq, and O2?aq being the dominant terminal species. More aqueous OHaq, H2O2aq, and O3aq were also formed when the plasma plume touches the surface. The single pulse examined here corresponds to a low repetition rate plasma jet where reactive species would be blown out of the volume between pulses and there is not recirculation of flow or turbulence. For these conditions, NxOy species do not accumulate in the volume. As a result, aqueous nitrites, nitrates, and peroxynitrite, and the HNO3aq and HOONOaq, which trace their origin to solvated NxOy, have low densities.

  19. Surfactant adsorption and Marangoni flow in liquid jets. I. Experiments.

    PubMed

    Battal, Turgut; Bain, Colin D; Weiss, Michael; Darton, Richard C

    2003-07-01

    The adsorption of surfactants at an expanding liquid surface has been studied in a gravity-driven laminar water jet with Reynolds numbers in the range from 1000 to 2000. Surface concentrations of hexadecyltrimethylammonium bromide (C(16)TAB) were deduced from ellipsometric measurements, using a calibration made previously with neutron reflection. Simultaneous measurements of the velocity profile within the jet were made with laser Doppler velocimetry. These two noninvasive techniques were able to measure conditions to within 1 mm of the nozzle, where rates of surface expansion were as high as 300 s(-1). For the laminar jet without surfactant, the measurements are in excellent agreement with CFD calculations and with the theoretical result that the surface velocity varies as z(1/3), where z is the distance from the nozzle. Close to the nozzle the high rate of surface expansion drives both rapid diffusional transport to the surface, and rapid convection on the surface, resulting in a low concentration of surfactant. Higher concentrations of surfactant downstream cause a Marangoni stress which decelerates the surface-an effect clearly shown by the velocity data. In the presence of 0.2 M salt, which significantly depresses the cmc, the adsorption of C(16)TAB is greatly reduced, probably because it forms cylindrical micelles, which diffuse much more slowly than free monomers. The apparatus is shown to be a very suitable platform for investigating surfactant adsorption and Marangoni flows under carefully controlled hydrodynamic conditions. PMID:12804910

  20. Experimental Study and Numerical Simulation on Interaction of Plasma Jet and Liquid media

    Microsoft Academic Search

    Yonggang Yu; Shanheng Yan; Na Zhao; Xin Lu; Yanhuang Zhou

    2009-01-01

    The interaction mechanism of plasma jet with liquid media is one of the most important problems in the study of interior ballistic of electrothermal chemical propulsion. The propagation form and the interaction mechanism of plasma jet in water are studied experimentally in this paper. The plasma jet is generated by the discharging of pulse power in a polyethylene capillary. The

  1. Bouncing jet: A Newtonian liquid rebounding off a free surface Matthew Thrasher,* Sunghwan Jung,

    E-print Network

    Weeks, Eric R.

    Bouncing jet: A Newtonian liquid rebounding off a free surface Matthew Thrasher,* Sunghwan Jung horizontally with respect to the jet. Previous observations of jets rebounding off a bath e.g., the Kaye effect's surface, is bent upward, and under- goes a short flight. After rebounding once more off the sur- face

  2. Effect of nozzle length-to-diameter ratio on atomization of turbulent liquid jets

    NASA Astrophysics Data System (ADS)

    Osta, Anu Ranjan

    Breakup of liquid jets is of considerable interest motivated by its applicability in combustion and propulsion systems (CI and SI engines), and agricultural fertilizer/pesticide sprays, among others. Almost all of the practical liquid injectors introduce some degree of turbulence in the liquid jet leaving the injector passage and an intriguing question is the relative importance of the liquid turbulence, cavitation, and the aerodynamic forces in the breakup processes of fuel injectors. A better design of liquid fuel injector would reduce pollutants and increase the efficiency of liquid fuel combustion processes. An experimental study to investigate the effect of nozzle length to diameter ratio on the surface properties of turbulent liquid jets in gaseous crossflow and still air was carried out. Straight cavitation-free nozzles with length/diameter ratios of 10, 20 and 40 were used to generate turbulent liquid jets in gaseous crossflow. The present study was limited to small Ohnesorge number liquid jets (Oh < 0.01) injected in crossflow within the shear breakup regime (WeG > 110). The diagnostics consisted of pulsed shadowgraphy, pulsed digital holographic microscopy and x-ray diagnostics. The x-ray tests were conducted at the Advanced Photon Source (APS) facility of Argonne National Laboratory. The test matrix was designed to maintain the same aerodynamic forces in order to isolate the effects of jet turbulence on the breakup process. The measurements included liquid jet surface properties, breakup location of the liquid column as a whole, the breakup regime transitions, bubble size inside the jet and seeding particle displacement inside the jet structures. The results include the jet surface characteristics, the liquid column breakup lengths, bubble growth, and phenomenological analysis to explain the observed results. It is observed that for a jet breakup in crossflow the injector passage length does play a role in determining the breakup length as well as influence the characteristics of the jet upwind surface. The present results for jet breakup in still air also show that the ligament distribution follows an arrangement along the jet surface and bubble formation associated with the jet breakup as well. The x-ray diagnostic allowed the surface and internal topography of fuel jets to be visualized and the breakup mechanism in the dense-spray near-injector region to be revealed.

  3. Ultrafast X-ray study of dense-liquid-jet flow dynamics using structure-tracking

    E-print Network

    Loss, Daniel

    LETTERS Ultrafast X-ray study of dense-liquid-jet flow dynamics using structure. The wide scientific and industrial interest in the study of multiphase flow ranges from blood flow High-speed liquid jets and sprays are complex multiphase flow phenomena with many important industrial

  4. Photoionization of Sodium Salt Solutions in a Liquid Jet

    SciTech Connect

    Grieves, G. A.; Petrik, Nikolay G.; Herring-Captain, J.; Olanrewaju, B.; Aleksandrov, A.; Tonkyn, Russell G.; Barlow, Stephan E.; Kimmel, Gregory A.; Orlando, Thomas M.

    2008-06-05

    A liquid microjet was employed to examine the gas/liquid interface of aqueous sodium halide (Na+X-, X=Cl, Br, I) salt solutions. Laser excitation at 193 nm produced and removed cations of the form H+(H2O)n and Na+(H2O)m from liquid jet surfaces containing either NaCl, NaBr or NaI. The protonated water cluster yield varied inversely with increasing salt concentration, while the solvated sodium ion cluster yield varied by anion type. The distribution of H+(H2O)n at low salt concentration is identical to that observed from low-energy electron irradiated amorphous ice and the production of these clusters can be accounted for using a localized ionization/Coulomb expulsion model. Production of Na+(H2O)m is not accounted for by this model but requires ionization of solvation shell waters and a contact ion/Coulomb expulsion mechanism. The reduced yields of Na+(H2O)m from high concentration (10-2 and 10-1 M) NaBr and NaI solutions indicate a propensity for Br- and I- at the solution surfaces and interfaces. This is supported by the observation of multiphoton induced production and desorption of Br+ and I+ from the 10-2 and 10-1 M solution surfaces.

  5. Measurement of intact-core length of atomizing liquid jets by image deconvolution

    NASA Astrophysics Data System (ADS)

    Woodward, Roger; Burch, Robert; Kuo, Kenneth; Cheung, Fan-Bill

    1993-11-01

    The investigation of liquid jet breakup and spray development is critical to the understanding of combustion phenomena in liquid propellant rocket engines. Much work has been done to characterize low-speed liquid jet breakup and dilute sprays, but atomizing jets and dense sprays have yielded few quantitative measurements due to their high liquid load fractions and hence their optical opacity. Focus was on a characteristic of the primary breakup process of round liquid jets, namely the length of the intact-liquid core. The specific application considered is that of shear-coaxial-type rocket engine injectors in which liquid oxygen is injected through the center post while high velocity gaseous hydrogen is injected through a concentric annulus, providing a shear force to the liquid jet surface. Real-time x ray radiography, capable of imaging through the dense two-phase region surrounding the liquid core, is used to make the measurements. The intact-liquid-core length data were obtained and interpreted using two conceptually different methods to illustrate the effects of chamber pressure, gas-to-liquid momentum ratio, and cavitation.

  6. The Bouncing Jet: A Newtonian Liquid Rebounding off a Free Surface

    E-print Network

    Thrasher, Matthew; Pang, Yee Kwong; Chuu, Chih-Piao; Swinney, Harry L

    2007-01-01

    We find that a liquid jet can bounce off a bath of the same liquid if the bath is moving horizontally with respect to the jet. Previous observations of jets rebounding off a bath (e.g. Kaye effect) have been reported only for non-Newtonian fluids, while we observe bouncing jets in a variety of Newtonian fluids, including mineral oil poured by hand. A thin layer of air separates the bouncing jet from the bath, and the relative motion replenishes the film of air. Jets with one or two bounces are stable for a range of viscosity, jet flow rate and velocity, and bath velocity. The bouncing phenomenon exhibits hysteresis and multiple steady states.

  7. Experimental and theoretical studies of vertical annular liquid jets

    Microsoft Academic Search

    J. I. Ramos

    1990-01-01

    Theoretical studies are described of vertical annular jets, the conditions are determined under which vertical jets form an enclosed volume which can be used as a chemical reactor, the influence is assessed of the nozzle gap width, nozzle geometry, pressure difference across the annular jet, and Froude, Weber and Reynolds numbers on the annular jet's covergence length, and the mass

  8. Thinning and rupture of liquid films by moving slot jets.

    PubMed

    Berendsen, Christian W J; Zeegers, Jos C H; Darhuber, Anton A

    2013-12-23

    We present systematic experiments of the rupture and dewetting of thin films of a nonvolatile polar liquid on partially wetting substrates due to a moving slot jet, which impinges at normal incidence. The relative motion was provided by a custom-built spin coater with a bidirectionally accessible axis of rotation that enabled us to measure film thickness profiles in situ as a function of substrate velocity using dual-wavelength interference microscopy. On partially wetting polymeric substrates, dry spots form in liquid films with a residual thickness well below 1 ?m. We measured the density of dry spots as well as the density and size distribution of the residual droplets as a function of film thickness. In a certain parameter range, the droplet distributions exhibit pronounced anisotropy due to the effect of long-range shear stresses on the dewetting rim instability. We find robust power-law scaling relations over a large range of film thicknesses and a striking similarity to literature data obtained with ultrathin polymer melt layers on silicon substrates. PMID:24299431

  9. Microfluidic liquid jet system with compatibility for atmospheric and high-vacuum conditions.

    PubMed

    Trebbin, Martin; Krüger, Kilian; DePonte, Daniel; Roth, Stephan V; Chapman, Henry N; Förster, Stephan

    2014-05-21

    We present microfluidic chip based devices that produce liquid jets with micrometer diameters while operating at very low flow rates. The chip production is based on established soft-lithographical techniques employing a three-layer design protocol. This allows the exact, controlled and reproducible design of critical parts such as nozzles and the production of nozzle arrays. The microfluidic chips reproducibly generate liquid jets exiting at perfect right angles with diameters between 20 ?m and 2 ?m, and under special circumstances, even down to 0.9 ?m. Jet diameter, jet length, and the domain of the jetting/dripping instability can be predicted and controlled based on the theory for liquid jets in the plate-orifice configuration described by Gañán-Calvo et al. Additionally, conditions under which the device produces highly reproducible monodisperse droplets at exact and predictable rates can be achieved. The devices operate under atmospheric and under vacuum conditions making them highly relevant for a wide range of applications, for example, for free-electron lasers. Further, the straightforward integration of additional features such as a jet-in-jet is demonstrated. This device design has the potential to integrate more features based on established microfluidic components and may become a standard device for small liquid jet production. PMID:24671443

  10. Quantitative determination of wear metals in engine oils using laser-induced breakdown spectroscopy: A comparison between liquid jets and static liquids

    Microsoft Academic Search

    Pavel Yaroshchyk; Richard J. S. Morrison; Doug Body; Bruce L. Chadwick

    2005-01-01

    A comparison of laser-induced breakdown spectroscopy (LIBS) sensitivity in laminar liquid jets and at the surface of a static liquid has been performed. Limits of detection (LODs) have been estimated for Na, Mg, Al, Ca, Ti, V, Cr, Mn, Ni, Fe, Cu, Zn, Mo, Ag, Cd, and Ba under similar conditions using both experimental arrangements. LODs in liquid jets are

  11. On the spatial stability of a liquid jet in the presence of vapor cavities

    NASA Astrophysics Data System (ADS)

    Lü, Ming; Ning, Zhi; Lu, Mei; Yan, Kai; Fu, Juan; Sun, Chunhua

    2013-11-01

    A dispersion equation describing the effect of temperature differences on the stability of three-dimensional cylindrical liquid jets in the presence of vapor cavities is presented by the use of linear stability analysis. The mathematical model and its solving method are verified by comparing them with the data in the literature, and then the effect of temperature differences between jet and surrounding gas on the spatial stability of liquid jet is investigated. Some conclusions can be drawn from the results of this investigation: (1) the temperature difference destabilizes the liquid jet when the jet liquid is cooler than the surrounding gas, (2) the smallest atomized droplet without taking into account the effect of temperature differences is significantly larger than that when the effect of temperature differences is taken into account, (3) the effect of temperature differences on the stability of liquid jet has little relationship with azimuthal wave modes, (4) cavitation destabilizes the liquid jet when the value of the bubble volume fraction is not greater than 0.1 (0 ? ? ? 0.1), and the temperature difference can weaken this effect of cavitation on the stability of liquid jet, and (5) cavitation is responsible for generating smaller droplets, the effect of cavitation on the critical wave number with and without taking into account the effect of temperature differences is quite different, and temperature difference is likely to fully restrain the effect of cavitation on the critical wave number; however, cavitation is again responsible for generating smaller droplets despite the effect of temperature differences when the bubble volume fraction ? = 0.1. These findings may explain some observations of practical atomizer performance.

  12. Collective behavior in a granular jet: emergence of a liquid with zero surface tension.

    PubMed

    Cheng, Xiang; Varas, German; Citron, Daniel; Jaeger, Heinrich M; Nagel, Sidney R

    2007-11-01

    We perform the analog to "water bell" experiments with granular jets. Rebounding from cylindrical targets, wide granular jets produce sheets or cones with shapes that mimic a zero-surface-tension liquid. The jets' particulate nature appears when the number of particles in the cross section is decreased: the emerging structures broaden, gradually disintegrating into diffuse sprays. The experiment has a counterpart in the behavior of quark-gluon plasmas generated by colliding heavy ions. There, a high collision density gives rise to collective behavior also described as a liquid. PMID:17995441

  13. Plunge location of sediment driven hyperpycnal river discharges considering bottom friction, lateral entrainment, and particle settling

    NASA Astrophysics Data System (ADS)

    Strom, K. B.; Bhattacharya, J.

    2012-12-01

    River discharges with very high sediment loads have the potential to develop into plunging hyperpycnal flows that transition from a river jet to a turbidity current at some location basinward of the river mouth due to the density difference between the turbid river and the receiving water body. However, even if the bulk density of the turbid river is greater than that of the receiving lake or ocean, some distance is needed for the forward inertia of the river to dissipate so that the downward gravitational pull can cause the system to collapse into a subaqueous turbidity current. This collapsing at the plunge point has been found to occur when the densimetric Froude number decreases to a value between 0.3 < Frd < 0.7 (Fang and Stefan 2000, Parker and Toniolo 2007, Dai and Garcia 2010, Lamb et al. 2010). In 2D channel flow analysis at the plunge point, this has led to the concept of a two-fold criterion for plunging. The first is simply for the need of high enough suspended sediment concentration to overcome the density difference between the river fluid and the fluid of the receiving water. The second is the need for sufficiently deep water to reduce the densimetric Froude below the critical value for plunging, which leads to dependence of plunging on the receiving water basin topography (Lamb et al. 2010). In this analysis, we expand on past work by solving a system of ODE river jet equations to account for bottom friction, lateral entrainment of ambient fluid, and particle settling between the river mouth and the plunge location. Typical entrainment and bottom friction coefficients are used and the model is tested against the laboratory density current data of Fang and Stefan (1991). A suite of conditions is solved with variable river discharge velocity, aspect ratio, suspended sediment concentration, and particle size; a range of salinity values and bottom slopes are used for the receiving water body. The plunge location is then expressed as a function of the boundary conditions at the river mouth and those of the receiving water. The relationships can be used for modern systems, but can also help to put reasonable bounds on paleo-hydraulic setting. References Dai, A. & Garcia, M. H. (2010). Energy Dissipative Plunging Flows. Journal of Hydraulic Engineering, 136(8), 519-523. Fang, X. & Stefan, H. G. (1991). Integral Jet Model for Flow from an Open Channel into a Shallow Lake or Reservoir. St. Anthony Falls Hydraulic Laboratory. Fang, X. & Stefan, H. G. (2000). Dependence of dilution of a plunging discharge over a sloping bottom on inflow conditions and bottom friction. Journal of Hydraulic Research, 38(1), 15-25. Lamb, M. P., McElroy, B., Kopriva, B., Shaw, J., & Mohrig, D. (2010). Linking river-flood dynamics to hyperpycnal-plume deposits: Experiments, theory, and geological implications. Geological Society of America Bulletin, 122(9/10), 1389-1400. Parker, G. & Toniolo, H. (2007). Note on the Analysis of Plunging of Density Flows. Journal of Hydraulic Engineering, 133(6), 690-694.

  14. Experimental study of a liquid jet flowing into another immiscible liquid ``a local analysis of the interface''

    NASA Astrophysics Data System (ADS)

    Tadrist, L.; Alaoui, E. K. O.; Occelli, R.; Pantaloni, J.

    1991-12-01

    This paper describes an experimental study of a liquid jet leaving a cylindrical nozzle under gravity. A special optical system was used to study the spatial and temporal interface variations between two liquids. A photoelectric cell was used to measure the light intensity and to obtain the physical parameters of the jet. Spatial analysis revealed a continual contraction of the jet from the nozzle exit to the break-up zone. Fluctuations of the interface over time are characteristic of a random signal with a narrow bandpass. The Fourier transform of the different samples shows a bandpass of finite width centered around a characteristic frequency. The distribution of interface amplitude fluctuations was symmetrical to the average diameter, except in the zone in which the jet breaks up. By systematically tracing the main parameters of the jet diameter, we observed three zones with different jet behavior. The characteristic frequency of interface fluctuations increases as a linear function of the distance from the nozzle. The amplitude of interface fluctuations was an exponential function of the distance at which jet diameter fluctuations were measured.

  15. AIR DENSITY EFFECT ON THE ATOMIZATION OF LIQUID JETS IN CROSSFLOW

    Microsoft Academic Search

    A. BELLOFIORE; A. CAVALIERE; R. RAGUCCI

    2007-01-01

    An experimental study of liquid injection in a transverse airflow at high pressure and temperature was performed. Collected shadowgraphs were processed by image statistical analysis tools. The breakdown point location was correlated to liquid-to-gas momentum ratio, gas Reynolds number and aerodynamic Weber number. The substantial uniformity of behavior of the normalized jet trajectories allowed providing an empirical correlation validated in

  16. Characterisation of instabilities on the interface of coaxial jets of immiscible liquids with Laser Induced Fluorescence

    Microsoft Academic Search

    Georgios Charalampous; Yannis Hardalupas; Alex Taylor

    The early stages of the destabilisation of a round jet by a coaxial flow of an immiscible liquid within the bounds of an annulus are investigated in the vicinity of the central nozzle exit by visualising the flow by means of Planar Laser Induced Fluorescence (PLIF). The instabilities that develop at the interface of the two liquids close to the

  17. Analysis of liquid-metal-jet impingement cooling in a corner region and for a row of jets

    NASA Technical Reports Server (NTRS)

    Siegel, R.

    1975-01-01

    A conformal mapping method was used to analyze liquid-metal-jet impingement heat transfer. The jet flow region and energy equation are transformed to correspond to uniform flow in a parallel plate channel with nonuniform heat addition along a portion of one wall. The exact solution for the wall-temperature distribution was obtained in the transformed channel, and the results are mapped back into the physical plane. Two geometries are analyzed. One is for a single slot jet directed either into an interior corner formed by two flat plates, or over the external sides of the corner; the flat plates are uniformly heated, and the corner can have various included angles. The heat-transfer coefficient at the stagnation point at the apex of the plates is obtained as a function of the corner angle, and temperature distributions are calculated along the heated walls. The second geometry is an infinite row of uniformly spaced parallel slot jets impinging normally against a uniformly heated plate. The heat-transfer behavior is obtained as a function of the spacing between the jets. Results are given for several jet Peclet numbers from 5 to 50.

  18. Self-assembling of multi-jets by pyro-electrohydrodynamic effect for high throughput liquid nanodrops transfer.

    PubMed

    Coppola, Sara; Vespini, Veronica; Grilli, Simonetta; Ferraro, Pietro

    2011-10-01

    Destabilization of liquid film by electro-hydro-dynamics (EHD) pressure is achieved through the pyroelectric effect on a polar dielectric crystal. We show that by destabilizing the liquid film, periodical self-assembled multi-jets are obtained. The multi-jets operate simultaneously and could be exploited to dispense liquids with nanolitre drops. Such multiple self-assembled liquid jets have significant potential applicability for high-throughput liquid transfer by this novel pyro-EHD ink-jet approach. Since the method avoids the use of nozzles and electrodes, it is especially suitable for highly viscous liquids. Here we present and discuss the new multi-jet process and the results obtained with a liquid polymer (PDMS). PMID:21842042

  19. Production of jet fuel from coal-derived liquids

    Microsoft Academic Search

    M. W. Furlong; J. D. Fox; J. G. Masin; D. J. Soderberg

    1988-01-01

    Amoco and Lummus Crest, under a contract with the United States Department of Energy, are evaluating the process options and economics for upgrading the naphtha, crude phenols, and tar oil by-products from the Great Plains Coal Gasification Plant to jet fuels and other salable products. Task 1 of the work, in which processes to produce each of the three jet

  20. Experimental Investigation of Jet-Induced Mixing of a Large Liquid Hydrogen Storage Tank

    NASA Technical Reports Server (NTRS)

    Lin, C. S.; Hasan, M. M.; Vandresar, N. T.

    1994-01-01

    Experiments have been conducted to investigate the effect of fluid mixing on the depressurization of a large liquid hydrogen storage tank. The test tank is approximately ellipsoidal, having a volume of 4.89 m(exp 3) and an average wall heat flux of 4.2 W/m(exp 2) due to external heat input. A mixer unit was installed near the bottom of the tank to generate an upward directed axial jet flow normal to the liquid-vapor interface. Mixing tests were initiated after achieving thermally stratified conditions in the tank either by the introduction of hydrogen gas into the tank or by self-pressurization due to ambient heat leak through the tank wall. The subcooled liquid jet directed towards the liquid-vapor interface by the mixer induced vapor condensation and caused a reduction in tank pressure. Tests were conducted at two jet submergence depths for jet Reynolds numbers from 80,000 to 495,000 and Richardson numbers from 0.014 to 0.52. Results show that the rate of tank pressure change is controlled by the competing effects of subcooled jet flow and the free convection boundary layer flow due to external tank wall heating. It is shown that existing correlations for mixing time and vapor condensation rate based on small scale tanks may not be applicable to large scale liquid hydrogen systems.

  1. Experimental investigation on structures and velocity of liquid jets in a supersonic crossflow

    NASA Astrophysics Data System (ADS)

    Wang, Zhen-guo; Wu, Liyin; Li, Qinglian; Li, Chun

    2014-09-01

    Particle image velocimetry was applied in the study focusing on the structure and velocity of water jets injected into a Ma = 2.1 crossflow. The instantaneous structures of the jet, including surface waves in the near-injector region and vortices in the far-field, were visualized clearly. Spray velocity increases rapidly to 66% of the mainstream velocity in the region of x/d < 15, owing to the strong gas-liquid interaction near the orifice. By contrast, the velocity grows slowly in the far-field region, where the liquid inside the spray is accelerated mainly by the continuous driven force provided by the mainstream with the gas-liquid shear. The injection and atomization of liquid jet in a supersonic crossflow serves as a foundation of scramjet combustion process, by affecting the combustion efficiency and some other performances. With various forces acting on the liquid jet (Mashayek et al. [AIAA J. 46, 2674-2686 (2008)] and Wang et al. [AIAA J. 50, 1360-1366 (2012)]), the atomization process involves very complex flow physics. These physical processes include strong vortical structures, small-scale wave formation, stripping of small droplets from the jet surface, formations of ligaments, and droplets with a wide range of sizes.

  2. Hydrocarbon group type determination in jet fuels by high performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Antoine, A. C.

    1977-01-01

    Thirty-two jet and diesel fuel samples of varying chemical composition and physical properties were prepared from oil shale and coal syncrudes. Hydrocarbon types in these samples were determined by a fluorescent indicator adsorption analysis, and the results from three laboratories are presented and compared. Two methods of rapid high performance liquid chromatography were used to analyze some of the samples, and these results are also presented and compared. Two samples of petroleum-based Jet A fuel are similarly analyzed.

  3. Coaxial atomization of a round liquid jet in a high speed gas stream: A phenomenological study

    NASA Astrophysics Data System (ADS)

    Mayer, W. O. H.

    1994-05-01

    Coaxial injectors have proven to be advantageous for the injection, atomization and mixing of propellants in cryogenic H2/O2 rocket engines. Thereby, a round liquid oxygen jet is atomized by a fast, coaxial gaseous hydrogen jet. This article summarizes phenomenological studies of coaxial spray generation under a broad variation of influencing parameters including injector design, inflow, and fluid conditions. The experimental investigations, performed using spark light photography and high speed cinematography in a shadow graph setup as main diagnostic means, illuminate the most important processes leading to atomization. These are identified as turbulence in the liquid jet, surface instability, surface wave growth and droplet detachment. Numerical simulations including free surface flow phenomena are a further diagnostic tool to elucidate some atomization particulars. The results of the study are of general importance in the field of liquid atomization.

  4. Unsteady penetration of a target by a liquid jet

    PubMed Central

    Uth, Tobias; Deshpande, Vikram S.

    2013-01-01

    It is widely acknowledged that ceramic armor experiences an unsteady penetration response: an impacting projectile may erode on the surface of a ceramic target without substantial penetration for a significant amount of time and then suddenly start to penetrate the target. Although known for more than four decades, this phenomenon, commonly referred to as dwell, remains largely unexplained. Here, we use scaled analog experiments with a low-speed water jet and a soft, translucent target material to investigate dwell. The transient target response, in terms of depth of penetration and impact force, is captured using a high-speed camera in combination with a piezoelectric force sensor. We observe the phenomenon of dwell using a soft (noncracking) target material. The results show that the penetration rate increases when the flow of the impacting water jet is reversed due to the deformation of the jet–target interface––this reversal is also associated with an increase in the force exerted by the jet on the target. Creep penetration experiments with a constant indentation force did not show an increase in the penetration rate, confirming that flow reversal is the cause of the unsteady penetration rate. Our results suggest that dwell can occur in a ductile noncracking target due to flow reversal. This phenomenon of flow reversal is rather widespread and present in a wide range of impact situations, including water-jet cutting, needleless injection, and deposit removal via a fluid jet. PMID:24277818

  5. Unsteady penetration of a target by a liquid jet.

    PubMed

    Uth, Tobias; Deshpande, Vikram S

    2013-12-10

    It is widely acknowledged that ceramic armor experiences an unsteady penetration response: an impacting projectile may erode on the surface of a ceramic target without substantial penetration for a significant amount of time and then suddenly start to penetrate the target. Although known for more than four decades, this phenomenon, commonly referred to as dwell, remains largely unexplained. Here, we use scaled analog experiments with a low-speed water jet and a soft, translucent target material to investigate dwell. The transient target response, in terms of depth of penetration and impact force, is captured using a high-speed camera in combination with a piezoelectric force sensor. We observe the phenomenon of dwell using a soft (noncracking) target material. The results show that the penetration rate increases when the flow of the impacting water jet is reversed due to the deformation of the jet-target interface--this reversal is also associated with an increase in the force exerted by the jet on the target. Creep penetration experiments with a constant indentation force did not show an increase in the penetration rate, confirming that flow reversal is the cause of the unsteady penetration rate. Our results suggest that dwell can occur in a ductile noncracking target due to flow reversal. This phenomenon of flow reversal is rather widespread and present in a wide range of impact situations, including water-jet cutting, needleless injection, and deposit removal via a fluid jet. PMID:24277818

  6. Effect of liquid droplets on turbulence structure in a round gaseous jet

    SciTech Connect

    Mostafa, A.M.; Elghobashi, S.E.

    1984-04-01

    A proposed two equation turbulence model for incompressible dilute two phase flows was validated and extended for steady incompressible two phase flow including phase change. The model was tested for the flow of a turbulent axisymmetric gaseous jet laden with multisize evaporating liquid droplets. Predicted results include distributions of the mean velocity volume fractions of different phases concentration of the evaporated material in the carrier phase turbulence intensity and shear stress of the carrier phase droplet diameter distribution and the jet spreading rate. Results are analyzed based on a qualitative comparison with the corresponding single phase jet flow.

  7. Grenoble High Magnetic Field Laboratory Annual Report 2001 7.1. Liquid metal jet into a high

    E-print Network

    McDonald, Kirk

    /m: At velocities of 5 m/s a modification of the tip of the jet was observed for the highest gradient. No otherGrenoble High Magnetic Field Laboratory · Annual Report 2001 103 7.1. Liquid metal jet into a high the MHD effect on a pulsed mercury jet entering solenoidal field under an injection angle of 0° and 6

  8. Confined jet impingement of liquid nitrogen onto different heat transfer surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, P.; Xu, G. H.; Fu, X.; Li, C. R.

    2011-06-01

    Jet impingement of liquid nitrogen owns many applications in the cryogenic cooling aspects, such as, cooling of high-power chips in the electronic devices and cryoprobes in the cryosurgery. In the present study, we systematically investigated the confined jet impingement of liquid nitrogen from a tube of about 2.0 mm in diameter onto the heat transfer surfaces of about 5.0 mm in basement diameter with different heat transfer surface geometries and conditions, i.e., flat surface, hemispherical surface and flat surface with a needle. The effects of many influential factors, such as, the geometry of the heat transfer surface, jet velocity, distance between the nozzle exit and heat transfer surface, heat transfer surface condition, and some other, on the heat transfer were investigated. The heat transfer correlations were also proposed by using the experimental data, and it was found that the heat transfer mechanism of liquid impingement in the confined space was dominated by the convective evaporation rather than the nucleate boiling in the present case. The critical heat flux (CHF) of the confined jet impingement was measured and the visualization of the corresponding flow patterns of the confined jet impingement of liquid nitrogen was also conducted simultaneously to understand the heat transfer phenomena.

  9. Drop Size Distributions of Aerated Liquid Jets injected in Subsonic Crossflow

    NASA Astrophysics Data System (ADS)

    Adebayo, Adegboyega; Sallam, Khaled; Lin, Kuo-Cheng; Carter, Campbell

    2013-11-01

    An Experimental investigation of the breakup of aerated liquid jets in subsonic crossflow is described. Test conditions include crossflow Mach numbers of 0.3 and 0.6, Gas-to-liquid ratio of 0%, 4%, and 8%. Double pulsed digital holography was used to investigate the spray characteristics at downstream distances of 25, 50, and 100 jet diameters. The holograms are analyzed using image-processing algorithms to yield information about the drop sizes, drop velocities, and mass fluxes. Different drop size distributions are tested and compared including Rosin-Rammler distribution, log-normal distribution, and Simmons' universal root-normal distribution.

  10. Numerical investigation on the primary breakup of an inelastic non-Newtonian liquid jet with inflow turbulence

    NASA Astrophysics Data System (ADS)

    Zhu, Chengxiang; Ertl, Moritz; Weigand, Bernhard

    2013-08-01

    Direct Numerical Simulations of the primary breakup of an inelastic non-Newtonian liquid jet with inflow turbulence are presented in this paper. The jet's structure, surface behavior, non-Newtonian characteristics as well as its specific breakup mechanism are investigated and discussed. The shear thinning viscosity of the liquid phase plays an important role during jet injection resulting in circumferential rotation of interfacial waves. Streamwise contra-rotating vortex pairs as well as triple vortex structures are observed in the liquid phase. The local Ohnesorge number, which has a branch-structure distribution in the liquid phase before disintegration, is found to be 30% smaller in regions near the nozzle exit and in the shear layer than in the jet tip, suggesting a clear non-Newtonian influence. A cavity breakup mechanism for this type of non-Newtonian jet is identified and explained, giving a new perspective for jet disintegration analysis.

  11. Visualization of high speed liquid jet impaction on a moving surface.

    PubMed

    Guo, Yuchen; Green, Sheldon

    2015-01-01

    Two apparatuses for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device (for examining surface speeds between 0 and 25 m/sec) and a spinning disk device (for examining surface speeds between 15 and 100 m/sec). The air cannon linear traverse is a pneumatic energy-powered system that is designed to accelerate a metal rail surface mounted on top of a wooden projectile. A pressurized cylinder fitted with a solenoid valve rapidly releases pressurized air into the barrel, forcing the projectile down the cannon barrel. The projectile travels beneath a spray nozzle, which impinges a liquid jet onto its metal upper surface, and the projectile then hits a stopping mechanism. A camera records the jet impingement, and a pressure transducer records the spray nozzle backpressure. The spinning disk set-up consists of a steel disk that reaches speeds of 500 to 3,000 rpm via a variable frequency drive (VFD) motor. A spray system similar to that of the air cannon generates a liquid jet that impinges onto the spinning disc, and cameras placed at several optical access points record the jet impingement. Video recordings of jet impingement processes are recorded and examined to determine whether the outcome of impingement is splash, splatter, or deposition. The apparatuses are the first that involve the high speed impingement of low-Reynolds-number liquid jets on high speed moving surfaces. In addition to its rail industry applications, the described technique may be used for technical and industrial purposes such as steelmaking and may be relevant to high-speed 3D printing. PMID:25938331

  12. Observations of liquid jets injected into a highly accelerated supersonic boundary layer

    NASA Technical Reports Server (NTRS)

    Johnson, Arthur W.; Sreenivasan, K. R.

    1993-01-01

    Experiments were conducted to observe the cross-sectional structure and streamwise growth of round transverse liquid jets injected into a highly accelerated boundary layer in supersonic flow. The accompanying shock structure was also visualized. In one case, a round jet of acetone was injected into a fully turbulent Mach 2.5 boundary layer that was subsequently accelerated and partially laminarized through a sharp Prandtl-Meyer expansion corner. In the second case, a jet was injected into the laminarized Mach 3.2 boundary layer downstream of the expansion corner at the same jet-to-freestream momentum ratio. The jet and shock structure in both cases were visualized using schlieren optics. Wall-flow patterns were visualized using paints. It was found that the lateral spreading of jets injected downstream of the expansion fan was augmented close to the wall and had a cross-sectional structure significantly different from that of the jet injected upstream: the upstream jet spreads rapidly at the expansion corner in both the lateral and vertical directions.

  13. Role of surfactant in the breakup of liquid jets in food processing operations

    Microsoft Academic Search

    Sirichai Songsermpong

    2006-01-01

    The spontaneous break up into drops of a liquid jet is a fluid-dynamical process that impacts many important food and agricultural applications from spray drying of liquid foods and atomization of fertilizers and pesticides, to emerging applications such as protein micro-arraying and micro- and nano-encapsulation of flavors and nutrients. While the desired drop sizes differ widely among these applications, the

  14. Unsteady weakly perturbed motion of a body of revolution in a liquid with jet separation

    Microsoft Academic Search

    D. G. Shimkovich

    1983-01-01

    The unsteady weakly perturbed motion of a body in a liquid with jet separation has been investigated on various occasions in the twodimensional formulation [1–3]. The present paper gives a generalization of the formulation of this two-dimensional problem to the threedimensional case of flow past a body of revolution in accordance with Kirchhoff's scheme. A method is proposed for solving

  15. Nanoscale, Electrified Liquid Jets for High-Resolution Printing of Charge

    E-print Network

    Rogers, John A.

    Nanoscale, Electrified Liquid Jets for High-Resolution Printing of Charge Jang-Ung Park,,,| Sangkyu by electrohydrodynamics at micro- and nanoscale nozzles to print complex patterns of both positive and negative charges the basic aspects of this process and demonstrate the capabilities through printed patterns with diverse

  16. An electron jet pump: The Venturi effect of a Fermi liquid D. Taubert,1,a)

    E-print Network

    Ludwig-Maximilians-Universität, München

    An electron jet pump: The Venturi effect of a Fermi liquid D. Taubert,1,a) G. J. Schinner,1 C for electrons. Because of its phenomenological similarity we name the observed behavior the "electronic Venturi effect." VC 2011 American Institute of Physics. [doi:10.1063/1.3577959] I. INTRODUCTION The Venturi

  17. Flow patterns and cleaning behaviour of stationary horizontal liquid jets impinging on angled walls

    E-print Network

    Wang, Tao; Davidson, John F.; Wilson, D. Ian

    2014-09-30

    in warm reverse osmosis (RO) water, followed by a wash of 99.5% ACS reagent grade ethanol in de-ionised water (ratio 3:7 v/v), and finally with a wash of ?99.5 wt% ACS reagent grade acetone. MODELLING On a vertical wall, the liquid from the jet...

  18. A Particle-Tracking-Velocimetry (PTV) Investigation of Liquid Injection in a DC Plasma Jet

    NASA Astrophysics Data System (ADS)

    Damiani, David; Tarlet, Dominique; Meillot, Erick

    2014-02-01

    The present article describes experimental results of liquid injection in a thermal plasma jet by particle-tracking velocimetry (PTV). This technique delivers an in-situ real-time analysis of the liquid breakup and measures the velocities and the trajectories of the particles. The observations were done within the 10 mm surrounding the injection location where the plasma brightness is considerable. First, a validation of the proposed investigation method was carried out in a slower plasma jet. Subsequently, PTV measurements within faster plasma jets, resulting in a set of trajectories, were compared with trajectories achieved through optical diagnostics based on a simple shadow-graph technique proposed by Damiani et al. [Injection d'un liquide au sein d'un jet plasma thermique: optimisation de la trajectoire des particules, Proceedings of Congrès Francophone de Techniques Laser, CFTL 2010, Vandoeuvre lès nancy, France, 2010 (in French)]. These trajectories indicated that a higher plasma flow rate was required to spray all droplet sizes in the axis of the flow, thereby enabling an optimal spraying (then coating) application for producing nanostructured thin layers. This study showed that the liquid injection parameters are of main importance to obtain optimal injection and plasma parameters to achieve the required coating properties.

  19. Self-destabilizing mechanism of a laminar inviscid liquid jet issuing from a circular nozzle.

    PubMed

    Umemura, Akira

    2011-04-01

    A laminar inviscid liquid (typically water) jet issuing from a circular nozzle into otherwise quiescent air disintegrates into droplets periodically at a distance from the nozzle. The Plateau-Rayleigh instability theory and others cannot determine this breakup length because they do not have any logic that determines the initial amplitude of the unstable wave responsible for the breakup. In this paper, a closed spatial evolution solution is derived for a uniformly issued liquid jet by applying a theory that identifies the origin of the unstable wave. This solution describes the self-destabilizing mechanism of the liquid jet in the steady breakup state, showing that the initial amplitude of the unstable wave is determined by the capillary wave with upstream propagating speed that is created by the tip contraction at every breakup. Finally, the developed theory is extended to allow for the self-destabilizing mechanism of a liquid jet issuing from a long nozzle, which initially has a parabolic velocity profile and results in a long breakup length. PMID:21599295

  20. A focused liquid jet formed by a water hammer in a test tube

    E-print Network

    Kiyama, Akihito; Ando, Keita; Kameda, Masaharu

    2015-01-01

    We investigate motion of a gas-liquid interface in a test tube induced by a large acceleration via impulsive force. We conduct simple experiments in which the tube partially filled with a liquid falls under gravity and impacts a rigid floor. A curved gas-liquid interface inside the tube reverses and eventually forms an elongated jet (i.e. the so-called a focused jet). In our experiments, there arises either vibration of the interface or increment in the velocity of a liquid jet accompanied by the onset of cavitation in the liquid column. These phenomena cannot be explained by considering pressure impulse in a classical potential flow analysis, which does not account for finite speeds of sound as well as phase change. Here we model such water-hammer events as a result of one-dimensional pressure wave propagation and its interaction with boundaries through acoustic impedance mismatching. The method of characteristics is applied to describe pressure wave interactions and the subsequent cavitation. The proposed m...

  1. Application of molecular simulations: Insight into liquid bridging and jetting phenomena

    E-print Network

    I. Nezbeda; J. Jirsák; F. Mou?ka; W. R. Smith

    2015-04-03

    Molecular dynamics simulations have been performed on pure liquid water, aqueous solutions of sodium chloride, and polymer solutions exposed to a strong external electric field with the goal to gain molecular insight into the structural response to the field. Several simulation methodologies have been used to elucidate the molecular mechanisms of the processes leading to the formation of liquid bridges and jets (in the production of nanofibers). It is shown that in the established nanoscale structures, the molecules form a chain with their dipole moments oriented parallel to the applied field throughout the entire sample volume. The presence of ions may disturb this structure leading to its ultimate disintegration into droplets; the concentration dependence of the threshold field required to stabilize a liquid column has been determined. Conformational changes of the polymer in the jetting process have also been observed.

  2. The Plunge Phase of Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    McClure, John C.

    2005-01-01

    The many advantages of Friction Stir Welding have led to a relatively rapid acceptance in the often conservative welding community. Because the process is so different from traditional fusion welding, with which most investigators are most familiar, there remain many aspects of FSW for which there is no clear consensus. For example, the well known onion rings seen in transverse sections have been variously interpreted as grain size variations, variation in density of second phase particles and parts of the carousel of material rotating with the pin that have been shed from the carousel. Using Orientation Imaging Microscopy, Schneider has recently noted that the onion rings have a different orientation (and hence etch differently) than the surrounding material, and this orientation is consistent with slip plane orientations at the edge of the carousel. Likewise, the forces and torque exerted by the FSW tool on the work piece largely remain unaccounted for. Although these forces are routinely measured by investigators with commercial instrumented welders, they are rarely reported or even qualitatively analyzed. This paper will introduce a model based on a carousel or disk of material that rotates with the tool to estimate the torque and plunge force required to plunge a tool into the work piece. A stationary tool is modeled rather than the moving tool because effects such as thermal transients and metallurgical changes in the sample (primarily aging in aluminum) can be more easily accounted for. It is believed, however, that with some modifications the model should be applicable to a moving tool also.

  3. Traction Drive Inverter Cooling with Submerged Liquid Jet Impingement on Microfinned Enhanced Surfaces (Presentation)

    SciTech Connect

    Waye, S.; Narumanchi, S.; Moreno, G.

    2014-09-01

    Jet impingement is one means to improve thermal management for power electronics in electric-drive traction vehicles. Jet impingement on microfin-enhanced surfaces further augments heat transfer and thermal performance. A channel flow heat exchanger from a commercial inverter was characterized as a baseline system for comparison with two new prototype designs using liquid jet impingement on plain and microfinned enhanced surfaces. The submerged jets can target areas with the highest heat flux to provide local cooling, such as areas under insulated-gate bipolar transistors and diode devices. Low power experiments, where four diodes were powered, dissipated 105 W of heat and were used to validate computational fluid dynamics modeling of the baseline and prototype designs. Experiments and modeling used typical automotive flow rates using water-ethylene glycol as a coolant (50%-50% by volume). The computational fluid dynamics model was used to predict full inverter power heat dissipation. The channel flow and jet impingement configurations were tested at full inverter power of 40 to 100 kW (output power) on a dynamometer, translating to an approximate heat dissipation of 1 to 2 kW. With jet impingement, the cold plate material is not critical for the thermal pathway. A high-temperature plastic was used that could eventually be injection molded or formed, with the jets formed from a basic aluminum plate with orifices acting as nozzles. Long-term reliability of the jet nozzles and impingement on enhanced surfaces was examined. For jet impingement on microfinned surfaces, thermal performance increased 17%. Along with a weight reduction of approximately 3 kg, the specific power (kW/kg) increased by 36%, with an increase in power density (kW/L) of 12% compared with the baseline channel flow configuration.

  4. Primary breakup of a liquid jet in a transverse shock-induced flow

    NASA Astrophysics Data System (ADS)

    Ateshkadi, A.; Eastes, T. W.; Samuelsen, G. S.

    1993-06-01

    An imaging technique is used to investigate the fluid dynamics associated with the breakup of a liquid jet by a passing transverse shock wave. This mechanism is believed to be a potential source of combustion instability in liquid propellant rocket engines. Combustion instability is caused by the release of heat in phase with a passing pressure disturbance. The jet/wave interaction causes rapid atomization and propellant redistribution, and enhances mixing, vaporization, and reaction rates. Knowledge of the breakup process aids in prediction of local heat release with respect to the passing wave and provides insight on its viability as a potential instability mechanism. The present shock tube study applies high-speed, high-resolution photography to explore the jet/wave interaction that might be experienced in a large scale liquid oxygen/hydrogen (LOX/H2) engine similar to the SSME or other such engines being considered for the next generation of launch systems. Fluid parameters deemed important were simulated as well as possible. Time-resolved images of the jet/wave interaction indicate very rapid and fine atomization within 500 microsec of impingement.

  5. Capillary-dominated electrified jets of a viscous leaky dielectric liquid.

    PubMed

    Reznik, S N; Zussman, E

    2010-02-01

    The capillary-dominated regime of dynamics of electrified jets of a viscous leaky dielectric liquid is studied numerically. In this regime the effective force in the direction of an applied field due to tangential electric stresses is balanced by the gradient of liquid pressure governed by the surface-tension stresses. As is characteristic of this regime, the electric current and the characteristic jet radius are dependent on the surface-tension coefficient and not on viscosity. In the scope of this work, the conditions of the existence of this regime are determined. A qualitative order-of-magnitude analysis gives the power-law dependences of the jet radius and electric current on the parameters of the problem (conductivity, applied electric field, flow rate, and surface-tension coefficient). Numerical results are obtained for low conductive liquids for a large range of the dimensionless flow rate (capillary number, Ca). The order-of-magnitude estimations of electric current are in agreement with the numerical results given a small Ca. The corresponding numerically obtained jet shapes are discussed and explained. PMID:20365657

  6. Liquid jet breakup and atomization in rocket chambers under dense spray conditions

    NASA Technical Reports Server (NTRS)

    Kuo, Kenneth K.; Cheung, Fan-Bill; Woodward, Roger D.; Garner, Kenneth N.

    1991-01-01

    Two advanced diagnostic techniques were established and employed in this project. The first technique involves the use of a real-time x ray radiography system along with a high-speed CCD Xybion camera and an advanced digital image processor to investigate the breakup processes of the liquid core. The focus of this part of the project is to determine the inner structure of the liquid jet and via thin sheets of laser light, with the scatters light being photographed by a Xybion electronic camera synchronized to the laser pulse. This technique, which is capable of recording the breakup event occurring within 25 nano-seconds, enables us to freeze the motions of the jet and liquid droplets. The focus of this part of the project is to determine the outer structure of the liquid jet and to discover the configuration of the surface waves, the spray pattern, and the droplet size distribution in the non-dilute region. Results obtained by these two advanced diagnostic techniques will provide the much needed database for model development and accurate prediction of engine performance. The present work also represents a breakthrough in the area of advanced diagnostics of dense sprays.

  7. Direct numerical simulation of ignition in turbulent n-heptane liquid-fuel spray jets

    SciTech Connect

    Wang, Y.; Rutland, C.J. [Department of Mechanical Engineering, University of Wisconsin-Madison, WI 53706 (United States)

    2007-06-15

    Direct numerical simulation was used for fundamental studies of the ignition of turbulent n-heptane liquid-fuel spray jets. A chemistry mechanism with 33 species and 64 reactions was adopted to describe the chemical reactions. The Eulerian method is employed to solve the carrier-gas flow field and the Lagrangian method is used to track the liquid-fuel droplets. Two-way coupling interaction is considered through the exchange of mass, momentum, and energy between the carrier-gas fluid and the liquid-fuel spray. The initial carrier-gas temperature was 1500 K. Six cases were simulated with different droplet radii (from 10 to 30 {mu}m) and two initial velocities (100 and 150 m/s). From the simulations, it was found that evaporative cooling and turbulence mixing play important roles in the ignition of liquid-fuel spray jets. Ignition first occurs at the edges of the jets where the fuel mixture is lean, and the scalar dissipation rate and the vorticity magnitude are very low. For smaller droplets, ignition occurs later than for larger droplets due to increased evaporative cooling. Higher initial droplet velocity enhances turbulence mixing and evaporative cooling. For smaller droplets, higher initial droplet velocity causes the ignition to occur earlier, whereas for larger droplets, higher initial droplet velocity delays the ignition time. (author)

  8. Self-organization of jets in electrospinning from free liquid surface: A generalized approach

    NASA Astrophysics Data System (ADS)

    Lukas, David; Sarkar, Arindam; Pokorny, Pavel

    2008-04-01

    Electrospinning has enabled creation of excellent materials for a great number of applications. Previously, it was based on less productive capillary spinners. The present study is based on recent efforts to elevate electrospinning technology to an industrial level by simultaneously provoking innumerable polymeric jets from a sufficiently large liquid surface to increase productivity. Particularly, it deals with electrospinning from free surface of conductive liquids and validates a formulated hypothesis that explains self-organization of jets on one-dimensional free liquid surfaces in terms of electrohydrodynamic instability of surface waves. Here, it is shown how the hypothesis, based on a profound analysis of a dispersion law, explains that above a certain critical value of applied electric field intensity/field strength the system starts to be self-organized in mesocopic scale due to the mechanism of the "fastest forming instability." The mechanism plays a key role in selecting a particular wave with a characteristic wavelength whose amplitude boundlessly grows faster than the others. The fastest growing stationary wave, according to the hypothesis, marks the onset of electrospinning from a free liquid surface with its jets originating from the wave crests. Singularity of this approach lies in predicting critical values of the phenomenon, viz., critical field strength and corresponding critical interjet distance. The critical field strength, will, thereafter, be used in defining a unique dimensionless electrospinning number. It will, subsequently, be shown how the critical interjet distance, i.e., the maximal distance between the neighboring jets, simply depends on the capillary length. The capillary length represents a latent characteristic spatial scale of the system. The theory also predicts interjet distance for field strengths above the critical value. The said prediction is universally applicable for all conductive liquids if it is expressed in terms of the dimensionless parameters of the interjet distance and the electrospinning number. The theory also predicts relaxation time, necessary for spontaneous jetting after a high voltage is applied. The theoretical considerations are eventually compared to that of Zeleny's, obtained for capillary electrospinner to demonstrate universality of the approach. Eventually, jetting from free liquid surface on specially designed linear cleft electrospinner are observed, analyzed, and compared to the theoretical predictions obtaining satisfactory results.

  9. Experimental investigation of the thermal-hydraulics of gas jet expansion In a two-dimensional liquid pool

    E-print Network

    Rothrock, Ray Alan

    1978-01-01

    Gas jet blowdown in a two-dimensional liquid pool has been experimentally investigated. Two sets of experiments were performed: a set of hydrodynamic experiments, where a non-condensible gas is injected into a subcooled ...

  10. Emission of drops from the tip of an electrified jet of an inviscid liquid of infinite electrical conductivity

    Microsoft Academic Search

    F. J. Higuera; E. T. S. Ingenieros; Cardenal Cisneros

    2007-01-01

    A numerical description is presented of the emission of drops from the tip of a long axisymmetric jet, which may develop when an inviscid liquid of infinite electrical conductivity is injected into a dielectric medium under the action of a strong electric field. The applied field is intensified by the presence of the equipotential surface of the jet, leading to

  11. Investigation on cone jetting regimes of liquid droplets subjected to pyroelectric fields induced by laser blasts

    NASA Astrophysics Data System (ADS)

    Gennari, Oriella; Battista, Luigi; Silva, Benjamin; Grilli, Simonetta; Miccio, Lisa; Vespini, Veronica; Coppola, Sara; Orlando, Pierangelo; Aprin, Laurent; Slangen, Pierre; Ferraro, Pietro

    2015-02-01

    Electrical conductivity and viscosity play a major role in the tip jetting behaviour of liquids subjected to electrohydrodynamic (EHD) forces, thus influencing significantly the printing performance. Recently, we developed a nozzle- and electrode-free pyro-EHD system as a versatile alternative to conventional EHD configurations and we demonstrated different applications, including inkjet printing and three-dimensional lithography. However, only dielectric fluids have been used in all of those applications. Here, we present an experimental characterization of the pyro-EHD jetting regimes, induced by laser blasts, of sessile drops in case of dielectric and conductive liquids in order to extend the applicability of the system to a wider variety of fields including biochemistry and biotechnology where conductive aqueous solutions are typically used.

  12. Numerical studies of the effects of jet-induced mixing on liquid-vapor interface condensation

    NASA Technical Reports Server (NTRS)

    Lin, Chin-Shun

    1989-01-01

    Numerical solutions of jet-induced mixing in a partially full cryogenic tank are presented. An axisymmetric laminar jet is discharged from the central part of the tank bottom toward the liquid-vapor interface. Liquid is withdrawn at the same volume flow rate from the outer part of the tank. The jet is at a temperature lower than the interface, which is maintained at a certain saturation temperature. The interface is assumed to be flat and shear-free and the condensation-induced velocity is assumed to be negligibly small compared with radial interface velocity. Finite-difference method is used to solve the nondimensional form of steady state continuity, momentum, and energy equations. Calculations are conducted for jet Reynolds numbers ranging from 150 to 600 and Prandtl numbers ranging from 0.85 to 2.65. The effects of above stated parameters on the condensation Nusselt and Stanton numbers which characterize the steady-state interface condensation process are investigated. Detailed analysis to gain a better understanding of the fundamentals of fluid mixing and interface condensation is performed.

  13. Vapor condensation at the free surface of an axisymmetric liquid mixed by a laminar jet

    NASA Technical Reports Server (NTRS)

    Lin, Chin-Shun

    1991-01-01

    This paper presents numerical solutions of jet-induced mixing in a partially full cryogenic tank. An axisymmetric laminar jet is discharged from the central part of the tank bottom toward the liquid-vapor interface. Liquid is withdrawn at the same volume flow rate from the outer part of the tank. The jet is at a temperature lower than the interface, which is maintained at a certain saturation temperature. The interface is assumed to be flat and shear free and the condensation-induced velocity is assumed to be negligibly small compared with radial interface velocity. Finite-difference method is used to slove the nondimensional form of steady-state continuity, momentum, and energy equations. Calculations are conducted for jet Reynolds numbers ranging from 150 to 600 and Prandtl numbers ranging from 0.85 to 2.65. The effects of previously stated parameters on the condensation Nusselt and Stanton numbers that characterize the steady-state interface condensation process are investigated. Detailed analysis is performed to gain a better understanding of the fundamentals of fluid mixing and interface condensation.

  14. Capillary and acceleration wave breakup of liquid jets in axial-flow airstreams

    NASA Technical Reports Server (NTRS)

    Ingebo, R. D.

    1981-01-01

    Empirical correlations of reciprocal mean drop diameter with airstream momentum were derived from capillary and acceleration wave breakup of liquid jets atomized by cross stream injection into axial flow airstreams. A scanning radiometer was used to obtain data over an airstream momentum range of 3.7 to 25.7 g/sq cm sec. Transition from capillary to acceleration wave breakup was obtained at a critical Weber-Reynolds number of 1,000,000.

  15. Liquid-jet laser–plasma extreme ultraviolet sources: from droplets to filaments

    Microsoft Academic Search

    Björn A M Hansson; Hans M Hertz

    2004-01-01

    The laser plasma is one of the major contenders as a high-power source for future high-volume-manufacturing extreme ultraviolet lithography systems. Such laser–plasma sources require a target system that allows high-repetition-rate operation with low debris and manageable thermal load at the required high laser power. In this paper, we review the development of the liquid-jet target laser plasmas, from droplets to

  16. Journal of Fluid Mechanics Plunging cavities

    E-print Network

    Boyer, Edmond

    interesting links with other transient cavities. Key words: bubble dynamics, free-surface flows, jets, wave breaking 1. Introduction Water waves break in a wide range of conditions (Battjes 1988; Banner & Peregrine from Zhu, Oguz & Prosperetti (2000), a vertical cylindrical water jet of diameter Dj = 5.4 mm

  17. Laser fragmentation of organic microparticles into colloidal nanoparticles in a free liquid jet

    NASA Astrophysics Data System (ADS)

    Wagener, Philipp; Barcikowski, Stephan

    2010-11-01

    We present a novel approach for laser fragmentation of melamine cyanurate microcrystals suspended in liquid into colloidal nanoparticles. Laser fragmentation is done by irradiating a liquid jet of melamine cyanurate suspended in water with intense picosecond pulses. The free liquid jet is generated by a nozzle with small diameter and provides a thin liquid filament ( d fil<1 mm) perpendicular to the focused laser beam. This geometry allows tight focusing resulting in high intensities without the danger of damaging an optical element like windows necessary in conventional flow cells or cuvettes. It reduces losses of excitation light by avoiding scattering or absorption in front of the focus. We stabilized the nanoparticles electrosterically in-situ with neutral and polyelectrolytic polymers preventing agglomeration and precipitation. The threshold for sufficient stabilization of laser-fragmented nanoparticles ( d hydrodyn?200 nm) is reached at a mass fraction of 0.25 wt% dextrin as a neutral polymer and 0.01 wt% polyacrylic acid as a polyelectrolytic polymer. Hydrodynamic size and zeta-potential of the nanoparticles can be controlled by mass fraction of the stabilization agent.

  18. Thorough small-angle X-ray scattering analysis of the instability of liquid micro-jets in air.

    PubMed

    Marmiroli, Benedetta; Cacho-Nerin, Fernando; Sartori, Barbara; Pérez, Javier; Amenitsch, Heinz

    2014-01-01

    Liquid jets are of interest, both for their industrial relevance and for scientific applications (more important, in particular for X-rays, after the advent of free-electron lasers that require liquid jets as sample carrier). Instability mechanisms have been described theoretically and by numerical simulation, but confirmed by few experimental techniques. In fact, these are mainly based on cameras, which is limited by the imaging resolution, and on light scattering, which is hindered by absorption, reflection, Mie scattering and multiple scattering due to complex air/liquid interfaces during jet break-up. In this communication it is demonstrated that synchrotron small-angle X-ray scattering (SAXS) can give quantitative information on liquid jet dynamics at the nanoscale, by detecting time-dependent morphology and break-up length. Jets ejected from circular tubes of different diameters (100-450?µm) and speeds (0.7-21?m?s(-1)) have been explored to cover the Rayleigh and first wind-induced regimes. Various solvents (water, ethanol, 2-propanol) and their mixtures have been examined. The determination of the liquid jet behaviour becomes essential, as it provides background data in subsequent studies of chemical and biological reactions using SAXS or X-ray diffraction based on synchrotron radiation and free-electron lasers. PMID:24365936

  19. Direct numerical simulations of temporally developing turbulent reacting liquid-fueled jets

    NASA Astrophysics Data System (ADS)

    Shashank, Shashank; Pitsch, Heinz

    2012-11-01

    Liquid fueled engines are ubiquitous in the transportation industry because liquid fuel minimizes the weight and volume of propulsion systems. The combustion that occurs in these engines is an inherently multi-physics process, involving fuel evaporation, reaction kinetics, and high levels of turbulence. A desire for high fidelity data that explains complex interaction between different physical mechanisms motivates the consideration of direct numerical simulation (DNS) as an investigation tool. In this study three-dimensional DNS of a reacting n-heptane liquid fueled temporal jet have been performed to study auto-ignition and subsequent burning in conditions that are representative of a diesel engine environment. In these simulations the continuous phase is described using an Eulerian representation whereas Lagrangian particle tracking is used to model the dispersed phase. The results of this study will demonstrate the importance of unsteady effects, and of accounting for the interaction between different modes of combustion, when simulating spray combustion.

  20. Periodically plunging foil near a free surface

    NASA Astrophysics Data System (ADS)

    Cleaver, D. J.; Calderon, D. E.; Wang, Z.; Gursul, I.

    2013-03-01

    Experiments were performed to investigate the effects of amplitude and depth on the drag reduction of a NACA 0012 airfoil plunging near a free surface for a range of frequencies. Beyond the effect of the free surface, at low Strouhal numbers based on amplitude, Sr A, the drag reduction follows a parabolic trend with greater effect for greater amplitude, similar to the Garrick predictions. At Sr A ? 0.08, larger amplitudes break from this trend due to leading-edge vortex formation. As a result, smaller amplitudes become preferable for Sr A > 0.12. In addition, for the first time, vortex lock-in is documented experimentally. The effect of depth is twofold; firstly with decreasing depth, there is a general departure from the Garrick trends. Secondly, a reduction in thrust is observed around a constant unsteady parameter of ? = U ? 2 ?f/ g ? 0.25; around this value significant free-surface waves form that detract from thrust creation. For depths greater than two chord lengths, there is negligible free-surface effect.

  1. Impact of plunging breaking waves on a partially submerged cube

    NASA Astrophysics Data System (ADS)

    Wang, A.; Ikeda, C.; Duncan, J. H.

    2013-11-01

    The impact of a deep-water plunging breaking wave on a partially submerged cube is studied experimentally in a tank that is 14.8 m long and 1.2 m wide with a water depth of 0.91 m. The breakers are created from dispersively focused wave packets generated by a programmable wave maker. The water surface profile in the vertical center plane of the cube is measured using a cinematic laser-induced fluorescence technique with movie frame rates ranging from 300 to 4,500 Hz. The pressure distribution on the front face of the cube is measured with 24 fast-response sensors simultaneously with the wave profile measurements. The cube is positioned vertically at three heights relative to the mean water level and horizontally at a distance from the wave maker where a strong vertical water jet is formed. The portion of the water surface between the contact point on the front face of the cube and the wave crest is fitted with a circular arc and the radius and vertical position of the fitted circle is tracked during the impact. The vertical acceleration of the contact point reaches more than 50 times the acceleration of gravity and the pressure distribution just below the free surface shows a localized high-pressure region with a very high vertical pressure gradient. The impact of a deep-water plunging breaking wave on a partially submerged cube is studied experimentally in a tank that is 14.8 m long and 1.2 m wide with a water depth of 0.91 m. The breakers are created from dispersively focused wave packets generated by a programmable wave maker. The water surface profile in the vertical center plane of the cube is measured using a cinematic laser-induced fluorescence technique with movie frame rates ranging from 300 to 4,500 Hz. The pressure distribution on the front face of the cube is measured with 24 fast-response sensors simultaneously with the wave profile measurements. The cube is positioned vertically at three heights relative to the mean water level and horizontally at a distance from the wave maker where a strong vertical water jet is formed. The portion of the water surface between the contact point on the front face of the cube and the wave crest is fitted with a circular arc and the radius and vertical position of the fitted circle is tracked during the impact. The vertical acceleration of the contact point reaches more than 50 times the acceleration of gravity and the pressure distribution just below the free surface shows a localized high-pressure region with a very high vertical pressure gradient. This work is supported by the Office of Naval Research under grant N000141110095.

  2. Liquid and gelled sprays for mixing hypergolic propellants using an impinging jet injection system

    NASA Astrophysics Data System (ADS)

    James, Mark D.

    The characteristics of sprays produced by liquid rocket injectors are important in understanding rocket engine ignition and performance. The includes, but is not limited to, drop size distribution, spray density, drop velocity, oscillations in the spray, uniformity of mixing between propellants, and the spatial distribution of drops. Hypergolic ignition and the associated ignition delay times are also important features in rocket engines, providing high reliability and simplicity of the ignition event. The ignition delay time is closely related to the level and speed of mixing between a hypergolic fuel and oxidizer, which makes the injection method and conditions crucial in determining the ignition performance. Although mixing and ignition of liquid hypergolic propellants has been studied for many years, the processes for injection, mixing, and ignition of gelled hypergolic propellants are less understood. Gelled propellants are currently under investigation for use in rocket injectors to combine the advantages of solid and liquid propellants, although not without their own difficulties. A review of hypergolic ignition has been conducted for selected propellants, and methods for achieving ignition have been established. This research is focused on ignition using the liquid drop-on-drop method, as well as the doublet impinging jet injector. The events leading up to ignition, known as pre-ignition stage are discussed. An understanding of desirable ignition and combustion performance requires a study of the effects of injection, temperature, and ambient pressure conditions. A review of unlike-doublet impinging jet injection mixing has also been conducted. This includes mixing factors in reactive and non-reactive sprays. Important mixing factors include jet momentum, jet diameter and length, impingement angle, mass distribution, and injector configuration. An impinging jet injection system is presented using an electro-mechanically driven piston for injecting liquid and gelled hypergolic propellants. A calibration of the system is done with water in preparation for hypergolic injection, and characteristics of individual water and gelled JP-8 jets are studied at velocities in the range of 3 ft/s to 61 ft/s. The piston response is also analyzed to characterize the startup and steady state liquid jet velocities using orifices of 0.02" in diameter. Using this injection system, water and gelled JP-8 sprays are formed and compared across injection velocities of 30 ft/s to 121 ft/s. The comparison includes sheet shape and disintegration, total number of drops, drop size distributions, drop eccentricity, most populated drop bin size, and mean drop sizes. A test matrix for investigating the effects of mixing on ignition of MMH and IRFNA through different injection conditions are presented. First, water and IRFNA are injected to create a spray in the combustion chamber in order to verify effectiveness of test procedures and the test hardware. Next, injection of the hypergolic propellants MMH and IRFNA are done in accordance to the test matrix, although ignition was not observed as expected. These injections are followed by simple drop-on-drop tests to investigate propellant quality and ignition delay. Drop tests are performed with propellants IRFNA/MMH, and again with H2O2/Block 0 as possible propellant replacements for the proposed test plan.

  3. High Resolution Spectroscopy and Dynamics: from Jet Cooled Radicals to Gas-Liquid Interfaces

    NASA Astrophysics Data System (ADS)

    Sharp-Williams, E.; Roberts, M. A.; Roscioli, J. R.; Gisler, A. W.; Ziemkiewicz, M.; Nesbitt, D. J.; Dong, F.; Perkins, B. G., Jr.

    2010-06-01

    This talk will attempt to reflect recent work in our group involving two quite different but complementary applications of high resolution molecular spectroscopy for detailed study of intramolecular as well as intermolecular dynamics in small molecules. The first is based on direct infrared absorption spectroscopy in a 100 KHz slit supersonic discharge, which provides a remarkably versatile and yet highly sensitive probe for study of important chemical transients such as open shell combustion species and molecular ions under jet cooled (10-20K), sub-Doppler conditions. For this talk will focus on gas phase spectroscopic results for a series of unsaturated hydrocarbon radical species (ethynyl, vinyl, and phenyl) reputed to be critical intermediates in soot formation. Secondly, we will discuss recent applications of high resolution IR and velocity map imaging spectroscopy toward quantum state resolved collision dynamics of jet cooled molecules from gas-room temperature ionic liquid (RTIL) and gas-self assembled monolayer (SAM) interfaces. Time permitting, we will also present new results on hyperthermal scattering of jet cooled NO radical from liquid Ga, which offer a novel window into non-adiabatic energy transfer and electron-hole pair dynamics at the gas-molten metal interface.

  4. Liquid helium inertial jet for comparative study of classical and quantum turbulence.

    PubMed

    Duri, D; Baudet, C; Charvin, P; Virone, J; Rousset, B; Poncet, J-M; Diribarne, P

    2011-11-01

    We present a new cryogenic wind tunnel facility developed to study the high Reynolds number developed classical or quantum turbulence in liquid (4)He. A stable inertial round jet flow with a Reynolds number of 4 × 10(6) can be sustained in both He I and He II down to a minimum temperature of 1.7 K. The circuit can be pressurized up to 3.5 × 10(5) Pa. The system has been designed to exploit the self-similar properties of the jet far field in order to adapt to the spatial resolution of the existing probes. Multiple and complementary sensors can be simultaneously installed to obtain spatial and time resolved measurements. The technical difficulties and design details are described and the system performance is presented. PMID:22129015

  5. Hydrocarbon group type determination in jet fuels by high performance liquid chromatography

    NASA Technical Reports Server (NTRS)

    Antoine, A. C.

    1977-01-01

    Results are given for the analysis of some jet and diesel fuel samples which were prepared from oil shale and coal syncrudes. Thirty-two samples of varying chemical composition and physical properties were obtained. Hydrocarbon types in these samples were determined by fluorescent indicator adsorption (FIA) analysis, and the results from three laboratories are presented and compared. Recently, rapid high performance liquid chromatography (HPLC) methods have been proposed for hydrocarbon group type analysis, with some suggestion for their use as a replacement of the FIA technique. Two of these methods were used to analyze some of the samples, and these results are also presented and compared. Two samples of petroleum-based Jet A fuel are similarly analyzed.

  6. Gas-phase flowrate effect on disintegrating cryogenic liquid-jets

    NASA Technical Reports Server (NTRS)

    Ingebo, Robert D.

    1990-01-01

    Two phase liquid and gaseous nitrogen flow in a pneumatic two fluid atomizer was investigated. Characteristic dropsize for cryogenic sprays were measured with a scattered light scanning instrument developed at NASA-Lewis. Tests were conducted primarily in the aerodynamic stripping regime of liquid jet atomization. At a sampling distance of bar-x =1.3 cm, the Sauter mean, D(sub 32), and volume median, D(sub v.5), drop diameters were measured and correlated with nitrogen gas flowrate, W(sub n), to give the following expressions: D sub 32 to the -1=210W(sub n) to the -1.33 and D(sub v.5) to the -1=150 W(sub n to the -1.33, where reciprocal diameters and gas flowrate are in cm (-1) and g/sec, respectively. The exponent 1.33 for nitrogen gas flowrate, W(sub n), is the same as that predicted by atomization theory for liquid-jet breakup in high velocity gasflow. When the spray was sampled at axial distances of bar-x=2.5 and 4.5 cm downstream of the atomizer, the exponent decreased to 1.2 and 0.9, respectively. This was attributed to the loss of small droplets due to their rapid vaporization.

  7. On the absence of asymmetric wakes for periodically plunging finite wings

    NASA Astrophysics Data System (ADS)

    Calderon, D. E.; Cleaver, D. J.; Gursul, I.; Wang, Z.

    2014-07-01

    It has previously been shown that, at high Strouhal numbers, oscillating airfoils can produce deflected jets that can create very high lift-coefficients for otherwise symmetric scenarios. These deflected jets form through pairing of the trailing-edge vortices to create asymmetric vortex couples that self-propel at an angle to the freestream, resulting in an asymmetric flow field and non-zero lift. In this paper results are presented that indicate these high-lift deflected jets cannot form for finite wings. Instead of the straight vortex tubes that pair and convect at an angle to the freestream observed for effectively infinite wings, finite wings exhibit vortex tubes that break into two branches near the tip forming double helix structures. One branch connects with the last vortex; one branch connects with the next vortex. This creates a long "daisy chain" of interconnected trailing edge vortices forming a long series of vortex loops. These symmetric flow fields are shown to persist for finite wings even to Strouhal numbers more than twice those required to produce asymmetric wakes on plunging airfoils. Two contributing reasons are discussed for why deflected jets are not observed. First the tip vortex creates three-dimensionality that discourages vortex coupling. Second, the symmetry of the circulation of the interconnected vortex loops, which has been confirmed by the experiments, is a natural consequence of the vortex topology. Therefore, the asymmetry in trailing edge vortex strength previously observed as characteristic of deflected jets cannot be supported for finite wings.

  8. A ballistic compressor-based experiment for the visualization of liquid propellant jet combustion above 100 MPa

    Microsoft Academic Search

    A. Birk; D. E. Kooker

    1998-01-01

    This paper describes the components and operation of an experimental setup for the visualization of liquid propellant (LP)\\u000a jet combustion at pressures above 100?MPa. The apparatus consists of an in-line ballistic compressor and LP injector. The\\u000a ballistic compressor, based on a modified 76?mm gun, provides high-pressure (ca. 55?MPa) clear hot gas for the jet ignition.\\u000a A piston (projectile) is fired

  9. High-power liquid-lithium jet target for neutron production

    E-print Network

    Halfon, S; Kijel, D; Paul, M; Berkovits, D; Eliyahu, I; Feinberg, G; Friedman, M; Hazenshprung, N; Mardor, I; Nagler, A; Shimel, G; Tessler, M; Silverman, I

    2013-01-01

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the 7Li(p,n)7Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy (BNCT). The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm3) with fast transport. The target was designed based on a thermal model, accompanied by a detailed calculation of the 7Li(p,n) neutron yield, energy distribution and angular distribution. Liquid lithium is circulated through the target loop at ~200oC and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can diss...

  10. Production of jet fuels from coal-derived liquids. Volume 3. Jet fuels potential of liquid by-products from the Great Plains Gasification Project. Interim report, September 1986December 1987

    Microsoft Academic Search

    E. B. Smith; F. D. Guffey; L. G. Nickerson

    1988-01-01

    Three liquid by-products from the Great Plains Gasification Project, tar oil crude phenols, and naptha, were evaluated as potential sources of military jet fuels. Tar oil, produced at about 3200 barrels per day (BPD), is a highly aromatic lignite-pyrolysis liquid with a typical density of 1.01 and boiling range of about 220-975 F (104-524). Crude phenols, extracted from process water

  11. Ultraviolet vision and foraging in dip and plunge diving birds

    PubMed Central

    Håstad, Olle; Ernstdotter, Emma; Ödeen, Anders

    2005-01-01

    Many fishes are sensitive to ultraviolet (UV) light and display UV markings during courtship. As UV scatters more than longer wavelengths of light, these signals are only effective at short distances, reducing the risk of detection by swimming predators. Such underwater scattering will be insignificant for dip and plunge diving birds, which prey on fishes just below the water surface. One could therefore expect to find adaptations in the eyes of dip and plunge diving birds that tune colour reception to UV signals. We used a molecular method to survey the colour vision tuning of five families of dip or plunge divers and compared the results with those from sister taxa of other foraging methods. We found evidence of extended UV vision only in gulls (Laridae). Based on available evidence, it is more probable that this trait is associated with their terrestrial foraging habits rather than piscivory. PMID:17148194

  12. Extensional flow of liquid jets formed by bubble collapse in oils under cavitation-generated pressure waves

    NASA Astrophysics Data System (ADS)

    Barrow, M. S.; Brown, S. W. J.; Williams, P. R.

    We report a study of liquid jets which are formed by bubble collapse under cavitation-generated pressure waves. The results obtained for jets formed from samples of a multigrade motor oil provide the first evidence that such jets experience a significant degree of extensional deformation, at high rates of extension. The results support the conclusion that the reduced velocity and final length of such jets, relative to their Newtonian counterparts, is due to an increased resistance to extensional flow. Insofar as the multigrade oils studied here are made viscoelastic by polymer additives and evidently possess significant levels of resistance to extension, the results provide evidence in support of a mitigating effect of viscoelasticity on a cavitation damage mechanism, as mooted by Berker et al. (J Non Newton Fluid Mech 56:333, 1995).

  13. Even contact design for the plunge shaving cutter

    Microsoft Academic Search

    Ruei-Hung Hsu; Zhang-Hua Fong

    2010-01-01

    Gear shaving is a highly efficient and economical cutting method in gear finishing. The tooth profile of the plunge shaving cutter is usually sharpened by a cone grinding wheel on the cutter resharpening machine. The resulting radial prestressing force between the work gear and shaving cutter is constant in the final stage of the shaving process. Assuming that the cutting

  14. Deposition of micron liquid droplets on wall in impinging turbulent air jet

    NASA Astrophysics Data System (ADS)

    Liu, Tianshu; Nink, Jacob; Merati, Parviz; Tian, Tian; Li, Yong; Shieh, Tom

    2010-06-01

    The fluid mechanics of the deposition of micron liquid (olive oil) droplets on a glass wall in an impinging turbulent air jet is studied experimentally. The spatial patterns of droplets deposited on a wall are measured by using luminescent oil visualization technique, and the statistical data of deposited droplets are obtained through microscopic imagery. Two distinct rings of droplets deposited on a wall are found, and the mechanisms of the formation of the inner and outer rings are investigated based on global diagnostics of velocity and skin friction fields. In particular, the intriguing effects of turbulence, including large-scale coherent vortices and small-scale random turbulence, on micron droplet deposition on a wall and coalescence in the air are explored.

  15. High-power liquid-lithium jet target for neutron production

    NASA Astrophysics Data System (ADS)

    Halfon, S.; Arenshtam, A.; Kijel, D.; Paul, M.; Berkovits, D.; Eliyahu, I.; Feinberg, G.; Friedman, M.; Hazenshprung, N.; Mardor, I.; Nagler, A.; Shimel, G.; Tessler, M.; Silverman, I.

    2013-12-01

    A compact liquid-lithium target (LiLiT) was built and tested with a high-power electron gun at the Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the 7Li(p,n)7Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy. The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm3) with fast transport. The target was designed based on a thermal model, accompanied by a detailed calculation of the 7Li(p,n) neutron yield, energy distribution, and angular distribution. Liquid lithium is circulated through the target loop at ˜200 °C and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power areal densities of >4 kW/cm2 and volume power density of ˜2 MW/cm3 at a lithium flow of ˜4 m/s while maintaining stable temperature and vacuum conditions. The LiLiT setup is presently in online commissioning stage for high-intensity proton beam irradiation (1.91-2.5 MeV, 1-2 mA) at SARAF.

  16. High-power liquid-lithium jet target for neutron production

    E-print Network

    S. Halfon; A. Arenshtam; D. Kijel; M. Paul; D. Berkovits; I. Eliyahu; G. Feinberg; M. Friedman; N. Hazenshprung; I. Mardor; A. Nagler; G. Shimel; M. Tessler; I. Silverman

    2013-11-30

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the 7Li(p,n)7Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy (BNCT). The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm3) with fast transport. The target was designed based on a thermal model, accompanied by a detailed calculation of the 7Li(p,n) neutron yield, energy distribution and angular distribution. Liquid lithium is circulated through the target loop at ~200oC and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power areal densities of > 4 kW/cm2 and volume power density of ~ 2 MW/cm3 at a lithium flow of ~4 m/s while maintaining stable temperature and vacuum conditions. The LiLiT setup is presently in online commissioning stage for high-intensity proton beam irradiation (1.91- 2.5 MeV, 1-2 mA) at SARAF.

  17. High-power liquid-lithium jet target for neutron production.

    PubMed

    Halfon, S; Arenshtam, A; Kijel, D; Paul, M; Berkovits, D; Eliyahu, I; Feinberg, G; Friedman, M; Hazenshprung, N; Mardor, I; Nagler, A; Shimel, G; Tessler, M; Silverman, I

    2013-12-01

    A compact liquid-lithium target (LiLiT) was built and tested with a high-power electron gun at the Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the (7)Li(p,n)(7)Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy. The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm(3)) with fast transport. The target was designed based on a thermal model, accompanied by a detailed calculation of the (7)Li(p,n) neutron yield, energy distribution, and angular distribution. Liquid lithium is circulated through the target loop at ~200 °C and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power areal densities of >4 kW/cm(2) and volume power density of ~2 MW/cm(3) at a lithium flow of ~4 m/s while maintaining stable temperature and vacuum conditions. The LiLiT setup is presently in online commissioning stage for high-intensity proton beam irradiation (1.91-2.5 MeV, 1-2 mA) at SARAF. PMID:24387433

  18. High-power liquid-lithium jet target for neutron production

    SciTech Connect

    Halfon, S.; Feinberg, G. [Soreq NRC, Yavne 81800 (Israel) [Soreq NRC, Yavne 81800 (Israel); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Arenshtam, A.; Kijel, D.; Berkovits, D.; Eliyahu, I.; Hazenshprung, N.; Mardor, I.; Nagler, A.; Shimel, G.; Silverman, I. [Soreq NRC, Yavne 81800 (Israel)] [Soreq NRC, Yavne 81800 (Israel); Paul, M.; Friedman, M.; Tessler, M. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)] [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)

    2013-12-15

    A compact liquid-lithium target (LiLiT) was built and tested with a high-power electron gun at the Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the {sup 7}Li(p,n){sup 7}Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy. The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm{sup 3}) with fast transport. The target was designed based on a thermal model, accompanied by a detailed calculation of the {sup 7}Li(p,n) neutron yield, energy distribution, and angular distribution. Liquid lithium is circulated through the target loop at ?200 °C and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power areal densities of >4 kW/cm{sup 2} and volume power density of ?2 MW/cm{sup 3} at a lithium flow of ?4 m/s while maintaining stable temperature and vacuum conditions. The LiLiT setup is presently in online commissioning stage for high-intensity proton beam irradiation (1.91–2.5 MeV, 1–2 mA) at SARAF.

  19. An Improved Cryogen for Plunge Freezing

    PubMed Central

    Tivol, William F.; Briegel, Ariane; Jensen, Grant J.

    2011-01-01

    The use of an alkane mixture that remains liquid at 77 K to freeze specimens has advantages over the use of a pure alkane that is solid at 77 K. It was found that a mixture of methane and ethane did not give a cooling rate adequate to produce vitreous ice, but a mixture of propane and ethane did result in vitreous ice. Furthermore, the latter mixture produced less damage to specimens mounted on a very thin, fragile holey carbon substrate. PMID:18793481

  20. A ballistic compressor-based experiment for the visualization of liquid propellant jet combustion above 100 MPa

    NASA Astrophysics Data System (ADS)

    Birk, A.; Kooker, D. E.

    This paper describes the components and operation of an experimental setup for the visualization of liquid propellant (LP) jet combustion at pressures above 100 MPa. The apparatus consists of an in-line ballistic compressor and LP injector. The ballistic compressor, based on a modified 76 mm gun, provides high-pressure (ca. 55 MPa) clear hot gas for the jet ignition. A piston (projectile) is fired toward a test chamber beyond the barrel's end, and its rebound is arrested in a transition section that seals the test chamber to the barrel. The LP jet is injected once the piston is restrained, and combustion of the jet further elevates the pressure. At a preset pressure, a disc in the piston ruptures and the combustion gas vents sonically into the barrel. If a monopropellant is used, the jet injection-combustion process then resembles liquid rocket combustion but at very high pressures (ca. 140 MPa). This paper discusses the ballistics of the compression and compares experimental results to those predicted by a numerical model of the apparatus. Experimentally, a pressure of 70 MPa was achieved upon a 12.5 volumetric compression factor by firing a 10 kg piston into 1.04 MPa argon using a charge of 75 g of small-grain M1 propellant.

  1. Non-thermal processes on ice and liquid micro-jet surfaces

    NASA Astrophysics Data System (ADS)

    Olanrewaju, Babajide O.

    The primary focus of this research is to investigate non-thermal processes occurring on ice surfaces and the photo-ejection of ions from liquid surfaces. Processes at the air-water/ice interface are known to play a very important role in the release of reactive halogen species with atmospheric aerosols serving as catalysts. The ability to make different types of ice with various morphologies, hence, different adsorption and surface properties in vacuum, provide a useful way to probe the catalytic effect of ice in atmospheric reactions. Also, the use of the liquid jet technique provides the rare opportunity to probe liquid samples at the interface; hitherto impossible to investigate with traditional surface science techniques. In Chapter 2, the effect of ice morphology on the release of reactive halogen species from photodissociation of adsorbed organic halides on ice will be presented. Quantum state resolved measurements of neutral atomic iodine from the photon irradiation of submonolayer coverages of methyl iodide adsorbed on low temperature water ice were conducted. Temperature programmed desorption (TPD) studies of methyl iodide adsorbed on ice were performed to provide information on the effect of ice morphology on the adsorption of submonolayer methyl iodide. The interaction and autoionization of HCl on low-temperature (80{140 K) water ice surfaces has been studied using low-energy (5-250 eV) electron-stimulated desorption (ESD) and temperature programmed desorption (TPD). A detailed ESD study of the interactions of low concentrations of HCl with low-temperature porous amorphous solid water (PASW), amorphous solid water (ASW) and crystalline ice (CI) surfaces will be presented in Chapter 3. The ESD cation yields from HCl adsorbed on ice, as well as the coverage dependence, kinetic energy distributions and TPD measurements were all monitored. Probing liquid surface using traditional surface science technique is usually difficult because of the problem of keeping the liquid surface clean and the distortion of information by the interference of equilibrium dense vapor above the liquid. By using the liquid jet technique the ejection of ions from surface of micron sized liquid can be adequately probed with a linear time-of-flight mass spectrometer. The photoionization of pure water and aqueous solutions of NaOH, NaCl and HCl is presented in Chapter 4. The aim of this investigation was to provide a fundamental understanding of the structure of water/vacuum interfaces. In Chapter 5, the ejection of ions from salt solutions containing divalent cations is also presented. The goal of the experiment was to figure out the solvation structure and reaction dynamics of divalent metal ions, M2+ on the surface of aqueous solution. A lot of work has been done in the gas phase either by a pickup-type cluster source or by collision induced dissociation of ejected ions from electrospray. For the first time the direct monitoring of ions ejected from liquid into gas phase is explored. Possible ejection mechanisms for the ejection of cations are discussed extensively in both Chapters 4 and 5. The results presented in this thesis is a combination of experiments performed at the Georgia Institute of Technology and the Pacific Northwest National Laboratory (PNNL) which includes experiments on ice and micro-jet respectively. The results in Chapters 2 and 3 have been submitted to the Journal of Chemical Physics and the Journal of Physical Chemistry respectively. It is important to note that the data presented in Chapter 3 was originally taken by Dr Janine Herring-Captain as part of her thesis work. It is also presented in this thesis due to effort in analyzing the data and preparation of the submitted manuscript. Chapter 4 and 5 represents papers which will also be submitted for publication in the open scientific literature. All the work leading to the results presented in these two chapters were done during my visit to PNNL and I would like to acknowledge that the instrumentation and data acquisition were done in collaboration with Nikolai Pet

  2. Oral and Plunging Ranulas: What is the Most Effective Treatment?

    PubMed Central

    Patel, Mihir R.; Deal, Allison M.; Shockley, William W.

    2015-01-01

    Objectives/Hypothesis Preferred treatment of oral/plunging ranulas remains controversial. We present our experience with ranulas at the University of North Carolina (UNC) and review the literature. Methods Retrospective review. From 1990 to 2007, 16 oral ranulas and 10 plunging ranulas were treated at UNC. Combining the UNC series with the literature identified 864 cases for review. An online survey was conducted to identify current treatment patterns. Results In the UNC series, procedures for oral ranulas varied from ranula excision (50%), combined ranula and sublingual gland excision (44%), excision of the ranula along with the sublingual gland and submandibular gland (6%). A cervical approach was used in nine plunging ranula cases. One case was treated transorally with sublingual gland removal and evacuation of the ranula. Otherwise, the plunging ranula was removed along with the sublingual gland (20%), submandibular gland (50%), or both (20%). One hundred fifty-one complications were identified from the literature. Recurrence was considered a complication and was most prevalent (63%). Nonrecurrent complications included tongue hypesthesia (26%), bleeding/hematoma (7%), postoperative infection (3%), and Wharton’s duct injury (1%). Sublingual gland excision yielded the fewest complications (3%). Procedures and associated complication rates were: transoral excision of sublingual gland (3%); transoral excision of sublingual gland and ranula (12%); marsupialization (24%); transcervical excision of sublingual gland, submandibular gland, and ranula (33%); OK-432 (49%); and aspiration (82%). Conclusions Based on our review, definitive treatment yielding lowest recurrence and complication rates for all ranulas is transoral excision of the ipsilateral sublingual gland with ranula evacuation. PMID:19504549

  3. Wave-turbulence interaction of a low-speed plane liquid wall-jet investigated by particle image velocimetry

    Microsoft Academic Search

    F.-C. Li; Y. Kawaguchi; T. Segawa; K. Suga

    2005-01-01

    The surface-wave amplitude (free-surface level) and the turbulent velocity field of the liquid phase of a plane wall-jet flow have been simultaneously measured by means of particle image velocimetry, which allows for the investigation of surface waves and wave-turbulence interaction. The Reynolds number, Weber number, and Ohnesorge number of the tested flow, based on the bulk velocity, height of the

  4. When Viscous Jets Collide; Liquid Chains, Threads, Webs, Fishbones and Balloons

    E-print Network

    Keshavarz, Bavand

    2013-01-01

    In this fluid dynamics video prepared for the APS-DFD Gallery of Fluid Motion we study the collision of two identical viscous jets at different jet speeds and collision eccentricities. The dynamics of the jet motion are slowed down by orders of magnitude using a synchronized strobe effect coupled with precise timing control of the perturbation frequency imposed on one of the jets. Our results show that different shapes and morphologies appear as we change the collision eccentricity. At low jet speeds ($We_j = 45$) viscous threads and filaments are formed as the jets begin to impinge on each other. As the propagation axis of one of the jets (jet A) is moved closer to the center of the other stream (jet B) they exert a torque on each other. Because of the resulting swirl, jet A rotates around the axis of jet B and finally breaks into droplets through the action of capillary forces; the pinch off of droplets is similar to a stream of balloons which are released in the air. At zero eccentricity the two jets unite...

  5. Liquid jet breakup characterization with application to melt-water mixing

    SciTech Connect

    Ginsberg, T.

    1986-01-01

    Severe accidents in light-water reactors could lead to the flow of molten core material from the initial core region of the reactor vessel to the lower plenum. Steam explosions have been predicted to occur as a result of the contact of the melt with water available in the plenum. It is presently judged by many workers, that the magnitude of the energy released during such an in-vessel explosion would be insufficient to lead to failure of the containment building (SERG, 1985). A major contributing factor in this judgment is that the mass of melt which would participate in the interaction would be limited by the quantity of melt delivered to the lower plenum to the time of the explosion and by the limited breakup of the molten pour stream as it flows through the plenum prior to the explosion. Limited pour stream breakup would lead to limited melt-water mixing and, in addition, to the existence of ''large-scale'' melt masses which may lead to very inefficient thermal-to-mechanical energy conversion. The objective of this paper is to assess the available literature relevant to liquid jet breakup and to assess its implications with respect to the behavior of molten corium pour streams as they would flow from the core region through the lower plenum. Uncertainties in application of the available literature are discussed. 7 refs., 2 figs.

  6. Computer simulation of mobilization and mixing of kaolin with submerged liquid jets in 25,000-gallon horizontal cylindrical tanks

    SciTech Connect

    Eyler, L.L.; Mahoney, L.A.

    1995-03-01

    This report presents and analyzes results of computer model simulation of mobilization and mixing of kaolin using the TEMPEST code. The simulations are conducted in a horizontal cylindrical geometry replicating a 95 m{sup 3} (25,000 gal) test tank at ORNL, which is scaled to approximate Melton Valley Storage tanks, which are 190 m{sup 3} (50,000 gal). Mobilization and mixing is accomplished by two submerged liquid jets. Two configurations are simulated, one with the jets located at the center of the tank lengthwise and one with the jets located 1/4 tank length from one end. Computer simulations of both jet and suction configurations are performed. Total flow rates of 50, 100, and 200 gpm are modeled, corresponding to jet velocities of 1.52, 3.05, 6.10 m/s (5, 10, 20 ft/s). Calculations were performed to a time of 2 h for the center jet location and to a little over 1 h for the quarter jet location. This report presents computer and fluid properties model basis, preliminary numerical testing, and results. The results are presented in form of flow field and sludge layer contours. Degree of mobilization is presented as fraction of initial sludge layer remaining as a function of time. For the center jet location at 200 gpm, the sludge layer is completely mobilized in just over 1 h. For 100 gpm flow, about 5% of the sludge layer remains after 2 h. For 50 gpm flow, nearly 40% of the initial sludge layer remains after 2 h. For the quarter jets at 200 gpm, about 10% of the initial sludge layer remains after 1 h. For 100 gpm, about 40% of the sludge layer remains after 1 h. The boundary of the sludge layer is defined as 98% max packing for the particles. Mixing time estimates for these cases range from between 9.4 h and 16.2 h. A more critical evaluation and comparison of predictions and the test results is needed.

  7. Fluid dynamics and convective heat transfer in impinging jets through implementation of a high resolution liquid crystal technique

    NASA Technical Reports Server (NTRS)

    Kim, K.; Wiedner, B.; Camci, C.

    1993-01-01

    A combined convective heat transfer and fluid dynamics investigation in a turbulent round jet impinging on a flat surface is presented. The experimental study uses a high resolution liquid crystal technique for the determination of the convective heat transfer coefficients on the impingement plate. The heat transfer experiments are performed using a transient heat transfer method. The mean flow and the character of turbulent flow in the free jet is presented through five hole probe and hot wire measurements, respectively. The flow field character of the region near the impingement plate plays an important role in the amount of convective heat transfer. Detailed surveys obtained from five hole probe and hot wire measurements are provided. An extensive validation of the liquid crystal based heat transfer method against a conventional technique is also presented. After a complete documentation of the mean and turbulent flow field, the convective heat transfer coefficient distributions on the impingement plate are presented. The near wall of the impingement plate and the free jet region is treated separately. The current heat transfer distributions are compared to other studies available from the literature. The present paper contains complete sets of information on the three dimensional mean flow, turbulent velocity fluctuations, and convective heat transfer to the plate. The experiments also prove that the present nonintrusive heat transfer method is highly effective in obtaining high resolution heat transfer maps with a heat transfer coefficient uncertainty of 5.7 percent.

  8. Conical tips inside cone-jet electrosprays

    Microsoft Academic Search

    A´lvaro G. Mari´n; Ignacio G. Loscertales; A. Barrero

    2008-01-01

    In coaxial jet electrosprays inside liquid baths, a conductive liquid forms a cone-jet electrospray within a bath containing a dielectric liquid. An additional dielectric liquid is injected inside the Taylor cone, forming a liquid meniscus. The motion of the conductive liquid that flows toward the vertex cone deforms the inner dielectric meniscus until a liquid jet is issued from its

  9. Pneumatic dispensing of nano- to picoliter droplets of liquid metal with the StarJet method for rapid prototyping of metal microstructures

    Microsoft Academic Search

    A. Tropmann; N. Lass; N. Paust; T. Metz; C. Ziegler; R. Zengerle; P. Koltay

    This study presents a new, simple and robust, pneumatically actuated method for the generation of liquid metal micro droplets\\u000a in the nano- to picoliter range. The so-called StarJet dispenser utilizes a star-shaped nozzle geometry that stabilizes liquid\\u000a plugs in its center by means of capillary forces. Single droplets of the liquid metal can be pneumatically generated by the\\u000a interaction of

  10. Experimental investigation of 2D flexible plunging hydrofoil

    NASA Astrophysics Data System (ADS)

    Tian, Ruijun; Mitchell, Robert; Shu, Fangjun

    2012-11-01

    It is believed that both birds and insects benefit from their wing flexibility during the flapping flight. One of the possible benefits is higher lift force generation capability than that of rigid wing models. Both experimental and computational work has discovered that the leading edge vortex (LEV) plays an important role in this advantage of high lift force generating efficiency. In the present work, flow physics related to high lift-generating flexible wings are investigated experimentally. Both flexible and rigid hydrofoils (NACA0012) were actively plunged in glycerol-water solution with various amplitude, frequency and Reynolds number combinations. Phase-locked Particle Image Velocimetry (PIV) measurements were conducted to investigate the generation and evolution of the LEVs. Lift and drag forces during plunging were also measured to uncover the relationship between the force response and the surrounding flow field development. The overall results were also compared between flexible and rigid hydrofoils to provide qualitative data for validation of computational work. Supported by Army High Performance Computing Center.

  11. Flow and forces of flexible wings under a plunging motion

    NASA Astrophysics Data System (ADS)

    Campos, Diego; Ukeiley, Lawrence

    2011-11-01

    The effects of flexibility on the flow fields and production of aerodynamic forces of Zimmerman planform wings with different stiffness are investigated. The wings are subjected to a symmetric sinusoidal plunging motion under forward flight conditions. Particle Image Velocimetry (PIV) is used to measure the flow at different spanwise locations and Laser Doppler Vibrometry (LDV) is utilized to obtain deformation characteristics from the wings. The results from the PIV and LDV analysis are phase averaged discrete points throughout the plunging cycle, resulting in three component flow field data coupled with wing twist obtained from the LDV, thus allowing for a better understanding of the fluid-structure interactions. The forces are then calculated through a momentum balance technique to better understand the effects of different stiffness. The Q criterion is used to identify and analyze the vortical structures that form around the wing. Results show the strongest leading edge vortex formation between 70 and 80 percent span. The effect of the deformation on the production and evolution of the vortical structures will be related to the generation of aerodynamic forces.

  12. Visco Jet Joule-Thomson Device Characterization Tests in Liquid Methane

    NASA Technical Reports Server (NTRS)

    Jurns, John M.

    2009-01-01

    Joule-Thomson (J-T) devices have been identified as critical components for Thermodynamic Vent Systems (TVS) planned for future space exploration missions. Lee Visco Jets (The Lee Company) (Ref. 4) are one type of J-T device that may be used for LCH4 propellant systems. Visco Jets have been previously tested and characterized in LN2 and LH2 (Refs. 6 and 7), but have not been characterized in LOX or LCH4. Previous Visco Jet tests with LH2 resulted in clogging of the Visco Jet orifice under certain conditions. It has been postulated that this clogging was due to the presence of neon impurities in the LH2 that solidified in the orifices. Visco Jets therefore require testing in LCH4 to verify that they will not clog under normal operating conditions. This report describes a series of tests that were performed at the NASA Glenn Research Center to determine if Visco Jets would clog under normal operating conditions with LCH4 propellant. Test results from this program indicate that no decrease in flow rate was observed for the Visco Jets tested, and that current equation used for predicting flow rate appears to under-predict actual flow at high Lohm ratings.

  13. Drop-size distribution for crosscurrent breakup of a liquid jet in a convective airstream

    E-print Network

    Lyn, Gregory Michael

    1994-01-01

    Experimental investigations have been completed in the study of a simulated fuel injector system implementing an airblast atomization process called a jet in a crossflow as the primary means of fuel atomization. To complete these studies...

  14. Generation of capillary instabilities by external disturbances in a liquid jet. Ph.D. Thesis - State Univ. of N.Y.

    NASA Technical Reports Server (NTRS)

    Leib, S. J.

    1985-01-01

    The receptivity problem in a circular liquid jet is considered. A time harmonic axial pressure gradient is imposed on the steady, parallel flow of a jet of liquid emerging from a circular duct. Using a technique developed in plasma physics a casual solution to the forced problem is obtained over certain ranges of Weber number for a number of mean velocity profiles. This solution contains a term which grows exponentially in the downstream direction and can be identified with a capillary instability wave. Hence, it is found that the externally imposed disturbances can indeed trigger instability waves in a liquid jet. The amplitude of the instability wave generated relative to the amplitude of the forcing is computed numerically for a number of cases.

  15. An electron jet pump: The Venturi effect of a Fermi liquid

    Microsoft Academic Search

    D. Taubert; G. J. Schinner; C. Tomaras; H. P. Tranitz; W. Wegscheider; S. Ludwig

    2010-01-01

    A three-terminal device based on a two-dimensional electron system is\\u000ainvestigated in the regime of non-equilibrium transport. Excited electrons\\u000ascatter with the cold Fermi sea and transfer energy and momentum to other\\u000aelectrons. A geometry analogous to a water jet pump is used to create a jet\\u000apump for electrons. Because of its phenomenological similarity we name the\\u000aobserved behavior

  16. Deposit formation in liquid fuels. I - Effect of coal-derived Lewis bases on storage stability of Jet A turbine fuel

    NASA Technical Reports Server (NTRS)

    Dahlin, K. E.; Daniel, S. R.; Worstell, J. H.

    1981-01-01

    The development of reasonably precise techniques for the measurement of storage stability of jet aviation fuel is described. Lewis bases, extracted by ligand-exchange from a coal-derived liquid, are shown to adversely affect storage stability (as determined by an accelerated storage test) when added to Jet A turbine fuel. JFTOT results suggesting slight decreases in thermal stability of fuel 'spiked' (i.e., contaminated with a measured quantity of reagent) with extract are reported. Addition to Jet A turbine fuel of individual heterocyclic nitrogen compounds is shown to produce comparable decreases in storage stability.

  17. The effect of turbulence on the stability of liquid jets and the resulting droplet size distributions. Third quarterly technical report, July 1, 1993--September 30, 1993

    SciTech Connect

    Mansour, A.; Chigier, N.

    1993-12-01

    Laminar and turbulent columns of liquids issuing from capillary tubes were studied in order to determine the effects of turbulence on the stability of liquid jets and to establish the influence of liquid turbulence on droplet size distributions after breakup. Two capillary tubes were chosen with diameters D{sub 1}=3.0mm and D{sub 2}=1.2mm; jet Reynolds numbers were 1000--30000, and 400--7200. For water injection into stagnant air, stability curve is bounded by a laminar portion, where a jet radius and {delta}{sub o} initial disturbance amplitude, and a fully developed turbulent portion characterized by high initial disturbance amplitude (ln(a/{delta}{sub o,T}) {approximately} 4.85). In the transition region, ln(a/{delta}{sub o}) is not single valued; it decreases with increasing Reynolds number. In absence of aerodynamic effects, turbulent jets are as stable as laminar jets. For this breakup mode turbulence propagates initial disturbances with amplitudes orders of magnitude larger than laminar jets ({delta}{sub o,T}=28{times}10{sup 6} {delta}{sub o,L}). Growth rates of initial disturbances are same for both laminar and turbulent columns with theoretical Weber values. Droplet size distribution is bi-modal; the number ratio of large (> D/2), to small (< D/2) droplets is 3 and independent of Reynolds number. For laminar flow optimum wavelength ({lambda}{sub opt}) corresponding to fastest growing disturbance is equal to 4.45D, exactly the theoretical Weber value. For turbulent flow conditions, the turbulent column segments. Typically, segments with lengths of one to several wavelengths, detach from the liquid jet. The long ligaments contract under the action of surface tension, resulting in droplet sizes larger than predicted by Rayleigh and Weber. For turbulent flow conditions, {lambda}{sub opt} = 9.2D, about 2 times the optimum Weber wavelength.

  18. Analysis of a free surface film from a controlled liquid impinging jet over a rotating disk including conjugate effects, with and without evaporation

    Microsoft Academic Search

    Jeremy Rice; Amir Faghri; Baki Cetegen

    2005-01-01

    A detailed analysis of the liquid film characteristics and the accompanying heat transfer of a free surface controlled liquid impinging jet onto a rotating disk are presented. The computations were run on a two-dimensional axi-symmetric Eulerian mesh while the free surface was calculated with the volume of fluid method. Flow rates between 3 and 15lpm with rotational speeds between 50

  19. Liquid Fuel Emulsion Jet-in-Crossflow Penetration and Dispersion Under High Pressure Conditions

    NASA Astrophysics Data System (ADS)

    Gomez, Guillermo Andres

    The current work focuses on the jet-in-crossflow penetration and dispersion behavior of water-in-oil emulsions in a high pressure environment. Both fuel injection strategies of using a water-in-oil emulsion and a jet-in-crossflow have demonstrated unique benefits in improving gas turbine performance from an emissions and efficiency standpoint. A jet-in-crossflow is very practical for use in gas turbine engines, rocket propulsion, and aircraft engines since it utilizes already available crossflow air to atomize fuel. Injecting water into a combustion chamber in the form of a water-in-oil emulsion allows for pollutant emissions reduction while reducing efficiency loses that may result from using a separate water or steam injection circuit. Dispersion effects on oil droplets are expected, therefore investigating the distribution of both oil and water droplets in the crossflow is an objective in this work. Understanding the synchronization and injection behavior of the two strategies is of key interest due to their combined benefits. A water-to-oil ratio and an ambient pressure parameter are developed for emulsion jet-in-crossflow trajectories. To this end, a total of 24 emulsion jet-in-crossflow tests were performed with varying ambient pressures of 2-8 atm and momentum flux ratios of 50, 85, and 120. Sobel edge filtering was applied to each averaged image obtained from a high speed video of each test case. Averaged and filtered images were used to resolve top and bottom edges of the trajectory in addition to the overall peak intensity up to 40 mm downstream of the injection point. An optimized correlation was established and found to differ from literature based correlations obtained under atmospheric pressure conditions. Overall it was found that additional parameters were not necessary for the top edge and peak intensity correlations, but a need for a unique emulsion bottom edge and width trajectory correlation was recognized. In addition to investigating emulsion jet-in-crossflow trajectory correlations, a unique Dual Planar Laser Induced Fluorescence (Dual-PLIF) method was applied for the first time on emulsions at elevated pressure conditions. From the Dual-PLIF results, qualitative observations provided insight into the unique dispersion of oil and water concentrations within a cross-sectional plane down stream of the jet-in-crossflow injection.

  20. Mixing and chemical reaction at high Schmidt number near turbulent/nonturbulent interface in planar liquid jet

    NASA Astrophysics Data System (ADS)

    Watanabe, T.; Naito, T.; Sakai, Y.; Nagata, K.; Ito, Y.

    2015-03-01

    This study investigates the mixing of reactive species at a high Schmidt number (Sc ? 600) near the turbulent/nonturbulent (T/NT) interface in a planar liquid jet with a chemical reaction A + B ? R. Reactants A and B are supplied from the jet and ambient flows, respectively. An I-type hot-film probe and optical fiber probe are used for the simultaneous measurements of the streamwise velocity, mixture fraction, and concentrations of all reactive species and for detecting the T/NT interface. Statistics conditioned on the time elapsed after interface detection are analyzed. The conditional mean mixture fraction and concentrations change sharply near the interface. The widths of these changes are independent of the chemical species. The conditional statistics reveal the dependence of the chemical reaction on the interface orientation. The segregation intensity near the interface shows that the mixing state of the two reactants also depends on the interface orientation. However, the large reaction rate near the interface is related to the large concentration of reactant A rather than the mixing state, because reactant A supplied from the jet tends to be deficient near the interface. Near the interface where the reaction rate is large, the concentration of the chemical product is also large. The difference in the product concentration between the different interface orientations is larger for the infinitely fast reaction (as investigated by using the equilibrium limit) than the finite Damköhler number case, and the dependence of the chemical reaction on the interface orientation is expected to be significant for a fast chemical reaction.

  1. Experimental investigation of liquid jet outflow into a plane ventilated channel in self-oscillatory regimes

    Microsoft Academic Search

    I. I. Kozlov; S. A. Ocheretyanyi; V. V. Prokof’ev

    2011-01-01

    The results of an experimental investigation of self-oscillatory jet outflow into a plane channel with air injection in its\\u000a dead-ended part are presented. It is found that at fixed channel geometry and water supply system the main flow parameters\\u000a depend on the air injection rate and the relative cavity volume. It is shown that with increase in the gas injection

  2. Liquid mixing enhanced by pulse width modulation in a Y-shaped jet configuration

    NASA Astrophysics Data System (ADS)

    Xia, Qingfeng; Zhong, Shan

    2013-04-01

    In this paper, mixing between two fluid streams, which are injected into a planar mixing channel via a Y-shaped confluence section at the same volume flow rate, is studied experimentally. The injection of the two fluid streams is controlled by two separate solenoid valves, which are operated with a phase difference of 180°, using pulse width modulation. The experiments are conducted using water at a mean Reynolds number between 83 and 250, a range of pulsation frequencies and two duty cycles (25 and 50%). Both particle-image velocimetry and planar laser-induced fluorescence technique are used to visualize the flow patterns and to quantify the mixing degree in the mixing channel. This experiment shows that the pulsation of each jet produces vortical structures, which promotes mixing via vortex entrainment and vortex breakup, and at the same time the mixing is also greatly enhanced by sequential segmentation produced by a 180° out-of-phase pulsation of the two jets. This mixing enhancement method is effective at a Reynolds number greater than 125 with a mixing degree of 0.9 being achieved. For the Reynolds numbers studied in the present experiments, an optimal frequency exists, which corresponds to a Strouhal number in the range of 0.5-2. Furthermore, at a given mean Reynolds number a lower duty cycle is found to produce a better mixing due to the resultant higher instantaneous Reynolds number in the jet flow. It is also found that pulsation of only one jet can produce a similar mixing effect.

  3. Three-dimensional Large Eddy Simulation of air entrainment under plunging breaking waves

    Microsoft Academic Search

    Pierre Lubin; Stéphane Vincent; Stéphane Abadie; Jean-Paul Caltagirone

    2006-01-01

    The scope of this work is to present and discuss the results obtained from simulating three-dimensional plunging breaking waves by solving the Navier-Stokes equations, in air and water, coupled with a dynamic subgrid scale turbulence model (Large Eddy Simulation, LES). An original numerical tool is used for the complete description of the plunging breaking processes including overturning, splash-up and the

  4. Postmortem investigation of mylohyoid hiatus and hernia: aetiological factors of plunging ranula.

    PubMed

    Harrison, John D; Kim, Ann; Al-Ali, Saad; Morton, Randall P

    2013-09-01

    The mylohyoid hiatus and hernia were discovered in the nineteenth century and were considered to explain the origin of the plunging ranula from the sublingual gland. This formed the rationale for sublingual sialadenectomy for the treatment of plunging ranula. However, a more recent, extensive histological investigation reported that hernias contained submandibular gland, which supported an origin of the plunging ranula from the submandibular gland and submandibular sialadenectomy for the treatment of plunging ranula. We therefore decided to investigate the occurrence and location of the hiatus and the histological nature of the hernia. Twenty-three adult cadavers were dissected in the submandibular region. The locations and dimensions of mylohyoid hiatuses were measured before taking biopsies of hernias. Hiatuses with associated hernias were found in ten cadavers: unilateral in six; and bilateral in four, in one of which there were three hiatuses. Sublingual gland was identified in nine hernias and fat without gland in six. This investigation supports clinical and experimental evidence that the plunging ranula originates from the sublingual gland and may enter the neck through the mylohyoid muscle. It confirms the rationale of sublingual sialadenectomy for the treatment of plunging ranula. PMID:23355334

  5. Liquid and gelled sprays for mixing hypergolic propellants using an impinging jet injection system

    Microsoft Academic Search

    Mark D. James

    2010-01-01

    The characteristics of sprays produced by liquid rocket injectors are important in understanding rocket engine ignition and performance. The includes, but is not limited to, drop size distribution, spray density, drop velocity, oscillations in the spray, uniformity of mixing between propellants, and the spatial distribution of drops. Hypergolic ignition and the associated ignition delay times are also important features in

  6. Fluctuation-induced dynamics of multiphase liquid jets with ultra-low interfacial tension

    E-print Network

    Paris-Sud XI, Université de

    : 10.1039/c2lc40524e Control of fluid dynamics at the micrometer scale is essential to emulsion science applications. Most studies on multiphase flow focus on oil-water systems with substantial interfacial tension typically involve a combination of oil-based and water-based liquids. It has led to a good description

  7. Flashing liquid jets and two-phase droplet dispersion I. Experiments for derivation of droplet atomisation correlations.

    PubMed

    Cleary, Vincent; Bowen, Phil; Witlox, Henk

    2007-04-11

    The large-scale release of a liquid contained at upstream conditions above its local atmospheric boiling point is a scenario often given consideration in process industry risk analysis. Current-hazard quantification software often employs simplistic equilibrium two-phase approaches. Scaled water experiments have been carried out measuring droplet velocity and droplet size distributions for a range of exit orifice aspect ratios (L/d) and conditions representing low to high superheat. 2D Phase-Doppler Anemometry has been utilised to characterise droplet kinematics and spray quality. Droplet size correlations have been developed for non-flashing, the transition between non-flashing and flashing, and fully flashing jets. Using high-speed shadowography, transition between regimes is defined in terms of criteria identified in the external flow structure. An overview companion paper provides a wider overview of the problem and reports implementation of these correlations into consequence models and subsequent validation. The fluid utilised throughout is water, hence droplet correlations are developed in non-dimensional form to allow extrapolation to other fluids through similarity scaling, although verification of model performance for other fluids is required in future studies. Data is reduced via non-dimensionalisation in terms of the Weber number and Jakob number, essentially representing the fluid mechanics and thermodynamics of the system, respectively. A droplet-size distribution correlation has also been developed, conveniently presented as a volume undersize distribution based on the Rosin-Rammler distribution. Separate correlations are provided for sub-cooled mechanical break-up and fully flashing jets. This form of correlation facilitates rapid estimates of likely mass rainout quantities, as well as full distribution information for more rigorous two-phase thermodynamic modelling in the future. PMID:16956721

  8. Plain-jet airblast atomization of alternative liquid petroleum fuels under high ambient air pressure conditions

    NASA Astrophysics Data System (ADS)

    Jasuja, A. K.

    1982-04-01

    The effects that air and fuel properties have upon the spray mean drop size characteristics of a plain-jet airblast atomizer of the type employed in the gas turbine engine are investigated. The tests used kerosene, gas oil and a high-viscosity blend of gas oil in residual fuel oil, and covered a wide range of ambient air pressures. Laser light-scattering technique was employed for drop size measurements. It is concluded that the atomizer's measured mean drop size characteristics are only slightly different from those of the pre-filming type, especially when operating on low-viscosity kerosene under higher ambient air pressure. The beneficial effect of increased levels of ambient air pressure on mean drop size is shown to be much reduced in the case of high-viscosity fuels, thus making the attainment of good atomization performance on such fuels difficult. An expression is derived for correlating the obtained mean drop size data.

  9. Microbial Inactivation in the Liquid Phase Induced by Multigas Plasma Jet

    PubMed Central

    Takamatsu, Toshihiro; Uehara, Kodai; Sasaki, Yota; Hidekazu, Miyahara; Matsumura, Yuriko; Iwasawa, Atsuo; Ito, Norihiko; Kohno, Masahiro; Azuma, Takeshi; Okino, Akitoshi

    2015-01-01

    Various gas atmospheric nonthermal plasmas were generated using a multigas plasma jet to treat microbial suspensions. Results indicated that carbon dioxide and nitrogen plasma had high sterilization effects. Carbon dioxide plasma, which generated the greatest amount of singlet oxygen than other gas plasmas, killed general bacteria and some fungi. On the other hand, nitrogen plasma, which generated the largest amount of OH radical, killed ?6 log of 11 species of microorganisms, including general bacteria, fungi, acid-fast bacteria, spores, and viruses in 1–15 min. To identify reactive species responsible for bacterial inactivation, antioxidants were added to bacterial suspensions, which revealed that singlet oxygen and OH radicals had greatest inactivation effects. PMID:26173107

  10. Microbial Inactivation in the Liquid Phase Induced by Multigas Plasma Jet.

    PubMed

    Takamatsu, Toshihiro; Uehara, Kodai; Sasaki, Yota; Hidekazu, Miyahara; Matsumura, Yuriko; Iwasawa, Atsuo; Ito, Norihiko; Kohno, Masahiro; Azuma, Takeshi; Okino, Akitoshi

    2015-01-01

    Various gas atmospheric nonthermal plasmas were generated using a multigas plasma jet to treat microbial suspensions. Results indicated that carbon dioxide and nitrogen plasma had high sterilization effects. Carbon dioxide plasma, which generated the greatest amount of singlet oxygen than other gas plasmas, killed general bacteria and some fungi. On the other hand, nitrogen plasma, which generated the largest amount of OH radical, killed ?6 log of 11 species of microorganisms, including general bacteria, fungi, acid-fast bacteria, spores, and viruses in 1-15 min. To identify reactive species responsible for bacterial inactivation, antioxidants were added to bacterial suspensions, which revealed that singlet oxygen and OH radicals had greatest inactivation effects. PMID:26173107

  11. Modeling and simulation of fragmentation of suddenly heated liquid metal jets

    Microsoft Academic Search

    A. Hassanein; I. Konkashbaev

    2001-01-01

    Thermoelastic response of liquid metal targets exposed to high-volumetric-energy deposition in times shorter than the target hydrodynamic response time (i.e., sound travel time) is of interest to several research areas, including first walls of fusion reactors (especially inertially confined fusion reactors), targets for high-power accelerators such as the Spallation Neutron Source, muon collider targets, etc. Under conditions that exist in

  12. The Rayleigh-Plateau instability and jet formation during the extrusion of liquid metal from craters in a vacuum arc cathode spot

    NASA Astrophysics Data System (ADS)

    Mesyats, G. A.; Zubarev, N. M.

    2015-01-01

    We consider the displacement of molten metal from a crater being formed on the cathode during the operation of a vacuum arc under the pressure of the cathode plasma and formulate a criterion for the formation of a thin ridge of expelled liquid metal (a sheet-like jet) at the crater edge. When the ridge height is substantially greater than its thickness, conditions arise for the development of the Rayleigh-Plateau capillary instability, which breaks the axial symmetry of the problem. Estimates are presented, which suggest that this instability is responsible for the breakup of the liquid ridge into jets, which play an important role in the self-sustained operation of a discharge.

  13. The Dynamics of Hot Particle Clouds Plunging Into Water

    NASA Astrophysics Data System (ADS)

    Angelini, Sergio

    1995-01-01

    Upon mixing of a hot liquid and a cold liquid, such as for instance molten steel and water, a very energetic interaction called steam explosion may take place. In the preliminary stages of such an event, the breaking-up hot liquid mixes in a coarse manner with the water, and the result of this mixing plays a very important role in the evolution of the explosion. Primarily, the distribution of the three phases present (hot liquid, cold liquid and vapour of the cold liquid) can provide bounding estimates on the potential energetic yield. With this work, we provide a thorough description of this initial mixing by means of experimental and numerical investigations. As a first approach to the problem, the hot liquid is approximated by a cloud of hot particles: this allows us to create experimentally the well-defined conditions necessary to address the fundamental behaviour. A wide variety of mixing patterns are considered to investigate the effect of particle temperature, size, volume fraction and density, level of water subcooling and geometry of the tank in which the interaction takes place. Special measurement techniques have been developed to gather important data from the highly-transient interaction. Numerically, we utilize the PM-ALPHA code to get a deeper understanding of the details of the mixing, after comparison of the prediction with experimental data has given us some initial basis for doing so.

  14. Effect of exhaust gas recirculation on emissions from a flame-tube combustor using Liquid Jet A fuel

    NASA Technical Reports Server (NTRS)

    Marek, C. J.; Tacina, R. R.

    1976-01-01

    The effects of uncooled exhaust gas recirculation as an inert diluent on emissions of oxides of nitrogen (NO + NO2) and on combustion efficiency were investigated. Ratios of recirculated combustion products to inlet airflow were varied from 10 to 80 percent by using an inlet air ejector nozzle. Liquid Jet A fuel was used. The flame-tube combustor was 10.2 cm in diameter. It was operated with and without a flameholder present. The combustor pressure was maintained constant at 0.5 MPa. The equivalence ratio was varied from 0.3 to 1.0. The inlet air temperature was varied from 590 to 800 K, and the reference velocity from 10 to 30 m/sec. Increasing the percent recirculation from 10 to 25 had the following effects: (1) the peak NOx emission was decreased by 37 percent, from 8 to 5 g NO2/kg fuel, at an inlet air temperature of 590 K and a reference velocity of 15 m/sec; (2) the combustion efficiency was increased, particularly at the higher equivalence ratios; and (3) for a high combustion efficiency of greater than 99.5 percent, the range of operation of the combustor was nearly doubled in terms of equivalence ratio. Increasing the recirculation from 25 to 50 percent did not change the emissions significantly.

  15. CFD based investigation on the impact acceleration when a gannet impacts with water during plunge diving.

    PubMed

    Wang, T M; Yang, X B; Liang, J H; Yao, G C; Zhao, W D

    2013-09-01

    Plunge diving is the most commonly used feeding method of a gannet, which can make the gannet transit from air to water rapidly and successfully. A large impact acceleration can be generated due to the air-to-water transition. However, the impact acceleration experienced by the gannet during plunge diving has not been studied. In this paper, this issue is investigated by using the CFD method. The effect of the dropping height and the water-entry inclination angle on the impact acceleration is considered. The results reveal that the impact acceleration along the longitudinal body axis increases with either of the two parameters. The peak time decreases with the dropping height. A quadratic relation is found between the peak impact acceleration and the initial water-entry velocity. According to the computation, when the dropping height is 30 m (most of gannets plunge from about this height), the peak impact acceleration can reach about 23 times the gravitational acceleration, which will exert a considerable force on the gannet body. Furthermore, the pressure distribution of different water-entry inclination angles indicates that the large pressure asymmetry caused by a small oblique angle may lead to a large impact acceleration in the direction perpendicular to the longitudinal body axis and cause damage to the neck of the gannet, which partly explains the reason why a gannet performing a high plunge diving in nature enters water with a large oblique angle from the perspective of impact mechanics. The investigation on the plunge-diving behavior in this paper will inspire and promote the development of a biomimetic amphibious robot that transits from air to water with the plunge-diving mode. PMID:23851321

  16. First application of liquid-metal-jet sources for small-animal imaging: High-resolution CT and phase-contrast tumor demarcation

    SciTech Connect

    Larsson, Daniel H.; Lundstroem, Ulf; Burvall, Anna; Hertz, Hans M. [Department of Applied Physics, KTH Royal Institute of Technology/Albanova, 10691 Stockholm (Sweden); Westermark, Ulrica K.; Arsenian Henriksson, Marie [Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, 17177 Stockholm (Sweden)

    2013-02-15

    Purpose: Small-animal studies require images with high spatial resolution and high contrast due to the small scale of the structures. X-ray imaging systems for small animals are often limited by the microfocus source. Here, the authors investigate the applicability of liquid-metal-jet x-ray sources for such high-resolution small-animal imaging, both in tomography based on absorption and in soft-tissue tumor imaging based on in-line phase contrast. Methods: The experimental arrangement consists of a liquid-metal-jet x-ray source, the small-animal object on a rotating stage, and an imaging detector. The source-to-object and object-to-detector distances are adjusted for the preferred contrast mechanism. Two different liquid-metal-jet sources are used, one circulating a Ga/In/Sn alloy and the other an In/Ga alloy for higher penetration through thick tissue. Both sources are operated at 40-50 W electron-beam power with {approx}7 {mu}m x-ray spots, providing high spatial resolution in absorption imaging and high spatial coherence for the phase-contrast imaging. Results: High-resolution absorption imaging is demonstrated on mice with CT, showing 50 {mu}m bone details in the reconstructed slices. High-resolution phase-contrast soft-tissue imaging shows clear demarcation of mm-sized tumors at much lower dose than is required in absorption. Conclusions: This is the first application of liquid-metal-jet x-ray sources for whole-body small-animal x-ray imaging. In absorption, the method allows high-resolution tomographic skeletal imaging with potential for significantly shorter exposure times due to the power scalability of liquid-metal-jet sources. In phase contrast, the authors use a simple in-line arrangement to show distinct tumor demarcation of few-mm-sized tumors. This is, to their knowledge, the first small-animal tumor visualization with a laboratory phase-contrast system.

  17. Development of liquid-lithium film jet-flow for the target of (7)Li(p,n)(7)Be reactions for BNCT.

    PubMed

    Kobayashi, Tooru; Miura, Kuniaki; Hayashizaki, Noriyosu; Aritomi, Masanori

    2014-06-01

    A feasibility study on liquid lithium target in the form of a flowing film was performed to evaluate its potential use as a neutron generation target of (7)Li(p,n)(7)Be reaction in BNCT. The target is a windowless-type flowing film on a concave wall. Its configuration was adapted for a proton beam which is 30mm in diameter and with energy and current of up to 3MeV and 20mA, respectively. The flowing film of liquid lithium was 0.6mm in thickness, 50mm in width and 50mm in length. The shapes of the nozzle and concave back wall, which create a stable flowing film jet, were decided based on water experiments. A lithium hydrodynamic experiment was performed to observe the stability of liquid lithium flow behavior. The flowing film of liquid lithium was found to be feasible at temperatures below the liquid lithium boiling saturation of 342°C at the surface pressure of 1×10(-3)Pa. Using a proto-type liquid lithium-circulating loop for BNCT, the stability of the film flow was confirmed for velocities up to 30m/s at 220°C and 250°C in vacuum at a pressure lower than 10(-3) Pa. It is expected that for practical use, a flowing liquid lithium target of a windowless type can solve the problem of radiation damage and target cooling. PMID:24412425

  18. Effect of nozzle configuration on transport in the stagnation zone of axisymmetric, impinging free-surface liquid jets: Part 1-turbulent flow structure

    SciTech Connect

    Stevens, J.; Pan, Y.; Webb, B.W. (Brigham Young Univ., Provo, UT (United States))

    1992-11-01

    This study characterized the mean and fluctuating parts of the radial component of the local velocity in the stagnation region of an impinging, free-surface liquid jet striking a smooth flat plate. Four different nozzle exit conditions were studied, including fully developed pipe flow, a contoured nozzle, and turbulence-damped and undamped sharp-edged orifices. Liquid jet Reynolds numbers in the range 30,000 to 55,000 were investigated. Velocities were measured using laser-Doppler velocimetry. Mean velocities were found to vary nearly linearly with radial location, with the slope of the line being a function of distance from the impingement plate. Dimensionless mean velocity gradients, of relevance to the heat transfer, were found to be a strong function of nozzle type, but roughly independent of jet Reynolds number for a given nozzle type. Turbulence levels were also found to be strongly influenced by the nozzle exit-condition. Local heat transfer data corresponding to the flow structure measurements presented here are reported in Part 2 of this study. 22 refs., 9 figs.

  19. Occurrence and origin of submarine plunge pools at the base of the US continental slope

    E-print Network

    Hogg, Andrew

    Occurrence and origin of submarine plunge pools at the base of the US continental slope Simon E to reduced bed shear stress downstream of hydraulic jumps in submarine sediment-laden density flows £ows; continental slope; morphology; hydraulic jump 1. Introduction Submarine sediment-laden density

  20. Turbulence transport, vorticity dynamics, and solute mixing under plunging breaking waves in surf zone

    Microsoft Academic Search

    Pengzhi Lin; Philip L.-F. Liu

    1998-01-01

    Plunging breaking waves generate turbulence and vorticity, which are of great importance for the solute and sediment transport in surf zone. In this paper the complex breaking processes are simulated by using an accurate numerical model that solves the Reynolds equations for the mean flow and modified k-? equations for the turbulence field. A solute transport model is employed to

  1. Effect of nozzle configuration on transport in the stagnation zone of axisymmetric, impinging free-surface liquid jets: Part 2-local heat transfer

    SciTech Connect

    Pan, Y.; Stevens, J.; Webb, B.W. (Brigham Young Univ., Provo, UT (United States))

    1992-11-01

    This is the second of a two-part study on the flow structure and heat transfer characteristics of turbulent, free-surface liquid jets. Part 2 deals with the effect of selected nozzle configurations on the local heat transfer in the stagnation zone. Infrared techniques have been used to characterize the local heat transfer for the four nozzle configurations whose mean and turbulent flow structure was detailed in Part 1. The results show that for identical jet Reynolds numbers, significant differences exist in the magnitudes of the local Nusselt number for the nozzle types studied. Differences of approximately 40 percent were observed. Local heat transfer results reveal that for already turbulent jets, the mean radial velocity gradient appears to be more influential in determining the heat transfer than incremental changes in the level of turbulence (as measured by the radial component of the fluctuations). An empirical correlation of the experimental data supports this conclusion, and reveals that the stagnation Nusselt number is affected independently by the jet Reynolds number and the dimensionless mean radial velocity gradient. 21 refs., 6 figs.

  2. Atomization by jet impact

    Microsoft Academic Search

    N. Bremond; E. Villermaux

    2006-01-01

    The formation and fragmentation of liquid sheets resulting from the oblique collision of two identical cylindrical jets is investigated. The liquid expands radially from the impacting point forming a sheet in the form of a bay leaf bounded by a thicker rim. The sheet shape, rim size and liquid velocity field are quantified and represented analytically. External harmonic perturbations of

  3. Updated Pumpable Liquid Volume Estimates and Jet Pump Durations for Interim Stabilization of Remaining Single Shell Tanks (SST)

    Microsoft Academic Search

    2003-01-01

    The document calculates the pumpable liquid remaining in the 11 unstabilized Consent Decree tanks, as well as updating the estimated pumpable liquid volume in the 29 Consent Decree tanks in June 1, 1998. Data is updated to April 1, 2003.

  4. Fault-related folding during extension: Plunging basement-cored folds in the Basin and Range

    USGS Publications Warehouse

    Howard, K.A.; John, Barbara E.

    1997-01-01

    Folds are able to form in highly extended areas where stratified cover rocks respond to basement fault offsets. The response of cover rocks to basement faulting can be studied especially well in plunging structures that expose large structural relief. The southern Basin and Range province contains plunging folds kilometres in amplitude at the corners of domino-like tilt blocks of basement rocks, where initially steep transverse and normal faults propagated upward toward the layered cover rocks. Exposed tilted cross sections, as much as 8 km thick, display transitions from faulted basement to folded cover that validate laboratory models of forced folds. The folded cover masks a deeper extensional style of brittle segmentation and uniform steep tilting.

  5. Comparison of propagation- and grating-based x-ray phase-contrast imaging techniques with a liquid-metal-jet source

    NASA Astrophysics Data System (ADS)

    Zhou, T.; Lundström, U.; Thüring, Thomas; Rutishauser, S.; Larsson, D. H.; Stampanoni, M.; David, C.; Hertz, H. M.; Burvall, A.

    2014-03-01

    X-ray phase-contrast imaging has been developed as an alternative to conventional absorption imaging, partly for its dose advantage over absorption imaging at high resolution. Grating-based imaging (GBI) and propagation-based imaging (PBI) are two phase-contrast techniques used with polychromatic laboratory sources. We compare the two methods by experiments and simulations with respect to required dose. A simulation method based on the projection approximation is designed and verified with experiments. A comparison based on simulations of the doses required for detection of an object with respect to its diameter is presented, showing that for monochromatic radiation, there is a dose advantage for PBI for small features but an advantage for GBI at larger features. However, GBI suffers more from the introduction of polychromatic radiation, in this case so much that PBI gives lower dose for all investigated feature sizes. Furthermore, we present and compare experimental images of biomedical samples. While those support the dose advantage of PBI, they also highlight the GBI advantage of quantitative reconstruction of multimaterial samples. For all experiments a liquid-metal-jet source was used. Liquid-metal-jet sources are a promising option for laboratory-based phase-contrast imaging due to the relatively high brightness and small spot size.

  6. Thermal Tolerance Limits of Diamondback Moth in Ramping and Plunging Assays

    PubMed Central

    Nguyen, Chi; Bahar, Md Habibullah; Baker, Greg; Andrew, Nigel R.

    2014-01-01

    Thermal sensitivity is a crucial determinant of insect abundance and distribution. The way it is measured can have a critical influence on the conclusions made. Diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae) is an important insect pest of cruciferous crops around the world and the thermal responses of polyphagous species are critical to understand the influences of a rapidly changing climate on their distribution and abundance. Experiments were carried out to the lethal temperature limits (ULT0 and LLT0: temperatures where there is no survival) as well as Upper and Lower Lethal Temperature (ULT25 and LLT25) (temperature where 25% DBM survived) of lab-reared adult DBM population to extreme temperatures attained by either two-way ramping (ramping temperatures from baseline to LT25 and ramping back again) or sudden plunging method. In this study the ULT0 for DBM was recorded as 42.6°C and LLT0 was recorded as ?16.5°C. DBM had an ULT25 of 41.8°C and LLT25 of ?15.2°C. The duration of exposure to extreme temperatures had significant impacts on survival of DBM, with extreme temperatures and/or longer durations contributing to higher lethality. Comparing the two-way ramping temperature treatment to that of direct plunging temperature treatment, our study clearly demonstrated that DBM was more tolerant to temperature in the two-way ramping assay than that of the plunging assay for cold temperatures, but at warmer temperatures survival exhibited no differences between ramping and plunging. These results suggest that DBM will not be put under physiological stress from a rapidly changing climate, rather access to host plants in marginal habitats has enabled them to expand their distribution. Two-way temperature ramping enhances survival of DBM at cold temperatures, and this needs to be examined across a range of taxa and life stages to determine if enhanced survival is widespread incorporating a ramping recovery method. PMID:24475303

  7. Thermal tolerance limits of diamondback moth in ramping and plunging assays.

    PubMed

    Nguyen, Chi; Bahar, Md Habibullah; Baker, Greg; Andrew, Nigel R

    2014-01-01

    Thermal sensitivity is a crucial determinant of insect abundance and distribution. The way it is measured can have a critical influence on the conclusions made. Diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae) is an important insect pest of cruciferous crops around the world and the thermal responses of polyphagous species are critical to understand the influences of a rapidly changing climate on their distribution and abundance. Experiments were carried out to the lethal temperature limits (ULT? and LLT?: temperatures where there is no survival) as well as Upper and Lower Lethal Temperature (ULT?? and LLT??) (temperature where 25% DBM survived) of lab-reared adult DBM population to extreme temperatures attained by either two-way ramping (ramping temperatures from baseline to LT?? and ramping back again) or sudden plunging method. In this study the ULT0 for DBM was recorded as 42.6°C and LLT? was recorded as -16.5°C. DBM had an ULT?? of 41.8°C and LLT25 of -15.2°C. The duration of exposure to extreme temperatures had significant impacts on survival of DBM, with extreme temperatures and/or longer durations contributing to higher lethality. Comparing the two-way ramping temperature treatment to that of direct plunging temperature treatment, our study clearly demonstrated that DBM was more tolerant to temperature in the two-way ramping assay than that of the plunging assay for cold temperatures, but at warmer temperatures survival exhibited no differences between ramping and plunging. These results suggest that DBM will not be put under physiological stress from a rapidly changing climate, rather access to host plants in marginal habitats has enabled them to expand their distribution. Two-way temperature ramping enhances survival of DBM at cold temperatures, and this needs to be examined across a range of taxa and life stages to determine if enhanced survival is widespread incorporating a ramping recovery method. PMID:24475303

  8. Dynamics of surf-zone turbulence in a strong plunging breaker

    Microsoft Academic Search

    Francis C. K. Ting; James T. Kirby

    1995-01-01

    The characteristics of turbulence created by a plunging breaker on a 1 on 35 plane slope have been studied experimentally in a two-dimensional wave tank. The experiments involved detailed measurements of fluid velocities below trough level and water surface elevations in the surf zone using a fibre-optic laser-Doppler anemometer and a capacitance wave gage. The dynamical role of turbulence is

  9. Elemental Water Impact Test: Phase 3 Plunge Depth of a 36-Inch Aluminum Tank Head

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.

    2014-01-01

    Spacecraft are being designed based on LS-DYNA water landing simulations. The Elemental Water Impact Test (EWIT) series was undertaken to assess the accuracy of LS-DYNA water impact simulations. Phase 3 featured a composite tank head that was tested at a range of heights to verify the ability to predict structural failure of composites. To support planning for Phase 3, a test series was conducted with an aluminum tank head dropped from heights of 2, 6, 10, and 12 feet to verify that the test article would not impact the bottom of the test pool. This report focuses on the comparisons of the measured plunge depths to LS-DYNA predictions. The results for the tank head model demonstrated the following. 1. LS-DYNA provides accurate predictions for peak accelerations. 2. LS-DYNA consistently under-predicts plunge depth. An allowance of at least 20% should be added to the LS-DYNA predictions. 3. The LS-DYNA predictions for plunge depth are relatively insensitive to the fluid-structure coupling stiffness.

  10. Pool-Type Fishways: Two Different Morpho-Ecological Cyprinid Species Facing Plunging and Streaming Flows

    PubMed Central

    Branco, Paulo; Santos, José M.; Katopodis, Christos; Pinheiro, António; Ferreira, Maria T.

    2013-01-01

    Fish are particularly sensitive to connectivity loss as their ability to reach spawning grounds is seriously affected. The most common way to circumvent a barrier to longitudinal connectivity, and to mitigate its impacts, is to implement a fish passage device. However, these structures are often non-effective for species with different morphological and ecological characteristics so there is a need to determine optimum dimensioning values and hydraulic parameters. The aim of this work is to study the behaviour and performance of two species with different ecological characteristics (Iberian barbel Luciobarbus bocagei–bottom oriented, and Iberian chub Squalius pyrenaicus–water column) in a full-scale experimental pool-type fishway that offers two different flow regimes–plunging and streaming. Results showed that both species passed through the surface notch more readily during streaming flow than during plunging flow. The surface oriented species used the surface notch more readily in streaming flow, and both species were more successful in moving upstream in streaming flow than in plunging flow. Streaming flow enhances upstream movement of both species, and seems the most suitable for fishways in river systems where a wide range of fish morpho-ecological traits are found. PMID:23741465

  11. Surf-generated noise signatures: a comparison of plunging and spilling breakers.

    PubMed

    Means, Steven L; Heitmeyer, Richard M

    2002-08-01

    Range-time-frequency distributions of surf-generated noise were measured within the surf zone during the SandyDuck'97 experiment at Duck, NC. A 24-phone, 138-m, bottom-mounted, linear array located along a line perpendicular to the shore at a depth of 1 to 3 m recorded the surf-generated noise. Concurrent video measurements of the location, size, and time-evolution of the individual breaking waves directly above the array were made from a nearby 43-m tower. Source level spectra are obtained by using a modified fast field program to account for water column and geoacoustic propagation from the distributed source region to an individual hydrophone. The length, location, and orientation of the leading edge of breakers are tracked in time from rectified video images. It is observed that the source levels from spilling breakers are lower (approximately 5-10 dB) than those produced by plunging breakers that occurred during the same time period. Plunging breakers generated time-frequency signatures with a sharp onset while spilling breakers' signatures had a gradual low-frequency precursor. Range-time signatures of plunging breakers indicate a burst of acoustic energy while spilling breakers' signatures depict sound being generated over a longer time period with the source region moving with the breaking surface wave. PMID:12186029

  12. Effect of a Plunge Electrode During Field Stimulation of Cardiac Tissue

    NASA Astrophysics Data System (ADS)

    Wikswo, J.; Woods, M.; Sidorov, V.; Langrill, D.; Roth, B.

    2003-03-01

    The response of cardiac tissue to strong electric fields is determined by 3-D cable properties, bidomain anisotropy, nonlinearities, and, most importantly, heterogeneities. Langrill and Roth (IEEE Trans. BME. 48:1207 (2001)) numerically studied the effect of a plunge electrode and found alternating regions of hyperpolarization and depolarization around the electrode in response to field shock. We sought to experimentally verify their results by using field stimulation and optical imaging of di-4-ANEPPS stained rabbit right ventricles with an insulated needle serving as a plunge electrode/heterogeneity. The experimental and numerical results agree qualitatively. The key discrepancy is the larger spatial extent of the polarization in the experimental data. The combination of transmural fiber rotation and fluorescence averaging over depth may cause the spatial scale to be larger than was predicted numerically. Because adjacent regions of opposite polarization are potential sources of wave front generation, our results suggest that plunge electrodes or similar-sized heterogeneities may play a role in far-field stimulation.

  13. Numerical heat transfer during partially-confined, confined, and free liquid jet impingement with rotation and chemical mechanical planarization process modeling

    NASA Astrophysics Data System (ADS)

    Lallave Cortes, Jorge C.

    This work presents the use of numerical modeling for the analysis of transient and steady state liquid jet impingement for cooling application of electronics, and energy dissipation during a CMP process under the influence of a series of parameters that controls the transport phenomena mechanism. Seven thorough studies were done to explore how the flow structure and conjugated heat transfer in both the solid and fluid regions was affected by adding a secondary rotational flow during the jet impingement process. Axis-symmetrical numerical models of round jets with a spinning or static nozzle were developed using the following configurations: confined, partially-confined, and free liquid jet impingement on a rotating or stationary uniformly heated disk of finite thickness and radius. Calculations were done for various materials, namely copper, silver, Constantan, and silicon with a solid to fluid thermal conductivity ratio covering a range of 36.91.2222, at different laminar Reynolds numbers ranging from 220 to 2,000, under a broad rotational rate range of 0 to 1,000 RPM (Ekman number=infinity--3.31x10--5), nozzle-to-plate spacing (beta=0.25.5.0), dimensionless disk thicknesses (b/dn=0.167.1.67), confinement ratio (rp/rd=0.2.0.75), and Prandtl number (1.29.124.44) using NH3, H2O, FC.77 and MIL.7808 as working fluids. An engineering correlation relating the average Nusselt number with the above parameters was developed for the prediction of system performance. The simulation results compared reasonably well with previous experimental studies. The second major contribution of this research was the development of a three dimensional CMP model that shows the temperature distributions profile as an index of energy dissipation at the wafer and pad surfaces, and slurry interface. A finite element analysis was done with FIDAP 8.7.4 package under the influence of physical parameters, such as slurry flow rates (0.5.1.42 cc/s), polishing pressures (17.24.41.37 kPa), pad spinning rates (100.250 RPM), carrier spinning rates (15.75 RPM), and slurry film thicknesses (40.200 mum). Results in this study provide further insight of how the above parameters influence the thermal aspects of pad and wafer temperature and heat transfer coefficients distributions across the control volume under study. Numerical results support the interpretation of the experimental data.

  14. Higher-Order Spectral Analysis of a Nonlinear Pitch and Plunge Apparatus

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.; Strganac, Thomas W.; Hajj, Muhammad R.

    2005-01-01

    Simulated aeroelastic responses of a nonlinear pitch and plunge apparatus are analyzed using various statistical signal processing techniques including higher-order spectral methods. A MATLAB version of the Nonlinear Aeroelastic Testbed Apparatus (NATA) at the Texas A&M University is used to generate various aeroelastic response data including limit cycle oscillations (LCO). Traditional and higher-order spectral (HOS) methods are applied to the simulated aeroelastic responses. Higher-order spectral methods are used to identify critical signatures that indicate the transition from linear to nonlinear (LCO) aeroelastic behavior.

  15. Plunge basins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An outlet works is a combination of structures and equipment required for the safe operation and control of water released from a reservoir to serve various purposes like regulating stream flow and water quality; releasing floodwater; and/or providing irrigation, municipal, or industrial water. Out...

  16. Plunge Video

    NSDL National Science Digital Library

    Gene Feldman

    Seven short animations present a tour under the Pacific Ocean based on real data about the sea floor's peaks and valleys. Visitors submerge near Hawaii, continue as if in a submarine to Japan, and finally dive to the ocean's deepest point in the Marianas Trench, between Japan and New Guinea. The tour is based on bathymetric, topographic, and astronomical data provided by the University of Hawaii and various federal agencies.

  17. Effect of flexibility of wing on aerodynamic performance in plunge motion

    NASA Astrophysics Data System (ADS)

    Le, Tuyen Quang; Ko, Jin Hwan; Park, Soo Hyung; Byun, Doyoung

    2009-11-01

    The improvement of aerodynamic performance in plunge motion is investigated through a flexibility of chordwise and spanwise directions by applied a prescribed deformation on a airfoil at Reynolds number of 30000. The aerodynamic performance of flapping motion can be evaluated through a thrust force, a input power and a propulsive efficiency which is a ratio of propulsive power which generate from thrust force to input power. Unsteady viscous flows over NACA 0012 airfoils in plunge motions are computed by using a time-accurate preconditioned Navier-Stokes solver coupled with a volume grid deformation code. For spanwise or chordwise flexibility, there is a optimal phase angle for maximum thrust force and propulsive efficiency. Especially, a combination of spanwise and chordwise flexibility can improve aerodynamic performance higher than that of adding increment from each of flexibility. Compared with rigid motion, 10% deformation in chordwise and spanwise directions with zero phase angle can enhance the thrust force coefficient from 0.22 to 0.38 and 0.54 respectively, while thrust force coefficient is 0.8 by combination of spanwise and chordwise flexibility.

  18. Jet Streams

    NSDL National Science Digital Library

    COMET

    2012-11-13

    This module describes the general characteristics of upper-level jet streams (Polar Jet, Subtropical Jet, and Tropical Easterly Jet) and two major tropical low-level wind maxima (Somali Jet, African Easterly Jet). Included are discussions of their formation, maintenance, influence on synoptic weather, and role in the general circulation.

  19. Viscoelasticity Breaks the Symmetry of Impacting Jets

    NASA Astrophysics Data System (ADS)

    Lhuissier, H.; Néel, B.; Limat, L.

    2014-11-01

    A jet of a Newtonian liquid impacting on a wall at right angle spreads as a thin liquid sheet which preserves the radial symmetry of the jet. We report that for a viscoelastic jet (solution of polyethylene glycol in water) this symmetry can break; close to the wall, the jet cross section becomes faceted and radial steady liquid films (wings) form, which connect the cross-section vertices to the sheet. The number of wings increases with increasing the viscoelastic relaxation time of the solution, but also with increasing jet velocity and decreasing distance from the jet nozzle to the wall. We propose a mechanism for this surprising destabilization of the jet shape, which develops perpendicularly to the direction expected for a buckling mechanism, and explain these dependencies. We also discuss the large-scale consequences of the jet destabilization on the sheet spreading and fragmentation, which show through the faceting of hydraulic jumps and of suspended (Savart) sheets.

  20. Twin Jet

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda; Bozak, Rick

    2010-01-01

    Many subsonic and supersonic vehicles in the current fleet have multiple engines mounted near one another. Some future vehicle concepts may use innovative propulsion systems such as distributed propulsion which will result in multiple jets mounted in close proximity. Engine configurations with multiple jets have the ability to exploit jet-by-jet shielding which may significantly reduce noise. Jet-by-jet shielding is the ability of one jet to shield noise that is emitted by another jet. The sensitivity of jet-by-jet shielding to jet spacing and simulated flight stream Mach number are not well understood. The current experiment investigates the impact of jet spacing, jet operating condition, and flight stream Mach number on the noise radiated from subsonic and supersonic twin jets.

  1. An elastic mounting system for a wing providing continuously non-linear responses in pitch and plunge 

    E-print Network

    Barnett, Walter Joseph

    1996-01-01

    A device was built that provides smooth non-linear restoring forces and moments to the pitch and plunge of a wing in a wind tunnel. The device uses an innovative combination of cams and linear extension springs to produce the restoring forces which...

  2. An elastic mounting system for a wing providing continuously non-linear responses in pitch and plunge

    E-print Network

    Barnett, Walter Joseph

    1996-01-01

    A device was built that provides smooth non-linear restoring forces and moments to the pitch and plunge of a wing in a wind tunnel. The device uses an innovative combination of cams and linear extension springs to produce the restoring forces which...

  3. Visual accommodation and active pursuit of prey underwater in a plunge-diving bird: the Australasian gannet

    PubMed Central

    Machovsky-Capuska, Gabriel E.; Howland, Howard C.; Raubenheimer, David; Vaughn-Hirshorn, Robin; Würsig, Bernd; Hauber, Mark E.; Katzir, Gadi

    2012-01-01

    Australasian gannets (Morus serrator), like many other seabird species, locate pelagic prey from the air and perform rapid plunge dives for their capture. Prey are captured underwater either in the momentum (M) phase of the dive while descending through the water column, or the wing flapping (WF) phase while moving, using the wings for propulsion. Detection of prey from the air is clearly visually guided, but it remains unknown whether plunge diving birds also use vision in the underwater phase of the dive. Here we address the question of whether gannets are capable of visually accommodating in the transition from aerial to aquatic vision, and analyse underwater video footage for evidence that gannets use vision in the aquatic phases of hunting. Photokeratometry and infrared video photorefraction revealed that, immediately upon submergence of the head, gannet eyes accommodate and overcome the loss of greater than 45 D (dioptres) of corneal refractive power which occurs in the transition between air and water. Analyses of underwater video showed the highest prey capture rates during WF phase when gannets actively pursue individual fish, a behaviour that very likely involves visual guidance, following the transition after the plunge dive's M phase. This is to our knowledge the first demonstration of the capacity for visual accommodation underwater in a plunge diving bird while capturing submerged prey detected from the air. PMID:22874749

  4. Characteristic length scales for vortex detachment on plunging profiles with varying leading-edge geometry

    NASA Astrophysics Data System (ADS)

    Rival, David E.; Kriegseis, Jochen; Schaub, Pascal; Widmann, Alexander; Tropea, Cameron

    2014-01-01

    Experiments on leading-edge vortex (LEV) growth and detachment from a plunging profile have been conducted in a free-surface water tunnel. Direct-force and velocity-field measurements have been performed at a Reynolds number of Re = 10,000, a reduced frequency of k = 0.25, and a Strouhal number of St = 0.16, for three varying leading-edge geometries. The leading-edge shape is shown to influence the shear layer feeding the LEV, and thus to some extent the development of the LEV and associated flow topology. This effect in turn influences the arrival time of the rear (LEV) stagnation point at the trailing edge, which, once breached, constitutes a detachment of the LEV. It is found that despite minor phase changes in LEV detachment through leading-edge shape, the position of the trailing edge (chord length) should be chosen as the characteristic length scale for the vortex separation process.

  5. Jet pump assisted artery

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A procedure for priming an arterial heat pump is reported; the procedure also has a means for maintaining the pump in a primed state. This concept utilizes a capillary driven jet pump to create the necessary suction to fill the artery. Basically, the jet pump consists of a venturi or nozzle-diffuser type constriction in the vapor passage. The throat of this venturi is connected to the artery. Thus vapor, gas, liquid, or a combination of the above is pumped continuously out of the artery. As a result, the artery is always filled with liquid and an adequate supply of working fluid is provided to the evaporator of the heat pipe.

  6. Jet Substructure

    NASA Astrophysics Data System (ADS)

    Shelton, J.

    2013-08-01

    Jet physics is a rich and rapidly evolving field, with many applications to physics in and beyond the Standard Model. These notes, based on lectures delivered at the June 2012 Theoretical Advanced Study Institute, provide an introduction to jets at the Large Hadron Collider. Topics covered include sequential jet algorithms, jet shapes, jet grooming, and boosted Higgs and top tagging.

  7. Optimization of anaerobic co-digestion of olive mill wastewater and liquid poultry manure in batch condition and semi-continuous jet-loop reactor.

    PubMed

    Khoufi, Sonia; Louhichi, Assawer; Sayadi, Sami

    2015-04-01

    Anaerobic co-digestion of olive mill wastewater (OMW) with liquid poultry manure (LPM) was investigated in a jet-loop reactor (JLR) as a new approach for upgrading the efficiency of bioprocess. Optimum proportion of LPM was evaluated by determining biochemical methane potential. Methane yields were compared by applying one way ANOVA method followed by post hoc Tukey's test with a 0.05 significance level. Results demonstrated that the addition of LPM at proportion of 10% and 30% (v/v) improved methane yield of OMW digestion but differences between these mixtures and raw OMW are not significant. JLR results confirmed that the proportion 30% LPM gives the optimum condition for excellent stability of digester. Methane production was significantly high until an organic loading rate of 9.5 gCOD/L reactor/day. Overall; this study indicates the technical feasibility and effectiveness of using JLR as one-stage anaerobic system for the co-digestion of OMW and LPM. PMID:25682225

  8. Nozzle and Jet Studies Foluso Ladeinde

    E-print Network

    McDonald, Kirk

    (CLSVOF) -- ANSYS FLUENT · Computational Fluid Dynamics (CFD) code used for simulation, visualization (TI) (a) (b) (a) (b) #12;Jet Flow Using CLSVOF in FLUENT (1) Fig. 11 (a) Development of the liquid jet(,)1( Jet Flow Using CLSVOF in FLUENT (4) B. A. Nichita, 2010, An improved CFD tool to simulate adiabatic

  9. Vortex diode jet

    DOEpatents

    Houck, Edward D. (Idaho Falls, ID)

    1994-01-01

    A fluid transfer system that combines a vortex diode with a jet ejector to transfer liquid from one tank to a second tank by a gas pressurization method having no moving mechanical parts in the fluid system. The vortex diode is a device that has a high resistance to flow in one direction and a low resistance to flow in the other.

  10. Low electrical resistivity associated with plunging of the Nazca flat slab beneath Argentina.

    PubMed

    Booker, John R; Favetto, Alicia; Pomposiello, M Cristina

    2004-05-27

    Beneath much of the Andes, oceanic lithosphere descends eastward into the mantle at an angle of about 30 degrees (ref. 1). A partially molten region is thought to form in a wedge between this descending slab and the overlying continental lithosphere as volatiles given off by the slab lower the melting temperature of mantle material. This wedge is the ultimate source for magma erupted at the active volcanoes that characterize the Andean margin. But between 28 degrees and 33 degrees S the subducted Nazca plate appears to be anomalously buoyant, as it levels out at about 100 km depth and extends nearly horizontally under the continent. Above this 'flat slab', volcanic activity in the main Andean Cordillera terminated about 9 million years ago as the flattening slab presumably squeezed out the mantle wedge. But it is unknown where slab volatiles go once this happens, and why the flat slab finally rolls over to descend steeply into the mantle 600 km further eastward. Here we present results from a magnetotelluric profile in central Argentina, from which we infer enhanced electrical conductivity along the eastern side of the plunging slab, indicative of the presence of partial melt. This conductivity structure may imply that partial melting occurs to at least 250 km and perhaps to more than 400 km depth, or that melt is supplied from the 410 km discontinuity, consistent with the transition-zone 'water-filter' model of Bercovici and Karato. PMID:15164059

  11. Liquid sampling system

    DOEpatents

    Larson, Loren L. (Idaho Falls, ID)

    1987-01-01

    A conduit extends from a reservoir through a sampling station and back to the reservoir in a closed loop. A jet ejector in the conduit establishes suction for withdrawing liquid from the reservoir. The conduit has a self-healing septum therein upstream of the jet ejector for receiving one end of a double-ended cannula, the other end of which is received in a serum bottle for sample collection. Gas is introduced into the conduit at a gas bleed between the sample collection bottle and the reservoir. The jet ejector evacuates gas from the conduit and the bottle and aspirates a column of liquid from the reservoir at a high rate. When the withdrawn liquid reaches the jet ejector the rate of flow therethrough reduces substantially and the gas bleed increases the pressure in the conduit for driving liquid into the sample bottle, the gas bleed forming a column of gas behind the withdrawn liquid column and interrupting the withdrawal of liquid from the reservoir. In the case of hazardous and toxic liquids, the sample bottle and the jet ejector may be isolated from the reservoir and may be further isolated from a control station containing remote manipulation means for the sample bottle and control valves for the jet ejector and gas bleed.

  12. Liquid sampling system

    DOEpatents

    Larson, L.L.

    1984-09-17

    A conduit extends from a reservoir through a sampling station and back to the reservoir in a closed loop. A jet ejector in the conduit establishes suction for withdrawing liquid from the reservoir. The conduit has a self-healing septum therein upstream of the jet ejector for receiving one end of a double-ended cannula, the other end of which is received in a serum bottle for sample collection. Gas is introduced into the conduit at a gas bleed between the sample collection bottle and the reservoir. The jet ejector evacuates gas from the conduit and the bottle and aspirates a column of liquid from the reservoir at a high rate. When the withdrawn liquid reaches the jet ejector the rate of flow therethrough reduces substantially and the gas bleed increases the pressure in the conduit for driving liquid into the sample bottle, the gas bleed forming a column of gas behind the withdrawn liquid column and interrupting the withdrawal of liquid from the reservoir. In the case of hazardous and toxic liquids, the sample bottle and the jet ejector may be isolated from the reservoir and may be further isolated from a control station containing remote manipulation means for the sample bottle and control valves for the jet ejector and gas bleed. 5 figs.

  13. Complex C: A Low-Metallicity High-Velocity Cloud Plunging into the Milky Way

    E-print Network

    T. M. Tripp; B. P. Wakker; E. B. Jenkins; C. W. Bowers; A. C. Danks; R. F. Green; S. R. Heap; C. L. Joseph; M. E. Kaiser; J. L. Linsky; B. E. Woodgate

    2003-02-25

    (Abridged) We present a new high-resolution (7 km/s FWHM) echelle spectrum of 3C 351 obtained with STIS. 3C 351 lies behind the low-latitude edge of high-velocity cloud Complex C, and the new spectrum provides accurate measurements of O I, Si II, Al II, Fe II, and Si III absorption lines at the velocity of the HVC. We use collisional and photoionization models to derive ionization corrections; in both models we find that the overall metallicity Z = 0.1 - 0.3 Z_{solar} in Complex C, but nitrogen must be underabundant. The iron abundance indicates that Complex C contains very little dust. The absorbing gas probably is not gravitationally confined. The gas could be pressure-confined by an external medium, but alternatively we may be viewing the leading edge of the HVC, which is ablating and dissipating as it plunges into the Milky Way. O VI column densities observed with FUSE toward nine QSOs/AGNs behind Complex C support this conclusion: N(O VI) is highest near 3C 351, and the O VI/H I ratio increases substantially with decreasing latitude, suggesting that the lower-latitude portion of the cloud is interacting more vigorously with the Galaxy. The other sight lines through Complex C show some dispersion in metallicity, but with the current uncertainties, the measurements are consistent with a constant metallicity throughout the HVC. However, all of the Complex C sight lines require significant nitrogen underabundances. Finally, we compare the 3C 351 sight line to the sight line to the nearby QSO H1821+643 to search for evidence of outflowing Galactic fountain gas that could be mixing with Complex C. We find that the intermediate-velocity gas detected toward 3C 351 and H1821+643 has a higher metallicity and may well be a fountain/chimney outflow from the Perseus spiral arm.

  14. Axial jet mixing of ethanol in cylindrical containers during weightlessness

    NASA Technical Reports Server (NTRS)

    Aydelott, J. C.

    1979-01-01

    An experimental program was conducted to examine the liquid flow patterns that result from the axial jet mixing of ethanol in 10-centimeter-diameter cylindrical tanks in weightlessness. A convex hemispherically ended tank and two Centaur liquid-hydrogen-tank models were used for the study. Four distinct liquid flow patterns were observed to be a function of the tank geometry, the liquid-jet velocity, the volume of liquid in the tank, and the location of the tube from which the liquid jet exited.

  15. Axial jet mixing of ethanol in spherical containers during weightlessness

    NASA Technical Reports Server (NTRS)

    Audelott, J. C.

    1976-01-01

    An experimental program was conducted to examine the liquid flow patterns that result from the axial jet mixing of ethanol in 10-centimeter-diameter spherical containers in weightlessness. Complete liquid circulation flow patterns were easily established in containers that were less than half full of liquid, while for higher liquid fill conditions, vapor was drawn into the inlet of the simulated mixer unit. Increasing the liquid-jet or lowering the position at which the liquid jet entered the container caused increasing turbulence and bubble formation.

  16. REVIVAL OF MAMMALIAN SPERM AFTER IMMERSION IN LIQUID NITROGEN

    PubMed Central

    Hoagland, Hudson; Pincus, Gregory

    1942-01-01

    1. A wide variety of procedures was used to test the motility of mammalian sperm after plunging them into liquid nitrogen at –195°C. and later rapidly warming them to 35°C. by plunging them into a suitable balanced and isotonic medium. 2. Using seminal fluid sperm from the same human donor, maximal numbers of motile sperm survived vitrification when the samples were (a) very fresh, (b) untreated with plasmolysing solutions, (c) plunged into the refrigerant in the form of a foam. The maximum yield of motile human sperm recoverable from the liquid nitrogen was 50 per cent. Since in this sample only 75 per cent of the sperm were alive before immersion, 67 per cent of the living sperm survived vitrification. 3. Experiments with sperm from 31 rabbits were made with a variety of conditions of pretreatment to obtain maximal yields of recoverable, motile sperm after vitrification by liquid nitrogen. (a) A consistent recoverable yield of about 0.5 per cent was obtained when the untreated suspension of sperm was smeared on cellophane and partially dried in air before immersing in liquid nitrogen. (b) On a few out of many occasions plasmolysis for several minutes with hypertonic Ringer solution gave a recoverable yield of 0.1 per cent as did (c) pretreatment with hypertonic Ringer and butyric acid. PMID:19873277

  17. The flow structure in the near field of jets and its effect on cavitation inception, and, Implementation of ferroelectric liquid crystal and birefringent crystal for image shifting in particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Gopalan, Shridhar

    1999-10-01

    Cavitation experiments performed in the near field of a 50-mm diameter (D) jet at ReD = 5 × 105, showed inception in the form of inclined ``cylindrical'' bubbles at axial distances (x/D) less than 0.55, with indices of 2.5. On tripping the boundary layer, cavitation inception occurred at x/D ~ 2, as distorted ``spherical'' bubbles with inception indices of 1.7. To investigate these substantial differences, the near field of the jet was measured using Particle Image Velocimetry (PIV). Data on the primary flow, the strength distribution of the ``streamwise''vortices and the velocity profiles within the initial boundary layers were obtained. The untripped case showed a direct transition to three-dimensional flow in the near field (x/D < 0.7) even before rolling up to distinct vortex rings. Strong ``streamwise'' vortices with strengths up to 25% of the jet velocity times the characteristic wavelength were seen. Cavitation inception occurred in the core of these vortices. In contrast, in the tripped jet the vortex sheet rolled up to the familiar Kelvin- Helmholtz vortex rings with weak secondary vortices. Using the measured nuclei distribution, strengths and straining of the ``streamwise'' structures, the rates of cavitation events were estimated. The estimated results match very well with the measured cavitation rates. Also, the Reynolds stresses in the near field of the jet show similar trends and magnitudes to those of Browand & Latigo (1979) and Bell & Mehta (1990) for a plane shear layer. In the second part of this essay we discuss the implementation of electro-optical image shifting to resolve directional ambiguity in PIV measurements. The technique uses a ferroelectric liquid crystal (FLC) as an electro-optic half wave plate and a birefringent crystal (calcite) as the shifter. The system can be used with non-polarized light sources and fluorescent particles. The minimum shifting time is approximately 100?s. This compact electrooptical device usually is positioned in front of the camera lens, though it has also been mounted inside the lens body. This device extensively was used to acquire data in the near field of the jet, which is discussed in Chapter 2. Sample vector maps from a turbulent multidirectional flow are also included.

  18. Separation Of Liquid And Gas In Zero Gravity

    NASA Technical Reports Server (NTRS)

    Howard, Frank S.; Fraser, Wilson S.

    1991-01-01

    Pair of reports describe scheme for separating liquid from gas so liquid could be pumped. Designed to operate in absence of gravitation. Jet of liquid, gas, or liquid/gas mixture fed circumferentially into cylindrical tank filled with liquid/gas mixture. Jet starts liquid swirling. Swirling motion centrifugally separates liquid from gas. Liquid then pumped from tank at point approximately diametrically opposite point of injection of jet. Vortex phase separator replaces such devices as bladders and screens. Requires no components inside tank. Pumps for gas and liquid outside tank and easily accessible for maintenance and repairs.

  19. Rapid Confined Mixing with Transverse Jets Part 1: Single Jet

    NASA Astrophysics Data System (ADS)

    Salazar, David; Forliti, David

    2012-11-01

    Transverse jets have been studied extensively due to their relevance and efficiency in fluid mixing applications. Gas turbine burners, film cooling, and chemical reactors are some examples of rapid transverse jet mixing. Motivated by a lack of universal scaling laws for confined and unconfined transverse jets, a newly developed momentum transfer parameter was found to improve correlation of literature data. Jet column drag and entrainment arguments for momentum transfer are made to derive the parameter. A liquid-phase mixing study was conducted to investigate confined mixing for a low number of jets. Planar laser induced fluorescence was implemented to measure mixture fraction for a single confined transverse jet. Time-averaged cross-sectional images were taken with a light sheet located three diameters downstream of transverse injection. A mixture of water and sodium fluorescein was used to distinguish jet fluid from main flow fluid for the test section images. Image data suggest regimes for under- and overpenetration of jet fluid into the main flow. The scaling parameter is found to correlate optimum unmixedness for multiple diameter ratios at a parameter value of 0.75. Distribution A: Public Release, Public Affairs Clearance Number: 12655.

  20. Water Jetting

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Hi-Tech Inc., a company which manufactures water jetting equipment, needed a high pressure rotating swivel, but found that available hardware for the system was unsatisfactory. They were assisted by Marshall, which had developed water jetting technology to clean the Space Shuttles. The result was a completely automatic water jetting system which cuts rock and granite and removes concrete. Labor costs have been reduced; dust is suppressed and production has been increased.

  1. Centrifugal device separates liquid from gas

    NASA Technical Reports Server (NTRS)

    Handlewich, R. M.; Stroup, K. E.

    1965-01-01

    Liquid-to-gas ratio is reduced from maximum efficiency of jet engine fuel by a centrifugal separator. The amount of liquid removed from the fuel is controlled by the separator-screen mesh size and its rotational speed.

  2. Synthetic jets

    Microsoft Academic Search

    Ari Glezer; Michael Amitay

    2002-01-01

    The evolution of a synthetic (zero-net mass flux) jet and the flow mechanisms of its interaction with a cross flow are reviewed. An isolated synthetic jet is produced by the interactions of a train of vortices that are typically formed by alternating momentary ejection and suction of fluid across an orifice such that the net mass flux is zero. A

  3. U.S., non-U.S. outlays to rise in `98, but oil price plunge clouds spending outlook

    SciTech Connect

    Beck, R.J.

    1998-03-23

    Capital spending by oil and gas companies in and outside the US will rise in 1998, but that forecast may be jeopardized by the continuing plunge in oil prices. For operations in the US, oil and gas company capital spending is expected to move up in 1998 for the fourth year in a row. If the money is spent, it will be the highest industry investment level since 1985. Strong oil and gas prices and increased volumes have boosted company cash flow and profits the last few years, fueling increased spending. However, the near-term outlook has now been clouded by economic turmoil in a number of Asian countries and the recent collapse of oil prices. The paper discusses oil and gas prices, US upstream spending, US non-exploration and production spending, capital spending in Canada, and spending outside US and Canada.

  4. Influence of heat transfer on the aerodynamic performance of a plunging and pitching NACA0012 airfoil at low Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Hinz, Denis F.; Alighanbari, Hekmat; Breitsamter, Christian

    2013-02-01

    The unsteady low Reynolds number aerodynamics phenomena around flapping wings are addressed in several investigations. Elsewhere, airfoils at higher Mach numbers and Reynolds numbers have been treated quite comprehensively in the literature. It is duly noted that the influence of heat transfer phenomena on the aerodynamic performance of flapping wings configurations is not well studied. The objective of the present study is to investigate the effect of heat transfer upon the aerodynamic performance of a pitching and plunging NACA0012 airfoil in the low Reynolds number flow regime with particular emphasis upon the airfoil's lift and drag coefficients. The compressible Navier-Stokes equations are solved using a finite volume method. To consider the variation of fluid properties with temperature, the values of dynamic viscosity and thermal diffusivity are evaluated with Sutherland's formula and the Eucken model, respectively. Instantaneous and mean lift and drag coefficients are calculated for several temperature differences between the airfoil surface and freestream within the range 0-100 K. Simulations are performed for a prescribed airfoil motion schedule and flow parameters. It is learnt that the aerodynamic performance in terms of the lift CL and drag CD behavior is strongly dependent upon the heat transfer rate from the airfoil to the flow field. In the plunging case, the mean value of CD tends to increase, whereas the amplitude of CL tends to decrease with increasing temperature difference. In the pitching case, on the other hand, the mean value and the amplitude of both CD and CL decrease. A spectral analysis of CD and CL in the pitching case shows that the amplitudes of both CD and CL decrease with increasing surface temperature, whereas the harmonic frequencies are not affected.

  5. Shock-Wave-Induced Jetting of Micron-Size Bubbles C. D. Ohl* and R. Ikink

    E-print Network

    Ohl, Claus-Dieter

    of the jet tip increases and a lower estimate of the averaged jet velocity increases linearly from 20 to 150Shock-Wave-Induced Jetting of Micron-Size Bubbles C. D. Ohl* and R. Ikink Department of Applied in water with radii between 7 and 55 m subjected to a shock wave exhibit a liquid jetting phenomenon

  6. Direct Liquid Cooling of High Flux Micro and Nano Electronic Components Boiling, evaporation, jet, and spray cooling, by suitable liquids such as fluorocarbons, might serve to control chip hot-spots and overheating

    Microsoft Academic Search

    Avram Bar-Cohen; Mehmet Arik; Michael Ohadi

    The inexorable rise in chip power dissipation and emergence of on-chip hot spots with heat fluxes approaching 1k W\\/cm 2 has turned renewed attention to direct cooling with dielectric liquids. Use of dielectric liquids in intimate contact with the heat dissipating surfaces eliminates the deleterious effects of solid-solid interface resistances and harnesses the highly efficient phase-change processes to the critical

  7. The effect of turbulence on the stability of liquid jets and the resulting droplet size distributions. Fourth quarterly technical report, October 1, 1993--December 31, 1993

    SciTech Connect

    Mansour, A.; Chigier, N.

    1993-12-31

    In this progress report the authors report on progress in making experimental measurements to describe the rheological properties of non-Newtonian fluids. Non-Newtonian liquids exhibit a non linear relationship between the shear stress and the shear rate. A typical time-dependent rheological phenomenon is thixotropy. Thixotropic fluids show a limited decrease in the shear viscosity of the fluid with time under a suddenly applied constant stress. Thixotropic fluids also show a hysteresis loop and a decaying stress on the shear stress-shear rate plot. Here the authors are using a power law model to describe the behavior of such non-Newtonian liquids.

  8. Zero gravity liquid mixer

    NASA Technical Reports Server (NTRS)

    Booth, F. W.; Bruce, R. A. (inventors)

    1973-01-01

    An apparatus for mixing liquids under conditions of zero gravity is disclosed. The apparatus is comprised of a closed reservoir for the liquids, with a means for maintaining a positive pressure on the liquids in the reservoir. A valved liquid supply line is connected to the reservoir for supplying the reservoir with the liquids to be mixed in the reservoir. The portion of the reservoir containing the liquids to be mixed is in communication with a pump which alternately causes a portion of the liquids to flow out of the pump and into the reservoir to mix the liquids. The fluids in the reservoir are in communication through a conduit with the pump which alternately causes a portion of the fluids to flow out of the pump and into the sphere. The conduit connecting the pump and sphere may contain a nozzle or other jet-forming structure such as a venturi for further mixing the fluids.

  9. Business Jet

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Citation Jet, developed by Cessna Aircraft Company, Wichita, KS, is the first business jet to employ Langley Research Center's natural laminar flow (NLF) technology. NLF reduces drag and therefore saves fuel by using only the shape of the wing to keep the airflow smooth, or laminar. This reduces friction between the air and wing, and therefore, reduces drag. NASA's Central Industrial Applications Center, Rural Enterprises, Inc., Durant, OK, its Kansas affiliate, and Wichita State University assisted in the technology transfer.

  10. Emerging Jets

    E-print Network

    Pedro Schwaller; Daniel Stolarski; Andreas Weiler

    2015-05-11

    In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilities for discovery at LHCb are also discussed.

  11. Emerging jets

    NASA Astrophysics Data System (ADS)

    Schwaller, Pedro; Stolarski, Daniel; Weiler, Andreas

    2015-05-01

    In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilities for discovery at LHCb are also discussed.

  12. Emerging Jets

    E-print Network

    Schwaller, Pedro; Weiler, Andreas

    2015-01-01

    In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilit...

  13. Ultra-rapid freezing by spraying/plunging: pre-cooling in the cold gaseous layer.

    PubMed

    Chang, Z H; Baust, J G

    1991-03-01

    A thermophysical model is established to analyse the influence of pre-cooling of a biological specimen in the cold gas layer associated with spray-freezing techniques. The basic principles governing the process of pre-cooling are provided. It is concluded that pre-cooling is one of the major limiting steps in attaining an overall ultra-rapid cooling rate. Pre-cooling has a substantial influence on the nature of the final frozen specimens. In order completely to avoid crystallization before entry into the liquid cryogen and maximize the overall cooling rate of the specimen, precautions should be taken to control the height of the gaseous layer and the size of the specimen. The probability of the specimen being frozen in the cold gaseous layer is reduced by increasing the entry speed. The effectiveness, however, becomes less marked at speeds greater than 10 m s. In order to minimize the risk of misinterpreting the measured cooling rate, it is necessary to specify the pre-cooling conditions. The pre-cooling effect is much more evident in liquid helium than in cryogens such as propane, ethane, Freon 12, 13 and 22. PMID:2046089

  14. Breakup of Liquid Filaments

    E-print Network

    Castrejon-Pita, Alfonso A.; Castrejon-Pita, J.R.; Hutchings, I.M.

    2012-01-01

    in the formation of droplets from a thin water stream trickling from a tap, and in the quite different behaviour of the more viscous threads of honey or syrup flowing from a spoon [1]. The break- up of liquid jets is important in several practical con- texts... , including the dispersion of liquid drugs into res- pirable droplets, microfluidics, crop- and paint-spraying, and ink-jet printing [2–4]. There are also biological sys- tems in which either long filaments remain intact, or many droplets are formed [5, 6...

  15. Bed-tilt, fold-plunge correction and statistical analysis of paleocurrents using Lotus 1-2-3

    SciTech Connect

    Mustard, P.S. (Carleton Univ., Ottawa, Ontario (Canada))

    1989-06-01

    Most geoscientists do not want to invest time or money in endless software acquisitions, nor are they expert enough with programming languages to write their own programs. One way to avoid this is to use the power of the spreadsheet software many geoscientists are already familiar with. This paper presents three spreadsheet templates for Lotus 1-2-3 (but transferable to most spreadsheet packages) that are useful to any geologist who uses paleocurrent or other trend data. ROTATE.WK1 calculates bed-tilt and fold plunge corrections of planar orientation data (cross-stratification or imbrication for example). LINROT.WK1 calculates these corrections for linear orientation data (groove trends for example). VECTMEAN.WK1 takes orientation data and calculates frequency distribution, vector mean and other statistical measures commonly used in paleocurrent studies. It is hoped these templates not only will be useful in themselves, but will encourage geoscientists to harness the power of the spreadsheet software they already own and understand, rather then spending time and money on new software.

  16. High Resolution Simulations of the Plunging Region in a Pseudo-Newtonian Potential: Dependence on Numerical Resolution and Field Topology

    E-print Network

    John F. Hawley; Julian H. Krolik

    2001-10-04

    New three dimensional magnetohydrodynamic simulations of accretion disk dynamics in a pseudo-Newtonian Paczynski-Wiita potential are presented. These have finer resolution in the inner disk than any previously reported. Finer resolution leads to increased magnetic field strength, greater accretion rate, and greater fluctuations in the accretion rate. One simulation begins with a purely poloidal magnetic field, the other with a purely toroidal field. Compared to the poloidal initial field simulation, a purely toroidal initial field takes longer to reach saturation of the magnetorotational instability and produces less turbulence and weaker magnetic field energies. For both initial field configurations, magnetic stresses continue across the marginally stable orbit; measured in units corresponding to the Shakura-Sunyaev alpha parameter, the stress grows from ~0.1 in the disk body to as much as ~10 deep in the plunging region. Matter passing the inner boundary of the simulation has ~10% greater binding energy and ~10% smaller angular momentum than it did at the marginally stable orbit. Both the mass accretion rate and the integrated stress fluctuate widely on a broad range of timescales.

  17. Meson Production Simulations for a Mercury Jet Target

    SciTech Connect

    Ding, X.; Cline, D. [Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, California 90095 (United States); Kirk, H.; Berg, J. S. [Brookhaven National Laboratory, Upton, New York 11973 (United States)

    2010-03-30

    A study of target parameters for a high-power, liquid mercury jet target system for a neutrino factory or muon collider is presented. Using the MARS15 code, we simulate particle production initiated by incoming protons below the jet with kinetic energies between 2 and 100 GeV. For each proton beam energy, we maximize production by varying the geometric parameters of the target: the mercury jet radius, the incoming proton beam angle, and the crossing angle between the mercury jet and the proton beam. With an 8 GeV proton beam, we study the variation of meson production with the direction of the proton beam relative to the jet.

  18. Gas Jets

    NASA Technical Reports Server (NTRS)

    Chaplygin, S.

    1944-01-01

    A brief summary of the contents of this paper is presented here. In part I the differential equations of the problem of a gas flow in two dimensions is derived and the particular integrals by which the problem on jets is solved are given. Use is made of the same independent variables as Molenbroek used, but it is found to be more suitable to consider other functions. The stream function and velocity potential corresponding to the problem are given in the form of series. The investigation on the convergence of these series in connection with certain properties of the functions entering them forms the subject of part II. In part III the problem of the outflow of a gas from an infinite vessel with plane walls is solved. In part IV the impact of a gas jet on a plate is considered and the limiting case where the jet expands to infinity changing into a gas flow is taken up in more detail. This also solved the equivalent problem of the resistance of a gaseous medium to the motion of a plate. Finally, in part V, an approximate method is presented that permits a simpler solution of the problem of jet flows in the case where the velocities of the gas (velocities of the particles in the gas) are not very large.

  19. Electrohydrodynamic (EHD) stimulation of jet breakup

    NASA Technical Reports Server (NTRS)

    Crowley, J. M.

    1982-01-01

    Electrohydrodynamic (EHD) excitation of liquid jets offers an alternative to piezoelectric excitation without the complex frequency response caused by piezoelectric and mechanical resonances. In an EHD exciter, an electrode near the nozzle applies an alternating Coulomb force to the jet surface, generating a disturbance which grows until a drop breaks off downstream. This interaction is modelled quite well by a linear, long wave model of the jet together with a cylindrical electric field. The breakup length, measured on a 33 micrometer jet, agrees quite well with that predicted by the theory, and increases with the square of the applied voltage, as expected. In addition, the frequency response is very smooth, with pronounced nulls occurring only at frequencies related to the time which the jet spends inside the exciter.

  20. Water jet rebounds on hydrophobic surfaces : a first step to jet micro-fluidics

    E-print Network

    Franck Celestini; R. Kofman; Xavier Noblin; Mathieu Pellegrin

    2010-09-28

    When a water jet impinges upon a solid surface it produces a so called hydraulic jump that everyone can observe in the sink of its kitchen. It is characterized by a thin liquid sheet bounded by a circular rise of the surface due to capillary and gravitational forces. In this phenomenon, the impact induces a geometrical transition, from the cylindrical one of the jet to the bi-dimensional one of the film. A true jet rebound on a solid surface, for which the cylindrical geometry is preserved, has never been yet observed. Here we experimentally demonstrate that a water jet can impact a solid surface without being destabilized. Depending on the incident angle of the impinging jet, its velocity and the degree of hydrophobicity of the substrate, the jet can i) bounce on the surface with a fixed reflected angle, ii) land on it and give rise to a supported jet or iii) be destabilized, emitting drops. Capillary forces are predominant at the sub-millimetric jet scale considered in this work, along with the hydrophobic nature of the substrate. The results presented in this letter raise the fundamental problem of knowing why such capillary hydraulic jump gives rise to this unexpected jet rebound phenomenon. This study furthermore offers new and promising possibilities to handle little quantity of water through "jet micro-fluidics"

  1. Turbulent Jets?

    NASA Astrophysics Data System (ADS)

    Wilde, B. H.; Rosen, P. A.; Foster, J. M.; Perry, T. S.; Steinkamp, M. J.; Robey, H. F.; Khokhlov, A. M.; Gittings, M. L.; Coker, R. F.; Keiter, P. A.; Knauer, J. P.; Drake, R. P.; Remington, B. A.; Bennett, G. R.; Sinars, D. B.; Campbell, R. B.; Mehlhorn, T. A.

    2003-10-01

    Over the last few years we have fielded numerous supersonic jet experiments on the NOVA and OMEGA lasers and Sandia's pulsed-power Z-machine in a collaboration between Los Alamos National Laboratory, the Atomic Weapons Establishment, Lawrence Livermore National Laboratory, and Sandia National Laboratory. These experiments are being conducted to help validate our radiation-hydrodynamic codes, especially the newly developing ASC codes. One of the outstanding questions is whether these types of jets should turn turbulent given their high Reynolds number. Recently we have modified our experiments to have more Kelvin-Helmholtz shear, run much later in time and therefore have a better chance of going turbulent. In order to diagnose these large (several mm) jets at very late times ( 1000 ns) we are developing point-projection imaging on both the OMEGA laser, the Sandia Z-Machine, and ultimately at NIF. Since these jets have similar Euler numbers to jets theorized to be produced in supernovae explosions, we are also collaborating with the astrophysics community to help in the validation of their new codes. This poster will present a review of the laser and pulsed-power experiments and a comparison of the data to simulations by the codes from the various laboratories. We will show results of simulations wherein these jets turn highly 3-dimensional and show characteristics of turbulence. With the new data, we hope to be able to validate the sub-grid-scale turbulent mix models (e. g. BHR) that are being incorporated into our codes.*This work is performed under the auspices of the U. S. Department of Energy by the Los Alamos National Laboratory Laboratory under Contract No. W-7405-ENG-36, Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48, the Laboratory for Laser Energetics under Contract No. DE-FC03-92SF19460, Sandia National Laboratories under Contract No. DE-AC04-94AL85000, the Office of Naval Research, and the NASA Astrophysical Theory Grant.

  2. Dichotomy of Solar Coronal Jets: Standard Jets and Blowout Jets

    NASA Technical Reports Server (NTRS)

    Moore, R. L.; Cirtain, J. W.; Sterling, A. C.; Falconer, D. A.

    2010-01-01

    By examining many X-ray jets in Hinode/XRT coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H alpha macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major CMEs. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 Angstrom snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T 10(exp 4) - 10(exp 5) K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

  3. Jets from compact objects

    E-print Network

    H. C. Spruit

    2000-03-03

    Some topics in the theory of jets are reviewed. These include jet precession, unconfined jets, the origin of knots, the internal shock model as a unifying theme from protostellar jets to Gamma-ray bursts, relations between the Blandford-Znajek and MHD disk-wind models, and jet collimation in magnetic acceleration models.

  4. Liquid Wall Chambers

    SciTech Connect

    Meier, W R

    2011-02-24

    The key feature of liquid wall chambers is the use of a renewable liquid layer to protect chamber structures from target emissions. Two primary options have been proposed and studied: wetted wall chambers and thick liquid wall (TLW) chambers. With wetted wall designs, a thin layer of liquid shields the structural first wall from short ranged target emissions (x-rays, ions and debris) but not neutrons. Various schemes have been proposed to establish and renew the liquid layer between shots including flow-guiding porous fabrics (e.g., Osiris, HIBALL), porous rigid structures (Prometheus) and thin film flows (KOYO). The thin liquid layer can be the tritium breeding material (e.g., flibe, PbLi, or Li) or another liquid metal such as Pb. TLWs use liquid jets injected by stationary or oscillating nozzles to form a neutronically thick layer (typically with an effective thickness of {approx}50 cm) of liquid between the target and first structural wall. In addition to absorbing short ranged emissions, the thick liquid layer degrades the neutron flux and energy reaching the first wall, typically by {approx}10 x x, so that steel walls can survive for the life of the plant ({approx}30-60 yrs). The thick liquid serves as the primary coolant and tritium breeding material (most recent designs use flibe, but the earliest concepts used Li). In essence, the TLW places the fusion blanket inside the first wall instead of behind the first wall.

  5. Jet Flows Around Microbubbles In Subcooled Boiling , Xiaofeng Pengb

    E-print Network

    Kihm, IconKenneth David

    Jet Flows Around Microbubbles In Subcooled Boiling Hao Wanga , Xiaofeng Pengb , David M nucleate boiling. The flow velocities were visualized with high-speed photography and quantified with a PIV flow at cool regions on the bubble sides resulting from upward flow of subcooled liquid. Bubble-top jet

  6. Separation of gas from liquid in a two-phase flow system

    NASA Technical Reports Server (NTRS)

    Hayes, L. G.; Elliott, D. G.

    1973-01-01

    Separation system causes jets which leave two-phase nozzles to impinge on each other, so that liquid from jets tends to coalesce in center of combined jet streams while gas phase is forced to outer periphery. Thus, because liquid coalescence is achieved without resort to separation with solid surfaces, cycle efficiency is improved.

  7. Dielectric coating dynamics in electrified coaxial jets

    NASA Astrophysics Data System (ADS)

    Marin, Alvaro G.; Loscertales, Ignacio G.; Barrero, Antonio

    2006-11-01

    Electrified coaxial jets generated from compound electrified menisci (compound electrosprays) have demonstrated their ability to produce particles with complex core-shell structure (I.G. Loscertales et al., Science, 295, 1695 (2002); JACS, 126, 5376 (2004)). Since at least one of the liquids forming the compound meniscus must be relatively conductive, two configurations are possible: the conducting liquid being in or out. In this work we shall consider the first configuration, whose applications range from simple protection of volatile liquids by non-volatile dielectric liquids to encapsulation by using dielectric polymer melts. Although the scaling law for the electric current transported by the electrified coaxial jets has been recently investigated (Lopez-Herrera et al.,JAS ,34, 535 (2003)), the dynamics of the coating layer is still not completely understood. The aim of this communication is to gain insight on the dependence of the coating thickness on the injected liquid flow rates, the viscosities of both liquids and surface tensions (liquid-liquid and liquid-air).

  8. Optical Diagnostics of Mercury Jet for an Intense Proton Target , T. Tsang2

    E-print Network

    McDonald, Kirk

    melt or crack a stationary solid high-Z target. Hence, a recyclable moving liquid mercury (Hg) jetA070841 Optical Diagnostics of Mercury Jet for an Intense Proton Target H. Park1 , T. Tsang2 , H. G is designed and constructed for imaging a free mercury jet interact- ing with a high intensity proton beam

  9. Jet energy scale determination in the D0 experiment

    NASA Astrophysics Data System (ADS)

    Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Askew, A.; Atkins, S.; Augsten, K.; Avila, C.; Badaud, F.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barberis, E.; Baringer, P.; Bartlett, J. F.; Bassler, U.; Bazterra, V.; Bean, A.; Begalli, M.; Bellantoni, L.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Blazey, G.; Blessing, S.; Bloom, K.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Borysova, M.; Brandt, A.; Brandt, O.; Brock, R.; Bross, A.; Brown, D.; Bu, X. B.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Buszello, C. P.; Camacho-Pérez, E.; Casey, B. C. K.; Castilla-Valdez, H.; Caughron, S.; Chakrabarti, S.; Chan, K. M.; Chandra, A.; Chapon, E.; Chen, G.; Cho, S. W.; Choi, S.; Choudhary, B.; Cihangir, S.; Claes, D.; Clutter, J.; Cooke, M.; Cooper, W. E.; Corcoran, M.; Couderc, F.; Cousinou, M.-C.; Cutts, D.; Das, A.; Davies, G.; de Jong, S. J.; De La Cruz-Burelo, E.; Déliot, F.; Demina, R.; Denisov, D.; Denisov, S. P.; Desai, S.; Deterre, C.; DeVaughan, K.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dominguez, A.; Dubey, A.; Dudko, L. V.; Duperrin, A.; Dutt, S.; Eads, M.; Edmunds, D.; Ellison, J.; Elvira, V. D.; Enari, Y.; Evans, H.; Evdokimov, V. N.; Feng, L.; Ferbel, T.; Fiedler, F.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Fortner, M.; Fox, H.; Fuess, S.; Garbincius, P. H.; Garcia-Bellido, A.; García-González, J. A.; Gavrilov, V.; Geng, W.; Gerber, C. E.; Gershtein, Y.; Ginther, G.; Golovanov, G.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grünendahl, S.; Grünewald, M. W.; Guillemin, T.; Gutierrez, G.; Gutierrez, P.; Haley, J.; Han, L.; Harder, K.; Harel, A.; Hauptman, J. M.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hoeneisen, B.; Hogan, J.; Hohlfeld, M.; Holzbauer, J. L.; Howley, I.; Hubacek, Z.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Ito, A. S.; Jabeen, S.; Jaffré, M.; Jayasinghe, A.; Jeong, M. S.; Jesik, R.; Jiang, P.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jonsson, P.; Joshi, J.; Jung, A. W.; Juste, A.; Kajfasz, E.; Karmanov, D.; Katsanos, I.; Kehoe, R.; Kermiche, S.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kiselevich, I.; Kohli, J. M.; Kozelov, A. V.; Kraus, J.; Kumar, A.; Kupco, A.; Kur?a, T.; Kuzmin, V. A.; Lammers, S.; Lebrun, P.; Lee, H. S.; Lee, S. W.; Lee, W. M.; Lei, X.; Lellouch, J.; Li, D.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipton, R.; Liu, H.; Liu, Y.; Lobodenko, A.; Lokajicek, M.; Lopes de Sa, R.; Luna-Garcia, R.; Lyon, A. L.; Maciel, A. K. A.; Madar, R.; Magaña-Villalba, R.; Makovec, N.; Malik, S.; Malyshev, V. L.; Mansour, J.; Martínez-Ortega, J.; McCarthy, R.; McGivern, C. L.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Meyer, A.; Meyer, J.; Miconi, F.; Mondal, N. K.; Mulhearn, M.; Nagy, E.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Neustroev, P.; Nguyen, H. T.; Nunnemann, T.; Orduna, J.; Osman, N.; Osta, J.; Pal, A.; Parashar, N.; Parihar, V.; Park, S. K.; Partridge, R.; Parua, N.; Patwa, A.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Pleier, M.-A.; Podstavkov, V. M.; Popov, A. V.; Prewitt, M.; Price, D.; Prokopenko, N.; Ochando, C.; Qian, J.; Quadt, A.; Quinn, B.; Raja, R.; Ratoff, P. N.; Razumov, I.; Ripp-Baudot, I.; Rizatdinova, F.; Rominsky, M.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Sajot, G.; Sánchez-Hernández, A.; Sanders, M. P.; Santos, A. S.; Savage, G.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schwanenberger, C.; Schwienhorst, R.; Sekaric, J.; Severini, H.; Shabalina, E.; Shary, V.; Shaw, S.; Shchukin, A. A.; Simak, V.; Skubic, P.; Slattery, P.; Smirnov, D.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Sonnenschein, L.; Soustruznik, K.; Stark, J.; Stoyanova, D. A.; Strauss, M.; Suter, L.; Svoisky, P.; Titov, M.; Tokmenin, V. V.; Tsai, Y.-T.; Tsybychev, D.; Tuchming, B.; Tully, C.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vasilyev, I. A.; Verkheev, A. Y.; Vertogradov, L. S.; Verzocchi, M.; Vesterinen, M.; Vilanova, D.; Vokac, P.; Wahl, H. D.; Wang, M. H. L. S.; Warchol, J.; Watts, G.; Wayne, M.; Weichert, J.; Welty-Rieger, L.; Williams, M. R. J.; Wilson, G. W.; Wobisch, M.; Wood, D. R.; Wyatt, T. R.; Xie, Y.; Yamada, R.; Yang, S.; Yasuda, T.; Yatsunenko, Y. A.; Ye, W.; Ye, Z.; Yin, H.; Yip, K.

    2014-11-01

    The calibration of jet energy measured in the D0 detector is presented, based on ppbar collisions at a center-of-mass energy of 1.96 TeV at the Fermilab Tevatron collider. Jet energies are measured using a sampling calorimeter composed of uranium and liquid argon as the passive and active media, respectively. This paper describes the energy calibration of jets performed with ?+jet, Z+jet and dijet events, with jet transverse momentum pT>6 GeV and pseudorapidity range |?|<3.6. The corrections are measured separately for data and simulation, achieving a precision of 1.4-1.8% for jets in the central part of the calorimeter and up to 3.5% for the jets with pseudorapidity |?|=3.0. Specific corrections are extracted to enhance the description of jet energy in simulation and in particular of the effects due to the flavor of the parton originating the jet, correcting biases up to 3-4% in jets with low pT originating from gluons and up to 6-8% in jets from b quarks.

  10. Oscillatory system of the jet electromagnetic vibrator

    NASA Astrophysics Data System (ADS)

    Bogdanov, E.; Rikkonen, S.; Nomokonova, Yu

    2014-10-01

    The article describes the system of nonlinear differential equations of the jet electromagnetic vibrator, designed to activate Newtonian and non-Newtonian fluids. The authors formulated the principles of designing electrical and hydro-mechanical components of the device based on the viscosity and density of the process liquid. The article describes experimental frequency characteristics of the system for liquids with the different rheological properties.

  11. Inclusive Jets in PHP

    NASA Astrophysics Data System (ADS)

    Roloff, P.

    Differential inclusive-jet cross sections have been measured in photoproduction for boson virtualities Q^2 < 1 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 300 pb^-1. Jets were identified in the laboratory frame using the k_T, anti-k_T or SIScone jet algorithms. Cross sections are presented as functions of the jet pseudorapidity, eta(jet), and the jet transverse energy, E_T(jet). Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low E_T(jet) and high eta(jet). The cross sections have the potential to improve the determination of the PDFs in future QCD fits. Values of alpha_s(M_Z) have been extracted from the measurements based on different jet algorithms. In addition, the energy-scale dependence of the strong coupling was determined.

  12. The Middle School Plunge

    ERIC Educational Resources Information Center

    West, Martin; Schwerdt, Guido

    2012-01-01

    Policymakers nationwide continue to wrestle with a basic question: At what grade level should students move to a new school? In the most common grade configuration in American school districts, public school students make two school transitions, entering a middle school in grade 6 or 7 and a high school in grade 9. This pattern reflects the…

  13. Taking the Plunge.

    ERIC Educational Resources Information Center

    Hatch, Stanley

    1987-01-01

    Describes why lake hikes practiced at Girl Scout Camp Bonnie Brae (Massachusetts) are an ideal camp activity to teach aquatic ecology and engage the senses. Discusses program benefits: camper/counselor interaction, personal and group challenge, and conflict resolution. (NEC)

  14. Universal scaling law for jets of collapsing bubbles.

    PubMed

    Obreschkow, D; Tinguely, M; Dorsaz, N; Kobel, P; de Bosset, A; Farhat, M

    2011-11-11

    Cavitation bubbles collapsing and rebounding in a pressure gradient ?p form a "microjet" enveloped by a "vapor jet." This Letter presents unprecedented observations of the vapor jets formed in a uniform gravity-induced ?p, modulated aboard parabolic flights. The data uncover that the normalized jet volume is independent of the liquid density and viscosity and proportional to ? ? |?p|R(0)/?p, where R(0) the maximal bubble radius and ?p is the driving pressure. A derivation inspired by "Kelvin-Blake" considerations confirms this law and reveals its negligible dependence of surface tension. We further conjecture that the jet only pierces the bubble boundary if ? ? 4 × 10(-4). PMID:22181734

  15. Supersonic Jet Control

    Microsoft Academic Search

    Mo Samimy

    2004-01-01

    Supersonic jets could be controlled via various means, for example, by imparting streamwise vorticity into the jet or by exciting one of the jet instabilities. The jet control in the first category has been achieved mostly passively through the use of vortex generating tabs or chevrons. The primary mechanism in such a device is spanwise\\/azimuthal pressure gradient imposed by the

  16. Sessile drop deformations under an impinging jet

    NASA Astrophysics Data System (ADS)

    Feng, James Q.

    2015-06-01

    The problem of steady axisymmetric deformations of a liquid sessile drop on a flat solid surface under an impinging gas jet is of interest for understanding the fundamental behavior of free surface flows as well as for establishing the theoretical basis in process design for the Aerosol {Jet^{circledR}} direct-write technology. It is studied here numerically using a Galerkin finite-element method, by computing solutions of Navier-Stokes equations. For effective material deposition in Aerosol {Jet^{circledR}} printing, the desired value of Reynolds number for the laminar gas jet is found to be greater than 500. The sessile drop can be severely deformed by an impinging gas jet when the capillary number is approaching a critical value beyond which no steady axisymmetric free surface deformation can exist. Solution branches in a parameter space show turning points at the critical values of capillary number, which typically indicate the onset of free surface shape instability. By tracking solution branches around turning points with an arc-length continuation algorithm, critical values of capillary number can be accurately determined. Near turning points, all the free surface profiles in various parameter settings take a common shape with a dimple at the center and bulge near the contact line. An empirical formula for the critical capillary number for sessile drops with 45° contact angle is derived for typical ranges of jet Reynolds number and relative drop sizes especially pertinent to Aerosol {Jet^{circledR}} printing.

  17. Corporate Jet

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Gulfstream Aerospace Corporation, Savannah, GA, used a version of a NASA program called WIBCO to design a wing for the Gulfstream IV (G-IV) which will help to reduce transonic drag (created by shock waves that develop as an airplane approaches the speed of sound). The G-IV cruises at 88 percent of the speed of sound, and holds the international record in its class for round-the-world flight. They also used the STANS5 and Profile programs in the design. They will use the NASA program GASP to help determine the gross weight, range, speed, payload and optimum wing area of an intercontinental supersonic business jet being developed in cooperation with Sukhoi Design Bureau, a Soviet organization.

  18. Jet fuels from synthetic crudes

    NASA Technical Reports Server (NTRS)

    Antoine, A. C.; Gallagher, J. P.

    1977-01-01

    An investigation was conducted to determine the technical problems in the conversion of a significant portion of a barrel of either a shale oil or a coal synthetic crude oil into a suitable aviation turbine fuel. Three syncrudes were used, one from shale and two from coal, chosen as representative of typical crudes from future commercial production. The material was used to produce jet fuels of varying specifications by distillation, hydrotreating, and hydrocracking. Attention is given to process requirements, hydrotreating process conditions, the methods used to analyze the final products, the conditions for shale oil processing, and the coal liquid processing conditions. The results of the investigation show that jet fuels of defined specifications can be made from oil shale and coal syncrudes using readily available commercial processes.

  19. Mass transfer during drop formation under jetting conditions

    Microsoft Academic Search

    Y. F. Huang

    1976-01-01

    An experimental study was made of the disperse phase controlled mass transfer during drop formation under jetting conditions. Liquid-liquid extraction in a perforated plate column was studied. The experimental technique of Skelland and Minhas was used but with a single nozzle. Three high interfacial tension systems and one low interfacial tension system were employed. The selection of these systems gave

  20. Risk factors of jet fuel combustion products.

    PubMed

    Tesseraux, Irene

    2004-04-01

    Air travel is increasing and airports are being newly built or enlarged. Concern is rising about the exposure to toxic combustion products in the population living in the vicinity of large airports. Jet fuels are well characterized regarding their physical and chemical properties. Health effects of fuel vapors and liquid fuel are described after occupational exposure and in animal studies. Rather less is known about combustion products of jet fuels and exposure to those. Aircraft emissions vary with the engine type, the engine load and the fuel. Among jet aircrafts there are differences between civil and military jet engines and their fuels. Combustion of jet fuel results in CO2, H2O, CO, C, NOx, particles and a great number of organic compounds. Among the emitted hydrocarbons (HCs), no compound (indicator) characteristic for jet engines could be detected so far. Jet engines do not seem to be a source of halogenated compounds or heavy metals. They contain, however, various toxicologically relevant compounds including carcinogenic substances. A comparison between organic compounds in the emissions of jet engines and diesel vehicle engines revealed no major differences in the composition. Risk factors of jet engine fuel exhaust can only be named in context of exposure data. Using available monitoring data, the possibilities and limitations for a risk assessment approach for the population living around large airports are presented. The analysis of such data shows that there is an impact on the air quality of the adjacent communities, but this impact does not result in levels higher than those in a typical urban environment. PMID:15093276

  1. Catalytic autothermal reforming of Jet fuel

    NASA Astrophysics Data System (ADS)

    Lenz, Bettina; Aicher, Thomas

    Aircraft manufacturers have to reduce the emissions and the specific fuel consumption of their systems. Fuel cell use in a 'more electric aircraft' can be one possibility. To keep the technology simple only one fuel (Jet A, Jet A-1) shall be used on board the aircraft. Therefore, the catalytic reforming of Jet A-1 fuel was examined in this paper, although the use of fossil fuels causes the production of greenhouse effect promoting gases like carbon dioxide CO 2. The autothermal reforming of desulphurised kerosene is examined with a 15 kW (based on the lower heating value of Jet fuel) test rig. The experiments are performed at steam to carbon ratios of S/C = 1.5-2.5 and air to fuel ratios of ? = 0.24-0.32, respectively. The composition of the product gas, the volumetric flow rate of the product gas at standard conditions and the temperatures in the catalyst are determined as a function of the operating variables. The gas hourly space velocity (GHSV) is varied between 50,000 and 300,000 h -1. The influence of sulphur containing feed streams (real Jet fuel) on reforming behaviour is investigated as well as the influence of the hydrogen concentration on the hydrodesulphurisation process. Another simple way of desulphurisation is the adsorption of liquid sulphur containing hydrocarbons, the influence of the variation of the liquid hourly space velocity (LHSV) is measured at a temperature of 150 °C.

  2. Radiation Resistances of Dielectric Liquids

    NASA Technical Reports Server (NTRS)

    Bouquet, Frank L.; Somoano, Robert B.

    1987-01-01

    Report presents data on effects of ionizing radiation on dielectric liquids for high-energy-density, pulsed-power capacitors. Based on Jet Propulsion Laboratory test results, search of NASA and Department of Energy computer files, survey of open literature, and contacts with manufacturers and suppliers. Covers 22 organic liquids, although detailed data found for only one compound, polydimethyl siloxane. Generic data on effects of radiation on compounds with similar chemical structures provided where data on specific compounds lacking.

  3. Partitioning of Aromatic Constituents into Water from Jet Fuels.

    PubMed

    Tien, Chien-Jung; Shu, Youn-Yuen; Ciou, Shih-Rong; Chen, Colin S

    2015-08-01

    A comprehensive study of the most commonly used jet fuels (i.e., Jet A-1 and JP-8) was performed to properly assess potential contamination of the subsurface environment from a leaking underground storage tank occurred in an airport. The objectives of this study were to evaluate the concentration ranges of the major components in the water-soluble fraction of jet fuels and to estimate the jet fuel-water partition coefficients (K fw) for target compounds using partitioning experiments and a polyparameter linear free-energy relationship (PP-LFER) approach. The average molecular weight of Jet A-1 and JP-8 was estimated to be 161 and 147 g/mole, respectively. The density of Jet A-1 and JP-8 was measured to be 786 and 780 g/L, respectively. The distribution of nonpolar target compounds between the fuel and water phases was described using a two-phase liquid-liquid equilibrium model. Models were derived using Raoult's law convention for the activity coefficients and the liquid solubility. The observed inverse, log-log linear dependence of the K fw values on the aqueous solubility were well predicted by assuming jet fuel to be an ideal solvent mixture. The experimental partition coefficients were generally well reproduced by PP-LFER. PMID:25840956

  4. Transient behavior of superheated water jets boiling

    NASA Astrophysics Data System (ADS)

    Reshetnikov, A. V.; Busov, K. A.; Mazheiko, N. A.; Skokov, V. N.; Koverda, V. P.

    2012-06-01

    Superheated water flowing out from high-pressure chamber through short cylindrical and slot channel has been studied experimentally. Relation of vaporization mechanisms in superheated liquid (boiling in single, not interacting centers, intense heterogeneous vaporization, and homogeneous fluctuating nucleation) and respective forms of superheated water jets has been determined. Temperature intervals with transient behavior of boiling have been determined. It is shown that at transient behavior of boiling the amplitude of pulsations of jet parameters increases, and in the spectra of pulsation power, the low-frequency component 1/ f appears.

  5. Effect of freezing temperature, at which straws were plunged into liquid nitrogen, on the post-thaw motility and acrosomal status of ram spermatozoa.

    PubMed

    Bag, Sadhan; Joshi, Anil; Naqvi, S M K; Rawat, P S; Mittal, J P

    2002-08-15

    The present study was conducted to observe the effect of initial freezing temperature on subsequent survival and acrosomal integrity of Malpura and Bharat Merino ram spermatozoa during post-thawing incubation. Semen samples were diluted in TEST-yolk-glycerol extender, loaded in 0.25 ml straws and cooled down to -25, -75 or -125 degrees C freezing temperature using a programmable cell freezer. Computer assisted sperm analysis and acrosomal integrity of thawed samples were assessed after thawing and at hourly intervals during incubation at 37 degrees C for 4 h. The percentage of motile cells in samples frozen at -125 degrees C were 80.3 and 63.7 after post-thawing and -thawing incubation, compared to 75.9 and 39.7 at -25 degrees C or 73.9 and 51.8 at -75 degrees C temperatures, respectively. The spermatozoa with normal acrosome were also significantly, respectively, higher in samples frozen at -125 degrees C, compared to -25 and -75 degrees C temperatures. There were no significant breed variations on percentage of motile, percentage of rapidly motile cells, percentage of normal acrosomes, curvilinear velocity and lateral head displacement except straight line velocity and average path velocity of spermatozoa. The results indicated that -125 degrees C initial freezing temperature conferred the best cryopreserving ability to ram spermatozoa for post-thawing thermoresistance test compared to -25 or -75 degrees C freezing temperature. PMID:12137980

  6. Control of jet noise

    NASA Technical Reports Server (NTRS)

    Schreck, Stefan

    1993-01-01

    This reports describes experiments conducted at the High-Speed Jet Facility at the University of Southern California on supersonic jets. The goal of the study was to develop methods for controlling the noise emitted from supersonic jets by passive and/or active means. Work by Seiner et al (1991) indicates that eddy Mach wave radiation is the dominant noise source in a heated high speed jet. Eddy Mach radiation is caused by turbulent eddies traveling at supersonic speed in the shear layer of the jet. The convection velocity of the eddies decays with increasing distance from the nozzle exit due to the mixing of the jet stream with the ambient fluid. Once the convection speed reaches subsonic velocities, eddy Mach wave radiation ceases. To control noise, a rapid decay of the convection velocity is desired. This may be accomplished by enhanced mixing in the jet. In this study, small aspect ratio rectangular jet nozzles were tested. A flapping mode was noticed in the jets. By amplifying screech components of the jets and destabilizing the jet columns with a collar device, the flapping mode was excited. The result was a rapid decay of the jet velocity. A reduction in eddy Mach radiation in rectangular supersonic jets may be achieved with this device.

  7. Two-fluid jets and wakes

    NASA Astrophysics Data System (ADS)

    Herczynski, Andrzej; Weidman, Patrick D.; Burde, Georgy I.

    2004-04-01

    Similarity solutions for laminar two-fluid jets and wakes are derived in the boundary-layer approximation. Planar and axisymmetric fan jets as well as classical and momentumless planar wakes are considered. The interface between the immiscible fluids is stabilized by the action of gravity, with the heavier fluid, taken to be a liquid, placed beneath the lighter fluid. Velocity profiles for the jets and the classical wake depend intimately, but differently, on the parameter ?=?1?1/?2?2, where ?i and ?i are, respectively, the density and absolute viscosity of the fluid in the upper (i=1) and lower (i=2) fluid domains, while the momentumless wake profile depends on the parameter ?=?1?23/?2?13. Generally, all interfaces deflect from horizontal except the fan jet. However, while the interface for the classical planar two-fluid wake is never flat, the interfaces for the planar jet and the momentumless wake become flat in the particular case ?1=?2. Velocity profiles illustrating the strongly asymmetrical jet and wake profiles that arise in air-over-water, oil-over-water, and air-over-oil flows are presented.

  8. Jet formation from impulsive cavity collapse

    NASA Astrophysics Data System (ADS)

    Antkowiak, Arnaud; Bremond, Nicolas; Le Dizés, Stéphane; Villermaux, Emmanuel

    2006-11-01

    A cavity at a free liquid/gas interface collapsing due to an impulsive body force forms an intense concentrated jet. This is the paradigm for bubbles bursting at a liquid surface, the collapse of cavitation bubbles near a rigid boundary, collapsing voids following an impact, shaped charges, gravity waves colliding a dam, high amplitude Faraday waves, to quote a few examples among many. We address this problem by considering the axial impact of a cylindrical tube falling by gravity and filled with a liquid wetting the tube wall. Following the impact on a rigid floor, the curvature of the spherical meniscus initially fixed by the tube radius reverses violently, prelude of the birth of a rapid ascending jet. We derive the initial velocity and pressure field around the cavity just after the impact from Euler equations. They are insensitive to liquid viscosity and surface tension, consistently with detailed PIV measurements from high speed movies of the phenomenon. The extension to a cavity no more confined by rigid walls, the dynamics of the resulting jet and its final fragmentation will be considered as well.

  9. The Transition from Inspiral to Plunge for a Compact Body in a Circular Equatorial Orbit Around a Massive, Spinning Black Hole

    E-print Network

    Amos Ori; Kip S. Thorne

    2000-03-08

    There are three regimes of gravitational-radiation-reaction-induced inspiral for a compact body with mass mu, in a circular, equatorial orbit around a Kerr black hole with mass M>>mu: (i) The "adiabatic inspiral regime", in which the body gradually descends through a sequence of circular, geodesic orbits. (ii) A "transition regime", near the innermost stable circular orbit (isco). (iii) The "plunge regime", in which the body travels on a geodesic from slightly below the isco into the hole's horizon. This paper gives an analytic treatment of the transition regime and shows that, with some luck, gravitational waves from the transition might be measurable by the space-based LISA mission.

  10. Confined radial buoyant jet

    SciTech Connect

    Fry, D.J.; Adams, E.

    1983-09-01

    A submerged, negatively buoyant radial jet, discharging horizontally beneath a free surface into water of initially uniform density, was studied experimentally and theoretically. The situation relates to the operation of an ocean thermal energy conversion plant and is an example of buoyancy and confinement offering opposing influences on jet trajectory. For shallow submergence, the jet is attached to the free surface while for large submergence or greater (negative) buoyancy, the jet is detached. An experimental program yielded data on jet trajectory, temperature, velocity and discharge conditions associated with transition between attached and detached regimes. A hysteresis effect was noted as the conditions for attachment and detachment were different. Dimensional analysis yielded a single parameter of primary importance and two parameters of secondary importance in describing jet behavior. An integral jet analysis based on a spreading assumption was successfully adapted to include induced velocity and pressure effects on jet behavior.

  11. Theory of Relativistic Jets

    NASA Astrophysics Data System (ADS)

    Vlahakis, Nektarios

    Relativistic jets can be modeled as magnetohydrodynamic flows. We analyze the related equations and discuss the involved acceleration mechanisms, their relation to the collimation, to the jet confinement by its environment, and to possible rarefaction waves triggered by pressure imbalances.

  12. Fluid jet electric discharge source

    DOEpatents

    Bender, Howard A. (Ripon, CA)

    2006-04-25

    A fluid jet or filament source and a pair of coaxial high voltage electrodes, in combination, comprise an electrical discharge system to produce radiation and, in particular, EUV radiation. The fluid jet source is composed of at least two serially connected reservoirs, a first reservoir into which a fluid, that can be either a liquid or a gas, can be fed at some pressure higher than atmospheric and a second reservoir maintained at a lower pressure than the first. The fluid is allowed to expand through an aperture into a high vacuum region between a pair of coaxial electrodes. This second expansion produces a narrow well-directed fluid jet whose size is dependent on the size and configuration of the apertures and the pressure used in the reservoir. At some time during the flow of the fluid filament, a high voltage pulse is applied to the electrodes to excite the fluid to form a plasma which provides the desired radiation; the wavelength of the radiation being determined by the composition of the fluid.

  13. NASA Jet Noise Research

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda

    2012-01-01

    The presentation highlights jet-noise research conducted in the Subsonic Fixed Wing, Supersonics, and Environmentally Responsible Aviation Projects in the Fundamental Aeronautics Program at NASA. The research efforts discussed include NASA's updated Aircraft NOise Prediction Program (ANOPP2), acoustic-analogy-based prediction tools, jet-surface-interaction studies, plasma-actuator investigations, N+2 Supersonics Validation studies, rectangular-jet experiments, twin-jet experiments, and Hybrid Wind Body (HWB) activities.

  14. Jet physics in ALICE

    Microsoft Academic Search

    Constantinos A. Loizides; Johann Wolfgang von Goethe

    2005-01-01

    This work aims at the performance of the ALICE detector for the measurement of high-energy jets at mid-pseudo-rapidity in ultra-relativistic nucleus--nucleus collisions at LHC and their potential for the characterization of the partonic matter created in these collisions. In our approach, jets at high energy with E_{T}>50 GeV are reconstructed with a cone jet finder, as typically done for jet

  15. Jets at all scales

    E-print Network

    F. Tavecchio

    2002-12-11

    I discuss recent developments in the field of relativistic jets in AGNs. After a brief review of our current knowledge of emission from Blazars, I discuss some consequences of the recent detection made by {\\it Chandra} of X-ray emission from extended jets. Finally I report some recent results on the problem of the connection between accretion and jets, study that in principle could shed light on the important issue of jet formation.

  16. On vortex generating jets

    Microsoft Academic Search

    Zia U. Khan; James P. Johnston

    2000-01-01

    Vortex generating jets (VGJs) are jets that pass through a wall and into a crossflow to create a dominant streamwise vortex that remains embedded in the boundary layer over the wall. The VGJ is characterized by its pitch and skew angles (? and ?) and the velocity ratio (VR) between the jet and the crossflow. For VR=1.0, the VGJ configuration

  17. Numerical simulation of operation processes in the combustion chamber and gas generator of oxygen-methane liquid rocket engine

    NASA Astrophysics Data System (ADS)

    Kalmykov, G. P.; Larionov, A. A.; Sidlerov, D. A.; Yanchilin, L. A.

    2009-09-01

    The results of numerical simulations of processes in gas generators and combustion chambers operating on oxygen and methane are presented. Specific features of mixing, evaporation, and combustion of propellants have been investigated. The degree of combustion completeness in chambers with three types of injectors - coaxial-jet gas-liquid, liquid-liquid monopropellant, and bipropellant impinging-jets injectors - has been estimated.

  18. Supersonic air flow due to solid-liquid impact.

    PubMed

    Gekle, Stephan; Peters, Ivo R; Gordillo, José Manuel; van der Meer, Devaraj; Lohse, Detlef

    2010-01-15

    A solid object impacting on liquid creates a liquid jet due to the collapse of the impact cavity. Using visualization experiments with smoke particles and multiscale simulations, we show that in addition, a high-speed air jet is pushed out of the cavity. Despite an impact velocity of only 1 m/s, this air jet attains supersonic speeds already when the cavity is slightly larger than 1 mm in diameter. The structure of the air flow closely resembles that of compressible flow through a nozzle-with the key difference that here the "nozzle" is a liquid cavity shrinking rapidly in time. PMID:20366598

  19. Cavitating vortex generation by a submerged jet

    SciTech Connect

    Belyakov, G. V. [Russian Academy of Sciences, Institute for Dynamics of Geospheres (Russian Federation); Filippov, A. N. [Moscow State University of Food Production (Russian Federation)], E-mail: a.filippov@mgupp.ru

    2006-05-15

    The surface geometry of a cavitating vortex is determined in the limit of inviscid incompressible flow. The limit surface is an ovaloid of revolution with an axis ratio of 5: 3. It is shown that a cavitating vortex ring cannot develop if the cavitation number is lower than a certain critical value. Experiments conducted at various liquid pressures and several jet exit velocities confirm the existence of a critical cavitation number close to 3. At cavitation numbers higher than the critical one, the cavitating vortex ring does not develop. At substantially lower cavitation numbers (k {<=} 0.1), an elongated asymmetric cavitation bubble is generated, with an axial reentrant jet whose length can exceed the initial jet length by several times. This flow structure is called an asymmetric cavitating vortex, even though steady motion of this structure has not been observed.

  20. Jet pump assisted arterial heat pipe

    NASA Technical Reports Server (NTRS)

    Bienert, W. B.; Ducao, A. S.; Trimmer, D. S.

    1978-01-01

    This paper discusses the concept of an arterial heat pipe with a capillary driven jet pump. The jet pump generates a suction which pumps vapor and noncondensible gas from the artery. The suction also forces liquid into the artery and maintains it in a primed condition. A theoretical model was developed which predicts the existence of two stable ranges. Up to a certain tilt the artery will prime by itself once a heat load is applied to the heat pipe. At higher tilts, the jet pump can maintain the artery in a primed condition but self-priming is not possible. A prototype heat pipe was tested which self-primed up to a tilt of 1.9 cm, with a heat load of 500 watts. The heat pipe continued to prime reliably when operated as a VCHP, i.e., after a large amount of noncondensible gas was introduced.

  1. On the Evolution of Vorticity in Pulsating Jets in Crossflow

    NASA Astrophysics Data System (ADS)

    Cortelezzi, Luca; Karagozian, Ann R.

    1999-11-01

    Significant alteration of the mixing characteristics of jets in crossflow may be achieved when the jet is pulsed in the case of liquids(Johari, et al., AIAA J., 37:7, pp. 2195-2203, 1999) or acoustically driven in the case of gases(Kelso, et al., JFM, 306, pp. 111-144, 1996). The three-dimensional vortex element simulations performed here focus on exploring the vorticity evolution associated with such jets and the role of vorticity in producing experimentally observed increases in jet spreading and penetration during excitation. Alternative modes of temporal jet excitation are examined, including sinusoidal and square wave variation in jet velocity for a variety of input frequencies, amplitudes, and duty cycles. It is seen that these jet forcing parameters control vortex bending, tilting, and reconnection which in turn are responsible for the overall jet structure as well as enhanced jet mixing and penetration.

  2. Refrigerated hydrogen gas jet for the Fermilab antiproton accumulator

    SciTech Connect

    Allspach, D.H.; Kendziora, C.L. [Fermi National Accelerator Lab., Batavia, IL (United States); Marinelli, M. [Univ. of Genoa (Italy). Dept. of Physics] [and others

    1995-07-01

    A hydrogen gas jet has been built for use at Fermilab for the study of charmonium spectroscopy in proton-antiproton annihilations. The hydrogen gas jet is part of an upgrade to a previous experiment which ran in the Fermilab 1990-1991 fixed target program utilizing a jet cooled to 80 K with liquid nitrogen. The jet delivers a defined stream of hydrogen gas which travels through a series of vacuum chambers and then intersects the circulating antiproton beam. The goal of the upgrade is to provide a hydrogen gas stream at least twice as dense as used for the earlier experiment to increase the interaction rate and allow an improved study of rare processes. This is achieved by cooling the stream to below 30 K using a Gifford-McMahon refrigerator. The jet apparatus is designed to allow motion in the plane perpendicular to the gas stream as well as angular positioning at the jet nozzle to provide a means of optimizing the interaction rate. Two skimmers located in the vacuum chambers are used to define the gas stream dimensions. The jet target vacuum chambers require constant pumping with turbomolecular pumps. The vacuum space around the jet is designed to have a large system pumping speed so that the chamber pressure can be maintained below an absolute pressure of 1 Pa. The jet will operate in the next fixed target run at Fermilab. Details of the design and test results are discussed.

  3. Modeling atomization of a round water jet by a high-speed annular air jet based on the self-similarity of droplet breakup

    Microsoft Academic Search

    De-Jun Jiang; Hai-Feng Liu; Wei-Feng Li; Jian-Liang Xu; Fu-Chen Wang; Xin Gong

    Based on the self-similarity of droplet breakup in the secondary atomization region, the atomization process of coaxial air-blast atomizer has been investigated. The relationship of Sauter mean diameter (SMD) with the effects of gas jet velocity, liquid jet velocity and diameter and liquid\\/gas mass flux ratio was obtained according to the breakup time and motion characteristic of droplet in air

  4. Steam-water jet analysis. Final report

    SciTech Connect

    Kashiwa, B.A.; Harlow, F.H.; Demuth, R.B.; Ruppel, H.M.

    1984-05-01

    This report presents the results of a theoretical study on the effects of the steam-water jet emitted from a hypothetical rupture in the high-pressure piping pf a nuclear power plant. A set of calculations is presented, incorporating increasingly complex formulations for mass and momentum exchange between the liquid and vapor flow fields. Comparisons between theory and detailed experimental data are given. The study begins with a thorough evaluation of the specification of equilibrium mass and momentum exchange (homogeneous equilibrium) throughout the flow region, a model that generally overpredicts the rate of jet momentum divergence. The study finds that a near-equilibrium momentum exchange rate and a strongly nonequilibrium momentum exchange rate are needed in the region of large vapor-volume fraction to explain the impingement data for fully developed two-phase jets. This leads to the viewpoint that the large-scale jet is characterized by a flow of large liquid entities that travel relatively unaffected by the strongly diverging vapor flow field. The study also finds circumstances in which a persistent core of metastable superheated water can cause much larger impingement pressures than would otherwise be possible. Existing engineering methods are evaluated for jet-loading predictions in plant design. The existing methods appear to be conservative in most possible rupture circumstances with one exception: when the impingement target is about one pipe-diameter away, large enough to capture the full jet, and the rupture flow area is equal to the full pipe flow area, the existing method can produce loadings that are slightly lower than observed for subcooled, flashing discharge. Recommendations have been made to improve the prediction of existing methods under these conditions.

  5. Jetting instability mechanisms of particles from explosive dispersal

    NASA Astrophysics Data System (ADS)

    Ripley, R. C.; Zhang, F.

    2014-05-01

    The formation of post-detonation 'particle' jets is widely observed in many problems associated with explosive dispersal of granular materials and liquids. Jets have been shown to form very early, however the mechanism controlling the number of jetting instabilities remains unresolved despite a number of active theories. Recent experiments involving cylindrical charges with a range of central explosive masses for dispersal of dry solid particles and pure liquid are used to formulate macroscopic numerical models for jet formation and growth. The number of jets is strongly related to the dominant perturbation during the shock interaction timescale that controls the initial fracturing of the particle bed and liquid bulk. Perturbations may originate at the interfaces between explosive, shock-dispersed media, and outer edge of the charge due to Richtmyer-Meshkov instabilities. The inner boundary controls the number of major structures, while the outer boundary may introduce additional overlapping structures and microjets that are overtaken by the major structures. In practice, each interface may feature a thin casing material that breaks up, thereby influencing or possibly dominating the instabilities. Hydrocode simulation is used to examine the role of each interface in conjunction with casing effects on the perturbation leading to jet initiation. The subsequent formation of coherent jet structures requires dense multiphase flow of particles and droplets that interact though inelastic collision, agglomeration, and turbulent flow. Macroscopic multiphase flow simulation shows dense particle clustering and major jet structures overtaking smaller instabilities. Late-time dispersal is controlled by particle drag and evaporation of droplets. Numerical results for dispersal and jetting evolution are compared with experiments.

  6. Aeroacoustics of hot jets

    NASA Astrophysics Data System (ADS)

    Viswanathan, K.

    2004-10-01

    A systematic study has been undertaken to quantify the effect of jet temperature on the noise radiated by subsonic jets. Nozzles of different diameters were tested to uncover the effects of Reynolds number. All the tests were carried out at Boeing's Low Speed Aeroacoustic Facility, with simultaneous measurement of thrust and noise. It is concluded that the change in spectral shape at high jet temperatures, normally attributed to the contribution from dipoles, is due to Reynolds number effects and not dipoles. This effect has not been identified before. A critical value of the Reynolds number that would need to be maintained to avoid the effects associated with low Reynolds number has been estimated to be {˜}400 000. It is well-known that large-scale structures are the dominant generators of noise in the peak radiation direction for high-speed jets. Experimental evidence is presented that shows the spectral shape at angles close to the jet axis from unheated low subsonic jets to be the same as from heated supersonic jets. A possible mechanism for the observed trend is proposed. When a subsonic jet is heated with the Mach number held constant, there is a broadening of the angular sector in which peak radiation occurs. Furthermore, there is a broadening of the spectral peak. Similar trends have been observed at supersonic Mach numbers. The spectral shapes in the forward quadrant and in the near-normal angles from unheated and heated subsonic jets also conform to the universal shape obtained from supersonic jet data. Just as for unheated jets, the peak frequency at angles close to the jet axis is independent of jet velocity as long as the acoustic Mach number is less than unity. The extensive database generated in the current test programme is intended to provide test cases with high-quality data that could be used for the evaluation of theoretical/semi-theoretical jet noise prediction methodologies.

  7. Interaction between jets during laser-induced forward transfer

    SciTech Connect

    Patrascioiu, A.; Florian, C.; Fernández-Pradas, J. M.; Morenza, J. L.; Serra, P., E-mail: pserra@ub.edu [Departament de Física Aplicada i Òptica, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona (Spain); Hennig, G. [DI Projekt AG, Flugplatz, CH-3368 Bleienbach (Switzerland); Delaporte, P. [Aix Marseille University, CNRS, LP3 UMR 7341, 163 Avenue de Luminy, 13288 Marseille (France)

    2014-07-07

    Simultaneous two-beam laser-induced forward transfer (LIFT) was carried out for various inter-beam separations, analyzing both the resulting printing outcomes and the corresponding liquid transfer dynamics. In a first experiment, droplets of an aqueous solution were printed onto a substrate at different inter-beam distances, which proved that a significant departure from the single-beam LIFT dynamics takes places at specific separations. In the second experiment, time-resolved imaging analysis revealed the existence of significant jet-jet interactions at those separations; such interactions proceed through a dynamics that results in remarkable jet deflection for which a possible onset mechanism is proposed.

  8. Interaction of a free jet with a perpendicular control jet

    Microsoft Academic Search

    David A. Tamburello; Michael Amitay

    2007-01-01

    The effects of the upstream location of a single continuous control jet (i.e., within the main jet nozzle) on an axisymmetric free jet, at Reynolds numbers of 6600 and 26 500, were investigated experimentally using PIV. The control jet was oriented perpendicular to the main jet flow and its momentum coefficient was varied for each Reynolds number. The resultant mean

  9. Concentration Distributions during Pulse Jet Mixing

    SciTech Connect

    Bamberger, Judith A.; Meyer, Perry A.

    2010-08-05

    Obtaining real-time, in situ slurry concentration measurements during unsteady mixing can provide increased understanding into mixer performance. During recent tests an ultrasonic attenuation sensor was inserted into a mixing vessel to measure the slurry concentration during unsteady mixing in real time during pulse jet mixer operation. These pulse jet mixing tests to suspend noncohesive solids in Newtonian liquid were conducted at three geometric scales. To understand the solids suspension process and resulting solids distribution, the concentration of solids in the cloud was measured at various elevations and radial positions during the pulse jet mixer cycle. In the largest scale vessel, concentration profiles were measured at three radial locations: r = 0, 0.5 and 0.9 R where R is the vessel radius. These radial concentration data are being analyzed to provide a model for predicting concentration as a function of elevation. This paper describes pulse jet mixer operation, provides a description of the concentration probe, and presents transient concentration data obtained at three radial positions: in the vessel center (O R), midway between the center and the wall (0.5 R) and near the vessel wall (0.9 R) through out the pulse to provide insight into pulse jet mixer performance.

  10. Microquasar jets: A comparison with extragalactic jets

    NASA Astrophysics Data System (ADS)

    Spencer, R.; de La Force, C.; Stirling, A.

    2001-01-01

    Several radio jets associated with X-ray binary stars or soft X-ray transients in our galaxy have been discovered in recent years. In some cases apparent superluminal motion of features in the jets has been found, leading to the objects being called microquasars. There are many similarities with the more distant extragalactic objects not the least of which is the belief that nearly all of the objects are black-hole candidates. Both types of jets are produced via processes in the inner part of an accretion disk surrounding the black-hole, which may also extract spin energy from the black-hole. We may expect to see similar properties of the jets in quasars and microquasars (though on very different size scales) if the production mechanisms are similar. In this paper we compare the structure and physical properties of microquasar jets with those typically found in radio loud galaxies and quasars, with the aim of finding similarities and differences which may shed light on the jet production process.

  11. Experimental study of underwater rock drilling using a pulsed Ho:YAG laser-induced jets

    Microsoft Academic Search

    K. Ohtani; D. Numata; K. Takayama; T. Kobayashi; K. Okatsu

    2009-01-01

    This paper is primarily an assessment of laser-induced water jets for boring rock surfaces. It also reports the result of\\u000a preliminary experiments of pulsed Ho:YAG laser-induced jets applied to drill a submerged rock specimen. The irradiation of\\u000a pulsed Ho:YAG laser beams at 3 Hz inside a thin metal tube produces intermittent water vapor bubbles which result in liquid\\u000a jet discharge from

  12. Stabilization of liquified-inert-gas jets for laser-plasma generation

    Microsoft Academic Search

    B. A. M. Hansson; M. Berglund; O. Hemberg; H. M. Hertz

    2004-01-01

    We investigate the hydrodynamic properties of liquified-inert-gas jets in a vacuum with a special emphasis on their stability. Such jets have applications as targets for laser-plasma generation of soft-x-ray and extreme-ultraviolet (EUV) radiation. An important example is the liquid-xenon-jet laser-plasma source, one of the source candidates for EUV lithography. A simple hydrodynamic model in not sufficient to explain experimental observations

  13. Stabilization of liquified-inert-gas jets for laser–plasma generation

    Microsoft Academic Search

    B. A. M. Hansson; M. Berglund; O. Hemberg; H. M. Hertz

    2004-01-01

    We investigate the hydrodynamic properties of liquified-inert-gas jets in a vacuum with a special emphasis on their stability. Such jets have applications as targets for laser–plasma generation of soft-x-ray and extreme-ultraviolet (EUV) radiation. An important example is the liquid-xenon-jet laser-plasma source, one of the source candidates for EUV lithography. A simple hydrodynamic model in not sufficient to explain experimental observations

  14. Instabilities of jets of non-Newtonian fluids impacting a plate

    E-print Network

    Varagnat, Matthieu

    2008-01-01

    The problem of buckling and coiling of jets of viscous, Newtonian liquids impacting a plate has received a substantial level of attention over the past two decades, both from experimental and theoretical points of view. ...

  15. Combustion Characteristics of Pressurized Swirling Spray Flame and Unsteady Two-Phase Exhaust Jet

    Microsoft Academic Search

    Martin B. Linck; Ashwani K. Gupta; Guillaume Bourhis; Ken Yu

    The effects of flame enclosure and combustor pressure on the combustor flowfield and structure of turbulent spray flames have been investigated. The exhaust jet from the combustor was directed into water to simulate underwater propulsion applications. Two- phase interactions between the exhaust jet from the pressurized combustor and liquid water in an attached mixing chamber have been examined to address

  16. A simple model for nanofiber formation by rotary jet-spinning Paula Mellado,1,2

    E-print Network

    Parker, Kevin Kit

    a liquid, polymeric jet out of the reservoir orifice that stretches, dries, and eventually solidifies- chanical flexibility, and directional strength make nanofibers an ideal platform for a diverse range, the remaining solvent evaporates, fibers solidify, and may be collected. To quantify the dynamics of jet

  17. Comparison of Inconel 625 and Inconel 600 in resistance to cavitation erosion and jet impingement erosion

    Microsoft Academic Search

    H. X. Hu; Y. G. Zheng; C. P. Qin

    2010-01-01

    Liquid droplet erosion (LDE), which often occurs in bellows made of nickel-based alloys, threatens the security operation of the nuclear power plant. As the candidate materials of the bellows, Inconel 600 and Inconel 625 were both tested for resistance to cavitation erosion (CE) and jet impingement erosion (JIE) through vibratory cavitation equipment and a jet apparatus for erosion-corrosion. Cumulative mass

  18. The Deformation of Solids by Liquid Impact at Supersonic Speeds

    Microsoft Academic Search

    F. P. Bowden; J. H. Brunton

    1961-01-01

    A study has been made of the deformation of solids at high rates of strain which are produced by the impact of a small cylinder or jet of liquid on the surface of the solid. A method is developed for projecting this jet against the solid at velocities up to 1200 m\\/s. The subsequent deformation of the solid under impact

  19. Fermi liquids and Luttinger liquids

    Microsoft Academic Search

    H. J. Schulz; G. Cuniberti; P. Pieri

    1998-01-01

    In these lecture notes, the basic physics of Fermi liquids and Luttinger liquids is presented. Fermi liquids are discussed both from a phenomenological viewpoint, in relation to microscopic approaches, and as renormalization group fixed points. Luttinger liquids are introduced using the bosonization formalism, and their essential differences with Fermi liquids are pointed out. Applications to transport effects, the effect of

  20. Strategic Technology JET PROPULSION LABORATORY

    E-print Network

    Waliser, Duane E.

    Strategic Technology Directions JET PROPULSION LABORATORY National Aeronautics and Space, and science goals for NASA and the Jet Propulsion Laboratory. It derives from and updates the previous also represent technology capabilities that the Jet Propulsion Laboratory believes are essential

  1. Experimental Study on Thermal Interaction of Ethanol Jets in High Temperature Fluorinert

    NASA Astrophysics Data System (ADS)

    Sa, Rongyuan; Takahashi, Minoru

    As a fundamental study for the direct contact heat exchange which was employed for in-vessel heat exchange in the Pb-Bi-cooled direct contact boiling water small fast reactor (PBWFR) and for the steam generator tube rupture (SGTR) accident in lead alloy-cooled fast reactor (LFR), ethanol jet was injected into high temperature fluorinert (FC-3283) as a simulation experiment in order to investigate the jet boiling phenomena just after volatile water contacting with the high temperature continuous lead alloy liquid. Two series of tests (no-boiling and boiling) were initiated to evaluate the ethanol vapor volume which generated around the ethanol jet. From synchronized temperature measurement around ethanol jet, the overview of the boiling behavior showed that jet boiling occurred at bottom part of jet first and developed to the upper part within very narrow area around jet.

  2. Two-valued breakup length of a water jet issuing from a finite-length nozzle under normal gravity.

    PubMed

    Umemura, Akira; Kawanabe, Sho; Suzuki, Sousuke; Osaka, Jun

    2011-09-01

    Laboratory experiments are conducted in which water is issued vertically downward from a finite-length nozzle at a constant speed using a piston. The results of these experiments indicate that the breakup length of the liquid jet is two-valued at Weber numbers greater than unity but less than a certain value, which depends on the nozzle length-to-radius ratio and the Bond number. In addition to a long breakup length, which is consistent with the conventional observation, another shorter breakup length is realized at the same jet issue speed. Each experimental run for a specific jet issue speed begins from the start of liquid issue so that each run is independent of the other runs. Transition between the two breakup lengths seldom occurs in each run. Which of the two breakup lengths occurs is determined at the start of liquid issue, when the capillary wave produced by the liquid jet tip contraction easily reaches the nozzle exit. Unlike the conventional belief, which is based on the Plateau-Rayleigh instability theory, this experimental evidence demonstrates that liquid jet disintegration occurs in a deterministic manner. The previously proposed self-destabilizing mechanism of a liquid jet in microgravity, in which the origin of the unstable wave responsible for the breakups is attributed to the formation of an upstream propagating capillary wave at every breakup, is extended to explore the physics underlying the observed liquid jet disintegration behaviors. PMID:22060494

  3. Electrokinetic Power Generation from Liquid Water Microjets

    SciTech Connect

    Duffin, Andrew M.; Saykally, Richard J.

    2008-02-15

    Although electrokinetic effects are not new, only recently have they been investigated for possible use in energy conversion devices. We have recently reported the electrokinetic generation of molecular hydrogen from rapidly flowing liquid water microjets [Duffin et al. JPCC 2007, 111, 12031]. Here, we describe the use of liquid water microjets for direct conversion of electrokinetic energy to electrical power. Previous studies of electrokinetic power production have reported low efficiencies ({approx}3%), limited by back conduction of ions at the surface and in the bulk liquid. Liquid microjets eliminate energy dissipation due to back conduction and, measuring only at the jet target, yield conversion efficiencies exceeding 10%.

  4. Supersonic Jet Control

    NASA Astrophysics Data System (ADS)

    Samimy, Mo

    2004-11-01

    Supersonic jets could be controlled via various means, for example, by imparting streamwise vorticity into the jet or by exciting one of the jet instabilities. The jet control in the first category has been achieved mostly passively through the use of vortex generating tabs or chevrons. The primary mechanism in such a device is spanwise/azimuthal pressure gradient imposed by the device, which rolls up into streamwise vorticity. The jet control in the second category could be achieved via fluidic or plasma actuators. The most recent work from the author's laboratory on supersonic jet control will be presented. On the topic of using tabs, an additional mechanism is revealed via the use of advanced laser based diagnostics. It will be shown that plasma actuators could produce strong localized perturbations of various frequencies (DC to over 100 kHz) to excite jet column or jet initial shear layer instability. In addition, these actuators could be used to mimic the effects of tabs or chevrons in generating streamwise vorticity.

  5. Jets with Variable R

    SciTech Connect

    Krohn, David [Department of Physics, Princeton University, Princeton, NJ 08540 (United States)

    2010-02-10

    We introduce a new class of infrared/collinear-safe and boost-invariant jet algorithms designed to return jets of variable angular size. In particular, we discuss an instance of these algorithms useful in reconstructing a commonly encountered type of event.

  6. Fast quantitative determination of platinum in liquid samples by laser-induced breakdown spectroscopy.

    PubMed

    Barreda, Flory-Anne; Trichard, Florian; Barbier, Sophie; Gilon, Nicole; Saint-Jalmes, Laurent

    2012-07-01

    The potential of laser-induced breakdown spectroscopy (LIBS) for the rapid determination of platinum in liquid silicone oils has been evaluated in the framework of on-line process control. A comparison of LIBS sensitivity between three setups designed for liquid analysis (static, liquid jet and flowing liquid) was performed using a 266 nm Nd/YAG laser irradiation. Best results were obtained using the flowing liquid setup and a similar limit of detection was obtained using the liquid jet. The effect of different buffer gases (Ar, He, N(2), etc.) on the signal sensitivity was studied in liquid jet analysis and best values were obtained with a nitrogen sheath gas. Detection limits were in the 100 mg/kg range for both setups. Quantitative determination of platinum in real liquid samples was also investigated using both liquid jet and flowing liquid setups. Calibration curves were plotted for Pt with the liquid jet and the flowing liquid setups under optimised temporal acquisition parameters (delay time and gate width). A normalisation using a silicon line was applied and recovery ranged from 3 to 15% for Pt in catalyst samples with both setups showing that LIBS is a sensitive and accurate method for on-line applications. PMID:22547353

  7. Jet physics at CDF

    SciTech Connect

    Melese, P.

    1997-05-01

    We present high E{sub T} jet measurements from CDF at the Fermilab Tevatron Collider. The incfilusive jet cross section at {radical}s = 1800 GeV with {approximately} 5 times more data is compared to the published CDF results, preliminary D0 results, and next-to-leading order QCD predictions. The {summation}E{sub T} cross section is also compared to QCD predictions and the dijet angular distribution is used to place a limit on quark compositeness. The inclusive jet cross section at {radical}s = 630 GeV is compared with that at 1800 GeV to test the QCD predictions for the scaling of jet cross sections with {radical}s. Finally, we present momentum distributions of charged particles in jets and compare them to Modified Leading Log Approximation predictions.

  8. Instability of rectangular jets

    NASA Technical Reports Server (NTRS)

    Tam, Christopher K. W.; Thies, Andrew T.

    1992-01-01

    The instability of rectangular jets is investigated using a vortex sheet model. It is shown that such jets support four linearly independent families of instability waves. Within each family there are infinitely many modes. A way to classify these modes according to the characteristics of their mode shapes or eigenfunctions is proposed. A parametric study of the instability wave characteristics has been carried out. A sample of the numerical results is reported here. It is found that the first and third modes of each instability wave family are corner modes. The pressure fluctuations associated with these instability waves are localized near the corners of the jet. The second mode, however, is a center mode with maximum fluctuations concentrated in the central portion of the jet flow. The center mode has the largest spatial growth rate. It is anticipated that as the instability waves propagate downstream the center mode would emerge as the dominant instability of the jet.

  9. Description of Jet Breakup

    NASA Technical Reports Server (NTRS)

    Papageorgiou, Demetrios T.

    1996-01-01

    In this article we review recent results on the breakup of cylindrical jets of a Newtonian fluid. Capillary forces provide the main driving mechanism and our interest is in the description of the flow as the jet pinches to form drops. The approach is to describe such topological singularities by constructing local (in time and space) similarity solutions from the governing equations. This is described for breakup according to the Euler, Stokes or Navier-Stokes equations. It is found that slender jet theories can be applied when viscosity is present, but for inviscid jets the local shape of the jet at breakup is most likely of a non-slender geometry. Systems of one-dimensional models of the governing equations are solved numerically in order to illustrate these differences.

  10. Jet propulsion without inertia

    E-print Network

    Spagnolie, Saverio E

    2010-01-01

    A body immersed in a highly viscous fluid can locomote by drawing in and expelling fluid through pores at its surface. We consider this mechanism of jet propulsion without inertia in the case of spheroidal bodies, and derive both the swimming velocity and the hydrodynamic efficiency. Elementary examples are presented, and exact axisymmetric solutions for spherical, prolate spheroidal, and oblate spheroidal body shapes are provided. In each case, entirely and partially porous (i.e. jetting) surfaces are considered, and the optimal jetting flow profiles at the surface for maximizing the hydrodynamic efficiency are determined computationally. The maximal efficiency which may be achieved by a sphere using such jet propulsion is 12.5%, a significant improvement upon traditional flagella-based means of locomotion at zero Reynolds number. Unlike other swimming mechanisms which rely on the presentation of a small cross section in the direction of motion, the efficiency of a jetting body at low Reynolds number increas...

  11. Instability analysis of an inner-driving coaxial jet inside a coaxial electrode for the non-equipotential case

    Microsoft Academic Search

    Fang Li; Xie-Yuan Yin; Xie-Zhen Yin

    2008-01-01

    In this paper, the temporal linear stability analysis of a coaxial jet with two coflowing immiscible liquids inside a coaxial electrode is carried out to investigate the non-equipotential case of the inner-driving coaxial electrospray. Accordingly the outer liquid is assumed to be insulating and the inner liquid as the driving medium with finite conductivity. However, the current due to conduction

  12. Critical condition for the transformation from Taylor cone to cone-jet

    NASA Astrophysics Data System (ADS)

    Wei, Cheng; Gang, Tie-Qiang; Chen, Li-Jie; Zhao, Yang

    2014-06-01

    An energy method is proposed to investigate the critical transformation condition from a Taylor cone to a cone-jet. Based on the kinetic theorem, the system power allocation and the electrohydrodynamics stability are discussed. The numerical results indicate that the energy of the liquid cone tip experiences a maximum value during the transformation. With the proposed jetting energy, we give the critical transformation condition under which the derivative of jetting energy with respect to the surface area is greater than or equal to the energy required to form a unit of new liquid surface.

  13. Manipulation of an axisymmetric jet using continuous control jets

    Microsoft Academic Search

    David A. Tamburello; Michael Amitay

    2006-01-01

    The mechanisms associated with the interaction of an axisymmetric free jet (de = 4 mm; ReUe = 26 500 and 6600) with two continuous control jets on mixing, spreading and direction were examined experimentally. The flow field was visualized and measured using particle image velocimetry, where the interaction of the main jet with the control jets was investigated for different

  14. Beating the jetting regime Beating the jetting regime

    E-print Network

    Paris-Sud XI, Université de

    at the tip of the inner capillary and the resulting emulsion drops are monodisperse in size. In the jetting regime, a jet is formed at the tip of the inner capillary; the jet often breaks up into droplets-uniform and different from the size of the inner tip2,3 . The mechanism of the dripping and jetting regimes are quite

  15. Electromagnetic jet-propulsion in the direction of current flow

    Microsoft Academic Search

    Peter Graneau

    1982-01-01

    Two simple experiments are reported here which demonstrate jet-propulsion in the direction of current flow between liquid and solid conductors. The observed effects seem to conform with Ampere's force-law, but no qualitative nor quantitative explanation has so far been found in terms of lorentzian forces and associated magnetohydrodynamics (MHD) phenomena. This research forms part of a wider investigation of the

  16. Optimal Jet Finder

    NASA Astrophysics Data System (ADS)

    Grigoriev, D. Yu.; Jankowski, E.; Tkachov, F. V.

    2003-09-01

    We describe a FORTRAN 77 implementation of the optimal jet definition for identification of jets in hadronic final states of particle collisions. We discuss details of the implementation, explain interface subroutines and provide a usage example. The source code is available from http://www.inr.ac.ru/~ftkachov/projects/jets/. Program summaryTitle of program: Optimal Jet Finder (OJF_014) Catalogue identifier: ADSB Program Summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSB Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer: Any computer with the FORTRAN 77 compiler Tested with: g77/Linux on Intel, Alpha and Sparc; Sun f77/Solaris (thwgs.cern.ch); xlf/AIX (rsplus.cern.ch); MS Fortran PowerStation 4.0/Win98 Programming language used: FORTRAN 77 Memory required: ˜1 MB (or more, depending on the settings) Number of bytes in distributed program, including examples and test data: 251 463 Distribution format: tar gzip file Keywords: Hadronic jets, jet finding algorithms Nature of physical problem: Analysis of hadronic final states in high energy particle collision experiments often involves identification of hadronic jets. A large number of hadrons detected in the calorimeter is reduced to a few jets by means of a jet finding algorithm. The jets are used in further analysis which would be difficult or impossible when applied directly to the hadrons. Grigoriev et al. [ hep-ph/0301185] provide a brief introduction to the subject of jet finding algorithms and a general review of the physics of jets can be found in [Rep. Prog. Phys. 36 (1993) 1067]. Method of solution: The software we provide is an implementation of the so-called optimal jet definition ( OJD). The theory of OJD was developed by Tkachov [Phys. Rev. Lett. 73 (1994) 2405; 74 (1995) 2618; Int. J. Mod. Phys. A 12 (1997) 5411; 17 (2002) 2783]. The desired jet configuration is obtained as the one that minimizes ? R, a certain function of the input particles and jet configuration. Restrictions on the complexity of the program: The size of the largest data structure the program uses is (maximal number of particles in the input) × (maximal number of jets in the output) × 8 bytes. (For the standard settings <1 MB). Therefore, there is no memory restriction for any conceivable application for which the program was designed. Typical running time: The running time depends strongly on the physical process being analyzed and the parameters used. For the benchmark process we studied, e+e-? W+W-? 4 jets , with the average number of ˜80 particles in the input, the running time was <10 -2 s on a modest PC (per event with ntries=1). For a fixed number of jets the complexity of the algorithm grows linearly with the number of particles (cells) in the input, in contrast with other known jet finding algorithms for which this dependence is cubic. The reader is referred to Grigoriev et al. [ hep-ph/0301185] for a more detailed discussion of this issue.

  17. Relativistic AGN jets - II. Jet properties and mixing effects for episodic jet activity

    NASA Astrophysics Data System (ADS)

    Walg, S.; Achterberg, A.; Markoff, S.; Keppens, R.; Porth, O.

    2014-04-01

    Various radio galaxies show signs of having gone through episodic jet outbursts in the past. An example is the class of double-double radio galaxies (DDRGs). However, to follow the evolution of an individual source in real-time is impossible due to the large time-scales involved. Numerical studies provide a powerful tool to investigate the temporal behaviour of episodic jet outbursts in a (magneto)hydrodynamical setting. We simulate the injection of two jets from active galactic nuclei (AGNs), separated by a short interruption time. Three different jet models are compared. We find that an AGN jet outburst cycle can be divided into four phases. The most prominent phase occurs when the restarted jet is propagating completely inside the hot and inflated cocoon left behind by the initial jet. In that case, the jet-head advance speed of the restarted jet is significantly higher than the initial jet-head. While the head of the initial jet interacts strongly with the ambient medium, the restarted jet propagates almost unimpeded. As a result, the restarted jet maintains a strong radial integrity. Just a very small fraction of the amount of shocked jet material flows back through the cocoon compared to that of the initial jet and much weaker shocks are found at the head of the restarted jet. We find that the features of the restarted jet in this phase closely resemble the observed properties of a typical DDRG.

  18. Microbicidal activities of low frequency atmospheric pressure plasma jets on oral pathogens.

    PubMed

    Yamazaki, Hiromitsu; Ohshima, Tomoko; Tsubota, Yuji; Yamaguchi, Hiroyasu; Jayawardena, Jayanetti Asiri; Nishimura, Yasushi

    2011-01-01

    Research using low frequency atmospheric pressure plasma jets (LF jet) is becoming increasingly more common. We carried out experiments to evaluate the sterilizing effects of this technology on oral pathogenic microorganisms (S.mutans, C.albicans and E. faecalis) and to determine its potential for clinical application. We performed the direct exposure test on a solid surface, indirect exposure test on a liquid phase, and ROS (reactive oxygen species) inhibitory test. The results showed the LF jet had microbicidal effects on oral pathogens, and that the ROS influenced this sterilization effect. The experiments of this study revealed that LF jet had a sterilizing effect on oral pathogenic microorganisms present in both the solid and liquid phases. The sterilizing mechanism was considered to be related to the effect of superoxide anion radicals. These results indicate that LF jets may represent a novel technology that can be applied to the field of clinical dentistry. PMID:21597211

  19. Relativistic jets from supernovae

    NASA Astrophysics Data System (ADS)

    Gomez, Enrique Alberto

    Stars with masses greater than eight times the Sun's explode as supernovae when they fail to extract energy from nuclear fusion. Some of these supernova progenitors shed their outermost hydrogen envelope and acquire high rates of rotation at their cores before they explode. During a supernova collapse phase these stars form a dense disk of material around a degenerate core, which in turn powers energetic jets of material that propagate through the stellar atmosphere outwards. These jets soon acquire bulk speeds close to the speed of light. We perform a detailed analysis of numerical, hydrodynamic simulations of these jets to determine their stability to pressure waves that grow as Kelvin- Helmholtz modes from the interface between the jet and the stellar medium. We have discovered that the pressure profile of the star makes these jets unstable to such modes just before the jet breaks out compared to the region closest to the center. We have also discovered that only the most energetic jets predicted in this theory support such modes over the time it takes for the jet to reach the stellar surface. When we follow the jets in the numerical simulations as they break out, we calculate that they become relativistic winds that carry within them enhancements in their pressure and velocity, which can turn into internal shocks. These shocks could accelerate charged particles that cool through gamma ray emission and thus convert the kinetic energy of the wind into radiation that we can detect as a long gamma-ray burst. However, we have found that the fastest moving core of this wind is unlikely to produce substantial internal shocks. Shocks are most likely to happen at an angle from the center of a conical wind. We present a test of this model for such emission geometry and its corresponding rate for detected gamma ray bursts above a given gamma-ray flux.

  20. Multiple jet interactions

    E-print Network

    Hehr, Roger James

    1983-01-01

    Multiple Jet Interactions. (August 1983) Roger James Hehr, B. S. , Texas A&M University Chairman of Advisory Committee: Dr. David J. Norton An experimental study to determine the effects of changing the nozzle separation ratio, h/D, of a linear array... of round jets on the veloc1ty field 40 nozzle diameters downstream of the nozzle exits was conducted. An init1al study of the individual jets comprisino the array was also conducted to provide a basis of comparison for future stud1es and for ver1ficat1...

  1. ATLAS Jet Energy Scale

    E-print Network

    D. Schouten; A. Tanasijczuk; M. Vetterli; for the ATLAS Collaboration

    2012-01-11

    Jets originating from the fragmentation of quarks and gluons are the most common, and complicated, final state objects produced at hadron colliders. A precise knowledge of their energy calibration is therefore of great importance at experiments at the Large Hadron Collider at CERN, while is very difficult to ascertain. We present in-situ techniques and results for the jet energy scale at ATLAS using recent collision data. ATLAS has demonstrated an understanding of the necessary jet energy corrections to within \\approx 4% in the central region of the calorimeter.

  2. Status of jet noise

    NASA Technical Reports Server (NTRS)

    Banerian, G.

    1977-01-01

    The fundamentals of jet noise generation and suppression have been studied in great detail over the past twenty-five years. Considerable progress has been made recently in our understanding of this subject, though some aspects of it remain perplexing. The importance of accounting for the influence of the jets mean flow in shrouding acoustic sources is now recognized and the large amount of information obtained on jet noise reduction schemes, e.g., the internal mixer nozzle, the inverted profile nozzle and multi-element suppressors, has helped clarify trends and identify remaining issues. Current understanding of inflight effects is limited and in need of much more attention.

  3. Instability of a viscous coflowing jet in a radial electric field

    Microsoft Academic Search

    Fang Li; Xie-Yuan Yin; Xie-Zhen Yin

    2008-01-01

    A temporal linear instability analysis of a charged coflowing jet with two immiscible viscous liquids in a radial electric field is carried out for axisymmetric disturbances. According to the magnitude of the liquid viscosity relative to the ambient air viscosity, two generic cases are considered. The analytical dimensionless dispersion relations are derived and solved numerically. Two unstable modes, namely the

  4. The JPL Direct Methanol Liquid-feed PEM Fuel Cell

    NASA Technical Reports Server (NTRS)

    Halpert, G.; Surampudi, S.

    1994-01-01

    Recently, there has been a breakthrough in fuel cell technology in the Energy Storage Systems Group at the Jet Propulsion Laboratory with the develpment of a direct methanol, liquid-feed, solid polymer electrolyte membrane (PEM) fuel cell... The methanol liquid-feed, solid polymer electrolyte (PEM) design has numerous system level advantages over the gas-feed design. These include:...

  5. IMPINGING JET DRYER

    Microsoft Academic Search

    Satoru INOUE; Kauuhide EGUCHI; Tsunehiko IMAMOTO; Mitsunori KlSHI

    1992-01-01

    In coating and gravure printing, an impinging jet nozzle with high thermal efficiency for drying of coated film was developed.Trial production 0f 40 kinds of nozzle enables to develop a high-performance impinging jet nozzle with heat transfer coefficient 1.5 times larger than that of current slit nozzle, through measurement of heat transfer coefficient, visualizations of air flow and heat transfer,

  6. Multiple jet interactions 

    E-print Network

    Hehr, Roger James

    1983-01-01

    MULTIPLE JET INTERACTIONS A Thesis by ROGER JAMES HEHR Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1983 Major Subject: Aerospace Engineering... augmenting ejector systems in 3 such aircraft as the Mar1ne Corps/McDonnell Douglas AV-BB "Harrier". Schetz and Krzywoblocki present comprehensive reviews on the 2 4 works published concerning jets. The theoretical and experimental work relevant...

  7. Influence of a sample surface on single electrode atmospheric plasma jet parameters

    NASA Astrophysics Data System (ADS)

    Zaplotnik, Rok; Biš?an, Marijan; Kregar, Zlatko; Cvelbar, Uroš; Mozeti?, Miran; Miloševi?, Slobodan

    2015-01-01

    The article reports on reciprocal influence between the sample surface and atmospheric plasma jet. This correlation is important since it changes plasma parameters and plasma itself, depending on the sample-material surface, presence of liquid or treatment distance. However, in experiments and treatments of surfaces with atmospheric plasma jets, this relationship is usually disregarded. In order to investigate reciprocal influence, we implemented electromagnetic and optical emission spectroscopy characterization of atmospheric plasma needle jet. Characterization was performed during treatment of various samples. We have shown that sample material and its distance from the tip of the electrode have a pronounced influence on atmospheric pressure plasma jet electromagnetic and optical characteristics, such as jet length, shape, color, voltage, current, power, electromagnetic field and concentrations of plasma species. It was shown that for a given flow there is a critical distance (? 15 mm) between the tip of the wire and the sample surface for which jet emission intensity, especially ionic, is at maximum.

  8. Electrical Properties of Reactive Liquid Crystal Semiconductors

    Microsoft Academic Search

    Iain McCulloch; Michael Coelle; Kristijonas Genevicius; Rick Hamilton; Michael Heckmeier; Martin Heeney; Theo Kreouzis; Maxim Shkunov; Weimin Zhang

    2008-01-01

    Fabrication of display products by low cost printing technologies such as ink jet, gravure offset lithography and flexography requires solution processable semiconductors for the backplane electronics. The products will typically be of lower performance than polysilicon transistors, but comparable to amorphous silicon. A range of prototypes are under development, including rollable electrophoretic displays, active matrix liquid crystal displays (AMLCD's), and

  9. Combined plasma/liquid cleaning of substrates

    DOEpatents

    Selwyn, Gary S. (Los Alamos, NM); Henins, Ivars (Los Alamos, NM)

    2003-04-15

    Apparatus and method for cleaning substrates. A substrate is held and rotated by a chuck and an atmospheric pressure plasma jet places a plasma onto predetermined areas of the substrate. Subsequently liquid rinse is sprayed onto the predetermined areas. In one embodiment, a nozzle sprays a gas onto the predetermined areas to assist in drying the predetermined areas when needed.

  10. Flow focusing with viscoelastic liquids

    NASA Astrophysics Data System (ADS)

    Derzsi, Ladislav; Kasprzyk, Marta; Plog, Jan Philip; Garstecki, Piotr

    2013-09-01

    We present an experimental comparative study of the effect of elasticity of the continuous liquid in generation of droplets in microfluidic flow focusing devices. For a wide range of values of dynamic viscosity of the Newtonian droplet phase we compare the dynamics of the formation of droplets in three different Newtonian and non-Newtonian, viscoelastic (Boger) fluid pairs of the same (and nearly constant) shear viscosities. In both Newtonian and viscoelastic systems we find similar regimes of operation of the system: (i) dripping without satellites, (ii) dripping with single satellites, (iii) formation of multiple satellites, and (iv) jetting. We find that the elasticity of the focusing liquid stabilizes the jets facilitating formation of smaller droplets, and leads to transitions between various regimes at lower ratios of flow and at lower values of the capillary numbers in comparison to the Newtonian focusing liquids. We also show that the polydispersity of Newtonian droplets produced in non-Newtonian continuous phases depend significantly on the viscosity of the droplet phase while this dependence is minor when the continuous liquid is Newtonian.

  11. Shock-induced bubble jetting into a viscous fluid with application to tissue injury in shock-wave lithotripsy

    E-print Network

    Freund, Jonathan B.

    Shock-induced bubble jetting into a viscous fluid with application to tissue injury in shock, Indiana 46202 Received 22 April 2009; revised 18 August 2009; accepted 19 August 2009 Shock waves in the direction of the propagating shock. The interaction of these jets with an adjacent viscous liquid

  12. Study of Chromospheric Jets

    NASA Astrophysics Data System (ADS)

    Lee, Chik-Yin; Johannesson, Anders; Wang, Haimin; Stage, Mike; Zirin, Hal

    1997-05-01

    In this paper we present a new fast spectral scan method to study H? jets, which are more energetic than regular spicules. The observations achieved high two-dimensional spatial resolution, temporal resolution and spectral resolution simultaneously. We used the Coude spectrograph in the Big Bear Solar Observatory for the H? data acquisition. The procedure starts with fast spectral scans across the solar surface (600" by 300") at the vicinity of the solar disk center. The guiding system is turned off allowing the Sun to drift smoothly relative to the spectrograph system. A total number of 600 spectral images at 6563A are recorded per scan on an optical disk recorder at a rate of 30 frames/sec. Tracking re-position the system to point to the same initial coordinates on the Sun for new scans. The process repeats every 30 seconds until 60 scans are completed. The stored images are digitized for off-line data analysis. A number of different image processing techniques are used to improve the image quality. These include off-line correlation tracking and running average among various constructed images. From the four-dimensional (x,y,t,wavelength) H? data arrays, we can reconstruct spectroheliograms (600 by 240 pixels) at different wavelengths. We calculate velocities of jets by measuring Doppler shifts of the H? absorption line, where we used an optically thin jet model. Velocities of 30 to 50 km/sec for jets are derived. Velocity maps are constructed thereafter for the scanned region, and are compiled as movies. We measure the lifetime and size of the jets from these movies. Lifetimes of a few minutes are observed. Further approximations are made to find out temperature and density of jets by fitting the H? absorption line profile. The results will enable us to estimate the total mechanical energy released by the jets.

  13. Liquid-Liquid Extraction Processes 

    E-print Network

    Fair, J. R.; Humphrey, J. L.

    1983-01-01

    the two liquid phases, separation will result. This is the principle upon which separation by liquid-liquid extraction is based, and there are a number of important applications of this concept in industrial processes. This paper will review the basic...

  14. Fractal Liquids

    E-print Network

    Marco Heinen; Simon K. Schnyder; John F. Brady; Hartmut Löwen

    2015-05-05

    We introduce fractal liquids by generalizing classical liquids of integer dimensions $d = 1, 2, 3$ to a fractal dimension $d_f$. The particles composing the liquid are fractal objects and their configuration space is also fractal, with the same non-integer dimension. Realizations of our generic model system include microphase separated binary liquids in porous media, and highly branched liquid droplets confined to a fractal polymer backbone in a gel. Here we study the thermodynamics and pair correlations of fractal liquids by computer simulation and semi-analytical statistical mechanics. Our results are based on a model where fractal hard spheres move on a near-critical percolating lattice cluster. The predictions of the fractal Percus-Yevick liquid integral equation compare well with our simulation results.

  15. B-jets and z + b-jets at CDF

    SciTech Connect

    Jeans, Daniel; /Rome U.

    2006-06-01

    The authors present CDF cross-section measurements for the inclusive production of b jets and the production of b jets in association with a Z{sup 0} boson. Both measurements are in reasonable agreement with NLO QCD predictions.

  16. The M87 Jet. "Rosetta Stone" of AGN Jets

    NASA Astrophysics Data System (ADS)

    Nakamura, Masanori; Asada, Keiichi

    2013-12-01

    We investigate the structure and dynamics of the M87 jet based on multi-frequency VLBI observations and MHD jet theories. Millimeter VLBI cores are considered as innermost jet emissions. The jet structure up to ~ 105 rs is described as a parabolic streamline, indicating the lateral expansion under a confinement by the stratified ISM. Thus, the jet collimation maintains in five orders of magnitude in the distance starting from the vicinity of the supermassive black hole (SMBH), less than 10 rs. We here examine the jet parabolic structure in order to identify the property of a bulk acceleration; observed sub-to-superluminal motions indicate an MHD acceleration from non-relativistic to relativistic regimes. We propose that the M87 jet consists of Poynting-flux dominated flows, powered by nonlinear torsional Alfvén waves. Future sub-mm VLBI observations play an important role in resolving the origin of the M87 jets.

  17. Photographic copy of photograph, aerial view looking down at Jet ...

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

    Photographic copy of photograph, aerial view looking down at Jet Propulsion Laboratory, Edwards Test Station complex in 1961, with north toward the top of the view. Dd test station has been added to Test Stand 'D,' liquid nitrogen storage facility E-63 has been built, as well as several adjuncts to Test Stand 'C' behind earth barriers, such as oxidizer facility at 4263/E-64 and hydrogen tank at 4264/E-65. (JPL negative no. 384-3003-A, 12 December 1961) - Jet Propulsion Laboratory Edwards Facility, Edwards Air Force Base, Boron, Kern County, CA

  18. Gudrun's (NLO) list pp->WW jet

    E-print Network

    Huston, Joey

    Gudrun's (NLO) list 2->3 pp->WW jet pp->VVV pp->H + 2 jets 2->4 pp->4 jets pp->tT + 2jets p->tT bB pp->V+ 3 jets pp->VV + 2 jets pp->VVV + jet pp->WW bB From technology point-of-view start and/or subprocesses) W + 3 jets pp->4 jets WW + 2 jets tT + 2 jets tT bB WWbB can be given

  19. Aeroacoustic Experiments with Twin Jets

    NASA Technical Reports Server (NTRS)

    Bozak, Richard F.; Henderson, Brenda S.

    2012-01-01

    While the noise produced by a single jet is azimuthally symmetric, multiple jets produce azimuthally varying far-field noise. The ability of one jet to shield another reduces the noise radiated in the plane of the jets, while often increasing the noise radiated out of the plane containing the jets. The present study investigates the shielding potential of twin jet configurations over subsonic and over-expanded supersonic jet conditions with simulated forward flight. The experiments were conducted with 2 in. throat diameter nozzles at four jet spacings from 2.6d to 5.5d in center-to-center distance, where d is the nozzle throat diameter. The current study found a maximum of 3 dB reduction in overall sound pressure level relative to two incoherent jets in the peak jet noise direction in the plane containing the jets. However, an increase of 3 dB was found perpendicular to the plane containing the jets. In the sideline direction, shielding is observed for all jet spacings in this study.

  20. Active control of a free jet using a synthetic jet

    Microsoft Academic Search

    David A. Tamburello; Michael Amitay

    2008-01-01

    The control of an axisymmetric free jet (ReUe=6600) using a single synthetic jet was investigated experimentally. The interaction was examined for a range of momentum coefficients, Strouhal numbers, and synthetic jet orientations (with respect to the main jet). To better explore the complex flow field resulting from the interaction, a rendering technique was used where three-dimensional flow fields were calculated

  1. Elliptic jets. I - Characteristics of unexcited and excited jets

    NASA Technical Reports Server (NTRS)

    Hussain, Fazle; Husain, Hyder S.

    1989-01-01

    Experimental studies of incompressible elliptic jets of different aspect ratios and initial conditions are summarized along with the effects of excitations at selected frequencies and amplitudes. The experimental facilities and procedures are described and jet spread and decay are discussed. The instability of elliptic shear layers, the behavior of the jet column under controlled excitation, and the time-average measures of unexcited jets are addressed.

  2. The experimental assessment of jet transverse velocity

    NASA Astrophysics Data System (ADS)

    Summers, Richard L.; Wright, Kipp C.

    Shaped charge jets exhibit a velocity gradient from tip to tail, stretching the jet until it particulates. After particulation, jet particle tumble and lack of jet straightness degrade penetration. Jet straightness is characterized by the transverse velocities of the jet particles. The measurement of jet transverse velocity requires a great deal of experimental precision. An experimental method involving flash x-ray equipment for the measurement of transverse velocity is presented. In addition, the mechanisms which induce jet transverse velocities are discussed.

  3. The Cape Tobin Jet

    NASA Astrophysics Data System (ADS)

    Ólafsson, H.; Shapiro, M. A.; Ágústsson, H.; Kristjánsson, J. E.

    2009-04-01

    In northerly flow, a strong jet close to Cape Tobin in E-Greenland is frequently simulated in numerical weather prediction models. To the extent that the late-summer absence of sea-ice permits, Quik-SCAT observations confirm the presence of this jet. During the IPY/THORPEX and GREENEX campaigns in March 2008, observations were made of the Cape Tobin jet with a number of dropsondes. The core of the jet with maximum wind speed of about 45 m/s was located at a strong inversion at about 1 km above the sea ice. The inversion slopes and is at a lower level away from Greenland than closer to the coast. A part of the Tobin jet impinges on the more than 2 km high topography of E-Greenland and flows over it in spite of high static stability. The associated mixing leads to cooling of the layers between 1 and 2 km and the downstream flow at these levels may be characterized as "cold foehn".

  4. Jet penetration in glass

    SciTech Connect

    Moran, B.; Glenn, L.A.; Kusubov, A.

    1991-05-01

    We describe a phenomenological model which accounts for the mechanical response of glass to intense impulsive loading. An important aspect of this response is the dilatancy accompanying fracture. We have also conducted a number of experiments with 38.1-mm diameter precision shaped charges to establish the performance against various targets and to allow evaluation of our model. At 3 charge diameters standoff, the data indicate that both virgin and damaged glass offer better (Bernoulli-scaled) resistance to penetration than either of 4340 steel, or 6061-T6 aluminum alloy. Time-resolved measurements indicate two distinct phases of jet penetration in glass: An initial hydrodynamic phase, and a second phase characterized by a slower penetration velocity. Our calculations show that at early time, a crater is formed around the jet and only the tip of the undisturbed jet interacts with the glass. At late time the glass has collapsed on the jet and degraded penetration continues via a disturbed and fragmented jet.

  5. Jet propulsion without inertia

    E-print Network

    Saverio E. Spagnolie; Eric Lauga

    2010-05-04

    A body immersed in a highly viscous fluid can locomote by drawing in and expelling fluid through pores at its surface. We consider this mechanism of jet propulsion without inertia in the case of spheroidal bodies, and derive both the swimming velocity and the hydrodynamic efficiency. Elementary examples are presented, and exact axisymmetric solutions for spherical, prolate spheroidal, and oblate spheroidal body shapes are provided. In each case, entirely and partially porous (i.e. jetting) surfaces are considered, and the optimal jetting flow profiles at the surface for maximizing the hydrodynamic efficiency are determined computationally. The maximal efficiency which may be achieved by a sphere using such jet propulsion is 12.5%, a significant improvement upon traditional flagella-based means of locomotion at zero Reynolds number. Unlike other swimming mechanisms which rely on the presentation of a small cross section in the direction of motion, the efficiency of a jetting body at low Reynolds number increases as the body becomes more oblate, and limits to approximately 162% in the case of a flat plate swimming along its axis of symmetry. Our results are discussed in the light of slime extrusion mechanisms occurring in many cyanobacteria.

  6. The Twin Jet Nebula

    NASA Technical Reports Server (NTRS)

    1997-01-01

    M2-9 is a striking example of a 'butterfly' or a bipolar planetary nebula. Another more revealing name might be the 'Twin Jet Nebula.' If the nebula is sliced across the star, each side of it appears much like a pair of exhausts from jet engines. Indeed, because of the nebula's shape and the measured velocity of the gas, in excess of 200 miles per second, astronomers believe that the description as a super-super-sonic jet exhaust is quite apt. This is much the same process that takes place in a jet engine: The burning and expanding gases are deflected by the engine walls through a nozzle to form long, collimated jets of hot air at high speeds. M2-9 is 2,100 light-years away in the constellation Ophiucus. The observation was taken Aug. 2, 1997 by the Hubble telescope's Wide Field and Planetary Camera 2. In this image, neutral oxygen is shown in red, once-ionized nitrogen in green, and twice-ionized oxygen in blue.

  7. Liquid injection plasma deposition method and apparatus

    DOEpatents

    Kong, Peter C. (Idaho Falls, ID); Watkins, Arthur D. (Idaho Falls, ID)

    1999-01-01

    A liquid injection plasma torch deposition apparatus for depositing material onto a surface of a substrate may comprise a plasma torch for producing a jet of plasma from an outlet nozzle. A plasma confinement tube having an inlet end and an outlet end and a central bore therethrough is aligned with the outlet nozzle of the plasma torch so that the plasma jet is directed into the inlet end of the plasma confinement tube and emerges from the outlet end of the plasma confinement tube. The plasma confinement tube also includes an injection port transverse to the central bore. A liquid injection device connected to the injection port of the plasma confinement tube injects a liquid reactant mixture containing the material to be deposited onto the surface of the substrate through the injection port and into the central bore of the plasma confinement tube.

  8. Liquid injection plasma deposition method and apparatus

    DOEpatents

    Kong, P.C.; Watkins, A.D.

    1999-05-25

    A liquid injection plasma torch deposition apparatus for depositing material onto a surface of a substrate may comprise a plasma torch for producing a jet of plasma from an outlet nozzle. A plasma confinement tube having an inlet end and an outlet end and a central bore therethrough is aligned with the outlet nozzle of the plasma torch so that the plasma jet is directed into the inlet end of the plasma confinement tube and emerges from the outlet end of the plasma confinement tube. The plasma confinement tube also includes an injection port transverse to the central bore. A liquid injection device connected to the injection port of the plasma confinement tube injects a liquid reactant mixture containing the material to be deposited onto the surface of the substrate through the injection port and into the central bore of the plasma confinement tube. 8 figs.

  9. Studies of turbulent round jets through experimentation, simulation, and modeling

    NASA Astrophysics Data System (ADS)

    Keedy, Ryan

    This thesis studies the physics of the turbulent round jet. In particular, it focuses on three different problems that have the turbulent round jet as their base flow. The first part of this thesis examines a compressible turbulent round jet at its sonic condition. We investigate the shearing effect such a jet has when impinging on a solid surface that is perpendicular to the flow direction. We report on experiments to evaluate the jet's ability to remove different types of explosive particles from a glass surface. Theoretical analysis revealed trends and enabled modeling to improve the predictability of particle removal for various jet conditions. The second part of thesis aims at developing a non-intrusive measurement technique for free-shear turbulent flows in nature. Most turbulent jet investigations in the literature, both in the laboratory and in the field, required specialized intrusive instrumentation and/or complex optical setups. There are many situations in naturally-occurring flows where the environment may prove too hostile or remote for existing instrumentation. We have developed a methodology for analyzing video of the exterior of a naturally-occurring flow and calculating the flow velocity. We found that the presence of viscosity gradients affects the velocity analysis. While these effects produce consistent, predictable changes, we became interested in the mechanism by which the viscosity gradients affect the mixing and development of the turbulent round jet. We conducted a stability analysis of the axisymmetric jet when a viscosity gradient is present. Finally, the third problem addressed in this thesis is the growth of liquid droplets by condensation in a turbulent round jet. A vapor-saturated turbulent jet issues into a cold, dry environment. The resulting mixing produces highly inhomogeneous regions of supersaturation, where droplets grow and evaporate. Non-linear interactions between the droplet growth rate and the supersaturation field make analysis computationally taxing. A Probability Density Function (PDF) model for the concentration of scalars, as well as for the droplet number in different size bins, is developed. The growth of droplets as they evolve along the jet, for different downstream and radial positions, compared favorably with experimental measurements in the literature. We utilized a graphical processing unit with the PDF method to more efficiently compute the statistics of the droplet diameter in the non-uniform supersaturation field.

  10. The cavitating submerged jet

    SciTech Connect

    Franklin, R.E. [Univ. of Oxford (United Kingdom). Engineering Lab.

    1994-12-31

    This paper reviews the results of a long-term program of research into the inception and development of cavitation in the submerged jet, the diagnostic for the cavitation being the pressure fluctuations in the near field of the jet. A revised and extended theoretical analysis is presented which shows that the cavitation does not depend simply on the cavitation number of the flow, but also on a Weber number based on the ambient pressure and the jet diameter, and the total dissolved gas content measured relative to the saturation concentration at the ambient pressure. The analysis not only predicts the nondimensional numbers which correlate the experimental data over wide ranges of the principal variables, but also the form of the curve to which the data collapse.

  11. Renewable jet fuel.

    PubMed

    Kallio, Pauli; Pásztor, András; Akhtar, M Kalim; Jones, Patrik R

    2014-04-01

    Novel strategies for sustainable replacement of finite fossil fuels are intensely pursued in fundamental research, applied science and industry. In the case of jet fuels used in gas-turbine engine aircrafts, the production and use of synthetic bio-derived kerosenes are advancing rapidly. Microbial biotechnology could potentially also be used to complement the renewable production of jet fuel, as demonstrated by the production of bioethanol and biodiesel for piston engine vehicles. Engineered microbial biosynthesis of medium chain length alkanes, which constitute the major fraction of petroleum-based jet fuels, was recently demonstrated. Although efficiencies currently are far from that needed for commercial application, this discovery has spurred research towards future production platforms using both fermentative and direct photobiological routes. PMID:24679258

  12. On magnetohydrodynamic solitons in jets

    NASA Technical Reports Server (NTRS)

    Roberts, B.

    1987-01-01

    Nonlinear solitary wave propagation in a compressible magnetic beam model of an extragalactic radio jet is examined and shown to lead to solitons of the Benjamin-Ono type. A number of similarities between such magnetic beam models of jets and models of solar photospheric flux tubes are pointed out and exploited. A single soliton has the appearance of a symmetric bulge on the jet which propagates faster than the jet's flow.

  13. Jet exhaust noise suppressor

    NASA Technical Reports Server (NTRS)

    Huff, R. G. (inventor)

    1974-01-01

    Noise suppression for a jet engine exhaust is provided by an annular divergent body attached to an exhaust nozzle. The smallest diameter of the divergent body is larger than the diameter of the exhaust nozzle exit to form an annular step which produces a shock wave in the exhaust as it passes the step. An annular shroud is disposed around the divergent body and causes outside air to pass through voids in the divergent body to mix with the jet exhaust gas. The divergent body includes a plurality of channels with separators between the channels.

  14. Incoherence of shaped charge jets

    Microsoft Academic Search

    James D. Walker

    1994-01-01

    It has been known for many years that some shaped charge geometries produce a radially expanding jet, referred to as jet incoherence. Incoherence greatly reduces the penetration capability of a jet. Experimentally, incoherence has been related to the sound speed of the material. In this paper, it is shown that the radial expansion is due to the conditions of the

  15. Jet Propulsion Laboratory Introduction 1

    E-print Network

    Waliser, Duane E.

    JPL Annual Report 1989 Jet Propulsion Laboratory #12;#12;CONTENTS Introduction 1 Director's Message for the period January 1 through December 31, 1989. JET PROPULSION LABORATORY California Institute of Technology Pasadena, California #12;INTRODUCTION TheJet Propulsion Laboratory QPL) of the California Institute

  16. Liquid membranes

    SciTech Connect

    Araki, T. (Kyoto Inst. of Tech. (Japan)); Tsukube, H. (Okayama Univ. (Japan))

    1990-01-01

    This work describes newer applications of liquid membrane systems which contain molecular and/or ion recognizing carrier compounds and the related characteristic membrane materials. It focuses on the current knowledge about chemistry, biology and related technology of liquid membranes. It reviews the most recent advances in design and characteristics of synthetic liquid membrane transport. Up-to-date topics in the analytical and separation science, plus biomimetic membrane technology are discussed.

  17. Jet-Images: Computer Vision Inspired Techniques for Jet Tagging

    E-print Network

    Cogan, Josh; Strauss, Emanuel; Schwarztman, Ariel

    2014-01-01

    We introduce a novel approach to jet tagging and classification through the use of techniques inspired by computer vision. Drawing parallels to the problem of facial recognition in images, we define a jet-image using calorimeter towers as the elements of the image and establish jet-image preprocessing methods. For the jet-image processing step, we develop a discriminant for classifying the jet-images derived using Fisher discriminant analysis. The effectiveness of the technique is shown within the context of identifying boosted hadronic W boson decays with respect to a background of quark- and gluon- initiated jets. Using Monte Carlo simulation, we demonstrate that the performance of this technique introduces additional discriminating power over other substructure approaches, and gives significant insight into the internal structure of jets.

  18. In situ x-ray diffraction measurements of the capillary fountain jet produced via ultrasonic atomization.

    PubMed

    Yano, Yohko F; Douguchi, Junya; Kumagai, Atsushi; Iijima, Takao; Tomida, Yukinobu; Miyamoto, Toshiaki; Matsuura, Kazuo

    2006-11-01

    In situ x-ray diffraction measurements were carried out for investigating the liquid structure in the ultrasonic fountain jet to consider the mechanism of the "ultrasonic ethanol separation" reported by Sato et al. [J. Chem. Phys. 114, 2382 (2001)]. For pure liquids (water and ethanol), it was found that the high frequency ultrasound does not affect the liquid structure microscopically. For the 20 mol % ethanol-water mixture, the estimated ethanol mole fraction in the ultrasonic fountain jet by using the position of the main maximum in the x-ray diffraction profile coincided with that in the reservoir. This result suggests that the ethanol separation is not caused by any distorted liquid structure under the ultrasound irradiation and occurs when or after the generation of the liquid droplet mist. PMID:17100459

  19. Molecular dynamics of a water jet from a carbon nanotube.

    PubMed

    Hanasaki, Itsuo; Yonebayashi, Toru; Kawano, Satoyuki

    2009-04-01

    A carbon nanotube (CNT) can be viewed as a molecular nozzle. It has a cylindrical shape of atomistic regularity, and the diameter can be even less than 1 nm. We have conducted molecular-dynamics simulations of water jet from a (6,6) CNT that confines water in a form of single-file molecular chain. The results show that the water forms nanoscale clusters at the outlet and they are released intermittently. The jet breakup is dominated by the thermal fluctuations, which leads to the strong dependence on the temperature. The cluster size n decreases and the release frequency f increases at higher temperatures. The f roughly follows the reaction kinetics by the transition state theory. The speed of a cluster is proportional to the 1/sqrt[n] because of the central limit theorem. These properties make great contrast with the macroscopic liquid jets. PMID:19518333

  20. High-speed jet formation after solid object impact

    NASA Astrophysics Data System (ADS)

    Gekle, Stephan; Gordillo, José Manuel; van der Meer, Devaraj; Lohse, Detlef

    2007-11-01

    A circular disc impacting on a water surface creates a remarkably vigorous jet. Here we study this phenomenon in a controlled way by pulling the disc through the free surface at constant speed. An axisymmetric air-filled cavity is formed which eventually pinches off in a single point. Immediately after cavity closure the pinch-off location turns into a stagnation point and the flow pattern changes from radial sink flow into hyperbolic flow. The stagnation point deflects the incoming liquid leading to the formation of two fast sharp-pointed jets shooting up- and downwards from the closure point. We study the jet characteristics as a function of both impact velocity and disc radius.

  1. Development of droplet generator for liquid droplet radiator

    NASA Astrophysics Data System (ADS)

    Hosokawa, Shunsuke; Kawada, Masakuni; Iwasaki, Akira; Kudo, Isao

    A single-nozzle liquid droplet generator was fabricated and tested as part of a program aimed at the development of a liquid droplet generator for the liquid droplet radiator (LDR). The droplet generator uses diffusion pump oil as the working fluid. The pressurized oil is squirted from an orifice in the form of a liquid jet which is perturbed by an electrically driven oscillating piezoceramic disk. The growing oscillations eventually break up the liquid jet, and the droplets are formed with the same frequency as the oscillation. Results of vacuum chamber tests of the droplet generator indicate that the droplet velocity, droplet diameter, and the spacing between adjacent droplets satisfy the LDR design requirements.

  2. Jets and QSO Spectra

    NASA Astrophysics Data System (ADS)

    Wills, B. J.; Brotherton, M. S.

    QSOs' emission lines arise from highest velocity (approximately 10000 km/s), dense gas within approximately 0.1 parsec of the central engine, out to low-velocity, low-density gas at great distances from the host galaxy. In radio-loud QSOs there are clear indications that the distribution and kinematics of emission-line gas are related to the symmetry axis of the central engine, as defined by the radio jet. These jets originate at nuclear distances < 0.1 pc --- similar to the highest-velocity emission line gas. There are two ways we can investigate the different environments of radio-loud and radio-quiet QSOs, i.e., those with and without powerful radio jets. One is to look for optical-UV spectroscopic differences between radio-loud and radio-quiet QSOs. The other is to investigate dependences of spectroscopic properties on properties of the powerful jets in radio-loud QSOs. Here we summarize the spectroscopic differences between the two classes, and present known dependences of spectra on radio core-dominance, which we interpret as dependences on the angle of the central engine to the line-of-sight. We speculate on what some of the differences may mean.

  3. Jet Screech Noise Computation

    NASA Technical Reports Server (NTRS)

    Loh, Ching Y.; Hultgren, Lennart S.

    2003-01-01

    The near-field screech-tone noise of a typical underexpanded circular jet issuing from a sonic nozzle is simulated numerically. The self-sustained feedback loop is automatically established in the simulation. The computed shock-cell structure, acoustic wave length, screech tone frequencies, and sound pressure levels in the near field are in good agreement with existing experimental results.

  4. Particle Acceleration in Jets

    NASA Technical Reports Server (NTRS)

    Nishikawa, Ken-Ichi

    2005-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., active galactic nuclei (AGNs), gamma ray burst (GRBs), and Galactic microquasar systems usually have power-law emission spectra. Fermi acceleration is the mechanism usually assumed for the acceleration of particles in astrophysical environments.

  5. Spectroscopy with Supersonic Jets.

    ERIC Educational Resources Information Center

    Skinner, Anne R.; Chandler, Dean W.

    1980-01-01

    Discusses a new technique that enables spectroscopists to study gas phase molecules at temperatures below 1 K, without traditional cryogenic apparatus. This technique uses supersonic jets as samples for gas molecular spectroscopy. Highlighted are points in the theory of supersonic flow which are important for applications in molecular…

  6. Jet Propulsion Laboratory Homepage

    NSDL National Science Digital Library

    The Jet Propulsion Laboratory's (JPL) homepage provides links to spacecraft and mission information, imagery, news articles, events, features, and public services. Users can access articles and imagery from the Mars Rover and Cassini missions, images from the Spitzer Space Telescope, and an El Nino/La Nina Watch.

  7. Plasma control at JET

    Microsoft Academic Search

    M. Lennholm; T. Budd; R. Felton; M. Gadeberg; A. Goodyear; F. Milani; F. Sartori

    2000-01-01

    Joint European Torus (JET) discharges have plasma currents up to 6 MA and toroidal fields up to 4 T. The plasma parameters during discharges are determined by the action of a number of distinct systems. These systems can be divided into three groups; the toroidal and poloidal field systems; the fuelling systems; and the additional heating systems. The systems can

  8. Supersonic Plasma Jets

    Microsoft Academic Search

    John M. Foster

    2001-01-01

    Supersonic fluid flow and the interaction of strong shock waves to produce jets of material are ubiquitous features of Inertial Confinement Fusion (ICF) and astrophysical science. The availability of large high-energy laser systems provides the opportunity to investigate such hydrodynamic systems in the laboratory, and to test their modeling by radiation hydrocodes. We describe experiments to investigate the propagation of

  9. Structure, alteration, and geochemistry of the Charlotte quartz vein stockwork, Mt Charlotte gold mine, Kalgoorlie, Australia: time constraints, down-plunge zonation, and fluid source

    NASA Astrophysics Data System (ADS)

    Mueller, Andreas G.

    2015-02-01

    The Kalgoorlie district in the Archean Yilgarn Craton, Western Australia, comprises two world-class gold deposits: Mt Charlotte (144 t Au produced to 2013) in the northwest and the Golden Mile (1,670 t Au) in the southeast. Both occur in a folded greenschist-facies gabbro sill adjacent to the Golden Mile Fault (D2) in propylitic alteration associated with porphyry dikes. At Mt Charlotte, a shear array of fault-fill veins within the Golden Mile Fault indicates sinistral strike-slip during Golden Mile-type pyrite-telluride mineralization. The pipe-shaped Charlotte quartz vein stockwork, mined in bulk more than 1 km down plunge, is separated in time by barren D3 thrusts from Golden Mile mineralization and alteration, and occurs between two dextral strike-slip faults (D4). Movement on these faults generated an organized network of extension and shear fractures opened during the subsequent infiltration of high-pressure H2S-rich fluid at 2,655 ± 13 Ma (U-Pb xenotime). Gold was deposited during wall rock sulphidation in overlapping vein selvages zoned from deep albite-pyrrhotite (3 g/t Au) to upper muscovite-pyrite assemblages (5 g/t Au bulk grade). Chlorite and fluid inclusion thermometry indicate that this kilometre-scale zonation is due to fluid cooling from 410-440 °C at the base to 350-360 °C at the top of the orebody, while the greenstone terrane remained at 250 °C ambient temperature and at 300 MPa lithostatic pressure. The opened fractures filled with barren quartz and scheelite during the retrograde stage (300 °C) of the hydrothermal event. During fracture sealing, fluid flux was periodically restricted at the lower D3 thrust. Cycles of high and low up-flow, represented by juvenile H2O-CO2 and evolved H2O-CO2-CH4 fluid, respectively, are recorded by the REE and Sr isotope compositions of scheelite oscillatory zones. The temperature gradient measured in the vein stockwork points to a hot (>600 °C) fluid source 2-4 km below the mine workings, and several kilometres above the base of the greenstone belt. Mass balance calculations involving bulk ore indicate enrichment of both felsic (K, Rb, Cs, Li, Ba, W) and mafic elements (Ca, Sr, Mg, Ni, V, Cr, Te), a source signature compatible with the local high-Mg porphyry suite but not with the meta-gabbro host rock. The initial 87Sr/86Sr ratios of the vein scheelites (0.7014-0.7016) are higher than the mantle ratio of the meta-gabbro (0.7009-0.7011) and overlap those of high-Mg monzodiorite intrusions (0.7016-0.7018) emplaced along the Golden Mile Fault at 2,662 ± 6 Ma to 2,658 ± 3 Ma.

  10. Interacting Jets from Binary Protostars

    E-print Network

    G. C. Murphy; T. Lery; S. O'Sullivan; D. Spicer; F. Bacciotti; A. Rosen

    2007-11-20

    We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and jets. However, binary jets have only been observed in a very small number of systems. We model numerically 3D binary jets for various outflow parameters. We also model the propagation of jets from a specific source, namely L1551 IRS 5, known to have two jets, using recent observations as constraints for simulations with a new MHD code. We examine their morphology and dynamics, and produce synthetic emission maps. We find that the two jets interfere up to the stage where one of them is almost destroyed or engulfed into the second one. We are able to reproduce some of the observational features of L1551 such as the bending of the secondary jet. While the effects of orbital motion are negligible over the jets dynamical timeline, their interaction has significant impact on their morphology. If the jets are not strictly parallel, as in most observed cases, we show that the magnetic field can help the collimation and refocusing of both of the two jets.

  11. Jet propagation through energetic materials

    SciTech Connect

    Pincosy, P; Poulsen, P

    2004-01-08

    In applications where jets propagate through energetic materials, they have been observed to become sufficiently perturbed to reduce their ability to effectively penetrate subsequent material. Analytical calculations of the jet Bernoulli flow provides an estimate of the onset and extent of such perturbations. Although two-dimensional calculations show the back-flow interaction pressure pulses, the symmetry dictates that the flow remains axial. In three dimensions the same pressure impulses can be asymmetrical if the jet is asymmetrical. The 3D calculations thus show parts of the jet having a significant component of radial velocity. On the average the downstream effects of this radial flow can be estimated and calculated by a 2D code by applying a symmetrical radial component to the jet at the appropriate position as the jet propagates through the energetic material. We have calculated the 3D propagation of a radio graphed TOW2 jet with measured variations in straightness and diameter. The resultant three-dimensional perturbations on the jet result in radial flow, which eventually tears apart the coherent jet flow. This calculated jet is compared with jet radiographs after passage through the energetic material for various material thickness and plate thicknesses. We noted that confinement due to a bounding metal plate on the energetic material extends the pressure duration and extent of the perturbation.

  12. SIMULATION AND MOCKUP OF SNS JET-FLOW TARGET WITH WALL JET FOR CAVITATION DAMAGE MITIGATION

    SciTech Connect

    Wendel, Mark W [ORNL; Geoghegan, Patrick J [ORNL; Felde, David K [ORNL

    2014-01-01

    Pressure waves created in liquid mercury pulsed spallation targets at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory induce cavitation damage on the stainless steel target container. The cavitation damage is thought to limit the lifetime of the target for power levels at and above 1 MW. Severe through-wall cavitation damage on an internal wall near the beam entrance window has been observed in spent-targets. Surprisingly though, there is very little damage on the walls that bound an annular mercury channel that wraps around the front and outside of the target. The mercury flow through this channel is characterized by smooth, attached streamlines. One theory to explain this lack of damage is that the uni-directional flow biases the direction of the collapsing cavitation bubble, reducing the impact pressure and subsequent damage. The theory has been reinforced by in-beam separate effects data. For this reason, a second-generation SNS mercury target has been designed with an internal wall jet configuration intended to protect the concave wall where damage has been observed. The wall jet mimics the annular flow channel streamlines, but since the jet is bounded on only one side, the momentum is gradually diffused by the bulk flow interactions as it progresses around the cicular path of the target nose. Numerical simulations of the flow through this jet-flow target have been completed, and a water loop has been assembled with a transparent test target in order to visualize and measure the flow field. This paper presents the wall jet simulation results, as well as early experimental data from the test loop.

  13. Double-focusing mixing jet for XFEL study of chemical kinetics

    PubMed Central

    Wang, Dingjie; Weierstall, Uwe; Pollack, Lois; Spence, John

    2014-01-01

    Several liquid sample injection methods have been developed to satisfy the requirements for serial femtosecond X-ray nanocrystallography, which enables radiation-damage-free determination of molecular structure at room temperature. Time-resolved nanocrystallography would combine structure analysis with chemical kinetics by determining the structures of the transient states and chemical kinetic mechanisms simultaneously. A windowless liquid mixing jet device has been designed for this purpose. It achieves fast uniform mixing of substrates and enzymes in the jet within 250?µs, with an adjustable delay between mixing and probing by the X-ray free-electron laser beam of up to 1?s for each frame of a ‘movie’. The principle of the liquid mixing jet device is illustrated using numerical simulation, and experimental results are presented using a fluorescent dye. PMID:25343806

  14. Double-focusing mixing jet for XFEL study of chemical kinetics.

    PubMed

    Wang, Dingjie; Weierstall, Uwe; Pollack, Lois; Spence, John

    2014-11-01

    Several liquid sample injection methods have been developed to satisfy the requirements for serial femtosecond X-ray nanocrystallography, which enables radiation-damage-free determination of molecular structure at room temperature. Time-resolved nanocrystallography would combine structure analysis with chemical kinetics by determining the structures of the transient states and chemical kinetic mechanisms simultaneously. A windowless liquid mixing jet device has been designed for this purpose. It achieves fast uniform mixing of substrates and enzymes in the jet within 250?µs, with an adjustable delay between mixing and probing by the X-ray free-electron laser beam of up to 1?s for each frame of a `movie'. The principle of the liquid mixing jet device is illustrated using numerical simulation, and experimental results are presented using a fluorescent dye. PMID:25343806

  15. Liquid pearls

    E-print Network

    Bremond, Nicolas; Bibette, Jérôme

    2010-01-01

    This fluid dynamics video reports how to form liquid core capsules having a thin hydrogel elastic membrane named liquid pearls. These fish-egg like structures are initially made of a millimetric liquid drop, aqueous or not, coated with an aqueous liquid film containing sodium alginate that gels once the double drop enters a calcium chloride bath. The creation of such pearls with micrometer thick membrane requires to suppress mixing until gelling takes place. Here, we show that superimposing a two dimensional surfactant precipitation at the interface confers a transient rigidity that can damp the shear induced instability at impact. Based on this, pearls containing almost any type of liquids can be created. The video focuses on the dynamics of the entry of the compound drop into the gelling bath.

  16. A Computational and Experimental Investigation of Shear Coaxial Jet Atomization

    NASA Technical Reports Server (NTRS)

    Ibrahim, Essam A.; Kenny, R. Jeremy; Walker, Nathan B.

    2006-01-01

    The instability and subsequent atomization of a viscous liquid jet emanated into a high-pressure gaseous surrounding is studied both computationally and experimentally. Liquid water issued into nitrogen gas at elevated pressures is used to simulate the flow conditions in a coaxial shear injector element relevant to liquid propellant rocket engines. The theoretical analysis is based on a simplified mathematical formulation of the continuity and momentum equations in their conservative form. Numerical solutions of the governing equations subject to appropriate initial and boundary conditions are obtained via a robust finite difference scheme. The computations yield real-time evolution and subsequent breakup characteristics of the liquid jet. The experimental investigation utilizes a digital imaging technique to measure resultant drop sizes. Data were collected for liquid Reynolds number between 2,500 and 25,000, aerodynamic Weber number range of 50-500 and ambient gas pressures from 150 to 1200 psia. Comparison of the model predictions and experimental data for drop sizes at gas pressures of 150 and 300 psia reveal satisfactory agreement particularly for lower values of investigated Weber number. The present model is intended as a component of a practical tool to facilitate design and optimization of coaxial shear atomizers.

  17. Experiments in axisymmetric supersonic jets

    NASA Astrophysics Data System (ADS)

    Moore, Cyrille Dennis

    An experimental study of the effects of exit Mach number and density ratio on the development of axisymmetric jets is described in this thesis. Jet exit Mach numbers of 1.41, 2.0, and 3.0, were studied for jets of helium, argon, and nitrogen. The jets exit into a gas at rest (velocity ratio = 0), in order to better isolate the effects of compressibility and density ratio. Density ratios vary from 0.23 to 5.5.In order to generate shock free-jets, unique nozzles were designed and constructed for each gas and Mach number combination. A plating method for the construction of the nozzles was developed to ensure high-accuracy and a good surface finish at a cost significantly less than direct-machining techniques.The spreading rate of the jet for several downstream locations is measured with a pitot probe. Centerline data are used to characterise the length of the potential core of the jet, which correlates well with the relative spreading rates. Limited frequency data is obtained through the use of piezo-resistive pressure probes. This method is promising for flows that are not conducive to hot-wire probes.Spark shadography is used to visualize both the mean and instantaneous flow, with the minimum spark time being 20 nanoseconds. The convection velocity of large-scale disturbances is estimated from the visible Mach-type acoustic waves emanating from the jet.For a wide range of jet Mach and Reynolds numbers, the convection velocity of the large scale disturbances in the potential core region of the jet is approximately 0.8 times the jet velocity, the approximate velocity of the first helical instability mode of the jet.The main objectives of the present work were to investigate the effects of compressibility and density on the initial development of the axisymmetric jet. Although the data are not sufficient to determine if the convective Mach number concept used in 2-d shear layer research will work in the case of an axisymmetric jet, it is clear that the axisymmetric data do not collapse onto the 2-d curve. However, the density ratio scaling used for the 2-d shear layer appears to work well for the axisymmetric jet, based on the available data.The data appear to indicate that the initial development of the jet is dominated by instability modes of the jet as a whole, rather than the shear layers.One anomaly noted was that there were long period variations in the centerline total pressure, with times on the order of 3000 jet time scales. The fluctuations did not appear to be experimental artifacts.

  18. Experimental studies of unbiased gluon jets from e^+e^? annihilations using the jet boost algorithm

    E-print Network

    Wilson, Graham Wallace; Abbiendi, G.; Ainsley, C.; Å kesson, P. F.; Alexander, G.; Allison, J.; Amaral, P.; Anagnostou, G.; Anderson, K. J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.

    2004-02-25

    We present the first experimental results based on the jet boost algorithm, a technique to select unbiased samples of gluon jets in e^+e^? annihilations, i.e. gluon jets free of biases introduced by event selection or jet ...

  19. Interfacial deformation and jetting of a magnetic fluid

    E-print Network

    Afkhami, Shahriar; Griffiths, Ian M

    2015-01-01

    An attractive technique for forming and collecting aggregates of magnetic material at a liquid--air interface by an applied magnetic field gradient was recently addressed theoretically and experimentally [Soft Matter, (9) 2013, 8600-8608]: when the magnetic field is weak, the deflection of the liquid--air interface has a steady shape, while for sufficiently strong fields, the interface destabilizes and forms a jet that extracts magnetic material. Motivated by this work, we develop a numerical model for the closely related problem of solving two-phase Navier--Stokes equations coupled with the static Maxwell equations. We computationally model the forces generated by a magnetic field gradient produced by a permanent magnet and so determine the interfacial deflection of a magnetic fluid (a pure ferrofluid system) and the transition into a jet. We analyze the shape of the liquid--air interface during the deformation stage and the critical magnet distance for which the static interface transitions into a jet. We d...

  20. Study of Slanted Perforated Jets

    NASA Astrophysics Data System (ADS)

    Ahmed, R. Asad; Thanigaiarasu, S.; Santhosh, J.; Elangovan, S.; Rathakrishnan, E.

    2013-12-01

    This paper presents the numerical simulation of the subsonic jets controlled by slanted perforated tabs and its performance of mixing efficiency is compared with the jet controlled by solid tab and free jet. The objective of this paper is to study the performance of slanted perforation geometry tabs in controlling high speed jets to enhance the mixing of jet with the ambient air, to suppress the noise level and to minimize the thrust loss. In this paper the simulations have been carried out using the commercial meshing and analysis software. Due to the effect of tabs the potential core decay occurs and velocity reduces drastically because of enhanced mixing produced by the tabs. From the results it is found that in slanted perforated tab the main jet interacts with the slanted perforated jet which causes in effective mixing, instability in jets and lower thrust loss when compared with the free jet. The decay of the potential core and velocity reduction is computed by simulation for 0.4 Mach number. Velocity plots are obtained at both near field and far field downstream locations to study the jet distortion with slanted perforated tabs and solid tabs. The results obtained for perforated tabs for 0.4 Mach number are also compared with various other Mach numbers. They have also been validated with experimental results which show good agreement with the computational results.

  1. Visualization of tabbed sonic jets

    NASA Astrophysics Data System (ADS)

    Clement, Shibu; Rathakrishnan, Ethirajan

    2005-03-01

    This work aims at understanding the physics governing the effect of mechanical tabs on the vortical structures in the near field of jet mixing region. Jets from a sonic nozzle with and without tabs operated at nozzle pressure ratios from 2 to 7 were studied in the present investigation. Tabs with various combinations of length to width ratios were investigated by keeping the blockage area constant. The tabs offered a blockage of 10.18 percent of nozzle exit area. It was found that when the tabs are introduced, two pairs of counter rotating streamwise vortices are shed all along the edges of the tabs and these vortices act as effective mixing promoters. It is evident from centerline pitot pressure decay that, for the tabbed jet a maximum core reduction of 75% was achieved for NPR 7 compared to uncontrolled jet. Direct shadowgraph technique was employed to capture the waves in the controlled and uncontrolled jets. It showed that the tabs are effective in weakening the shock structure in the jet core. To gain an insight into the jets spread rate and the distortion of tabbed jets a surface flow visualization method was developed and employed. Presence of two pairs of streamwise vortices in the vicinity of nozzle exit and the bifurcation of the jet field at the downstream for the tabbed jets were also captured by the surface coating technique.

  2. Experimental modeling of jet-ring turbine disk cooling

    NASA Technical Reports Server (NTRS)

    Metzger, D. E.; Kim, Y. W.

    1991-01-01

    The experimental facility and some early results are described from a current research program modeling turbine disk cooling with multiple impinging jets, such as employed on the Space Shuttle Main Engine oxygen turbopump. The study is designed to obtain detailed local convection heat transfer rates on specially constructed turbine disk models that employ either multiple cooling jet impingement near the disk outer radius from a jet ring, or alternatively, single entrance coolant supply into the center of the disk cavity. Jet impingement is an effective scheme for cooling of turbine disks at or near the blade attachment region, but the heat transfer mechanisms and merits relative to other schemes are not well understood. The present study employs two specially constructed full scale plastic model disks, contoured and plane, together with the corresponding stators. Local heat transfer rates are determined by a computer vision system from the response of thin liquid crystal coatings applied to the disk test faces. The present results indicate that multiple jet impingement directed at the blade attachment region results in higher cooling rates in that region than does the same flow supplied to the disk center, but this conclusion must be regarded as tentative.

  3. Formation of jets and water clouds on Jupiter

    NASA Astrophysics Data System (ADS)

    Lian, Y.; Showman, A. P.

    2012-12-01

    Ground-based and spacecraft observations show that Jupiter exhibits multiple banded zonal jet structures. These banded jets correlate with dark and bright clouds, often called "belts" and "zones". The mechanisms that produce these banded zonal jets and clouds are poorly understood. Our previous studies showed that the latent heat released by condensation of water vapor could produce equatorial superrotation along with multiple zonal jets in the mid-to-high latitudes. However, that previous work assumed complete and instant removal of condensate and therefore could not predict the cloud formation. Here we present an improved 3D Jupiter model to investigate some effects of cloud microphysics on large-scale dynamics using a closed water cycle that includes condensation, three-dimensional advection of cloud material by the large-scale circulation, evaporation and sedimentation. We use a simplified Betts-Miller scheme to relax the temperature and water vapor towards moist adiabat and saturation profile respectively when atmospheric columns become conditionally unstable, and apply a dry convective adjustment scheme in region deeper than the cloud base to mix heat and tracers. We further assume that the liquid particles are well mixed within the clouds during condensation. Other physics parameterizations included in our model are the bottom drag and internal heat flux as well as the Newtonian heating. We find that the active water cycle can produce numerous convective storms and multiple banded jets with equatorial superrotation. However the clouds are sporadic and not coherent with the jet structures. Here we will discuss the jet-forming mechanism compared to our previous studies and cloud morphologies under the influence of large-scale dynamics.

  4. Modified shielding jet model for twin-jet shielding analysis 

    E-print Network

    Gilbride, Jennifer Frances

    1983-01-01

    aircraft noise level, but also indicates the possibility of jet engine installation as a means of The format of this paper follows the style of the "Journal of Heat Transfer" aircraft noise control. For instance, an ovezwing, underwing configuration... August 1983 Major Subject: Mechanical Engineering MODIFIED SHIELDING JET MODEL FOR TWIN-JET SHIELDING ANALYSIS A Thesis by JENNIFER FRANCES GILBRIDE Approved as to stvle and content by: 'Carl H. Gerhold (Chairman of Committee) J. Craag Dutton...

  5. Overcoming Jet Lag

    PubMed Central

    Cornelson, Brian M.

    1985-01-01

    Jet lag is a symptom complex resulting from travel across time zones, which can incapacitate travellers for several days. It is a result of the abrupt changes forced on travellers' sense of time, place and wellbeing, and on their internal cycles. It is manifested in its early phase by exhaustion out of proportion to the length of the flight, disorientation to time, and disruption in sense of wellbeing, memory and performance. In the later phase, profound exhaustion, constipation or diarrhea, anorexia, insomnia, headache, and limited night and peripheral vision may be experienced. Light, food, methylated xanthines (coffee, tea, etc.), physical and mental activity, alcohol and smoking affect bodily rhythms. Awareness and manipulation of these ‘cues’ before, during and after a flight can significantly reduce jet lag. PMID:21274126

  6. Synthetic Jet Propulsion for Small Underwater Vehicles

    Microsoft Academic Search

    Annmarie Polsenberg Thomas; Michele Milano; Maxwell Grazier G'sell; Kathleen Fischer; Joel W. Burdick

    2005-01-01

    This paper proposes a new synthetic jet actuation concept for small, low speed, highly maneuverable AUVs. Synthetic jet thrusters, which produce jets of vortex rings, are inspired by the pulsatile jet propulsion of salps, jellyfish, and squid. To assess the potential utility of this scheme, we developed synthetic jet actuator prototypes, and verified their function via both force measurement and

  7. Micromachined chemical jet dispenser

    SciTech Connect

    Swierkowski, S.; Ciarlo, D.

    1996-05-13

    Goal is to develop a multi-channel micromachined chemical fluid jet dispenser that is applicable to prototype tests with biological samples that demonstrate its utility for molecular biology experiments. Objective is to demonstrate a new device capable of ultrasonically ejecting droplets from 10-200 {mu}m diameter capillaries that are arranged in an array that is linear or focused. The device is based on several common fabrication procedures used in MEMS (micro electro mechanical systems) technology: piezoelectric actuators, silicon, etc.

  8. The Jet Metric

    Microsoft Academic Search

    Marco Loog

    2007-01-01

    In order to define a metric on jet space, linear scale space is considered from a statistical standpoint. Given a scale ?, the scale space solution can be interpreted as maximizing a certain Gaussian posterior probability, related to a particular\\u000a Tikhonov regularization. The Gaussian prior, which governs this solution, in fact induces a Mahalanobis distance on the space\\u000a of functions.

  9. Magnetic reconnection acceleration of astrophysical jets for different jet geometries

    NASA Astrophysics Data System (ADS)

    Chen, A.-Ming; Rui, Li-Ming

    2015-04-01

    The acceleration mechanisms of relativistic jets are of great importance for understanding various astrophysical phenomena such as gamma-ray bursts, active galactic nuclei and microquasars. One of the most popular scenarios is that the jets are initially Poynting-flux dominated and succumb to magnetohydrodynamic instability leading to magnetic reconnections. We suggest that the reconnection timescale and efficiency could strongly depend on the geometry of the jet, which determines the length scale on which the orientations of the field lines change. In contrast to a usually-assumed conical jet, the acceleration of a collimated jet can be found to be more rapid and efficient (i.e. a much more highly saturated Lorentz factor can be reached) while the jets with lateral expansion show the opposite behavior. The shape of the jet could be formed due to the lateral squeezing on the jet by the stellar envelope of a collapsing massive star or the interaction of the jet with stellar winds. Supported by the National Natural Science Foundation of China.

  10. Three-dimensional interactions of a free jet with a perpendicular synthetic jet

    Microsoft Academic Search

    David A. Tamburello; Michael Amitay

    2007-01-01

    Three-dimensional interaction of an axisymmetric free jet with a single synthetic jet that is oriented perpendicular to the free jet was investigated experimentally using PIV. The main objective was to investigate the effect of the upstream location of the synthetic jet, inside the nozzle of the main jet (ReUe = 6600). The interaction location of the synthetic jet (for a

  11. Exploring Liquids

    NSDL National Science Digital Library

    2012-06-26

    Young learners investigate and observe the properties of three liquids -- water, vegetable oil, and corn syrup. They use their senses to collect data and ask and answer questions. This lesson for young learners introduces the scientific process.

  12. Wave Modes in Collapsar Jets

    E-print Network

    E. A. Gomez; P. E. Hardee

    2003-11-05

    Collapsars may be a source for the long Gamma Ray Bursts (GRBs) in the BATSE catalog. Collapsars may radiate gamma rays anisotropically by beamed jet emission close to the observer's line of sight. These jets must penetrate the radiation-dominated medium of their collapsar progenitor and break through its atmosphere in order to produce a GRB. We present a study of previously published, axisymmetric, collapsar jet simulations. Here we use the linearized, relativistic fluid equations to find the Kelvin-Helmholtz modes that are triggered by recollimation shocks within the jet. The modes will grow as they propagate with the jet. These are of interest since the light curves of GRBs show evidence of a variable flow from the GRB engine. We also evaluate effects of grid scaling in the numerical simulation and show that short wavelength modes are suppressed by grid scaling before the jet breaks out of the Helium shell.

  13. Investigation of Dynamic Oxygen Adsorption in Molten Solder Jetting Technology

    NASA Technical Reports Server (NTRS)

    Megaridis, Constantine M.; Bellizia, Giulio; McNallan, Michael; Wallace, David B.

    2003-01-01

    Surface tension forces play a critical role in fluid dynamic phenomena that are important in materials processing. The surface tension of liquid metals has been shown to be very susceptible to small amounts of adsorbed oxygen. Consequently, the kinetics of oxygen adsorption can influence the capillary breakup of liquid-metal jets targeted for use in electronics assembly applications, where low-melting-point metals (such as tin-containing solders) are utilized as an attachment material for mounting of electronic components to substrates. By interpreting values of surface tension measured at various surface ages, adsorption and diffusion rates of oxygen on the surface of the melt can be estimated. This research program investigates the adsorption kinetics of oxygen on the surface of an atomizing molten-metal jet. A novel oscillating capillary jet method has been developed for the measurement of dynamic surface tension of liquids, and in particular, metal melts which are susceptible to rapid surface degradation caused by oxygen adsorption. The experimental technique captures the evolution of jet swells and necks continuously along the jet propagation axis and is used in conjunction with an existing linear, axisymmetric, constant-property model to determine the variation of the instability growth rate, and, in turn, surface tension of the liquid as a function of surface age measured from the exit orifice. The conditions investigated so far focus on a time window of 2-4ms from the jet orifice. The surface properties of the eutectic 63%Sn-37%Pb solder alloy have been investigated in terms of their variation due to O2 adsorption from a N2 atmosphere containing controlled amounts of oxygen (from 8 ppm to 1000 ppm). The method performed well for situations where the oxygen adsorption was low in that time window. The value of surface tension for the 63Sn-37Pb solder in pure nitrogen was found to be 0.49 N/m, in good agreement with previously published work. A characteristic time of O(1ms) or less was determined for the molten-metal surface to be saturated by oxygen at 1000 ppm concentration in N2.

  14. [Pelletization of melts and liquids].

    PubMed

    Rabisková, Miloslava

    2011-04-01

    During the second half of the last century, pelletization methods based on wetting were developed, e.g. agglomeration in coating pans, pelletization plates or fluid-bed equipment, layering of the drug in solution or suspension on inactive spherical cores, extrusion/spheronization and later on also rotoagglomeration in rotogranulators or rotoprocessors. These technologies have become a requisite part of industrial production of solid dosage forms. At present, numerous experimental papers deal with pellet preparation from melts and liquids. These new pelletization methods are the topic of the present article. Pellet preparation from melts is represented by three methods, i.e. fluid hot melt agglomeration, hot melt extrusion, and freeze pelletization. Jet cutting and cryopelletization are the techniques dealing with pellet preparation from liquids. PMID:21650006

  15. Illinois Team Advances Resolution of E-Jet Printing Staff --Semiconductor International, 9/6/2007 2:40:00 PM

    E-print Network

    Rogers, John A.

    Illinois Team Advances Resolution of E-Jet Printing Staff -- Semiconductor International, 9 that they have improved e-jet printing, which is used to create large-area circuits, displays and photovoltaic printing processes can produce "functional devices that establish new resolution benchmarks for liquid

  16. Jet Formation and Collimation

    NASA Astrophysics Data System (ADS)

    Sauty, Christophe; Tsinganos, Kanaris; Trussoni, Edoardo

    We briefly review our current understanding for the formation, acceleration and collimation of winds to jets associated with compact astrophysical objects such as AGN and µQuasars.All such outflows may be considered to a first approximation as ideal MHD plasmas escaping from a rotating and magnetized accretion disk with a magnetosphere around a central black hole. A crucial ingredient for a correct modelling of the steady state problem is to place the appropriate boundary conditions, by taking into account how information can propagate through the outflow and ensuring, e.g., that shocks produced via the interaction of the flow with the external medium do not affect the overall structure. As an example underlining the role of setting the correct boundary conditions, we make the analogy of the critical surfaces in the steady and axisymmetric MHD problem with the event horizon and ergosphere of a rotating black hole in relativity.We discuss the acceleration of the outflow, by gas, radiation, or wave pressure gradients and also by magnetic mechanisms, showing the important role played by the disk corona in the vicinity of the black hole. Pressure and magnetic confinement both may also play a role in confining the outflow, although magnetic hoop stress confinement is likely to be a rather dominant process in tightly collimated outflows. The possible asymptotical morphology that jets achieve and the instabilities which are likely to explain the observed structures but do not prevent jets to possess toroidal magnetic fields are also reviewed.Finally, it is proposed that in a space where the two main variables are the energy of the magnetic rotator and the angle between the line of sight and the ejection axis, some observed characteristics of AGN jets can be understood. A criterion for the transition of the morphologies of the outflows from highly collimated jets to uncollimated winds is given. It is based on the analysis of a particular class of exact solutions and may somehow generalize other earlier suggestions, such as the spinning of the black hole, the fueling of the central object, or the effects of the environment.Thus, while the horizontal AGN classification from Type 0 to Types 1 and 2 may well be an orientation effect - i.e. a dependence on the viewing angle between the source axis and the observer as in the standard model - the vertical AGN classification with uncollimated outflows (radio-quiet sources) and collimated outflows (radio-loud sources) depends both on the efficiency of the magnetic rotator and the environment in which the outflows propagate.

  17. Thermal Radiation from GRB Jets

    Microsoft Academic Search

    Akira Mizuta; Shigehiro Nagataki; Junichi Aoi

    2010-01-01

    In this study, the light curves and spectrum of the photospheric thermal\\u000aradiation from ultrarelativistic gamma-ray burst (GRB) jets are calculated\\u000ausing 2D relativistic hydrodynamic simulations of jets from a collapsar. As the\\u000ajet advances, the density around the head of the jet decreases, and its Lorentz\\u000afactor reaches as high as 200 at the photosphere and 400 inside the

  18. Impeller for Water Jet Propulsion

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Marshall Space Flight Center engineers helped North American Marine Jet (NAMJ), Inc. improve the proposed design of a new impeller for jet propulsion system. With a three-dimensional computer model of the new marine jet engine blades, engineers were able to quickly create a solid ploycarbonate model of it. The rapid prototyping allowed the company to avoid many time-consuming and costly steps in creating the impeller.

  19. Macroscopic analysis of gas-jet wiping: Numerical simulation and experimental approach

    NASA Astrophysics Data System (ADS)

    Lacanette, Delphine; Gosset, Anne; Vincent, Stéphane; Buchlin, Jean-Marie; Arquis, Éric

    2006-04-01

    Coating techniques are frequently used in industrial processes such as paper manufacturing, wire sleeving, and in the iron and steel industry. Depending on the application considered, the thickness of the resulting substrate is controlled by mechanical (scraper), electromagnetic (if the entrained fluid is appropriated), or hydrodynamic (gas-jet wiping) operations. This paper deals with the latter process, referred to as gas-jet wiping, in which a turbulent slot jet is used to wipe the coating film dragged by a moving substrate. This mechanism relies on the gas-jet-liquid film interaction taking place on the moving surface. The aim of this study is to compare the results obtained by a lubrication one-dimensional model, numerical volume of fluid-large eddy simulation (VOF-LES) modeling and an experimental approach. The investigation emphasizes the effect of the controlling wiping parameters, i.e., the pressure gradient and shear stress distributions induced by the jet, on the shape of the liquid film. Those profiles obtained experimentally and numerically for a jet impinging on a dry fixed surface are compared. The effect of the substrate motion and the presence of the dragged liquid film on these actuators are analyzed through numerical simulations. Good agreement is found between the film thickness profile in the wiping zone obtained from the VOF-LES simulations and with the analytical model, provided that a good model for the wiping actuators is used. The effect of the gas-jet nozzle to substrate standoff distance on the final coating thickness is analyzed; the experimental and predicted values are compared for a wide set of conditions. Finally, the occurrence of the splashing phenomenon, which is characterized by the ejection of droplets from the runback film flow at jet impingement, thus limiting the wiping process, is investigated through experiments and numerical simulations.

  20. Thick liquid protection in inertial fusion power plants

    NASA Astrophysics Data System (ADS)

    Pemberton, Steven James

    Liquid jets are designed and developed for the construction of a thick-liquid first wall in fusion power plants, with attention to preventing line-of-sight interaction between target debris and solid structural materials in inertial fusion power plants. First, an introduction is given to basic fusion concepts in order to set the background for inertial fusion plant design. After this introduction, scaling relationships for experimental studies are presented and different jet types for thick-liquid inertial fusion chambers are described, including stationary cylindrical jet grids, large oscillating liquid slabs, and vortex tubes created from centrifugal flow inside pipes. The design of vortex tubes is given in some detail with an illustration of some simple concepts from fluid mechanics for the evolution of flow in the tubes, and the results of this basic analysis are compared to empirical results from a prototype device. The actual thickness of the vortex layer is found to depart from the ideal, laminar consideration of the flow development. However, the basic considerations also predict that flow in the vortex layer will remain stable in the region of interest, and will be independent of the volumetric flow rate. These estimates are supported by experimental observations. The construction of a prototype slab jet is also described, and one chapter of this dissertation is dedicated to the analysis of impulse delivery to and dispersion within a slab jet with finely dispersed voids. The reaction of a slab jet to impulse loading is predicted using a simple compressible flow model for incompressible fluid with dispersed voids. The model is compared with experimental impulse-load data, and it is found that this simple model does a fair job of predicting the empirical results. The dissertation concludes with a discussion of some important factors in vortex flow and slab jet disruption, and possible sources of departure from the basic analyses.

  1. Jet Physics at the Tevatron

    SciTech Connect

    Bhatti, Anwar; Lincoln, Don

    2010-02-01

    Jets have been used to verify the theory of quantum chromodynamics (QCD), measure the structure of the proton and to search for the physics beyond the Standard Model. In this article, we review the current status of jet physics at the Tevatron, a {radical}s = 1.96 TeV p{bar p} collider at the Fermi National Accelerator Laboratory. We report on recent measurements of the inclusive jet production cross section and the results of searches for physics beyond the Standard Model using jets. Dijet production measurements are also reported.

  2. Electromagnetic Models of Extragalactic Jets

    SciTech Connect

    Lisanti, M.; Blandford, R.; /KIPAC, Menlo Park

    2007-10-22

    Relativistic jets may be confined by large-scale, anisotropic electromagnetic stresses that balance isotropic particle pressure and disordered magnetic field. A class of axisymmetric equilibrium jet models will be described and their radiative properties outlined under simple assumptions. The partition of the jet power between electromagnetic and mechanical forms and the comoving energy density between particles and magnetic field will be discussed. Current carrying jets may be recognized by their polarization patterns. Progress and prospects for measuring this using VLBI and GLAST observations will be summarized.

  3. Dissipationless decay of Jovian jets

    NASA Astrophysics Data System (ADS)

    Pirraglia, J. A.

    1989-05-01

    IRIS data have been taken as the bases of windshear calculations whose results imply a decrease of the Jovian planet's zonal jets with altitude. The simplified dynamical model developed to furnish a mechanism accounting for the decay involves a highly truncated set of dissipationless equations simulating the upper-tropospheric and stratospheric flow. While the model's lower boundary is constrained as a latitudinally periodic set of alternating jets, the upper boundary constraint maintains a constant potential temperature. The small perturbations to which the imposed zonal jets are unstable grow and interact nonlinearly, generating a zonal flow that opposes the imposed one and thereby leading to the apparent decrease of the jets with altitude.

  4. Jet penetration of high explosive

    SciTech Connect

    Poulsen, P

    1999-08-11

    It is found that a transition between two flow patterns takes place in thick HE targets. In this case, the jet will initially propagate into the HE at the same rate as into an inert material of the same density. The part of the jet that has stagnated and is flowing nearly co-axially with the incoming jet (but at a much lower speed) is being forced toward the surface of the incoming jet by the pressure of the reaction products but has not as yet made contact. After it makes contact, both axial and perpendicular momentum transfer takes place between the two jet components. After this transition, a new steady state will develop for the propagating jet, with the unperturbed front of the jet propagating at a slower rate than previously. The perturbed front of the jet is still propagating at or near the original rate, having had relatively little axial momentum exchange. However, it has acquired radial momentum and is spreading out as it is propagating; it is therefore becoming less capable of penetrating downstream targets. It is the unperturbed part of the jet that is capable of penetrating downstream targets. A calculational method for predicting this case is presented in this report.

  5. Liquid metal movement during plasma arc cutting

    SciTech Connect

    Nemchinsky, V.A. [ESAB Group Inc., Florence, SC (United States)

    1996-12-01

    The forces acting on the melt (aerodynamic drag, gravity, viscosity and surface tension) during plasma arc cutting are analyzed. The main forces acting on the melt are believed to be the aerodynamic drag force and surface tension. Estimations show that gravity is significant only for thick metal plates. The equation of motion of the liquid metal is derived. This equation allows the velocity and thickness of the liquid metal inside the cut to be calculated (if the gas flow rate is known). In order to determine the gas flow rate, the heat transfer through the liquid layer should be considered. (The plasma jet heats and melts the solid metal through this layer.) As was shown by Shamblin and Amstead, a thick liquid layer can constitute significant thermal resistance for heat transfer. In order to use the power of the plasma jet efficiently, the liquid layer thickness should not exceed a certain limit. Since the layer thickness decreases as the plasma gas velocity increases, this implies a lower limit to the gas flow rate. It is found that the actual gas flow rates are close to but do not exceed this limit.

  6. Mixing and transient interface condensation of a liquid hydrogen tank

    NASA Technical Reports Server (NTRS)

    Lin, C. S.; Hasan, M. M.; Nyland, T. W.

    1993-01-01

    Experiments were conducted to investigate the effect of axial jet-induced mixing on the pressure reduction of a thermally stratified liquid hydrogen tank. The tank was nearly cylindrical, having a volume of about 0.144 cu m with 0.559 m in diameter and 0.711 m long. A mixer/pump unit, which had a jet nozzle outlet of 0.0221 m in diameter was located 0.178 m from the tank bottom and was installed inside the tank to generate the axial jet mixing and tank fluid circulation. The liquid fill and jet flow rate ranged from 42 to 85 percent (by volume) and 0.409 to 2.43 cu m/hr, respectively. Mixing tests began with the tank pressure ranging from 187.5 to 238.5 kPa at which the thermal stratification results in 4.9 to 6.2 K liquid sub cooling. The mixing time and transient vapor condensation rate at the liquid-vapor interface are determined. Two mixing time correlations, based on the thermal equilibrium and pressure equilibrium, are developed. Both mixing time correlations are expressed as functions of system and buoyancy parameters and compared well with other experimental data. The steady state condensation rate correlation of Sonin et al. based on steam-water data is modified and expressed as a function of jet subcooling. The limited liquid hydrogen data of the present study shows that the modified steady state condensation rate correlation may be used to predict the transient condensation rate in a mixing process if the instantaneous values of jet sub cooling and turbulence intensity at the interface are employed.

  7. The Aeration of Aqueous Solutions with Liquid - Air Inductors.

    NASA Astrophysics Data System (ADS)

    Pearce, Timothy David

    This thesis describes studies of liquid-jet air inductors in which a jet of liquid streaming into an open ended tubular section is used to induce a flow of air so producing a gas-liquid mixture. The properties of the device investigated include its fluid mechanics, cocurrent mass transfer characteristics and mass transfer characteristics when used as a gas disperser into an aeration tank. To characterize the fluid mechanics the inductor was divided into nozzle, throat and diffuser sections: the nozzle produces the liquid jet; the throat is where the liquid mixes with the air; the diffuser enables pressure recovery to take place. The use of nozzle swirlers, which impart angular momentum to the liquid jet, has been investigated as a means of overcoming one of the more difficult aspects of inductor design: the selection of the throat length based on the jet break-up length. A model for the swirler/nozzle combination was developed which enabled the jet break-up length to be predicted and showed it to be independent of the operating conditions. The model showed satisfactory agreement with the experiments. Models were developed for the throat and diffuser fluid mechanics and included friction, gravity and interphase slip between the gas and liquid components. Measurements of friction were performed for three sizes of inductor (nominally 13, 25, and 40 mm) using water at liquid supply pressures between of 35 and 310 kPa and the friction factor was correlated in terms of the inductor size and the gas volume flow fraction. The correlations, combined with the model, facilitate the prediction of gas flows and pressure rises across the inductor. In certain cases errors resulting from the predictions are large and an empirical method of dealing with such cases is presented. Mass transfer in the system as a whole was assessed with the inductor acting as a gas disperser, positioned horizontally at the side of the tank so that the gas-liquid mixture issued from the inductor outlet into the liquid in the tank. The measurements were well correlated in terms of the mixture momentum as it entered the tank.

  8. Asymmetric Supernovae from Magnetocentrifugal Jets

    NASA Astrophysics Data System (ADS)

    Wheeler, J. Craig; Meier, David L.; Wilson, James R.

    2002-04-01

    Strong toroidal magnetic fields generated in stellar collapse can generate magnetocentrifugal jets in analogy to those found in simulations of black hole accretion. Magnetocentrifugal jets may explain why all core collapse supernovae are found to be substantially asymmetric and predominantly bipolar. We describe two phases: the initial LeBlanc-Wilson jet and a subsequent protopulsar or toroidal jet that propagates at about the core escape velocity. The prompt LeBlanc-Wilson jets will produce an excess of neutron-rich matter and hence cannot be the common origin of supernova explosions; similar but less severe problems arise with the protopulsar jet that may be alleviated by partial evacuation along the axis by rotation. The jets will produce bow shocks that tend to expel matter, including iron and silicon, into equatorial tori. This may help to account for observations of the element distribution in Cas A. A magnetic ``switch'' mechanism may apply in rare instances (when there is low density and large magnetic field), with subsequent increase in the speed and collimation of the toroidal jet. The conditions that turn the magnetic switch ``on'' would yield a jet that propagates rapidly and with small opening angle through the star, depositing relatively little momentum. The result could be enough infall to form a black hole. A third, highly relativistic jet from the rotating black hole could catch up to the protopulsar jet after it has emerged from the star. The interaction of these two jets plausibly could be the origin of the internal shocks thought to produce ?-ray bursts and could explain the presence of iron lines in the afterglow. Recent estimates that typical ?-ray burst energy is ~3×1050 ergs imply either a very low efficiency for conversion of rotation into jets by the Blandford-Znajek mechanism or a rather rapid turnoff of the jet process even though the black hole still rotates rapidly. Magnetars and ``hypernovae'' might arise in an intermediate parameter regime of energetic jets that yield larger magnetic fields and provide more energy than the routine case, but that are not so tightly collimated that they yield failed supernova.

  9. Liquid marbles.

    PubMed

    Aussillous, P; Quéré, D

    2001-06-21

    The transport of a small amount of liquid on a solid is not a simple process, owing to the nature of the contact between the two phases. Setting a liquid droplet in motion requires non-negligible forces (because the contact-angle hysteresis generates a force opposing the motion), and often results in the deposition of liquid behind the drop. Different methods of levitation-electrostatic, electromagnetic, acoustic, or even simpler aerodynamic techniques-have been proposed to avoid this wetting problem, but all have proved to be rather cumbersome. Here we propose a simple alternative, which consists of encapsulating an aqueous liquid droplet with a hydrophobic powder. The resulting 'liquid marbles' are found to behave like a soft solid, and show dramatically reduced adhesion to a solid surface. As a result, motion can be generated using gravitational, electrical and magnetic fields. Moreover, because the viscous friction associated with motion is very small, we can achieve quick displacements of the droplets without any leaks. All of these features are of potential benefit in microfluidic applications, and also permit the study of a drop in a non-wetting situation-an issue of renewed interest following the recent achievement of super-hydrophobic substrates. PMID:11418851

  10. Atmospheric Pressure Plasmas Incident onto Thin Liquid Layers

    NASA Astrophysics Data System (ADS)

    Tian, Wei; Norberg, Seth; Babaeva, Natalia Yu.; Kushner, Mark J.

    2013-09-01

    The interaction of plasmas with liquids has increasing importance in advanced manufacturing and biomedical applications. Sustaining atmospheric pressure plasmas on liquids (as opposed to in liquids) can increase the chemical activity of the liquid by transferring more easily produced reactive species from the gas phase into the liquid. Often the intent is to treat the surface under the liquid layer, as in plasma medicine. The liquid then acts as a filter which modifies the fluxes of reactive species prior to reaching the underlying surface. The liquid in turn influences the plasma by evaporation which produces a saturated layer of, for example, water vapor above the liquid surface, or by the shape of liquid covered wounds and the dielectric properties of the liquid. Direct plasma exposure (e.g., a dielectric barrier discharge) enables intersection of ion and UV/VUV fluxes with the liquid surface whereas many remote plasma jets typically do not. This increases the rate of hydronium (H3O+) production which affects pH. In this paper, results from a computational investigation on the dynamics of atmospheric pressure plasmas intersecting thin water layers having dissolved gases and proteins will be discussed. Examples are taken from DBD and plasma jet exposure of water layers over a tissue-like dielectric, and plasmas sustained in bubbles in water. The mutual interaction of the plasma and liquid will be discussed based on radiation and ion transport into the water, evaporation, and transport and conversion of plasma produced reactivity through the water layer. The interaction of plasmas with liquids has increasing importance in advanced manufacturing and biomedical applications. Sustaining atmospheric pressure plasmas on liquids (as opposed to in liquids) can increase the chemical activity of the liquid by transferring more easily produced reactive species from the gas phase into the liquid. Often the intent is to treat the surface under the liquid layer, as in plasma medicine. The liquid then acts as a filter which modifies the fluxes of reactive species prior to reaching the underlying surface. The liquid in turn influences the plasma by evaporation which produces a saturated layer of, for example, water vapor above the liquid surface, or by the shape of liquid covered wounds and the dielectric properties of the liquid. Direct plasma exposure (e.g., a dielectric barrier discharge) enables intersection of ion and UV/VUV fluxes with the liquid surface whereas many remote plasma jets typically do not. This increases the rate of hydronium (H3O+) production which affects pH. In this paper, results from a computational investigation on the dynamics of atmospheric pressure plasmas intersecting thin water layers having dissolved gases and proteins will be discussed. Examples are taken from DBD and plasma jet exposure of water layers over a tissue-like dielectric, and plasmas sustained in bubbles in water. The mutual interaction of the plasma and liquid will be discussed based on radiation and ion transport into the water, evaporation, and transport and conversion of plasma produced reactivity through the water layer. Work supported by DOE Fusion Energy Science and NSF.

  11. The jet impact force of laser-induced bubble under the water-film with different thickness

    NASA Astrophysics Data System (ADS)

    Li, Beibei; Wang, Bingyang; Liu, Xiumei; He, Jie; Lu, Jian

    2015-05-01

    The effect of water-film on the laser-induced bubble was investigated by a piezoelectric ceramic transducer (PZT) sensor. Both of the collapse time and liquid-jet impact force of the bubble under the water-film were obtained, and the experiments were also completed in different laser energy. The collapse time increase with the thickness of the waterfilm, but the liquid-jet impact force decrease. We consider that the collapse time was affected by both of the rigid boundary and surface, and the increasing of the collapse time is the reason the decreasing of the liquid-jet impact force. The velocity of bubble wall is lower with the longer collapse time for the uniform bubbles energy, so the liquid-jet impact force is lower. For the other reasons, more laser energy would be absorbed by the thicker water-film, but the water was also splashed for the thinner water-film. So, for the thinner water-film, the bubble energy is higher, the liquidjet impact force is higher, but the maximal radius is smaller because of the splash process. In the other hand, both of the collapse time and the liquid-jet impact force are increase with the laser energy. These researches are useful for the laser processing under water.

  12. Jam Jar Jet

    NSDL National Science Digital Library

    William Gurstelle

    2011-01-01

    In this activity, learners create a "Jam Jar Jet" based on Francois Reynst's discovery of a pulsejet engine, which uses one opening for both air intake and exhaust. Learners will be amazed at the deep blue, noisy flame that grows and shrinks and "breathes" fire in the jar. Learners can add salt or boric acid crystals to change the color of the flames. Use this activity to explore combustion and/or aerospace engineering. This resource includes step by step instructions with helpful photographs, trouble-shooting tips, and resources. This is an advanced project that should only be undertaken with appropriate safety precautions. Follow all directions carefully.

  13. Visualization of tabbed sonic jets

    Microsoft Academic Search

    Shibu Clement; Ethirajan Rathakrishnan

    2005-01-01

    This work aims at understanding the physics governing the effect of mechanical tabs on the vortical structures in the near field of jet mixing region. Jets from a sonic nozzle with and without tabs operated at nozzle pressure ratios from 2 to 7 were studied in the present investigation. Tabs with various combinations of length to width ratios were investigated

  14. The forced turbulent wall jet

    Microsoft Academic Search

    Y. Katz; E. Horev; I. Wygnanski

    1992-01-01

    Results of an experimental and theoretical investigation of the effects of external 2D excitation on the plane turbulent wall jet are presented. Measurements of the streamwise component of velocity were made throughout the flow field for a variety of imposed frequencies and amplitudes. Two methods of forcing are used: one global, imposed on the entire jet by pressure fluctuations in

  15. JET PROPULSION LABORATORY COVER: FROM

    E-print Network

    Waliser, Duane E.

    4-00 -4-11 5/q'd.... JET PROPULSION LABORATORY 1991 Annual Report #12;COVER: FROM ~IODEST BEGIN Aeronautlcs and Space Adnurustratlon for the peaod January 1 through December 31, 1991. Jet Propulsion Laboratory Cahforrua Instltute ofTechnology Pasadena,~orrua .-. III #12;IINTRODUCTION Propulsion Laboratory

  16. System identification of jet engines

    Microsoft Academic Search

    N. Sugiyama

    2000-01-01

    System identification plays an important role in advanced control systems for jet engines, in which controls are performed adaptively using data from the actual engine and the identified engine. An identification technique for jet engine using the Constant Gain Extended Kalman Filter (CGEKF) is described. The filter is constructed for a two-spool turbofan engine. The CGEKF filter developed here can

  17. Electrohydrodynamic Liquid Disintegration in Micro-, Meso- and Nanoscopic Dimensions

    NASA Astrophysics Data System (ADS)

    Vertes, Akos

    2008-11-01

    The electrohydrodynamic dispersion of liquids spans length scales from 1 mm to 1 nm and involves temporal variations from 1 s to 10 ps. The disintegration mechanisms are diverse and, due to the differences in the dominating forces, vary on the micro-, meso- and nanoscale extending to lower boundaries of 1 ?m, 10 nm and 1 nm, respectively. Using fast imaging, spray current measurements, phase Doppler anemometry and molecular dynamics calculations, we followed the behavior of electrified liquids in the three most common geometries, spherical, pendant drop and slender jet, with dimensions ranging from 100 ?m to 1 nm. Microscale disintegration involves jet ejection from conical surface deformations, jet breakup due to varicose, kink and ramified jet instabilities, and asymmetric droplet fission resulting in side jets. As the liquid dimensions shift from the microscopic dimensions where the processes are governed by the surface tension and the Maxwell stress, to the meso- and nanoscale, thermal fluctuations become increasingly important. The presence of charges in nanodroplets leads to enhanced surface fluctuations, the formation of extreme protrusions and eventually solvated ion evaporation. Charging of slender nanojets results in longer shape relaxation times along with the fission of systems charged below the Rayleigh limit. In collaboration with Jelena Lusic and Peter Nemes, George Washington University.

  18. Multifunctional, three-dimensional tomography for analysis of eletrectrohydrodynamic jetting

    NASA Astrophysics Data System (ADS)

    Nguyen, Xuan Hung; Gim, Yeonghyeon; Ko, Han Seo

    2015-05-01

    A three-dimensional optical tomography technique was developed to reconstruct three-dimensional objects using a set of two-dimensional shadowgraphic images and normal gray images. From three high-speed cameras, which were positioned at an offset angle of 45° between each other, number, size, and location of electrohydrodynamic jets with respect to the nozzle position were analyzed using shadowgraphic tomography employing multiplicative algebraic reconstruction technique (MART). Additionally, a flow field inside a cone-shaped liquid (Taylor cone) induced under an electric field was observed using a simultaneous multiplicative algebraic reconstruction technique (SMART), a tomographic method for reconstructing light intensities of particles, combined with three-dimensional cross-correlation. Various velocity fields of circulating flows inside the cone-shaped liquid caused by various physico-chemical properties of liquid were also investigated.

  19. 3D MHD Jet in a Non-Uniform Magnetic Field

    NASA Astrophysics Data System (ADS)

    Huang, Hulin; Han, Dong

    2005-12-01

    The purpose of this paper is to present a two-phase 3D magnetohydrodynamics (MHD) flow model that combines the volume of fluid (VOF) method with the technique derived from induced-magnetic-field equations for liquid metal free surface MHD-jet-flow. Analogy between the induced-magnetic-filed equation and the conventional computational fluid dynamics (CFD) equation is made, so that the equation can be conveniently accounted for by CFD. A penalty factor numerical method is introduced in order to force the local divergence-free condition of the magnetic fields and an extension of the void insulating calculation domain is applied to ensure that the induced-magnetic field at its boundaries is null. These simulation results for lithium liquid metal jets under magnetic field configurations of Magnetic Torus (Mtor) and National Spherical Torus Experiment (NSTX) outboard divertor have shown that three dimensional jet can not be annihilated by magnetic braking and its cross-section will deform in such a way that the momentum flux of the jet is conserved. 3D MHD effects from a magnetic field gradient cause return currents to interact with applied magnetic fields and produce unfavorable Lorentz forces. Under 3D applied non-uniform magnetic fields of the divertor, unfavorable Lorentz forces lead to a substantial change in flow pattern and a reduction in flow velocity, with the jet cross-section moving to one side of the jet space. These critical phenomena can not be revealed by 2D models.

  20. Assessment of coal liquids as refinery feedstocks

    SciTech Connect

    Zhou, P.

    1992-02-01

    The R&D of direct coal liquefaction has reached such a stage that current two-stage processes can produce coal liquids with high yields and improved quality at a reasonable cost. To fully realize the potential value, these coal liquids should be refined into high-value liquid transportation fuels. The purpose of this study is to assess coal liquids as feedstocks to be processed by modern petroleum refining technologies. After the introduction, Section 2.0 summarizes ASTM specifications for major transportation fuels: gasoline, jet fuel, and diesel fuel, which serve as a target for coal-liquid refining. A concise description of modern refining processes follows with an emphasis on the requirements for the raw materials. These provide criteria to judge the quality of coal liquids as a refinery feedstock for the production of marketable liquid fuels. Section 3.0 surveys the properties of coal liquids produced by various liquefaction processes. Compared with typical petroleum oils, the current two-stage coal liquids are: Light in boiling range and free of resids and metals; very low in sulfur but relatively high in oxygen; relatively low in hydrogen and high in cyclics content; and essentially toxicologically inactive when end point is lower than 650{degrees}F, particularly after hydroprocessing. Despite these characteristics, the coal liquids are basically similar to petroleum. The modern refining technology is capable of processing coal liquids into transportation fuels meeting all specifications, and hydroprocessinq is obviously the major tool. The important point is the determination of a reasonable product slate and an appropriate refining scheme.

  1. Assessment of coal liquids as refinery feedstocks

    SciTech Connect

    Zhou, P.

    1992-02-01

    The R D of direct coal liquefaction has reached such a stage that current two-stage processes can produce coal liquids with high yields and improved quality at a reasonable cost. To fully realize the potential value, these coal liquids should be refined into high-value liquid transportation fuels. The purpose of this study is to assess coal liquids as feedstocks to be processed by modern petroleum refining technologies. After the introduction, Section 2.0 summarizes ASTM specifications for major transportation fuels: gasoline, jet fuel, and diesel fuel, which serve as a target for coal-liquid refining. A concise description of modern refining processes follows with an emphasis on the requirements for the raw materials. These provide criteria to judge the quality of coal liquids as a refinery feedstock for the production of marketable liquid fuels. Section 3.0 surveys the properties of coal liquids produced by various liquefaction processes. Compared with typical petroleum oils, the current two-stage coal liquids are: Light in boiling range and free of resids and metals; very low in sulfur but relatively high in oxygen; relatively low in hydrogen and high in cyclics content; and essentially toxicologically inactive when end point is lower than 650[degrees]F, particularly after hydroprocessing. Despite these characteristics, the coal liquids are basically similar to petroleum. The modern refining technology is capable of processing coal liquids into transportation fuels meeting all specifications, and hydroprocessinq is obviously the major tool. The important point is the determination of a reasonable product slate and an appropriate refining scheme.

  2. Liquid-bubble Interaction under Surf Zone Breaking Waves

    NASA Astrophysics Data System (ADS)

    Derakhti, M.; Kirby, J. T., Jr.

    2014-12-01

    Liquid-bubble interaction, especially in complex two-phase bubbly flow under breaking waves, is still poorly understood. Derakhti and Kirby (2014a,b) have recently studied bubble entrainment and turbulence modulation by dispersed bubbles under isolated unsteady breaking waves along with extensive model verifications and convergence tests. In this presentation, we continue this examination with attention turned to the simulation of periodic surf zone breaking waves. In addition, the relative importance of preferential accumulation of dispersed bubbles in coherent vortex cores is investigated. Heavier-than-liquid particles, i.e. sediment, tend to accumulate in regions of high strain rate and avoid regions of intense vorticity. In contrast, lighter-than-liquid particles such as bubbles tend to congregate in vortical regions. We perform a three dimensional (3D) large-eddy simulation (LES) using a Navier-Stokes solver extended to incorporate entrained bubble populations, using an Eulerian-Eulerian formulation for the polydisperse bubble phase. The volume of fluid (VOF) method is used for free surface tracking. The model accounts for momentum exchange between dispersed bubbles and liquid phase as well as bubble-induced dissipation. We investigate the formation and evolution of breaking-induced turbulent coherent structures (BTCS) under both plunging and spilling periodic breaking waves as well as BTCS's role on the intermittent 3D distributions of bubble void fraction in the surf zone. We particularly examine the correlation between bubble void fractions and Q-criterion values to quantify this interaction. Also, the vertical transport of dispersed bubbles by downburst type coherent structures in the transition region is compared to that by obliquely descending eddies. All the results are summarized at different zones from outer to inner surf zone.

  3. Predicting the liquid flux distribution and collection efficiency in cylindrical Venturi scrubbers

    SciTech Connect

    Ananthanarayanan, N.V.; Viswanathan, S. [National Univ. of Singapore (Singapore). Dept. of Chemical and Environmental Engineering] [National Univ. of Singapore (Singapore). Dept. of Chemical and Environmental Engineering

    1999-01-01

    A simplified two-dimensional model to predict liquid flux distribution and collection efficiency in cylindrical Venturi scrubbers with Pease-Anthony mode operation is evaluated with experimental data from a pilot-scale unit. Prediction of the liquid flux distribution near the point of injection appears to b far from agreement with experimental values while the accuracy of prediction has been found to improve with distance from the injection point. The initial location of the liquid source immediately after atomization has been found to affect the liquid flux distribution significantly. Although the overall liquid distribution pattern is found to be in good agreement with the experimental data, the prediction of liquid distribution appears to be a strong function of jet penetration length and turbulence caused by operating conditions. Concentric injection at high liquid rates could result in collision between jets from nozzles as they converge at the center of the scrubber. Turbulence caused by interaction between the jets is accounted for by using varying Peclet numbers. A dimensionless group, Venturi number, developed from jet penetration correlation has been found to predict conditions that give rise to uniform flux distribution and maximum collection efficiency. Venturi numbers between 1 {times} 10{sup {minus}3} and 1.5 {times} 10{sup {minus}3} appear to predict conditions for cylindrical Venturi scrubbers (with radial injection into the throat using nozzles) for optimal liquid utilization and maximum collection efficiency.

  4. Anionic surfactant remediation of soil columns contaminated by nonaqueous phase liquids

    Microsoft Academic Search

    V. Dwarakanath; K Kostarelos; Gary A Pope; Doug Shotts; William H Wade

    1999-01-01

    A variety of column experiments have been completed for the purpose of selecting and evaluating suitable surfactants for remediation of nonaqueous phase liquids (NAPLs). The various NAPLs tested in the laboratory experiments were tetrachloroethylene (PCE), trichloroethylene (TCE), jet fuel (JP4) and a dense nonaqueous phase liquid from a site at Hill Air Force Base, UT. Both Ottawa sand and Hill

  5. Seeing in Color: Jet Superstructure

    SciTech Connect

    Gallicchio, Jason; Schwartz, Matthew D. [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2010-07-09

    A new class of observables is introduced which aims to characterize the superstructure of an event, that is, features, such as color flow, which are not determined by the jet four-momenta alone. Traditionally, an event is described as having jets which are independent objects; each jet has some energy, size, and possible substructure such as subjets or heavy flavor content. This description discards information connecting the jets to each other, which can be used to determine if the jets came from decay of a color-singlet object, or if they were initiated by quarks or gluons. An example superstructure variable, pull, is presented as a simple handle on color flow. It can be used on an event-by-event basis as a tool for distinguishing previously irreducible backgrounds at the Tevatron and the LHC.

  6. Magnetically driven jets and winds

    NASA Technical Reports Server (NTRS)

    Lovelace, R. V. E.; Berk, H. L.; Contopoulos, J.

    1991-01-01

    Four equations for the origin and propagation of nonrelativistic jets and winds are derived from the basic conservation laws of ideal MHD. The axial current density is negative in the vicinity of the axis and positive at larger radii; there is no net current because this is energetically favored. The magnetic field is essential for the jet solutions in that the zz-component of the magnetic stress acts, in opposition to gravity, to drive matter through the slow magnetosonic critical point. For a representative self-consistent disk/jet solution relevant to a protostellar system, the reaction of the accreted mass expelled in the jets is 0.1, the ratio of the power carried by the jets to the disk luminosity is 0.66, and the ratio of the boundary layer to disk luminosities is less than about 0.13. The star's rotation rate decreases with time even for rotation rates much less than the breakup rate.

  7. Twist in a polar blowout jet

    NASA Astrophysics Data System (ADS)

    Hong, Jun-Chao; Jiang, Yun-Chun; Yang, Jia-Yan; Zheng, Rui-Sheng; Bi, Yi; Li, Hai-Dong; Yang, Bo; Yang, Dan

    2013-03-01

    It is well known that some coronal jets exhibit helical structures and untwisting. We attempt to inspect the origin of twist in a blowout jet. By means of multi-wavelength and multi-angle observations from Solar Dynamics Observatory (SDO) and Solar Terrestrial Relations Observatory-Ahead (STEREO-A), we firstly report a polar untwisting jet that is a blowout jet which leads to a jet-like coronal mass ejection. From the viewpoint of SDO, the jet shows clear untwisting behavior and two jet-spires. However, from the viewpoint of STEREO-A the jet actually comes from the whiplike prominence eruption and is followed by a white-light jet. Our observations indicate that twist in blowout jets may result from the erupting mini-prominences/mini-filaments in the jet base.

  8. Computational Modeling And Analysis Of Synthetic Jets

    NASA Technical Reports Server (NTRS)

    Mittal, Rajat; Cattafesta, Lou

    2005-01-01

    In the last report we focused on the study of 3D synthetic jets of moderate jet aspect-ratio. Jets in quiescent and cross-flow cases were investigated. Since most of the synthetic jets in practical applications are found to be of large aspect ratio, the focus was shifted to studying synthetic jets of large aspect ratio. In the current year, further progress has been made by studying jets of aspect ratio 8 and infinity. Some other aspects of the jet, like the vorticity flux is looked into apart from analyzing the vortex dynamics, velocity profiles and the other dynamical characteristics of the jet which allows us to extract some insight into the effect of these modifications on the jet performance. Also, efforts were made to qualitatively validate the simulated results with the NASA Langley test cases at higher jet Reynolds number for the quiescent jet case.

  9. Comparison of Global Sizing Velocimetry and Phase Doppler Anemometry measurements of alternative jet fuel sprays

    NASA Astrophysics Data System (ADS)

    Sadr, Reza; Kannaiyan, Kumaran

    2013-11-01

    Atomization plays a crucial precursor role in liquid fuel combustion that directly affects the evaporation, mixing, and emission levels. Laser diagnostic techniques are often used to study the spray characteristics of liquid fuels. The objective of this work is to compare the spray measurements of Gas-to Liquid (GTL) jet fuels obtained using Global Sizing Velocimetry (GSV) and Phase Doppler Anemometry (PDA) techniques at global and local levels, respectively. The chemical and physical properties of GTL fuels are different from conventional jet fuels, owing to the difference in their production methodology. In this work, the experimental facility, the measurement techniques, and spray characteristics of two different GTL fuels are discussed and compared with those of Jet A-1 fuel. Results clearly demonstrate that although the global measurement gives an overall picture of the spray, fine details are obtained only through local measurements and complement in gaining more inferences into the spray characteristics. The results also show a close similarity in spray characteristics between GTL and Jet A-1 fuels. Atomization plays a crucial precursor role in liquid fuel combustion that directly affects the evaporation, mixing, and emission levels. Laser diagnostic techniques are often used to study the spray characteristics of liquid fuels. The objective of this work is to compare the spray measurements of Gas-to Liquid (GTL) jet fuels obtained using Global Sizing Velocimetry (GSV) and Phase Doppler Anemometry (PDA) techniques at global and local levels, respectively. The chemical and physical properties of GTL fuels are different from conventional jet fuels, owing to the difference in their production methodology. In this work, the experimental facility, the measurement techniques, and spray characteristics of two different GTL fuels are discussed and compared with those of Jet A-1 fuel. Results clearly demonstrate that although the global measurement gives an overall picture of the spray, fine details are obtained only through local measurements and complement in gaining more inferences into the spray characteristics. The results also show a close similarity in spray characteristics between GTL and Jet A-1 fuels. Funded by Qatar Science and Technology Park.

  10. Study on High Speed Lithium Jet For Neutron Source of Boron Neutron Capture Therapy (BNCT)

    NASA Astrophysics Data System (ADS)

    Takahashi, Minoru; Kobayashi, Tooru; Zhang, Mingguang; Mák, Michael; Štefanica, Jirí; Dostál, Václav; Zhao, Wei

    The feasibility study of a liquid lithium type proton beam target was performed for the neutron source of the boron neutron capture therapy (BNCT). As the candidates of the liquid lithium target, a thin sheet jet and a thin film flow on a concave wall were chosen, and a lithium flow experiment was conducted to investigate the hydrodynamic stability of the targets. The surfaces of the jets and film flows with a thickness of 0.5 mm and a width of 50 mm were observed by means of photography. It has been found that a stable sheet jet and a stable film flow on a concave wall can be formed up to certain velocities by using a straight nozzle and a curved nozzle with the concave wall, respectively.

  11. Prevention of tissue damage by water jet during cavitation Daniel Palanker,a)

    E-print Network

    Palanker, Daniel

    Prevention of tissue damage by water jet during cavitation Daniel Palanker,a) Alexander Vankov Cavitation bubbles accompany explosive vaporization of water following pulsed energy deposition in liquid can produce tissue damage at a distance exceeding the radius of the cavitation bubble by a factor of 4

  12. Evaluation of the Effects of Ink Penetration in Ink Jet Printing: Experiments and Simulation

    Microsoft Academic Search

    Li Yang; Björn Kruse

    In an ink jet printing system consisting of dye-based liquid inks and office copy paper (plain paper), ink penetration has pro- found effects on color rendition. In this report we present methodologies for evaluating these effects by means of experimental data analysis and simulations. On the experimental side, color coordinates of patches printed on two types of substrates, one with

  13. Effect of gluten on soybean oil droplets in jet-cooked starch-oil composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Jet cooked starch-lipid composites have been developed as a technology for suspending micron-size lipid droplets in an aqueous cooked starch dispersion. Normally oil droplets are independent and freely mobile in such liquid composites. When wheat flour was used as the starch source, unusual behavi...

  14. Wheat gluten influences oil droplet size and mobility in jet-cooked starch-oil composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Jet cooked starch-lipid composites have been developed as a technology for suspending micron-size lipid droplets in aqueous cooked starch dispersions. Normally oil droplets are independent and freely mobile in such liquid composites. When wheat flour was used as the starch source, unusual behavior...

  15. Liquid ventilation.

    PubMed

    Sarkar, Suman; Paswan, Anil; Prakas, S

    2014-01-01

    Human have lungs to breathe air and they have no gills to breath liquids like fish. When the surface tension at the air-liquid interface of the lung increases as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV) is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen as the inert carrier of oxygen and carbon dioxide offers a number of advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. It is well-known that respiratory diseases are one of the most common causes of morbidity and mortality in intensive care unit. During the past few years several new modalities of treatment have been introduced. One of them and probably the most fascinating, is of LV. Partial LV, on which much of the existing research has concentrated, requires partial filling of lungs with perfluorocarbons (PFC's) and ventilation with gas tidal volumes using conventional mechanical ventilators. Various physico-chemical properties of PFC's make them the ideal media. It results in a dramatic improvement in lung compliance and oxygenation and decline in mean airway pressure and oxygen requirements. No long-term side-effect reported. PMID:25886321

  16. Layered Liquids

    NSDL National Science Digital Library

    John Eichinger

    2009-05-30

    This activity involves an exploration of density. Why does oil float on water? How does drain cleaner sink down into the clogged pipe right through standing water? These questions will be answered as students make a layered "parfait" of colored liquids ba

  17. Mixing and transient interface condensation of a liquid hydrogen tank

    NASA Technical Reports Server (NTRS)

    Lin, C. S.; Hasan, M. M.; Nyland, T. W.

    1993-01-01

    Experiments were conducted to investigate the effect of axial jet-induced mixing on the pressure reduction of a thermally stratified liquid hydrogen tank. The tank was nearly cylindrical, having a volume of about 0.144 cu m with 0.559 m in diameter and 0.711 m length. A mixer/pump unit, which had a jet nozzle outlet of 0.0221 m in diameter was located 0.178 m from the tank bottom and was installed inside the tank to generate the axial jet mixing and tank fluid circulation. Mixing tests began with the tank pressures at which the thermal stratification results in 4.9-6.2 K liquid subcooling. The mixing time and transient vapor condensation rate at the liquid-vapor interface are determined. Two mixing time correlations, based on the thermal equilibrium and pressure equilibrium, are developed and expressed as functions of system and buoyancy parameters. The limited liquid hydrogen data of the present study shows that the modified steady state condensation rate correlation may be used to predict the transient condensation rate in a mixing process if the instantaneous values of jet sub cooling and turbulence intensity at the interface are employed.

  18. Liquid Ropes: A Geometrical Model for Thin Viscous Jet Instabilities

    E-print Network

    Brun, P.-T.; Audoly, Basile; Ribe, Neil M.; Eaves, T.?S.; Liste, John R.

    2015-04-30

    , Cambridge, Massachusetts 02139, USA 5Institute of Theoretical Geophysics, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA, UK (Dated: March 16, 2015) Thin viscous fluid threads falling... containing such a micro-structure display a combination of high toughness and stretchability, re- vealed by mechanical tests [7], as they effectively repro- duce nature’s design for spider silk [8]. Similar coiling patterns can be found in a number...

  19. Liquid Ropes: A Geometrical Model for Thin Viscous Jet Instabilities

    NASA Astrophysics Data System (ADS)

    Brun, P.-T.; Audoly, Basile; Ribe, Neil M.; Eaves, T. S.; Lister, John R.

    2015-05-01

    Thin, viscous fluid threads falling onto a moving belt behave in a way reminiscent of a sewing machine, generating a rich variety of periodic stitchlike patterns including meanders, W patterns, alternating loops, and translated coiling. These patterns form to accommodate the difference between the belt speed and the terminal velocity at which the falling thread strikes the belt. Using direct numerical simulations, we show that inertia is not required to produce the aforementioned patterns. We introduce a quasistatic geometrical model which captures the patterns, consisting of three coupled ordinary differential equations for the radial deflection, the orientation, and the curvature of the path of the thread's contact point with the belt. The geometrical model reproduces well the observed patterns and the order in which they appear as a function of the belt speed.

  20. Multiple jet study data correlations. [data correlation for jet mixing flow of air jets

    NASA Technical Reports Server (NTRS)

    Walker, R. E.; Eberhardt, R. G.

    1975-01-01

    Correlations are presented which allow determination of penetration and mixing of multiple cold air jets injected normal to a ducted subsonic heated primary air stream. Correlations were obtained over jet-to-primary stream momentum flux ratios of 6 to 60 for locations from 1 to 30 jet diameters downstream of the injection plane. The range of geometric and operating variables makes the correlations relevant to gas turbine combustors. Correlations were obtained for the mixing efficiency between jets and primary stream using an energy exchange parameter. Also jet centerplane velocity and temperature trajectories were correlated and centerplane dimensionless temperature distributions defined. An assumption of a Gaussian vertical temperature distribution at all stations is shown to result in a reasonable temperature field model. Data are presented which allow comparison of predicted and measured values over the range of conditions specified above.

  1. Direct numerical simulation of a liquid sheet in a compressible gas stream in axisymmetric and planar configurations

    Microsoft Academic Search

    George A. Siamas; Xi Jiang

    2007-01-01

    A thin liquid sheet present in the shear layer of a compressible gas jet is investigated using an Eulerian approach with mixed-fluid\\u000a treatment for the governing equations describing the gas–liquid two-phase flow system, where the gas is treated as fully compressible\\u000a and the liquid as incompressible. The effects of different topological configurations, surface tension, gas pressure and liquid\\u000a sheet thickness

  2. Water vapour jets inside the plume of gas leaving Enceladus.

    PubMed

    Hansen, C J; Esposito, L W; Stewart, A I F; Meinke, B; Wallis, B; Colwell, J E; Hendrix, A R; Larsen, K; Pryor, W; Tian, F

    2008-11-27

    A plume of water vapour escapes from fissures crossing the south polar region of the Saturnian moon Enceladus. Tidal deformation of a thin surface crust above an internal ocean could result in tensile and compressive stresses that would affect the width of the fissures; therefore, the quantity of water vapour released at different locations in Enceladus' eccentric orbit is a crucial measurement of tidal control of venting. Here we report observations of an occultation of a star by the plume on 24 October 2007 that revealed four high-density gas jets superimposed on the background plume. The gas jet positions coincide with those of dust jets reported elsewhere inside the plume. The maximum water column density in the plume is about twice the density reported earlier. The density ratio does not agree with predictions-we should have seen less water than was observed in 2005. The ratio of the jets' bulk vertical velocities to their thermal velocities is 1.5 +/- 0.2, which supports the hypothesis that the source of the plume is liquid water, with gas accelerated to supersonic velocity in nozzle-like channels. PMID:19037310

  3. Defrosting of a Heat Exchanger for Precooled Turbojet Engines Using Jet Impingement

    NASA Astrophysics Data System (ADS)

    Fukiba, Katsuyoshi; Inoue, Shou; Sato, Tetsuya; Ohkubo, Hidetoshi

    An innovative defrosting method for precooled turbojet engines are presented, and validated in this study using experimental methods. High speed gas jet was impinged on the cooling tubes of a heat exchanger for the purpose of defrosting. The coolant of the heat exchanger was liquid nitrogen, and whose temperature was 83K. The air flow speed, the air temperature and the air humidity were 1.0m/s, 23ºC and 59%, respectively. The effects of the jet duration, jet intervals and humidity of the jet gas on the heat exchange were assessed. As a result, we found that the presenting defrosting method is valid for the defrosting of the precooler.

  4. Method and apparatus for cutting, abrading, and drilling with sublimable particles and vaporous liquids

    DOEpatents

    Bingham, D.N.; Swainston, R.C.; Palmer, G.L.

    1998-03-31

    A gas delivery system provides a first gas which is in a liquid state under extreme pressure and in a gaseous state under intermediate pressure. A particle delivery system provides a slurry comprising the first gas in a liquid state and a second gas in a solid state. The second gas is selected so that it will solidify at a temperature at or above the temperature of the first gas in a liquid state. A nozzle assembly connected to the gas delivery system and to the particle delivery system produces a stream having a high velocity central jet comprising the slurry, a liquid sheath surrounding the central jet comprising the first gas in a liquid state and an outer jacket surrounding the liquid sheath comprising the first gas in a gas state. 19 figs.

  5. Experimental and analytical studies on high-speed plane jet along concave wall simulating IFMIF Li target flow

    Microsoft Academic Search

    Hideo Nakamura; Kazuhiro Itoh; Yutaka Kukita; Mizuho Ida; Yoshio Kato; Hiroshi Maekawa; Hiroji Katsuta

    1998-01-01

    As part of the conceptual design activity (CDA) of the international fusion materials irradiation facility (IFMIF), the characteristics of the high-speed liquid lithium (Li) plane jet target flow have been studied by water experiments and numerical analyses for both heating and non-heating conditions. The simulated prototypal-size water jet flows were stable over the entire length of ?130 mm at the

  6. Improved e-Jet Printing -TFOT Improved e-Jet Printing

    E-print Network

    Rogers, John A.

    Improved e-Jet Printing - TFOT Home Sections News Articles Forums About Us Improved e-Jet Printing-jet printing. As opposed to conventional ink-jet printers, where heat or mechanical vibrations are used to mobilize the ink stream, e-jet printers use electric fields to pull fluids through the printing nozzles

  7. Water jet rebounds on hydrophobic surfaces : a first step to jet micro-fluidics.

    E-print Network

    Paris-Sud XI, Université de

    1 Water jet rebounds on hydrophobic surfaces : a first step to jet micro-fluidics. F. Celestini of the jet to the bi-dimensional one of the film. A true jet rebound on a solid surface, for which the fundamental problem of knowing why such capillary hydraulic jump gives rise to this unexpected jet rebound

  8. Jet mixer noise suppressor using acoustic feedback

    NASA Astrophysics Data System (ADS)

    Rice, Edward J.

    1993-04-01

    The present invention generally relates to providing an improved jet mixer noise suppressor for high speed jets that rapidly mixes high speed air flow with a lower speed air flow, and more particularly, relates to an improved jet mixer noise suppressor that uses feedback of acoustic waves produced by the interaction of sheer flow instability waves with an obstacle downstream of the jet nozzle.

  9. Jet mixer noise suppressor using acoustic feedback

    NASA Astrophysics Data System (ADS)

    Rice, Edward J.

    1995-02-01

    The present invention generally relates to providing an improved jet mixer noise suppressor for high speed jets that rapidly mixes high speed air flow with a lower speed air flow, and more particularly, relates to an improved jet mixer noise suppressor that uses feedback of acoustic waves produced by the interaction of shear flow instability waves with an obstacle downstream of the jet nozzle.

  10. Jet mixer noise suppressor using acoustic feedback

    NASA Technical Reports Server (NTRS)

    Rice, Edward J. (inventor)

    1995-01-01

    The present invention generally relates to providing an improved jet mixer noise suppressor for high speed jets that rapidly mixes high speed air flow with a lower speed air flow, and more particularly, relates to an improved jet mixer noise suppressor that uses feedback of acoustic waves produced by the interaction of shear flow instability waves with an obstacle downstream of the jet nozzle.

  11. The interaction between two radial jets 

    E-print Network

    Gruber, Thomas Clifton

    1993-01-01

    Arrays of impinging jets are used in industry for heat and mass transfer processes. A new type of jet was recently developed which could be utilized in such arrays. This jet is the radial jet and it offers the advantages of variable net force...

  12. Pneumatically actuated micromachined synthetic jet modulators

    Microsoft Academic Search

    David J. Coe; Mark G. Allen; Christopher S. Rinehart; Ari Glezer

    2006-01-01

    Results presented in the synthetic jet literature have focused on the demonstration of and application of one or more single-orifice synthetic jet actuators in jet vectoring and other aerodynamic applications. For these applications, amplitude and phase modulation techniques are often used in conjunction with the oscillatory nature of the synthetic jet flow to achieve the desired results. In this work

  13. Performance Improvement of High Speed Jet Fan

    Microsoft Academic Search

    Young-Seok Choi; Joon-Hyung Kim; Kyoung-Yong Lee; Sang-Ho Yang

    2010-01-01

    In this paper, a numerical study has been carried out to investigate the influence of jet fan design variables on the performance of a jet fan. In order to achieve an optimum jet fan design and to explain the interactions between the different geometric configurations in the jet fan, three-dimensional computational fluid dynamics and the Design of Experiments method have

  14. Factorization for generic jet production

    SciTech Connect

    Bauer, Christian W.; Hornig, Andrew; Tackmann, Frank J. [Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)

    2009-06-01

    Factorization is the central ingredient in any theoretical prediction for collider experiments. We introduce a factorization formalism that can be applied to any desired observable, like event shapes or jet observables, for any number of jets and a wide range of jet algorithms in leptonic or hadronic collisions. This is achieved by using soft-collinear effective theory to prove the formal factorization of a generic fully differential cross section in terms of a hard coefficient, and generic jet and soft functions. In this formalism, whether a given observable factorizes in the usual sense, depends on whether it is inclusive enough, so the jet functions can be calculated perturbatively. The factorization formula for any such observable immediately follows from our general result, including the precise definition of the jet and soft functions appropriate for the observable in question. As examples of our formalism, we work out several results in two-jet production for both e{sup +}e{sup -} and pp collisions. For the latter, we also comment on how our formalism allows one to treat underlying events and beam remnants.

  15. Performance of jets at CMS

    NASA Astrophysics Data System (ADS)

    Schröder, Matthias; CMS collaboration

    2015-02-01

    The calibration and reconstruction of jets critically relies on the performance of the calorimeters. Extending out to large pseudorapidities, the measurements depend on the interplay between forward calorimeters, central calorimeters, and the tracking system. The high number of additional pile-up interactions poses further complications. In CMS, these difficulties are overcome using the 'particle-flow' approach, which aims at reconstructing individually each particle in the event prior to the jet clustering. Measurements of the jet energy scale and the procedure for jet energy calibration in CMS are reviewed, which are performed with dijet, photon + jet, and Z+jet data collected in proton-proton collisions at a centre-of-mass energy of 8 TeV, corresponding to an integrated luminosity of 19.6 fb?1. The effect of pile-up interactions and the state of the art mitigation techniques used in CMS as well as the main sources of uncertainty of the jet energy calibration are also presented.

  16. Bubble departure in the direct-contact boiling field with a continuous liquid-liquid interface

    SciTech Connect

    Kadoguchi, Katsuhiko [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569 (Japan)

    2007-01-15

    Behavior of vapor bubbles was experimentally investigated in the boiling field where a volatile liquid layer of per-fluorocarbon PF5050 (boiling point 306K) was directly in contact with an immiscible hot liquid layer of water above it. Heat was supplied to the continuous liquid-liquid interface by the impingement of the downward hot water jet. Vapor bubbles were generated not only from this continuous interface but from a large number of PF5050 droplets floating on it. According to precise observation, incipience of boiling did not occur at the liquid-liquid interface but in the PF5050 liquid close to the interface in both cases of continuous and dispersed interfaces. As a result, the bubbles broke up the thin PF5050 liquid film above them and rose up into the water layer. This bubble departure phenomenon, which does not occur in the ordinary pool boiling field on the solid heating wall, is very important to evaluate the heat transfer performance in the present direct-contact boiling system. For modeling this behavior, sizes of the bubbles were measured at the moment just after they were released into the water pool. Volumes of the bubbles were larger in the case of departing from the continuous liquid-liquid interface than from the droplets. This tendency could be explained by taking into account the buoyancy force acting on unit area of the thin PF5050 liquid film above the bubble before departure, which was one of the most important parameters for the liquid film breakdown. (author)

  17. Experimental study on spray characteristics of alternate jet fuels using Phase Doppler Anemometry

    NASA Astrophysics Data System (ADS)

    Kannaiyan, Kumaran; Sadr, Reza

    2013-11-01

    Gas-to-Liquid (GTL) fuels have gained global attention due to their cleaner combustion characteristics. The chemical and physical properties of GTL jet fuels are different from conventional jet fuels owing to the difference in their production methodology. It is important to study the spray characteristics of GTL jet fuels as the change of physical properties can affect atomization, mixing, evaporation and combustion process, ultimately affecting emission process. In this work, spray characteristics of two GTL synthetic jet fuels are studied using a pressure-swirl nozzle at different injection pressures and atmospheric ambient condition. Phase Doppler Anemometry (PDA) measurements of droplet size and velocity are compared with those of regular Jet A-1 fuel at several axial and radial locations downstream of the nozzle exit. Experimental results show that although the GTL fuels have different physical properties such as viscosity, density, and surface tension, among each other the resultant change in the spray characteristics is insignificant. Furthermore, the presented results show that GTL fuel spray characteristics exhibit close similarity to those of Jet A-1 fuel. Gas-to-Liquid (GTL) fuels have gained global attention due to their cleaner combustion characteristics. The chemical and physical properties of GTL jet fuels are different from conventional jet fuels owing to the difference in their production methodology. It is important to study the spray characteristics of GTL jet fuels as the change of physical properties can affect atomization, mixing, evaporation and combustion process, ultimately affecting emission process. In this work, spray characteristics of two GTL synthetic jet fuels are studied using a pressure-swirl nozzle at different injection pressures and atmospheric ambient condition. Phase Doppler Anemometry (PDA) measurements of droplet size and velocity are compared with those of regular Jet A-1 fuel at several axial and radial locations downstream of the nozzle exit. Experimental results show that although the GTL fuels have different physical properties such as viscosity, density, and surface tension, among each other the resultant change in the spray characteristics is insignificant. Furthermore, the presented results show that GTL fuel spray characteristics exhibit close similarity to those of Jet A-1 fuel. Funded by Qatar Science and Technology Park.

  18. Unsteady Jets in Crossflow

    NASA Technical Reports Server (NTRS)

    Zaman, K. B. M. Q.

    2004-01-01

    The effect of periodic perturbation on jet in cross-flow (JICF) is reviewed. In the first part of the paper, flow visualization result from several past works are discussed. Beginning with description of the characteristic vortex systems of a JICF it is shown that specific perturbation techniques work by organizing and intensifying specific vortex systems. Oscillatory blowing works primarily through an organization of the shear layer vortices. In the second part of the paper, results of an ongoing experiment involving another mechanical perturbation technique are discussed. It involves two tabs at the orifice exit whose asymmetry in placement is reversed periodically. It directly modulates the counter-rotating vortex pair (CVP). Effects of the perturbation for an array of three adjacent orifices are exploded. The flowfield data show an improvement in mixing compared to the unperturbed case.

  19. Micromachined chemical jet dispenser

    DOEpatents

    Swierkowski, Steve P. (Livermore, CA)

    1999-03-02

    A dispenser for chemical fluid samples that need to be precisely ejected in size, location, and time. The dispenser is a micro-electro-mechanical systems (MEMS) device fabricated in a bonded silicon wafer and a substrate, such as glass or silicon, using integrated circuit-like fabrication technology which is amenable to mass production. The dispensing is actuated by ultrasonic transducers that efficiently produce a pressure wave in capillaries that contain the chemicals. The 10-200 .mu.m diameter capillaries can be arranged to focus in one spot or may be arranged in a larger dense linear array (.about.200 capillaries). The dispenser is analogous to some ink jet print heads for computer printers but the fluid is not heated, thus not damaging certain samples. Major applications are in biological sample handling and in analytical chemical procedures such as environmental sample analysis, medical lab analysis, or molecular biology chemistry experiments.

  20. Micromachined chemical jet dispenser

    DOEpatents

    Swierkowski, S.P.

    1999-03-02

    A dispenser is disclosed for chemical fluid samples that need to be precisely ejected in size, location, and time. The dispenser is a micro-electro-mechanical systems (MEMS) device fabricated in a bonded silicon wafer and a substrate, such as glass or silicon, using integrated circuit-like fabrication technology which is amenable to mass production. The dispensing is actuated by ultrasonic transducers that efficiently produce a pressure wave in capillaries that contain the chemicals. The 10-200 {micro}m diameter capillaries can be arranged to focus in one spot or may be arranged in a larger dense linear array (ca. 200 capillaries). The dispenser is analogous to some ink jet print heads for computer printers but the fluid is not heated, thus not damaging certain samples. Major applications are in biological sample handling and in analytical chemical procedures such as environmental sample analysis, medical lab analysis, or molecular biology chemistry experiments. 4 figs.

  1. Water cooled steam jet

    DOEpatents

    Wagner, E.P. Jr.

    1999-01-12

    A water cooled steam jet for transferring fluid and preventing vapor lock, or vaporization of the fluid being transferred, has a venturi nozzle and a cooling jacket. The venturi nozzle produces a high velocity flow which creates a vacuum to draw fluid from a source of fluid. The venturi nozzle has a converging section connected to a source of steam, a diffuser section attached to an outlet and a throat portion disposed there between. The cooling jacket surrounds the venturi nozzle and a suction tube through which the fluid is being drawn into the venturi nozzle. Coolant flows through the cooling jacket. The cooling jacket dissipates heat generated by the venturi nozzle to prevent vapor lock. 2 figs.

  2. Water cooled steam jet

    DOEpatents

    Wagner, Jr., Edward P. (Idaho Falls, ID)

    1999-01-01

    A water cooled steam jet for transferring fluid and preventing vapor lock, or vaporization of the fluid being transferred, has a venturi nozzle and a cooling jacket. The venturi nozzle produces a high velocity flow which creates a vacuum to draw fluid from a source of fluid. The venturi nozzle has a converging section connected to a source of steam, a diffuser section attached to an outlet and a throat portion disposed therebetween. The cooling jacket surrounds the venturi nozzle and a suction tube through which the fluid is being drawn into the venturi nozzle. Coolant flows through the cooling jacket. The cooling jacket dissipates heat generated by the venturi nozzle to prevent vapor lock.

  3. Acoustics of Excited Jets: A Historical Perspective

    NASA Technical Reports Server (NTRS)

    Brown, Cliffard A.

    2005-01-01

    The idea that a jet may be excited by external forcing is not new. The first published demonstration of a jet responding to external pressure waves occurred in the mid-1800's. It was not, however, until the 1950's, with the advent of commercial jet aircraft, that interest in the subject greatly increased. Researchers first used excited jets to study the structure of the jet and attempt to determine the nature of the noise sources. The jet actuators of the time limited the range (Reynolds and Mach numbers) of jets that could be excited. As the actuators improved, more realistic jets could be studied. This has led to a better understanding of how jet excitation may be used not only as a research tool to understand the flow properties and noise generation process, but also as a method to control jet noise.

  4. Real jet effects on dual jets in a crossflow

    NASA Technical Reports Server (NTRS)

    Schetz, J. A.

    1984-01-01

    A 6-ft by 6-ft wind tunnel section was modification to accommodate the 7-ft wide NASA dual-jet flate model in an effort to determine the effects of nonuniform and/or noncircular jet exhaust profiles on the pressure field induced on a nearby surface. Tests completed yield surface pressure measurements for a 90 deg circular injector producing exit profiles representative of turbofan nozzles (such as the TF-34 nozzle). The measurements were obtained for both tandem and side-by-side jet configurations, jet spacing of S/D =2, and velocity ratios of R=2.2 and 4.0. Control tests at the same mass flow rate but with uniform exit velocity profiles were also conducted, for comparison purposes. Plots for 90 deg injection and R=2.2 show that the effects of exit velocity profile nonuniformity are quite significant.

  5. Pump for Saturated Liquids

    NASA Technical Reports Server (NTRS)

    Elliott, D. G.

    1986-01-01

    Boiling liquids pumped by device based on proven components. Expanding saturated liquid in nozzle and diverting its phases along separate paths in liquid/vapor separator raises pressure of liquid. Liquid cooled in process. Pump makes it unnecessary to pressurize cryogenic liquids in order to pump them. Problems of introducing noncondensable pressurizing gas avoided.

  6. Chiral liquids

    NASA Astrophysics Data System (ADS)

    Zakharov, V. I.

    2015-05-01

    We review briefly properties of chiral liquids, or liquids with massless fermionic constituents. We concentrate on three effects, namely, the low ratio of viscosity ? to entropy density s, chiral magnetic and vortical effects. We sketch standard derivations of these effects in the hydrodynamic approximation and then concentrate on possibile unifying approach which is based on consideration of the (anomalously) conserved axial current. The point is that the conservation of chirality is specific for the microscopic, field-theoretic description of massless fermions and their interactions. On the macroscopic side, the standard hydrodynamic equations are not consistent, generally speaking, with conservation of a helical macroscopic motion. Imposing extra constraints on the hydrodynamics might resolve this "clash-of-symmetries" paradox.

  7. Feasibility Study for a New Business Jet

    E-print Network

    Mousa, Yasser Abdullah

    2009-05-15

    method would allow using similar classifications and introducing a new group, which is supersonic business jet. This group contains jets that have different speed characteristics than others. The other groups are light... aircrafts in business jets are able to carry up to 60 passengers with a range of 6,000 miles. Supersonic business jet group Supersonic business jets (SSBJ) have been under development for a long time. However, committed startup companies decided to bring the supersonic...

  8. Jets and Jet-like correlations in STAR

    E-print Network

    Alice Ohlson; for the STAR Collaboration

    2012-10-08

    The propagation and modification of hard-scattered partons in the QGP can be studied using various types of jet and jet-like correlation measurements. The STAR detector with its full azimuthal and large pseudorapidity acceptance, as well as its wide transverse momentum (pT) coverage, is well-suited for these measurements. At mid-rapidity, azimuthal correlations of charged hadrons with the axis of a reconstructed trigger jet are used to study the modification of jet shapes and associated hadron yields from p+p to Au+Au. Dihadron correlations with back-to-back high-pT hadron pairs are used to investigate dijets and fragmentation biases. STAR's increased particle identification capabilities due to the Time-Of-Flight detector are utilized to investigate the differences between jet-related and bulk-related particle production. Dihadron correlations with identified trigger particles provide experimental tests of simple recombination theories. The comprehensive set of STAR jet-quenching measurements can be used to further constrain theories of parton energy loss at RHIC.

  9. Enhancement of Nucleate Boiling Heat Flux on Macro/Micro-Structured Surfaces Cooled by Multiple Impinging Jets

    NASA Technical Reports Server (NTRS)

    Kugler, Scott Lee

    1997-01-01

    An experimental investigation of nucleate boiling heat transfer from modified surfaces cooled by multiple in-line impinging circular jets is reported and found to agree with single jet results. A copper block is heated from the back by two electrical arcs, and cooled on the opposite side by three identical liquid jets of distilled water at subcoolings of 25 C 50 C and 77 C and Freon 113 at 24 C subcooling. Liquid flow rates are held constant at 5, 10, and 15 GPH for each of the three jets with jet velocities ranging from 1.4 m/s to 1 1.2 m/s and jet diameters from 0.95 mm to 2.2 mm. To increase the maximum heat flux (CHF) and heat removal rate, the boiling surface was modified by both macro and micro enhancements. Macro modification consists of machined radial grooves in the boiling surface arranged in an optimally designed pattern to allow better liquid distribution along the surface. These grooves also reduce splashing of liquid droplets, and provide 'channels' to sweep away bubbles. Micro modification was achieved by flame spraying metal powder on the boiling surface, creating a porous, sintered surface. With the addition of both micro and macro structured enhancements, maximum heat flux and nucleate boiling can be enhanced by more than 200%. Examination of each surface modification separately and together indicates that at lower superheats, the micro structure provides the enhanced heat transfer by providing more nucleation sites, while for higher superheats the macro structure allows better liquid distribution and bubble removal. A correlation is presented to account for liquid subcoolings and surface enhancements, in addition to the geometrical and fluid properties previously reported in the literature.

  10. Development, characterization and application of momentum dominated jet microfluidics

    NASA Astrophysics Data System (ADS)

    Resto, Pedro J.

    Microfluidics is the scientific field that deals with the study and control of small volumes of liquid. Microfluidics has found its way into many areas of science including biotechnology, the life sciences, defense, public health and pharmacology. One of the most important aspects of microfluidics is the ability to move and control liquid at the micro scale. The laws of physics at the micro scale are different from the laws of physics at the macro scale. For example, the macro scale is dominated by momentum, turbulence and gravity whereas surface tension, inter-atomic forces, capillary action, viscosity, laminar flow, diffusion, fluidic resistance and surface area to volume ratios dominate the micro scale. The research community has taken advantage of these micro scale forces to perform tasks not possible at the macro scale. However, there exists a transition zone between the micro and macro scale where both inertia and viscosity of the fluid are finite, between Stokes flow and inviscid flow, so that inertia or viscosity cannot be discounted. This thesis work is on the characterization of jet microfluidics; this is the control of liquid at the micro scale using inertia. We define two flow regimes: inertia enhanced passive pumping and inertia actuated flow. We then apply our microfluidic technology to electrophysiology where we develop of a new high-throughput drug discovery tool using jet microfluidics and patch clamping.

  11. High-speed monodisperse droplet generation by ultrasonically controlled micro-jet breakup

    NASA Astrophysics Data System (ADS)

    Frommhold, Philipp Erhard; Lippert, Alexander; Holsteyns, Frank Ludwig; Mettin, Robert

    2014-04-01

    A liquid jet that is ejected from a nozzle into air will disintegrate into drops via the well-known Plateau-Rayleigh instability within a certain range of Ohnesorge and Reynolds numbers. With the focus on the micrometer scale, we investigate the control of this process by superimposing a suitable ultrasonic signal, which causes the jet to break up into a very precise train of monodisperse droplets. The jet leaves a pressurized container of liquid via a small orifice of about 20 ?m diameter. The break-up process and the emerging droplets are recorded via high-speed imaging. An extended parameter study of exit speed and ultrasonic frequency is carried out for deionized water to evaluate the jet's state and the subsequent generation of monodisperse droplets. Maximum exit velocities obtained reach almost 120 m s-1, and frequencies have been applied up to 1.8 MHz. Functionality of the method is confirmed for five additional liquids for moderate jet velocities 38 m s-1. For the uncontrolled jet disintegration, the drop size spectra revealed broad distributions and downstream drop growth by collision, while the acoustic control generated monodisperse droplets with a standard deviation less than 0.5 %. By adjustment of the acoustic excitation frequency, drop diameters could be tuned continuously from about 30 to 50 ?m for all exit speeds. Good agreement to former experiments and theoretical approaches is found for the relation of overpressure and jet exit speed, and for the observed stability regions of monodisperse droplet generation in the parameter plane of jet speed and acoustic excitation frequency. Fitting of two free parameters of the general theory to the liquids and nozzles used is found to yield an even higher precision. Furthermore, the high-velocity instability limit of regular jet breakup described by von Ohnesorge has been superseded by more than a factor of two without entering the wind-induced instability regime, and monodisperse droplet generation was always achievable. Thus, the reliable and robust realization of tunable high-speed monodisperse micro-droplet trains is demonstrated. Some implication for applications is discussed.

  12. High-speed multi-jets printing using laser forward transfer: time-resolved study of the ejection dynamics.

    PubMed

    Biver, Emeric; Rapp, Ludovic; Alloncle, Anne-Patricia; Serra, Pere; Delaporte, Philippe

    2014-07-14

    This paper extends the current understanding of the laser-induced forward transfer (LIFT) process to the multi-jets ejection problem. LIFT has already been used to print micrometer-sized droplets from a liquid donor substrate with single pulse experiments. Here we study the dynamics of the high-speed multi-jets formation from silver nanoparticles ink films with a time-resolved imaging technique. A galvanometric mirrors head controls the spacing between adjacent pulses by scanning the focused beam of a high repetition rate UV picosecond laser along an ink-coated donor substrate. The laser pulses interact with the liquid film and generate cavitation bubbles that propel the ink away from the substrate and form the jets. When the spacing between consecutive pulses is substantially higher than the maximum diameter of the bubbles, there is no interaction between adjacent jets, and these remain unperturbed. However, when the pulses are brought closer significant jet-jet interaction takes place, which results in a clear deviation from the single jet dynamics. Thus, the cavitation bubbles acquire different shapes, the ink is ejected faster and along different directions depending on the spacing between the pulses, and each bubble alters the evolution of the previous one and shifts away from it. PMID:25090527

  13. Capillary jets in normal gravity: Asymptotic stability analysis and excitation using Maxwell and ultrasonic radiation stresses

    NASA Astrophysics Data System (ADS)

    Lonzaga, Joel Barci

    Both modulated ultrasonic radiation pressure and oscillating Maxwell stress from a voltage-modulated ring electrode are employed to excite low-frequency capillary modes of a weakly tapered liquid jet issuing from a nozzle. The capillary modes are waves formed at the surface of the liquid jet. The ultrasound is internally applied to the liquid jet waveguide and is cut off at a location resulting in a significantly enhanced oscillating radiation stress near the cutoff location. Alternatively, the thin electrode can generate a highly localized oscillating Maxwell stress on the jet surface. Experimental evidence shows that a spatially unstable mode with positive group velocity (propagating downstream from the excitation source) and a neutral mode with negative group velocity are both excited. Reflection at the nozzle boundary converts the neutral mode into an unstable one that interferes with the original unstable mode. The interference effect is observed downstream from the source using a laser-based optical extinction technique that detects the surface waves while the modulation frequency is scanned. This technique is very sensitive to small-amplitude disturbances. Existing linear, convective stability analyses on liquid jets accounting for the gravitational effect (i.e. varying radius and velocity) appear to be not applicable to non-slender, slow liquid jets considered here where the gravitational effect is found substantial at low flow rates. The multiple-scales method, asymptotic expansion and WKB approximation are used to derive a dispersion relation for the capillary wave similar to one obtained by Rayleigh but accounting for the gravitational effect. These mathematical tools aided by Langer's transformation are also used to derive a uniformly valid approximation for the acoustic wave propagation in a tapered cylindrical waveguide. The acoustic analytical approximation is validated by finite-element calculations. The jet response is modeled using a hybrid of Fourier analysis and the WKB-type analysis as proposed by Lighthill. The former derives the mode response to a highly localized source while the latter governs the mode propagation in a weakly inhomogeneous jet away from the source.

  14. Supersonic jet screech tone cancellation

    NASA Technical Reports Server (NTRS)

    Nagel, R. T.; Denham, J. W.; Papathanasiou, A. G.

    1983-01-01

    A new method of supersonic jet screech tone reduction is presented. The method utilizes a sound reflecting surface positioned upstream of the nozzle exit a distance of one-quarter wavelength of the fundamental screech tone. The reflector establishes a standing wave pattern of acoustic waves with a node at the nozzle exit plane. The pressure minimum at the exit halts the screech tone feedback mechanism. Experimental results indicate that the method eliminates supersonic jet screech as effectively as the currently accepted technique using an intrusive tab, but without distortion of the jet flow. The change in shock cell spacing, which occurs with an intrusive tab, does not occur when screech is cancelled with the new technique. The broadband shock-associated noise is also influenced much less when the jet screech tones are eliminated by the new method.

  15. Supersonic jet screech tone cancellation

    NASA Astrophysics Data System (ADS)

    Nagel, R. T.; Denham, J. W.; Papathanasiou, A. G.

    1983-11-01

    A new method of supersonic jet screech tone reduction is presented. The method utilizes a sound reflecting surface positioned upstream of the nozzle exit a distance of one-quarter wavelength of the fundamental screech tone. The reflector establishes a standing wave pattern of acoustic waves with a node at the nozzle exit plane. The pressure minimum at the exit halts the screech tone feedback mechanism. Experimental results indicate that the method eliminates supersonic jet screech as effectively as the currently accepted technique using an intrusive tab, but without distortion of the jet flow. The change in shock cell spacing, which occurs with an intrusive tab, does not occur when screech is cancelled with the new technique. The broadband shock-associated noise is also influenced much less when the jet screech tones are eliminated by the new method.

  16. Twin-jet screech suppression

    NASA Astrophysics Data System (ADS)

    Shaw, L. L.

    1989-04-01

    Results are reported from an experimental investigation of screech noise in twin jet-engine configurations and of methods for suppressing this noise. The acoustic mechanisms of screech generation and amplification are reviewed; the experimental setup (in which acoustic and phase-averaged schlieren data are obtained on a 4.7-percent scale model of an F-15 aircraft equipped with axisymmetric nozzles) is described; and the results are presented in extensive graphs and flow visualizations. Screech tones with amplitudes up to 163 dB are measured, with amplification by up to 20 dB due to interplume coupling. Suppression by active noise cancellation and by shifting the nozzle exit planes is found to be ineffective; small tabs mounted in the exit plane are very effective in suppressing screech from both single and twin jets, while a small secondary jet is effective for single-jet screech.

  17. Jet production at hadron colliders

    E-print Network

    Jouttenus, Teppo T. (Teppo Tapani)

    2012-01-01

    Hadronic jets feature in many final states of interest in modern collider experiments. They form a significant Standard Model background for many proposed new physics processes and also probe QCD interactions at several ...

  18. Radial flow pulse jet mixer

    DOEpatents

    VanOsdol, John G.

    2013-06-25

    The disclosure provides a pulse jet mixing vessel for mixing a plurality of solid particles. The pulse jet mixing vessel is comprised of a sludge basin, a flow surface surrounding the sludge basin, and a downcoming flow annulus between the flow surface and an inner shroud. The pulse jet mixing vessel is additionally comprised of an upper vessel pressurization volume in fluid communication with the downcoming flow annulus, and an inner shroud surge volume separated from the downcoming flow annulus by the inner shroud. When the solid particles are resting on the sludge basin and a fluid such as water is atop the particles and extending into the downcoming flow annulus and the inner shroud surge volume, mixing occurs by pressurization of the upper vessel pressurization volume, generating an inward radial flow over the flow surface and an upwash jet at the center of the sludge basin.

  19. Relativistic Jets in Stellar Systems

    NASA Astrophysics Data System (ADS)

    Gallo, Elena

    Albeit their nature remains elusive, relativistic, collimated outflows of energy and particles appear to be a nearly ubiquitous feature of accreting black holes. As evidence accumulates for a dominant role of the jet in dissipating the liberated accretion power, questions around their powering mechanism and even composition remain unanswered. In this chapter, I will describe the main observational properties of relativistic jets from black hole X-ray binaries, with a particular emphasis on recent developments around three main topics: (i) the role and relative importance of the accretion flow, relativistic jet and equatorial wind; (ii) the existence of global luminosity-luminosity correlation(s) in quiescent and hard state black hole X-ray binaries, and their interpretation(s); (iii) (ways of estimating) the total jet power, and its relation to black hole spin.

  20. Low-Level Coastal Jets

    NSDL National Science Digital Library

    2014-09-14

    Low-level coastal jets occur along many coastlines. Winds may exceed 35 knots and lead to high waves and significant low-level vertical wind shear. Thus, low-level coastal jets present a hazard to both marine and aviation operations in the coastal zone. This core module describes the features of coastal jets and explores the conditions under which they form. Like other foundation modules in the Mesoscale Primer, this module starts with a forecast scenario and concludes with a concise summary and a final exam. By the end of this module, you should have sufficient background to diagnose and forecast coastal jets around the world and to use this knowledge to understand the implications for operational decisions.

  1. Jet Perturbation by HE target

    SciTech Connect

    Poulsen, P; Kuklo, R M

    2001-03-01

    We have previously reported the degree of attenuation and perturbation by a Cu jet passing through Comp B explosive. Similar tests have now been performed with high explosive (HE) targets having CJ pressures higher than and lower than the CJ pressure of Comp B. The explosives were LX-14 and TNT, respectively. We found that the measured exit velocity of the jet where it transitions from perturbed to solid did not vary significantly as a function of HE type for each HE thickness. The radial momentum imparted to the perturbed jet segment did vary as a function of HE type, however, and we report the radial spreading of the jet and the penetration of a downstream target as a function of HE type and thickness.

  2. Liquid air mixing system

    NASA Technical Reports Server (NTRS)

    Martin, Robert B. (Inventor)

    1997-01-01

    A device for mixing liquid nitrogen and liquid oxygen to form liquid air. The mixing device consists of a tube for transferring liquid oxygen positioned within a tube for transferring liquid nitrogen. Supply vessels for liquid oxygen and liquid nitrogen are equally pressurized and connected to the appropriate tubes. Liquid oxygen and nitrogen flow from the supply vessels through the respective tubes and are mixed to form liquid air upon exiting the outlets of the tube. The resulting liquid air is transferred to a holding vessel.

  3. Jet Quenching with Parton evolution

    E-print Network

    Luan Cheng; Enke Wang

    2009-10-08

    We report the evolution effects on jet energy loss with detailed balance. The initial conditions and parton evolution based on perturbative QCD in the chemical non-equilibrated medium and Bjorken expanding medium at RHIC are determined. The parton evolution affect the jet energy loss evidently. This will increase the energy and propagating distance dependence of the parton energy loss and will affect the shape of suppression of moderately high P_{T} hadron spectra.

  4. Numerical Modeling of Munroe Jets

    NASA Astrophysics Data System (ADS)

    Mader, Charles; Gittings, Michael

    2007-06-01

    Munroe jets are formed by the oblique interaction of detonation products from two explosive charges separated by an air gap. The jet consists of a high velocity jet of low density precursor gases and particles that travel faster than the primary jet which is a high pressure regular shock reflection. The Los Alamos PHERMEX Data Volumes [1] contain 40 radiographs taken by Douglas Venable in the 1960's of Munroe Jets generated by Composition B explosive charges separated by 5 to 80 mm of air. In several of the experiments the Munroe jets interacted with thin Tantalum foils and with aluminum plates. The PHERMEX experiments were modeled using the AMR Eulerian reactive hydrodynamic code, NOBEL [2,3], When the detonation arrives at the bottom of the gap, the detonation product s expand against the air and precursor gases travel at high velocity ahead of the detonation wave in the explosive. The expanding detonation products from the explosive collide and result in a high pressure regular shock reflection.. Interaction with a metal plate consists of first the interaction of the precursor gases and then the high pressure regular shock reflection arrives to further damage the metal plate. [1] Los Alamos PHERMEX Data, Volumes I, II, and III, UC Press 1980. [2] Numerical Modeling of Water Waves, Second Edition, Charles L. Mader, CRC Press 2004 [3] Numerical Modeling of Explosions and Propellants, Charles L. Mader, CRC Press 1998.

  5. Chaotic mixing across oceanic jets

    SciTech Connect

    Miller, P.; Jones, C.K.; Haller, G. [Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912 (United States); Pratt, L. [Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912 (United States)]|[Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 (United States)

    1996-06-01

    The perspective of geometric dynamical systems is used to study the transport of fluid across oceanic jets. We study the mixing associated with the simplest analytical models for jets, namely, neutral modes superimposed on a base mean flow, where the base flow and the neutral modes are approximately potential vorticity conserving. The base jet plus a single neutral mode is an integrable flow in the appropriate moving frame, and heteroclinic orbits act as impenetrable boundaries separating different regions of phase space. Superimposing more than one neutral mode results in the breakup of these heteroclinic orbits and associated chaotic mixing. Using a cusped jet model we study the case where the perturbation is periodic in time. We present numerical simulations of the Poincar{acute e} map along with calculations of the Melnikov integral which characterizes the exchange rate across such boundaries. The analytical and numerical results show that these models explain mixing along the edges of the jet, but do not appear to explain mixing across the body of the jet. {copyright} {ital 1996 American Institute of Physics.}

  6. Jet Noise Reduction

    NASA Technical Reports Server (NTRS)

    Kenny, Patrick

    2004-01-01

    The Acoustics Branch is responsible for reducing noise levels for jet and fan components on aircraft engines. To do this, data must be measured and calibrated accurately to ensure validity of test results. This noise reduction is accomplished by modifications to hardware such as jet nozzles, and by the use of other experimental hardware such as fluidic chevrons, elliptic cores, and fluidic shields. To insure validity of data calibration, a variety of software is used. This software adjusts the sound amplitude and frequency to be consistent with data taken on another day. Both the software and the hardware help make noise reduction possible. work properly. These software programs were designed to make corrections for atmosphere, shear, attenuation, electronic, and background noise. All data can be converted to a one-foot lossless condition, using the proper software corrections, making a reading independent of weather and distance. Also, data can be transformed from model scale to full scale for noise predictions of a real flight. Other programs included calculations of Over All Sound Pressure Level (OASPL), Effective Perceived Noise Level (EPNL). OASPL is the integration of sound with respect to frequency, and EPNL is weighted for a human s response to different sound frequencies and integrated with respect to time. With the proper software correction, data taken in the NATR are useful in determining ways to reduce noise. display any difference between two or more data files. Using this program and graphs of the data, the actual and predicted data can be compared. This software was tested on data collected at the Aero Acoustic Propulsion Laboratory (AAPL) using a variety of window types and overlaps. Similarly, short scripts were written to test each individual program in the software suite for verification. Each graph displays both the original points and the adjusted points connected with lines. During this summer, data points were taken during a live experiment at the AAPL to measure Nozzle Acoustic Test Rig (NATR) background noise levels. Six condenser microphones were placed in strategic locations around the dome and the inlet tunnel to measure different noise sources. From the control room the jet was monitored with the help of video cameras and other sensors. The data points were recorded, reduced, and plotted, and will be used to plan future modifications to the NATR. The primary goal to create data reduction test programs and provide verification was completed. As a result of the internship, I learned C/C++, UNIX/LINUX, Excel, and acoustic data processing methods. I also recorded data at the AAPL, then processed and plotted it. These data would be useful to compare against existing data. In addition, I adjusted software to work on the Mac OSX platform. And I used the available training resources.

  7. The first calculation of fractional jets

    NASA Astrophysics Data System (ADS)

    Bertolini, Daniele; Thaler, Jesse; Walsh, Jonathan R.

    2015-05-01

    In collider physics, jet algorithms are a ubiquitous tool for clustering particles into discrete jet objects. Event shapes offer an alternative way to characterize jets, and one can define a jet multiplicity event shape, which can take on fractional values, using the framework of "jets without jets". In this paper, we perform the first analytic studies of fractional jet multiplicity Ñ jet in the context of e + e - collisions. We use fixed-order QCD to understand the Ñ jet cross section at order ? {/s 2}, and we introduce a candidate factorization theorem to capture certain higher-order effects. The resulting distributions have a hybrid jet algorithm/event shape behavior which agrees with parton shower Monte Carlo generators. The Ñ jet observable does not satisfy ordinary soft-collinear factorization, and the Ñ jet cross section exhibits a number of unique features, including the absence of collinear logarithms and the presence of soft logarithms that are purely non-global. Additionally, we find novel divergences connected to the energy sharing between emissions, which are reminiscent of rapidity divergences encountered in other applications. Given these interesting properties of fractional jet multiplicity, we advocate for future measurements and calculations of Ñ jet at hadron colliders like the LHC.

  8. The Aeroacoustics of Supersonic Coaxial Jets

    NASA Technical Reports Server (NTRS)

    Dahl, Milo D.

    1994-01-01

    Instability waves have been established as the dominant source of mixing noise radiating into the downstream arc of a supersonic jet when the waves have phase velocities that are supersonic relative to ambient conditions. Recent theories for supersonic jet noise have used the concepts of growing and decaying linear instability waves for predicting radiated noise. This analysis is extended to the prediction of noise radiation from supersonic coaxial jets. Since the analysis requires a known mean flow and the coaxial jet mean flow is not described easily in terms of analytic functions, a numerical prediction is made for its development. The Reynolds averaged, compressible, boundary layer equations are solved using a mixing length turbulence model. Empirical correlations are developed for the effects of velocity and temperature ratios and Mach number. Both normal and inverted velocity profile coaxial jets are considered. Comparisons with measurements for both single and coaxial jets show good agreement. The results from mean flow and stability calculations are used to predict the noise radiation from coaxial jets with different operating conditions. Comparisons are made between different coaxial jets and a single equivalent jet with the same total thrust, mass flow, and exit area. Results indicate that normal velocity profile jets can have noise reductions compared to the single equivalent jet. No noise reductions are found for inverted velocity profile jets operated at the minimum noise condition compared to the single equivalent jet. However, it is inferred that changes in area ratio may provide noise reduction benefits for inverted velocity profile jets.

  9. The First Calculation of Fractional Jets

    E-print Network

    Daniele Bertolini; Jesse Thaler; Jonathan R. Walsh

    2015-05-14

    In collider physics, jet algorithms are a ubiquitous tool for clustering particles into discrete jet objects. Event shapes offer an alternative way to characterize jets, and one can define a jet multiplicity event shape, which can take on fractional values, using the framework of "jets without jets". In this paper, we perform the first analytic studies of fractional jet multiplicity $\\tilde{N}_{\\rm jet}$ in the context of $e^+e^-$ collisions. We use fixed-order QCD to understand the $\\tilde{N}_{\\rm jet}$ cross section at order $\\alpha_s^2$, and we introduce a candidate factorization theorem to capture certain higher-order effects. The resulting distributions have a hybrid jet algorithm/event shape behavior which agrees with parton shower Monte Carlo generators. The $\\tilde{N}_{\\rm jet}$ observable does not satisfy ordinary soft-collinear factorization, and the $\\tilde{N}_{\\rm jet}$ cross section exhibits a number of unique features, including the absence of collinear logarithms and the presence of soft logarithms that are purely non-global. Additionally, we find novel divergences connected to the energy sharing between emissions, which are reminiscent of rapidity divergences encountered in other applications. Given these interesting properties of fractional jet multiplicity, we advocate for future measurements and calculations of $\\tilde{N}_{\\rm jet}$ at hadron colliders like the LHC.

  10. Sweeping Jet Actuator in a Quiescent Environment

    NASA Technical Reports Server (NTRS)

    Koklu, Mehti; Melton, Latunia P.

    2013-01-01

    This study presents a detailed analysis of a sweeping jet (fluidic oscillator) actuator. The sweeping jet actuator promises to be a viable flow control actuator candidate due to its simple, no moving part structure and its high momentum, spatially oscillating flow output. Hot-wire anemometer and particle image velocimetry measurements were carried out with an emphasis on understanding the actuator flow field in a quiescent environment. The time averaged, fluctuating, and instantaneous velocity measurements are provided. A modified actuator concept that incorporates high-speed solenoid valves to control the frequency of oscillation enabled phase averaged measurements of the oscillating jet. These measurements reveal that in a given oscillation cycle, the oscillating jet spends more time on each of the Coanda surfaces. In addition, the modified actuator generates four different types of flow fields, namely: a non oscillating downward jet, a non oscillating upward jet, a non oscillating straight jet, and an oscillating jet. The switching from an upward jet to a downward jet is accomplished by providing a single pulse from the solenoid valve. Once the flow is switched, the flow stays there until another pulse is received. The oscillating jet is compared with a non oscillating straight jet, which is a typical planar turbulent jet. The results indicate that the oscillating jet has a higher (5 times) spreading rate, more flow entrainment, and higher velocity fluctuations (equal to the mean velocity).

  11. Liquid Rainbow

    NSDL National Science Digital Library

    Mid-continent Research for Education and Learning (McREL)

    2004-01-01

    In this density activity, students determine the relative densities of five liquids and layer them atop one another in a straw. Directions for conducting the activity are included in addition to lists of the science process skills, complex reasoning strategies, and National Science Education Standards that relate to it. A brief explanation of the activity's science content and an assessment idea are also provided. This activity is part of a set called Whelmers that were designed to inspire students to think about science concepts.

  12. Liquid electrode

    DOEpatents

    Ekechukwu, A.A.

    1994-07-05

    A dropping electrolyte electrode is described for use in electrochemical analysis of non-polar sample solutions, such as benzene or cyclohexane. The liquid electrode, preferably an aqueous salt solution immiscible in the sample solution, is introduced into the solution in dropwise fashion from a capillary. The electrolyte is introduced at a known rate, thus, the droplets each have the same volume and surface area. The electrode is used in making standard electrochemical measurements in order to determine properties of non-polar sample solutions. 2 figures.

  13. DECELERATING RELATIVISTIC TWO-COMPONENT JETS

    SciTech Connect

    Meliani, Z.; Keppens, R., E-mail: Zakaria.Meliani@wis.kuleuven.b, E-mail: Rony.Keppens@wis.kuleuven.b [Centre for Plasma Astrophysics, K.U.Leuven (Belgium)

    2009-11-10

    Transverse stratification is a common intrinsic feature of astrophysical jets. There is growing evidence that jets in radio galaxies consist of a fast low-density outflow at the jet axis, surrounded by a slower, denser, extended jet. The inner and outer jet components then have a different origin and launching mechanism, making their effective inertia, magnetization, associated energy flux, and angular momentum content different as well. Their interface will develop differential rotation, where disruptions may occur. Here we investigate the stability of rotating, two-component relativistic outflows typical for jets in radio galaxies. For this purpose, we parametrically explore the long-term evolution of a transverse cross section of radially stratified jets numerically, extending our previous study where a single, purely hydrodynamic evolution was considered. We include cases with poloidally magnetized jet components, covering hydro and magnetohydrodynamic (MHD) models. With grid-adaptive relativistic MHD simulations, augmented with approximate linear stability analysis, we revisit the interaction between the two jet components. We study the influence of dynamically important poloidal magnetic fields, with varying contributions of the inner component jet to the total kinetic energy flux of the jet, on their non-linear azimuthal stability. We demonstrate that two-component jets with high kinetic energy flux and inner jet effective inertia which is higher than the outer jet effective inertia are subject to the development of a relativistically enhanced, rotation-induced Rayleigh-Taylor-type instability. This instability plays a major role in decelerating the inner jet and the overall jet decollimation. This novel deceleration scenario can partly explain the radio source dichotomy, relating it directly to the efficiency of the central engine in launching the inner jet component. The FRII/FRI transition could then occur when the relative kinetic energy flux of the inner to the outer jet grows beyond a certain threshold.

  14. Two-phase structure above hot surfaces in jet impingement boiling

    NASA Astrophysics Data System (ADS)

    Bogdanic, L.; Auracher, H.; Ziegler, F.

    2009-05-01

    Jet impingement boiling is very efficient in cooling of hot surfaces as a part of the impinging liquid evaporates. Several studies have been carried out to measure and correlate the heat transfer to impinging jets as a function of global parameters such as jet subcooling, jet velocity, nozzle size and distance to the surface, etc. If physically based mechanistic models are to be developed, studies on the fundamentals of two-phase dynamics near the hot surface are required. In the present study the vapor-liquid structures underneath a subcooled (20 K) planar (1 mm × 9 mm) water jet, impinging the heated plate vertically with a velocity of 0.4 m/s, were analyzed by means of a miniaturized optical probe. It has a tip diameter of app. 1.5 ?m and is moved toward the plate by a micrometer device. The temperature controlled experimental technique enabled steady-state experiments in all boiling regimes. The optical probe data provides information about the void fraction, the contact frequencies and the distribution of the vapor and liquid contact times as a function of the distance to the surface. The measured contact frequencies range from 40 Hz at the onset of nucleate boiling to nearly 20,000 Hz at the end of the transition boiling regime. Due to condensation in the subcooled jet vapor disappears at a distance to the surface of app. 1.2 mm in nucleate boiling. This vapor layer becomes smaller with increasing wall superheat. In film boiling a vapor film thickness of 8 ± 2 ?m was found.

  15. Measurement of the inclusive jet cross section in proton-antiproton collisions at the center-of-mass energy of 1.96 TeV

    SciTech Connect

    Voutilainen, Mikko Antero; /Helsinki Inst. of Phys. /Helsinki U. of Tech. /Nebraska U. /Saclay

    2008-07-01

    This thesis studies the high-energy collisions of protons and antiprotons. The data used in the measurement were collected during 2004-2005 with the D0 detector at the Tevatron Collider of the Fermi National Accelerator Laboratory and correspond to 0.7 fb{sup -1} of integrated luminosity. High energy hadron collisions usually produce collimated sprays of particles called jets. The energy of the jets is measured using a liquid Argon-Uranium calorimeter and the production angle is determined with the help of silicon microstrip and scintillating fiber trackers. The inclusive jet cross section in proton-antiproton collisions is measured as a function of jet transverse momentum p{sub T} in six bins of jet rapidity at the center-of-mass energy {radical}s = 1.96 TeV. The measurement covers jet transerve momenta from 50 GeV up to 600 GeV and jet rapidities up to |y| = 2.4. The data are collected using a set of seven single jet triggers. Event and jet cuts are applied to remove non-physical backgrounds and cosmic-ray interactions. The data are corrected for jet energy calibration, cut and trigger efficiencies and finite jet p{sub T} resolution. The corrections are determined from data and the methods are tested with Monte Carlo simulation. The main experimental challenges in the measurement are the calibration of jet energies and the determination of the jet p{sub T} resolution. New methods are developed for the jet energy calibration that take into account physical differences between the {gamma}+jet and dijet calibration samples arising from quark and gluon jet differences. The uncertainty correlations are studied and provided as a set of uncertainty sources. The production of particle jets in hadron collisions is described by the theory of quantum chromodynamics (QCD). When the transverse jet momentum is large, the contributions from long-distance physics processes are small and the production rates of jets can be predicted by perturbative QCD. The inclusive jet cross section in p{bar p} collisions at large p{sub T} is directly sensitive to the strong coupling constant ({alpha}{sub s}) and the parton distribution functions (PDFs) of the proton. This measurement can be used to constrain the PDFs, in particular the gluon PDF at high proton momentum fraction x, and to look for quark substructure at the TeV scale. The data are compared to the theory predictions with perturbative QCD in the next-to-leading order precision and a good agreement between data and theory is observed.

  16. Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC

    NASA Astrophysics Data System (ADS)

    Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian; Wanotayaroj, Chaowaroj

    2015-02-01

    Jets with a large radius R ? 1 and grooming algorithms are widely used to fully capture the decay products of boosted heavy particles at the Large Hadron Collider (LHC). Unlike most discriminating variables used in such studies, the jet radius is usually not optimized for specific physics scenarios. This is because every jet configuration must be calibrated, insitu, to account for detector response and other experimental effects. One solution to enhance the availability of large- R jet configurations used by the LHC experiments is jet re-clustering. Jet re-clustering introduces an intermediate scale r < R at which jets are calibrated and used as the inputs to reconstruct large radius jets. In this paper we systematically study and propose new jet re-clustering configurations and show that re-clustered large radius jets have essentially the same jet mass performance as large radius groomed jets. Jet re-clustering has the benefit that no additional large-R calibration is necessary, allowing the re-clustered large radius parameter to be optimized in the context of specific precision measurements or searches for new physics.

  17. Liquid phase chromatography on microchips.

    PubMed

    Kutter, Jörg P

    2012-01-20

    Over the past twenty years, the field of microfluidics has emerged providing one of the main enabling technologies to realize miniaturized chemical analysis systems, often referred to as micro-Total Analysis Systems (uTAS), or, more generally, Lab-on-a-Chip Systems (LOC) [1,2]. While microfluidics was driven forward a lot from the engineering side, especially with respect to ink jet and dispensing technology, the initial push and interest from the analytical chemistry community was through the desire to develop miniaturized sensors, detectors, and, very early on, separation systems. The initial almost explosive development of, in particular, chromatographic separation systems on microchips, has, however, slowed down in recent years. This review takes a closer, critical look at how liquid phase chromatography has been implemented in miniaturized formats over the past several years, what is important to keep in mind when developing or working with separations in a miniaturized format, and what challenges and pitfalls remain. PMID:22071425

  18. Vorticity Dynamics in Actuated Transverse Jets

    NASA Astrophysics Data System (ADS)

    Schlegel, Fabrice; Ghoniem, Ahmed F.

    2011-11-01

    Transverse jets are important to various industrial applications (film cooling, primary or dilution jets in gas turbines). Our previous results on the impact of the boundary layer detachment on the jet evolution show the sensibility of the overall jet dynamics to the near-nozzle conditions. Small perturbations at the nozzle exit are thus expected to act as powerful tools for control of the jet trajectory, its spanwise spreading, and its mixing properties. In this study, we demonstrate actuation strategies that manipulate the jet via nozzle edge perturbations, helical perturbations and the addition of delta-tabs at the nozzle exit.

  19. Role of shear-thinning on the dynamics of rinsing flow by an impinging jet

    NASA Astrophysics Data System (ADS)

    Walker, Travis W.; Hsu, Tienyi T.; Frank, Curtis W.; Fuller, Gerald G.

    2012-09-01

    Using a jet of one fluid to ablate a second liquid that coats a planar substrate produces a variety of interesting flow structures. These rinsing flows can create alternating layers of jet and coating fluids, creating difficulties in imaging the resulting radial hydraulic jumps for qualitative and quantitative data extraction. This study is an extension of the work done by Hsu et al. ["Role of fluid elasticity on the dynamics of rinsing flow by an impinging jet," Phys. Fluids. 23, 033101 (2011), 10.1063/1.3567215] and presents a method to reveal the positions of the free surfaces in rinsing flows as well as exploring the role of shear thinning in this flow process. Following the previous work, we used an impinging jet of water to rinse coating fluids of varying rheologies to understand the flow structures during the transient growth of the resulting hydraulic jumps, observing rheological dependencies on the jump magnitude and velocity and overall topography. While many instabilities have been shown to arise during rinsing flows, the flow profile strongly depends on the local viscosity ratio of the jet fluid to the coating fluid. Four classes of test liquids, each having approximately equal low-shear viscosities, have been chosen for this study: a Newtonian solution, a shear-thinning and elastic polymer solution, a Boger fluid (an elastic fluid with constant shear viscosity), and a shear-thinning but inelastic colloid suspension. The shear-thinning of the coating liquid is shown to affect the overall velocity of the radial growth and the geometry of the hydraulic jumps associated with both liquids. To confirm that the local shear viscosity controls many of the observed phenomena, experiments on Newtonian fluids having various shear viscosities are also presented.

  20. Guidance Document Cryogenic Liquids

    E-print Network

    are liquid nitrogen, liquid argon and liquid helium. The different cryogens become liquids under different oxygen could produce an oxygen-rich atmosphere which could accelerate combustion of other materials cryogenic liquid. But materials such as carbon steel, plastic and rubber become brittle and may fracture