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Sample records for large subsonic transports

  1. The future of very large subsonic transports

    NASA Technical Reports Server (NTRS)

    Justice, R. Steven; Hays, Anthony P.; Parrott, Ed L.

    1996-01-01

    The Very Large Subsonic Transport (VLST) is a multi-use commercial passenger, commercial cargo, and military airlifter roughly 50% larger than the current Lockheed C-5 and Boeing 747. Due to the large size and cost of the VLST, it is unlikely that the commercial market can support more than one aircraft production line, while declining defense budgets will not support a dedicated military VLST. A successful VLST must therefore meet airline requirements for more passenger and cargo capacity on congested routes into slot-limited airports and also provide a cost effective heavy airlift capacity to support the overseas deployment of US military forces. A successful VLST must satisfy three key missions: commercial passenger service with nominal seating capacity at a minimum of 650 passengers with a range capability of 7,000 to 10,000 miles; commercial air cargo service for containerized cargo to support global manufacturing of high value added products, 'just-in-time' parts delivery, and the general globalization of trade; and military airlift with adequate capacity to load current weapon systems, with minimal break-down, over global ranges (7,000 to 10,000 miles) required to reach the operational theater without need of overseas bases and midair refueling. The development of the VLST poses some technical issues specific to large aircraft, but also key technologies applicable to a wide range of subsonic transport aircraft. Key issues and technologies unique to the VLST include: large composite structures; dynamic control of a large, flexible structure; aircraft noise requirements for aircraft over 850,000 pounds; and increased aircraft separation due to increased wake vortex generation. Other issues, while not unique to the VLST, will critically impact the ability to build an efficient and affordable aircraft include: active control systems: Fly-By-Light/Power-By-Wire (FBL/PBW); high lift systems; flight deck associate systems; laminar flow; emergency egress; and

  2. Advanced Configurations for Very Large Subsonic Transport Airplanes

    NASA Technical Reports Server (NTRS)

    McMasters, John H.; Paisley, David J.; Hubert, Richard J.; Kroo, Ilan; Bofah, Kwasi K.; Sullivan, John P.; Drela, Mark

    1996-01-01

    Recent aerospace industry interest in developing a subsonic commercial transport airplane with 50 percent greater passenger capacity than the largest existing aircraft in this category (the Boeing 747-400 with approximately 400-450 seats) has generated a range of proposals based largely on the configuration paradigm established nearly 50 years ago with the Boeing B-47 bomber. While this basic configuration paradigm has come to dominate subsonic commercial airplane development since the advent of the Boeing 707/Douglas DC-8 in the mid-1950's, its extrapolation to the size required to carry more than 600-700 passengers raises several questions. To explore these and a number of related issues, a team of Boeing, university, and NASA engineers was formed under the auspices of the NASA Advanced Concepts Program. The results of a Research Analysis focused on a large, unconventional transport airplane configuration for which Boeing has applied for a patent are the subject of this report. It should be noted here that this study has been conducted independently of the Boeing New Large Airplane (NLA) program, and with the exception of some generic analysis tools which may be common to this effort and the NLA (as will be described later), no explicit Boeing NLA data other than that published in the open literature has been used in the conduct of the study reported here.

  3. Takeoff certification considerations for large subsonic and supersonic transport airplanes using the Ames flight simulator for advanced aircraft

    NASA Technical Reports Server (NTRS)

    Snyder, C. T.; Drinkwater, F. J., III; Fry, E. B.; Forrest, R. D.

    1973-01-01

    Data for use in development of takeoff airworthiness standards for new aircraft designs such as the supersonic transport (SST) and the large wide-body subsonic jet transport are provided. An advanced motion simulator was used to compare the performance and handling characteristics of three representative large jet transports during specific flight certification tasks. Existing regulatory constraints and methods for determining rotation speed were reviewed, and the effects on takeoff performance of variations in rotation speed, pitch attitude, and pitch attitude rate during the rotation maneuver were analyzed. A limited quantity of refused takeoff information was obtained. The aerodynamics, wing loading, and thrust-to-weight ratio of the subject SST resulted in takeoff speeds limited by climb (rather than lift-off) considerations. Take-off speeds based on U.S. subsonic transport requirements were found unacceptable because of the criticality of rotation-abuse effects on one-engine-inoperative climb performance. Adequate safety margin was provided by takeoff speeds based on proposed Anglo-French supersonic transport (TSS) criteria, with the limiting criterion being that takeoff safety speed be at least 1.15 times the one-engine-inoperative zero-rate-of-climb speed. Various observations related to SST certification are presented.

  4. A Probabilistic Assessment of NASA Ultra-Efficient Engine Technologies for a Large Subsonic Transport

    NASA Technical Reports Server (NTRS)

    Tong, Michael T.; Jones, Scott M.; Arcara, Philip C., Jr.; Haller, William J.

    2004-01-01

    NASA's Ultra Efficient Engine Technology (UEET) program features advanced aeropropulsion technologies that include highly loaded turbomachinery, an advanced low-NOx combustor, high-temperature materials, intelligent propulsion controls, aspirated seal technology, and an advanced computational fluid dynamics (CFD) design tool to help reduce airplane drag. A probabilistic system assessment is performed to evaluate the impact of these technologies on aircraft fuel burn and NOx reductions. A 300-passenger aircraft, with two 396-kN thrust (85,000-pound) engines is chosen for the study. The results show that a large subsonic aircraft equipped with the UEET technologies has a very high probability of meeting the UEET Program goals for fuel-burn (or equivalent CO2) reduction (15% from the baseline) and LTO (landing and takeoff) NOx reductions (70% relative to the 1996 International Civil Aviation Organization rule). These results are used to provide guidance for developing a robust UEET technology portfolio, and to prioritize the most promising technologies required to achieve UEET program goals for the fuel-burn and NOx reductions.

  5. Overview of NASA Electrified Aircraft Propulsion Research for Large Subsonic Transports

    NASA Technical Reports Server (NTRS)

    Jansen, Ralph H.; Bowman, Cheryl; Jankovsky, Amy; Dyson, Rodger; Felder, James

    2017-01-01

    NASA is investing in Electrified Aircraft Propulsion (EAP) research as part of the portfolio to improve the fuel efficiency, emissions, and noise levels in commercial transport aircraft. Turboelectric, partially turboelectric, and hybrid electric propulsion systems are the primary EAP configurations being evaluated for regional jet and larger aircraft. The goal is to show that one or more viable EAP concepts exist for narrow body aircraft and mature tall-pole technologies related to those concepts. A summary of the aircraft system studies, technology development, and facility development is provided. The leading concept for mid-term (2035) introduction of EAP for a single aisle aircraft is a tube and wing, partially turbo electric configuration (STARC-ABL), however other viable configurations exist. Investments are being made to raise the TRL level of light weight, high efficiency motors, generators, and electrical power distribution systems as well as to define the optimal turbine and boundary layer ingestion systems for a mid-term tube and wing configuration. An electric aircraft power system test facility (NEAT) is under construction at NASA Glenn and an electric aircraft control system test facility (HEIST) is under construction at NASA Armstrong. The correct building blocks are in place to have a viable, large plane EAP configuration tested by 2025 leading to entry into service in 2035 if the community chooses to pursue that goal.

  6. Incorporating biplane wing theory into a large, subsonic, all-cargo transport

    NASA Technical Reports Server (NTRS)

    Zyskowski, Michael K.

    1994-01-01

    If the air-cargo market increases at the pace predicted, a new conceptual aircraft will be demanded to meet the needs of the air-cargo industry. Furthermore, it has been found that not only should this aircraft be optimized to carry the intermodal containers used by the current shipping industry, but it should also be be able to operate at existing airports. The best solution to these problems is a configuration incorporating a bi-wing planform, which has resulted in significant improvements over the monoplane in lift/drag, weight reduction, and span reduction. The future of the air-cargo market, biplane theory, wind tunnel tests, and a comparison of the aerodynamic characteristics of the biplane and monoplane are discussed. The factors pertaining to a biplane cargo transport are then examined, resulting in biplane geometric parameters.

  7. Propulsion technology for an advanced subsonic transport

    NASA Technical Reports Server (NTRS)

    Beheim, M. A.; Antl, R. J.; Povolny, J. H.

    1972-01-01

    Engine design studies for future subsonic commercial transport aircraft were conducted in parallel with airframe studies. These studies surveyed a broad distribution of design variables, including aircraft configuration, payload, range, and speed, with particular emphasis on reducing noise and exhaust emissions without severe economic and performance penalties. The results indicated that an engine for an advanced transport would be similar to the currently emerging turbofan engines. Application of current technology in the areas of noise suppression and combustors imposed severe performance and economic penalties.

  8. NASA's Subsonic Jet Transport Noise Reduction Research

    NASA Technical Reports Server (NTRS)

    Powell, Clemans A.; Preisser, John S.

    2000-01-01

    Although new jet transport airplanes in today s fleet are considerably quieter than the first jet transports introduced about 40 years ago, airport community noise continues to be an important environmental issue. NASA s Advanced Subsonic Transport (AST) Noise Reduction program was begun in 1994 as a seven-year effort to develop technology to reduce jet transport noise 10 dB relative to 1992 technology. This program provides for reductions in engine source noise, improvements in nacelle acoustic treatments, reductions in the noise generated by the airframe, and improvements in the way airplanes are operated in the airport environs. These noise reduction efforts will terminate at the end of 2001 and it appears that the objective will be met. However, because of an anticipated 3-8% growth in passenger and cargo operations well into the 21st Century and the slow introduction of new the noise reduction technology into the fleet, world aircraft noise impact will remain essentially constant until about 2020 to 2030 and thereafter begin to rise. Therefore NASA has begun planning with the Federal Aviation Administration, industry, universities and environmental interest groups in the USA for a new noise reduction initiative to provide technology for significant further reductions.

  9. Tabulated pressure measurements on a large subsonic transport model airplane with high bypass ratio, powered, fan jet engines

    NASA Technical Reports Server (NTRS)

    Flechner, S. G.; Patterson, J. C., Jr.

    1972-01-01

    An experimental wind-tunnel investigation to determine the aerodynamic interference and the jet-wake interference associated with the wing, pylon, and high-bypass-ratio, powered, fan-jet model engines has been conducted on a typical high-wing logistics transport airplane configuration. Pressures were measured on the wing and pylons and on the surfaces of the engine fan cowl, turbine cowl, and plug. Combinations of wing, pylons, engines, and flow-through nacelles were tested, and the pressure coefficients are presented in tabular form. Tests were conducted at Mach numbers from 0.700 to 0.825 and angles of attack from -2 to 4 deg.

  10. Large-Eddy Simulation of Subsonic Jets

    NASA Astrophysics Data System (ADS)

    Vuorinen, Ville; Wehrfritz, Armin; Yu, Jingzhou; Kaario, Ossi; Larmi, Martti; Boersma, Bendiks Jan

    2011-12-01

    The present study deals with development and validation of a fully explicit, compressible Runge-Kutta-4 (RK4) Navier-Stokes solver in the opensource CFD programming environment OpenFOAM. The background motivation is to shift towards explicit density based solution strategy and thereby avoid using the pressure based algorithms which are currently proposed in the standard OpenFOAM release for Large-Eddy Simulation (LES). This shift is considered necessary in strongly compressible flows when Ma > 0.5. Our application of interest is related to the pre-mixing stage in direct injection gas engines where high injection pressures are typically utilized. First, the developed flow solver is discussed and validated. Then, the implementation of subsonic inflow conditions using a forcing region in combination with a simplified nozzle geometry is discussed and validated. After this, LES of mixing in compressible, round jets at Ma = 0.3, 0.5 and 0.65 are carried out. Respectively, the Reynolds numbers of the jets correspond to Re = 6000, 10000 and 13000. Results for two meshes are presented. The results imply that the present solver produces turbulent structures, resolves a range of turbulent eddy frequencies and gives also mesh independent results within satisfactory limits for mean flow and turbulence statistics.

  11. The Liquid Hydrogen Option for the Subsonic Transport: A status report

    NASA Technical Reports Server (NTRS)

    Korycinski, P. F.

    1977-01-01

    Continued subsonic air transport design studies include the option for a liquid hydrogen fuel system as an aircraft fuel conservation measure. Elements of this option discussed include: (1) economical production of hydrogen; (2) efficient liquefaction of hydrogen; (3) materials for long service life LH2 fuel tanks; (4) insulation materials; (5) LH2 fuel service and installations at major air terminals; (6) assessment of LH2 hazards; and (7) the engineering definition of an LH2 fuel system for a large subsonic passenger air transport.

  12. Follow-On Technology Requirement Study for Advanced Subsonic Transport

    NASA Technical Reports Server (NTRS)

    Wendus, Bruce E.; Stark, Donald F.; Holler, Richard P.; Funkhouser, Merle E.

    2003-01-01

    A study was conducted to define and assess the critical or enabling technologies required for a year 2005 entry into service (EIS) engine for subsonic commercial aircraft, with NASA Advanced Subsonic Transport goals used as benchmarks. The year 2005 EIS advanced technology engine is an Advanced Ducted Propulsor (ADP) engine. Performance analysis showed that the ADP design offered many advantages compared to a baseline turbofan engine. An airplane/ engine simulation study using a long range quad aircraft quantified the effects of the ADP engine on the economics of typical airline operation. Results of the economic analysis show the ADP propulsion system provides a 6% reduction in direct operating cost plus interest, with half the reduction resulting from reduced fuel consumption. Critical and enabling technologies for the year 2005 EIS ADP were identified and prioritized.

  13. Study of LH2 fueled subsonic passenger transport aircraft

    NASA Technical Reports Server (NTRS)

    Brewer, G. D.; Morris, R. E.

    1976-01-01

    The potential of using liquid hydrogen as fuel in subsonic transport aircraft was investigated to explore an expanded matrix of passenger aircraft sizes. Aircraft capable of carrying 130 passengers 2,780 km (1500 n.mi.); 200 passengers 5,560 km (3000 n.mi.); and 400 passengers on a 9,265 km (5000 n.mi.) radius mission, were designed parametrically. Both liquid hydrogen and conventionally fueled versions were generated for each payload/range in order that comparisons could be made. Aircraft in each mission category were compared on the basis of weight, size, cost, energy utilization, and noise.

  14. NASA Noise Reduction Program for Advanced Subsonic Transports

    NASA Technical Reports Server (NTRS)

    Stephens, David G.; Cazier, F. W., Jr.

    1995-01-01

    Aircraft noise is an important byproduct of the world's air transportation system. Because of growing public interest and sensitivity to noise, noise reduction technology is becoming increasingly important to the unconstrained growth and utilization of the air transportation system. Unless noise technology keeps pace with public demands, noise restrictions at the international, national and/or local levels may unduly constrain the growth and capacity of the system to serve the public. In recognition of the importance of noise technology to the future of air transportation as well as the viability and competitiveness of the aircraft that operate within the system, NASA, the FAA and the industry have developed noise reduction technology programs having application to virtually all classes of subsonic and supersonic aircraft envisioned to operate far into the 21st century. The purpose of this paper is to describe the scope and focus of the Advanced Subsonic Technology Noise Reduction program with emphasis on the advanced technologies that form the foundation of the program.

  15. Evaluation of viscous drag reduction schemes for subsonic transports

    NASA Technical Reports Server (NTRS)

    Marino, A.; Economos, C.; Howard, F. G.

    1975-01-01

    The results are described of a theoretical study of viscous drag reduction schemes for potential application to the fuselage of a long-haul subsonic transport aircraft. The schemes which were examined included tangential slot injection on the fuselage and various synergetic combinations of tangential slot injection and distributed suction applied to wing and fuselage surfaces. Both passive and mechanical (utilizing turbo-machinery) systems were examined. Overall performance of the selected systems was determined at a fixed subsonic cruise condition corresponding to a flight Mach number of free stream M = 0.8 and an altitude of 11,000 m. The nominal aircraft to which most of the performance data was referenced was a wide-body transport of the Boeing 747 category. Some of the performance results obtained with wing suction are referenced to a Lockheed C-141 Star Lifter wing section. Alternate designs investigated involved combinations of boundary layer suction on the wing surfaces and injection on the fuselage, and suction and injection combinations applied to the fuselage only.

  16. Advanced subsonic long-haul transport terminal area compatibility study. Volume 1: Compatibility assessment

    NASA Technical Reports Server (NTRS)

    1974-01-01

    An analysis was made to identify airplane research and technology necessary to ensure advanced transport aircraft the capability of accommodating forecast traffic without adverse impact on airport communities. Projections were made of the delay, noise, and emissions impact of future aircraft fleets on typical large urban airport. Design requirements, based on these projections, were developed for an advanced technology, long-haul, subsonic transport. A baseline aircraft was modified to fulfill the design requirements for terminal area compatibility. Technical and economic comparisons were made between these and other aircraft configured to support the study.

  17. Power-by-Wire Development and Demonstration for Subsonic Civil Transport

    NASA Technical Reports Server (NTRS)

    1996-01-01

    During the last decade, three significant studies by the Lockheed Martin Corporation, the NASA Lewis Research Center, and McDonnell Douglas Corporation have clearly shown operational, weight, and cost advantages for commercial subsonic transport aircraft that use all-electric or more-electric technologies in the secondary electric power systems. Even though these studies were completed on different aircraft, used different criteria, and applied a variety of technologies, all three have shown large benefits to the aircraft industry and to the nation's competitive position. The Power-by-Wire (PBW) program is part of the highly reliable Fly-By-Light/Power-By-Wire (FBL/PBW) Technology Program, whose goal is to develop the technology base for confident application of integrated FBL/PBW systems for transport aircraft. This program is part of the NASA aeronautics strategic thrust in subsonic aircraft/national airspace (Thrust 1) to "develop selected high-leverage technologies and explore new means to ensure the competitiveness of U.S. subsonic aircraft and to enhance the safety and productivity of the national aviation system" (The Aeronautics Strategic Plan). Specifically, this program is an initiative under Thrust 1, Key Objective 2, to "develop, in cooperation with U.S. industry, selected high-payoff technologies that can enable significant improvements in aircraft efficiency and cost."

  18. Technologies and Concepts for Reducing the Fuel Burn of Subsonic Transport Aircraft

    NASA Technical Reports Server (NTRS)

    Nickol, Craig L.

    2012-01-01

    There are many technologies under development that have the potential to enable large fuel burn reductions in the 2025 timeframe for subsonic transport aircraft relative to the current fleet. This paper identifies a potential technology suite and analyzes the fuel burn reduction potential of these technologies when integrated into advanced subsonic transport concepts. Advanced tube-and-wing concepts are developed in the single aisle and large twin aisle class, and a hybrid-wing-body concept is developed for the large twin aisle class. The resulting fuel burn reductions for the advanced tube-and-wing concepts range from a 42% reduction relative to the 777-200 to a 44% reduction relative to the 737-800. In addition, the hybrid-wingbody design resulted in a 47% fuel burn reduction relative to the 777-200. Of course, to achieve these fuel burn reduction levels, a significant amount of technology and concept maturation is required between now and 2025. A methodology for capturing and tracking concept maturity is also developed and presented in this paper.

  19. Advanced subsonic transport approach noise: The relative contribution of airframe noise

    NASA Technical Reports Server (NTRS)

    Willshire, William L., Jr.; Garber, Donald P.

    1992-01-01

    With current engine technology, airframe noise is a contributing source for large commercial aircraft on approach, but not the major contributor. With the promise of much quieter jet engines with the planned new generation of high-by-pass turbofan engines, airframe noise has become a topic of interest in the advanced subsonic transport research program. The objective of this paper is to assess the contribution of airframe noise relative to the other aircraft noise sources on approach. The assessment will be made for a current technology large commercial transport aircraft and for an envisioned advanced technology aircraft. NASA's Aircraft Noise Prediction Program (ANOPP) will be used to make total aircraft noise predictions for these two aircraft types. Predicted noise levels and areas of noise contours will be used to determine the relative importance of the contributing approach noise sources. The actual set-up decks used to make the ANOPP runs for the two aircraft types are included in appendixes.

  20. Assessment of the Performance Potential of Advanced Subsonic Transport Concepts for NASA's Environmentally Responsible Aviation Project

    NASA Technical Reports Server (NTRS)

    Nickol, Craig L.; Haller, William J.

    2016-01-01

    NASA's Environmentally Responsible Aviation (ERA) project has matured technologies to enable simultaneous reductions in fuel burn, noise, and nitrogen oxide (NOx) emissions for future subsonic commercial transport aircraft. The fuel burn reduction target was a 50% reduction in block fuel burn (relative to a 2005 best-in-class baseline aircraft), utilizing technologies with an estimated Technology Readiness Level (TRL) of 4-6 by 2020. Progress towards this fuel burn reduction target was measured through the conceptual design and analysis of advanced subsonic commercial transport concepts spanning vehicle size classes from regional jet (98 passengers) to very large twin aisle size (400 passengers). Both conventional tube-and-wing (T+W) concepts and unconventional (over-wing-nacelle (OWN), hybrid wing body (HWB), mid-fuselage nacelle (MFN)) concepts were developed. A set of propulsion and airframe technologies were defined and integrated onto these advanced concepts which were then sized to meet the baseline mission requirements. Block fuel burn performance was then estimated, resulting in reductions relative to the 2005 best-in-class baseline performance ranging from 39% to 49%. The advanced single-aisle and large twin aisle T+W concepts had reductions of 43% and 41%, respectively, relative to the 737-800 and 777-200LR aircraft. The single-aisle OWN concept and the large twin aisle class HWB concept had reductions of 45% and 47%, respectively. In addition to their estimated fuel burn reduction performance, these unconventional concepts have the potential to provide significant noise reductions due, in part, to engine shielding provided by the airframe. Finally, all of the advanced concepts also have the potential for significant NOx emissions reductions due to the use of advanced combustor technology. Noise and NOx emissions reduction estimates were also generated for these concepts as part of the ERA project.

  1. Formal representation of the requirements for an Advanced Subsonic Civil Transport (ASCT) flight control system

    NASA Technical Reports Server (NTRS)

    Frincke, Deborah; Wolber, Dave; Fisher, Gene; Cohen, Gerald C.; Mclees, R. E.

    1992-01-01

    A partial requirement specification for an Advanced Subsonic Civil Transport (ASCT) Flight Control System is described. The example was adopted from requirements given in a NASA Contractor report. The language used to describe the requirements, Requirements Specification Language (RSL), is described in a companion document.

  2. Steady Subsonic Ideal Flows Through an Infinitely Long Nozzle with Large Vorticity

    NASA Astrophysics Data System (ADS)

    Du, Lili; Xie, Chunjing; Xin, Zhouping

    2014-05-01

    In this paper, the existence, uniqueness, and far field behavior of a class of subsonic flows with large vorticity for the steady Euler equations in infinitely long nozzles are established. More precisely, for any given convex horizontal velocity of incoming flow in the upstream, there exists a critical value m cr , if the mass flux is larger than m cr , then there exists a unique smooth subsonic Euler flow through the infinitely long nozzle. This well-posedness result is proved by a new observation for the method developed in Xie and Xin (SIAM J Math Anal 42:751-784, 2010) to deal with the Euler system. Furthermore, the optimal convergence rates of the subsonic flows at far fields are obtained via the maximum principle and an elaborate choice of the comparison functions.

  3. Comparison of solutions to bi-Maxwellian and Maxwellian transport equations for subsonic flows. [in terrestrial ionosphere

    NASA Technical Reports Server (NTRS)

    Demars, H. G.; Schunk, R. W.

    1987-01-01

    Conditions corresponding to the steady state subsonic flow of a fully ionized electron-proton plasma in the terrestrial ionosphere are presently characterized by systematically comparing the solutions to the bi-Maxwellian-based 16-moment and Maxwellian-based 13-moment transport equations. The former can account for large temperature anisotropies and the flow of both parallel and perpendicular thermal energy, while the latter account for small temperature anisotropies and only a total heat flow. The comparison is conducted for 2000-10,000 K lower boundary temperatures and 1-4-K/km temperature gradients, over the 1500-13,000-km altitude range.

  4. Study of methane fuel for subsonic transport aircraft

    NASA Technical Reports Server (NTRS)

    Carson, L. K.; Davis, G. W.; Versaw, E. F.; Cunnington, G. R., Jr.; Daniels, E. J.

    1980-01-01

    The cost and performance were defined for commercial transport using liquid methane including its fuel system and the ground facility complex required for the processing and storage of methane. A cost and performance comparison was made with Jet A and hydrogen powered aircraft of the same payload and range capability. Extensive design work was done on cryogenic fuel tanks, insulation systems as well as the fuel system itself. Three candidate fuel tank locations were evaluated, i.e., fuselage tanks, wing tanks or external pylon tanks.

  5. Aviation safety and automation technology for subsonic transports

    NASA Technical Reports Server (NTRS)

    Albers, James A.

    1991-01-01

    Discussed here are aviation safety human factors and air traffic control (ATC) automation research conducted at the NASA Ames Research Center. Research results are given in the areas of flight deck and ATC automations, displays and warning systems, crew coordination, and crew fatigue and jet lag. Accident investigation and an incident reporting system that is used to guide the human factors research is discussed. A design philosophy for human-centered automation is given, along with an evaluation of automation on advanced technology transports. Intelligent error tolerant systems such as electronic checklists are discussed along with design guidelines for reducing procedure errors. The data on evaluation of Crew Resource Management (CRM) training indicates highly significant positive changes in appropriate flight deck behavior and more effective use of available resources for crew members receiving the training.

  6. Subsonic Aerodynamic Assessment of Vortex Flow Management Devices on a High-Speed Civil Transport Configuration

    NASA Technical Reports Server (NTRS)

    Campbell, Bryan A.; Applin, Zachary T.; Kemmerly, Guy T.

    1999-01-01

    An experimental investigation of the effects of leading-edge vortex management devices on the subsonic performance of a high-speed civil transport (HSCT) configuration was conducted in the Langley 14- by 22-Foot Subsonic Tunnel. Data were obtained over a Mach number range of 0.14 to 0.27, with corresponding chord Reynolds numbers of 3.08 x 10 (sup 6) to 5.47 x 10 (sup 6). The test model was designed for a cruise Mach number of 2.7. During the subsonic high-lift phase of flight, vortical flow dominates the upper surface flow structure, and during vortex breakdown, this flow causes adverse pitch-up and a reduction of usable lift. The experimental results showed that the beneficial effects of small leading-edge vortex management devices located near the model reference center were insufficient to substantially affect the resulting aerodynamic forces and moments. However, devices located at or near the wiring apex region demonstrated potential for pitch control with little effect on overall lift.

  7. Guidelines for Computing Longitudinal Dynamic Stability Characteristics of a Subsonic Transport

    NASA Technical Reports Server (NTRS)

    Thompson, Joseph R.; Frank, Neal T.; Murphy, Patrick C.

    2010-01-01

    A systematic study is presented to guide the selection of a numerical solution strategy for URANS computation of a subsonic transport configuration undergoing simulated forced oscillation about its pitch axis. Forced oscillation is central to the prevalent wind tunnel methodology for quantifying aircraft dynamic stability derivatives from force and moment coefficients, which is the ultimate goal for the computational simulations. Extensive computations are performed that lead in key insights of the critical numerical parameters affecting solution convergence. A preliminary linear harmonic analysis is included to demonstrate the potential of extracting dynamic stability derivatives from computational solutions.

  8. Trim and Structural Optimization of Subsonic Transport Wings Using Nonconventional Aeroelastic Tailoring

    NASA Technical Reports Server (NTRS)

    Stanford, Bret K.; Jutte, Christine V.

    2014-01-01

    Several minimum-mass aeroelastic optimization problems are solved to evaluate the effectiveness of a variety of novel tailoring schemes for subsonic transport wings. Aeroelastic strength and panel buckling constraints are imposed across a variety of trimmed maneuver loads. Tailoring with metallic thickness variations, functionally graded materials, composite laminates, tow steering, and distributed trailing edge control effectors are all found to provide reductions in structural wing mass with varying degrees of success. The question as to whether this wing mass reduction will offset the increased manufacturing cost is left unresolved for each case.

  9. Study of the application of hydrogen fuel to long-range subsonic transport aircraft, volume 2

    NASA Technical Reports Server (NTRS)

    Brewer, G. D.; Morris, R. E.; Lange, R. H.; Moore, J. W.

    1975-01-01

    The feasibility, practicability, and potential advantages/disadvantages of using liquid hydrogen as fuel in long range, subsonic transport aircraft of advanced design were studied. Both passenger and cargo-type aircraft were investigated. To provide a valid basis for comparison, conventional hydrocarbon (Jet A) fueled aircraft were designed to perform identical missions using the same advanced technology and meeting the same operational constraints. The liquid hydrogen and Jet A fueled aircraft were compared on the basis of weight, size, energy utilization, cost, noise, emissions, safety, and operational characteristics. A program of technology development was formulated.

  10. Evaluation of laminar flow control systems concepts for subsonic commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Pearce, W. E.

    1983-01-01

    An evaluation was made of laminar flow control (LFC) system concepts for subsonic commercial transport aircraft. Configuration design studies, performance analyses, fabrication development, structural testing, wind tunnel testing, and contamination-avoidance techniques were included. As a result of trade studies, a configuration with LFC on the upper wing surface only, utilizing an electron beam-perforated suction surface, and employing a retractable high-lift shield for contamination avoidance, was selected as the most practical LFC system. The LFC aircraft was then compared with an advanced turbulent aircraft designed for the same mission. This comparison indicated significant fuel savings and reduced direct operating cost benefits would result from using LFC.

  11. Evaluation of laminar flow control systems for subsonic commercial transport aircraft: Executive summary

    NASA Technical Reports Server (NTRS)

    Pearce, W. E.

    1982-01-01

    An evaluation was made of laminar flow control (LFC) system concepts for subsonic commercial transport aircraft. Configuration design studies, performance analyses, fabrication development, structural testing, wind tunnel testing, and contamination-avoidance techniques were included. As a result of trade studies, a configuration with LFC on the upper wing surface only, utilizing an electron beam-perforated suction surface, and employing a retractable high-lift shield for contamination avoidance, was selected as the most practical LFC system. The LFC aircraft was then compared with an advanced turbulent aircraft designed for the same mission. This comparison indicated significant fuel savings.

  12. An example of requirements for Advanced Subsonic Civil Transport (ASCT) flight control system using structured techniques

    NASA Technical Reports Server (NTRS)

    Mclees, Robert E.; Cohen, Gerald C.

    1991-01-01

    The requirements are presented for an Advanced Subsonic Civil Transport (ASCT) flight control system generated using structured techniques. The requirements definition starts from initially performing a mission analysis to identify the high level control system requirements and functions necessary to satisfy the mission flight. The result of the study is an example set of control system requirements partially represented using a derivative of Yourdon's structured techniques. Also provided is a research focus for studying structured design methodologies and in particular design-for-validation philosophies.

  13. Evaluation of Laminar Flow Control System Concepts for Subsonic Commercial Transport Aircraft

    NASA Technical Reports Server (NTRS)

    Sturgeon, R. F.

    1980-01-01

    Alternatives in the design of laminar flow control (LFC) subsonic commerical transport aircraft for opeation in the 1980's period were studied. Analyses were conducted to select mission parameters and define optimum aircraft configurational parameters for the selected mission, defined by a passenger payload of 400 and a design range of 12, 038 km (6500 n mi). The baseline aircraft developed for this mission was used as a vehicle for the evaluation and development of alternative LFC system concepts. Alternatices in the areas of aerodynamics, structures and materials, LFC systems, leading-edge region cleaning, and integration of auxiliary systems were studied. Relative to a similarly-optimized advanced technology turbulent transport, the final LFC configuration is approximately equal in DOC but provides descreases of 8.2% in gross weight and 21.7% in fuel consumption.

  14. The development and evaluation of advanced technology laminar-flow-control subsonic transport aircraft

    NASA Technical Reports Server (NTRS)

    Sturgeon, R. F.

    1978-01-01

    A study was conducted to evaluate the technical and economic feasibility of applying laminar flow control (LFC) to the wings and empennage of long-range subsonic transport aircraft for initial operation in 1985. For a design mission range of 5500 n mi, advanced technology LFC and turbulent-flow aircraft were developed for a 200-passenger payload, and compared on the basis of production costs, direct operating costs, and fuel efficiency. Parametric analyses were conducted to establish optimum geometry, advanced system concepts were evaluated, and configuration variations maximizing the effectiveness of LFC were developed. The final comparisons include consideation of maintenance costs and procedures, manufacturing costs and procedures, and operational considerations peculiar to LFC aircraft.

  15. CFD Assessment of Aerodynamic Degradation of a Subsonic Transport Due to Airframe Damage

    NASA Technical Reports Server (NTRS)

    Frink, Neal T.; Pirzadeh, Shahyar Z.; Atkins, Harold L.; Viken, Sally A.; Morrison, Joseph H.

    2010-01-01

    A computational study is presented to assess the utility of two NASA unstructured Navier-Stokes flow solvers for capturing the degradation in static stability and aerodynamic performance of a NASA General Transport Model (GTM) due to airframe damage. The approach is to correlate computational results with a substantial subset of experimental data for the GTM undergoing progressive losses to the wing, vertical tail, and horizontal tail components. The ultimate goal is to advance the probability of inserting computational data into the creation of advanced flight simulation models of damaged subsonic aircraft in order to improve pilot training. Results presented in this paper demonstrate good correlations with slope-derived quantities, such as pitch static margin and static directional stability, and incremental rolling moment due to wing damage. This study further demonstrates that high fidelity Navier-Stokes flow solvers could augment flight simulation models with additional aerodynamic data for various airframe damage scenarios.

  16. Comparison of all-electric secondary power systems for civil subsonic transports

    NASA Technical Reports Server (NTRS)

    Renz, David D.

    1992-01-01

    Three separate studies have shown operational, weight, and cost advantages for commercial subsonic transport aircraft using an all-electric secondary power system. The first study in 1982 showed that all-electric secondary power systems produced the second largest benefit compared to four other technology upgrades. The second study in 1985 showed a 10 percent weight and fuel savings using an all-electric high frequency (20 kHz) secondary power system. The last study in 1991 showed a 2 percent weight savings using today's technology (400 Hz) in an all-electric secondary power system. This paper will compare the 20 kHz and 400 Hz studies, analyze the 2 to 10 percent difference in weight savings and comment on the common benefits of the all-electric secondary power system.

  17. Vehicle design considerations for active control application to subsonic transport aircraft

    NASA Technical Reports Server (NTRS)

    Hofmann, L. G.; Clement, W. F.

    1974-01-01

    The state of the art in active control technology is summarized. How current design criteria and airworthiness regulations might restrict application of this emerging technology to subsonic CTOL transports of the 1980's are discussed. Facets of active control technology considered are: (1) augmentation of relaxed inherent stability; (2) center-of-gravity control; (3) ride quality control; (4) load control; (5) flutter control; (6) envelope limiting, and (7) pilot interface with the control system. A summary and appraisal of the current state of the art, design criteria, and recommended practices, as well as a projection of the risk in applying each of these facets of active control technology is given. A summary of pertinent literature and technical expansions is included.

  18. The development and evaluation of advanced technology laminar-flow-control subsonic transport aircraft

    NASA Technical Reports Server (NTRS)

    Sturgeon, R. F.

    1978-01-01

    A study was conducted to evaluate the technical and economic feasibility of applying laminar flow control (LFC) to the wings and empennage of long-range subsonic transport aircraft for initial operation in 1985. For a design mission range of 5500 n mi, advanced technology LFC and turbulent-flow aircraft were developed for a 200-passenger payload, and compared on the basis of production costs, direct operating costs, and fuel efficiency. Parametric analyses were conducted to establish optimum geometry, advanced system concepts were evaluated, and configuration variations maximizing the effectiveness of LFC were developed. The final comparisons include consideation of maintenance costs and procedures, manufacturing costs and procedures, and operational considerations peculiar to LFC aircraft.

  19. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Program review

    NASA Technical Reports Server (NTRS)

    1986-01-01

    This report summarizes the Integrated Application of Active Controls (IAAC) Technology to an Advanced Subsonic Transport Project, established as one element of the NASA/Boeing Energy Efficient Transport Technology Program. The performance assessment showed that incorporating ACT into an airplane designed to fly approximately 200 passengers approximately 2,000 nmi could yield block fuel savings from 6 to 10 percent at the design range. The principal risks associated with incorporating these active control functions into a commercial airplane are those involved with the ACT system implementation. The Test and Evaluation phase of the IAAC Project focused on the design, fabrication, and test of a system that implemented pitch axis fly-by-wire, pitch axis augmentation, and wing load alleviation. The system was built to be flight worthy, and was planned to be experimentally flown on the 757. The system was installed in the Boeing Digital Avionics Flight Controls Laboratory (DAFCL), where open loop hardware and software tests, and a brief examination of a direct drive valve (DDV) actuation concept were accomplished. The IAAC Project has shown that ACT can be beneficially incorporated into a commercial transport airplane. Based on the results achieved during the testing phase, there appears to be no fundamental reason(s) that would preclude the commercial application of ACT, assuming an appropriate development effort is included.

  20. On the use of controls for subsonic transport performance improvement: Overview and future directions

    NASA Technical Reports Server (NTRS)

    Gilyard, Glenn; Espana, Martin

    1994-01-01

    Increasing competition among airline manufacturers and operators has highlighted the issue of aircraft efficiency. Fewer aircraft orders have led to an all-out efficiency improvement effort among the manufacturers to maintain if not increase their share of the shrinking number of aircraft sales. Aircraft efficiency is important in airline profitability and is key if fuel prices increase from their current low. In a continuing effort to improve aircraft efficiency and develop an optimal performance technology base, NASA Dryden Flight Research Center developed and flight tested an adaptive performance seeking control system to optimize the quasi-steady-state performance of the F-15 aircraft. The demonstrated technology is equally applicable to transport aircraft although with less improvement. NASA Dryden, in transitioning this technology to transport aircraft, is specifically exploring the feasibility of applying adaptive optimal control techniques to performance optimization of redundant control effectors. A simulation evaluation of a preliminary control law optimizes wing-aileron camber for minimum net aircraft drag. Two submodes are evaluated: one to minimize fuel and the other to maximize velocity. This paper covers the status of performance optimization of the current fleet of subsonic transports. Available integrated controls technologies are reviewed to define approaches using active controls. A candidate control law for adaptive performance optimization is presented along with examples of algorithm operation.

  1. Evaluation of laminar flow control system concepts for subsonic commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A study was conducted to evaluate alternatives in the design of laminar flow control (LFC) subsonic commercial transport aircraft for operation in the 1980's period. Analyses were conducted to select mission parameters and define optimum aircraft configurational parameters for the selected mission, defined by a passenger payload of 400 and a design range of 12,038 km (6500 n mi). The baseline aircraft developed for this mission was used as a vehicle for the evaluation and development of alternative LFC system concepts. Alternatives were evaluated in the areas of aerodynamics structures, materials, LFC systems, leading-edge region cleaning and integration of auxiliary systems. Based on these evaluations, concept in each area were selected for further development and testing and ultimate incorporation in the final study aircraft. Relative to a similarly-optimized advanced technology turbulent transport, the final LFC configuration is approximately equal in direct operating cost but provides decreases of 8.2% in gross weight and 21.7% in fuel consumption.

  2. Optimized aerodynamic design process for subsonic transport wing fitted with winglets. [wind tunnel model

    NASA Technical Reports Server (NTRS)

    Kuhlman, J. M.

    1979-01-01

    The aerodynamic design of a wind-tunnel model of a wing representative of that of a subsonic jet transport aircraft, fitted with winglets, was performed using two recently developed optimal wing-design computer programs. Both potential flow codes use a vortex lattice representation of the near-field of the aerodynamic surfaces for determination of the required mean camber surfaces for minimum induced drag, and both codes use far-field induced drag minimization procedures to obtain the required spanloads. One code uses a discrete vortex wake model for this far-field drag computation, while the second uses a 2-D advanced panel wake model. Wing camber shapes for the two codes are very similar, but the resulting winglet camber shapes differ widely. Design techniques and considerations for these two wind-tunnel models are detailed, including a description of the necessary modifications of the design geometry to format it for use by a numerically controlled machine for the actual model construction.

  3. Design Methodology for Multi-Element High-Lift Systems on Subsonic Civil Transport Aircraft

    NASA Technical Reports Server (NTRS)

    Pepper, R. S.; vanDam, C. P.

    1996-01-01

    The choice of a high-lift system is crucial in the preliminary design process of a subsonic civil transport aircraft. Its purpose is to increase the allowable aircraft weight or decrease the aircraft's wing area for a given takeoff and landing performance. However, the implementation of a high-lift system into a design must be done carefully, for it can improve the aerodynamic performance of an aircraft but may also drastically increase the aircraft empty weight. If designed properly, a high-lift system can improve the cost effectiveness of an aircraft by increasing the payload weight for a given takeoff and landing performance. This is why the design methodology for a high-lift system should incorporate aerodynamic performance, weight, and cost. The airframe industry has experienced rapid technological growth in recent years which has led to significant advances in high-lift systems. For this reason many existing design methodologies have become obsolete since they are based on outdated low Reynolds number wind-tunnel data and can no longer accurately predict the aerodynamic characteristics or weight of current multi-element wings. Therefore, a new design methodology has been created that reflects current aerodynamic, weight, and cost data and provides enough flexibility to allow incorporation of new data when it becomes available.

  4. Longitudinal aerodynamic characteristics of a subsonic, energy-efficient transport configuration in the National Transonic Facility

    NASA Technical Reports Server (NTRS)

    Jacobs, Peter F.; Gloss, Blair B.

    1989-01-01

    The Reynolds number, aeroelasticity, boundary layer transition, and nonadiabatic wall temperature effects, and data repeatability was determined in the National Transonic Facility (NTF) for a subsonic, energy efficient transport model. The model was tested over a Mach number range of 0.50 to 0.86 and a Reynolds number range of 1.9 million to approximately 23.0 million (based on mean geometric chord). The majority of the data was taken using cryogenic nitrogen (data at 1.9 million Reynolds number was taken in air). Force and moment, wing pressure, and wing thermocouple data are presented. The data indicate that increasing Reynolds number resulted in greater effective camber of the supercritical wing and horizontal tail, resulting in greater lift and pitching moment coefficients at nearly all angles of attack for M = 0.82. As Reynolds number was increased, untrimmed L/D increased, the angle of attack for maximum L/D decreased, drag creep was reduced significantly, and drag divergence Mach number increased slightly. Data repeatability for both modes of operation of the NTF (air and cryogenic nitrogen) was generally very good, and nonadiabatic wall effects were estimated to be small. Transition-free and transition-fixed configurations had significantly different force and moment data at M = 0.82 for low Reynolds number, and very small differences were noted at high Reynolds numbers.

  5. Propulsion system studies for an advanced high subsonic, long range jet commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Propulsion system characteristics for a long range, high subsonic (Mach 0.90 - 0.98), jet commercial transport aircraft are studied to identify the most desirable cycle and engine configuration and to assess the payoff of advanced engine technologies applicable to the time frame of the late 1970s to the mid 1980s. An engine parametric study phase examines major cycle trends on the basis of aircraft economics. This is followed by the preliminary design of two advanced mixed exhaust turbofan engines pointed at two different technology levels (1970 and 1985 commercial certification for engines No. 1 and No. 2, respectively). The economic penalties of environmental constraints - noise and exhaust emissions - are assessed. The highest specific thrust engine (lowest bypass ratio for a given core technology) achievable with a single-stage fan yields the best economics for a Mach 0.95 - 0.98 aircraft and can meet the noise objectives specified, but with significant economic penalties. Advanced technologies which would allow high temperature and cycle pressure ratios to be used effectively are shown to provide significant improvement in mission performance which can partially offset the economic penalties incurred to meet lower noise goals. Advanced technology needs are identified; and, in particular, the initiation of an integrated fan and inlet aero/acoustic program is recommended.

  6. Analysis of noise radiation mechanisms in hot subsonic jet from a validated large eddy simulation solution

    SciTech Connect

    Lorteau, Mathieu Cléro, Franck Vuillot, François

    2015-07-15

    In the framework of jet noise computation, a numerical simulation of a subsonic turbulent hot jet is performed using large-eddy simulation. A geometrical tripping is used in order to trigger the turbulence at the nozzle exit. In a first part, the validity of the simulation is assessed by comparison with experimental measurements. The mean and rms velocity fields show good agreement, so do the azimuthal composition of the near pressure field and the far field spectra. Discrepancies remain close to the nozzle exit which lead to a limited overestimation of the pressure levels in both near and far fields, especially near the 90{sup ∘} angular sector. Two point correlation analyses are then applied to the data obtained from the simulation. These enable to link the downstream acoustic radiation, which is the main direction of radiation, to pressure waves developing in the shear layer and propagating toward the potential core end. The intermittency of the downstream acoustic radiation is evidenced and related to the coherent structures developing in the shear layer.

  7. A method for computation of inviscid three-dimensional flow over blunt bodies having large embedded subsonic regions

    NASA Technical Reports Server (NTRS)

    Weilmuenster, K. J.; Hamilton, H. H., II

    1981-01-01

    A computational technique for computing the three-dimensional inviscid flow over blunt bodies having large regions of embedded subsonic flow is detailed. Results, which were obtained using the CDC Cyber 203 vector processing computer, are presented for several analytic shapes with some comparison to experimental data. Finally, windward surface pressure computations over the first third of the Space Shuttle vehicle are compared with experimental data for angles of attack between 25 and 45 degrees.

  8. Wing pressure distributions from subsonic tests of a high-wing transport model. [in the Langley 14- by 22-Foot Subsonic Wind Tunnel

    NASA Technical Reports Server (NTRS)

    Applin, Zachary T.; Gentry, Garl L., Jr.; Takallu, M. A.

    1995-01-01

    A wind tunnel investigation was conducted on a generic, high-wing transport model in the Langley 14- by 22-Foot Subsonic Tunnel. This report contains pressure data that document effects of various model configurations and free-stream conditions on wing pressure distributions. The untwisted wing incorporated a full-span, leading-edge Krueger flap and a part-span, double-slotted trailing-edge flap system. The trailing-edge flap was tested at four different deflection angles (20 deg, 30 deg, 40 deg, and 60 deg). Four wing configurations were tested: cruise, flaps only, Krueger flap only, and high lift (Krueger flap and flaps deployed). Tests were conducted at free-stream dynamic pressures of 20 psf to 60 psf with corresponding chord Reynolds numbers of 1.22 x 10(exp 6) to 2.11 x 10(exp 6) and Mach numbers of 0.12 to 0.20. The angles of attack presented range from 0 deg to 20 deg and were determined by wing configuration. The angle of sideslip ranged from minus 20 deg to 20 deg. In general, pressure distributions were relatively insensitive to free-stream speed with exceptions primarily at high angles of attack or high flap deflections. Increasing trailing-edge Krueger flap significantly reduced peak suction pressures and steep gradients on the wing at high angles of attack. Installation of the empennage had no effect on wing pressure distributions. Unpowered engine nacelles reduced suction pressures on the wing and the flaps.

  9. Subsonic Euler Flows with Large Vorticity Through an Infinitely Long Axisymmetric Nozzle

    NASA Astrophysics Data System (ADS)

    Du, Lili; Duan, Ben

    2016-09-01

    This paper is a sequel to the earlier work Du and Duan (J Diff Equ 250:813-847, 2011) on well-posedness of steady subsonic Euler flows through infinitely long three-dimensional axisymmetric nozzles. In Du and Duan (J Diff Equ 250:813-847, 2011), the authors showed the existence and uniqueness of the global subsonic Euler flows through an infinitely long axisymmetric nozzle, when the variation of Bernoulli's function in the upstream is sufficiently small and the mass flux of the incoming flow is less than some critical value. The smallness of the variation of Bernoulli's function in the upstream prevents the attendance of the possible singularity in the nozzles, however, at the same time it also leads that the vorticity of the ideal flow is sufficiently small in the whole nozzle and the flows are indeed adjacent to axisymmetric potential flows. The purpose of this paper is to investigate the effects of the vorticity for the smooth subsonic ideal flows in infinitely long axisymmetric nozzles. We modify the formulation of the problem in the previous work Du and Duan (J Diff Equ 250:813-847, 2011) and the existence and uniqueness results on the smooth subsonic ideal polytropic flows in infinitely long axisymmetric nozzles without the restriction on the smallness of the vorticity are shown in this paper.

  10. Study of the application of hydrogen fuel to long-range subsonic transport aircraft. Volume 1: Summary

    NASA Technical Reports Server (NTRS)

    Brewer, G. D.; Morris, R. E.; Lange, R. H.; Moore, J. W.

    1975-01-01

    The feasibility of using liquid hydrogen as fuel in advanced designs of long range, subsonic transport aircraft is assessed. Both passenger and cargo type aircraft are investigated. Comparisons of physical, performance, and economic parameters of the LH2 fueled designs with conventionally fueled aircraft are presented. Design studies are conducted to determine appropriate characteristics for the hydrogen related systems required on board the aircraft. These studies included consideration of material, structural, and thermodynamic requirements of the cryogenic fuel tanks and fuel systems with the structural support and thermal protection systems.

  11. Multivariate Analysis, Retrieval, and Storage System (MARS). Volume 6: MARS System - A Sample Problem (Gross Weight of Subsonic Transports)

    NASA Technical Reports Server (NTRS)

    Hague, D. S.; Woodbury, N. W.

    1975-01-01

    The Mars system is a tool for rapid prediction of aircraft or engine characteristics based on correlation-regression analysis of past designs stored in the data bases. An example of output obtained from the MARS system, which involves derivation of an expression for gross weight of subsonic transport aircraft in terms of nine independent variables is given. The need is illustrated for careful selection of correlation variables and for continual review of the resulting estimation equations. For Vol. 1, see N76-10089.

  12. Transport phenomena in subsonic and supersonic flows in a duct with mass injection

    NASA Astrophysics Data System (ADS)

    Kuo, Shyang-Lin

    1994-01-01

    Film cooling effects have always been crucial for the engine/rocket/ramjet propulsion systems. Knowing the pressure and temperature distribution of the flow is very important for both system and structural analyses to find optimal design. An efficient time dependent, compressible Navier-Stokes solver using higher order accuracy algorithms employing the finite-volume method is developed. The physics inside the flow field with a cooler secondary mass stream injected into the channel is studied. The results showed that for subsonic main flow, the injected mass stream will bend and accelerate in the downstream direction, creating a region of lower temperature near the downstream walls. This lower temperature region also exists even if there is a heat flux added to the flow system. Therefore, film cooling effect exists for the subsonic flow. For supersonic flow, however, the injected mass flow, instead of bending toward the downstream wall in order to have a cooling effect, is bent toward upstream direction and retards the main flow, resulting in a stagnant flow region. The temperature in the entire flow field is found to increase an appreciable amount even though the temperature in the stagnant region is found to be relatively lower than other areas. Therefore, there is no film cooling effect observed for supersonic flow. These phenomena have been verified by the experimental work. For subsonic flow, the acoustical wave is found to travel forwards and backwards in the field system while the pressure gradient is favorable for the whole flow field. For supersonic flow, there is always an adverse pressure gradient region formed near the walls upstream of the mass-injection location. Inside this adverse pressure gradient region, an air bubble is usually found to exist. The flow interactions between the main stream and secondary stream increase the flow vorticity. This vorticity is found to travel in the downstream direction for subsonic flow. However, for supersonic flow

  13. Acoustic Prediction Methodology and Test Validation for an Efficient Low-Noise Hybrid Wing Body Subsonic Transport

    NASA Technical Reports Server (NTRS)

    Kawai, Ronald T. (Compiler)

    2011-01-01

    This investigation was conducted to: (1) Develop a hybrid wing body subsonic transport configuration with noise prediction methods to meet the circa 2007 NASA Subsonic Fixed Wing (SFW) N+2 noise goal of -52 dB cum relative to FAR 36 Stage 3 (-42 dB cum re: Stage 4) while achieving a -25% fuel burned compared to current transports (re :B737/B767); (2) Develop improved noise prediction methods for ANOPP2 for use in predicting FAR 36 noise; (3) Design and fabricate a wind tunnel model for testing in the LaRC 14 x 22 ft low speed wind tunnel to validate noise predictions and determine low speed aero characteristics for an efficient low noise Hybrid Wing Body configuration. A medium wide body cargo freighter was selected to represent a logical need for an initial operational capability in the 2020 time frame. The Efficient Low Noise Hybrid Wing Body (ELNHWB) configuration N2A-EXTE was evolved meeting the circa 2007 NRA N+2 fuel burn and noise goals. The noise estimates were made using improvements in jet noise shielding and noise shielding prediction methods developed by UC Irvine and MIT. From this the Quiet Ultra Integrated Efficient Test Research Aircraft #1 (QUIET-R1) 5.8% wind tunnel model was designed and fabricated.

  14. Research requirements for a real-time flight measurements and data analysis system for subsonic transport high-lift research

    NASA Technical Reports Server (NTRS)

    Whitehead, Julia H.; Harris, Franklin K.; Lytle, Carroll D.

    1993-01-01

    A multiphased research program to obtain detailed flow characteristics on a multielement high-lift flap system is being conducted on the Transport Systems Research Vehicle (B737-100 aircraft) at NASA Langley Research Center. Upcoming flight tests have required the development of a highly capable and flexible flight measurement and data analysis instrumentation system. This instrumentation system will be more comprehensive than any of the systems used on previous high-lift flight experiment at NASA Langley. The system will provide the researcher near-real-time information for decision making needed to modify a flight test in order to further examine unexpected flow conditions. This paper presents the research requirements and instrumentation design concept for an upcoming flight experiment for the subsonic transport high-lift research program. The flight experiment objectives, the measurement requirements, the data acquisition system, and the onboard data analysis and display capabilities are described.

  15. Research requirements for a real-time flight measurements and data analysis system for subsonic transport high-lift research

    NASA Technical Reports Server (NTRS)

    Whitehead, Julia H.; Harris, Franklin K.; Lytle, Carroll D.

    1993-01-01

    A multiphased research program to obtain detailed flow characteristics on a multielement high-lift flap system is being conducted on the Transport Systems Research Vehicle (B737-100 aircraft) at NASA Langley Research Center. Upcoming flight tests have required the development of a highly capable and flexible flight measurement and data analysis instrumentation system. This instrumentation system will be more comprehensive than any of the systems used on previous high-lift flight experiment at NASA Langley. The system will provide the researcher near-real-time information for decision making needed to modify a flight test in order to further examine unexpected flow conditions. This paper presents the research requirements and instrumentation design concept for an upcoming flight experiment for the subsonic transport high-lift research program. The flight experiment objectives, the measurement requirements, the data acquisition system, and the onboard data analysis and display capabilities are described.

  16. Validating a Monotonically-Integrated Large Eddy Simulation Code for Subsonic Jet Acoustics

    NASA Technical Reports Server (NTRS)

    Ingraham, Daniel; Bridges, James

    2017-01-01

    The results of subsonic jet validation cases for the Naval Research Lab's Jet Engine Noise REduction (JENRE) code are reported. Two set points from the Tanna matrix, set point 3 (Ma = 0.5, unheated) and set point 7 (Ma = 0.9, unheated) are attempted on three different meshes. After a brief discussion of the JENRE code and the meshes constructed for this work, the turbulent statistics for the axial velocity are presented and compared to experimental data, with favorable results. Preliminary simulations for set point 23 (Ma = 0.5, Tj=T1 = 1.764) on one of the meshes are also described. Finally, the proposed configuration for the farfield noise prediction with JENRE's Ffowcs-Williams Hawking solver are detailed.

  17. High resolution imaging of a subsonic projectile using automated mirrors with large aperture

    NASA Astrophysics Data System (ADS)

    Tateno, Y.; Ishii, M.; Oku, H.

    2017-02-01

    Visual tracking of high-speed projectiles is required for studying the aerodynamics around the objects. One solution to this problem is a tracking method based on the so-called 1 ms Auto Pan-Tilt (1ms-APT) system that we proposed in previous work, which consists of rotational mirrors and a high-speed image processing system. However, the images obtained with that system did not have high enough resolution to realize detailed measurement of the projectiles because of the size of the mirrors. In this study, we propose a new system consisting of enlarged mirrors for tracking a high-speed projectiles so as to achieve higher-resolution imaging, and we confirmed the effectiveness of the system via an experiment in which a projectile flying at subsonic speed tracked.

  18. Subsonic aerodynamic characteristic of semispan commercial transport model with wing-mounted advanced ducted propeller operating in reverse thrust. [conducted in the Langley 14 by 22 foot subsonic wind tunnel

    NASA Technical Reports Server (NTRS)

    Applin, Zachary T.; Jones, Kenneth M.; Gile, Brenda E.; Quinto, P. Frank

    1994-01-01

    A test was conducted in the Langley 14 by 22 Foot Subsonic Tunnel to determine the effect of the reverse-thrust flow field of a wing-mounted advanced ducted propeller on the aerodynamic characteristics of a semispan subsonic high-lift transport model. The advanced ducted propeller (ADP) model was mounted separately in position alongside the wing so that only the aerodynamic interference of the propeller and nacelle affected the aerodynamic performance of the transport model. Mach numbers ranged from 0.14 to 0.26; corresponding Reynolds numbers ranged from 2.2 to 3.9 x 10(exp 6). The reverse-thrust flow field of the ADP shielded a portion of the wing from the free-stream airflow and reduced both lift and drag. The reduction in lift and drag was a function of ADP rotational speed and free-stream velocity. Test results included ground effects data for the transport model and ADP configuration. The ground plane caused a beneficial increase in drag and an undesirable slight increase in lift. The ADP and transport model performance in ground effect was similar to performance trends observed for out of ground effect. The test results form a comprehensive data set that supports the application of the ADP engine and airplane concept on the next generation of advanced subsonic transports. Before this investigation, the engine application was predicted to have detrimental ground effect characteristics. Ground effect test measurements indicated no critical problems and were the first step in proving the viability of this engine and airplane configuration.

  19. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project. ACT/Control/Guidance System study. Volume 2: Appendices

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The integrated application of active controls (IAAC) technology to an advanced subsonic transport is reported. Supplementary technical data on the following topics are included: (1) 1990's avionics technology assessment; (2) function criticality assessment; (3) flight deck system for total control and functional features list; (4) criticality and reliability assessment of units; (5) crew procedural function task analysis; and (6) recommendations for simulation mechanization.

  20. Analysis for the application of hybrid laminar flow control to a long-range subsonic transport aircraft

    NASA Technical Reports Server (NTRS)

    Arcara, P. C., Jr.; Bartlett, D. W.; Mccullers, L. A.

    1991-01-01

    The FLOPS aircraft conceptual design/analysis code has been used to evaluate the effects of incorporating hybrid laminar flow control (HLFC) in a 300-passenger, 6500 n. mi. range, twin-engine subsonic transport aircraft. The baseline configuration was sized to account for 50 percent chord laminar flow on the wing upper surface as well as both surfaces of the empennage airfoils. Attention is given to the additional benefits of achieving various degrees of laminar flow on the engine nacelles, and the horsepower extraction and initial weight and cost increments entailed by the HLFC system. The sensitivity of the results obtained to fuel-price and off-design range are also noted.

  1. Effect of aileron deflections on the aerodynamic characteristics of a semispan model of a subsonic energy-efficient transport

    NASA Technical Reports Server (NTRS)

    Jacobs, P. F.

    1985-01-01

    An investigation was conducted in the Langley 8 Foot Transonic Pressure Tunnel to determine the effect of aileron deflections on the aerodynamic characteristics of a subsonic energy efficient transport (EET) model. The semispan model had an aspect ratio 10 supercritical wing and was configured with a conventionally located set of ailerons (i.e., a high speed aileron located inboard and a low speed aileron located outboard). Data for the model were taken over a Mach number range from 0.30 to 0.90 and an angle of attack range from approximately -2 deg to 10 deg. The Reynolds number was 2.5 million per foot for Mach number = 0.30 and 4 million per foot for the other Mach numbers. Model force and moment data, aileron effectiveness parameters, aileron hinge moment data, otherwise pressure distributions, and spanwise load data are presented.

  2. Subsonic Investigation of a Leading-Edge Boundary Layer Control Suction System on a High-Speed Civil Transport Configuration

    NASA Technical Reports Server (NTRS)

    Campbell, Bryan A.; Applin, Zachary T.; Kemmerly, Guy T.; Coe, Paul L., Jr.; Owens, D. Bruce; Gile, Brenda E.; Parikh, Pradip G.; Smith, Don

    1999-01-01

    A wind tunnel investigation of a leading edge boundary layer control system was conducted on a High Speed Civil Transport (HSCT) configuration in the Langley 14- by 22-Foot Subsonic Tunnel. Data were obtained over a Mach number range of 0.08 to 0.27, with corresponding chord Reynolds numbers of 1.79 x 10(exp 6) to 5.76 x 10(exp 6). Variations in the amount of suction, as well as the size and location of the suction area, were tested with outboard leading edge flaps deflected 0 and 30 deg and trailing-edge flaps deflected 0 and 20 deg. The longitudinal and lateral aerodynamic data are presented without analysis. A complete tabulated data listing is also presented herein.

  3. In-flight pressure distributions and skin-friction measurements on a subsonic transport high-lift wing section

    NASA Technical Reports Server (NTRS)

    Yip, Long P.; Vijgen, Paul M. H. W.; Hardin, Jay D.; Vandam, C. P.

    1993-01-01

    Flight experiments are being conducted as part of a multiphased subsonic transport high-lift research program for correlation with wind-tunnel and computational results. The NASA Langley Transport Systems Research Vehicle (B737-100 aircraft) is used to obtain in-flight flow characteristics at full-scale Reynolds numbers to contribute to the understanding of 3-D high-lift, multi-element flows including attachment-line transition and relaminarization, confluent boundary-layer development, and flow separation characteristics. Flight test results of pressure distributions and skin friction measurements were obtained for a full-chord wing section including the slat, main-wing, and triple-slotted, Fowler flap elements. Test conditions included a range of flap deflections, chord Reynolds numbers (10 to 21 million), and Mach numbers (0.16 to 0.40). Pressure distributions were obtained at 144 chordwise locations of a wing section (53-percent wing span) using thin pressure belts over the slat, main-wing, and flap elements. Flow characteristics observed in the chordwise pressure distributions included leading-edge regions of high subsonic flows, leading-edge attachment-line locations, slat and main-wing cove-flow separation and reattachment, and trailing-edge flap separation. In addition to the pressure distributions, limited skin-friction measurements were made using Preston-tube probes. Preston-tube measurements on the slat upper surface suggested relaminarization of the turbulent flow introduced by the pressure belt on the slat leading-edge surface when the slat attachment line was laminar. Computational analysis of the in-flight pressure measurements using two-dimensional, viscous multielement methods modified with simple-sweep theory showed reasonable agreement. However, overprediction of the pressures on the flap elements suggests a need for better detailed measurements and improved modeling of confluent boundary layers as well as inclusion of three-dimensional viscous

  4. In-flight pressure distributions and skin-friction measurements on a subsonic transport high-lift wing section

    NASA Technical Reports Server (NTRS)

    Yip, Long P.; Vijgen, Paul M. H. W.; Hardin, Jay D.; Vandam, C. P.

    1993-01-01

    Flight experiments are being conducted as part of a multiphased subsonic transport high-lift research program for correlation with wind-tunnel and computational results. The NASA Langley Transport Systems Research Vehicle (B737-100 aircraft) is used to obtain in-flight flow characteristics at full-scale Reynolds numbers to contribute to the understanding of 3-D high-lift, multi-element flows including attachment-line transition and relaminarization, confluent boundary-layer development, and flow separation characteristics. Flight test results of pressure distributions and skin friction measurements were obtained for a full-chord wing section including the slat, main-wing, and triple-slotted, Fowler flap elements. Test conditions included a range of flap deflections, chord Reynolds numbers (10 to 21 million), and Mach numbers (0.16 to 0.40). Pressure distributions were obtained at 144 chordwise locations of a wing section (53-percent wing span) using thin pressure belts over the slat, main-wing, and flap elements. Flow characteristics observed in the chordwise pressure distributions included leading-edge regions of high subsonic flows, leading-edge attachment-line locations, slat and main-wing cove-flow separation and reattachment, and trailing-edge flap separation. In addition to the pressure distributions, limited skin-friction measurements were made using Preston-tube probes. Preston-tube measurements on the slat upper surface suggested relaminarization of the turbulent flow introduced by the pressure belt on the slat leading-edge surface when the slat attachment line was laminar. Computational analysis of the in-flight pressure measurements using two-dimensional, viscous multielement methods modified with simple-sweep theory showed reasonable agreement. However, overprediction of the pressures on the flap elements suggests a need for better detailed measurements and improved modeling of confluent boundary layers as well as inclusion of three-dimensional viscous

  5. Study of the application of advanced technologies to laminar flow control systems for subsonic transports. Volume 1: Summary

    NASA Technical Reports Server (NTRS)

    Sturgeon, R. F.; Bennett, J. A.; Etchberger, F. R.; Ferrill, R. S.; Meade, L. E.

    1976-01-01

    A study was conducted to evaluate the technical and economic feasibility of applying laminar flow control to the wings and empennage of long-range subsonic transport aircraft compatible with initial operation in 1985. For a design mission range of 10,186 km (5500 n mi), advanced technology laminar-flow-control (LFC) and turbulent-flow (TF) aircraft were developed for both 200 and 400-passenger payloads, and compared on the basis of production costs, direct operating costs, and fuel efficiency. Parametric analyses were conducted to establish the optimum geometry for LFC and TF aircraft, advanced LFC system concepts and arrangements were evaluated, and configuration variations maximizing the effectiveness of LFC were developed. For the final LFC aircraft, analyses were conducted to define maintenance costs and procedures, manufacturing costs and procedures, and operational considerations peculiar to LFC aircraft. Compared to the corresponding advanced technology TF transports, the 200- and 400-passenger LFC aircraft realized reductions in fuel consumption up to 28.2%, reductions in direct operating costs up to 8.4%, and improvements in fuel efficiency, in ssm/lb of fuel, up to 39.4%. Compared to current commercial transports at the design range, the LFC study aircraft demonstrate improvements in fuel efficiency up to 131%. Research and technology requirements requisite to the development of LFC transport aircraft were identified.

  6. Development and validation of cryogenic foam insulation for LH2 subsonic transports

    NASA Technical Reports Server (NTRS)

    Anthony, F. M.; Colt, J. Z.; Helenbrook, R. G.

    1981-01-01

    Fourteen foam insulation specimens were tested. Some were plain foam while others contained flame retardants, chopped fiberglass reinforcement and/or vapor barriers. The thermal performance of the insulation was determined by measuring the rate at which LH2 boiled from an aluminum tank insulated with the test material. The test specimens were approximately 50 mm (2 in.) thick. They were structurally scaled so that the test cycle would duplicate the maximum thermal stresses predicted for the thicker insulation of an aircraft liquid hydrogen fuel tank during a typical subsonic flight. The simulated flight cycle of approximately 10 minutes duration heated the other insulation surface to 316 K (110 F) and cooled it to 226 K (20 F) while the inner insulation surface remained at liquid hydrogen temperature of 20 K (-423 F). Two urethane foam insulations exceeded the initial life goal of 2400 simulated flight cycles and sustained 4400 cycles with only minor damage. The addition of fiberglass reinforcement of flame retardant materials to an insulation degraded thermal performance and/or the life of the foam material. Installation of vapor barriers enhanced the structural integrity of the material but did not improve thermal performance. All of the foams tested were available materials; none were developed specifically for LH2 service.

  7. Design of Supersonic Transport Flap Systems for Thrust Recovery at Subsonic Speeds

    NASA Technical Reports Server (NTRS)

    Mann, Michael J.; Carlson, Harry W.; Domack, Christopher S.

    1999-01-01

    A study of the subsonic aerodynamics of hinged flap systems for supersonic cruise commercial aircraft has been conducted using linear attached-flow theory that has been modified to include an estimate of attainable leading edge thrust and an approximate representation of vortex forces. Comparisons of theoretical predictions with experimental results show that the theory gives a reasonably good and generally conservative estimate of the performance of an efficient flap system and provides a good estimate of the leading and trailing-edge deflection angles necessary for optimum performance. A substantial reduction in the area of the inboard region of the leading edge flap has only a minor effect on the performance and the optimum deflection angles. Changes in the size of the outboard leading-edge flap show that performance is greatest when this flap has a chord equal to approximately 30 percent of the wing chord. A study was also made of the performance of various combinations of individual leading and trailing-edge flaps, and the results show that aerodynamic efficiencies as high as 85 percent of full suction are predicted.

  8. Development and validation of cryogenic foam insulation for LH2 subsonic transports

    NASA Astrophysics Data System (ADS)

    Anthony, F. M.; Colt, J. Z.; Helenbrook, R. G.

    1981-02-01

    Fourteen foam insulation specimens were tested. Some were plain foam while others contained flame retardants, chopped fiberglass reinforcement and/or vapor barriers. The thermal performance of the insulation was determined by measuring the rate at which LH2 boiled from an aluminum tank insulated with the test material. The test specimens were approximately 50 mm (2 in.) thick. They were structurally scaled so that the test cycle would duplicate the maximum thermal stresses predicted for the thicker insulation of an aircraft liquid hydrogen fuel tank during a typical subsonic flight. The simulated flight cycle of approximately 10 minutes duration heated the other insulation surface to 316 K (110 F) and cooled it to 226 K (20 F) while the inner insulation surface remained at liquid hydrogen temperature of 20 K (-423 F). Two urethane foam insulations exceeded the initial life goal of 2400 simulated flight cycles and sustained 4400 cycles with only minor damage. The addition of fiberglass reinforcement of flame retardant materials to an insulation degraded thermal performance and/or the life of the foam material. Installation of vapor barriers enhanced the structural integrity of the material but did not improve thermal performance. All of the foams tested were available materials; none were developed specifically for LH2 service.

  9. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study. Volume 2: Appendices

    NASA Technical Reports Server (NTRS)

    Hanks, G. W.; Shomber, H. A.; Dethman, H. A.; Gratzer, L. B.; Maeshiro, A.; Gangsaas, D.; Blight, J. D.; Buchan, S. M.; Crumb, C. B.; Dorwart, R. J.

    1981-01-01

    The current status of the Active Controls Technology (ACT) for the advanced subsonic transport project is investigated through analysis of the systems technical data. Control systems technologies under examination include computerized reliability analysis, pitch axis fly by wire actuator, flaperon actuation system design trade study, control law synthesis and analysis, flutter mode control and gust load alleviation analysis, and implementation of alternative ACT systems. Extensive analysis of the computer techniques involved in each system is included.

  10. Analysis of a high speed civil transport configuration at subsonic flow conditions using a Navier-Stokes solver

    NASA Technical Reports Server (NTRS)

    Lessard, Victor R.

    1993-01-01

    Computations of three dimensional vortical flows over a generic High Speed Civil Transport (HSCT) configuration with an aspect ratio of 3.04 are performed using a thin-layer Navier-Stokes solver. The HSCT cruise configuration is modeled without leading or trailing edge flap deflections and without engine nacelles. The flow conditions, which correspond to tests done in the NASA Langley 8-Foot Transonic Pressure Tunnel (TPT), are a subsonic Mach number of 0.3 and Reynolds number of 4.4 million for a range-of-attack (-.23 deg to 17.78 deg). The effects of the farfield boundary location with respect to the body are investigated. The boundary layer is assumed turbulent and simulated using an algebraic turbulence model. The key features of the vortices and their interactions are captured. Grid distribution in the vortex regions is critical for predicting the correct induced lift. Computed forces and surface pressures compare reasonably well with the experimental TPT data.

  11. Assessment of the Noise Reduction Potential of Advanced Subsonic Transport Concepts for NASA's Environmentally Responsible Aviation Project

    NASA Technical Reports Server (NTRS)

    Thomas, Russell H.; Burley, Casey L.; Nickol, Craig L.

    2016-01-01

    Aircraft system noise is predicted for a portfolio of NASA advanced concepts with 2025 entry-into-service technology assumptions. The subsonic transport concepts include tube-and-wing configurations with engines mounted under the wing, over the wing nacelle integration, and a double deck fuselage with engines at a mid-fuselage location. Also included are hybrid wing body aircraft with engines upstream of the fuselage trailing edge. Both advanced direct drive engines and geared turbofan engines are modeled. Recent acoustic experimental information was utilized in the prediction for several key technologies. The 301-passenger class hybrid wing body with geared ultra high bypass engines is assessed at 40.3 EPNLdB cumulative below the Stage 4 certification level. Other hybrid wing body and unconventional tube-and-wing configurations reach levels of 33 EPNLdB or more below the certification level. Many factors contribute to the system level result; however, the hybrid wing body in the 301-passenger class, as compared to a tubeand- wing with conventional engine under wing installation, has 11.9 EPNLdB of noise reduction due to replacing reflection with acoustic shielding of engine noise sources. Therefore, the propulsion airframe aeroacoustic interaction effects clearly differentiate the unconventional configurations that approach levels close to or exceed the 42 EPNLdB goal.

  12. An experimental study of the turbulent boundary layer on a transport wing in subsonic and transonic flow

    NASA Technical Reports Server (NTRS)

    Spaid, Frank W.; Roos, Frederick W.; Hicks, Raymond M.

    1990-01-01

    The upper surface boundary layer on a transport wing model was extensively surveyed with miniature yaw probes at a subsonic and a transonic cruise condition. Additional data were obtained at a second transonic test condition, for which a separated region was present at mid-semispan, aft of mid-chord. Significant variation in flow direction with distance from the surface was observed near the trailing edge except at the wing root and tip. The data collected at the transonic cruise condition show boundary layer growth associated with shock wave/boundary layer interaction, followed by recovery of the boundary layer downstream of the shock. Measurements of fluctuating surface pressure and wingtip acceleration were also obtained. The influence of flow field unsteadiness on the boundary layer data is discussed. Comparisons among the data and predictions from a variety of computational methods are presented. The computed predictions are in reasonable agreement with the experimental data in the outboard regions where 3-D effects are moderate and adverse pressure gradients are mild. In the more highly loaded mid-span region near the trailing edge, displacement thickness growth was significantly underpredicted, except when unrealistically severe adverse pressure gradients associated with inviscid calculations were used to perform boundary layer calculations.

  13. Measurements of mean flow and acoustic power for a subsonic jet impinging normal to a large rigid surface

    NASA Technical Reports Server (NTRS)

    Schloth, A. P.

    1976-01-01

    An experimental study was made to measure the mean flow field and acoustic power of a subsonic jet impinging normal to a large rigid surface. A 6.25 cm diameter, circular cool air jet was used at heights of 20, 10, and 5 jet diameters above the surface. The jet exit Mach number was varied from 0.28 to 0.93. Impact and static pressure surveys were made in directions both axial and lateral to the jet axis and also parallel and perpendicular to the surface. Acoustic power was calculated from microphone measurements made during each test run using a diffuse field calibration for the test facility. Results indicate that the flow field for jet impingement is characterized mainly by a strong rise in static pressure in the impingement region near the surface and by boundary layer development in the wall jet region. Acoustic power measurements generally followed a U(8) law for both the free jet and jet impingement although there was some variation especially at high Mach number and for close impingement distances. Overall noise levels increased with decreasing jet-to-surface height. Normalized power spectra correlated well for all cases when the Strouhal number was greater than 0.2; the correlation was poor when the Strouhal number was low.

  14. Evaluation of laminar flow control system concepts for subsonic commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A two-year study conducted to establish a basis for industry decisions on the application of laminar flow control (LFC) to future commercial transports was presented. Areas of investigation included: (1) mission definition and baseline selection; (2) concepts evaluations; and (3) LFC transport configuration selection and component design. The development and evaluation of competing design concepts was conducted in the areas of aerodynamics, structures and materials, and systems. The results of supporting wind tunnel and laboratory testing on a full-scale LFC wing panel, suction surface opening concepts and structural samples were included. A final LFC transport was configured in incorporating the results of concept evaluation studies and potential performance improvements were assessed. Remaining problems together with recommendations for future research are discussed.

  15. Evaluation of laminar flow control system concepts for subsonic commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Results of a 2-year study are reported which were carried out to extend the development of laminar flow control (LFC) technology and evaluate LFC systems concepts. The overall objective of the LFC program is to provide a sound basis for industry decisions on the application of LFC to future commercial transports. The study was organized into major tasks to support the stated objectives through application of LFC systems concepts to a baseline LFC transport initially generated for the study. Based on competitive evaluation of these concepts, a final selection was made for incorporation into the final design of an LFC transport which also included other advanced technology elements appropriate to the 1990 time period.

  16. Integrated Application of Active Controls (IAAC) Technology to an Advanced Subsonic Transport: Project Plan

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The state of the art of active controls technology (ACT) and a recommended ACT development program plan are reviewed. The performance benefits and cost of ownership of an integrated application of ACT to civil transport aircraft is to be assessed along with the risk and laboratory and/or flight experiments designed to reduce the technical risks to a commercially acceptable level.

  17. Assessment of the application of advanced technologies to subsonic CTOL transport aircraft

    NASA Technical Reports Server (NTRS)

    Graef, J. D.; Sallee, G. P.; Verges, J. T.

    1974-01-01

    Design studies of the application of advanced technologies to future transport aircraft were conducted. These studies were reviewed from the perspective of an air carrier. A fundamental study of the elements of airplane operating cost was performed, and the advanced technologies were ranked in order of potential profit impact. Recommendations for future study areas are given.

  18. A Full Navier-Stokes Analysis of Subsonic Diffuser of a Bifurcated 70/30 Supersonic Inlet for High Speed Civil Transport Application

    NASA Technical Reports Server (NTRS)

    Kapoor, Kamlesh; Anderson, Bernhard H.; Shaw, Robert J.

    1994-01-01

    A full Navier-Stokes analysis was performed to evaluate the performance of the subsonic diffuser of a NASA Lewis Research Center 70/30 mixed-compression bifurcated supersonic inlet for high speed civil transport application. The PARC3D code was used in the present study. The computations were also performed when approximately 2.5 percent of the engine mass flow was allowed to bypass through the engine bypass doors. The computational results were compared with the available experimental data which consisted of detailed Mach number and total pressure distribution along the entire length of the subsonic diffuser. The total pressure recovery, flow distortion, and crossflow velocity at the engine face were also calculated. The computed surface ramp and cowl pressure distributions were compared with experiments. Overall, the computational results compared well with experimental data. The present CFD analysis demonstrated that the bypass flow improves the total pressure recovery and lessens flow distortions at the engine face.

  19. Technology developments for laminar boundary layer control on subsonic transport aircraft

    NASA Technical Reports Server (NTRS)

    Wagner, R. D.; Maddalon, D. V.; Fischer, M. C.

    1984-01-01

    The development of laminar flow technology for commercial transport aircraft is discussed and illustrated in a review of studies undertaken in the NASA Aircraft Energy Efficiency (ACEE) program since 1976. The early history of laminar flow control (LFC) techniques and natural laminar flow (NLF) airfoil designs is traced, and the aims of ACEE are outlined. The application of slotted structures, composites, and electron beam perforated metals in supercritical LFC airfoils, wing panels, and leading edge systems is examined; wind tunnel and flight test results are summarized; studies of high altitude ice effects are described; and hybrid (LFC/NLF designs are characterized. Drawings and photographs are provided.

  20. Use of constrained optimization in the conceptual design of a medium-range subsonic transport

    NASA Technical Reports Server (NTRS)

    Sliwa, S. M.

    1980-01-01

    Constrained parameter optimization was used to perform the optimal conceptual design of a medium range transport configuration. The impact of choosing a given performance index was studied, and the required income for a 15 percent return on investment was proposed as a figure of merit. A number of design constants and constraint functions were systematically varied to document the sensitivities of the optimal design to a variety of economic and technological assumptions. A comparison was made for each of the parameter variations between the baseline configuration and the optimally redesigned configuration.

  1. Reynolds Number Effects on a Supersonic Transport at Subsonic High-Lift Conditions (Invited)

    NASA Technical Reports Server (NTRS)

    Owens, L.R.; Wahls, R. A.

    2001-01-01

    A High Speed Civil Transport configuration was tested in the National Transonic Facility at the NASA Langley Research Center as part of NASA's High Speed Research Program. The primary purposes of the tests were to assess Reynolds number scale effects and high Reynolds number aerodynamic characteristics of a realistic, second generation supersonic transport while providing data for the assessment of computational methods. The tests included longitudinal and lateral/directional studies at transonic and low-speed, high-lift conditions across a range of Reynolds numbers from that available in conventional wind tunnels to near flight conditions. Results are presented which focus on Reynolds number and static aeroelastic sensitivities of longitudinal characteristics at Mach 0.30 for a configuration without an empennage. A fundamental change in flow-state occurred between Reynolds numbers of 30 to 40 million, which is characterized by significantly earlier inboard leading-edge separation at the high Reynolds numbers. Force and moment levels change but Reynolds number trends are consistent between the two states.

  2. Investigations of Subsonic Compressible Boundary Layer Flows using Hybrid Large Eddy Simulations

    NASA Astrophysics Data System (ADS)

    Taylor, Sara Jo

    The objective of this thesis is to investigate the spatially developing turbulent compressible boundary layer on a flat plate using the Spalart-Allmaras Detached Eddy Simulation (SA-DES) model [22] and the Nichols-Nelson hybrid Reynolds-Averaged Navier-Stokes/Large Eddy Simulation (RANS/LES) model [13] which have been implemented into the Wind-US 3.0 computational fluid dynamics code [30]; both of the hybrid approaches involve RANS modeling in the near-wall region and LES treatment in the outer region. Generation of unsteady turbulent inflow data is achieved via the prescribed energy spectrum method. The studies illustrated dependence on Reynolds number based on momentum thickness, Reθ, ranging from 3018 to 19430, and dependence on Mach number, M = 0.5 and M = 0.9. The SA-DES model predicted mean flow profiles to a satisfactory degree, and the Nichols-Nelson hybrid RANS/LES model adequately predicted density field fluctuations; the aero-thermal effects captured by the Nichols-Nelson model can be useful for near-field aero optics applications.

  3. The influence of subsonic mission segments on the use of variable-sweep wings for high speed civil transport configurations

    NASA Technical Reports Server (NTRS)

    Martin, Glenn L.; Beissner, Fred L., Jr.; Domack, Christopher S.; Shields, E. William

    1988-01-01

    A Mach-3.0, 250-passenger, 6500-n. mi. range SST configuration's alternative use of fixed-planform or variable-sweep wings is presently evaluated, with a view to effects on aerodynamics, mission performance, and sizing. After preliminary design, the fixed and variable-wing configurations were resized to perform missions incorporating subsonic cruise segments of as much as 4000 n. mi.; the effect of subsonic segment length on design gross weight and block time was then ascertained. Due to the reduced supersonic efficiency of the variable-sweep aircraft, over one-half of the 6500-n. mi. mission would have to be flown subsonically for its sizing to reach a lower ramp weight than that of its fixed-geometry counterpart.

  4. Study of fuel systems for LH2-fueled subsonic transport aircraft, volume 1

    NASA Technical Reports Server (NTRS)

    Brewer, G. D.; Morris, R. E.; Davis, G. W.; Versaw, E. F.; Cunnington, G. R., Jr.; Riple, J. C.; Baerst, C. F.; Garmong, G.

    1978-01-01

    Several engine concepts examined to determine a preferred design which most effectively exploits the characteristics of hydrogen fuel in aircraft tanks received major emphasis. Many candidate designs of tank structure and cryogenic insulation systems were evaluated. Designs of all major elements of the aircraft fuel system including pumps, lines, valves, regulators, and heat exchangers received attention. Selected designs of boost pumps to be mounted in the LH2 tanks, and of a high pressure pump to be mounted on the engine were defined. A final design of LH2-fueled transport aircraft was established which incorporates a preferred design of fuel system. That aircraft was then compared with a conventionally fueled counterpart designed to equivalent technology standards.

  5. Cost/benefit assessment of the application of composite materials to subsonic commercial transport engines

    NASA Technical Reports Server (NTRS)

    Faddoul, J. R.; Signorelli, R. A.

    1976-01-01

    Results from a number of studies concerned with the cost and benefits of applying advanced composite materials to commercial turbofan engines are summarized. For each application area the optimistic and pessimistic benefit projections were averaged to arrive at a projected yearly percentage fuel savings for a commercial fleet of advanced technology transport aircraft. Engine components included in the summary are the fan section which includes fan blades, fan frame/case, and the blade containment ring; the nacelle; and the high pressure turbine blades and vanes. The projected fuel savings resulting from the application of composites are 1.85 percent for the fan section, 1.75 percent for the nacelle, and 2.35 percent for the high pressure turbine.

  6. Wing Configuration Impact on Design Optimums for a Subsonic Passenger Transport

    NASA Technical Reports Server (NTRS)

    Wells, Douglas P.

    2014-01-01

    This study sought to compare four aircraft wing configurations at a conceptual level using a multi-disciplinary optimization (MDO) process. The MDO framework used was created by Georgia Institute of Technology and Virginia Polytechnic Institute and State University. They created a multi-disciplinary design and optimization environment that could capture the unique features of the truss-braced wing (TBW) configuration. The four wing configurations selected for the study were a low wing cantilever installation, a high wing cantilever, a strut-braced wing, and a single jury TBW. The mission that was used for this study was a 160 passenger transport aircraft with a design range of 2,875 nautical miles at the design payload, flown at a cruise Mach number of 0.78. This paper includes discussion and optimization results for multiple design objectives. Five design objectives were chosen to illustrate the impact of selected objective on the optimization result: minimum takeoff gross weight (TOGW), minimum operating empty weight, minimum block fuel weight, maximum start of cruise lift-to-drag ratio, and minimum start of cruise drag coefficient. The results show that the design objective selected will impact the characteristics of the optimized aircraft. Although minimum life cycle cost was not one of the objectives, TOGW is often used as a proxy for life cycle cost. The low wing cantilever had the lowest TOGW followed by the strut-braced wing.

  7. Effects of Nacelle configuration/position on performance of subsonic transport

    NASA Technical Reports Server (NTRS)

    Bangert, L. H.; Krivec, D. K.; Segall, R. N.

    1983-01-01

    An experimental study was conducted to explore possible reductions in installed propulsion system drag due to underwing aft nacelle locations. Both circular (C) and D inlet cross section nacelles were tested. The primary objectives were: to determine the relative installed drag of the C and D nacelle installations; and, to compare the drag of each aft nacelle installation with that of a conventional underwing forward, drag of each aft nacelle installation with that of a conventional underwing forward, pylon mounted (UTW) nacelle installation. The tests were performed in the NASA-Langley Research Center 16-Foot Transonic Wind Tunnel at Mach numbers from 0.70 to 0.85, airplane angles of attack from -2.5 to 4.1 degrees, and Reynolds numbers per foot from 3.4 to 4.0 million. The nacelles were installed on the NASA USB full span transonic transport model with horizontal tail on. The D nacelle installation had the smallest drag of those tested. The UTW nacelle installation had the largest drag, at 6.8 percent larger than the D at Mach number 0.80 and lift coefficient (C sub L) 0.45. Each tested configuration still had some interference drag, however. The effect of the aft nacelles on airplane lift was to increase C sub L at a fixed angle of attack relative to the wing body. There was higher lift on the inboard wing sections because of higher pressures on the wing lower surface. The effects of the UTW installation on lift were opposite to those of the aft nacelles.

  8. High-lift flow-physics flight experiments on a subsonic civil transport aircraft (B737-100)

    NASA Technical Reports Server (NTRS)

    Vandam, Cornelis P.

    1994-01-01

    As part of the subsonic transport high-lift program, flight experiments are being conducted using NASA Langley's B737-100 to measure the flow characteristics of the multi-element high-lift system at full-scale high-Reynolds-number conditions. The instrumentation consists of hot-film anemometers to measure boundary-layer states, an infra-red camera to detect transition from laminar to turbulent flow, Preston tubes to measure wall shear stress, boundary-layer rakes to measure off-surface velocity profiles, and pressure orifices to measure surface pressure distributions. The initial phase of this research project was recently concluded with two flights on July 14. This phase consisted of a total of twenty flights over a period of about ten weeks. In the coming months the data obtained in this initial set of flight experiments will be analyzed and the results will be used to finalize the instrumentation layout for the next set of flight experiments scheduled for Winter and Spring of 1995. The main goal of these upcoming flights will be: (1) to measure more detailed surface pressure distributions across the wing for a range of flight conditions and flap settings; (2) to visualize the surface flows across the multi-element wing at high-lift conditions using fluorescent mini tufts; and (3) to measure in more detail the changes in boundary-layer state on the various flap elements as a result of changes in flight condition and flap deflection. These flight measured results are being correlated with experimental data measured in ground-based facilities as well as with computational data calculated with methods based on the Navier-Stokes equations or a reduced set of these equations. Also these results provide insight into the extent of laminar flow that exists on actual multi-element lifting surfaces at full-scale high-life conditions. Preliminary results indicate that depending on the deflection angle, the slat and flap elements have significant regions of laminar flow over

  9. Three-dimensional aerodynamic analysis of a subsonic transport high-lift configuration and comparisons with wind-tunnel test results

    NASA Technical Reports Server (NTRS)

    Edge, D. Christian; Perkins, John N.

    1995-01-01

    The sizing and efficiency of an aircraft is largely determined by the performance of its high-lift system. Subsonic civil transports most often use deployable multi-element airfoils to achieve the maximum-lift requirements for landing, as well as the high lift-to-drag ratios for take-off. However, these systems produce very complex flow fields which are not fully understood by the scientific community. In order to compete in today's market place, aircraft manufacturers will have to design better high-lift systems. Therefore, a more thorough understanding of the flows associated with these systems is desired. Flight and wind-tunnel experiments have been conducted on NASA Langley's B737-100 research aircraft to obtain detailed full-scale flow measurements on a multi-element high-lift system at various flight conditions. As part of this effort, computational aerodynamic tools are being used to provide preliminary flow-field information for instrumentation development, and to provide additional insight during the data analysis and interpretation process. The purpose of this paper is to demonstrate the ability and usefulness of a three-dimensional low-order potential flow solver, PMARC, by comparing computational results with data obtained from 1/8 scale wind-tunnel tests. Overall, correlation of experimental and computational data reveals that the panel method is able to predict reasonably well the pressures of the aircraft's multi-element wing at several spanwise stations. PMARC's versatility and usefulness is also demonstrated by accurately predicting inviscid three-dimensional flow features for several intricate geometrical regions.

  10. Accelerated development and flight evaluation of active controls concepts for subsonic transport aircraft. Volume 2: AFT C.G. simulation and analysis

    NASA Technical Reports Server (NTRS)

    Urie, D. M.

    1979-01-01

    Relaxed static stability and stability augmentation with active controls were investigated for subsonic transport aircraft. Analytical and simulator evaluations were done using a contemporary wide body transport as a baseline. Criteria for augmentation system performance and unaugmented flying qualities were evaluated. Augmentation control laws were defined based on selected frequency response and time history criteria. Flying qualities evaluations were conducted by pilots using a moving base simulator with a transport cab. Static margin and air turbulence intensity were varied in test with and without augmentation. Suitability of a simple pitch control law was verified at neutral static margin in cruise and landing flight tasks. Neutral stability was found to be marginally acceptable in heavy turbulence in both cruise and landing conditions.

  11. Large capacity oblique all-wing transport aircraft

    NASA Technical Reports Server (NTRS)

    Galloway, Thomas L.; Phillips, James A.; Kennelly, Robert A., Jr.; Waters, Mark H.

    1996-01-01

    Dr. R. T. Jones first developed the theory for oblique wing aircraft in 1952, and in subsequent years numerous analytical and experimental projects conducted at NASA Ames and elsewhere have established that the Jones' oblique wing theory is correct. Until the late 1980's all proposed oblique wing configurations were wing/body aircraft with the wing mounted on a pivot. With the emerging requirement for commercial transports with very large payloads, 450-800 passengers, Jones proposed a supersonic oblique flying wing in 1988. For such an aircraft all payload, fuel, and systems are carried within the wing, and the wing is designed with a variable sweep to maintain a fixed subsonic normal Mach number. Engines and vertical tails are mounted on pivots supported from the primary structure of the wing. The oblique flying wing transport has come to be known as the Oblique All-Wing (OAW) transport. This presentation gives the highlights of the OAW project that was to study the total concept of the OAW as a commercial transport.

  12. Hybrid-Electric and Distributed Propulsion Technologies for Large Commercial Transports: A NASA Perspective

    NASA Technical Reports Server (NTRS)

    Madavan, Nateri K.; Del Rosario, Ruben; Jankovsky, Amy L.

    2015-01-01

    Develop and demonstrate technologies that will revolutionize commercial transport aircraft propulsion and accelerate development of all-electric aircraft architectures. Enable radically different propulsion systems that can meet national environmental and fuel burn reduction goals for subsonic commercial aircraft. Focus on future large regional jets and single-aisle twin (Boeing 737- class) aircraft for greatest impact on fuel burn, noise and emissions. Research horizon is long-term but with periodic spinoff of technologies for introduction in aircraft with more- and all-electric architectures. Research aligned with new NASA Aeronautics strategic R&T thrusts in areas of transition to low-carbon propulsion and ultra-efficient commercial transports.

  13. Development of a Large Field-of-View PIV System for Rotorcraft Testing in the 14- x 22-Foot Subsonic Tunnel

    NASA Technical Reports Server (NTRS)

    Jenkins, Luther N.; Yao, Chung-Sheng; Bartram, Scott M.; Harris, Jerome; Allan, Brian; Wong, Oliver; Mace, W. Derry

    2009-01-01

    A Large Field-of-View Particle Image Velocimetry (LFPIV) system has been developed for rotor wake diagnostics in the 14-by 22-Foot Subsonic Tunnel. The system has been used to measure three components of velocity in a plane as large as 1.524 meters by 0.914 meters in both forward flight and hover tests. Overall, the system performance has exceeded design expectations in terms of accuracy and efficiency. Measurements synchronized with the rotor position during forward flight and hover tests have shown that the system is able to capture the complex interaction of the body and rotor wakes as well as basic details of the blade tip vortex at several wake ages. Measurements obtained with traditional techniques such as multi-hole pressure probes, Laser Doppler Velocimetry (LDV), and 2D Particle Image Velocimetry (PIV) show good agreement with LFPIV measurements.

  14. Effect of Winglets on a First-Generation Jet Transport Wing. 2: Pressure and Spanwise Load Distributions for a Semispan Model at High Subsonic Speeds. [in the Langley 8 ft transonic tunnel

    NASA Technical Reports Server (NTRS)

    Montoya, L. C.; Flechner, S. G.; Jacobs, P. F.

    1977-01-01

    Pressure and spanwise load distributions on a first-generation jet transport semispan model at high subsonic speeds are presented for the basic wing and for configurations with an upper winglet only, upper and lower winglets, and a simple wing-tip extension. Selected data are discussed to show the general trends and effects of the various configurations.

  15. Infrared Images of Boundary Layer Transition on the D8 Transport Configuration in the LaRC 14- by 22-Foot Subsonic Tunnel

    NASA Technical Reports Server (NTRS)

    Mason, Michelle L.; Gatlin, Gregory M.

    2015-01-01

    Grit, trip tape, or trip dots are routinely applied on the leading-edge regions of the fuselage, wings, tails or nacelles of wind tunnel models to trip the flow from laminar to turbulent. The thickness of the model's boundary layer is calculated for nominal conditions in the wind tunnel test to determine the effective size of the trip dots, but the flow over the model may not transition as intended for runs with different flow conditions. Temperature gradients measured with an infrared camera can be used to detect laminar to turbulent boundary layer transition on a wind tunnel model. This non-intrusive technique was used in the NASA Langley 14- by 22-Foot Subsonic Tunnel to visualize the behavior of the flow over a D8 transport configuration model. As the flow through the wind tunnel either increased to or decreased from the run conditions, a sufficient temperature difference existed between the air and the model to visualize the transition location (due to different heat transfer rates through the laminar and the turbulent boundary layers) for several runs in this test. Transition phenomena were visible without active temperature control in the atmospheric wind tunnel, whether the air was cooler than the model or vice-versa. However, when the temperature of the model relative to the air was purposely changed, the ability to detect transition in the infrared images was enhanced. Flow characteristics such as a wing root horseshoe vortex or the presence of fore-body vortical flows also were observed in the infrared images. The images of flow features obtained for this study demonstrate the usefulness of current infrared technology in subsonic wind tunnel tests.

  16. Radiative transport in large arteries

    PubMed Central

    Ruh, Dominic; Subramanian, Sivaraman; Theodor, Michael; Zappe, Hans; Seifert, Andreas

    2013-01-01

    A refined model for the photon energy distribution in a living artery is established by solving the radiative transfer equation in a cylindrical geometry, using the Monte Carlo method. Combining this model with the most recent experimental values for the optical properties of flowing blood and the biomechanics of a blood-filled artery subject to a pulsatile pressure, we find that the optical intensity transmitted through large arteries decreases linearly with increasing arterial distension. This finding provides a solid theoretical foundation for measuring photoplethysmograms. PMID:24466476

  17. Effect of winglets on a first-generation jet transport wing. 5: Stability characteristics of a full-span wing with a generalized fuselage at high subsonic speeds

    NASA Technical Reports Server (NTRS)

    Jacobs, P. F.

    1978-01-01

    The effects of winglets on the static aerodynamic stability characteristics of a KC-135A jet transport model at high subsonic speeds are presented. The investigation was conducted in the Langley 8 foot transonic pressure tunnel using 0.035-scale wing panels mounted on a generalized research fuselage. Data were taken over a Mach number range from 0.50 to 0.95 at angles of attack ranging from -12 deg to 20 deg and sideslip angles of 0 deg, 5 deg, and -5 deg. The model was tested at two Reynolds number ranges to achieve a wide angle of attack range and to determine the effect of Reynolds number on stability. Results indicate that adding the winglets to the basic wing configuration produces small increases in both lateral and longitudinal aerodynamic stability and that the model stability increases slightly with Reynolds number. The winglets do increase the wing bending moments slightly, but the buffet onset characteristics of the model are not affected by the winglets.

  18. Subsonic Investigation of Leading-Edge Flaps Designed for Vortex- and Attached-Flow on a High-Speed Civil Transport Configuration

    NASA Technical Reports Server (NTRS)

    Campbell, Bryan A.; Kemmerly, Guy T.; Kjerstad, Kevin J.; Lessard, Victor R.

    1999-01-01

    A wind tunnel investigation of two separate leading-edge flaps, designed for vortex and attached-flow, respectively, were conducted on a High Speed Civil Transport (HSCT) configuration in the Langley 14- by 22-Foot Subsonic Tunnel. Data were obtained over a Mach number range of 0.12 to 0.27, with corresponding chord Reynolds numbers of 2.50 x 10 (sup 6) to 5.50 x 10 (sup 6). Variations of the leading-edge flap deflection angle were tested with outboard leading-edge flaps deflected 0 deg. and 26.4 deg. Trailing-edge flaps were deflected 0 deg., 10 deg., 12.9 deg., and 20 deg. The longitudinal and lateral aerodynamic data are presented without analysis. A complete tabulated data listing is also presented herein. The data associated with each deflected leading-edge flap indicate L/D improvements over the undeflected configuration. These improvements may be instrumental in providing the necessary lift augmentation required by an actual HSCT during the climb-out and landing phases of the flight envelope. However, further tests will have to be done to assess their full potential.

  19. Aeronautical fuel conservation possibilities for advanced subsonic transports. [application of aeronautical technology for drag and weight reduction

    NASA Technical Reports Server (NTRS)

    Braslow, A. L.; Whitehead, A. H., Jr.

    1973-01-01

    The anticipated growth of air transportation is in danger of being constrained by increased prices and insecure sources of petroleum-based fuel. Fuel-conservation possibilities attainable through the application of advances in aeronautical technology to aircraft design are identified with the intent of stimulating NASA R and T and systems-study activities in the various disciplinary areas. The material includes drag reduction; weight reduction; increased efficiency of main and auxiliary power systems; unconventional air transport of cargo; and operational changes.

  20. Large-scale time-resolved digital particle image velocimetry (TR-DPIV) for measurement of high subsonic hot coaxial jet exhaust of a gas turbine engine

    NASA Astrophysics Data System (ADS)

    Timmerman, B. H.; Skeen, A. J.; Bryanston-Cross, P. J.; Graves, M. J.

    2009-07-01

    The development of a highly configurable triple digital particle image velocimetry (DPIV) system is described, which is capable of acquiring both continuous, statistically independent measurements at up to 14 Hz and time-resolved PIV data at MHz rates. The system was used at QinetiQ's Noise Test Facility (NTF) as part of the EU-funded CoJeN programme to obtain measurements from high subsonic (Mach <= 0.9), hot (~500 °C), large (1/10th) scale coaxial jet flows at a standoff distance of ~1 m. High-resolution time-averaged velocity and turbulence data were obtained for complete coaxial engine exhaust plumes down to 4 m (20 jet diameters) from the nozzle exit in less than 1 h. In addition, the system allowed volumetric data to be obtained, enabling fast assessment of spatial alignment of nozzle configurations. Furthermore, novel six-frame time-series data-capture is demonstrated up to 330 kHz, used to calculate time-space correlations within the exhaust, allowing for study of spatio-temporal developments in the jet, associated with jet-noise production. The highly automated system provides synchronization triggers for simultaneous acquisition from different measurement systems (e.g. LDA) and is shown to be versatile, rugged, reliable and portable, operating remotely in a hostile environment. Data are presented for three operating conditions and two nozzle geometries, providing a database to be used to validate CFD models of coaxial jet flow.

  1. Large Payload Transportation and Test Considerations

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle A.; Pope, James C.

    2011-01-01

    Ironically, the limiting factor to a national heavy lift strategy may not be the rocket technology needed to throw a heavy payload, but rather the terrestrial infrastructure - roads, bridges, airframes, and buildings - necessary to transport, acceptance test, and process large spacecraft. Failure to carefully consider how large spacecraft are designed, and where they are manufactured, tested, or launched, could result in unforeseen cost to modify/develop infrastructure, or incur additional risk due to increased handling or elimination of key verifications. During test and verification planning for the Altair project, a number of transportation and test issues related to the large payload diameter were identified. Although the entire Constellation Program - including Altair - was canceled in the 2011 NASA budget, issues identified by the Altair project serve as important lessons learned for future payloads that may be developed to support national "heavy lift" strategies. A feasibility study performed by the Constellation Ground Operations (CxGO) project found that neither the Altair Ascent nor Descent Stage would fit inside available transportation aircraft. Ground transportation of a payload this large over extended distances is generally not permitted by most states, so overland transportation alone would not have been an option. Limited ground transportation to the nearest waterway may be permitted, but water transportation could take as long as 66 days per production unit, depending on point of origin and acceptance test facility; transportation from the western United States would require transit through the Panama Canal to access the Kennedy Space Center launch site. Large payloads also pose acceptance test and ground processing challenges. Although propulsion, mechanical vibration, and reverberant acoustic test facilities at NASA s Plum Brook Station have been designed to accommodate large spacecraft, special handling and test work-arounds may be necessary

  2. Large Payload Ground Transportation and Test Considerations

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle A.

    2016-01-01

    Many spacecraft concepts under consideration by the National Aeronautics and Space Administration’s (NASA’s) Evolvable Mars Campaign take advantage of a Space Launch System payload shroud that may be 8 to 10 meters in diameter. Large payloads can theoretically save cost by reducing the number of launches needed--but only if it is possible to build, test, and transport a large payload to the launch site in the first place. Analysis performed previously for the Altair project identified several transportation and test issues with an 8.973 meters diameter payload. Although the entire Constellation Program—including Altair—has since been canceled, these issues serve as important lessons learned for spacecraft designers and program managers considering large payloads for future programs. A transportation feasibility study found that, even broken up into an Ascent and Descent Module, the Altair spacecraft would not fit inside available aircraft. Ground transportation of such large payloads over extended distances is not generally permitted, so overland transportation alone would not be an option. Limited ground transportation to the nearest waterway may be possible, but water transportation could take as long as 67 days per production unit, depending on point of origin and acceptance test facility; transportation from the western United States would require transit through the Panama Canal to access the Kennedy Space Center launch site. Large payloads also pose acceptance test and ground processing challenges. Although propulsion, mechanical vibration, and reverberant acoustic test facilities at NASA’s Plum Brook Station have been designed to accommodate large spacecraft, special handling and test work-arounds may be necessary, which could increase cost, schedule, and technical risk. Once at the launch site, there are no facilities currently capable of accommodating the combination of large payload size and hazardous processing such as hypergolic fuels

  3. A study of subsonic transport aircraft configurations using hydrogen (H2) and methane (CH4) as fuel

    NASA Technical Reports Server (NTRS)

    Snow, D. B.; Avery, B. D.; Bodin, L. A.; Baldasare, P.; Washburn, G. F.

    1974-01-01

    The acceptability of alternate fuels for future commercial transport aircraft are discussed. Using both liquid hydrogen and methane, several aircraft configurations are developed and energy consumption, aircraft weights, range and payload are determined and compared to a conventional Boeing 747-100 aircraft. The results show that liquid hydrogen can be used to reduce aircraft energy consumption and that methane offers no advantage over JP or hydrogen fuel.

  4. Large-Eddy/Lattice Boltzmann Simulations of Micro-blowing Strategies for Subsonic and Supersonic Drag Control

    NASA Technical Reports Server (NTRS)

    Menon, Suresh

    2003-01-01

    This report summarizes the progress made in the first 8 to 9 months of this research. The Lattice Boltzmann Equation (LBE) methodology for Large-eddy Simulations (LES) of microblowing has been validated using a jet-in-crossflow test configuration. In this study, the flow intake is also simulated to allow the interaction to occur naturally. The Lattice Boltzmann Equation Large-eddy Simulations (LBELES) approach is capable of capturing not only the flow features associated with the flow, such as hairpin vortices and recirculation behind the jet, but also is able to show better agreement with experiments when compared to previous RANS predictions. The LBELES is shown to be computationally very efficient and therefore, a viable method for simulating the injection process. Two strategies have been developed to simulate multi-hole injection process as in the experiment. In order to allow natural interaction between the injected fluid and the primary stream, the flow intakes for all the holes have to be simulated. The LBE method is computationally efficient but is still 3D in nature and therefore, there may be some computational penalty. In order to study a large number or holes, a new 1D subgrid model has been developed that will simulate a reduced form of the Navier-Stokes equation in these holes.

  5. Large Payload Ground Transportation and Test Considerations

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle A.

    2016-01-01

    During test and verification planning for the Altair lunar lander project, a National Aeronautics and Space Administration (NASA) study team identified several ground transportation and test issues related to the large payload diameter. Although the entire Constellation Program-including Altair-has since been canceled, issues identified by the Altair project serve as important lessons learned for payloads greater than 7 m diameter being considered for NASA's new Space Launch System (SLS). A transportation feasibility study found that Altair's 8.97 m diameter Descent Module would not fit inside available aircraft. Although the Ascent Module cabin was only 2.35 m diameter, the long reaction control system booms extended nearly to the Descent Module diameter, making it equally unsuitable for air transportation without removing the booms and invalidating assembly workmanship screens or acceptance testing that had already been performed. Ground transportation of very large payloads over extended distances is not generally permitted by most states, so overland transportation alone would not be an option. Limited ground transportation to the nearest waterway may be possible, but water transportation could take as long as 66 days per production unit, depending on point of origin and acceptance test facility; transportation from the western United States would require transit through the Panama Canal to access the Kennedy Space Center launch site. Large payloads also pose acceptance test and ground processing challenges. Although propulsion, mechanical vibration, and reverberant acoustic test facilities at NASA's Plum Brook Station have been designed to accommodate large spacecraft, special handling and test work-arounds may be necessary, which could increase cost, schedule, and technical risk. Once at the launch site, there are no facilities currently capable of accommodating the combination of large payload size and hazardous processing such as hypergolic fuels

  6. Observation of subsonic and supersonic radiation fronts on OMEGA utilizing radiation transport through Sc-doped aerogels

    NASA Astrophysics Data System (ADS)

    Johns, H. M.; Kline, J.; Lanier, N.; Perry, T.; Fontes, C.; Fryer, C.; Brown, C.; Morton, J.; Hager, J.

    2016-10-01

    The propagation of a heat front in an astrophysical or inertial confinement fusion plasma involves both the equation of state and the opacity of the plasma, and is therefore an important and challenging radiation transport problem. Past experiments have used absorption spectroscopy in chlorinated foams to measure the heat front. (D. Hoarty et al. PRL 82, 3070, 1999). Recent development of Ti-doped cylindrical aerogel foam targets (J. Hager et al. submitted to RSI) results in a more suitable platform for higher temperatures on NIF than Cl dopant. Ti K-shell absorption spectra can be modeled with PrismSPECT to obtain spatially resolved temperature profiles between 100-180eV. Sc dopant has been selected to characterize the heat front between 60-100eV. Improved understanding of non-planckian x-ray drives generated by hohlraums will advance characterization of the radiation transport. Prior work demonstrates PrismSPECT with OPLIB is more physically complete for Sc (H. Johns et al. submitted to RSI). We will present the first application of spectroscopic analysis of the Sc-doped aerogels utilizing this method. This work performed under the auspices of the U.S. Department of Energy by LANL under contract DE-AC52-06NA25396.

  7. Advanced Subsonic Combustion Rig Developed

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Advanced Subsonic Combustion Rig (ASCR), a unique, state-of-the-art facility for conducting combustion research, is located at the NASA Lewis Research Center in Cleveland, Ohio. The ASCR, which was nearing completion at the close of 1995, will be capable of simulating the very high pressure and high temperature conditions that are expected to exist in future, advanced subsonic gas turbine (jet) engines. Future environmental regulations will require much cleaner burning (more environmentally friendly) aircraft engines. The ASCR is critical to the development of these cleaner engines. It will allow NASA and U.S. aircraft engine industry researchers to identify and test promising clean-burning gas turbine engine combustion concepts under the pressure and temperature conditions that are expected for those future engines. Combustion processes will be investigated for a variety of next-generation aircraft engine sizes, including engines for large, long-range aircraft (with typical trip lengths of about 3000 mi) and for regional aircraft (with typical trip lengths of about 400 mi). The ASCR design was conceived and initiated in 1993, and fabrication and construction of the rig, including the buildup of an advanced control room, took place throughout 1994 and 1995. In early 1996, the ASCR will be operational for obtaining research data. The ASCR is an intricate part of the NASA Advanced Subsonic Technology Propulsion Program, which is aimed at developing technologies critical to the next generation of gas turbine engines. This effort is in collaboration with the U.S. aircraft gas turbine engine industry. A goal of the Advanced Subsonic Technology Propulsion Program is to develop combustion concepts and technologies that will result in gas turbine engines that produce 50 percent less nitrous oxide (NO_x) pollutants than current engines do. This facility is unique in its capability to simulate advanced subsonic engine pressure, temperature, and air flow rate conditions

  8. Integrative application of active controls (IAAC) technology to an advanced subsonic transport project. Initial act configuration design study

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The performance and economic benefits of a constrained application of Active Controls Technology (ACT) are identified, and the approach to airplane design is established for subsequent steps leading to the development of a less constrained final ACT configuration. The active controls configurations are measured against a conventional baseline configuration, a state-of-the-art transport, to determine whether the performance and economic changes resulting from ACT merit proceeding with the project. The technology established by the conventional baseline configuration was held constant except for the addition of ACT. The wing, with the same planform, was moved forward on the initial ACT configuration to move the loading range aft relative to the wing mean aerodynamic chord. Wing trailing-edge surfaces and surface controls also were reconfigured for load alleviation and structural stabilization.

  9. NASA N+3 Subsonic Fixed Wing Silent Efficient Low-Emissions Commercial Transport (SELECT) Vehicle Study. Revision A

    NASA Technical Reports Server (NTRS)

    Bruner, Sam; Baber, Scott; Harris,Chris; Caldwell, Nicholas; Keding, Peter; Rahrig, Kyle; Pho, Luck; Wlezian, Richard

    2010-01-01

    A conceptual commercial passenger transport study was performed to define a single vehicle for entry into service in the 2030 to 2035 timeframe, meeting customer demands as well as NASA goals for improved fuel economy, NOx emissions, noise, and operability into smaller airports. A study of future market and operational scenarios was used to guide the design of an advanced tube-and-wing configuration that utilized advanced material and structural concepts, an advanced three-shaft high-bypass turbofan engine, natural laminar flow technology, and a suite of other advanced technologies. This configuration was found to meet the goals for NOx emissions, noise, and field length. A 64 percent improvement in fuel economy compared to a current state-of-the-art airliner was achieved, which fell slightly short of the desired 70 percent goal. Technology maturation plans for the technologies used in the design were developed to help guide future research and development activities.

  10. Subsonic Aircraft Safety Icing Study

    NASA Technical Reports Server (NTRS)

    Jones, Sharon Monica; Reveley, Mary S.; Evans, Joni K.; Barrientos, Francesca A.

    2008-01-01

    NASA's Integrated Resilient Aircraft Control (IRAC) Project is one of four projects within the agency s Aviation Safety Program (AvSafe) in the Aeronautics Research Mission Directorate (ARMD). The IRAC Project, which was redesigned in the first half of 2007, conducts research to advance the state of the art in aircraft control design tools and techniques. A "Key Decision Point" was established for fiscal year 2007 with the following expected outcomes: document the most currently available statistical/prognostic data associated with icing for subsonic transport, summarize reports by subject matter experts in icing research on current knowledge of icing effects on control parameters and establish future requirements for icing research for subsonic transports including the appropriate alignment. This study contains: (1) statistical analyses of accident and incident data conducted by NASA researchers for this "Key Decision Point", (2) an examination of icing in other recent statistically based studies, (3) a summary of aviation safety priority lists that have been developed by various subject-matter experts, including the significance of aircraft icing research in these lists and (4) suggested future requirements for NASA icing research. The review of several studies by subject-matter experts was summarized into four high-priority icing research areas. Based on the Integrated Resilient Aircraft Control (IRAC) Project goals and objectives, the IRAC project was encouraged to conduct work in all of the high-priority icing research areas that were identified, with the exception of the developing of methods to sense and document actual icing conditions.

  11. Integrated application of active controls (IAAC) technology to an advanced subsonic transport project. Initial ACT configuration design study

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The initial ACT configuration design task of the integrated application of active controls (IAAC) technology project within the Energy Efficient Transport Program is summarized. A constrained application of active controls technology (ACT) resulted in significant improvements over a conventional baseline configuration previously established. The configuration uses the same levels of technology, takeoff gross weight, payload, and design requirements/objectives as the baseline, except for flying qualities, flutter, and ACT. The baseline wing is moved forward 1.68 m. The configuration incorporates pitch-augmented stability (which enabled an approximately 10% aft shift in cruise center of gravity and a 45% reduction in horizontal tail size), lateral/directional-augmented stability, an angle of attack limiter, wing load alleviation, and flutter mode control. This resulted in a 930 kg reduction in airplane operating empty weight and a 3.6% improvement in cruise efficiency, yielding a 13% range increase. Adjusted to the 3590 km baseline mission range, this amounts to 6% block fuel reduction and a 15.7% higher incremental return on investment, using 1978 dollars and fuel cost.

  12. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Wing planform study and final configuration selection

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The Wing Planform Study and Final Configuration Selection Task of the Integrated Application of Active Controls (IAAC) Technology Project within the Energy Efficient Transport Program is documented. Application of Active Controls Technology (ACT) in combination with increased wing span resulted in significant improvements over the Conventional Baseline Configuration (Baseline) and the Initial ACT Configuration previously established. The configurations use the same levels of technology, takeoff gross weight, and payload as the Baseline. The Final ACT Configuration (Model 768-107) incorporates pitch-augmented stability (which enabled an approximately 10% aft shift in cruise center of gravity and a 44% reduction in horizontal tail size), lateral/directional-augmented stability, an angle-of-attack limiter, and wing-load alleviation. Flutter-mode control was not beneficial for this configuration. This resulted in an 890 kg (1960 lb) reduction in airplane takeoff gross weight and a 9.8% improvement in cruise lift/drag. At the Baseline mission range (3589 km 1938 nmi), this amounts to 10% block-fuel reduction. Results of this task strongly indicate that the IAAC Project should proceed with the Final ACT evaluation, and begin the required control system development and test.

  13. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Final ACT configuration evaluation

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The Final ACT Configuration Evaluation Task of the Integrated Application of Active Controls (IAAC) technology project within the energy efficient transport program is summarized. The Final ACT Configuration, through application of Active Controls Technology (ACT) in combination with increased wing span, exhibits significant performance improvements over the conventional baseline configuration. At the design range for these configurations, 3590 km, the block fuel used is 10% less for the Final ACT Configuration, with significant reductions in fuel usage at all operational ranges. Results of this improved fuel usage and additional system and airframe costs and the complexity required to achieve it were analyzed to determine its economic effects. For a 926 km mission, the incremental return on investment is nearly 25% at 1980 fuel prices. For longer range missions or increased fuel prices, the return is greater. The technical risks encountered in the Final ACT Configuration design and the research and development effort required to reduce these risks to levels acceptable for commercial airplane design are identified.

  14. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Wing planform study and final configuration selection

    NASA Technical Reports Server (NTRS)

    1981-01-01

    This report summarizes the Wing Planform Study Task and Final Configuration Selection of the Integrated Application of Active Controls (IAAC) Technology Project within the Energy Efficient Transport Program. Application of Active Controls Technology (ACT) in combination with increased wing span resulted in significant improvements over the Conventional Baseline Configuration (Baseline) and the Initial ACT Configuration previously established. The configurations use the same levels of technology (except for ACT), takeoff gross weight, and payload as the Baseline. The Final ACT Configuration (Model 768-107) incorporates pitch-augmented stability (which enabled an approximately 10% aft shift in cruise center of gravity and a 45% reduction in horizontal tail sizes), lateral/directional-augmented stability, an angle-of-attack limiter, and wing-load alleviation. Flutter-mode control was not beneficial for this configuration. This resulted in an 890 kg (1960 lb) reduction in airplane takeoff gross weight and a 9.8% improvement in cruise lift/drag. At the Baseline mission range (3590 km) (1938 nmi), this amounts to 10% block fuel reduction. Good takeoff performance at high-altitude airports on a hot day was also achieved. Results of this task strongly indicate that the IAAC Project should proceed with the Final ACT evaluation and begin the required control system development and testing.

  15. Integrated application of active controls (IAAC) technology to an advanced subsonic transport project. Conventional baseline configuration study

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Characteristics of the U.S. domestic fleet were evaluated to determine the mission characteristics that would have the most impact on U. S. transport fuel use in the future. This resulted in selection of a 197-passenger (plus cargo), about 3710-km (2000 nmi) mission. The existing data base was reviewed and additional analysis was conducted as necessary to complete the technical descriptions. The resulting baseline configuration utilizes a double-lobe, but nearly circular, body with seven-abreast seating. External characteristics feature an 8.71 aspect ratio, 31.5-degree sweep wing, a T-tail empennage, and a dual CF6-6D2, wing-mounted engine arrangement. It provides for 22 LD-2 or 11 LD-3 containers plus bulk cargo in the lower lobe. Passenger/cargo loading, servicing provisions, taxi/takeoff speeds, and field length characteristics are all compatible with accepted airline operations and regulatory provisions. The baseline configuration construction uses conventional aluminum structure except for advanced aluminum alloys and a limited amount of graphite epoxy secondary structure. Modern systems are used, including advanced guidance, navigation, and controls which emphasize application of digital electronics and advanced displays.

  16. Viscous-flow analysis of a subsonic transport aircraft high-lift system and correlation with flight data

    NASA Technical Reports Server (NTRS)

    Potter, R. C.; Vandam, C. P.

    1995-01-01

    High-lift system aerodynamics has been gaining attention in recent years. In an effort to improve aircraft performance, comprehensive studies of multi-element airfoil systems are being undertaken in wind-tunnel and flight experiments. Recent developments in Computational Fluid Dynamics (CFD) offer a relatively inexpensive alternative for studying complex viscous flows by numerically solving the Navier-Stokes (N-S) equations. Current limitations in computer resources restrict practical high-lift N-S computations to two dimensions, but CFD predictions can yield tremendous insight into flow structure, interactions between airfoil elements, and effects of changes in airfoil geometry or free-stream conditions. These codes are very accurate when compared to strictly 2D data provided by wind-tunnel testing, as will be shown here. Yet, additional challenges must be faced in the analysis of a production aircraft wing section, such as that of the NASA Langley Transport Systems Research Vehicle (TSRV). A primary issue is the sweep theory used to correlate 2D predictions with 3D flight results, accounting for sweep, taper, and finite wing effects. Other computational issues addressed here include the effects of surface roughness of the geometry, cove shape modeling, grid topology, and transition specification. The sensitivity of the flow to changing free-stream conditions is investigated. In addition, the effects of Gurney flaps on the aerodynamic characteristics of the airfoil system are predicted.

  17. Large wood recruitment and transport during large floods: A review

    NASA Astrophysics Data System (ADS)

    Comiti, F.; Lucía, A.; Rickenmann, D.

    2016-09-01

    Large wood (LW) elements transported during large floods are long known to have the capacity to induce dangerous obstructions along the channel network, mostly at bridges and at hydraulic structures such as weirs. However, our current knowledge of wood transport dynamics during high-magnitude flood events is still very scarce, mostly because these are (locally) rare and thus unlikely to be directly monitored. Therefore, post-event surveys are invaluable ways to get insights (although indirectly) on LW recruitment processes, transport distance, and factors inducing LW deposition - all aspects that are crucial for the proper management of river basins related to flood hazard mitigation. This paper presents a review of the (quite limited) literature available on LW transport during large floods, drawing extensively on the authors' own experience in mountain and piedmont rivers, published and unpublished. The overall picture emerging from these studies points to a high, catchment-specific variability in all the different processes affecting LW dynamics during floods. Specifically, in the LW recruitment phase, the relative floodplain (bank erosion) vs. hillslope (landslide and debris flows) contribution in mountain rivers varies substantially, as it relates to the extent of channel widening (which depends on many variables itself) but also to the hillslope-channel connectivity of LW mobilized on the slopes. As to the LW transport phase within the channel network, it appears to be widely characterized by supply-limited conditions; whereby LW transport rates (and thus volumes) are ultimately constrained by the amount of LW that is made available to the flow. Indeed, LW deposition during floods was mostly (in terms of volume) observed at artificial structures (bridges) in all the documented events. This implies that the estimation of LW recruitment and the assessment of clogging probabilities for each structure (for a flood event of given magnitude) are the most important

  18. Design of Large Momentum Acceptance Transport Systems

    SciTech Connect

    D.R. Douglas

    2005-05-01

    The use of energy recovery to enable high power linac operation often gives rise to an attendant challenge--the transport of high power beams subtending large phase space volumes. In particular applications--such as FEL driver accelerators--this manifests itself as a requirement for beam transport systems with large momentum acceptance. We will discuss the design, implementation, and operation of such systems. Though at times counterintuitive in behavior (perturbative descriptions may, for example, be misleading), large acceptance systems have been successfully utilized for generations as spectrometers and accelerator recirculators [1]. Such systems are in fact often readily designed using appropriate geometric descriptions of beam behavior; insight provided using such a perspective may in addition reveal inherent symmetries that simplify construction and improve operability. Our discussion will focus on two examples: the Bates-clone recirculator used in the Jefferson Lab 10 kW IR U pgrade FEL (which has an observed acceptance of 10% or more) and a compaction-managed mirror-bend achromat concept with an acceptance ranging from 50 to 150 MeV.

  19. Cost Analysis for Large Civil Transport Rotorcraft

    NASA Technical Reports Server (NTRS)

    Coy, John J.

    2006-01-01

    This paper presents cost analysis of purchase price and DOC+I (direct operating cost plus interest) that supports NASA s study of three advanced rotorcraft concepts that could enter commercial transport service within 10 to 15 years. The components of DOC+I are maintenance, flight crew, fuel, depreciation, insurance, and finance. The cost analysis aims at VTOL (vertical takeoff and landing) and CTOL (conventional takeoff and landing) aircraft suitable for regional transport service. The resulting spreadsheet-implemented cost models are semi-empirical and based on Department of Transportation and Army data from actual operations of such aircraft. This paper describes a rationale for selecting cost tech factors without which VTOL is more costly than CTOL by a factor of 10 for maintenance cost and a factor of two for purchase price. The three VTOL designs selected for cost comparisons meet the mission requirement to fly 1,200 nautical miles at 350 knots and 30,000 ft carrying 120 passengers. The lowest cost VTOL design is a large civil tilt rotor (LCTR) aircraft. With cost tech factors applied, the LCTR is reasonably competitive with the Boeing 737-700 when operated in economy regional service following the business model of the selected baseline operation, that of Southwest Airlines.

  20. Cost Analysis for Large Civil Transport Rotorcraft

    NASA Technical Reports Server (NTRS)

    Coy, John J.

    2006-01-01

    This paper presents cost analysis of purchase price and DOC+I (direct operating cost plus interest) that supports NASA s study of three advanced rotorcraft concepts that could enter commercial transport service within 10 to 15 years. The components of DOC+I are maintenance, flight crew, fuel, depreciation, insurance, and finance. The cost analysis aims at VTOL (vertical takeoff and landing) and CTOL (conventional takeoff and landing) aircraft suitable for regional transport service. The resulting spreadsheet-implemented cost models are semi-empirical and based on Department of Transportation and Army data from actual operations of such aircraft. This paper describes a rationale for selecting cost tech factors without which VTOL is more costly than CTOL by a factor of 10 for maintenance cost and a factor of two for purchase price. The three VTOL designs selected for cost comparisons meet the mission requirement to fly 1,200 nautical miles at 350 knots and 30,000 ft carrying 120 passengers. The lowest cost VTOL design is a large civil tilt rotor (LCTR) aircraft. With cost tech factors applied, the LCTR is reasonably competitive with the Boeing 737-700 when operated in economy regional service following the business model of the selected baseline operation, that of Southwest Airlines.

  1. Wind tunnel investigation of a large-scale upper surface blown-flap transport model having two engines

    NASA Technical Reports Server (NTRS)

    Aoyagi, K.; Falarski, M. D.; Koenig, D. G.

    1973-01-01

    An investigation has been conducted to determine the aerodynamic characteristics of a large-scale subsonic jet transport model with an upper surface blowing flap system that would augment lift. The model had a 25 deg swept wing of aspect ratio 7.89 and two turbofan engines with the engine centerline located at 0.256 of the wing semispan. The lift of the flap system was augmented by turbofan exhaust impingement on the Coanda surface. Results were obtained for several flap deflections and engine nozzle configurations at jet momentum coefficients from 0 to 4.0. Three-component longitudinal data are presented with two engines operating. Limited longitudinal and lateral data are presented with an engine out. In addition, limited exhaust and flap pressure data are presented.

  2. Derivation and evaluation of an approximate analysis for three-dimensional viscous subsonic flow with large secondary velocities. [finite difference method

    NASA Technical Reports Server (NTRS)

    Anderson, O. L.; Briley, W. R.; Mcdonald, H.

    1978-01-01

    An approximate analysis is presented for calculating three-dimensional, low Mach number, laminar viscous flows in curved passages with large secondary flows and corner boundary layers. The analysis is based on the decomposition of the overall velocity field into inviscid and viscous components with the overall velocity being determined from superposition. An incompressible vorticity transport equation is used to estimate inviscid secondary flow velocities to be used as corrections to the potential flow velocity field. A parabolized streamwise momentum equation coupled to an adiabatic energy equation and global continuity equation is used to obtain an approximate viscous correction to the pressure and longitudinal velocity fields. A collateral flow assumption is invoked to estimate the viscous correction to the transverse velocity fields. The approximate analysis is solved numerically using an implicit ADI solution for the viscous pressure and velocity fields. An iterative ADI procedure is used to solve for the inviscid secondary vorticity and velocity fields. This method was applied to computing the flow within a turbine vane passage with inlet flow conditions of M = 0.1 and M = 0.25, Re = 1000 and adiabatic walls, and for a constant radius curved rectangular duct with R/D = 12 and 14 and with inlet flow conditions of M = 0.1, Re = 1000, and adiabatic walls.

  3. Advanced Subsonic Combustion Rig

    NASA Technical Reports Server (NTRS)

    Lee, Chi-Ming

    1998-01-01

    Researchers from the NASA Lewis Research Center have obtained the first combustion/emissions data under extreme future engine operating conditions. In Lewis' new world-class 60-atm combustor research facility--the Advanced Subsonic Combustion Rig (ASCR)--a flametube was used to conduct combustion experiments in environments as extreme as 900 psia and 3400 F. The greatest challenge for combustion researchers is the uncertainty of the effects of pressure on the formation of nitrogen oxides (NOx). Consequently, U.S. engine manufacturers are using these data to guide their future combustor designs. The flametube's metal housing has an inside diameter of 12 in. and a length of 10.5 in. The flametube can be used with a variety of different flow paths. Each flow path is lined with a high-temperature, castable refractory material (alumina) to minimize heat loss. Upstream of the flametube is the injector section, which has an inside diameter of 13 in. and a length of 0.5-in. It was designed to provide for quick changeovers. This flametube is being used to provide all U.S. engine manufacturers early assessments of advanced combustion concepts at full power conditions prior to engine production. To date, seven concepts from engine manufacturers have been evaluated and improved. This collaborated development can potentially give U.S. engine manufacturers the competitive advantage of being first in the market with advanced low-emission technologies.

  4. Advanced Subsonic Combustion Rig

    NASA Technical Reports Server (NTRS)

    Lee, Chi-Ming

    1998-01-01

    Researchers from the NASA Lewis Research Center have obtained the first combustion/emissions data under extreme future engine operating conditions. In Lewis' new world-class 60-atm combustor research facility--the Advanced Subsonic Combustion Rig (ASCR)--a flametube was used to conduct combustion experiments in environments as extreme as 900 psia and 3400 F. The greatest challenge for combustion researchers is the uncertainty of the effects of pressure on the formation of nitrogen oxides (NOx). Consequently, U.S. engine manufacturers are using these data to guide their future combustor designs. The flametube's metal housing has an inside diameter of 12 in. and a length of 10.5 in. The flametube can be used with a variety of different flow paths. Each flow path is lined with a high-temperature, castable refractory material (alumina) to minimize heat loss. Upstream of the flametube is the injector section, which has an inside diameter of 13 in. and a length of 0.5-in. It was designed to provide for quick changeovers. This flametube is being used to provide all U.S. engine manufacturers early assessments of advanced combustion concepts at full power conditions prior to engine production. To date, seven concepts from engine manufacturers have been evaluated and improved. This collaborated development can potentially give U.S. engine manufacturers the competitive advantage of being first in the market with advanced low-emission technologies.

  5. Large-Scale Stratospheric Transport Processes

    NASA Technical Reports Server (NTRS)

    Plumb, R. Alan

    2001-01-01

    The paper discusses the following: 1. The Brewer-Dobson circulation: tropical upwelling. 2. Mixing into polar vortices. 3. The latitudinal structure of "age" in the stratosphere. 4. The subtropical "tracer edges". 5. Transport in the lower troposphere. 6. Tracer modeling during SOLVE. 7. 3D modeling of "mean age". 8. Models and measurements II.

  6. Large-scale Atmospheric Transport Processes

    NASA Technical Reports Server (NTRS)

    Plumb, R. Alan

    2004-01-01

    Continuing earlier work, we continued an investigation of the seasonal behavior of the edges of the stratospheric surf zone. These edges form a barrier between the rapidly mixed surf zone and the relatively isolated tropics. In collaboration with Dr Lynn Sparling at GSFC, we used a statistical analysis of HALOE and CLAES trace gas data from UARS to identify and locate these edges during each UARS observing period. We found that the edges on both sides of the equator are present all year (a fact that is important for conceptual models of stratospheric transport), though that on the summer side of the equator is much less sharp than the winter edge. The edges migrate seasonally into the summer hemisphere. Their location also shows influence of the QBO, together with the SAO at higher altitudes. Comparisons with effective diffusivities, and the edge locations, suggest that the edge is sustained by surf zone entrainment during winter, but by the residual circulation during summer.

  7. Large-scale Stratospheric Transport Processes

    NASA Technical Reports Server (NTRS)

    Plumb, R. Alan

    2003-01-01

    The PI has undertaken a theoretical analysis of the existence and nature of compact tracer-tracer relationships of the kind observed in the stratosphere, augmented with three-dimensional model simulations of stratospheric tracers (the latter being an extension of modeling work the group did during the SOLVE experiment). This work achieves a rigorous theoretical basis for the existence and shape of these relationships, as well as a quantitative theory of their width and evolution, in terms of the joint tracer-tracer PDF distribution. A paper on this work is almost complete and will soon be submitted to Rev. Geophys. We have analyzed lower stratospheric water in simulations with an isentropic-coordinate version of the MATCH transport model which we recently helped to develop. The three-dimensional structure of lower stratospheric water, in particular, attracted our attention: dry air is, below about 400K potential temperature, localized in the regions of the west Pacific and equatorial South America. We have been analyzing air trajectories to determine how air passes through the tropopause cold trap. This work is now being completed, and a paper will be submitted to Geophys. Res. Lett. before the end of summer. We are continuing to perform experiments with the 'MATCH' CTM, in both sigma- and entropy-coordinate forms. We earlier found (in collaboration with Dr Natalie Mahowald, and as part of an NSF-funded project) that switching to isentropic coordinates made a substantial improvement to the simulation of the age of stratospheric air. We are now running experiments with near-tropopause sources in both versions of the model, to see if and to what extent the simulation of stratosphere-troposphere transport is dependent on the model coordinate. Personnel Research is supervised by the PI, Prof. Alan Plumb. Mr William Heres conducts the tracer modeling work and performs other modeling tasks. Two graduate students, Ms Irene Lee and Mr Michael Ring, have been participating

  8. Transport of large solids in sewer pipes.

    PubMed

    Walski, Thomas; Edwards, Bryce; Helfer, Emil; Whitman, Brian E

    2009-07-01

    This paper presents a method for determining the conditions under which large solids (i.e., solids with a vertical dimension greater than the depth of water) are able to move in a pipe. Depending on the value of a dimensionless number [s(d/y) - 1], where s = specific gravity of the solids, d = water depth, and y = height of solids, motion will occur if a sufficient velocity (also reported as a Froude number or modified "solids" Froude number) is exceeded. Flume experiments were used to determine the coefficients to be used in the design. The velocity required to reach fluid movement was approximately 0.6 to 1.0 m/s (2 to 3 ft/s), which is consistent, although slightly higher than values generally used in conventional sewer design practice. However, it was demonstrated that increasing the pipe slope to achieve a higher velocity does not ensure that the solid will move.

  9. Robust, Optimal Subsonic Airfoil Shapes

    NASA Technical Reports Server (NTRS)

    Rai, Man Mohan

    2014-01-01

    A method has been developed to create an airfoil robust enough to operate satisfactorily in different environments. This method determines a robust, optimal, subsonic airfoil shape, beginning with an arbitrary initial airfoil shape, and imposes the necessary constraints on the design. Also, this method is flexible and extendible to a larger class of requirements and changes in constraints imposed.

  10. Factors controlling large-wood transport in a mountain river

    NASA Astrophysics Data System (ADS)

    Ruiz-Villanueva, Virginia; Wyżga, Bartłomiej; Zawiejska, Joanna; Hajdukiewicz, Maciej; Stoffel, Markus

    2016-11-01

    As with bedload transport, wood transport in rivers is governed by several factors such as flow regime, geomorphic configuration of the channel and floodplain, or wood size and shape. Because large-wood tends to be transported during floods, safety and logistical constraints make field measurements difficult. As a result, direct observation and measurements of the conditions of wood transport are scarce. This lack of direct observations and the complexity of the processes involved in wood transport may result in an incomplete understanding of wood transport processes. Numerical modelling provides an alternative approach to addressing some of the unknowns in the dynamics of large-wood in rivers. The aim of this study is to improve the understanding of controls governing wood transport in mountain rivers, combining numerical modelling and direct field observations. By defining different scenarios, we illustrate relationships between the rate of wood transport and discharge, wood size, and river morphology. We test these relationships for a wide, multithread reach and a narrower, partially channelized single-thread reach of the Czarny Dunajec River in the Polish Carpathians. Results indicate that a wide range of quantitative information about wood transport can be obtained from a combination of numerical modelling and field observations and from document contrasting patterns of wood transport in single- and multithread river reaches. On the one hand, log diameter seems to have a greater importance for wood transport in the multithread channel because of shallower flow, lower flow velocity, and lower stream power. Hydrodynamic conditions in the single-thread channel allow transport of large-wood pieces, whereas in the multithread reach, logs with diameters similar to water depth are not being moved. On the other hand, log length also exerts strong control on wood transport, more so in the single-thread than in the multithread reach. In any case, wood transport strongly

  11. The requirements for a new full scale subsonic wind tunnel

    NASA Technical Reports Server (NTRS)

    Kelly, M. W.; Mckinney, M. O.; Luidens, R. W.

    1972-01-01

    Justification and requirements are presented for a large subsonic wind tunnel capable of testing full scale aircraft, rotor systems, and advanced V/STOL propulsion systems. The design considerations and constraints for such a facility are reviewed, and the trades between facility test capability and costs are discussed.

  12. INTERIOR VIEW WITH LARGE, COMPLETED VALVEMOLD BEING TRANSPORTED BY THE ...

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

    INTERIOR VIEW WITH LARGE, COMPLETED VALVE-MOLD BEING TRANSPORTED BY THE "BOX FLOOR" OVERHEAD RAIL CRANE TO THE POURING AREA. (THE BOX FLOOR AREA IS WHERE THE COMPANY PREPARES MOLDS TOO LARGE TO BE MADE ON MOLDING MACHINES OR POURED ON THE CONVEYOR) - Stockham Pipe & Fittings Company, Ductile Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  13. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project-longitudinal handling qualities study of a relaxed-stability airplane

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The results of a piloted simulation of longitudinal handling qualities of an airplane with relaxed static stability are described. This task was performed under the Integrated Application of Active Controls (IAAC) Technology Project within the NASA Energy Efficient Transport Program. A representative medium range transport airplane, the Boeing Model 757, was simulated. Evaluations were made of the unaugmented airplane and of the airplane with an Essential Pitch Augmented Stability (PAS) System and with a Primary PAS System at various center of gravity (cg) conditions. Level 2 pilot ratings were attained with cg locations aft to about 57% mean aerodynamic chord (MAC) or 6% aft of the neutral point for unaugmented landing approach. For Mach = 0.80, unaugmented cruise Level 2 ratings were attained to 47% MAC or 5% forward of the maneuver point. The augmented airplane model provided handling qualities close to or within the Level 1 boundary at all cg locations for both Essential and Primary PAS. Analyses of the test conditions when compared with existing handling qualities criteria based on classical unaugmented airplane characteristics agreed well with the pilot ratings. The unaugmented results are comparable to those reported by both the Douglas Aircraft Company and Lockheed California Company from simulation investigations of transport configurations with roughly similar dimensional and mass characteristics.

  14. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: current and advanced act control system definition study

    SciTech Connect

    Not Available

    1982-04-01

    The Current and Advanced Technology ACT control system definition tasks of the Integrated Application of Active Controls (IAAC) Technology project within the Energy Efficient Transport Program are summarized. The systems mechanize six active control functions: (1) pitch augmented stability (2) angle of attack limiting (3) lateral/directional augmented stability (4) gust load alleviation (5) maneuver load control and (6) flutter mode control. The redundant digital control systems meet all function requirements with required reliability and declining weight and cost as advanced technology is introduced.

  15. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The Current and Advanced Technology ACT control system definition tasks of the Integrated Application of Active Controls (IAAC) Technology project within the Energy Efficient Transport Program are summarized. The systems mechanize six active control functions: (1) pitch augmented stability; (2) angle of attack limiting; (3) lateral/directional augmented stability; (4) gust load alleviation; (5) maneuver load control; and (6) flutter mode control. The redundant digital control systems meet all function requirements with required reliability and declining weight and cost as advanced technology is introduced.

  16. Transportation of Large Wind Components: A Permitting and Regulatory Review

    SciTech Connect

    Levine, Aaron; Cook, Jeff

    2016-09-01

    This report summarizes permitting and regulatory issues associated with transporting wind turbine blades, towers, and nacelles as well as large transformers (wind components). These wind components are commonly categorized as oversized and overweight (OSOW) and require specific permit approvals from state and local jurisdictions. The report was developed based on a Quadrennial Energy Review (QER) recommendation on logistical requirements for the transportation of 'oversized or high-consequence energy materials, equipment, and components.'

  17. On the Formation of Shock Waves in Subsonic Flows With Local Supersonic Velocities

    NASA Technical Reports Server (NTRS)

    Frankl, F. I.

    1950-01-01

    In the flow about a body with large subsonic velocity if the velocity of the approaching flow is sufficiently large, regions of local supersonic velocities are formed about the body. It is known from experiment that these regions downstream of the flow are always bounded by shock waves; a continuous transition of the supersonic velocity to the subsonic under the conditions indicated has never been observed. A similar phenomenon occurs in pipes. If at two cross sections of the pipe the velocity is subsonic and between these sections regions of local supersonic velocity are formed without completely occupying a single cross section, these regions are always bounded by shock waves.

  18. Robust, optimal subsonic airfoil shapes

    NASA Technical Reports Server (NTRS)

    Rai, Man Mohan (Inventor)

    2008-01-01

    Method system, and product from application of the method, for design of a subsonic airfoil shape, beginning with an arbitrary initial airfoil shape and incorporating one or more constraints on the airfoil geometric parameters and flow characteristics. The resulting design is robust against variations in airfoil dimensions and local airfoil shape introduced in the airfoil manufacturing process. A perturbation procedure provides a class of airfoil shapes, beginning with an initial airfoil shape.

  19. Subsonic Wind Tunnel Testing Handbook

    DTIC Science & Technology

    1991-05-01

    1532 For the wing, 17 - 4PH stainless steel screws... f= 120000 psi S.F. - 120000 = 78.4 1532 Screw head pullout in wing tip missile attachment... shear...Handbook, Subsonic, Wind Tunnel Testing 16. PRICE CODE 17 . SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20. LIMITATION OF...XI- 16 XI-4 Raw Balance Data ........ .......................... XI- 17 A-1 Dynamic Pressure Determination

  20. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project. ACT/Control/Guidance System study, volume 1

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The active control technology (ACT) control/guidance system task of the integrated application of active controls (IAAC) technology project within the NASA energy efficient transport program was documented. The air traffic environment of navigation and air traffic control systems and procedures were extrapolated. An approach to listing flight functions which will be performed by systems and crew of an ACT configured airplane of the 1990s, and a determination of function criticalities to safety of flight, are the basis of candidate integrated ACT/Control/Guidance System architecture. The system mechanizes five active control functions: pitch augmented stability, angle of attack limiting, lateral/directional augmented stability, gust load alleviation, and maneuver load control. The scope and requirements of a program for simulating the integrated ACT avionics and flight deck system, with pilot in the loop, are defined, system and crew interface elements are simulated, and mechanization is recommended. Relationships between system design and crew roles and procedures are evaluated.

  1. Classical convective energy transport in large gradient regions

    SciTech Connect

    Hinton, F.L.

    1996-12-31

    Large gradients in density and temperature occur near the edge in H-mode plasmas and in the core of tokamak plasmas with negative central shear. Transport in these regions may be comparable to neoclassical. Standard neoclassical theory does not apply when the gradient lengths are comparable to an ion orbit excursion, or banana width. A basic question for neoclassical transport in large gradient regions is: do ion-ion collisions drive particle transport? Near the plasma edge in H-mode, where ion orbit loss requires that the ion energy transport be convective, neoclassical particle transport due to ion-ion collisions may play an important role. In negative central shear plasmas, where transport is inferred to be near neoclassical, it is important to have accurate predictions for the neoclassical rate of energy and particle transport. A simple 2-D slab model has been used, with a momentum-conserving collision operator, to show that ion-ion collisions do drive particle transport. When the gradients are large, the {open_quotes}field particle{close_quotes} contribution to the particle flux is non-local, and does not cancel the {open_quotes}test particle{close_quotes} contribution, which is local. Solutions of the kinetic equation are found which show that the steepness of the density profile, for increasing particle flux, is limited by orbit averaging. The gradient length is limited by the thermal gyroradius, and the convective energy flux is independent of ion temperature. This will allow an ion thermal runaway to occur, if there are no other ion energy loss mechanisms.

  2. Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Final ACT configuration evaluation. Final Report, October 1980-April 1981

    SciTech Connect

    Not Available

    1982-02-01

    The Final ACT Configuration Evaluation Task of the Integrated Application of Active Controls (IAAC) technology project within the energy efficient transport program is summarized. The Final ACT Configuration, through application of Active Controls Technology (ACT) in combination with increased wing span, exhibits significant performance improvements over the conventional baseline configuration. At the design range for these configurations, 3590 km, the block fuel used is 10% less for the Final ACT Configuration, with significant reductions in fuel usage at all operational ranges. Results of this improved fuel usage and additional system and airframe costs and the complexity required to achieve it were analyzed to determine its economic effects. For a 926 km mission, the incremental return on investment is nearly 25% at 1980 fuel prices. For longer range missions or increased fuel prices, the return is greater. The technical risks encountered in the Final ACT Configuration design and the research and development effort required to reduce these risks to levels acceptable for commercial airplane design are identified.

  3. LARGE-SCALE CO2 TRANSPORTATION AND DEEP OCEAN SEQUESTRATION

    SciTech Connect

    Hamid Sarv

    1999-03-01

    Technical and economical feasibility of large-scale CO{sub 2} transportation and ocean sequestration at depths of 3000 meters or grater was investigated. Two options were examined for transporting and disposing the captured CO{sub 2}. In one case, CO{sub 2} was pumped from a land-based collection center through long pipelines laid on the ocean floor. Another case considered oceanic tanker transport of liquid carbon dioxide to an offshore floating structure for vertical injection to the ocean floor. In the latter case, a novel concept based on subsurface towing of a 3000-meter pipe, and attaching it to the offshore structure was considered. Budgetary cost estimates indicate that for distances greater than 400 km, tanker transportation and offshore injection through a 3000-meter vertical pipe provides the best method for delivering liquid CO{sub 2} to deep ocean floor depressions. For shorter distances, CO{sub 2} delivery by parallel-laid, subsea pipelines is more cost-effective. Estimated costs for 500-km transport and storage at a depth of 3000 meters by subsea pipelines and tankers were 1.5 and 1.4 dollars per ton of stored CO{sub 2}, respectively. At these prices, economics of ocean disposal are highly favorable. Future work should focus on addressing technical issues that are critical to the deployment of a large-scale CO{sub 2} transportation and disposal system. Pipe corrosion, structural design of the transport pipe, and dispersion characteristics of sinking CO{sub 2} effluent plumes have been identified as areas that require further attention. Our planned activities in the next Phase include laboratory-scale corrosion testing, structural analysis of the pipeline, analytical and experimental simulations of CO{sub 2} discharge and dispersion, and the conceptual economic and engineering evaluation of large-scale implementation.

  4. THE LARGE ASPECT RATIO LIMIT OF NEOCLASSICAL TRANSPORT THEORY

    SciTech Connect

    WONG,SK; CHAN,VS

    2002-11-01

    OAK B202 THE LARGE ASPECT RATIO LIMIT OF NEOCLASSICAL TRANSPORT THEORY. This article presents a comprehensive description of neoclassical transport theory in the banana regime for large aspect ratio flux surfaces of arbitrary shapes. The method of matched asymptotic expansions is used to obtain analytical solutions for plasma distribution functions and to compute transport coefficients. The method provides justification for retaining only the part of the Fokker-Planck operator that involves the second derivative with respect to the cosine of the pitch angle for the trapped and barely circulating particles. It leads to a simple equation for the freely circulating particles with boundary conditions that embody a discontinuity separating particles moving in opposite directions. Corrections to the transport coefficients are obtained by generalizing an existing boundary layer analysis. The system of moment and field equations is consistently taken in the cylinder limit, which facilitates discussion of the treatment of dynamical constraints. it is shown that the nonlocal nature of Ohm's law in neoclassical theory renders the mathematical problem of plasma transport with changing flux surfaces nonstandard.

  5. Empirical relations between large wood transport and catchment characteristics

    NASA Astrophysics Data System (ADS)

    Steeb, Nicolas; Rickenmann, Dieter; Rickli, Christian; Badoux, Alexandre

    2017-04-01

    The transport of vast amounts of large wood (LW) in water courses can considerably aggravate hazardous situations during flood events, and often strongly affects resulting flood damage. Large wood recruitment and transport are controlled by various factors which are difficult to assess and the prediction of transported LW volumes is difficult. Such information are, however, important for engineers and river managers to adequately dimension retention structures or to identify critical stream cross-sections. In this context, empirical formulas have been developed to estimate the volume of transported LW during a flood event (Rickenmann, 1997; Steeb et al., 2017). The data base of existing empirical wood load equations is, however, limited. The objective of the present study is to test and refine existing empirical equations, and to derive new relationships to reveal trends in wood loading. Data have been collected for flood events with LW occurrence in Swiss catchments of various sizes. This extended data set allows us to derive statistically more significant results. LW volumes were found to be related to catchment and transport characteristics, such as catchment size, forested area, forested stream length, water discharge, sediment load, or Melton ratio. Both the potential wood load and the fraction that is effectively mobilized during a flood event (effective wood load) are estimated. The difference of potential and effective wood load allows us to derive typical reduction coefficients that can be used to refine spatially explicit GIS models for potential LW recruitment.

  6. a Numerical Model for Subsonic Acoustic Choking.

    NASA Astrophysics Data System (ADS)

    Walkington, Noel John

    In aircraft turbofan inlets, fan generated noise is observed experimentally to be significantly attenuated at high subsonic inlet Mach numbers. This phenomenon cannot be predicted by linear acoustic theory. In order to study the physical process by which this may occur, a numerical algorithm has been developed to solve a related nonlinear problem in one dimensional gas dynamics. The nonlinear solution admits the possibility of wave steepening and shock waves. Approximate solutions are obtained using several finite difference schemes. The boundary conditions required to model an acoustic source and an anechoic termination are developed. The numerical solutions agree closely with those obtained using the method of matched asymptotic expansions. Solutions involving shock waves exhibit a large reduction in the ratio of transmitted to incident power. This offers an explanation for acoustic choking. The results indicate that more power is dissipated as the Mach number, sound amplitude and frequency are increased. These observations are in agreement with those observed experimentally.

  7. Advanced core technology - Key to subsonic propulsion benefits

    NASA Technical Reports Server (NTRS)

    Glassman, Arthur J.; Snyder, Christopher A.; Knip, Gerald, Jr.

    1989-01-01

    A study was conducted to identify the potential performance benefits and key technology drivers associated with advanced cores for subsonic high bypass turbofan engines. Investigated first were the individual sensitivities of varying compressor efficiency, pressure ratio and bleed (turbine cooling); combustor pressure recovery; and turbine efficiency and inlet temperature on thermal efficiency and core specific power output. Then, engine cycle and mission performance benefits were determined for systems incorporating all potentially achievable technology advancements. The individual thermodynamic sensitivities are shown over a range of turbine temperatures (at cruise) from 2900 to 3500 R and for both constant (current technology) and optimum (maximum thermal efficiency) overall pressure ratios. It is seen that no single parameter alone will provide a large increase in core thermal efficiency, which is the thermodynamic parameter of most concern for transport propulsion. However, when all potentially achievable advancements are considered, there occurs a synergism that produces significant cycle and mission performance benefits. The nature of these benefits are presented along with the technology challenges.

  8. Advanced core technology: Key to subsonic propulsion benefits

    NASA Technical Reports Server (NTRS)

    Glassman, Arthur J.; Snyder, Christopher A.; Knip, Gerald, Jr.

    1989-01-01

    A study was conducted to identify the potential performance benefits and key technology drivers associated with advanced cores for subsonic high bypass turbofan engines. Investigated first were the individual sensitivities of varying compressor efficiency, pressure ratio and bleed (turbine cooling); combustor pressure recovery; and turbine efficiency and inlet temperature on thermal efficiency and core specific power output. Then, engine cycle and mission performance benefits were determined for systems incorporating all potentially achievable technology advancements. The individual thermodynamic sensitivities are shown over a range of turbine temperatures (at cruise) from 2900 to 3500 R and for both constant (current technology) and optimum (maximum thermal efficiency) overall pressure ratios. It is seen that no single parameter alone will provide a large increase in core thermal efficiency, which is the thermodynamic parameter of most concern for transport propulsion. However, when all potentially achievable advancements are considered, there occurs a synergism that produces significant cycle and mission performance benefits. The nature of these benefits are presented along with the technology challenges.

  9. Sediment transport in the presence of large reef bottom roughness

    USGS Publications Warehouse

    Pomeroy, Andrew; Lowe, Ryan J.; Ghisalberti, Marco; Storlazzi, Curt; Symonds, Graham; Roelvink, Dano

    2017-01-01

    The presence of large bottom roughness, such as that formed by benthic organisms on coral reef flats, has important implications for the size, concentration, and transport of suspended sediment in coastal environments. A 3 week field study was conducted in approximately 1.5 m water depth on the reef flat at Ningaloo Reef, Western Australia, to quantify the cross-reef hydrodynamics and suspended sediment dynamics over the large bottom roughness (∼20–40 cm) at the site. A logarithmic mean current profile consistently developed above the height of the roughness; however, the flow was substantially reduced below the height of the roughness (canopy region). Shear velocities inferred from the logarithmic profile and Reynolds stresses measured at the top of the roughness, which are traditionally used in predictive sediment transport formulations, were similar but much larger than that required to suspend the relatively coarse sediment present at the bed. Importantly, these stresses did not represent the stresses imparted on the sediment measured in suspension and are therefore not relevant to the description of suspended sediment transport in systems with large bottom roughness. Estimates of the bed shear stresses that accounted for the reduced near-bed flow in the presence of large roughness vastly improved the relationship between the predicted and observed grain sizes that were in suspension. Thus, the impact of roughness, not only on the overlying flow but also on bed stresses, must be accounted for to accurately estimate suspended sediment transport in regions with large bottom roughness, a common feature of many shallow coastal ecosystems.

  10. Wind tunnel investigation of a large-scale 25 deg swept-wing jet transport model with an external blowing triple-slotted flap

    NASA Technical Reports Server (NTRS)

    Aoyagi, K.; Falarski, M. D.; Koenig, D. G.

    1973-01-01

    An investigation has been conducted to determine the aerodynamic characteristics of a large-scale subsonic jet transport model with an externally blown triple-slotted flap. The lift of the model was augmented by the turbofan engine exhaust impingement on the flap surface. The model had a 25 deg swept wing of aspect ratio 7.28 and four turbofan engines. The model was tested with two flap extents. One extended from 0.11 to 1.00 of the wing semispan, and the other extended from 0.11 to 0.75 of the wing semispan with a single-slotted aileron from 0.75 to 1.00 of the wing semispan. The results were obtained for several flap deflections with and without the horizontal tail at gross thrust coefficients from 0 to 4.0. Longitudinal and lateral data are presented with three and four engines operating.

  11. Cosmic radiation exposure in subsonic air transport

    NASA Technical Reports Server (NTRS)

    Wallace, R. W.; Sondhaus, C. A.

    1978-01-01

    Data derived from 1973 statistics on 2.99 million intercity flights carrying 468 million seats were included in the calculations, yielding a total of 581 billion seat-kilometer. The average flight was 1,084 km in length, was flown at an altitude of 9.47 km, and lasted 1.41 h. The average dose rate was 0.20 mrem/h, resulting in an average passenger dose of 2.82 mrem/year and an average crewmember dose of 160 mrem/year. The average radiation dose to the total U.S. population was 0.47 mrem/person/year. These results are in good agreement with data from several experiments performed by us and others in aircraft at various altitudes and latitudes. The significance of these doses to the population is discussed.

  12. Joint of back-support in large aperture transport mirrors

    NASA Astrophysics Data System (ADS)

    Chen, X. J.; Wu, W. K.; Liu, C. C.; Wang, B. X.; Zhu, M. Z.; Que, X. H.

    2016-10-01

    The wavefront distortion can directly influence on the optics quality of laser beam in ICF laser facility. The gravity is one of the major factors that cause the wavefront distortion. The back-support technology of the large aperture transport mirror has been developed to lessen the wavefront distortion caused by gravity. In the back-support technology, a joint structure between the mirror and the metal back-support has been developed. The requirement of joint is that the firm connection is realized with less wavefront distortion introduced. The adhesive structure and expanding mandrel structure have been analyzed and tested. The back-support of transport mirror in target area use the expanding mandrel for the reasons of the technics and fundamental frequency. The choice of material, the calculation force of clamp, the test of tensile, and the wavefront distortion analysis of transport mirror have been developed. The results show that the expanding mandrel can be used for the back-support of the large aperture transport mirror.

  13. Impact of large scale flows on turbulent transport

    NASA Astrophysics Data System (ADS)

    Sarazin, Y.; Grandgirard, V.; Dif-Pradalier, G.; Fleurence, E.; Garbet, X.; Ghendrih, Ph; Bertrand, P.; Besse, N.; Crouseilles, N.; Sonnendrücker, E.; Latu, G.; Violard, E.

    2006-12-01

    The impact of large scale flows on turbulent transport in magnetized plasmas is explored by means of various kinetic models. Zonal flows are found to lead to a non-linear upshift of turbulent transport in a 3D kinetic model for interchange turbulence. Such a transition is absent from fluid simulations, performed with the same numerical tool, which also predict a much larger transport. The discrepancy cannot be explained by zonal flows only, despite they being overdamped in fluids. Indeed, some difference remains, although reduced, when they are artificially suppressed. Zonal flows are also reported to trigger transport barriers in a 4D drift-kinetic model for slab ion temperature gradient (ITG) turbulence. The density gradient acts as a source drive for zonal flows, while their curvature back stabilizes the turbulence. Finally, 5D simulations of toroidal ITG modes with the global and full-f GYSELA code require the equilibrium density function to depend on the motion invariants only. If not, the generated strong mean flows can completely quench turbulent transport.

  14. Oligomeric tubulin in large transporting complex is transported via kinesin in squid giant axons.

    PubMed

    Terada, S; Kinjo, M; Hirokawa, N

    2000-09-29

    Slow axonal transport depends on an active mechanism that conveys cytosolic proteins. To investigate its molecular mechanism, we now constructed an in vitro experimental system for observation of tubulin transport, using squid giant axons. After injecting fluorescence-labeled tubulin into the axons, we monitored the movement of fluorescence by confocal laser scanning microscopy and fluorescence correlation spectroscopy. Here, from the pharmacological experiments and the functional blocking of kinesin motor protein by anti-kinesin antibody, we show that the directional movement of fluorescent profile was dependent on kinesin motor function. The fluorescent correlation function and estimated translational diffusion time revealed that tubulin molecule was transported in a unique form of large transporting complex distinct from those of stable polymers or other cytosolic protein.

  15. Technology Assessment for Large Vertical-Lift Transport Tiltrotors

    NASA Technical Reports Server (NTRS)

    Germanowski, Peter J.; Stille, Brandon L.; Strauss, Michael P.

    2010-01-01

    The technical community has identified rotor efficiency as a critical enabling technology for large vertical-lift transport (LVLT) rotorcraft. The size and performance of LVLT aircraft will be far beyond current aircraft capabilities, enabling a transformational change in cargo transport effectiveness. Two candidate approaches for achieving high efficiency were considered for LVLT applications: a variable-diameter tiltrotor (VDTR) and a variable-speed tiltrotor (VSTR); the former utilizes variable-rotor geometry and the latter utilizes variable-rotor speed. Conceptual aircraft designs were synthesized for the VDTR and VSTR and compared to a conventional tiltrotor (CTR). The aircraft were optimized to a common objective function and bounded by a set of physical- and requirements-driven constraints. The resulting aircraft were compared for weight, size, performance, handling qualities, and other attributes. These comparisons established a measure of the relative merits of the variable-diameter and -speed rotor systems as enabling technologies for LVLT capability.

  16. Radiation Transport in Random Media With Large Fluctuations

    NASA Astrophysics Data System (ADS)

    Olson, Aaron; Prinja, Anil; Franke, Brian

    2017-09-01

    Neutral particle transport in media exhibiting large and complex material property spatial variation is modeled by representing cross sections as lognormal random functions of space and generated through a nonlinear memory-less transformation of a Gaussian process with covariance uniquely determined by the covariance of the cross section. A Karhunen-Loève decomposition of the Gaussian process is implemented to effciently generate realizations of the random cross sections and Woodcock Monte Carlo used to transport particles on each realization and generate benchmark solutions for the mean and variance of the particle flux as well as probability densities of the particle reflectance and transmittance. A computationally effcient stochastic collocation method is implemented to directly compute the statistical moments such as the mean and variance, while a polynomial chaos expansion in conjunction with stochastic collocation provides a convenient surrogate model that also produces probability densities of output quantities of interest. Extensive numerical testing demonstrates that use of stochastic reduced-order modeling provides an accurate and cost-effective alternative to random sampling for particle transport in random media.

  17. Coupled Eulerian-Lagrangian transport of large debris by tsunamis

    NASA Astrophysics Data System (ADS)

    Conde, Daniel A. S.; Ferreira, Rui M. L.; Sousa Oliveira, Carlos

    2016-04-01

    Tsunamis are notorious for the large disruption they can cause on coastal environments, not only due to the imparted momentum of the incoming wave but also due to its capacity to transport large quantities of solid debris, either from natural or human-made sources, over great distances. A 2DH numerical model under development at CERIS-IST (Ferreira et al., 2009; Conde, 2013) - STAV2D - capable of simulating solid transport in both Eulerian and Lagrangian paradigms will be used to assess the relevance of Lagrangian-Eulerian coupling when modelling the transport of solid debris by tsunamis. The model has been previously validated and applied to tsunami scenarios (Conde, 2013), being well-suited for overland tsunami propagation and capable of handling morphodynamic changes in estuaries and seashores. The discretization scheme is an explicit Finite Volume technique employing flux-vector splitting and a reviewed Roe-Riemann solver. Source term formulations are employed in a semi-implicit way, including the two-way coupling of the Lagrangian and Eulerian solvers by means of conservative mass and momentum transfers between fluid and solid phases. The model was applied to Sines Port, a major commercial port in Portugal, where two tsunamigenic scenarios are considered: an 8.5 Mw scenario, consistent with the Great Lisbon Earthquake and Tsunami of the 1st November 1755 (Baptista, 2009), and an hypothetical 9.5 Mw worst-case scenario based on the same historical event. Open-ocean propagation of these scenarios were simulated with GeoClaw model from ClawPack (Leveque, 2011). Following previous efforts on the modelling of debris transport by tsunamis in seaports (Conde, 2015), this work discusses the sensitivity of the obtained results with respect to the phenomenological detail of the employed Eulerian-Lagrangian formulation and the resolution of the mesh used in the Eulerian solver. The results have shown that the fluid to debris mass ratio is the key parameter regarding the

  18. Subsonic Ultra Green Aircraft Research

    NASA Technical Reports Server (NTRS)

    Bradley, Marty K.; Droney, Christopher K.

    2011-01-01

    This Final Report summarizes the work accomplished by the Boeing Subsonic Ultra Green Aircraft Research (SUGAR) team in Phase 1, which includes the time period of October 2008 through March 2010. The team consisted of Boeing Research and Technology, Boeing Commercial Airplanes, General Electric, and Georgia Tech. The team completed the development of a comprehensive future scenario for world-wide commercial aviation, selected baseline and advanced configurations for detailed study, generated technology suites for each configuration, conducted detailed performance analysis, calculated noise and emissions, assessed technology risks, and developed technology roadmaps. Five concepts were evaluated in detail: 2008 baseline, N+3 reference, N+3 high span strut braced wing, N+3 gas turbine battery electric concept, and N+3 hybrid wing body. A wide portfolio of technologies was identified to address the NASA N+3 goals. Significant improvements in air traffic management, aerodynamics, materials and structures, aircraft systems, propulsion, and acoustics are needed. Recommendations for Phase 2 concept and technology projects have been identified.

  19. Subsonic and transonic propeller noise

    NASA Astrophysics Data System (ADS)

    Lewy, S.; Gounet, H.

    Models for the noise levels from propellers are discussed, with results compared to in-flight measurements. Methods originally applied to noise from light aircraft are modified and extended to high speed passenger aircraft. Noise emitted from propellers has three components: a monopolar emission due to the air displaced by a blade; a bipolar form from average and fluctuating forces exerted by the blades; and a quadripolar component produced by deformation of the streamlines around the blade profile and defined by the Lighthill tensor. The latter is not a factor in the subsonic regime and can be neglected. Attention is given to a formalism which accounts for the sound level along each band, the frequency harmonics at each blade passage, the number of blades, and the rotation rate. The measured directivities of the two components are described. It is found that the radiated noise levels can be reduced in slow aircraft by lowering the peripheral velocity while keeping the same power with more blades. Calculations including the quadripolar term are necessary for modeling noise levels in transonic propellers.

  20. Locating inefficient links in a large-scale transportation network

    NASA Astrophysics Data System (ADS)

    Sun, Li; Liu, Like; Xu, Zhongzhi; Jie, Yang; Wei, Dong; Wang, Pu

    2015-02-01

    Based on data from geographical information system (GIS) and daily commuting origin destination (OD) matrices, we estimated the distribution of traffic flow in the San Francisco road network and studied Braess's paradox in a large-scale transportation network with realistic travel demand. We measured the variation of total travel time Δ T when a road segment is closed, and found that | Δ T | follows a power-law distribution if Δ T < 0 or Δ T > 0. This implies that most roads have a negligible effect on the efficiency of the road network, while the failure of a few crucial links would result in severe travel delays, and closure of a few inefficient links would counter-intuitively reduce travel costs considerably. Generating three theoretical networks, we discovered that the heterogeneously distributed travel demand may be the origin of the observed power-law distributions of | Δ T | . Finally, a genetic algorithm was used to pinpoint inefficient link clusters in the road network. We found that closing specific road clusters would further improve the transportation efficiency.

  1. Large wood budget and transport dynamics on a large river using radio telemetry

    USGS Publications Warehouse

    Schenk, Edward R.; Moulin, Bertrand; Hupp, Cliff R.; Richte, Jean M.

    2014-01-01

    Despite the abundance of large wood (LW) river studies there is still a lack of understanding of LW transport dynamics on large low gradient rivers. This study used 290 radio frequency identification tagged (RFID) LW and 54 metal (aluminum) tagged LW, to quantify the percent of in-channel LW that moves per year and what variables play a role in LW transport dynamics. Aluminum tags were installed and monitored on LW in-transit during the rising limb of a flood, the mean distance traveled by those pieces during the week was 13.3 river kilometers (km) with a maximum distance of 72 km. RFID tagged LW moved a mean of 11.9 km/yr with a maximum observed at 101.1 km/yr. Approximately 41% of LW low on the bank moves per year. The high rate of transport and distance traveled is likely due to the lack of interaction between LW floating in the channel and the channel boundaries, caused primarily by the width of the channel relative to length of the LW. Approximately 80% of the RFID tags moved past a fixed reader during the highest 20% of river stage per year. LW transport and logjam dynamics are complicated at high flows as pieces form temporary jams that continually expand and contract. Unlike most other studies, key members that create a logjam were defined more by stability than jam size or channel/hydrologic conditions. Finally, using an existing geomorphic database for the river, and data from this study, we were able to develop a comprehensive LW budget showing that 5% of the in-channel LW population turns over each year (input from mass wasting and fluvial erosion equals burial, decomposition, and export out of system) and another 16% of the population moving within the system.

  2. Analysis of separation of the space shuttle orbiter from a large transport airplane

    NASA Technical Reports Server (NTRS)

    Wilhite, A. W.

    1977-01-01

    The feasibility of safely separating the space shuttle orbiter (140A/B) from the top of a large carrier vehicle (the C-5 airplane) at subsonic speeds was investigated. The longitudinal equations of motion for both vehicles were numerically integrated using a digital computer program which incorporates experimentally derived interference aerodynamic data to analyze the separation maneuver for various initial conditions. Separation of the space shuttle orbiter from a carrier vehicle was feasible for a range of dynamic-pressure and flight-path-angle conditions. By using an autopilot, the vehicle attitudes were held constant which ensured separation. Carrier-vehicle engine thrust, landing gear, and spoilers provide some flexibility in the separation maneuver.

  3. 14 CFR 91.1037 - Large transport category airplanes: Turbine engine powered; Limitations; Destination and...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ....1037 Large transport category airplanes: Turbine engine powered; Limitations; Destination and alternate airports. (a) No program manager or any other person may permit a turbine engine powered large transport... and terrain. (c) A program manager or other person flying a turbine engine powered large transport...

  4. 14 CFR 135.385 - Large transport category airplanes: Turbine engine powered: Landing limitations: Destination...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ....385 Large transport category airplanes: Turbine engine powered: Landing limitations: Destination airports. (a) No person operating a turbine engine powered large transport category airplane may take off... this section, no person operating a turbine engine powered large transport category airplane may take...

  5. 14 CFR 135.385 - Large transport category airplanes: Turbine engine powered: Landing limitations: Destination...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ....385 Large transport category airplanes: Turbine engine powered: Landing limitations: Destination airports. (a) No person operating a turbine engine powered large transport category airplane may take off... this section, no person operating a turbine engine powered large transport category airplane may take...

  6. 14 CFR 91.1037 - Large transport category airplanes: Turbine engine powered; Limitations; Destination and...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ....1037 Large transport category airplanes: Turbine engine powered; Limitations; Destination and alternate airports. (a) No program manager or any other person may permit a turbine engine powered large transport... and terrain. (c) A program manager or other person flying a turbine engine powered large transport...

  7. 14 CFR 135.385 - Large transport category airplanes: Turbine engine powered: Landing limitations: Destination...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Large transport category airplanes: Turbine....385 Large transport category airplanes: Turbine engine powered: Landing limitations: Destination airports. (a) No person operating a turbine engine powered large transport category airplane may take...

  8. 14 CFR 135.385 - Large transport category airplanes: Turbine engine powered: Landing limitations: Destination...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Large transport category airplanes: Turbine....385 Large transport category airplanes: Turbine engine powered: Landing limitations: Destination airports. (a) No person operating a turbine engine powered large transport category airplane may take...

  9. 14 CFR 135.385 - Large transport category airplanes: Turbine engine powered: Landing limitations: Destination...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Large transport category airplanes: Turbine....385 Large transport category airplanes: Turbine engine powered: Landing limitations: Destination airports. (a) No person operating a turbine engine powered large transport category airplane may take...

  10. 14 CFR 135.387 - Large transport category airplanes: Turbine engine powered: Landing limitations: Alternate airports.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Large transport category airplanes: Turbine....387 Large transport category airplanes: Turbine engine powered: Landing limitations: Alternate... alternate airport for a turbine engine powered large transport category airplane unless (based on...

  11. 14 CFR 135.387 - Large transport category airplanes: Turbine engine powered: Landing limitations: Alternate airports.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Large transport category airplanes: Turbine....387 Large transport category airplanes: Turbine engine powered: Landing limitations: Alternate... alternate airport for a turbine engine powered large transport category airplane unless (based on...

  12. Solute Transport Dynamics in a Large Hyporheic Corridor System

    NASA Astrophysics Data System (ADS)

    Zachara, J. M.; Chen, X.; Murray, C. J.; Shuai, P.; Rizzo, C.; Song, X.; Dai, H.

    2016-12-01

    A hyporheic corridor is an extended zone of groundwater surface water-interaction that occurs within permeable aquifer sediments in hydrologic continuity with a river. These systems are dynamic and tightly coupled to river stage variations that may occur over variable time scales. Here we describe the behavior of a persistent uranium (U) contaminant plume that exists within the hyporheic corridor of a large, managed river system - the Columbia River. Temporally dense monitoring data were collected for a two year period from wells located within the plume at varying distances up to 400 m from the river shore. Groundwater U originates from desorption of residual U in the lower vadose zone during periods of high river stage and associated elevated water table. U is weakly adsorbed to aquifer sediments because of coarse texture, and along with specific conductance, serves as a tracer of vadose zone source terms, solute transport pathways, and groundwater-surface water mixing. Complex U concentration and specific conductance trends were observed for all wells that varied with distance from the river shoreline and the river hydrograph, although trends for each well were generally repeatable for each year during the monitoring period. Statistical clustering analysis was used to identify four groups of wells that exhibited common trends in dissolved U and specific conductance. A flow and reactive transport code, PFLOTRAN, was implemented within a hydrogeologic model of the groundwater-surface water interaction zone to provide insights on hydrologic processes controlling monitoring trends and cluster behavior. The hydrogeologic model was informed by extensive subsurface characterization, with the spatially variable topography of a basal aquitard being one of several key parameters. Numerical tracer experiments using PFLOTRAN revealed the presence of temporally complex flow trajectories, spatially variable domains of groundwater - river water mixing, and locations of

  13. Effects of winglets on a first-generation jet transport wing. 7: Sideslip effects on winglet loads and selected wing loads at subsonic speeds for a full-span model

    NASA Technical Reports Server (NTRS)

    Meyer, Robert R., Jr.; Covell, Peter F.

    1986-01-01

    The effect of sideslip on winglet loads and selected wing loads was investigated at high and low subsonic Mach numbers. The investigation was conducted in two separate wind tunnel facilities, using two slightly different 0.035-scale full-span models. Results are presented which indicate that, in general, winglet loads as a result of sideslip are analogous to wing loads caused by angle of attack. The center-of-pressure locations on the winglets are somewhat different than might be expected for an analogous wing. The spanwise center of pressure for a winglet tends to be more inboard than for a wing. The most notable chordwise location is a forward center-of-pressure location on the winglet at high sideslip angles. The noted differences between a winglet and an analogous wing are the result of the influence of the wing on the winglet.

  14. Turbulent flow and scalar transport in a large wind farm

    NASA Astrophysics Data System (ADS)

    Porte-Agel, F.; Markfort, C. D.; Zhang, W.

    2012-12-01

    Wind energy is one of the fastest growing sources of renewable energy world-wide, and it is expected that many more large-scale wind farms will be built and cover a significant portion of land and ocean surfaces. By extracting kinetic energy from the atmospheric boundary layer and converting it to electricity, wind farms may affect the transport of momentum, heat, moisture and trace gases (e.g. CO_2) between the atmosphere and the land surface locally and globally. Understanding wind farm-atmosphere interaction is complicated by the effects of turbine array configuration, wind farm size, land-surface characteristics, and atmospheric thermal stability. A wind farm of finite length may be modeled as an added roughness or as a canopy in large-scale weather and climate models. However, it is not clear which analogy is physically more appropriate. Also, surface scalar flux is affected by wind farms and needs to be properly parameterized in meso-scale and/or high-resolution numerical models. Experiments involving model wind farms, with perfectly aligned and staggered configurations, having the same turbine distribution density, were conducted in a thermally-controlled boundary-layer wind tunnel. A neutrally stratified turbulent boundary layer was developed with a surface heat source. Measurements of the turbulent flow and fluxes over and through the wind farm were made using a custom x-wire/cold-wire anemometer; and surface scalar flux was measured with an array of surface-mounted heat flux sensors far within the quasi-developed region of the wind-farm. The turbulence statistics exhibit similar properties to those of canopy-type flows, but retain some characteristics of surface-layer flows in a limited region above the wind farms as well. The flow equilibrates faster and the overall momentum absorption is higher for the staggered compared to the aligned farm, which is consistent with canopy scaling and leads to a larger effective roughness. Although the overall surface

  15. Transport of large particles in flow through porous media

    NASA Astrophysics Data System (ADS)

    Imdakm, A. O.; Sahimi, Muhammad

    1987-12-01

    There is considerable evidence indicating that significant reduction in the efficiency of many processes in porous media, such as enhancing oil recovery, heterogeneous chemical reactions, deep-bed filtration, gel permeation, and liquid chromatography, is due to the reduction in the permeability of the pore space. This reduction is due to the transport of particles, whose sizes are comparable with those of the pores, and the subsequent blocking of the pores by various mechanisms. In this paper we develop a novel Monte Carlo method for theoretical modeling of this phenomenon. Particles of various sizes are injected into the medium, and their migration in the flow field is modeled by a random walk whose transition porbability is proportional to the local pore fluxes. Pores are blocked and their flow capacity is reduced (or vanished) when large particles pass through them (and reduce their flow) or totally block them. The permeability of the medium can ultimately vanish and, therefore, this phenomenon is a percolation process. Various quantities of interest such as the variations of the permeability with process time and the distribution of pore-plugging times are computed. The critical exponent characterizing the vanishing of the permeability near the percolation threshold appears to be different from that of percolation conductivity. The agreement between our results and the available experimental data is excellent.

  16. Unsteady Aerodynamics - Subsonic Compressible Inviscid Case

    NASA Technical Reports Server (NTRS)

    Balakrishnan, A. V.

    1999-01-01

    This paper presents a new analytical treatment of Unsteady Aerodynamics - the linear theory covering the subsonic compressible (inviscid) case - drawing on some recent work in Operator Theory and Functional Analysis. The specific new results are: (a) An existence and uniqueness proof for the Laplace transform version of the Possio integral equation as well as a new closed form solution approximation thereof. (b) A new representation for the time-domain solution of the subsonic compressible aerodynamic equations emphasizing in particular the role of the initial conditions.

  17. 14 CFR 91.805 - Final compliance: Subsonic airplanes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Final compliance: Subsonic airplanes. 91... § 91.805 Final compliance: Subsonic airplanes. Except as provided in §§ 91.809 and 91.811, on and after January 1, 1985, no person may operate to or from an airport in the United States any subsonic...

  18. 14 CFR 91.805 - Final compliance: Subsonic airplanes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Final compliance: Subsonic airplanes. 91... § 91.805 Final compliance: Subsonic airplanes. Except as provided in §§ 91.809 and 91.811, on and after January 1, 1985, no person may operate to or from an airport in the United States any subsonic...

  19. 14 CFR 91.805 - Final compliance: Subsonic airplanes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Final compliance: Subsonic airplanes. 91... § 91.805 Final compliance: Subsonic airplanes. Except as provided in §§ 91.809 and 91.811, on and after January 1, 1985, no person may operate to or from an airport in the United States any subsonic airplane...

  20. 14 CFR 91.805 - Final compliance: Subsonic airplanes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Final compliance: Subsonic airplanes. 91... § 91.805 Final compliance: Subsonic airplanes. Except as provided in §§ 91.809 and 91.811, on and after January 1, 1985, no person may operate to or from an airport in the United States any subsonic airplane...

  1. 14 CFR 91.805 - Final compliance: Subsonic airplanes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Final compliance: Subsonic airplanes. 91... § 91.805 Final compliance: Subsonic airplanes. Except as provided in §§ 91.809 and 91.811, on and after January 1, 1985, no person may operate to or from an airport in the United States any subsonic airplane...

  2. 14 CFR 135.369 - Large transport category airplanes: Reciprocating engine powered: En route limitations: All...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Large transport category airplanes... and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND... Limitations § 135.369 Large transport category airplanes: Reciprocating engine powered: En route...

  3. 14 CFR 135.369 - Large transport category airplanes: Reciprocating engine powered: En route limitations: All...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Large transport category airplanes... and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND... Limitations § 135.369 Large transport category airplanes: Reciprocating engine powered: En route...

  4. Airfoil shape for flight at subsonic speeds

    DOEpatents

    Whitcomb, Richard T.

    1976-01-01

    An airfoil having an upper surface shaped to control flow accelerations and pressure distribution over the upper surface and to prevent separation of the boundary layer due to shock wave formulation at high subsonic speeds well above the critical Mach number. A highly cambered trailing edge section improves overall airfoil lifting efficiency.

  5. 14 CFR 91.1037 - Large transport category airplanes: Turbine engine powered; Limitations; Destination and...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Large transport category airplanes: Turbine....1037 Large transport category airplanes: Turbine engine powered; Limitations; Destination and alternate airports. (a) No program manager or any other person may permit a turbine engine powered large...

  6. 14 CFR 91.1037 - Large transport category airplanes: Turbine engine powered; Limitations; Destination and...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Large transport category airplanes: Turbine....1037 Large transport category airplanes: Turbine engine powered; Limitations; Destination and alternate airports. (a) No program manager or any other person may permit a turbine engine powered large...

  7. 14 CFR 91.1037 - Large transport category airplanes: Turbine engine powered; Limitations; Destination and...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Large transport category airplanes: Turbine....1037 Large transport category airplanes: Turbine engine powered; Limitations; Destination and alternate airports. (a) No program manager or any other person may permit a turbine engine powered large...

  8. Parameterization of Fire Injection Height in Large Scale Transport Model

    NASA Astrophysics Data System (ADS)

    Paugam, R.; Wooster, M.; Atherton, J.; Val Martin, M.; Freitas, S.; Kaiser, J. W.; Schultz, M. G.

    2012-12-01

    The parameterization of fire injection height in global chemistry transport model is currently a subject of debate in the atmospheric community. The approach usually proposed in the literature is based on relationships linking injection height and remote sensing products like the Fire Radiative Power (FRP) which can measure active fire properties. In this work we present an approach based on the Plume Rise Model (PRM) developed by Freitas et al (2007, 2010). This plume model is already used in different host models (e.g. WRF, BRAMS). In its original version, the fire is modeled by: a convective heat flux (CHF; pre-defined by the land cover and evaluated as a fixed part of the total heat released) and a plume radius (derived from the GOES Wildfire-ABBA product) which defines the fire extension where the CHF is homogeneously distributed. Here in our approach the Freitas model is modified, in particular we added (i) an equation for mass conservation, (ii) a scheme to parameterize horizontal entrainment/detrainment, and (iii) a new initialization module which estimates the sensible heat released by the fire on the basis of measured FRP rather than fuel cover type. FRP and Active Fire (AF) area necessary for the initialization of the model are directly derived from a modified version of the Dozier algorithm applied to the MOD14 product. An optimization (using the simulating annealing method) of this new version of the PRM is then proposed based on fire plume characteristics derived from the official MISR plume height project and atmospheric profiles extracted from the ECMWF analysis. The data set covers the main fire region (Africa, Siberia, Indonesia, and North and South America) and is set up to (i) retain fires where plume height and FRP can be easily linked (i.e. avoid large fire cluster where individual plume might interact), (ii) keep fire which show decrease of FRP and AF area after MISR overpass (i.e. to minimize effect of the time period needed for the plume to

  9. Parameterization of Fire Injection Height in Large Scale Transport Model

    NASA Astrophysics Data System (ADS)

    Paugam, r.; Wooster, m.; Freitas, s.; Gonzi, s.; Palmer, p.

    2012-04-01

    The parameterization of fire injection height in global chemistry transport model is currently a subject of debate in the atmospheric community. The approach usually proposed in the literature is based on relationships linking injection height and remote sensing products like the Fire Radiative Power (FRP) which can measure active fire properties. In this work we present an approach based on the Plume Rise Model (PRM) developed by Freitas et al (2007, 2010). This plume model is already used in different host models (e.g. WRF, BRAMS). In its original version, the fire is modelled by: a convective heat flux (CHF; pre-defined by the land cover and evaluated as a fixed part of the total heat released) and a plume radius (derived from the GOES Wildfire-ABBA product) which defines the fire extension where the CHF is homogeneously distributed. Here in our approach the Freitas model is modified. Major modifications are implemented in its initialisation module: (i) CHF and the Active Fire area are directly force from FRP data derived from a modified version of the Dozier algorithm applied to the MOD12 product, (ii) and a new module of the buoyancy flux calculation is implemented instead of the original module based on the Morton Taylor and Turner equation. Furthermore the dynamical core of the plume model is also modified with a new entrainment scheme inspired from latest results from shallow convection parameterization. Optimization and validation of this new version of the Freitas PRM is based on fire plume characteristics derived from the official MISR plume height project and atmospheric profile extracted from the ECMWF analysis. The data set is (i) build up to only keep fires where plume height and FRP can be easily linked (i.e. avoid large fire cluster where individual plume might interact) and (ii) split per fire land cover type to optimize the constant of the buoyancy flux module and the entrainment scheme to different fire regime. Result shows that the new PRM is

  10. Electron turbulence and transport in large magnetic islands

    NASA Astrophysics Data System (ADS)

    Morton, Lucas

    2016-10-01

    Magnetic islands, observed in both reversed-field pinches (RFPs) and tokamaks, often display unexpected turbulence and transport characteristics. For the first time in an RFP, the high repetition rate Thomson scattering diagnostic on MST has captured a 2D image of the rotating electron temperature structure of a magnetic island in a single discharge. MHD modeling using edge magnetic signals implies a 16 cm wide m,n =1,6 tearing mode island which completely overlaps a 5.5 cm n =7 island (12 cm between island centers). The 3D field is partially chaotic, but still reflective of the n =6 island structure. The measured temperature structure matches the shape and location of the n =6 partially chaotic (or `remnant') island. Contrary to the usual assumption that islands have flat internal temperature, the electron temperature is peaked inside the remnant magnetic island due to ohmic heating. The temperature peaking implies a local effective perpendicular conductivity 10-40 m2/s inside the remnant island. This agrees quantitatively with an effective perpendicular conductivity of 16 m2/s estimated using the magnetic diffusion coefficient (evaluated at the electron mean free path) calculated from the modeled chaotic field. Statistical analysis of measurement ensembles with lower time resolution implies that remnant island heating is common in MST discharges. To investigate the role of turbulence near a magnetic island, the 2D structure of long-wavelength density turbulence has been mapped around a large applied static m,n =2,1 L-mode island in the DIII-D tokamak. The turbulence exhibits intriguing spatial structure. Fluctuations are enhanced several-fold (compared to the no-island case) on the inboard side of the X-point, but not on the outboard side of the X-point and are also reduced near the O-point. This work is supported by the NSF and US DOE under DE-FC02-04ER54698, and DE-FG02-89ER53296.

  11. Investigation of transport processes in a large urban estuary

    NASA Astrophysics Data System (ADS)

    Caplow, T.; Schlosser, P.; Ho, D. T.; Santella, N.

    2003-04-01

    The Hudson River drains an area of 35 000 km^2 and terminates in a complex of waterways surrounding New York City. These waterways support the largest metropolitan area and third busiest seaport in the U.S., absorbing a large flux of industrial contaminants and wastewater, as well as accidental spills of oil and chemicals. Traditional approaches to the study of transport processes in New York Harbor include fluorescent dyes, moored current profilers, and numerical models, but these methods are limited by low temporal and spatial resolution and/or uncertain accuracy, particularly with regard to mixing. In July 2001, sulfur hexafluoride (SF_6) was injected into the Hudson River estuary near Newburgh, NY, about 100 km upstream from New York City. The resulting tracer patch was surveyed by boat (average resolution: 400 m) with an automated measurement system. After 13 days, the tracer patch was more than 100 km long. Net advection (0.5 km d-1), longitudinal dispersion (70 ± 4 m^2 s-1) and gas transfer velocity (6.5 ± 0.5 cm h-1) were determined from the tracer data. Tidal motions dominated river flow, and considerable quantities of tracer propagated upstream from the injection site. In July 2002, SF_6 was injected in the inner harbor, a complex of estuarine channels adjacent to the city. The tracer was tracked for 11 days. Due to tidal mixing, the shorter of two channels (9 km and 20 km) that connect with the outer harbor was the dominant seaward pathway, despite subtidal circulation in the opposite direction. As a result of gas transfer and seaward flushing, tracer mass in the inner harbor declined quasi-exponentially with a loss term of 0.29 ± 0.03 day-1. The loss term due to flushing alone (0.13 ± 0.02 day-1) indicated a mean residence time for water and solutes in the inner harbor of 8 days (without gas transfer). Further projects, including an investigation of wastewater fate, are planned within the lower estuary.

  12. Active control transport design criteria

    NASA Technical Reports Server (NTRS)

    Hall, B. M.; Harris, R. B.

    1976-01-01

    Vehicle design considerations for active control applications to subsonic transports are examined. Active control is defined along with those functions which are considered in the study of design criteria. The FAA regulations governing transport aircraft design are briefly discussed.

  13. Interaction between plasma synthetic jet and subsonic turbulent boundary layer

    NASA Astrophysics Data System (ADS)

    Zong, Haohua; Kotsonis, Marios

    2017-04-01

    This paper experimentally investigates the interaction between a plasma synthetic jet (PSJ) and a subsonic turbulent boundary layer (TBL) using a hotwire anemometer and phase-locked particle imaging velocimetry. The PSJ is interacting with a fully developed turbulent boundary layer developing on the flat wall of a square wind tunnel section of 1.7 m length. The Reynolds number based on the freestream velocity (U∞ = 20 m/s) and the boundary layer thickness (δ99 = 34.5 mm) at the location of interaction is 44 400. A large-volume (1696 mm3) three-electrode plasma synthetic jet actuator (PSJA) with a round exit orifice (D = 2 mm) is adopted to produce high-speed (92 m/s) and short-duration (Tjet = 1 ms) pulsed jets. The exit velocity variation of the adopted PSJA in a crossflow is shown to remain almost identical to that in quiescent conditions. However, the flow structures emanating from the interaction between the PSJ and the TBL are significantly different from what were observed in quiescent conditions. In the midspan xy plane (z = 0 mm), the erupted jet body initially follows a wall-normal trajectory accompanied by the formation of a distinctive front vortex ring. After three convective time scales the jet bends to the crossflow, thus limiting the peak penetration depth to approximately 0.58δ99. Comparison of the normalized jet trajectories indicates that the penetration ability of the PSJ is less than steady jets with the same momentum flow velocity. Prior to the jet diminishing, a recirculation region is observed in the leeward side of the jet body, experiencing first an expansion and then a contraction in the area. In the cross-stream yz plane, the signature structure of jets in a crossflow, the counter-rotating vortex pair (CVP), transports high-momentum flow from the outer layer to the near-wall region, leading to a fuller velocity profile and a drop in the boundary layer shape factor (1.3 to 1.2). In contrast to steady jets, the CVP produced by the PSJ

  14. O the Description of Space Plasmas Exhibiting Temperature Anisotropies for Subsonic Flow.

    NASA Astrophysics Data System (ADS)

    Demars, Howard Griffin

    The purpose of this paper was to compare solutions to the bi-Maxwellian based 16-moment transport equations with those obtained from the Maxwellian based 13-moment transport equations for conditions leading to the steady state, subsonic flow of a fully-ionized electron-proton plasma along geomagnetic field lines. An in-depth review of past work in the field of ionospheric temperature anisotropies, covering both theoretical models and experimental observations, was presented first in order to provide a background for and clarify the meaning of the original research to follow. Both the 16-moment and 13-moment sets were expressed in a dipolar coordinate system and numerically integrated along the direction of the geomagnetic field. The comparison was conducted for a range of lower boundary temperatures (2000 -10000 K) and temperature gradients (1-4 K km('-1)) over the altitude range from 1500-13000 km. These boundary parameters are the most important in the subsonic flow regime since they produce different temperature anisotropies and heat flows, which are handled differently in the two formula- tions. The 16-moment set of transport equations, which is based on a zeroth-order bi-Maxwellian (two-temperature) velocity distribution function, can account for large temperature anisotropies and the flow of both parallel and perpendicular thermal energy, while the 13-moment set, which is based on a zeroth-order distribution that is Maxwellian (temperature isotropic), can account for small tem- perature anisotropies and only a total heat flow. For low boundary temperatures (T (TURN) 2000 K) and low boundary temperature gradients ((DEL)T(, )< 2 K km('-1)), the differences between the bi-Maxwellian based 16-moment and Maxwellian based 13-moment solutions were found to be negligibly small. For intermediate boundary temperatures and temperature gradients, both the 16-moment and 13-moment formu- lations predict electron and proton temperature anisotropies with perpendicular

  15. Subsonic Round and Rectangular Twin Jet Flow Effects

    NASA Technical Reports Server (NTRS)

    Bozak, Rick; Wernet, Mark

    2014-01-01

    Subsonic and supersonic aircraft concepts proposed by NASAs Fundamental Aeronautics Program have integrated propulsion systems with asymmetric nozzles. The asymmetry in the exhaust of these propulsion systems creates asymmetric flow and acoustic fields. The flow asymmetries investigated in the current study are from two parallel round, 2:1, and 8:1 aspect ratio rectangular jets at the same nozzle conditions. The flow field was measured with streamwise and cross-stream particle image velocimetry (PIV). A large dataset of single and twin jet flow field measurements was acquired at subsonic jet conditions. The effects of twin jet spacing and forward flight were investigated. For round, 2:1, and 8:1 rectangular twin jets at their closest spacings, turbulence levels between the two jets decreased due to enhanced jet mixing at near static conditions. When the flight Mach number was increased to 0.25, the flow around the twin jet model created a velocity deficit between the two nozzles. This velocity deficit diminished the effect of forward flight causing an increase in turbulent kinetic energy relative to a single jet. Both of these twin jet flow field effects decreased with increasing twin jet spacing relative to a single jet. These variations in turbulent kinetic energy correlate with changes in far-field sound pressure level.

  16. Review of Propulsion Technologies for N+3 Subsonic Vehicle Concepts

    NASA Technical Reports Server (NTRS)

    Ashcraft, Scott W.; Padron, Andres S.; Pascioni, Kyle A.; Stout, Gary W., Jr.; Huff, Dennis L.

    2011-01-01

    NASA has set aggressive fuel burn, noise, and emission reduction goals for a new generation (N+3) of aircraft targeting concepts that could be viable in the 2035 timeframe. Several N+3 concepts have been formulated, where the term "N+3" indicate aircraft three generations later than current state-of-the-art aircraft, "N". Dramatic improvements need to be made in the airframe, propulsion systems, mission design, and the air transportation system in order to meet these N+3 goals. The propulsion system is a key element to achieving these goals due to its major role with reducing emissions, fuel burn, and noise. This report provides an in-depth description and assessment of propulsion systems and technologies considered in the N+3 subsonic vehicle concepts. Recommendations for technologies that merit further research and development are presented based upon their impact on the N+3 goals and likelihood of being operational by 2035.

  17. Large-scale multi-agent transportation simulations

    NASA Astrophysics Data System (ADS)

    Cetin, Nurhan; Nagel, Kai; Raney, Bryan; Voellmy, Andreas

    2002-08-01

    It is now possible to microsimulate the traffic of whole metropolitan areas with 10 million travelers or more, "micro" meaning that each traveler is resolved individually as a particle. In contrast to physics or chemistry, these particles have internal intelligence; for example, they know where they are going. This means that a transportation simulation project will have, besides the traffic microsimulation, modules which model this intelligent behavior. The most important modules are for route generation and for demand generation. Demand is generated by each individual in the simulation making a plan of activities such as sleeping, eating, working, shopping, etc. If activities are planned at different locations, they obviously generate demand for transportation. This however is not enough since those plans are influenced by congestion which initially is not known. This is solved via a relaxation method, which means iterating back and forth between the activities/routes generation and the traffic simulation.

  18. Large Plate CdTe Synthesis by Sealed Vessel Transport

    DTIC Science & Technology

    1983-01-01

    this document are those of the authors and should not be interpreted as repre- senting the official policies, either expressed or implied, *of the...Defense Advanced Research Projects Agency or the U.S. Government." 7I iin_ _ _ _ __ _ __lli___ _ __ _ __ _ __ _ ___I_ _ __ _ __ _ SECURITY CLASSIFICATION Of...VESSEL TRANSPORT 6. PERFORMIMG ORG. REPORT MBER 7. AUTHOR() S. CONTRACT OR GRANT NuMEER(O) A. R. HILTON MDA903-82-C-0159 9. PERFORMING ORGANIZATION

  19. Heavy-flavour transport: from large to small systems

    NASA Astrophysics Data System (ADS)

    Beraudo, A.; De Pace, A.; Monteno, M.; Nardi, M.; Prino, F.

    2016-12-01

    Predictions for heavy-flavour production in relativistic heavy-ion experiments provided by the POWLANG transport setup, including now also an in-medium hadronization model, are displayed, After showing some representative findings for the Au-Au and Pb-Pb cases, a special focus will be devoted to the results obtained in the small systems formed in proton(deuteron)-nucleus collisions, where recent experimental data suggest the possible formation of a medium featuring a collective behaviour.

  20. 14 CFR 36.7 - Acoustical change: Transport category large airplanes and jet airplanes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... airplanes and jet airplanes. 36.7 Section 36.7 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... § 36.7 Acoustical change: Transport category large airplanes and jet airplanes. (a) Applicability. This section applies to all transport category large airplanes and jet airplanes for which an acoustical...

  1. 14 CFR 36.7 - Acoustical change: Transport category large airplanes and jet airplanes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... airplanes and jet airplanes. 36.7 Section 36.7 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... § 36.7 Acoustical change: Transport category large airplanes and jet airplanes. (a) Applicability. This section applies to all transport category large airplanes and jet airplanes for which an acoustical...

  2. 14 CFR 36.7 - Acoustical change: Transport category large airplanes and jet airplanes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... airplanes and jet airplanes. 36.7 Section 36.7 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... § 36.7 Acoustical change: Transport category large airplanes and jet airplanes. (a) Applicability. This section applies to all transport category large airplanes and jet airplanes for which an acoustical...

  3. 14 CFR 135.379 - Large transport category airplanes: Turbine engine powered: Takeoff limitations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Large transport category airplanes: Turbine... category airplanes: Turbine engine powered: Takeoff limitations. (a) No person operating a turbine engine... existing at take- off. (b) No person operating a turbine engine powered large transport category...

  4. 14 CFR 135.379 - Large transport category airplanes: Turbine engine powered: Takeoff limitations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Large transport category airplanes: Turbine... category airplanes: Turbine engine powered: Takeoff limitations. (a) No person operating a turbine engine... existing at take- off. (b) No person operating a turbine engine powered large transport category...

  5. 14 CFR 135.379 - Large transport category airplanes: Turbine engine powered: Takeoff limitations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Large transport category airplanes: Turbine... category airplanes: Turbine engine powered: Takeoff limitations. (a) No person operating a turbine engine... existing at take- off. (b) No person operating a turbine engine powered large transport category...

  6. 14 CFR 135.367 - Large transport category airplanes: Reciprocating engine powered: Takeoff limitations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Large transport category airplanes... AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.367 Large transport category airplanes: Reciprocating engine powered: Takeoff limitations. (a)...

  7. 14 CFR 135.367 - Large transport category airplanes: Reciprocating engine powered: Takeoff limitations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Large transport category airplanes... AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.367 Large transport category airplanes: Reciprocating engine powered: Takeoff limitations. (a)...

  8. 14 CFR 135.365 - Large transport category airplanes: Reciprocating engine powered: Weight limitations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Large transport category airplanes... PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.365 Large transport category airplanes: Reciprocating engine powered: Weight limitations. (a) No person may take off...

  9. 14 CFR 135.365 - Large transport category airplanes: Reciprocating engine powered: Weight limitations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Large transport category airplanes... PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.365 Large transport category airplanes: Reciprocating engine powered: Weight limitations. (a) No person may take off...

  10. 14 CFR 135.365 - Large transport category airplanes: Reciprocating engine powered: Weight limitations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Large transport category airplanes... PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.365 Large transport category airplanes: Reciprocating engine powered: Weight limitations. (a) No person may take off a...

  11. 14 CFR 135.367 - Large transport category airplanes: Reciprocating engine powered: Takeoff limitations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Large transport category airplanes... AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.367 Large transport category airplanes: Reciprocating engine powered: Takeoff limitations. (a) No...

  12. 14 CFR 135.367 - Large transport category airplanes: Reciprocating engine powered: Takeoff limitations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Large transport category airplanes... AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.367 Large transport category airplanes: Reciprocating engine powered: Takeoff limitations. (a) No...

  13. 14 CFR 135.367 - Large transport category airplanes: Reciprocating engine powered: Takeoff limitations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Large transport category airplanes... AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.367 Large transport category airplanes: Reciprocating engine powered: Takeoff limitations. (a) No...

  14. 14 CFR 135.365 - Large transport category airplanes: Reciprocating engine powered: Weight limitations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Large transport category airplanes... PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.365 Large transport category airplanes: Reciprocating engine powered: Weight limitations. (a) No person may take off a...

  15. Aeropropulsion 1987. Session 5: Subsonic Propulsion Technology

    NASA Technical Reports Server (NTRS)

    1987-01-01

    NASA is conducting aeropropulsion research over a broad range of Mach numbers. In addition to the high-speed propulsion research described, major progress was recorded in research aimed at the subsonic flight regimes of interest to many commercial and military users. Recent progress and future directions in such areas as small engine technology, rotorcraft transmissions, icing, Hot Section Technology (HOST) and the Advanced Turboprop Program (ATP) are covered.

  16. Flow quality measurements in compressible subsonic flows

    NASA Technical Reports Server (NTRS)

    Stainback, P. Calvin; Johnson, Charles B.

    1987-01-01

    The purpose is to re-examine the heat transfer from a hot-wire probe in the compressible subsonic flow regime; describe the three-wire hot-wire probe calibration and data reduction techniques used to measure the velocity, density, and total temperature fluctuation; and present flow quality results obtained in the Langley 0.3 meter Transonic Cryogenic Wind Tunnel and in flight with the NASA JetStar from the same three-wire hot-wire probe.

  17. Wind tunnel investigation of a large scale 35 deg swept wing jet transport model with an external blowing triple slotted flap

    NASA Technical Reports Server (NTRS)

    Aoyagi, K.; Hall, L. P.; Falarski, M. D.

    1972-01-01

    An investigation was conducted to determine the aerodynamic characteristics of a large-scale subsonic jet transport model with an externally jet-augmented flap system that would augment lift and provide direct-lift control. The model had a 35 deg swept wing of aspect ratio 7.82 and two side-by-side engines mounted on a single pylon under each wing close to the fuselage. The lift of the flap system was augmented by jet engine exhaust impingement on the triple-slotted flap surfaces. The rearmost flap provided direct lift control. Results were obtained for several combinations of flap deflections at gross thrust coefficients from 0 to 2.0. Three-component longitudinal data are presented with four engines operating. Limited longitudinal and lateral data are presented for asymmetric and symmetric thrust conditions with three engines operating. For the same overall flap deflection, lift coefficient and maximum lift coefficient were improved 13 and 7 percent compared to coefficients obtained with a double-slotted flap configuration. A maximum lift coefficient of 6.3 was obtained at a gross thrust coefficient of 2.0. At the same flap deflection lateral and directional trim moment requirements with an engine inoperative were reduced 55 and 33 percent, respectively, compared to those with the engines located farther outboard on the wing. Trim moment requirements in pitch were also reduced significantly. However, pitching-moment instability occurred and increased with gross thrust coefficient.

  18. Large tropical river mouth sediment-transport dynamics and linkages to coastal sediment transport and deposition

    NASA Astrophysics Data System (ADS)

    Ogston, A. S.; Nowacki, D. J.; Fricke, A. T.; Marks, J.; Nittrouer, C. A.; Souza Filho, P. W.; Van, T. P. D., Jr.

    2014-12-01

    Rivers are the largest suppliers of particulate material to the world ocean, and we must understand the dynamics of tidal river and shallow coastal environments in order to contrast and constrain the sediment budgets of major rivers and their adjacent marine sinks. Studies in large tropical tidal rivers elucidate the processes in these regions that modify the source signal of sediment particles to nearshore environments and vegetated shorelines. Here we focus on processes within the river mouth region of the Amazon and Mekong tidal rivers in order to understand the modulation of sediment-transport signals (magnitude, grain size, pathways) between the river mouth regions and coastal environments. The immense Amazon River mouth experiences no salinity effects (e.g., buoyancy driven flows, physiochemical aggregation) as estuarine processes occur offshore. Mouth channel-bed morphology is variable, and although near surface suspended-sediment concentration (SSC) is relatively constant across the 15-km distributary width, near-bed SSC ranges widely over the tidal cycle depending on sub-channel sediment routing. Sediment pathways differ between ebb and flood conditions inducing a spatially and temporally heterogeneous supply of sediment to the nearshore. In the Mekong River, the mouth region changes from salt-wedge conditions to a partially mixed estuary with seasonal discharge, and there has been an anthropogenic reduction in connections between river and intertidal floodplains. SSC varies throughout the water column and is seasonally modified by estuarine processes. Differences between ebb and flood flows and sediment pathways within and between distributary channels are important to the overall sediment budget, and water-column processes seasonally modify the characteristics of the river bed. These two river-mouth systems differ in channel morphology and sediment-transport mechanisms. Both systems, however, deliver sediment to the nearshore in a spatially and

  19. Far-Field Turbulent Vortex-Wake/Exhaust Plume Interaction for Subsonic and HSCT Airplanes

    NASA Technical Reports Server (NTRS)

    Kandil, Osama A.; Adam, Ihab; Wong, Tin-Chee

    1996-01-01

    Computational study of the far-field turbulent vortex-wake/exhaust plume interaction for subsonic and high speed civil transport (HSCT) airplanes is carried out. The Reynolds-averaged Navier-Stokes (NS) equations are solved using the implicit, upwind, Roe-flux-differencing, finite-volume scheme. The two-equation shear stress transport model of Menter is implemented with the NS solver for turbulent-flow calculation. For the far-field study, the computations of vortex-wake interaction with the exhaust plume of a single engine of a Boeing 727 wing in a holding condition and two engines of an HSCT in a cruise condition are carried out using overlapping zonal method for several miles downstream. These results are obtained using the computer code FTNS3D. The results of the subsonic flow of this code are compared with those of a parabolized NS solver known as the UNIWAKE code.

  20. Evaluation of the Advanced Subsonic Technology Program Noise Reduction Benefits

    NASA Technical Reports Server (NTRS)

    Golub, Robert A.; Rawls, John W., Jr.; Russell, James W.

    2005-01-01

    This report presents a detailed evaluation of the aircraft noise reduction technology concepts developed during the course of the NASA/FAA Advanced Subsonic Technology (AST) Noise Reduction Program. In 1992, NASA and the FAA initiated a cosponsored, multi-year program with the U.S. aircraft industry focused on achieving significant advances in aircraft noise reduction. The program achieved success through a systematic development and validation of noise reduction technology. Using the NASA Aircraft Noise Prediction Program, the noise reduction benefit of the technologies that reached a NASA technology readiness level of 5 or 6 were applied to each of four classes of aircraft which included a large four engine aircraft, a large twin engine aircraft, a small twin engine aircraft and a business jet. Total aircraft noise reductions resulting from the implementation of the appropriate technologies for each class of aircraft are presented and compared to the AST program goals.

  1. Atmospheric Effects of Subsonic Aircraft: Interim Assessment Report of the Advanced Subsonic Technology Program

    NASA Technical Reports Server (NTRS)

    Friedl, Randall R. (Editor)

    1997-01-01

    This first interim assessment of the subsonic assessment (SASS) project attempts to summarize concisely the status of our knowledge concerning the impacts of present and future subsonic aircraft fleets. It also highlights the major areas of scientific uncertainty, through review of existing data bases and model-based sensitivity studies. In view of the need for substantial improvements in both model formulations and experimental databases, this interim assessment cannot provide confident numerical predictions of aviation impacts. However, a number of quantitative estimates are presented, which provide some guidance to policy makers.

  2. Efficient algorithms for large-scale quantum transport calculations

    NASA Astrophysics Data System (ADS)

    Brück, Sascha; Calderara, Mauro; Bani-Hashemian, Mohammad Hossein; VandeVondele, Joost; Luisier, Mathieu

    2017-08-01

    Massively parallel algorithms are presented in this paper to reduce the computational burden associated with quantum transport simulations from first-principles. The power of modern hybrid computer architectures is harvested in order to determine the open boundary conditions that connect the simulation domain with its environment and to solve the resulting Schrödinger equation. While the former operation takes the form of an eigenvalue problem that is solved by a contour integration technique on the available central processing units (CPUs), the latter can be cast into a linear system of equations that is simultaneously processed by SplitSolve, a two-step algorithm, on general-purpose graphics processing units (GPUs). A significant decrease of the computational time by up to two orders of magnitude is obtained as compared to standard solution methods.

  3. Large scale Wyoming transportation data: a resource planning tool

    USGS Publications Warehouse

    O'Donnell, Michael S.; Fancher, Tammy S.; Freeman, Aaron T.; Ziegler, Abra E.; Bowen, Zachary H.; Aldridge, Cameron L.

    2014-01-01

    The U.S. Geological Survey Fort Collins Science Center created statewide roads data for the Bureau of Land Management Wyoming State Office using 2009 aerial photography from the National Agriculture Imagery Program. The updated roads data resolves known concerns of omission, commission, and inconsistent representation of map scale, attribution, and ground reference dates which were present in the original source data. To ensure a systematic and repeatable approach of capturing roads on the landscape using on-screen digitizing from true color National Agriculture Imagery Program imagery, we developed a photogrammetry key and quality assurance/quality control protocols. Therefore, the updated statewide roads data will support the Bureau of Land Management’s resource management requirements with a standardized map product representing 2009 ground conditions. The updated Geographic Information System roads data set product, represented at 1:4,000 and +/- 10 meters spatial accuracy, contains 425,275 kilometers within eight attribute classes. The quality control of these products indicated a 97.7 percent accuracy of aspatial information and 98.0 percent accuracy of spatial locations. Approximately 48 percent of the updated roads data was corrected for spatial errors of greater than 1 meter relative to the pre-existing road data. Twenty-six percent of the updated roads involved correcting spatial errors of greater than 5 meters and 17 percent of the updated roads involved correcting spatial errors of greater than 9 meters. The Bureau of Land Management, other land managers, and researchers can use these new statewide roads data set products to support important studies and management decisions regarding land use changes, transportation and planning needs, transportation safety, wildlife applications, and other studies.

  4. The sediment and phosphorus transport in a large scale study

    NASA Astrophysics Data System (ADS)

    Bauer, Miroslav; Krása, Josef; Dostál, Tomáš; Jáchymová, Barbora

    2017-04-01

    In the name of the Water framework directive (2000/60/ES), there exists the demand to improve quality of water bodies. Basically, pollution of the flowing or stagnant water bodies comes from point and diffuse sources. To find the balance of point (mainly urban areas) and diffuse sources (drainage - N and soil erosion and sediment transport - P) in the scale of Moldau catchment is the task of the project. The area of interest is Moldau river catchment (29.500 km2) has been modelled with fully distributed approach of the WaTEM/SEDEM model. The model estimates the soil erosion as well as sediment a phosphorus transport through the river network. The results are combined with estimation of bounded nitrogen originated from drainage systems in agricultural landscape. The modelling has been done within three levels of accuracy. The simulation scale itself is defined by 10 m elements resolution with critical points net each approximately 300m in the river net (116.000 points). Subsequently, results were aggregated for sub-catchments of 4th order (ca 5 - 15 km2 each = almost 3000 individual sub-catchments) and sub-catchments of 3rd order = ca 400 sub-catchments). Each water reservoir in the system (larger than 0.25 hectares in the area) has been included, which count more than 12.000 reservoirs. The presented approach will be further use by Moldau river catchment managers for the planning of protection and elimination of the pollution in Moldau river catchment. This will lead to localize 3000 highly endangered hot spots which threaten the water bodies significantly. In this localities a detailed modelling and designing of the protection will be done. The research activities had been supported by QJ330118, SGS14/180/OHK1/3T/11, SGS17/090/OHK1/3T/11 grants.

  5. Analysis of supersonic combustion flow fields with embedded subsonic regions

    NASA Technical Reports Server (NTRS)

    Dash, S.; Delguidice, P.

    1972-01-01

    The viscous characteristic analysis for supersonic chemically reacting flows was extended to include provisions for analyzing embedded subsonic regions. The numerical method developed to analyze this mixed subsonic-supersonic flow fields is described. The boundary conditions are discussed related to the supersonic-subsonic and subsonic-supersonic transition, as well as a heuristic description of several other numerical schemes for analyzing this problem. An analysis of shock waves generated either by pressure mismatch between the injected fluid and surrounding flow or by chemical heat release is also described.

  6. Large-scale transport across narrow gaps in rod bundles

    SciTech Connect

    Guellouz, M.S.; Tavoularis, S.

    1995-09-01

    Flow visualization and how-wire anemometry were used to investigate the velocity field in a rectangular channel containing a single cylindrical rod, which could be traversed on the centreplane to form gaps of different widths with the plane wall. The presence of large-scale, quasi-periodic structures in the vicinity of the gap has been demonstrated through flow visualization, spectral analysis and space-time correlation measurements. These structures are seen to exist even for relatively large gaps, at least up to W/D=1.350 (W is the sum of the rod diameter, D, and the gap width). The above measurements appear to compatible with the field of a street of three-dimensional, counter-rotating vortices, whose detailed structure, however, remains to be determined. The convection speed and the streamwise spacing of these vortices have been determined as functions of the gap size.

  7. Molecular transport through large-diameter DNA nanopores.

    PubMed

    Krishnan, Swati; Ziegler, Daniela; Arnaut, Vera; Martin, Thomas G; Kapsner, Korbinian; Henneberg, Katharina; Bausch, Andreas R; Dietz, Hendrik; Simmel, Friedrich C

    2016-09-23

    DNA-based nanopores are synthetic biomolecular membrane pores, whose geometry and chemical functionality can be tuned using the tools of DNA nanotechnology, making them promising molecular devices for applications in single-molecule biosensing and synthetic biology. Here we introduce a large DNA membrane channel with an ≈4 nm diameter pore, which has stable electrical properties and spontaneously inserts into flat lipid bilayer membranes. Membrane incorporation is facilitated by a large number of hydrophobic functionalizations or, alternatively, streptavidin linkages between biotinylated channels and lipids. The channel displays an Ohmic conductance of ≈3 nS, consistent with its size, and allows electrically driven translocation of single-stranded and double-stranded DNA analytes. Using confocal microscopy and a dye influx assay, we demonstrate the spontaneous formation of membrane pores in giant unilamellar vesicles. Pores can be created both in an outside-in and an inside-out configuration.

  8. Molecular transport through large-diameter DNA nanopores

    NASA Astrophysics Data System (ADS)

    Krishnan, Swati; Ziegler, Daniela; Arnaut, Vera; Martin, Thomas G.; Kapsner, Korbinian; Henneberg, Katharina; Bausch, Andreas R.; Dietz, Hendrik; Simmel, Friedrich C.

    2016-09-01

    DNA-based nanopores are synthetic biomolecular membrane pores, whose geometry and chemical functionality can be tuned using the tools of DNA nanotechnology, making them promising molecular devices for applications in single-molecule biosensing and synthetic biology. Here we introduce a large DNA membrane channel with an ~4 nm diameter pore, which has stable electrical properties and spontaneously inserts into flat lipid bilayer membranes. Membrane incorporation is facilitated by a large number of hydrophobic functionalizations or, alternatively, streptavidin linkages between biotinylated channels and lipids. The channel displays an Ohmic conductance of ~3 nS, consistent with its size, and allows electrically driven translocation of single-stranded and double-stranded DNA analytes. Using confocal microscopy and a dye influx assay, we demonstrate the spontaneous formation of membrane pores in giant unilamellar vesicles. Pores can be created both in an outside-in and an inside-out configuration.

  9. Molecular transport through large-diameter DNA nanopores

    PubMed Central

    Krishnan, Swati; Ziegler, Daniela; Arnaut, Vera; Martin, Thomas G.; Kapsner, Korbinian; Henneberg, Katharina; Bausch, Andreas R.; Dietz, Hendrik; Simmel, Friedrich C.

    2016-01-01

    DNA-based nanopores are synthetic biomolecular membrane pores, whose geometry and chemical functionality can be tuned using the tools of DNA nanotechnology, making them promising molecular devices for applications in single-molecule biosensing and synthetic biology. Here we introduce a large DNA membrane channel with an ≈4 nm diameter pore, which has stable electrical properties and spontaneously inserts into flat lipid bilayer membranes. Membrane incorporation is facilitated by a large number of hydrophobic functionalizations or, alternatively, streptavidin linkages between biotinylated channels and lipids. The channel displays an Ohmic conductance of ≈3 nS, consistent with its size, and allows electrically driven translocation of single-stranded and double-stranded DNA analytes. Using confocal microscopy and a dye influx assay, we demonstrate the spontaneous formation of membrane pores in giant unilamellar vesicles. Pores can be created both in an outside-in and an inside-out configuration. PMID:27658960

  10. Space transportation booster engine thrust chamber technology, large scale injector

    NASA Technical Reports Server (NTRS)

    Schneider, J. A.

    1993-01-01

    The objective of the Large Scale Injector (LSI) program was to deliver a 21 inch diameter, 600,000 lbf thrust class injector to NASA/MSFC for hot fire testing. The hot fire test program would demonstrate the feasibility and integrity of the full scale injector, including combustion stability, chamber wall compatibility (thermal management), and injector performance. The 21 inch diameter injector was delivered in September of 1991.

  11. An Investigation of Landing-Contact Conditions for Two Large Turbojet Transports and a Turboprop Transport During Routine Daylight Operations

    NASA Technical Reports Server (NTRS)

    Stickle, Joseph W.

    1961-01-01

    The National Aeronautics and Space Administration has recently completed a statistical investigation of landing-contact conditions for two large turbojet transports and a turboprop transport landing on a dry runway during routine daylight operations at the Los Angeles International Airport. Measurements were made to obtain vertical velocity, airspeed, rolling velocity, bank angle, and distance from the runway threshold, just prior to ground contact. The vertical velocities at touchdown for one of the turbojet airplanes measured in this investigation were essentially the same as those measured on the same type of airplane during a similar investigation (see NASA Technical Note D-527) conducted approximately 8 months earlier. Thus, it appeared that 8 months of additional pilot experience has had no noticeable tendency toward lowering the vertical velocities of this transport. Distributions of vertical velocities for the turbojet transports covered in this investigation were similar and considerably higher than'those for the turboprop transport. The data for the turboprop transport were in good agreement with the data for the piston-engine transports (see NACA Report 1214 and NASA Technical Note D-147) for all the measured parameters. For the turbojet transports, 1 landing in 100 would be expected to equal or exceed a vertical velocity of approximately 4.2 ft/sec; whereas, for the turboprop transport, 1 landing in 100 would be expected to equal or exceed 3.2 ft/sec. The mean airspeeds at touchdown for the three transports ranged from 22.5 percent to 26.6 percent above the stalling speed. Rolling velocities for the turbojet transports were considerably higher than those for the turboprop transport. Distributions of bank angles at contact for the three transports were similar. For each type of airplane, 1 landing in 100 would be expected to equal or exceed a bank angle at touchdown of approximately 3.0 deg. Distributions of touchdown distances for the three transports

  12. Monitoring Large-Scale Sediment Transport Dynamics with Multibeam Sonar

    NASA Astrophysics Data System (ADS)

    Parsons, D. R.; Simmons, S. M.; Best, J. L.; Keevil, G. M.; Oberg, K.; Czuba, J. A.

    2009-05-01

    Multibeam Echo-Sounder systems have developed rapidly over recent decades and are routinely deployed to provide high-resolution bathymetric information in and range of environments. Modern data handling and storage technologies now facilitate the logging of the raw acoustic back-scatter information that was previously discarded by these systems. This paper describes methodologies that exploit this logging capability to quantify both the concentration and dynamics of suspended sediment within the water column. This development provides a multi-purpose tool for the holistic surveying of sediment transport dynamics by imaging suspended sediment concentration, the associated flows and providing concurrent high-resolution bathymetry. Results obtained a RESON 7125 MBES are presented from both well constrained dock-side testing and full field deployment over dune bedforms in the Mississippi. The capacity of the system to image suspended sediment structures is demonstrated and a novel methodology for estimating 2D flow velocities, based on frame cross-correlation methods, is introduced. The results demonstrate the capability of MBES systems to successfully map spatial and temporal variations in suspended sediment concentration throughout a 2D swath and application of the velocity estimation algorithms allow real-time holistic monitoring of turbulent flow processes and suspended sediment fluxes at a scale previously unrealisable. Turbulent flow over a natural dune bedform on the Mississippi is used to highlight the process information provided and the insights that can be gleaned for this technical development.

  13. On the efficiency of transportation systems in large cities

    NASA Astrophysics Data System (ADS)

    Costa, L. da F.; Travençolo, B. A. N.; Viana, M. P.; Strano, E.

    2010-07-01

    We report an analysis of the accessibility between different locations in big cities, which is illustrated with respect to London and Paris. The effects of the respective underground systems in facilitating more uniform access to diverse places are also quantified and investigated. It is shown that London and Paris have markedly different patterns of accessibility, as a consequence of the number of bridges and large parks of London, and that in both cases the respective underground systems imply in general, thought in distinct manners, an increase of accessibility.

  14. Subsonic Performance of Ejector Systems

    NASA Astrophysics Data System (ADS)

    Weil, Samuel

    Combined cycle engines combining scramjets with turbo jets or rockets can provide efficient hypersonic flight. Ejectors have the potential to increase the thrust and efficiency of combined cycle engines near static conditions. A computer code was developed to support the design of a small-scale, turbine-based combined cycle demonstrator with an ejector, built around a commercially available turbojet engine. This code was used to analyze the performance of an ejector system built around a micro-turbojet. With the use of a simple ejector, net thrust increases as large as 20% over the base engine were predicted. Additionally the specific fuel consumption was lowered by 10%. Increasing the secondary to primary area ratio of the ejector lead to significant improvements in static thrust, specific fuel consumption (SFC), and propulsive efficiency. Further ejector performance improvements can be achieved by using a diffuser. Ejector performance drops off rapidly with increasing Mach number. The ejector has lower thrust and higher SFC than the turbojet core at Mach numbers above 0.2. When the nozzle chokes a significant drop in ejector performance is seen. When a diffuser is used, higher Mach numbers lead to choking in the mixer and a shock in the nozzle causing a significant decrease in ejector performance. Evaluation of different turbo jets shows that ejector performance depends significantly on the properties of the turbojet. Static thrust and SFC improvements can be achieved with increasing ejector area for all engines, but size of increase and change in performance at higher Mach numbers depend heavily on the turbojet. The use of an ejector in a turbine based combined cycle configuration also increases performance at static conditions with a thrust increase of 5% and SFC decrease of 5% for the tested configuration.

  15. Large sized non-uniform sediment transport at high capacity on steep slopes

    NASA Astrophysics Data System (ADS)

    Fu, X.; Zhang, L.; Duan, J. G.

    2015-12-01

    Transport of large-sized particles such as cobbles in steep streams still remains poorly understood in spite of its importance in mountain stream morphdynamics. Here we explored the law of cobble transport and the effect of cobble existence on gravel bed material transport, using flume experiments with a steep slope (4.9%) and water and sediment constantly supplying. The experiments were conducted in an 8 m long and 0.6 m wide circulating flume with the maximal size up to 90 mm and cobble concentrations in the sediment bed ranging from 22 percent to 6 percent. The sediment transport rate is on the order of 1000 g/m/s, which could be taken as high rate transport compared with existing researches. Bed load transport rate and flow variables were measured after the flume reached an equilibrium state. Bed surface topography was also measured by applying Kinect range camera before and after each run in order to analyze the fractal characteristics of the bed surface under different flow conditions. Critical shear stress of each size friction was estimated from the reference transport method (RTM) and a new hiding function was recommended. Preliminary results show that the bed was nearly in an equal mobility transport regime. We then plot dimensionless fractional transport rate versus dimensionless shear stress and assess the existing bed load transport formulas of non-uniform sediments for their applicability at high sediment transport capacity. This study contributes to the comprehension of high rate sediment transport on steep slopes.

  16. Rectangular subsonic jet flow field measurements

    NASA Technical Reports Server (NTRS)

    Morrison, Gerald L.; Swan, David H.

    1990-01-01

    Flow field measurements of three subsonic rectangular cold air jets are presented. The three cases had aspect ratios of 1x2, 1x4 at a Mach number of 0.09 and an aspect ratio of 1x2 at a Mach number of 0.9. All measurements were made using a 3-D laser Doppler anemometer system. The data includes the mean velocity vector, all Reynolds stress tensor components, turbulent kinetic energy and velocity correlation coefficients. The data are presented in tabular and graphical form. No analysis of the measured data or comparison to other published data is made.

  17. 14 CFR 91.853 - Final compliance: Civil subsonic airplanes.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Final compliance: Civil subsonic airplanes... Noise Limits § 91.853 Final compliance: Civil subsonic airplanes. Except as provided in § 91.873, after... airplane subject to § 91.801(c) of this subpart, unless that airplane has been shown to comply with Stage...

  18. 14 CFR 91.853 - Final compliance: Civil subsonic airplanes.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Final compliance: Civil subsonic airplanes... Noise Limits § 91.853 Final compliance: Civil subsonic airplanes. Except as provided in § 91.873, after... airplane subject to § 91.801(c) of this subpart, unless that airplane has been shown to comply with Stage...

  19. 14 CFR 91.853 - Final compliance: Civil subsonic airplanes.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Final compliance: Civil subsonic airplanes... Noise Limits § 91.853 Final compliance: Civil subsonic airplanes. Except as provided in § 91.873, after... airplane subject to § 91.801(c) of this subpart, unless that airplane has been shown to comply with Stage 3...

  20. 14 CFR 91.853 - Final compliance: Civil subsonic airplanes.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Final compliance: Civil subsonic airplanes... Noise Limits § 91.853 Final compliance: Civil subsonic airplanes. Except as provided in § 91.873, after... airplane subject to § 91.801(c) of this subpart, unless that airplane has been shown to comply with Stage 3...

  1. 14 CFR 91.853 - Final compliance: Civil subsonic airplanes.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Final compliance: Civil subsonic airplanes... Noise Limits § 91.853 Final compliance: Civil subsonic airplanes. Except as provided in § 91.873, after... airplane subject to § 91.801(c) of this subpart, unless that airplane has been shown to comply with Stage 3...

  2. FPGA development for high altitude subsonic parachute testing

    NASA Technical Reports Server (NTRS)

    Kowalski, James E.; Gromov, Konstantin G.; Konefat, Edward H.

    2005-01-01

    This paper describes a rapid, top down requirements-driven design of a Field Programmable Gate Array (FPGA) used in an Earth qualification test program for a new Mars subsonic parachute. The FPGA is used to process and control storage of telemetry data from multiple sensors throughout launch, ascent, deployment and descent phases of the subsonic parachute test.

  3. FPGA development for high altitude subsonic parachute testing

    NASA Technical Reports Server (NTRS)

    Kowalski, James E.; Konefat, Edward H.; Gromovt, Konstantin

    2005-01-01

    This paper describes a rapid, top down requirements-driven design of an FPGA used in an Earth qualification test program for a new Mars subsonic parachute. The FPGA is used to process and store data from multiple sensors at multiple rates during launch, ascent, deployment and descent phases of the subsonic parachute test.

  4. High altitude subsonic parachute field programmable gate array

    NASA Technical Reports Server (NTRS)

    Kowalski, James E.; Gromov, Konstantin; Konefat, Edward H.

    2005-01-01

    This paper describes a rapid, top down requirements-driven design of an FPGA used in an Earth qualification test program for a new Mars subsonic parachute. The FPGA is used to process and control storage of telemetry data from multiple sensors throughout; launch, ascent, deployment and descent phases of the subsonic parachute test.

  5. Large internal waves in Massachusetts Bay transport sediments offshore

    USGS Publications Warehouse

    Butman, B.; Alexander, P.S.; Scotti, A.; Beardsley, R.C.; Anderson, S.P.

    2006-01-01

    A field experiment was carried out in Massachusetts Bay in August 1998 to assess the role of large-amplitude internal waves (LIWs) in resuspending bottom sediments. The field experiment consisted of a four-element moored array extending from just west of Stellwagen Bank (90-m water depth) across Stellwagen Basin (85- and 50-m water depth) to the coast (24-m water depth). The LIWs were observed in packets of 5–10 waves, had periods of 5–10 min and wavelengths of 200–400 m, and caused downward excursions of the thermocline of as much as 30 m. At the 85-m site, the current measured 1 m above bottom (mab) typically increased from near 0 to 0.2 m/s offshore in a few minutes upon arrival of the LIWs. At the 50-m site, the near-bottom offshore flow measured 6 mab increased from about 0.1 to 0.4–0.6 m/s upon arrival of the LIWs and remained offshore in the bottom layer for 1–2 h. The near-bottom currents associated with the LIWs, in concert with the tidal currents, were directed offshore and sufficient to resuspend the bottom sediments at both the 50- and 85-m sites. When LIWs are present, they may resuspend sediments for as long as 5 hours each tidal cycle as they travel westward across Stellwagen Basin. At 85-m water depth, resuspension associated with LIWs is estimated to occur for about 0.4 days each summer, about the same amount of time as caused by surface waves.

  6. On the Importance of Very Light Internally Subsonic AGN Jets in Radio-mode AGN Feedback

    NASA Astrophysics Data System (ADS)

    Guo, Fulai

    2016-07-01

    Radio-mode active galactic nucleus (AGN) feedback plays a key role in the evolution of galaxy groups and clusters. Its physical origin lies in the kiloparsec-scale interaction of AGN jets with the intracluster medium. Large-scale jet simulations often initiate light internally supersonic jets with density contrast 0.01 < η < 1. Here we argue for the first time for the importance of very light (η < 0.01) internally subsonic jets. We investigated the shapes of young X-ray cavities produced in a suite of hydrodynamic simulations, and found that bottom-wide cavities are always produced by internally subsonic jets, while internally supersonic jets inflate cylindrical, center-wide, or top-wide cavities. We found examples of real cavities with shapes analogous to those inflated in our simulations by internally subsonic and internally supersonic jets, suggesting a dichotomy of AGN jets according to their internal Mach numbers. We further studied the long-term cavity evolution, and found that old cavities resulted from light jets spread along the jet direction, while those produced by very light jets are significantly elongated along the perpendicular direction. The northwestern ghost cavity in Perseus is pancake shaped, providing tentative evidence for the existence of very light jets. Our simulations show that very light internally subsonic jets decelerate faster and rise much slower in the intracluster medium than light internally supersonic jets, possibly depositing a larger fraction of jet energy to cluster cores and alleviating the problem of low coupling efficiencies found previously. The internal Mach number points to the jet’s energy content, and internally subsonic jets are energetically dominated by non-kinetic energy, such as thermal energy, cosmic rays, or magnetic fields.

  7. An Analytical Assessment of NASA's N(+)1 Subsonic Fixed Wing Project Noise Goal

    NASA Technical Reports Server (NTRS)

    Berton, Jeffrey J.; Envia, Edmane; Burley, Casey L.

    2010-01-01

    The Subsonic Fixed Wing Project of NASA s Fundamental Aeronautics Program has adopted a noise reduction goal for new, subsonic, single-aisle, civil aircraft expected to replace current 737 and A320 airplanes. These so-called "N+1" aircraft--designated in NASA vernacular as such since they will follow the current, in-service, "N" airplanes--are hoped to achieve certification noise goal levels of 32 cumulative EPNdB under current Stage 4 noise regulations. A notional, N+1, single-aisle, twinjet transport with ultrahigh bypass ratio turbofan engines is analyzed in this study using NASA software and methods. Several advanced noise-reduction technologies are empirically applied to the propulsion system and airframe. Certification noise levels are predicted and compared with the NASA goal.

  8. An Analytical Assessment of NASA's N+1 Subsonic Fixed Wing Project Noise Goal

    NASA Technical Reports Server (NTRS)

    Berton, Jeffrey J.; Envia, Edmane; Burley, Casey L.

    2009-01-01

    The Subsonic Fixed Wing Project of NASA's Fundamental Aeronautics Program has adopted a noise reduction goal for new, subsonic, single-aisle, civil aircraft expected to replace current 737 and A320 airplanes. These so-called 'N+1' aircraft - designated in NASA vernacular as such since they will follow the current, in-service, 'N' airplanes - are hoped to achieve certification noise goal levels of 32 cumulative EPNdB under current Stage 4 noise regulations. A notional, N+1, single-aisle, twinjet transport with ultrahigh bypass ratio turbofan engines is analyzed in this study using NASA software and methods. Several advanced noise-reduction technologies are analytically applied to the propulsion system and airframe. Certification noise levels are predicted and compared with the NASA goal.

  9. Nonlinear interaction model of subsonic jet noise.

    PubMed

    Sandham, Neil D; Salgado, Adriana M

    2008-08-13

    Noise generation in a subsonic round jet is studied by a simplified model, in which nonlinear interactions of spatially evolving instability modes lead to the radiation of sound. The spatial mode evolution is computed using linear parabolized stability equations. Nonlinear interactions are found on a mode-by-mode basis and the sound radiation characteristics are determined by solution of the Lilley-Goldstein equation. Since mode interactions are computed explicitly, it is possible to find their relative importance for sound radiation. The method is applied to a single stream jet for which experimental data are available. The model gives Strouhal numbers of 0.45 for the most amplified waves in the jet and 0.19 for the dominant sound radiation. While in near field axisymmetric and the first azimuthal modes are both important, far-field sound is predominantly axisymmetric. These results are in close correspondence with experiment, suggesting that the simplified model is capturing at least some of the important mechanisms of subsonic jet noise.

  10. Transport in organic semiconductors in large electric fields: From thermal activation to field emission

    NASA Astrophysics Data System (ADS)

    Worne, J. H.; Anthony, J. E.; Natelson, D.

    2010-02-01

    Understanding charge transport in organic semiconductors in large electric fields is relevant to many applications. We present transport measurements in organic field-effect transistors based on poly(3-hexylthiophene) and 6,13-bis(triisopropyl-silylethynyl) (TIPS) pentacene with short channels, from room temperature down to 4.2 K. Near 300 K transport in both systems is well described by thermally assisted hopping with Poole-Frenkel-type enhancement of the mobility. At low temperatures and large gate voltages, transport in both materials becomes nearly temperature independent, crossing over into field-driven tunneling. These data, particularly in TIPS-pentacene, show that great caution must be exercised when considering more exotic (e.g., Tomonaga-Luttinger liquid) interpretations of transport.

  11. Counter-gradient heat transport by large-scale circulation in two-dimensional turbulent convection

    NASA Astrophysics Data System (ADS)

    Qiang, Wei; Cao, Hui; Li, Weimin; Zhang, Fansiqi

    2017-06-01

    We investigate numerically the counter-gradient heat transport in two-dimensional turbulent Rayleigh-Bénard convection, which derives its existence from the descending hot plumes and ascending cold plumes with the large-scale circulation. Both qualitative and quantitative evidence is presented for the Rayleigh numbers from 104 to 1011 and the Prandtl number 1.0 in a domain of aspect ratio 2 with periodic boundary conditions in the horizontal direction. The counter-gradient heat transport increases with Rayleigh numbers, and becomes comparable to the gradient heat transport. The gradient heat transport has a power law dependence on the Rayleigh number with scaling exponent 1/3, while a phase transition of the counter-gradient heat transport can be identified around the critical Rayleigh number 2×107 . The Reynolds numbers of the gradient and counter-gradient heat transports exhibit identical power law dependence on the Rayleigh numbers with scaling exponent 1/2. The gradient heat transport is partially compensated by the counter-gradient heat transport with increasing Rayleigh numbers, which attenuates the effects of the large-scale circulation on the global heat transfer especially for high Rayleigh numbers. We emphasize that the counter-gradient heat transport also exists in the three-dimensional turbulent Rayleigh-Bénard convection, although the plume and flow structures therein are quite different.

  12. Identification of large-scale hydraulic conductivity trends and the influence of trends on contaminant transport

    NASA Astrophysics Data System (ADS)

    Eggleston, Jack; Rojstaczer, Stuart

    1998-09-01

    We examine the identification of large-scale spatial trends in hydraulic conductivity and the influence of these trends on contaminant transport. Using three different trend identification methods, polynomial regression and Kaiman filtering, which fit smooth functions, and hydrofacies delineation, which constructs a geologic model, we try to identify the hydraulic conductivity patterns controlling solute transport in a heavily sampled heterogeneous aquifer on Columbus Air Force Base, Mississippi. Even with >2400 hydraulic conductivity measurements, unambiguous determination of large-scale trends is not possible. None of the estimated hydraulic conductivity trends gives transport simulations that reproduce the observed non-Gaussian transport behavior. Hydrofacies delineation and Kalman filtering give the best results. While the influence of the identified large-scale trends on advective transpo) hydraulic conductivity structures.

  13. Simulator study of flight characteristics of several large, dissimilar, cargo transport airplanes during approach and landing

    NASA Technical Reports Server (NTRS)

    Grantham, W. D.; Smith, P. M.; Deal, P. L.; Neely, W. R., Jr.

    1984-01-01

    A six-degree-of-freedom, ground based simulator study is conducted to evaluate the low-speed flight characteristics of four dissimilar cargo transport airplanes. These characteristics are compared with those of a large, present-day (reference) transport configuration similar to the Lockheed C-5A airplane. The four very large transport concepts evaluated consist of single-fuselage, twin-fuselage, triple-fuselage, and span-loader configurations. The primary piloting task is the approach and landing operation. The results of his study indicate that all four concepts evaluated have unsatisfactory longitudinal and lateral directional low speed flight characteristics and that considerable stability and control augmentation would be required to improve these characteristics (handling qualities) to a satisfactory level. Through the use of rate command/attitude hold augmentation in the pitch and roll axes, and the use of several turn-coordination features, the handling qualities of all four large transports simulated are improved appreciably.

  14. Effect of winglets on a first-generation jet transport wing. 1: Longitudinal aerodynamic characteristics of a semispan model at subsonic speeds. [in the Langley 8 ft transonic tunnel

    NASA Technical Reports Server (NTRS)

    Jacobs, P. F.; Flechner, S. G.; Montoya, L. C.

    1977-01-01

    The effects of winglets and a simple wing-tip extension on the aerodynamic forces and moments and the flow-field cross flow velocity vectors behind the wing tip of a first generation jet transport wing were investigated in the Langley 8-foot transonic pressure tunnel using a semi-span model. The test was conducted at Mach numbers of 0.30, 0.70, 0.75, 0.78, and 0.80. At a Mach number of 0.30, the configurations were tested with combinations of leading- and trailing-edge flaps.

  15. 14 CFR 135.365 - Large transport category airplanes: Reciprocating engine powered: Weight limitations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Large transport category airplanes: Reciprocating engine powered: Weight limitations. 135.365 Section 135.365 Aeronautics and Space FEDERAL AVIATION... PERSONS ON BOARD SUCH AIRCRAFT Airplane Performance Operating Limitations § 135.365 Large...

  16. 14 CFR 135.381 - Large transport category airplanes: Turbine engine powered: En route limitations: One engine...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Limitations § 135.381 Large transport category airplanes: Turbine engine powered: En route limitations: One engine inoperative. (a) No person operating a turbine engine powered large transport category airplane... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Large transport category airplanes: Turbine...

  17. 14 CFR 135.381 - Large transport category airplanes: Turbine engine powered: En route limitations: One engine...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Limitations § 135.381 Large transport category airplanes: Turbine engine powered: En route limitations: One engine inoperative. (a) No person operating a turbine engine powered large transport category airplane... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Large transport category airplanes: Turbine...

  18. 14 CFR 135.381 - Large transport category airplanes: Turbine engine powered: En route limitations: One engine...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Large transport category airplanes: Turbine... Limitations § 135.381 Large transport category airplanes: Turbine engine powered: En route limitations: One engine inoperative. (a) No person operating a turbine engine powered large transport category...

  19. 14 CFR 135.381 - Large transport category airplanes: Turbine engine powered: En route limitations: One engine...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Large transport category airplanes: Turbine... Limitations § 135.381 Large transport category airplanes: Turbine engine powered: En route limitations: One engine inoperative. (a) No person operating a turbine engine powered large transport category...

  20. 14 CFR 135.381 - Large transport category airplanes: Turbine engine powered: En route limitations: One engine...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Large transport category airplanes: Turbine... Limitations § 135.381 Large transport category airplanes: Turbine engine powered: En route limitations: One engine inoperative. (a) No person operating a turbine engine powered large transport category...

  1. 14 CFR 135.383 - Large transport category airplanes: Turbine engine powered: En route limitations: Two engines...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Large transport category airplanes: Turbine... Limitations § 135.383 Large transport category airplanes: Turbine engine powered: En route limitations: Two...). No person may operate a turbine engine powered large transport category airplane along an intended...

  2. 14 CFR 135.383 - Large transport category airplanes: Turbine engine powered: En route limitations: Two engines...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Large transport category airplanes: Turbine... Limitations § 135.383 Large transport category airplanes: Turbine engine powered: En route limitations: Two...). No person may operate a turbine engine powered large transport category airplane along an intended...

  3. 14 CFR 135.383 - Large transport category airplanes: Turbine engine powered: En route limitations: Two engines...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Large transport category airplanes: Turbine... Limitations § 135.383 Large transport category airplanes: Turbine engine powered: En route limitations: Two...). No person may operate a turbine engine powered large transport category airplane along an intended...

  4. 14 CFR 135.383 - Large transport category airplanes: Turbine engine powered: En route limitations: Two engines...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Large transport category airplanes: Turbine... Limitations § 135.383 Large transport category airplanes: Turbine engine powered: En route limitations: Two...). No person may operate a turbine engine powered large transport category airplane along an...

  5. 14 CFR 135.383 - Large transport category airplanes: Turbine engine powered: En route limitations: Two engines...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Large transport category airplanes: Turbine... Limitations § 135.383 Large transport category airplanes: Turbine engine powered: En route limitations: Two...). No person may operate a turbine engine powered large transport category airplane along an...

  6. Langley 14- by 22-foot subsonic tunnel test engineer's data acquisition and reduction manual

    NASA Technical Reports Server (NTRS)

    Quinto, P. Frank; Orie, Nettie M.

    1994-01-01

    The Langley 14- by 22-Foot Subsonic Tunnel is used to test a large variety of aircraft and nonaircraft models. To support these investigations, a data acquisition system has been developed that has both static and dynamic capabilities. The static data acquisition and reduction system is described; the hardware and software of this system are explained. The theory and equations used to reduce the data obtained in the wind tunnel are presented; the computer code is not included.

  7. Large-Scale V/STOL Experimental Investigations of an Ejector-Lift Fighter and a Twin Tilt-Nacelle Transport

    NASA Technical Reports Server (NTRS)

    Dudley, Michael R.

    2016-01-01

    In the 1980s NASA Aeronautics was actively involved in full-scale wind tunnel testing of promising VSTOL aircraft concepts. This presentation looks at two, a multi-role fighter and a subsonic tactical transport. Their strengths and weaknesses are discussed with some of the rationale that ultimately led to the selection of competing concepts for production, namely the V-22 Osprey and the F-35 Lightning. The E7-A STOVL multi-role fighter was the product of an aircraft development program in the late 1980s by NASA, the Defense Advanced Research Projects Agency (DARPA), the Canadian Department of Industry Science and Technology (DIST), and industry partners General Dynamics and Boeing Dehavilland. The program was conducted an in response to increasing US-UK interest in supersonic STOVL fighters. The objective was to design an aircraft that could replace most existing close air support-air combat fighters with a single aircraft that had some of the qualities of an air superiority fighter and the deployment flexibility of a VSTOL aircraft. The resulting E7-A concept was a delta-wing supersonic fighter that used a fuselage-mounted thrust augmenting ejector and a ventral deflecting jet nozzle for vertical lift. The Grumman Aircraft Company, the Navy, and NASA developed the Design-698 (D-698) subsonic tactical transport in response to the Navy's Type A VSTOL utility aircraft requirement. The objective was to develop a subsonic utility transport with the operational flexibility of a helicopter, but with greater speed and range. The D-698 employs two high-bypass turbofan engines mounted on a dumbbell that rotates through ninety degrees for vertical takeoff and cruise flight. Movable vanes positioned in the exhaust flow provide control in hover with the need for reaction control jets. The presentations concluding comments suggest that technology advances in the last thirty-years may justify the value of revisiting some of these concepts.

  8. The influence of large-scale motion on turbulent transport for confined coaxial jets

    NASA Technical Reports Server (NTRS)

    Brondum, D. C.; Bennett, J. C.

    1984-01-01

    The existence of large-scale coherent structures in turbulent shear flows has been well documented in the literature. The importance of these structures in flow entrainment, momentum transport and mass transport in the shear layer has been suggested by several researchers. Comparisons between existing models and experimental data for shear flow in confined coaxial jets reinforce the necessity of further investigation of the large scale structures. These comparisons show the greatest discrepancy between prediction and actual results in the developing flow region where the large scales exist. It was also observed that the momentum transport rate comparisons were very bad. Finally, Schetz has reviewed mixing flows and concluded that large-scale structures were essential aspects of future modeling efforts.

  9. Packaging, Transportation, and Disposal Logistics for Large Radioactively Contaminated Reactor Decommissioning Components

    SciTech Connect

    Lewis, Mark S.

    2008-01-15

    The packaging, transportation and disposal of large, retired reactor components from operating or decommissioning nuclear plants pose unique challenges from a technical as well as regulatory compliance standpoint. In addition to the routine considerations associated with any radioactive waste disposition activity, such as characterization, ALARA, and manifesting, the technical challenges for large radioactively contaminated components, such as access, segmentation, removal, packaging, rigging, lifting, mode of transportation, conveyance compatibility, and load securing require significant planning and execution. In addition, the current regulatory framework, domestically in Titles 49 and 10 and internationally in TS-R-1, does not lend itself to the transport of these large radioactively contaminated components, such as reactor vessels, steam generators, reactor pressure vessel heads, and pressurizers, without application for a special permit or arrangement. This paper addresses the methods of overcoming the technical and regulatory challenges. The challenges and disposition decisions do differ during decommissioning versus component replacement during an outage at an operating plant. During decommissioning, there is less concern about critical path for restart and more concern about volume reduction and waste minimization. Segmentation on-site is an available option during decommissioning, since labor and equipment will be readily available and decontamination activities are routine. The reactor building removal path is also of less concern and there are more rigging/lifting options available. Radionuclide assessment is necessary for transportation and disposal characterization. Characterization will dictate the packaging methodology, transportation mode, need for intermediate processing, and the disposal location or availability. Characterization will also assist in determining if the large component can be transported in full compliance with the transportation

  10. On the stability of subsonic thermal fronts

    SciTech Connect

    Ibanez S, Miguel H.; Shchekinov, Yuri; Bessega L, Maria C.

    2005-08-15

    The stability of subsonic thermal fronts against corrugation is analyzed and an exact dispersion relation is obtained taking into account the compressibility of the gas. For heat fronts, this dispersion equation has an unstable root ({omega}{sub ex}) corresponding to the Landau-Darrieus unstable mode ({omega}{sub 0}) modified by the compressional effects. In particular, the exact solution shows a conspicuous maximum very close to the value of the intake Mach number M{sub 1} at which a Chapman-Jouguet deflagration wave behind the heat front is formed. Cooling fronts are stable for corrugation-like disturbances. A maximum damping as well as a maximum in the frequency occur at a value of M{sub 1} depending on the value of the normalized cooling q.

  11. Subsonic Glideback Rocket Demonstrator Flight Testing

    NASA Technical Reports Server (NTRS)

    DeTurris, Dianne J.; Foster, Trevor J.; Barthel, Paul E.; Macy, Daniel J.; Droney, Christopher K.; Talay, Theodore A. (Technical Monitor)

    2001-01-01

    For the past two years, Cal Poly's rocket program has been aggressively exploring the concept of remotely controlled, fixed wing, flyable rocket boosters. This program, embodied by a group of student engineers known as Cal Poly Space Systems, has successfully demonstrated the idea of a rocket design that incorporates a vertical launch pattern followed by a horizontal return flight and landing. Though the design is meant for supersonic flight, CPSS demonstrators are deployed at a subsonic speed. Many steps have been taken by the club that allowed the evolution of the StarBooster prototype to reach its current size: a ten-foot tall, one-foot diameter, composite material rocket. Progress is currently being made that involves multiple boosters along with a second stage, third rocket.

  12. Subsonic Gas Flow Past A Wing Profile

    NASA Technical Reports Server (NTRS)

    Christianovich, S. A.; Yuriev, I. M.

    1950-01-01

    The use of the linearized equations of Chaplygin to calculate the subsonic flow of a gas permits solving the problem of the flow about a wing profile for absence and presence of circulation. The solution is obtained in a practical convenient form that permits finding all the required magnitudes for the gas flow (lift, lift moment velocity distribution over the profile, and critical Mach number). This solution is not expressed in simple closed form; for a certain simplifying assumption, however, the equations of Chaplygin can be reduced to equations with constant coefficients, and solutions are obtained by using only the mathematical apparatus of the theory of functions of a complex variable. The method for simplifying the equations was pointed out by Chaplygin himself. These applied similar equations to the solution of the flow problem and obtained a solution for the case of the absence of circulation.

  13. Rectangular subsonic jet flow field measurements

    NASA Technical Reports Server (NTRS)

    Morrison, Gerald L.; Swan, David H.

    1989-01-01

    Flow field measurements are presented of 3 subsonic rectangular cold air jets. The 3 cases presented had aspect ratios of 1 x 2, 1 x 4 at a Mach number of 0.09 and an aspect ratio of 1 x 2 at a Mach number of 0.9. All measurements were made using a 3-D laser Doppler anemoneter system. The presented data includes the mean velocity vector, all Reynolds stress tensor components, turbulent kinetic energy and velocity correlation coefficients. The data is presented in tabular and graphical form. No analysis of the measured data or comparison to other published data is made. All tabular data are available in ASCII format on MS-DOS compatible disks.

  14. Subsonic flight test evaluation of a performance seeking control algorithm on an F-15 airplane

    NASA Technical Reports Server (NTRS)

    Gilyard, Glenn B.; Orme, John S.

    1992-01-01

    The subsonic flight test evaluation phase of the NASA F-15 (powered by F 100 engines) performance seeking control program was completed for single-engine operation at part- and military-power settings. The subsonic performance seeking control algorithm optimizes the quasi-steady-state performance of the propulsion system for three modes of operation. The minimum fuel flow mode minimizes fuel consumption. The minimum thrust mode maximizes thrust at military power. Decreases in thrust-specific fuel consumption of 1 to 2 percent were measured in the minimum fuel flow mode; these fuel savings are significant, especially for supersonic cruise aircraft. Decreases of up to approximately 100 degree R in fan turbine inlet temperature were measured in the minimum temperature mode. Temperature reductions of this magnitude would more than double turbine life if inlet temperature was the only life factor. Measured thrust increases of up to approximately 15 percent in the maximum thrust mode cause substantial increases in aircraft acceleration. The system dynamics of the closed-loop algorithm operation were good. The subsonic flight phase has validated the performance seeking control technology, which can significantly benefit the next generation of fighter and transport aircraft.

  15. Large-scale isolation of human erythrocyte Ca2+-transport ATPase.

    PubMed Central

    Gietzen, K; Kolandt, J

    1982-01-01

    A rapid procedure for preparing large quantities of purified erythrocyte Ca2+-transport ATPase is presented. The method involves: (1) fast preparation of calmodulin-deficient, essentially haemoglobin-free, erythrocyte membranes by molecular filtration using Pellicon filters; (2) solubilization of membrane proteins by deoxycholate; and (3) a batch procedure using calmodulin-Sepharose 4B gel for purification of Ca2+-transport ATPase. Images Fig. 1. PMID:6217813

  16. Variation in material transport and water chemistry along a large ephemeral river in the Namib Desert

    USGS Publications Warehouse

    Jacobson, P.J.; Jacobson, K.M.; Angermeier, P.L.; Cherry, D.S.

    2000-01-01

    1. The chemical characteristics of floodwaters in ephemeral rivers are little known, particularly with regard to their organic loads. These rivers typically exhibit a pronounced downstream hydrological decay but few studies have documented its effect on chemical characteristics and material transport. To develop a better understanding of the dynamics of floods and associated material transport in large ephemeral rivers, floods of the ephemeral Kuiseb River in south-western Africa were tracked and repeatedly sampled at multiple points along the river's lower 220 km. 2. We quantified the composition and transport of solute and sediment loads in relation to longitudinal hydrological patterns associated with downstream hydrological decay. Source and sink areas for transported materials were identified, and the composition and transport dynamics of the organic matter load were compared to those described from more mesic systems. 3. Concentrations of sediments and solutes transported by floods in the Kuiseb River tended to increase downstream in association with pronounced hydrological decay. The contribution of particulate organic matter to total organic load is among the highest recorded, despite our observation of unusually high levels of dissolved organic matter. Hydrological decay resulted in deposition of all transported material within the lower Kuiseb River, with no discharge of water or materials to the Atlantic Ocean. 4. Our results suggest that longitudinal variation in surface flow and associated patterns of material transport renders the lower Kuiseb River a sink for materials transported from upstream. The downstream transport and deposition of large amounts of labile organic matter provides an important carbon supplement to heterotrophic communities within the river's lower reaches.

  17. Morphological response of a large-scale coastal blowout to a strong magnitude transport event

    NASA Astrophysics Data System (ADS)

    Delgado-Fernandez, Irene; Jackson, Derek; Smith, Alexander; Smyth, Thomas

    2017-04-01

    Large-scale blowouts are fundamental features of many coastal dune fields in temperate areas around the world. These distinctive erosional (mostly unvegetated) landform features are often characterised by a significant depression area and a connected depositional lobe at their downwind edges. These areas also provide important transport corridors to inland parts of the dune system and can provide ideal habitats for specialist flora and fauna as well as helping to enhance landscape diversity. The actual morphology and shape/size of blowouts can significantly modify the overlying atmospheric boundary layer of the wind, influencing wind flow steering and intensity within the blowout, and ultimately aeolian sediment transport. While investigations of morphological changes within blowouts have largely focused on the medium (months) to long (annual/decadal) temporal scale, studies of aeolian transport dynamics within blowouts have predominantly focused on the short-term (event) scale. Work on wind-transport processes in blowouts is still relatively rare, with ad-hoc studies providing only limited information on airflow and aeolian transport. Large-scale blowouts are characterised by elongated basins that can reach hundreds of meters, potentially resulting in airflow and transport dynamics that are very different from their smaller scale counterparts. This research focuses on a short-term, strong wind event measured at the Devil's Hole blowout (Sefton dunes, NW England), a large-scale blowout feature approximately 300 m in length and 100 m in width. In situ measurements of airflow and aeolian transport were collected during a short-term experiment on the 22nd October 2015. A total of twenty three, 3D ultrasonic anemometers, sand traps, and wenglor sensors were deployed in a spatial grid covering the distal end of the basin, walls, and depositional lobe. Terrestrial laser scanning (TLS) was used to quantify morphological changes within the blowout before and after the

  18. Large-Scale Transportation Network Congestion Evolution Prediction Using Deep Learning Theory

    PubMed Central

    Ma, Xiaolei; Yu, Haiyang; Wang, Yunpeng; Wang, Yinhai

    2015-01-01

    Understanding how congestion at one location can cause ripples throughout large-scale transportation network is vital for transportation researchers and practitioners to pinpoint traffic bottlenecks for congestion mitigation. Traditional studies rely on either mathematical equations or simulation techniques to model traffic congestion dynamics. However, most of the approaches have limitations, largely due to unrealistic assumptions and cumbersome parameter calibration process. With the development of Intelligent Transportation Systems (ITS) and Internet of Things (IoT), transportation data become more and more ubiquitous. This triggers a series of data-driven research to investigate transportation phenomena. Among them, deep learning theory is considered one of the most promising techniques to tackle tremendous high-dimensional data. This study attempts to extend deep learning theory into large-scale transportation network analysis. A deep Restricted Boltzmann Machine and Recurrent Neural Network architecture is utilized to model and predict traffic congestion evolution based on Global Positioning System (GPS) data from taxi. A numerical study in Ningbo, China is conducted to validate the effectiveness and efficiency of the proposed method. Results show that the prediction accuracy can achieve as high as 88% within less than 6 minutes when the model is implemented in a Graphic Processing Unit (GPU)-based parallel computing environment. The predicted congestion evolution patterns can be visualized temporally and spatially through a map-based platform to identify the vulnerable links for proactive congestion mitigation. PMID:25780910

  19. Large-scale transportation network congestion evolution prediction using deep learning theory.

    PubMed

    Ma, Xiaolei; Yu, Haiyang; Wang, Yunpeng; Wang, Yinhai

    2015-01-01

    Understanding how congestion at one location can cause ripples throughout large-scale transportation network is vital for transportation researchers and practitioners to pinpoint traffic bottlenecks for congestion mitigation. Traditional studies rely on either mathematical equations or simulation techniques to model traffic congestion dynamics. However, most of the approaches have limitations, largely due to unrealistic assumptions and cumbersome parameter calibration process. With the development of Intelligent Transportation Systems (ITS) and Internet of Things (IoT), transportation data become more and more ubiquitous. This triggers a series of data-driven research to investigate transportation phenomena. Among them, deep learning theory is considered one of the most promising techniques to tackle tremendous high-dimensional data. This study attempts to extend deep learning theory into large-scale transportation network analysis. A deep Restricted Boltzmann Machine and Recurrent Neural Network architecture is utilized to model and predict traffic congestion evolution based on Global Positioning System (GPS) data from taxi. A numerical study in Ningbo, China is conducted to validate the effectiveness and efficiency of the proposed method. Results show that the prediction accuracy can achieve as high as 88% within less than 6 minutes when the model is implemented in a Graphic Processing Unit (GPU)-based parallel computing environment. The predicted congestion evolution patterns can be visualized temporally and spatially through a map-based platform to identify the vulnerable links for proactive congestion mitigation.

  20. Supersonic Jet Exhaust Noise at High Subsonic Flight Speed

    NASA Technical Reports Server (NTRS)

    Norum, Thomas D.; Garber, Donald P.; Golub, Robert A.; Santa Maria, Odilyn L.; Orme, John S.

    2004-01-01

    An empirical model to predict the effects of flight on the noise from a supersonic transport is developed. This model is based on an analysis of the exhaust jet noise from high subsonic flights of the F-15 ACTIVE Aircraft. Acoustic comparisons previously attainable only in a wind tunnel were accomplished through the control of both flight operations and exhaust nozzle exit diameter. Independent parametric variations of both flight and exhaust jet Mach numbers at given supersonic nozzle pressure ratios enabled excellent correlations to be made for both jet broadband shock noise and jet mixing noise at flight speeds up to Mach 0.8. Shock noise correlated with flight speed and emission angle through a Doppler factor exponent of about 2.6. Mixing noise at all downstream angles was found to correlate well with a jet relative velocity exponent of about 7.3, with deviations from this behavior only at supersonic eddy convection speeds and at very high flight Mach numbers. The acoustic database from the flight test is also provided.

  1. An Overview of NASA's Subsonic Research Aircraft Testbed (SCRAT)

    NASA Technical Reports Server (NTRS)

    Baumann, Ethan; Hernandez, Joe; Ruhf, John C.

    2013-01-01

    National Aeronautics and Space Administration Dryden Flight Research Center acquired a Gulfstream III (GIII) aircraft to serve as a testbed for aeronautics flight research experiments. The aircraft is referred to as SCRAT, which stands for SubsoniC Research Aircraft Testbed. The aircraft's mission is to perform aeronautics research; more specifically raising the Technology Readiness Level (TRL) of advanced technologies through flight demonstrations and gathering high-quality research data suitable for verifying the technologies, and validating design and analysis tools. The SCRAT has the ability to conduct a range of flight research experiments throughout a transport class aircraft's flight envelope. Experiments ranging from flight-testing of a new aircraft system or sensor to those requiring structural and aerodynamic modifications to the aircraft can be accomplished. The aircraft has been modified to include an instrumentation system and sensors necessary to conduct flight research experiments along with a telemetry capability. An instrumentation power distribution system was installed to accommodate the instrumentation system and future experiments. An engineering simulation of the SCRAT has been developed to aid in integrating research experiments. A series of baseline aircraft characterization flights has been flown that gathered flight data to aid in developing and integrating future research experiments. This paper describes the SCRAT's research systems and capabilities.

  2. 1. VIEW SOUTHWEST OF SUBSONIC WIND TUNNEL BUILDING AND TRANSONIC ...

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

    1. VIEW SOUTHWEST OF SUBSONIC WIND TUNNEL BUILDING AND TRANSONIC WIND TUNNEL BUILDING - Naval Surface Warfare Center, Bounded by Clara Barton Parkway & McArthur Boulevard, Silver Spring, Montgomery County, MD

  3. 3. VIEW SOUTHEAST OF TRANSONIC WIND TUNNEL BUILDING TO SUBSONIC ...

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

    3. VIEW SOUTHEAST OF TRANSONIC WIND TUNNEL BUILDING TO SUBSONIC WIND TUNNEL BUILDING - Naval Surface Warfare Center, Bounded by Clara Barton Parkway & McArthur Boulevard, Silver Spring, Montgomery County, MD

  4. 7. VIEW NORTHWEST OF SUBSONIC WIND TUNNEL BUILDING TO TRANSONIC ...

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

    7. VIEW NORTHWEST OF SUBSONIC WIND TUNNEL BUILDING TO TRANSONIC WIND TUNNEL BUILDING - Naval Surface Warfare Center, Bounded by Clara Barton Parkway & McArthur Boulevard, Silver Spring, Montgomery County, MD

  5. 5. VIEW NORTHWEST OF SUBSONIC WIND TUNNEL BUILDING TO TRANSONIC ...

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

    5. VIEW NORTHWEST OF SUBSONIC WIND TUNNEL BUILDING TO TRANSONIC WIND TUNNEL BUILDING - Naval Surface Warfare Center, Bounded by Clara Barton Parkway & McArthur Boulevard, Silver Spring, Montgomery County, MD

  6. The role of freestream turbulence scale in subsonic flow separation

    NASA Technical Reports Server (NTRS)

    Potter, J. L.; Seebaugh, W. R.; Barnett, R. J.; Gokhale, R. B.

    1984-01-01

    The ojective of this work is the clarification of the role of freestream turbulence scale in determining the location of boundary layer separation. An airfoil in subsonic wind tunnel flow is the specific case studied. Hot-film and hot-wire anemometry, liquid-film visualization and pressure measurements are the principal diagnostic techniques in use. The Vanderbilt University subsonic wind tunnel is the flow facility being used.

  7. Planar microdevices enhance transport of large molecular weight molecules across retinal pigment epithelial cells.

    PubMed

    Wade, Jennifer S; Desai, Tejal A

    2014-08-01

    Large molecular weight drug delivery to the posterior eye is challenging due to cellular barriers that hinder drug transport. Understanding how to enhance transport across the retinal barrier is important for the design of new drug delivery systems. A novel mechanism to enhance drug transport is the use of geometric properties, which has not been extensively explored in the retina. Planar SU-8/Poly(ethyleneglycol)dimethacrylate microdevices were constructed using photolithography to deliver FITC dextran across an in vitro retinal model. The model consists of retinal pigment epithelial (RPE) cells grown to confluence on transwell inserts, which provides an environment to investigate the influence of geometry on paracellular and transcellular delivery of encapsulated large molecules. Planar microdevices enhanced transport of large molecular weight dextrans across different models of RPE in a size dependent fashion. Increased drug permeation across the RPE was observed with the addition of microdevices as compared to a traditional bolus of FITC dextran. This phenomena was initiated by a non-toxic interaction between the microdevices and the retinal tight junction proteins. Suggesting that increased drug transport occurs via a paracellular pathway. These experiments provide evidence to support the future use of planar unidirectional microdevices for delivery of biologics in ocular applications.

  8. Planar Microdevices Enhance Transport of Large Molecular Weight Molecules Across Retinal Pigment Epithelial Cells

    PubMed Central

    Wade, Jennifer S.; Desai, Tejal A.

    2014-01-01

    Large molecular weight drug delivery to the posterior eye is challenging due to cellular barriers that hinder drug transport. Understanding how to enhance transport across the retinal barrier is important for the design of new drug delivery systems. A novel mechanism to enhance drug transport is the use of geometric properties, which has not been extensively explored in the retina. Planar SU-8/ Poly(ethyleneglycol)dimethacrylate microdevices were constructed using photolithography to deliver FITC dextran across an in vitro retinal model. The model consists of retinal pigment epithelial (RPE) cells grown to confluence on transwell inserts, which provides an environment to investigate the influence of geometry on paracellular and transcellular delivery of encapsulated large molecules. Planar microdevices enhanced transport of large molecular weight dextrans across different models of RPE in a size dependent fashion. Increased drug permeation across the RPE was observed with the addition of microdevices as compared to a traditional bolus of FITC dextran. This phenomena was initiated by a non-toxic interaction between the microdevices and the retinal tight junction proteins. Suggesting that increased drug transport occurs via a paracellular pathway. These experiments provide evidence to support the future use of planar unidirectional microdevices for delivery of biologics in ocular applications. PMID:24789225

  9. Turbulence and Transport in Multi-Ion Species Plasmas in the Large Plasma Device

    NASA Astrophysics Data System (ADS)

    Robertson, Jeffrey

    2016-10-01

    Understanding of turbulence and transport in multi-ion-species plasmas is important for establishing predictive capability for burning tokamak plasmas with comparable densities of D and T. Fundamental modifications to drift-wave instabilities and resulting turbulence are expected from theoretical studies, including new instabilities driven by dissimilar ion density gradients. Even in pure ion species plasmas, transport mysteries remain regarding dependence on ion mass such as the isotope scaling of turbulent transport. Recently, experiments have been performed on the Large Plasma Device at UCLA in which mixed Hydrogen-Helium plasmas were created and the relative concentration was varied systematically. The properties of edge turbulence and transport rates were documented and initial results will be presented. Experimental results are will also be compared to linear drift-wave instability theory in plasmas with multiple ion species.

  10. Quasispherical subsonic accretion in X-ray pulsars

    NASA Astrophysics Data System (ADS)

    Shakura, Nikolai I.; Postnov, Konstantin A.; Kochetkova, A. Yu; Hjalmarsdotter, L.

    2013-04-01

    A theoretical model is considered for quasispherical subsonic accretion onto slowly rotating magnetized neutron stars. In this regime, the accreting matter settles down subsonically onto the rotating magnetosphere, forming an extended quasistatic shell. Angular momentum transfer in the shell occurs via large-scale convective motions resulting, for observed pulsars, in an almost iso-angular-momentum \\omega \\sim 1/R^2 rotation law inside the shell. The accretion rate through the shell is determined by the ability of the plasma to enter the magnetosphere due to Rayleigh-Taylor instabilities, with allowance for cooling. A settling accretion regime is possible for moderate accretion rates \\dot M \\lesssim \\dot M_* \\simeq 4\\times 10^{16} g s ^{-1}. At higher accretion rates, a free-fall gap above the neutron star magnetosphere appears due to rapid Compton cooling, and the accretion becomes highly nonstationary. Observations of spin-up/spin-down rates of quasispherically wind accreting equilibrium X-ray pulsars with known orbital periods (e.g., GX 301-2 and Vela X-1) enable us to determine the main dimensionless parameters of the model, as well as to estimate surface magnetic field of the neutron star. For equilibrium pulsars, the independent measurements of the neutron star magnetic field allow for an estimate of the stellar wind velocity of the optical companion without using complicated spectroscopic measurements. For nonequilibrium pulsars, a maximum value is shown to exist for the spin-down rate of the accreting neutron star. From observations of the spin-down rate and the X-ray luminosity in such pulsars (e.g., GX 1+4, SXP 1062, and 4U 2206+54), a lower limit can be put on the neutron star magnetic field, which in all cases turns out to be close to the standard value and which agrees with cyclotron line measurements. Furthermore, both explains the spin-up/spin-down of the pulsar frequency on large time-scales and also accounts for the irregular short

  11. SUBSONIC WIND TUNNEL PERFORMANCE ANALYSIS SOFTWARE

    NASA Technical Reports Server (NTRS)

    Eckert, W. T.

    1994-01-01

    This program was developed as an aid in the design and analysis of subsonic wind tunnels. It brings together and refines previously scattered and over-simplified techniques used for the design and loss prediction of the components of subsonic wind tunnels. It implements a system of equations for determining the total pressure losses and provides general guidelines for the design of diffusers, contractions, corners and the inlets and exits of non-return tunnels. The algorithms used in the program are applicable to compressible flow through most closed- or open-throated, single-, double- or non-return wind tunnels or ducts. A comparison between calculated performance and that actually achieved by several existing facilities produced generally good agreement. Any system through which air is flowing which involves turns, fans, contractions etc. (e.g., an HVAC system) may benefit from analysis using this software. This program is an update of ARC-11138 which includes PC compatibility and an improved user interface. The method of loss analysis used by the program is a synthesis of theoretical and empirical techniques. Generally, the algorithms used are those which have been substantiated by experimental test. The basic flow-state parameters used by the program are determined from input information about the reference control section and the test section. These parameters were derived from standard relationships for compressible flow. The local flow conditions, including Mach number, Reynolds number and friction coefficient are determined for each end of each component or section. The loss in total pressure caused by each section is calculated in a form non-dimensionalized by local dynamic pressure. The individual losses are based on the nature of the section, local flow conditions and input geometry and parameter information. The loss forms for typical wind tunnel sections considered by the program include: constant area ducts, open throat ducts, contractions, constant

  12. SUBSONIC WIND TUNNEL PERFORMANCE ANALYSIS SOFTWARE

    NASA Technical Reports Server (NTRS)

    Eckert, W. T.

    1994-01-01

    This program was developed as an aid in the design and analysis of subsonic wind tunnels. It brings together and refines previously scattered and over-simplified techniques used for the design and loss prediction of the components of subsonic wind tunnels. It implements a system of equations for determining the total pressure losses and provides general guidelines for the design of diffusers, contractions, corners and the inlets and exits of non-return tunnels. The algorithms used in the program are applicable to compressible flow through most closed- or open-throated, single-, double- or non-return wind tunnels or ducts. A comparison between calculated performance and that actually achieved by several existing facilities produced generally good agreement. Any system through which air is flowing which involves turns, fans, contractions etc. (e.g., an HVAC system) may benefit from analysis using this software. This program is an update of ARC-11138 which includes PC compatibility and an improved user interface. The method of loss analysis used by the program is a synthesis of theoretical and empirical techniques. Generally, the algorithms used are those which have been substantiated by experimental test. The basic flow-state parameters used by the program are determined from input information about the reference control section and the test section. These parameters were derived from standard relationships for compressible flow. The local flow conditions, including Mach number, Reynolds number and friction coefficient are determined for each end of each component or section. The loss in total pressure caused by each section is calculated in a form non-dimensionalized by local dynamic pressure. The individual losses are based on the nature of the section, local flow conditions and input geometry and parameter information. The loss forms for typical wind tunnel sections considered by the program include: constant area ducts, open throat ducts, contractions, constant

  13. Subsonic streamers in water: initiation, propagation and morphology

    NASA Astrophysics Data System (ADS)

    Li, X. D.; Liu, Y.; Zhou, G. Y.; Liu, S. W.; Li, Z. Y.; Lin, F. C.

    2017-06-01

    In this paper, we focus on the development and morphology of underwater subsonic streamers in a pin-plane electrode configuration. The processes of initiation, propagation and branching of underwater subsonic streamers are studied in detail, and the effects of applied voltage amplitude and polarity are discussed. The results show a similar initiation process for both polarities including the formation of a low-density shadowed region, an initial bubble and streamers. Joule heating is thought to be the dominant intrinsic dynamic in the initiation process. There is a distinct difference in the propagation mode and the morphology between positive and negative subsonic streamers. Positive subsonic streamers develop in the form of a bubble cluster with a constant low speed of 20-80 m s-1, but the development mode transition from bubble cluster to secondary streamer occurs at the final stage of streamer propagation. On the other hand, negative subsonic streamers develop in the form of tree-like structures with a thinner root and propagate faster at a speed of 100-370 m s-1, and the propagation velocity increases significantly near the final breakdowns. A specific phenomenon has been observed in which the breakdown voltage of positive polarity can be higher than that of negative polarity in micro-second underwater discharge. The above results indicate that the polarity effect of subsonic streamers is quite different from that of the supersonic streamers.

  14. The Effect of Yaw Coupling in Turning Maneuvers of Large Transport Aircraft

    NASA Technical Reports Server (NTRS)

    McNeill, Walter E.; Innis, Robert C.

    1965-01-01

    A study has been made, using a piloted moving simulator, of the effects of the yaw-coupling parameters N(sub p) and N(sub delta(sub a) on the lateral-directional handling qualities of a large transport airplane at landing-approach airspeed. It is shown that the desirable combinations of these parameters tend to be more proverse when compared with values typical of current aircraft. Results of flight tests in a large variable-stability jet transport showed trends which were similar to those of the simulator data. Areas of minor disagreement, which were traced to differences in airplane geometry, indicate that pilot consciousness of side acceleration forces can be an important factor in handling qualities of future long-nosed transport aircraft.

  15. Large-voltage behavior of charge transport characteristics in nanosystems with weak electron–vibration coupling

    PubMed Central

    Belzig, Wolfgang

    2015-01-01

    Summary We study analytically the Full Counting Statistics of the charge transport through a nanosystem consisting of a few electronic levels weakly coupled to a discrete vibrational mode. In the limit of large transport voltage bias the cumulant generating function can be evaluated explicitly based solely on the intuitive physical arguments and classical master equation description of the vibration mode. We find that for the undamped vibrational modes mutual dynamical interplay between electronic and vibronic degrees of freedom leads to strongly nonlinear (in voltage) transport characteristics of the nanosystem. In particular, we find that for large voltages the k-th cumulant of the current grows as V 2k to be contrasted with the linear dependence in case of more strongly externally damped and thus thermalized vibrational modes. PMID:26425436

  16. 14 CFR 135.379 - Large transport category airplanes: Turbine engine powered: Takeoff limitations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... engine powered: Takeoff limitations. 135.379 Section 135.379 Aeronautics and Space FEDERAL AVIATION... category airplanes: Turbine engine powered: Takeoff limitations. (a) No person operating a turbine engine... existing at take- off. (b) No person operating a turbine engine powered large transport category airplane...

  17. 14 CFR 135.379 - Large transport category airplanes: Turbine engine powered: Takeoff limitations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... engine powered: Takeoff limitations. 135.379 Section 135.379 Aeronautics and Space FEDERAL AVIATION... category airplanes: Turbine engine powered: Takeoff limitations. (a) No person operating a turbine engine... existing at take- off. (b) No person operating a turbine engine powered large transport category airplane...

  18. Distributed model of hydrological and sediment transport processes in large river basins in Southeast Asia

    NASA Astrophysics Data System (ADS)

    Zuliziana, S.; Tanuma, K.; Yoshimura, C.; Saavedra, O. C.

    2015-07-01

    Soil erosion and sediment transport have been modeled at several spatial and temporal scales, yet few models have been reported for large river basins (e.g., drainage areas > 100 000 km2). In this study, we propose a process-based distributed model for assessment of sediment transport at a large basin scale. A distributed hydrological model was coupled with a process-based distributed sediment transport model describing soil erosion and sedimentary processes at hillslope units and channels. The model was tested on two large river basins: the Chao Phraya River Basin (drainage area: 160 000 km2) and the Mekong River Basin (795 000 km2). The simulation over 10 years showed good agreement with the observed suspended sediment load in both basins. The average Nash-Sutcliffe efficiency (NSE) and average correlation coefficient (r) between the simulated and observed suspended sediment loads were 0.62 and 0.61, respectively, in the Chao Phraya River Basin except the lowland section. In the Mekong River Basin, the overall average NSE and r were 0.60 and 0.78, respectively. Sensitivity analysis indicated that suspended sediment load is sensitive to detachability by raindrop (k) in the Chao Phraya River Basin and to soil detachability over land (Kf) in the Mekong River Basin. Overall, the results suggest that the present model can be used to understand and simulate erosion and sediment transport in large river basins.

  19. An assembly model for simulation of large-scale ground water flow and transport.

    PubMed

    Huang, Junqi; Christ, John A; Goltz, Mark N

    2008-01-01

    When managing large-scale ground water contamination problems, it is often necessary to model flow and transport using finely discretized domains--for instance (1) to simulate flow and transport near a contamination source area or in the area where a remediation technology is being implemented; (2) to account for small-scale heterogeneities; (3) to represent ground water-surface water interactions; or (4) some combination of these scenarios. A model with a large domain and fine-grid resolution will need extensive computing resources. In this work, a domain decomposition-based assembly model implemented in a parallel computing environment is developed, which will allow efficient simulation of large-scale ground water flow and transport problems using domain-wide grid refinement. The method employs common ground water flow (MODFLOW) and transport (RT3D) simulators, enabling the solution of almost all commonly encountered ground water flow and transport problems. The basic approach partitions a large model domain into any number of subdomains. Parallel processors are used to solve the model equations within each subdomain. Schwarz iteration is applied to match the flow solution at the subdomain boundaries. For the transport model, an extended numerical array is implemented to permit the exchange of dispersive and advective flux information across subdomain boundaries. The model is verified using a conventional single-domain model. Model simulations demonstrate that the proposed model operated in a parallel computing environment can result in considerable savings in computer run times (between 50% and 80%) compared with conventional modeling approaches and may be used to simulate grid discretizations that were formerly intractable.

  20. Large collective motions regulate the functional properties of glutamate transporter trimers

    PubMed Central

    Jiang, Jie; Shrivastava, Indira H.; Watts, Spencer D.; Bahar, Ivet; Amara, Susan G.

    2011-01-01

    Glutamate transporters clear synaptically released glutamate to maintain precise communication between neurons and limit glutamate neurotoxicity. Although much progress has been made on the topology, structure, and function of these carriers, few studies have addressed large-scale structural motions collectively associated with substrate transport. Here we show that a series of single cysteine substitutions in the helical hairpin HP2 of excitatory amino acid transporter 1 form intersubunit disulfide cross-links within the trimer. After cross-linking, substrate uptake, but not substrate-activated anion conductance, is completely inhibited in these mutants. These disulfide bridges link residue pairs > 40 Å apart in the outward-facing crystal structure, and can be explained by concerted subunit movements predicted by the anisotropic network model (ANM). The existence of these global motions is further supported by the observation that single cysteine substitutions at the extracellular part of the transmembrane domain 8 can also be cross-linked by copper phenanthroline as predicted by the ANM. Interestingly, the transport domain in the un-cross-linked subunit of the trimer assumes an inward-facing orientation, suggesting that individual subunits potentially undergo separate transitions between outward- and inward-facing forms, rather than an all-or-none transition of the three subunits, a mechanism also supported by ANM-predicted intrinsic dynamics. These results shed light on how large collective motions contribute to the functional dynamics of glutamate transporters. PMID:21876140

  1. SHARP: Subsonic High Altitude Research Platform

    NASA Technical Reports Server (NTRS)

    Beals, Todd; Burton, Craig; Cabatan, Aileen; Hermano, Christine; Jones, Tom; Lee, Susan; Radloff, Brian

    1991-01-01

    The Universities Space Research Association is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to satisfy four mission profiles. Mission one is a polar mission that ranges from Chile to the South Pole and back to Chile, a total range of 6000 n.mi. at 100,000 ft with a 2500 lb payload. The second mission is also a polar mission, with an altitude of 70,000 ft and an increased payload of 4000 lbs. For the third mission, the aircraft will takeoff at NASA Ames, cruise at 100,000 ft carrying a 2500 lb payload, and land at Puerto Montt, Chile. The final mission requires the aircraft to take off at NASA Ames, cruise at 100,000 ft with a 1000 lb payload, make an excursion to 120,000 ft, and land at Howard AFB, Panama. Three missions require that a subsonic Mach number be maintained due to constraints imposed by the air sampling equipment. The aircraft need not be manned for all four missions. Three aircraft configurations have been determined to be the most suitable for meeting the above requirements. In the event that a requirement cannot be obtained within the given constraints, recommendations for proposal modifications are given.

  2. The Cylinder and Semicylinder in Subsonic Flow

    NASA Technical Reports Server (NTRS)

    Bingham, Harry J.; Weimer, David K..; Griffith, Wayland

    1952-01-01

    In studying the diffraction of shock waves around various two-dimensional obstacles we have observed that flow separation and the formation of vortices contributes in an important way to transient loading of the obstacle. The cases of a cylinder and semicylinder are especially interesting because the breakaway point is not clearly defined as it is for objects having sharp corners. Accordingly a number of experiments have been made in the shock tube to observe the influence of Reynolds number and Mach number on the transient flow patterns about a cylinder and about a semicylinder mounted on a smooth plane. Some differences might be anticipated since the plane would impose a symmetry on the flow and produce a viscous boundary layer for which there is no counterpart with the cylinder. In the course of these experiments it was noted that a condition of steady subsonic flow about both the cylinder and semicylinder was approached. Thus a comparison with von Karrnan's theoretical calculation of the drag on a cylinder, from certain characteristics of its wake or "vortex street", was undertaken.

  3. Advanced Subsonic Airplane Design and Economic Studies

    NASA Technical Reports Server (NTRS)

    Liebeck, Robert H.; Andrastek, Donald A.; Chau, Johnny; Girvin, Raquel; Lyon, Roger; Rawdon, Blaine K.; Scott, Paul W.; Wright, Robert A.

    1995-01-01

    A study was made to examine the effect of advanced technology engines on the performance of subsonic airplanes and provide a vision of the potential which these advanced engines offered. The year 2005 was selected as the entry-into-service (EIS) date for engine/airframe combination. A set of four airplane classes (passenger and design range combinations) that were envisioned to span the needs for the 2005 EIS period were defined. The airframes for all classes were designed and sized using 2005 EIS advanced technology. Two airplanes were designed and sized for each class: one using current technology (1995) engines to provide a baseline, and one using advanced technology (2005) engines. The resulting engine/airframe combinations were compared and evaluated on the basis on sensitivity to basic engine performance parameters (e.g. SFC and engine weight) as well as DOC+I. The advanced technology engines provided significant reductions in fuel burn, weight, and wing area. Average values were as follows: reduction in fuel burn = 18%, reduction in wing area = 7%, and reduction in TOGW = 9%. Average DOC+I reduction was 3.5% using the pricing model based on payload-range index and 5% using the pricing model based on airframe weight. Noise and emissions were not considered.

  4. Subsonic-transonic stall flutter study

    NASA Technical Reports Server (NTRS)

    Stardter, H.

    1979-01-01

    The objective of the Subsonic/Transonic Stall Flutter Program was to obtain detailed measurements of both the steady and unsteady flow field surrounding a rotor and the mechanical state of the rotor while it was operating in both steady and flutter modes to provide a basis for future analysis and for development of theories describing the flutter phenomenon. The program revealed that while all blades flutter at the same frequency, they do not flutter at the same amplitude, and their interblade phase angles are not equal. Such a pattern represents the superposition of a number of rotating nodal diameter patterns, each characterized by a different amplitude and different phase indexing, but each rotating at a speed that results in the same flutter frequency as seen in the rotor system. Review of the steady pressure contours indicated that flutter may alter the blade passage pressure distribution. The unsteady pressure amplitude contour maps reveal regions of high unsteady pressure amplitudes near the leading edge, lower amplitudes near the trailing.

  5. The numerical simulation of subsonic flutter

    NASA Technical Reports Server (NTRS)

    Strganac, Thomas W.; Mitchum, Maria V.; Mook, Dean T.

    1987-01-01

    The present paper describes a numerical simulation of unsteady, subsonic aeroelastic responses. The technique accounts for aerodynamic nonlinearities associated with angles of attack, vortex-dominated flow, static deformations, and unsteady behavior. The fluid and the wing together are treated as a single dynamic system, and the equations of motion for the structure and flowfield are integrated simultaneously and interactively in the time domain. The method employs an iterative scheme based on a predictor-corrector technique. The aerodynamic loads are computed by the general unsteady vortex-lattice method and are determined simultaneously with the motion of the wing. Two models are used to demonstrate the technique: a rigid wing on an elastic support experiencing plunge and pitch about the elastic axis, and a continuous wing rigidly supported at the root chord experiencing spanwise bending and twisting. The time domain solution coupled with the unsteady vortex-lattice method provides the capability of graphically depicting wing and wake motion. Several graphs that illustrate the time domain behavior of the wing and wake are presented.

  6. Subsonic Aircraft With Regression and Neural-Network Approximators Designed

    NASA Technical Reports Server (NTRS)

    Patnaik, Surya N.; Hopkins, Dale A.

    2004-01-01

    At the NASA Glenn Research Center, NASA Langley Research Center's Flight Optimization System (FLOPS) and the design optimization testbed COMETBOARDS with regression and neural-network-analysis approximators have been coupled to obtain a preliminary aircraft design methodology. For a subsonic aircraft, the optimal design, that is the airframe-engine combination, is obtained by the simulation. The aircraft is powered by two high-bypass-ratio engines with a nominal thrust of about 35,000 lbf. It is to carry 150 passengers at a cruise speed of Mach 0.8 over a range of 3000 n mi and to operate on a 6000-ft runway. The aircraft design utilized a neural network and a regression-approximations-based analysis tool, along with a multioptimizer cascade algorithm that uses sequential linear programming, sequential quadratic programming, the method of feasible directions, and then sequential quadratic programming again. Optimal aircraft weight versus the number of design iterations is shown. The central processing unit (CPU) time to solution is given. It is shown that the regression-method-based analyzer exhibited a smoother convergence pattern than the FLOPS code. The optimum weight obtained by the approximation technique and the FLOPS code differed by 1.3 percent. Prediction by the approximation technique exhibited no error for the aircraft wing area and turbine entry temperature, whereas it was within 2 percent for most other parameters. Cascade strategy was required by FLOPS as well as the approximators. The regression method had a tendency to hug the data points, whereas the neural network exhibited a propensity to follow a mean path. The performance of the neural network and regression methods was considered adequate. It was at about the same level for small, standard, and large models with redundancy ratios (defined as the number of input-output pairs to the number of unknown coefficients) of 14, 28, and 57, respectively. In an SGI octane workstation (Silicon Graphics

  7. Mode interactions of a high-subsonic deep cavity

    NASA Astrophysics Data System (ADS)

    Chen, Zhenli; Adams, Nikolaus A.

    2017-05-01

    To understand the interactions of the acoustic modes associated with the tunnel walls and the cavity oscillations in the experiment, flows over a deep cavity having a length-to-depth ratio L/D = 0.42 at high subsonic speeds with and without an upper tunnel wall were investigated by using an implicit large-eddy simulation with an adaptive local deconvolution method. The results of the simulations with the upper tunnel wall converge well to the experimental results as the resolution increases. However, in the simulations without the upper tunnel wall the flow converges to a different mean state. The mode interactions were analyzed by using a Dynamic Mode Decomposition (DMD) method based on a memory-efficient snapshot algorithm. It was found that nearly trapped global modes, which have almost zero upstream and downstream radiation, can occur. The interactions of the trapped modes, the acoustic resonant modes in the cavity, and the shear-layer modes can be observed in the DMD modes of the flow with the upper tunnel wall, which results in the enhancement of harmonic modes and the existence of higher-order modes. In the flow without the upper tunnel wall, the pressure waves can transmit freely away from the cavity, but the interactions of the acoustic resonant modes and the shear-layer modes can also be observed when the frequencies of both kinds of modes coincide. The effects of the ratio of the cavity depth to the tunnel height (D/H) on the formation of trapped modes were also investigated. As the ratio D/H decreases, the frequency window of the trapped modes shrinks and finally closes, which is consistent with a theoretical model. It can be concluded that the effects of the upper tunnel wall on the dynamics of the cavity flow are strong and are promoted by the interactions of different kinds of modes. The appearance and enhancement of high order harmonic modes in the high-subsonic deep cavity are due to the effects of the trapped modes, but are not due to the directly

  8. Aeolian Sediment Transport through Large Patches of Roughness in the Atmospheric Inertial Sublayer

    NASA Technical Reports Server (NTRS)

    Gillies, John A.; Nickling, Willilam G.; King, James

    2006-01-01

    Roughness influences the flux of wind driven sand transport. In this paper, we report on sediment transport measurements for four different surface roughness configurations composed of the same size (solid) roughness elements in the atmospheric inertial sublayer (ISL). Results of these tests indicate that sediment transport rates through patches of roughness in the atmospheric inertial sublayer are to a large extent controlled and scale proportionally with the roughness density (lambda = n b h/S, where n is number of elements of breadth b and height h in area S) of the surface. However, element size apparently increases the magnitude of the reduction beyond that attributable to lambda. A sediment transport model that incorporates the effect of shear stress partitioning appears to predict reasonably well the effect of roughness on sand transport in the cases where the roughness elements are less than or equal to 0.10 m in height. However, when the dimensions of the roughness itself are equivalent to or are greater than the range of saltation lengths (vertical and horizontal), additional interactions of the elements with the saltation cloud appear to reduce the transport efficiency.

  9. Aeolian Sediment Transport through Large Patches of Roughness in the Atmospheric Inertial Sublayer

    NASA Technical Reports Server (NTRS)

    Gillies, John A.; Nickling, Willilam G.; King, James

    2006-01-01

    Roughness influences the flux of wind driven sand transport. In this paper, we report on sediment transport measurements for four different surface roughness configurations composed of the same size (solid) roughness elements in the atmospheric inertial sublayer (ISL). Results of these tests indicate that sediment transport rates through patches of roughness in the atmospheric inertial sublayer are to a large extent controlled and scale proportionally with the roughness density (lambda = n b h/S, where n is number of elements of breadth b and height h in area S) of the surface. However, element size apparently increases the magnitude of the reduction beyond that attributable to lambda. A sediment transport model that incorporates the effect of shear stress partitioning appears to predict reasonably well the effect of roughness on sand transport in the cases where the roughness elements are less than or equal to 0.10 m in height. However, when the dimensions of the roughness itself are equivalent to or are greater than the range of saltation lengths (vertical and horizontal), additional interactions of the elements with the saltation cloud appear to reduce the transport efficiency.

  10. Conservation laws for collisional and turbulent transport processes in toroidal plasmas with large mean flows

    NASA Astrophysics Data System (ADS)

    Sugama, H.; Nunami, M.; Nakata, M.; Watanabe, T.-H.

    2017-02-01

    A novel gyrokinetic formulation is presented by including collisional effects into the Lagrangian variational principle to yield the governing equations for background and turbulent electromagnetic fields and gyrocenter distribution functions, which can simultaneously describe classical, neoclassical, and turbulent transport processes in toroidal plasmas with large toroidal flows on the order of the ion thermal velocity. Noether's theorem modified for collisional systems and the collision operator given in terms of Poisson brackets are applied to derivation of the particle, energy, and toroidal momentum balance equations in the conservative forms, which are desirable properties for long-time global transport simulation.

  11. Dentate transport discs can be used to reconstruct large segmental mandibular defects

    PubMed Central

    Elsalanty, Mohammed E.; Malavia, Veera; Zakhary, Ibrahim; Mulone, Timothy; Kontogiorgos, Elias D.; Dechow, Paul C.; Opperman, Lynne A.

    2015-01-01

    Purpose This study tests the use of a dentate transport segment for the reconstruction of a large U-shaped defect in the anterior segment of the canine mandible, using a novel curved reconstruction plate. The quality and quantity of bone regenerate formed by dentate versus edentulous transport segments was compared. Methods In five adult foxhound dogs, a defect of 70–75 mm was created in the canine mandible by excising the mandible anterior to the right and left 4th premolars. Reconstruction was done by trifocal distraction osteogenesis using a bone transport reconstruction plate (BTRP-02™), with two transport units being activated simultaneously, one on either side of the defect, one dentate and one edentulous. Bilateral distraction proceeded at a rate of 1mm/day until the segments docked against each other in midline. After 39–44 days consolidation, the animals were euthanized. The quantity and quality of bone regeneration on both sides were compared using micro-computed tomography. Results The defect reconstruction was successful. The amount and quality of bone formed by the transport segments was similar on both sides. There were no significant differences in the bone volume fraction and density of the regenerate bone formed by the two transport segments. The bone volume fraction and density of the regenerate was significantly lower than that of the host bone in the distal segments, likely due to the short consolidation period. Conclusions Bone transport remains a viable option in reconstructing anterior segmental defects in the mandible. The use of either dentate or edentulous transport segments for reconstruction provides options for the surgeon in often highly compromised patients requiring these surgeries. PMID:25661502

  12. Coherent structures and wavepackets in subsonic transitional turbulent jets

    NASA Astrophysics Data System (ADS)

    Yang, Haihua; Zhang, Xingchen; Ran, Lingke; Sun, Dejun; Wan, Zhenhua

    2017-02-01

    A large eddy simulation (LES) is performed for two subsonic jets with a Reynolds number of Re=10^5, which have different core temperatures, i.e., the cold and hot jet. The far-field overall sound pressure levels (OASPL) and noise spectra are well validated against previous experimental results. It is found that the OASPL is raised by heating at shallow angles. The most energetic coherent structures are extracted with specified frequencies using the filter based on the frequency domain variant of the snapshot method of proper orthogonal decomposition (POD). The m=0,1 modes have high coherence of near-field pressure for both jets, while the coherence of m=0 modes is enhanced greatly by heating. Based on the coherent structures, spatial wavepackets are educed and the characteristics of growth, saturation and decay are analyzed and compared between the two jets in detail. The results show that heating would enhance the linear growth rate for high frequency components, and nonlinear growth rates for low frequency components in general, which are responsible for higher OASPL in the hot jet. The far-field sound generated by wavepackets is computed using the Kirchhoff extrapolation, which matches well with that of LES at shallow angles. This indicates that the wavepackets associated with coherent structures are dominant sound sources in forced transitional turbulent jets. Additionally, the present POD method is proven to be a robust tool to extract the salient features of the wavepackets in turbulent flows.

  13. Cavity Unsteady-Pressure Measurements at Subsonic and Transonic Speeds

    NASA Technical Reports Server (NTRS)

    Tracy, Maureen B.; Plentovich, E. B.

    1997-01-01

    An experimental investigation was conducted in the Langley 8-Foot Transonic Pressure Tunnel to determine the flow characteristics of rectangular cavities with varying relative dimensions at subsonic and transonic speeds. Cavities were tested with width-to-depth ratios of 1, 4, 8, and 16 for length-to-depth ratios l/h of 1 through 17.5. The maximum cavity depth was 2.4 in., and the turbulent boundary layer approaching the cavity was approximately 0.5 in. thick. Unsteady- and mean static-pressure measurements were made at free-stream Mach numbers from 0.20 to 0.95 at a unit Reynolds number per foot of approximately 3 x 10(exp 6); however, only unsteady-pressure results are presented in this paper. Results indicate that as l/h increases, cavity flows changed from resonant to nonresonant with resonant amplitudes decreasing gradually. Resonant spectra are obtained largely in cavities with mean static-pressure distributions characteristic of open and transitional flows. Resonance sometimes occurred for closed flow. Increasing cavity width or decreasing cavity depth while holding l/h fixed had the effect of increasing resonant amplitudes and sometimes induced resonance. The effects due to changes in width are more pronounced. Decreasing Mach number has the effect of broadening the resonances.

  14. Response of High Subsonic Jet to Nonaxisymmetric Disturbances

    NASA Technical Reports Server (NTRS)

    Bayliss, A.; Maestrello, L.

    1997-01-01

    A model of sound generated in a high subsonic (Mach 0.9) circular jet is solved numerically in cylindrical coordinates for nonaxisymmetric disturbances. The jet is excited by transient mass injection by a finite duration pulse via a modulated ring source. The nonaxisymmetric solution is computed for long times after the initial disturbance has exited the computational domain. The long time behavior of the jet is dominated by vorticity and pressure disturbances generated at the nozzle lip and growing as they convect down-stream in the jet. These disturbances generate sound as they propagate. The primary non-axisymmetric effect that we simulate is that of a flapping mode where regions of high and low pressure alternate on opposite sides of the jet. The predominant feature of this mode is the appearance of relatively large deviations of the pressure from the ambient pressure on opposite sides of the jet and the convection of these regions downstream. We illustrate flow field, near field and far field data. Important nonaxisymmetric characteristics of the near and flow field disturbances include roughly periodic pressure elevations and depressions at opposite values of the azimuthal angle psi. These correspond to pressure disturbances propagating in the axial direction. The azimuthal velocity exhibits a sinusoidal dependence on psi with similar roughly periodic disturbances. For every azimuthal angle psi, the jet radiation peaks about 30 deg. from the jet axis, however there is now a pronounced dependence of the far field radiation pattern on psi.

  15. Effect of submerged vegetation on solute transport in an open channel using large eddy simulation

    NASA Astrophysics Data System (ADS)

    Lu, J.; Dai, HC

    2016-11-01

    Existence of vegetation plays a significant effect on the flow velocity distributions, turbulence structures and solute mixing in an open channel. This paper has implemented a 3D large eddy simulation model for the flow and scalar transport in the open channel with vegetation. The model can produce a typical turbulence characteristics and concentration distribution with vegetation. The scalar transport mechanism is quantitatively explained by the turbulent Schmidt number, Reynolds flux, coherent structures and quadrant conditional analysis. A dominance of ejection-sweeping events occurs in the process of the momentum and scalar flux transport. The spectral analysis is used to identify the Kelvin-Helmholtz frequency. The turbulence characteristics of the length scale of vortexes, Kelvin-Helmholtz frequency and Reynolds stress etc. are analyzed with the vegetation density. The model quantitatively predicts the trend of decreasing in the concentration distribution along the flow direction with the increasing of vegetation density.

  16. Pangolin v1.0, a conservative 2-D transport model for large scale parallel calculation

    NASA Astrophysics Data System (ADS)

    Praga, A.; Cariolle, D.; Giraud, L.

    2014-07-01

    To exploit the possibilities of parallel computers, we designed a large-scale bidimensional atmospheric transport model named Pangolin. As the basis for a future chemistry-transport model, a finite-volume approach was chosen both for mass preservation and to ease parallelization. To overcome the pole restriction on time-steps for a regular latitude-longitude grid, Pangolin uses a quasi-area-preserving reduced latitude-longitude grid. The features of the regular grid are exploited to improve parallel performances and a custom domain decomposition algorithm is presented. To assess the validity of the transport scheme, its results are compared with state-of-the-art models on analytical test cases. Finally, parallel performances are shown in terms of strong scaling and confirm the efficient scalability up to a few hundred of cores.

  17. Analysis of Bifurcation Phenomena in the Electron Internal Transport Barrier in the Large Helical Device

    NASA Astrophysics Data System (ADS)

    García, J.; Yamazaki, K.; Dies, J.; Izquierdo, J.

    2006-03-01

    The electron internal transport barrier (eITB) formation in the Large Helical Device (LHD) is studied with the transport code TOTAL and a GyroBohm-like model. The reduction of anomalous transport by the E×B shear has been introduced by means of the factor [1+(τωE×B)γ]-1. Simulation results show a clear critical transition between plasma regimes with rather flat electron temperature profiles (non-eITB) to a steeped one (with eITB) when average density is low enough. With the aim of studying the eITB formation as a phase transition phenomenon, the electron average density is taken as the control parameter and the E×B shearing rate as the order parameter. Results show how the eITB formation in LHD is compatible with a continuum phase transition with critical exponent β=0.40.

  18. Study on utilization of advanced composites in fuselage structures of large transports

    NASA Technical Reports Server (NTRS)

    Johnson, R. W.; Thomson, L. W.; Wilson, R. D.

    1985-01-01

    The potential for utilizing advanced composites in fuselage structures of large transports was assessed. Six fuselage design concepts were selected and evaluated in terms of structural performance, weight, and manufacturing development and costs. Two concepts were selected that merit further consideration for composite fuselage application. These concepts are: (1) a full depth honeycomb design with no stringers, and (2) an I section stringer stiffened laminate skin design. Weight reductions due to applying composites to the fuselages of commercial and military transports were calculated. The benefits of applying composites to a fleet of military transports were determined. Significant technology issues pertinent to composite fuselage structures were identified and evaluated. Program plans for resolving the technology issues were developed.

  19. NUHOWS - Storage and Transportation of Irradiated Reactor Components in Large Packages - 13439

    SciTech Connect

    Rae, Glen A.

    2013-07-01

    Most irradiated reactor components (hardware such as Control Rod Blades, Fuel Channels, Poison Curtains, etc.) generated at reactors previously required significant processing for size reduction due to the available transportation casks not being physically capable of containing unprocessed material. As of July 1, 2008, disposal for this typical waste class (B and C) became inaccessible (for the major part of the nation) due to the Barnwell, SC disposal facility being closed to all but its three compact states (CT, NJ and SC). Currently in the United States, most facilities are storing their irradiated hardware on-site in the spent fuel pools. Until recently with the opening of the Waste Control Specialists' Texas disposal facility, utilities faced the challenges of spent fuel pool space and capacity management. However, even with WCS's disposal availability, the site currently has annual Curie limitations for disposal, which will continue to promote interim on-site storage until such time as disposal is available. In response, Transnuclear Inc., (TN) an AREVA company, proceeded with designing a new large Radioactive Waste Container (RWC) that can be used to package irradiated hardware without the need for significant processing. The design features of the RWC allows for intermittent loadings of the hardware for better packaging efficiency, higher packaging density, space savings and reduced cost. This RWC is also compatible with TN's on-site modular vault storage system. Once completely loaded, the RWC can be transported to an on-site storage facility, an off-site storage facility and/or an available disposal facility. To accommodate the transportation, TN has designed a large transportation cask, the MP197HB. As the original design was for transporting fuel, it contains the necessary shielding to allow for the transport of unprocessed irradiated reactor components, while significantly reducing the amount of irradiated hardware shipments required with the use of

  20. Networking for large-scale science: infrastructure, provisioning, transport and application mapping

    NASA Astrophysics Data System (ADS)

    Rao, Nageswara S.; Carter, Steven M.; Wu, Qishi; Wing, William R.; Zhu, Mengxia; Mezzacappa, Anthony; Veeraraghavan, Malathi; Blondin, John M.

    2005-01-01

    Large-scale science computations and experiments require unprecedented network capabilities in the form of large bandwidth and dynamically stable connections to support data transfers, interactive visualizations, and monitoring and steering operations. A number of component technologies dealing with the infrastructure, provisioning, transport and application mappings must be developed and/or optimized to achieve these capabilities. We present a brief account of the following technologies that contribute toward achieving these network capabilities: (a) DOE UltraScienceNet and NSF CHEETAH network testbeds that provide on-demand and scheduled dedicated network connections; (b) experimental results on transport protocols that achieve close to 100% utilization on dedicated 1Gbps wide-area channels; (c) a scheme for optimally mapping a visualization pipeline onto a network to minimize the end-to-end delays; and (d) interconnect configuration and protocols that provides multiple Gbps flows from Cray X1 to external hosts.

  1. Aeroelasticity Benchmark Assessment: Subsonic Fixed Wing Program

    NASA Technical Reports Server (NTRS)

    Florance, Jennifer P.; Chwalowski, Pawel; Wieseman, Carol D.

    2010-01-01

    Aeroelasticity Branch will examine other experimental efforts within the Subsonic Fixed Wing (SFW) program (such as testing of the NASA Common Research Model (CRM)) and other NASA programs and assess aeroelasticity issues and research topics.

  2. Mass and dust transport by atmospheric thermal circulations forced by large topographic features on Mars.

    NASA Astrophysics Data System (ADS)

    Rafkin, S. C. R.; Sta. Maria, M. R.; Michaels, T. I.

    2002-09-01

    The existance of mesoscale atmospheric circulations on Mars is well documented, primarly through images of enhanced dust loading and clouds which arise due to these circulations. The Mars Orbiter Camera imaged one such feature--a spiral dust cloud--over the caldera of Arsia Mons. We use the Mars Regional Atmospheric Modeling System to investigate the underlying dynamics of the dust cloud. Results show that the cloud feature is the visible portion of a much larger thermal circulation that vents boundary layer air to an altitude in excess of 30 km on time scales of only a few hours. At the top of the circulation, air and dust is transported horizontally over several thousand kilometers. The circulation is a warm-core low pressure system that has a structure not unlike hurricanes on Earth. Similar circulations are thought to be forced by other large topographic features. When taken as an ensemble, the mass flux and transport capabilities of these circulations may well be sufficient to maintain the background atmospheric dust load, and may play a crucial role in the transport of water and other volatiles. The transport by the circulations is also placed in the context of the slow and relatively diffusive transport of the Hadley Cell circulation.

  3. Sediment transport dynamics in the swash zone under large-scale laboratory conditions

    NASA Astrophysics Data System (ADS)

    Ruju, Andrea; Conley, Daniel; Masselink, Gerd; Puleo, Jack

    2016-06-01

    A laboratory experiment was carried out to study sediment transport dynamics occurring in the swash zone of a coarse-sandy beach built in a large-scale wave flume. Hydro- and morpho-dynamic as well as sediment transport data were collected using sensors mounted on a scaffold rig deployed in the lower swash zone close to the moving bed. The high resolution of near-bed data permitted quantitative evaluation of suspended and sheet flow contributions to the total sediment transport. Although sheet flow sediment fluxes were higher than suspended fluxes, the vertically integrated suspended sediment load overcame the sheet flow load during uprush and it was on the same order of magnitude during backwash. The observed cumulative sediment transport was generally larger than the morphological changes occurring shoreward of the rig location implying either an underestimation of the offshore sediment transport or an overestimation of the onshore fluxes obtained from concentration and velocity profile data. Low correlations were found between net swash profile changes and runup parameters suggesting that local hydrodynamic parameters provide little or no predictability of accretion and erosion of an upper beach which is near equilibrium. The balance between erosion and deposition induced by individual swash events brought a dynamic equilibrium with small differences between the profiles measured at the start and at the end of the run.

  4. Rules of the road: A qualitative and quantitative synthesis of large wood transport through drainage networks

    NASA Astrophysics Data System (ADS)

    Kramer, Natalie; Wohl, Ellen

    2017-02-01

    To effectively manage wood in rivers, we need a better understanding of wood mobility within river networks. Here, we review primarily field-based (and some numerical) studies of wood transport. We distinguish small, medium, large, and great rivers based on wood piece dimensions relative to channel and flow dimensions and dominant controls on wood transport. We suggest further identification and designation of wood transport regimes as a useful way to characterize spatial-temporal network heterogeneity and to conceptualize the primary controls on wood mobility in diverse river segments. We draw analogies between wood and bedload transport, including distinguishing Eulerian and Lagrangian approaches, exploring transport capacity, and quantifying thresholds of wood mobility. We identify mobility envelopes for remobilization of wood with relation to increasing peak discharges, stream size, and dimensionless log lengths. Wood transport in natural channels exhibits high spatial and temporal variability, with discontinuities along the channel network at bankfull flow and when log lengths equal channel widths. Although median mobilization rates increase with increasing channel size, maximum mobilization rates are greatest in medium-sized channels. Most wood is transported during relatively infrequent high flows, but flows under bankfull can transport up to 30% of stored wood. We use conceptual models of dynamic equilibrium of wood in storage and of spiralling wood transport paths through drainage networks, as well as a metaphor of traffic on a road, to explore discontinuous wood movement through a river network. The primary limitations to describing wood transport are inappropriate time scales of observation and lack of sufficient data on mobility from diverse rivers. Improving models of wood flux requires better characterization of average step lengths within the lifetime travel path of a piece of wood. We suggest that future studies focus on: (i) continuous or high

  5. Reconstruction of large mandibular bone and soft-tissue defect using bone transport distraction osteogenesis.

    PubMed

    Elsalanty, Mohammed E; Taher, Taher N; Zakhary, Ibrahim E; Al-Shahaat, Osama A; Refai, Mohammed; El-Mekkawi, Hatem A

    2007-11-01

    Reconstruction of large anterior mandibular defects is a challenging task. The condition can become even more complex if primary reconstruction fails, leading to loss of the entire midline portion of the lower face with massive scarring of the remaining tissues. Bone transport distraction osteogenesis can provide a viable treatment option for these patients. One of such cases will be presented, followed by a discussion of the advantages, disadvantages, and limitations of the technique.

  6. Development of pressure containment and damage tolerance technology for composite fuselage structures in large transport aircraft

    NASA Technical Reports Server (NTRS)

    Smith, P. J.; Thomson, L. W.; Wilson, R. D.

    1986-01-01

    NASA sponsored composites research and development programs were set in place to develop the critical engineering technologies in large transport aircraft structures. This NASA-Boeing program focused on the critical issues of damage tolerance and pressure containment generic to the fuselage structure of large pressurized aircraft. Skin-stringer and honeycomb sandwich composite fuselage shell designs were evaluated to resolve these issues. Analyses were developed to model the structural response of the fuselage shell designs, and a development test program evaluated the selected design configurations to appropriate load conditions.

  7. HYDRODYNAMICS AND SEDIMENT TRANSPORT IN LOWER MISSISSIPPI RIVER MEANDER BENDS (LOUISIANA): IMPLICATIONS FOR LARGE SEDIMENT DIVERSIONS

    NASA Astrophysics Data System (ADS)

    Allison, M. A.; McCorquodale, A.; Meselhe, E. A.

    2009-12-01

    Field data collection and numerical modeling is being conducted in the lower Mississippi River in the region of a meander bend at Myrtle Grove, LA (river km 96 above Head of Passes) in support of a proposed large water and sediment diversion (1,130-2,830 cms) for coastal wetland restoration. Field studies in October 2008, April and May 2009, at discharges ranging from 11,000-21,000 cms, examined the role of bend dynamics on sediment transport through this reach relative to control sites further downriver and USGS monitoring stations upriver. Suspended loads and grain size character measured by ADCP (velocities and backscatter), isokinetic point sampler (P-63), and optical sensors (LISST, OBS, transmissometer) indicate that during the rising-to-high discharge phase, sand lifting off from the downstream edge of the lateral bar upriver of the bend augments that carried from further upriver, and is entrained in the upper 10-25m of the water column. This excess suspended sand is advected around the bend before concentrations are reduced to background levels over the lateral bar downstream of the bend. Bedload transport rates measured by repeat swath bathymetric mapping of migrating dunes are comparable upstream of the bend, downstream, and in the control sites. However, no bedforms are observed in the bend thalweg (up to 60 m deep) supporting the dominance of suspended sand transport in the bend. Both 1D (HEC-RAS and HEC6-T) and 3D (Flow3D) numerical hydrodynamic and sediment transport modeling is underway to simulate this process and the large-scale eddy present in the bend that generates upriver transport along the inside of the meander bend at all observed discharges. Our preliminary results suggest that the outside of meander bends might be an appropriate site for sediment diversions that draw near-surface water from this sediment-rich layer.

  8. Subsonic potential aerodynamics for complex configurations - A general theory

    NASA Technical Reports Server (NTRS)

    Morino, L.; Kuo, C.-C.

    1974-01-01

    A general theory of subsonic potential aerodynamic flow around a lifting body having arbitrary shape and motion is presented. By using the Green function method, an integral representation for the velocity potential is obtained for both supersonic and subsonic flow. Under the small perturbation assumption, the potential at any point in the field depends only upon the values of the potential and its normal derivative on the surface of the body. On the surface of the body, this representation reduces to an integro-differential equation relating the potential and its normal derivative (which is known from the boundary conditions) on the surface. The theory is applied to finite-thickness wings in subsonic steady and oscillatory flows.

  9. Subsonic loads on wings having sharp leading edges and tips

    NASA Technical Reports Server (NTRS)

    Kandil, O. A.; Mook, D. T.; Nayfeh, A. H.

    1976-01-01

    A vortex-lattice method for predicting the aerodynamics of wings having separation at the sharp edges in incompressible flows is extended to compressible subsonic flows using a modified Prandtl-Glauert transformation. Numerical results showing the effect of freestream Mach number on the aerodynamic coefficients are compared with available experimental data for several planforms. It is shown that the proposed method is suitable for predicting the aerodynamic loads on low-aspect wings at moderate angles of attack for high subsonic freestream Mach number. The method is limited to angles of attack up to 12 deg for high subsonic freestream Mach number and to angles of attack up to 20 deg for Mach number not exceeding 0.5.

  10. Moditored unsaturated soil transport processes as a support for large scale soil and water management

    NASA Astrophysics Data System (ADS)

    Vanclooster, Marnik

    2010-05-01

    The current societal demand for sustainable soil and water management is very large. The drivers of global and climate change exert many pressures on the soil and water ecosystems, endangering appropriate ecosystem functioning. The unsaturated soil transport processes play a key role in soil-water system functioning as it controls the fluxes of water and nutrients from the soil to plants (the pedo-biosphere link), the infiltration flux of precipitated water to groundwater and the evaporative flux, and hence the feed back from the soil to the climate system. Yet, unsaturated soil transport processes are difficult to quantify since they are affected by huge variability of the governing properties at different space-time scales and the intrinsic non-linearity of the transport processes. The incompatibility of the scales between the scale at which processes reasonably can be characterized, the scale at which the theoretical process correctly can be described and the scale at which the soil and water system need to be managed, calls for further development of scaling procedures in unsaturated zone science. It also calls for a better integration of theoretical and modelling approaches to elucidate transport processes at the appropriate scales, compatible with the sustainable soil and water management objective. Moditoring science, i.e the interdisciplinary research domain where modelling and monitoring science are linked, is currently evolving significantly in the unsaturated zone hydrology area. In this presentation, a review of current moditoring strategies/techniques will be given and illustrated for solving large scale soil and water management problems. This will also allow identifying research needs in the interdisciplinary domain of modelling and monitoring and to improve the integration of unsaturated zone science in solving soil and water management issues. A focus will be given on examples of large scale soil and water management problems in Europe.

  11. Effects of woody vegetation on overbank sand transport during a large flood, Rio Puerco, New Mexico

    USGS Publications Warehouse

    Griffin, Eleanor R.; Perignon, Mariela C.; Friedman, Jonathan M.; Tucker, Gregory E.

    2014-01-01

    Distributions of woody vegetation on floodplain surfaces affect flood-flow erosion and deposition processes. A large flood along the lower Rio Puerco, New Mexico, in August 2006 caused extensive erosion in a reach that had been sprayed with herbicide in September 2003 for the purpose of saltcedar (Tamarix spp.) control. Large volumes of sediment, including a substantial fraction of sand, were delivered to the reach downstream, which had not been treated with herbicide. We applied physically based, one-dimensional models of flow and suspended-sediment transport to compute volume concentrations of sand in suspension in floodplain flow at a site within the sprayed reach and at a site downstream from the sprayed reach. We computed the effects of drag on woody stems in reducing the skin friction shear stress, velocity of flow, and suspended-sand transport from open paths into patches of dense stems. Total flow and suspended-sand fluxes were computed for each site using well-constrained flood-flow depths, water-surface slopes, and measured shrub characteristics. Results show that flow in open paths carried high concentrations of sand in suspension with nearly uniform vertical distributions. Drag on woody floodplain stems reduced skin friction shear stresses by two orders of magnitude, yet sufficient velocities were maintained to transport sand more than 50 m into fields of dense, free-surface-penetrating stems. An increase in shrub canopy extent from 31% in the sprayed reach site to 49% in the downstream site was found to account for 69% of the computed decrease in discharge between the two sites. The results demonstrate the need to compute the spatial distribution of skin friction shear stress in order to effectively compute suspended-sand transport and to predict the fate of sediment and contaminants carried in suspension during large floods.

  12. Effects of woody vegetation on overbank sand transport during a large flood, Rio Puerco, New Mexico

    NASA Astrophysics Data System (ADS)

    Griffin, Eleanor R.; Perignon, Mariela C.; Friedman, Jonathan M.; Tucker, Gregory E.

    2014-02-01

    Distributions of woody vegetation on floodplain surfaces affect flood-flow erosion and deposition processes. A large flood along the lower Rio Puerco, New Mexico, in August 2006 caused extensive erosion in a reach that had been sprayed with herbicide in September 2003 for the purpose of saltcedar (Tamarix spp.) control. Large volumes of sediment, including a substantial fraction of sand, were delivered to the reach downstream, which had not been treated with herbicide. We applied physically based, one-dimensional models of flow and suspended-sediment transport to compute volume concentrations of sand in suspension in floodplain flow at a site within the sprayed reach and at a site downstream from the sprayed reach. We computed the effects of drag on woody stems in reducing the skin friction shear stress, velocity of flow, and suspended-sand transport from open paths into patches of dense stems. Total flow and suspended-sand fluxes were computed for each site using well-constrained flood-flow depths, water-surface slopes, and measured shrub characteristics. Results show that flow in open paths carried high concentrations of sand in suspension with nearly uniform vertical distributions. Drag on woody floodplain stems reduced skin friction shear stresses by two orders of magnitude, yet sufficient velocities were maintained to transport sand more than 50 m into fields of dense, free-surface-penetrating stems. An increase in shrub canopy extent from 31% in the sprayed reach site to 49% in the downstream site was found to account for 69% of the computed decrease in discharge between the two sites. The results demonstrate the need to compute the spatial distribution of skin friction shear stress in order to effectively compute suspended-sand transport and to predict the fate of sediment and contaminants carried in suspension during large floods.

  13. Electron heat transport comparison in the Large Helical Device and TJ-II

    NASA Astrophysics Data System (ADS)

    García, J.; Dies, J.; Castejón, F.; Yamazaki, K.

    2007-10-01

    The electron heat transport in the Large Helical Device (LHD) [K. Ida, T. Shimozuma, H. Funaba et al., Phys. Rev. Lett. 91, 085003 (2003)] and TJ-II [F. Castejón, V. Tribaldos, I. García-Cortés, E. de la Luna, J. Herranz, I. Pastor, T. Estrada, and TJ-II Team, Nucl. Fusion 42, 271 (2002)] is analyzed by means of the TOTAL [K. Yamazaki and T. Amano, Nucl. Fusion 32, 4 (1992)] and PRETOR-Stellarator [J. Dies, F. Castejon, J. M. Fontdecaba, J. Fontanet, J. Izquierdo, G. Cortes, and C. Alejaldre, Proceedings of the 29th European Physical Society Conference on Plasma Physics and Controlled Fusion, Montreux, 2002, Europhysics Conference Abstracts, 2004, Vol. 26B, P-5.027] plasma simulation codes and assuming a global transport model mixing GyroBohm-like drift wave model and other drift wave model with shorter wavelength. The stabilization of the GyroBohm-like model by the E ×B shear has been also taken into account. Results show how such kind of electron heat transport can simulate experimental evidence in both devices, leading to the electron internal transport barrier (eITB) formation in the LHD and to the so-called "enhanced heat confinement regimes" in TJ-II when electron density is low enough. Therefore, two sources for the anomalous electron heat transport can coexist in plasmas with eITB; however, for each device the relative importance of anomalous and neoclassical transport can be different.

  14. Acoustic mode in numerical calculations of subsonic combustion

    SciTech Connect

    O'Rourke, P.J.

    1984-01-01

    A review is given of the methods for treating the acoustic mode in numerical calculations of subsonic combustion. In numerical calculations of subsonic combustion, treatment of the acoustic mode has been a problem for many researchers. It is widely believed that Mach number and acoustic wave effects are negligible in many subsonic combustion problems. Yet, the equations that are often solved contain the acoustic mode, and many numerical techniques for solving these equations are inefficient when the Mach number is much smaller than one. This paper reviews two general approaches to ameliorating this problem. In the first approach, equations are solved that ignore acoustic waves and Mach number effects. Section II of this paper gives two such formulations which are called the Elliptic Primitive and the Stream and Potential Function formulations. We tell how these formulations are obtained and give some advantages and disadvantages of solving them numerically. In the second approach to the problem of calculating subsonic combustion, the fully compressible equations are solved by numerical methods that are efficient, but treat the acoustic mode inaccurately, in low Mach number calculations. Section III of this paper introduces two of these numerical methods in the context of an analysis of their stability properties when applied to the acoustic wave equations. These are called the ICE and acoustic subcycling methods. It is shown that even though these methods are more efficient than traditional methods for solving subsonic combustion problems, they still can be inefficient when the Mach number is very small. Finally, a method called Pressure Gradient Scaling is described that, when used in conjunction with either the ICE or acoustic subcycling methods, allows for very efficient numerical solution of subsonic combustion problems. 11 refs.

  15. Low-stress mounting configuration design for large aperture laser transport mirror

    NASA Astrophysics Data System (ADS)

    Zhang, Zheng; Quan, Xusong; Yao, Chao; Wang, Hui

    2016-10-01

    TM1-6S1 large aperture laser transport mirror is a crucial optical unit of high power solid-state laser in the Inertial Confinement Fusion (ICF) facility. This article focuses on the low-stress and precise mounting method of large-aperture mirror. Based on the engineering practice of SG-III, the state-of-the-art and key problems of current mounting configuration are clarified firstly. Subsequently, a brand new low-stress mounting configuration with flexure supports is proposed. Opto-mechanical model of the mirror under mounting force is built up with elastic mechanics theory. Further, numerical methods and field tests are employed to verify the favorable load uniform capacity and load adjust capacity of flexure supports. With FEM, the relation between the mounting force from new configuration and the mirror surface distortion (wavefront error) is clarified. The novel mounting method of large aperture optics could be not only used on this laser transport mirror, but also on the other transmission optics and large crystals in ICF facilities.

  16. Suspended sediment transport trough a large fluvial-tidal channel network

    USGS Publications Warehouse

    Wright, Scott A.; Morgan-King, Tara L.

    2015-01-01

    The confluence of the Sacramento and San Joaquin Rivers, CA, forms a large network of interconnected channels, referred to as the Sacramento-San Joaquin Delta (the Delta). The Delta comprises the transition zone from the fluvial influences of the upstream rivers and tidal influences of San Francisco Bay downstream. Formerly an extensive tidal marsh, the hydrodynamics and geomorphology of Delta have been substantially modified by humans to support agriculture, navigation, and water supply. These modifications, including construction of new channels, diking and draining of tidal wetlands, dredging of navigation channels, and the operation of large pumping facilities for distribution of freshwater from the Delta to other parts of the state, have had a dramatic impact on the physical and ecological processes within the Delta. To better understand the current physical processes, and their linkages to ecological processes, the USGS maintains an extensive network of flow, sediment, and water quality gages in the Delta. Flow gaging is accomplished through use of the index-velocity method, and sediment monitoring uses turbidity as a surrogate for suspended-sediment concentration. Herein, we present analyses of the transport and dispersal of suspended sediment through the complex network of channels in the Delta. The primary source of sediment to the Delta is the Sacramento River, which delivers pulses of sediment primarily during winter and spring runoff events. Upon reaching the Delta, the sediment pulses move through the fluvial-tidal transition while also encountering numerous channel junctions as the Sacramento River branches into several distributary channels. The monitoring network allows us to track these pulses through the network and document the dominant transport pathways for suspended sediment. Further, the flow gaging allows for an assessment of the relative effects of advection (the fluvial signal) and dispersion (from the tides) on the sediment pulses as they

  17. Large Eddy Simulation of Motion-Induced Contaminant Transports in Room Compartments

    NASA Astrophysics Data System (ADS)

    Choi, Jung-Il; Edwards, Jack

    2011-11-01

    Large eddy simulation (LES) of contaminant transports due to complex human and door motions is conducted for characterizing the effect of the motion-induced wakes on the contaminant transports in room compartments where a contaminated and clean room are connected by a vestibule. We utilize a LES technique with an immersed-boundary method for moving objects (Choi et al., JCP 2007; Choi and Edwards, Indoor Air 2008) and extend the technique to include Eulerian descriptions of gas-phase contaminant transport as well as thermal energy transfer. We demonstrate details of contaminant transport due to human- and door-motion induced wake development during a short-duration event involving the movement of a person (or persons) from a contaminated room, through a vestibule, into a clean room. Parametric studies that capture the effects of human walking pattern, door operation, over-pressure level, and vestibule size are systematically conducted. The results of parameteric studies will be shown in the final presentation. Supported by DARPA/SPO program (HR0011-05-C-0157) and WCU program (R31-10049) of NRF.

  18. Large cargo transport by nuclear pores: implications for the spatial organization of FG-nucleoporins

    PubMed Central

    Tu, Li-Chun; Fu, Guo; Zilman, Anton; Musser, Siegfried M

    2013-01-01

    Nuclear pore complexes (NPCs) mediate cargo traffic between the nucleus and the cytoplasm of eukaryotic cells. Nuclear transport receptors (NTRs) carry cargos through NPCs by transiently binding to phenylalanine-glycine (FG) repeats on intrinsically disordered polypeptides decorating the NPCs. Major impediments to understand the transport mechanism are the thousands of FG binding sites on each NPC, whose spatial distribution is unknown, and multiple binding sites per NTR, which leads to multivalent interactions. Using single molecule fluorescence microscopy, we show that multiple NTR molecules are required for efficient transport of a large cargo, while a single NTR promotes binding to the NPC but not transport. Particle trajectories and theoretical modelling reveal a crucial role for multivalent NTR interactions with the FG network and indicate a non-uniform FG repeat distribution. A quantitative model is developed wherein the cytoplasmic side of the pore is characterized by a low effective concentration of free FG repeats and a weak FG-NTR affinity, and the centrally located dense permeability barrier is overcome by multivalent interactions, which provide the affinity necessary to permeate the barrier. PMID:24213245

  19. Large cargo transport by nuclear pores: implications for the spatial organization of FG-nucleoporins.

    PubMed

    Tu, Li-Chun; Fu, Guo; Zilman, Anton; Musser, Siegfried M

    2013-12-11

    Nuclear pore complexes (NPCs) mediate cargo traffic between the nucleus and the cytoplasm of eukaryotic cells. Nuclear transport receptors (NTRs) carry cargos through NPCs by transiently binding to phenylalanine-glycine (FG) repeats on intrinsically disordered polypeptides decorating the NPCs. Major impediments to understand the transport mechanism are the thousands of FG binding sites on each NPC, whose spatial distribution is unknown, and multiple binding sites per NTR, which leads to multivalent interactions. Using single molecule fluorescence microscopy, we show that multiple NTR molecules are required for efficient transport of a large cargo, while a single NTR promotes binding to the NPC but not transport. Particle trajectories and theoretical modelling reveal a crucial role for multivalent NTR interactions with the FG network and indicate a non-uniform FG repeat distribution. A quantitative model is developed wherein the cytoplasmic side of the pore is characterized by a low effective concentration of free FG repeats and a weak FG-NTR affinity, and the centrally located dense permeability barrier is overcome by multivalent interactions, which provide the affinity necessary to permeate the barrier.

  20. Space-charge limited transport in large-area monolayer hexagonal boron nitride.

    PubMed

    Mahvash, Farzaneh; Paradis, Etienne; Drouin, Dominique; Szkopek, Thomas; Siaj, Mohamed

    2015-04-08

    Hexagonal boron nitride (hBN) is a wide-gap material that has attracted significant attention as an ideal dielectric substrate for 2D crystal heterostructures. We report here the first observation of in-plane charge transport in large-area monolayer hBN, grown by chemical vapor deposition. The quadratic scaling of current with voltage at high bias corresponds to a space-charge limited conduction mechanism, with a room-temperature mobility reaching up to 0.01 cm(2)/(V s) at electric fields up to 100 kV/cm in the absence of dielectric breakdown. The observation of in-plane charge transport highlights the semiconducting nature of monolayer hBN, and identifies hBN as a wide-gap 2D crystal capable of supporting charge transport at high field. Future exploration of charge transport in hBN is motivated by the fundamental study of UV optoelectronics and the massive Dirac fermion spectrum of hBN.

  1. Second-order subsonic airfoil theory including edge effects

    NASA Technical Reports Server (NTRS)

    Van Dyke, Milton D

    1956-01-01

    Several recent advances in plane subsonic flow theory are combined into a unified second-order theory for airfoil sections of arbitrary shape. The solution is reached in three steps: the incompressible result is found by integration, it is converted into the corresponding subsonic compressible result by means of the second-order compressibility rule, and it is rendered uniformly valid near stagnation points by further rules. Solutions for a number of airfoils are given and are compared with the results of other theories and of experiment. A straight-forward computing scheme is outlined for calculating the surface velocities and pressures on any airfoil at any angle of attack

  2. Subsonic flow over thin oblique airfoils at zero lift

    NASA Technical Reports Server (NTRS)

    Jones, Robert T

    1948-01-01

    A previous report gave calculations for the pressure distribution over thin oblique airfoils at supersonic speed. The present report extends the calculations to subsonic speeds. It is found that the flows again can be obtained by the superposition of elementary conical flow fields. In the case of the swept-back wing the pressure distributions remain qualitatively similar at subsonic and supersonic speeds. Thus a distribution similar to the Ackeret type of distribution appears on the root sections of the swept-back wing at Mach=0. The resulting positive pressure drag on the root section is balanced by negative drags on outboard sections.

  3. The VIBRA-8 Subsonic Aerodynamic Nuclear Gust Vulnerability Code.

    DTIC Science & Technology

    1979-05-01

    entries along with AA(a=O, M) as given by Eq. (12) to obtain f NP(s-*). Data for the symmetric 64A006 and 64A010 airfoils (6 and 10 percent thick...N.A.C.A. Report 1977, 1952. 5. Stivers, L.S., Jr., Effects of Subsonic Mach Number on the Forces and Pressure Distributions on Four NACA 64A-Series...Airfoil Sections at Angles of Attack as High as 280, NACA TN3162, March 1954. 6. Axelson, J.A., and Haacker, J.F., Subsonic Wing Loadings on a 450 Sweptback

  4. Defective nuclear import of Tpr in Progeria reflects the Ran sensitivity of large cargo transport

    PubMed Central

    Snow, Chelsi J.; Dar, Ashraf; Dutta, Anindya; Kehlenbach, Ralph H.

    2013-01-01

    The RanGTPase acts as a master regulator of nucleocytoplasmic transport by controlling assembly and disassembly of nuclear transport complexes. RanGTP is required in the nucleus to release nuclear localization signal (NLS)–containing cargo from import receptors, and, under steady-state conditions, Ran is highly concentrated in the nucleus. We previously showed the nuclear/cytoplasmic Ran distribution is disrupted in Hutchinson-Gilford Progeria syndrome (HGPS) fibroblasts that express the Progerin form of lamin A, causing a major defect in nuclear import of the protein, translocated promoter region (Tpr). In this paper, we show that Tpr import was mediated by the most abundant import receptor, KPNA2, which binds the bipartite NLS in Tpr with nanomolar affinity. Analyses including NLS swapping revealed Progerin did not cause global inhibition of nuclear import. Rather, Progerin inhibited Tpr import because transport of large protein cargoes was sensitive to changes in the Ran nuclear/cytoplasmic distribution that occurred in HGPS. We propose that defective import of large protein complexes with important roles in nuclear function may contribute to disease-associated phenotypes in Progeria. PMID:23649804

  5. Defective nuclear import of Tpr in Progeria reflects the Ran sensitivity of large cargo transport.

    PubMed

    Snow, Chelsi J; Dar, Ashraf; Dutta, Anindya; Kehlenbach, Ralph H; Paschal, Bryce M

    2013-05-13

    The RanGTPase acts as a master regulator of nucleocytoplasmic transport by controlling assembly and disassembly of nuclear transport complexes. RanGTP is required in the nucleus to release nuclear localization signal (NLS)-containing cargo from import receptors, and, under steady-state conditions, Ran is highly concentrated in the nucleus. We previously showed the nuclear/cytoplasmic Ran distribution is disrupted in Hutchinson-Gilford Progeria syndrome (HGPS) fibroblasts that express the Progerin form of lamin A, causing a major defect in nuclear import of the protein, translocated promoter region (Tpr). In this paper, we show that Tpr import was mediated by the most abundant import receptor, KPNA2, which binds the bipartite NLS in Tpr with nanomolar affinity. Analyses including NLS swapping revealed Progerin did not cause global inhibition of nuclear import. Rather, Progerin inhibited Tpr import because transport of large protein cargoes was sensitive to changes in the Ran nuclear/cytoplasmic distribution that occurred in HGPS. We propose that defective import of large protein complexes with important roles in nuclear function may contribute to disease-associated phenotypes in Progeria.

  6. Simulation and Parameterization of the Turbulent Transport in the Hurricane Boundary Layer by Large Eddies

    NASA Astrophysics Data System (ADS)

    Zhu, P.

    2008-05-01

    Hurricane boundary layer (HBL) processes, especially, the structure of the coherent large eddy circulations (LECs) and their induced vertical transport, are not well understood. This paper introduces a large eddy simulation (LES) framework in a weather hindcasting mode developed from a multiple scale nested Weather Research & Forecasting (WRF) model. Using the WRF-LES, this study investigated the structure of the HBL LECs and the associated vertical transport during the landfall of Hurricane Ivan (2004). The simulation shows that the HBL LECs exist in a mean stable environment and consist of well defined updraft and downdraft. Statistically, the HBL LECs are only slightly skewed with the updrafts and downdrafts relatively evenly distributed spatially. The inversion base basically envelopes the upper boundary of LECs. The trough in between two adjacent LECs is where most entrainment takes place, whereas the crest of the LECs is where boundary layer air detrains out of the HBL. In such a way, LECs directly connect the surface, the HBL, and the main body of a hurricane vortex and enhance the exchange of energy, moisture, and momentum between them. It is found that the current boundary layer schemes significantly under-estimate the resolved turbulent fluxes due to the fact that the effects of LECs have not been included in the parameterizations. Based on the statistical structure of LECs simulated by the WRF-LES, this paper proposes a conceptual updraft-downdraft model that can potentially be implemented in weather forecasting models to parameterize the fluxes induced by the HBL LEC transport.

  7. Large Area Applications and Current Transport Considerations in Carbon Nanotube Composites

    NASA Astrophysics Data System (ADS)

    Carey, David; Connolly, Thomas; Smith, Richard; Luke, Matt

    2010-03-01

    Carbon nanotube (CNT) electronics can be broadly split into to single or few CNT-based architectures, such as that found in a transistor, or multiple nanotube based architectures such as in films or composites. Potential large area applications of the later include transparent electronics, nanocomposites for displays or lighting or in sensor technology. Crucial to the development of these applications is an understanding of the factors that control the current transport. In particular a key question to be asked is `what is the rate limiting step for electron transport?' We have studied the field induced electron emission with low volume fractions of CNTs in PVA. We find that excellent emission can be found with as low as 1 vol. % CNTs - one of the lowest values reported for a nanocomposite cathode [1]. Below this concentration we find the rate limiting step for emission to be controlled by transport through the composite. We generalize our conclusions for other large area CNT based applications such as transparent electronics and next generation technologies. [1] Thomas Connolly, Richard C. Smith, Yenny Hernandez, Yurii Gun'ko, Jonathan N. Coleman and J. David Carey, Small 5, 826 (2009).

  8. Space transportation alternatives for large space programs: The International Space University Summer Session, 1992

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan A.

    1993-01-01

    In 1992, the International Space University (ISU) held its Summer Session in Kitakyushu, Japan. This paper summarizes and expands upon some aspects of space solar power and space transportation that were considered during that session. The issues discussed in this paper are the result of a 10-week study by the Space Solar Power Program design project members and the Space Transportation Group to investigate new paradigms in space propulsion and how those paradigms might reduce the costs for large space programs. The program plan was to place a series of power satellites in Earth orbit. Several designs were studied where many kW, MW, or GW of power would be transmitted to Earth or to other spacecraft in orbit. During the summer session, a space solar power system was also detailed and analyzed. A high-cost space transportation program is potentially the most crippling barrier to such a space power program. At ISU, the focus of the study was to foster and develop some of the new paradigms that may eliminate the barriers to low cost for space exploration and exploitation. Many international and technical aspects of a large multinational program were studied. Environmental safety, space construction and maintenance, legal and policy issues of frequency allocation, technology transfer and control and many other areas were addressed. Over 120 students from 29 countries participated in this summer session. The results discussed in this paper, therefore, represent the efforts of many nations.

  9. Studies of dust transport in long pulse plasma discharges in the large helical device

    NASA Astrophysics Data System (ADS)

    Shoji, M.; Kasahara, H.; Tokitani, M.; Seki, T.; Saito, K.; Kamio, S.; Seki, R.; Tanaka, Y.; Pigarov, A.; Smirnov, R.; Kawamura, G.; Tanaka, H.; Masuzaki, S.; Uesugi, Y.; Mutoh, T.; The LHD Experiment Group

    2015-05-01

    Three-dimensional trajectories of incandescent dust particles in plasmas were observed with stereoscopic fast framing cameras in a large helical device. It proved that the dust is located in the peripheral plasma and most of the dust moves along the magnetic field lines with acceleration in the direction that corresponds to the plasma flow. ICRF heated long pulse plasma discharges were terminated with the release of large amounts of dust from a closed divertor region. After the experimental campaign, the traces of exfoliation of carbon rich mixed-material deposition layers were found in the divertor region. Transport of carbon dust is investigated using a modified dust transport simulation code, which can explain the observed dust trajectories. It also shows that controlling the radius of the dust particles to less than 1 mm is necessary to prevent the plasma termination by penetration of dust for the long pulse discharges. Dust transport simulation including heavy metal dust particles demonstrates that high heating power operation is effective for shielding the main plasma from dust penetration by an enhanced plasma flow effect and a high heat load onto the dust particles in the peripheral plasma. It shows a more powerful penetration characteristic of tungsten dust particles compared to that of carbon and iron dust particles.

  10. The large volume radiometric calorimeter system: A transportable device to measure scrap category plutonium

    SciTech Connect

    Duff, M.F.; Wetzel, J.R.; Breakall, K.L.; Lemming, J.F.

    1987-01-01

    An innovative design concept has been used to design a large volume calorimeter system. The new design permits two measuring cells to fit in a compact, nonevaporative environmental bath. The system is mounted on a cart for transportability. Samples in the power range of 0.50 to 12.0 W can be measured. The calorimeters will receive samples as large as 22.0 cm in diameter by 43.2 cm high, and smaller samples can be measured without lengthening measurement time or increasing measurement error by using specially designed sleeve adapters. This paper describes the design considerations, construction, theory, applications, and performance of the large volume calorimeter system. 2 refs., 5 figs., 1 tab.

  11. A Two-Stage Approach for Medical Supplies Intermodal Transportation in Large-Scale Disaster Responses

    PubMed Central

    Ruan, Junhu; Wang, Xuping; Shi, Yan

    2014-01-01

    We present a two-stage approach for the “helicopters and vehicles” intermodal transportation of medical supplies in large-scale disaster responses. In the first stage, a fuzzy-based method and its heuristic algorithm are developed to select the locations of temporary distribution centers (TDCs) and assign medial aid points (MAPs) to each TDC. In the second stage, an integer-programming model is developed to determine the delivery routes. Numerical experiments verified the effectiveness of the approach, and observed several findings: (i) More TDCs often increase the efficiency and utility of medical supplies; (ii) It is not definitely true that vehicles should load more and more medical supplies in emergency responses; (iii) The more contrasting the traveling speeds of helicopters and vehicles are, the more advantageous the intermodal transportation is. PMID:25350005

  12. A two-stage approach for medical supplies intermodal transportation in large-scale disaster responses.

    PubMed

    Ruan, Junhu; Wang, Xuping; Shi, Yan

    2014-10-27

    We present a two-stage approach for the "helicopters and vehicles" intermodal transportation of medical supplies in large-scale disaster responses. In the first stage, a fuzzy-based method and its heuristic algorithm are developed to select the locations of temporary distribution centers (TDCs) and assign medial aid points (MAPs) to each TDC. In the second stage, an integer-programming model is developed to determine the delivery routes. Numerical experiments verified the effectiveness of the approach, and observed several findings: (i) More TDCs often increase the efficiency and utility of medical supplies; (ii) It is not definitely true that vehicles should load more and more medical supplies in emergency responses; (iii) The more contrasting the traveling speeds of helicopters and vehicles are, the more advantageous the intermodal transportation is.

  13. Large scale reactive transport of nitrate across the surface water divide

    NASA Astrophysics Data System (ADS)

    Kortunov, E.; Lu, C.; Amos, R.; Grathwohl, P.

    2016-12-01

    Groundwater pollution caused by agricultural and atmospheric inputs is a pressing issue in environmental management worldwide. Various researchers have studied different aspects of nitrate contamination since the substantial increase of the agriculture pollution in the second half of the 20th century. This study addresses large scale reactive solute transport in a typical Germany hilly landscapes in a transect crossing 2 valleys: River Neckar and Ammer. The numerical model was constructed compromising a 2-D cross-section accounting for typical fractured mudstones and unconsolidated sediments. Flow modelling showed that the groundwater divide significantly deviates from the surface water divide providing conditions for inter-valley flow and transport. Reactive transport modelling of redox-sensitive solutes (e.g. agriculture nitrate and natural sulfate, DOC, ammonium) with MIN3P was used to elucidate source of nitrate in aquifers and rivers. Since both floodplains, in the Ammer and Neckar valley contain Holocene sediments relatively high in organic carbon, agricultural nitrate is reduced therein and does not reach the groundwater. However, nitrate applied in the hillslopes underlain by fractured oxidized mudrock is transported to the high yield sand and gravel aquifer in the Neckar valley. Therefore, the model predicts that nitrate in the Neckar valley comes, to a large extent, from the neighboring Ammer valley. Moreover, nitrate observed in the rivers and drains in the Ammer valley is very likely geogenic since frequent peat layers there release ammonium which is oxidized as it enters the surface water. Such findings are relevant for land and water quality management.

  14. An Investigation of Landing-Contact Conditions for a Large Turbojet Transport During Routine Daylight Operations

    NASA Technical Reports Server (NTRS)

    Stickle, Joseph W.; Silsby, Norman S.

    1960-01-01

    An investigation has been made by the NASA to obtain statistical measurements of landing-contact conditions for a large turbojet transport in commercial airline operations. The investigation was conducted at the Los Angeles International Airport in Los Angeles, California. Measurements were taken photographically during routine daylight operations. The quantities determined were vertical velocity, horizontal velocity, rolling velocity, bank angle, and distance from runway threshold, just prior to ground contact. The results indicated that the mean vertical velocity for the turbojet-transport landings was 1.62 feet per second and that 1 landing out of 100 would be expected to equal or exceed about 4.0 feet per second. The mean airspeed at contact was 132.0 knots, with 1 landing in 100 likely to equal or exceed about 153.0 knots. The mean rolling velocity was about 1.6 deg per second. One lending in 100 would probably equal or exceed a rolling velocity of about 4.0 deg. per second in the direction of the first wheel to touch. The mean bank angle for the turbojet transports was 1.04 deg, and right and left angles of bank were about evenly divided. One lending in 100 would be likely to equal or exceed a bank angle of about 3.5 deg. The mean value of distance to touchdown from the runway threshold was 1,560 feet. One lending in 100 would be expected to touchdown at or beyond about 2,700 feet from the runway threshold. The mean values for vertical velocity, airspeed, and distance t o touch-down for the turbojet transports were somewhat higher than those found previously for piston-engine transports. No significant differences were found for values of rolling velocity and bank angle.

  15. Platelet serotonin transporter (5HTt): physiological influences on kinetic characteristics in a large human population.

    PubMed

    Banović, Miroslav; Bordukalo-Niksić, Tatjana; Balija, Melita; Cicin-Sain, Lipa; Jernej, Branimir

    2010-01-01

    The present study had two goals: first, to give a detailed description of a reliable method for full kinetic analysis of serotonin transporter (5HTt) on the membrane of human platelets, and second, as a main issue, to report on physiological influences on kinetic characteristics of this transmembrane transport on a large population of healthy individuals. Full kinetic analyses of platelet serotonin uptake were performed on 334 blood donors of both sexes by the use of 14C-radioisotopic method, which was first optimized according to assumptions of enzyme kinetic analyses, with regard to platelet concentration, duration of uptake, concentration of substrate as well as important technical parameters (underpressure of filtration, blanks, incubating temperature, etc). Kinetic parameters of platelet serotonin uptake in the whole population were for V(max): 142 +/- 25.3 pmol 5HT/10(8) platelets/minute and for K(m): 0.404 +/- 0.089 microM 5HT. Besides the report on kinetic values of 5HT transporter protein, we have also described major physiological influences on the mentioned parameters, V(max), K(m) and their derivative, V(max)/K(m) (transporter efficiency): range and frequency distribution of normal values, intraindividual stability over time, lack of age influence, gender dependence and seasonal variations. The report on kinetic values and main physiological influences on platelet serotonin transport kinetics, obtained by the use of thoroughly reassessed methodology, and on by far the largest human population studied until now, offers a reliable frame of reference for pathophysiological studies of this parameter in various clinical fields.

  16. Airflow Dynamics and Sand Transport over a Coastal Foredune with Large Woody Debris.

    NASA Astrophysics Data System (ADS)

    Grilliot, M. J.; Walker, I. J.; Bauer, B. O.

    2016-12-01

    Airflow dynamics and sand transport patterns over beach-foredune systems are complex due to the effects of topographic forcing and varied surface roughness elements. The role of large woody debris (LWD) as a roughness element in foredune dynamics is understudied compared to the effects of plant cover. Unlike plants, non-porous objects like LWD impose bluff body effects and induce secondary flow circulation that varies with LWD size, density, and arrangement. It is hypothesized that modified flow patterns over LWD can influence beach-dune sediment budgets and dune geometry via changes to mean near-surface flow patterns, turbulence, sand transport pathways and sedimentation patterns. In turn, LWD may act as an accretion anchor and store appreciable amounts of aeolian sand that subsequently may provide an enhanced buffer against coastal and/or wind erosion. This study examines turbulent airflow dynamics and related sand transport patterns for oblique onshore flow conditions over a mesotidal beach and scarped dune on Calvert Island, British Columbia, Canada. Abundant exposed LWD fronting the foredune enhances turbulent Reynolds stress (RS) and turbulence intensity (TI) near the surface. During low, yet competent wind speeds (6.54 m s-1), RS and TI are not competent enough in the sheltered flow regions within the LWD matrix and sediment deposition occurs. However, small zones of localized acceleration were observed with sand transport. Higher wind speeds, well above the entrainment threshold, increase RS and TI over LWD relative to the beach, facilitating sediment transport through and over the LWD matrix, with localized pockets of deposition in sheltered areas. The majority of LWD deposits on beaches in the region are anthropogenic logging debris and are known to be decreasing since the 1950s, but likely earlier. Thus, it is important to understand how non-porous roughness elements, like LWD, affect beach-dune sediment budgets and evolution, particularly in light of

  17. Modeling scalar dissipation and scalar variance in large eddy simulation: Algebraic and transport equation closures

    NASA Astrophysics Data System (ADS)

    Knudsen, E.; Richardson, E. S.; Doran, E. M.; Pitsch, H.; Chen, J. H.

    2012-05-01

    Scalar dissipation rates and subfilter scalar variances are important modeling parameters in large eddy simulations (LES) of reacting flows. Currently available models capture the general behavior of these parameters, but these models do not always perform with the degree of accuracy that is needed for predictive LES. Here, two direct numerical simulations (DNS) are used to analyze LES dissipation rate and variance models, and to propose a new model for the dissipation rate that is based on a transport equation. The first DNS that is considered is a non-premixed auto-igniting C2H4 jet flame simulation originally performed by Yoo et al. [Proc. Combust. Inst. 33, 1619-1627 (2011)], 10.1016/j.proci.2010.06.147. A LES of this case is run using algebraic models for the dissipation rate and subfilter variance. It is shown that the algebraic models fail to adequately reproduce the DNS results. This motivates the introduction of a transport equation model for the LES dissipation rate. Closure of the equation is addressed by formulating a new adapted dynamic approach. This approach borrows dynamically computed information from LES quantities that, unlike the dissipation rate, do not reside on the smallest flow length scales. The adapted dynamic approach is analyzed by considering a second DNS of scalar mixing in homogeneous isotropic turbulence. Data from this second DNS are used to confirm that the adapted dynamic approach successfully closes the dissipation rate equation over a wide range of LES filter widths. The first reacting jet case is then returned to and used to test the LES transport equation models. The transport equation model for the dissipation rate is shown to be more accurate than its algebraic counterpoint, and the dissipation rate is eliminated as a source of error in the transported variance model.

  18. Large-volume lateral magma transport from the Mull volcano: An insight to magma chamber processes

    NASA Astrophysics Data System (ADS)

    Ishizuka, Osamu; Taylor, Rex N.; Geshi, Nobuo; Mochizuki, Nobutatsu

    2017-04-01

    Long-distance lateral magma transport within the crust has been inferred for various magmatic systems including oceanic island volcanoes, mid-oceanic ridges, and large igneous provinces. However, studying the physical and chemical properties of active fissure systems is difficult. Hence, this study investigates the movement of magma away from the Mull volcano in the North Atlantic Igneous Province, where erosion has exposed its upper crustal dike networks. Magmatic lineations within dikes indicate that the magma flow in the Mull dike suite changed from near vertical to horizontal within 30 km of the volcanic center. This implies that distal dikes were fed by lateral magma transport from Mull. Geochemical characteristics indicate that many <50 km long dikes have deep crustal signatures, reflecting storage and assimilation in Lewisian basement. Following crystallization and assimilation in the lower crust, magma fed an upper crustal reservoir, where further fractionation and incorporation of Moinian rocks generated felsic compositions. Distal dikes are andesitic and reflect events in which large volumes of mafic and felsic magma were combined by mixing between lower and upper crustal reservoirs to generate the 30-80 km3 required to supply the long-distance dikes. Once propagated, compositions along dikes were not significantly affected by assimilation and crystallization. Supplying the distal dikes with magma would have required a large-scale evacuation of the crustal reservoirs that acted as a potential trigger for explosive volcanism and the caldera formation recorded in Mull central complex.

  19. Spatial domain-based parallelism in large scale, participating-media, radiative transport applications

    SciTech Connect

    Burns, S.P.; Christon, M.A.

    1996-11-01

    Parallelism for gray participating media radiation heat transfer may be placed in two primary categories: spatial and angular domain-based parallelism. Angular, e.g., ray based, decomposition has received the greatest attention in the open literature for moderate sized applications where the entire geometry may be placed on processor. Angular based decomposition is limited, however, for large scale applications (O(10{sup 6}) to O(10{sup 8}) computational cells) given the memory required to store computational grids of this size on each processor. Therefore, the objective of this work is to examine the application of spatial domain-based parallelism to large scale, three-dimensional, participating-media radiation transport calculations using a massively parallel supercomputer architecture. Both scaled and fixed problem size efficiencies are presented for an application of the Discrete Ordinate method to a three dimensional, non-scattering radiative transport application with nonuniform absorptivity. The data presented shows that the spatial domain-based decomposition paradigm results in some degradation in the parallel efficiency but provides useful speedup for large computational grids.

  20. Large wood transport and jam formation in a series of flume experiments

    NASA Astrophysics Data System (ADS)

    Davidson, S. L.; MacKenzie, L. G.; Eaton, B. C.

    2015-12-01

    Large wood has historically been removed from streams, resulting in the depletion of in-stream wood in waterways worldwide. As wood increases morphological and hydraulic complexity, the addition of large wood is commonly employed as a means to rehabilitate in-stream habitat. At present, however, the scientific understanding of wood mobilization and transport is incomplete. This paper presents results from a series of four flume experiments in which wood was added to a reach to investigate the piece and reach characteristics that determine wood stability and transport, as well as the time scale required for newly recruited wood to self-organize into stable jams. Our results show that wood transitions from a randomly distributed newly recruited state to a self-organized, or jam-stabilized state, over the course of a single bankfull flow event. Statistical analyses of piece mobility during this transitional period indicate that piece irregularities, especially rootwads, dictate the stability of individual wood pieces; rootwad presence or absence accounts for up to 80% of the variance explained by linear regression models for transport distance. Furthermore, small pieces containing rootwads are especially stable. Large ramped pieces provide nuclei for the formation of persistent wood jams, and the frequency of these pieces in the reach impacts the travel distance of mobile wood. This research shows that the simulation of realistic wood dynamics is possible using a simplified physical model, and also has management implications, as it suggests that randomly added wood may organize into persistent, stable jams, and characterizes the time scale for this transition.

  1. Computational Investigations of Noise Suppression in Subsonic Round Jets

    NASA Technical Reports Server (NTRS)

    Pruett, C. David

    1997-01-01

    NASA Grant NAG1-1802, originally submitted in June 1996 as a two-year proposal, was awarded one-year's funding by NASA LaRC for the period 5 Oct., 1996, through 4 Oct., 1997. Because of the inavailability (from IT at NASA ARC) of sufficient supercomputer time in fiscal 1998 to complete the computational goals of the second year of the original proposal (estimated to be at least 400 Cray C-90 CPU hours), those goals have been appropriately amended, and a new proposal has been submitted to LaRC as a follow-on to NAG1-1802. The current report documents the activities and accomplishments on NAG1-1802 during the one-year period from 5 Oct., 1996, through 4 Oct., 1997. NASA Grant NAG1-1802, and its predecessor, NAG1-1772, have been directed toward adapting the numerical tool of Large-Eddy Simulation (LES) to aeroacoustic applications, with particular focus on noise suppression in subsonic round jets. In LES, the filtered Navier-Stokes equations are solved numerically on a relatively coarse computational grid. Residual stresses, generated by scales of motion too small to be resolved on the coarse grid, are modeled. Although most LES incorporate spatial filtering, time-domain filtering affords certain conceptual and computational advantages, particularly for aeroacoustic applications. Consequently, this work has focused on the development of SubGrid-Scale (SGS) models that incorporate time- domain filters. The author is unaware of any previous attempt at purely time-filtered LES; however, Aldama and Dakhoul and Bedford have considered approaches that combine both spatial and temporal filtering. In our view, filtering in both space and time is redundant, because removal of high frequencies effects the removal of small spatial scales and vice versa.

  2. Materials Science and Materials Chemistry for Large Scale Electrochemical Energy Storage: From Transportation to Electrical Grid

    SciTech Connect

    Liu, Jun; Zhang, Jiguang; Yang, Zhenguo; Lemmon, John P.; Imhoff, Carl H.; Graff, Gordon L.; Li, Liyu; Hu, Jian Z.; Wang, Chong M.; Xiao, Jie; Xia, Guanguang; Viswanathan, Vilayanur V.; Baskaran, Suresh; Sprenkle, Vincent L.; Li, Xiaolin; Shao, Yuyan; Schwenzer, Birgit

    2013-02-15

    Large-scale electrical energy storage has become more important than ever for reducing fossil energy consumption in transportation and for the widespread deployment of intermittent renewable energy in electric grid. However, significant challenges exist for its applications. Here, the status and challenges are reviewed from the perspective of materials science and materials chemistry in electrochemical energy storage technologies, such as Li-ion batteries, sodium (sulfur and metal halide) batteries, Pb-acid battery, redox flow batteries, and supercapacitors. Perspectives and approaches are introduced for emerging battery designs and new chemistry combinations to reduce the cost of energy storage devices.

  3. Design procedure for low-drag subsonic airfoils

    NASA Technical Reports Server (NTRS)

    Peterson, J. B.; Chen, A. B.

    1975-01-01

    Airfoil has least amount of drag under given restrictions of boundary layer transition position, lift coefficient, thickness ratio, and Reynolds number based on airfoil chord. It is suitable for use as wing and propeller aircraft sections operating at subsonic speeds and for hydrofoil sections and blades for fans, compressors, turbines, and windmills.

  4. Subsonic annular wing theory with application to flow about nacelles

    NASA Technical Reports Server (NTRS)

    Mann, M. J.

    1974-01-01

    A method has recently been developed for calculating the flow over a subsonic nacelle at zero angle of attack. The method makes use of annular wing theory and boundary-layer theory and has shown good agreement with both experimental data and more complex theoretical solutions. The method permits variation of the mass flow by changing the size of a center body.

  5. Near-Field Noise Computation for a Subsonic Coannular Jet

    NASA Technical Reports Server (NTRS)

    Loh, Ching Y.; Hultgren, Lennart S.; Jorgenson, Philip C. E.

    2008-01-01

    A high-Reynolds-number, subsonic coannular jet is simulated, using a three-dimensional finite-volume LES method, with emphasis on the near field noise. The nozzle geometry used is the NASA Glenn 3BB baseline model. The numerical results are generally in good agreement with existing experimental findings.

  6. SPHYNX: SPH hydrocode for subsonic hydrodynamical instabilities and strong shocks

    NASA Astrophysics Data System (ADS)

    Cabezon, Ruben M.; Garcia-Senz, Domingo

    2017-09-01

    SPHYNX addresses subsonic hydrodynamical instabilities and strong shocks; it is Newtonian, grounded on the Euler-Lagrange formulation of the smoothed-particle hydrodynamics technique, and density based. SPHYNX uses an integral approach for estimating gradients, a flexible family of interpolators to suppress pairing instability, and incorporates volume elements to provides better partition of the unity.

  7. 27. VIEW OF EXHAUST AND DEFLECTOR FOR SUBSONIC AERODYNAMICS RESEARCH ...

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

    27. VIEW OF EXHAUST AND DEFLECTOR FOR SUBSONIC AERODYNAMICS RESEARCH LABORATORY, BUILDING 25C, WHICH REPLACED THE 10-FOOT WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  8. 28. VIEW OF EXHAUST AND DEFLECTOR FOR SUBSONIC AERODYNAMICS RESEARCH ...

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

    28. VIEW OF EXHAUST AND DEFLECTOR FOR SUBSONIC AERODYNAMICS RESEARCH LABORATORY, BUILDING 25C, WHICH REPLACED THE 10-FOOT WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  9. 26. VIEW OF EXHAUST AND DEFLECTOR FOR SUBSONIC AERODYNAMICS RESEARCH ...

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

    26. VIEW OF EXHAUST AND DEFLECTOR FOR SUBSONIC AERODYNAMICS RESEARCH LABORATORY, BUILDING 25C, WHICH REPLACED THE 10-FOOT WIND TUNNEL (1991). - Wright-Patterson Air Force Base, Area B, Buildings 25 & 24,10-foot & 20-foot Wind Tunnel Complex, Northeast side of block bounded by K, G, Third, & Fifth Streets, Dayton, Montgomery County, OH

  10. Wing-Design Program for Subsonic or Supersonic Speeds

    NASA Technical Reports Server (NTRS)

    Carlson, H. W.; Walkley, K. B.

    1986-01-01

    Surface of mildest possible camber generated. WINGDES provides analysis, design capability and is applicable to both subsonic and supersonic flows. Optimization carried out for entire wing or for designated leading- and trailing-edge areas, for design of missionadaptive surfaces. WINGDES written in FORTRAN IV.

  11. Subsonic maneuver capability of a supersonic cruise fighter wing concept

    NASA Technical Reports Server (NTRS)

    Riebe, Gregory D.; Fox, Charles H., Jr.

    1987-01-01

    A theoretical and experimental investigation was conducted of the subsonic maneuver capability of a fighter wing concept designed for supersonic cruise. To improve the subsonic maneuver capability, the wing utilized full-span leading- and trailing-edge flaps that were designed with the aid of a subsonic-analysis computer program. Wind-tunnel tests were made at Mach numbers of 0.3, 0.5, and 0.7. Force and moment data obtained were compared with theoretical predictions of Mach 0.5 from two subsonic-analysis computer programs. The two theoretical programs gave a good prediction of the lift and drag characteristics but only a fair prediction of the pitching moment. The experimental results of this study show that with the proper combination of leading- and trailing-edge flap deflections, a suction parameter of nearly 90 percent can be attained at a Mach number of 0.5 and a lift coefficient of 0.73; this is a three-fold improvement from 30 percent for the basic wing.

  12. Tracer Transport by Deep Convection: Implications of the Connection Between Convective Mass Fluxes and Large-Scale Circulations

    NASA Astrophysics Data System (ADS)

    Lawrence, M. G.; Salzmann, M.; Tost, H.; Joeckel, P.; Lelieveld, J.

    2007-12-01

    Global chemistry-transport models (CTMs) generally simulate vertical tracer transport by deep convection separately from the advective transport due to large-scale mean winds, even though a component of the large-scale transport, for instance in the Hadley and Walker cells, occurs in deep convective updrafts. This split treatment of vertical transport can have several significant implications for CTM simulations, such as numerical diffusion, misinterpretation of the transport characteristics in convectively active regions, and underestimation of the effects of convective tracer transport on ozone and other gases. Here we show that there is a significant overlap between the convective and large-scale advective vertical transport fluxes in the CTM MATCH, and discuss the main implications for tracer transport studies which can be expected due to this. We also give an outlook to the next step of this study, in which we are examining the connection between diagnosed convective mass fluxes and the vertical fluxes in the tropical Hadley and Walker Cells using the ECHAM5/MESSy GCM, which is set up with a flexible framework allowing the use of several different convection parameterizations. From the direct comparison of multiple deep convection parameterizations within the same model we expect to gain a better sense of the relationship between parameterized deep convection and large-scale circulations, as well as of the present uncertainty due to differences in convection parameterizations. This work is anticipated to contribute to the objectives of Activity 2 (vertical tracer distributions) of AC&C.

  13. Advanced Low Emissions Subsonic Combustor Study

    NASA Technical Reports Server (NTRS)

    Smith, Reid

    1998-01-01

    Recent advances in commercial and military aircraft gas turbines have yielded significant improvements in fuel efficiency and thrust-to-weight ratio, due in large part to increased combustor operating pressures and temperatures. However, the higher operating conditions have increased the emission of oxides of nitrogen (NOx), which is a pollutant with adverse impact on the atmosphere and environment. Since commercial and military aircraft are the only important direct source of NOx emissions at high altitudes, there is a growing consensus that considerably more stringent limits on NOx emissions will be required in the future for all aircraft. In fact, the regulatory communities have recently agreed to reduce NOx limits by 20 percent from current requirements effective in 1996. Further reductions at low altitude, together with introduction of limits on NOx at altitude, are virtual certainties. In addition, the U.S. Government recently conducted hearings on the introduction of federal fees on the local emission of pollutants from all sources, including aircraft. While no action was taken regarding aircraft in this instance, the threat of future action clearly remains. In these times of intense and growing international competition, the U.S. le-ad in aerospace can only be maintained through a clear technological dominance that leads to a product line of maximum value to the global airline customer. Development of a very low NOx combustor will be essential to meet the future needs of both the commercial and military transport markets, if additional economic burdens and/or operational restrictions are to be avoided. In this report, Pratt & Whitney (P&W) presents the study results with the following specific objectives: Development of low-emissions combustor technologies for advances engines that will enter into service circa 2005, while producing a goal of 70 percent lower NOx emissions, compared to 1996 regulatory levels. Identification of solution approaches to

  14. Modeling reactive transport of reclaimed water through large soil columns with different low-permeability layers

    NASA Astrophysics Data System (ADS)

    Hu, Haizhu; Mao, Xiaomin; Barry, D. A.; Liu, Chengcheng; Li, Pengxiang

    2015-03-01

    The efficacy of different proportions of silt-loam/bentonite mixtures overlying a vadose zone in controlling solute leaching to groundwater was quantified. Laboratory experiments were carried out using three large soil columns, each packed with 200-cm-thick riverbed soil covered by a 2-cm-thick bentonite/silt-loam mixture as the low-permeability layer (with bentonite mass accounting for 12, 16 and 19 % of the total mass of the mixture). Reclaimed water containing ammonium (NH4 +), nitrate (NO3 -), organic matter (OM), various types of phosphorus and other inorganic salts was applied as inflow. A one-dimensional mobile-immobile multi-species reactive transport model was used to predict the preferential flow and transport of typical pollutants through the soil columns. The simulated results show that the model is able to predict the solute transport in such conditions. Increasing the amount of bentonite in the low-permeability layer improves the removal of NH4 + and total phosphorous (TP) because of the longer contact time and increased adsorption capacity. The removal of NH4 + and OM is mainly attributed to adsorption and biodegradation. The increase of TP and NO3 - concentration mainly results from discharge and nitrification in riverbed soils, respectively. This study underscores the role of low-permeability layers as barriers in groundwater protection. Neglect of fingers or preferential flow may cause underestimation of pollution risk.

  15. Large Eddy Simulation of Transient Flow, Solidification, and Particle Transport Processes in Continuous-Casting Mold

    NASA Astrophysics Data System (ADS)

    Liu, Zhongqiu; Li, Linmin; Li, Baokuan; Jiang, Maofa

    2014-07-01

    The current study developed a coupled computational model to simulate the transient fluid flow, solidification, and particle transport processes in a slab continuous-casting mold. Transient flow of molten steel in the mold is calculated using the large eddy simulation. An enthalpy-porosity approach is used for the analysis of solidification processes. The transport of bubble and non-metallic inclusion inside the liquid pool is calculated using the Lagrangian approach based on the transient flow field. A criterion of particle entrapment in the solidified shell is developed using the user-defined functions of FLUENT software (ANSYS, Inc., Canonsburg, PA). The predicted results of this model are compared with the measurements of the ultrasonic testing of the rolled steel plates and the water model experiments. The transient asymmetrical flow pattern inside the liquid pool exhibits quite satisfactory agreement with the corresponding measurements. The predicted complex instantaneous velocity field is composed of various small recirculation zones and multiple vortices. The transport of particles inside the liquid pool and the entrapment of particles in the solidified shell are not symmetric. The Magnus force can reduce the entrapment ratio of particles in the solidified shell, especially for smaller particles, but the effect is not obvious. The Marangoni force can play an important role in controlling the motion of particles, which increases the entrapment ratio of particles in the solidified shell obviously.

  16. Modification of turbulent transport with continuous variation of flow shear in the large plasma device.

    PubMed

    Schaffner, D A; Carter, T A; Rossi, G D; Guice, D S; Maggs, J E; Vincena, S; Friedman, B

    2012-09-28

    Continuous control over azimuthal flow and shear in the edge of the Large Plasma Device (LAPD) has been achieved using a biasable limiter which has allowed a careful study of the effect of flow shear on pressure-gradient-driven turbulence and transport in the LAPD. The LAPD rotates spontaneously in the ion diamagnetic direction; positive limiter bias first reduces, then minimizes (producing a near-zero shear state), and finally reverses the flow into the electron diamagnetic direction. Degradation of particle confinement is observed in the minimum shearing state and a reduction in the turbulent particle flux is observed with increasing shearing in both flow directions. Near-complete suppression of the turbulent particle flux is observed for shearing rates comparable to the turbulent autocorrelation rate measured in the minimum shear state. Turbulent flux suppression is dominated by amplitude reduction in low-frequency (<10 kHz) density fluctuations. An increase in fluctuations for the highest shearing states is observed with the emergence of a coherent mode which does not lead to net particle transport. The variations of density fluctuations are fit well with power laws and compare favorably to simple models of shear suppression of transport.

  17. Large eddy simulation study of scalar transport in fully developed wind-turbine array boundary layers

    NASA Astrophysics Data System (ADS)

    Calaf, Marc; Parlange, Marc B.; Meneveau, Charles

    2011-12-01

    Wind harvesting is fast becoming an important alternative source of energy. As wind farms become larger, they begin to attain scales at which two-way interactions with the atmospheric boundary layer (ABL) must be taken into account. Several studies have shown that there is a quantifiable effect of wind farms on the local meteorology, mainly through changes in the land-atmosphere fluxes of heat and moisture. In particular, the observed trends suggest that wind farms increase fluxes at the surface and this could be due to increased turbulence in the wakes. Conversely, simulations and laboratory experiments show that underneath wind farms, the friction velocity is decreased due to extraction of momentum by the wind turbines, a factor that could decrease scalar fluxes at the surface. In order to study this issue in more detail, a suite of large eddy simulations of an infinite (fully developed) wind turbine array boundary layer, including scalar transport from the ground surface without stratification, is performed. Results show an overall increase in the scalar fluxes of about 10%-15% when wind turbines are present in the ABL, and that the increase does not strongly depend upon wind farm loading as described by the turbines' thrust coefficient and the wind turbines spacings. A single-column analysis including scalar transport shows that the presence of wind farms can be expected to increase slightly the scalar transport from the bottom surface and that this slight increase is due to a delicate balance between two strong opposing trends.

  18. Measurement of fissile mass in large-size containers with a transportable linear accelerator

    NASA Astrophysics Data System (ADS)

    Romeyer Dherbey, Jacques; Lyoussi, A.; Buisson, A.

    1997-02-01

    The quantification of transuranic material (TRU) in waste packages is a common problem of countries working in the field of nuclear nondestructive inspection. The direct measurement of TRU mass inside large size closed containers is difficult due to several effects, mainly the matrix attenuation and uncertainty on the localization of the radioactive mass. The present document describes the method being developed to assay conditioned waste packages using a transportable linear accelerator which is called Mini- Linatron. The system uses a pulsed electron beam from the Mini-Linatron to produce high energy bremsstrahlung photon bursts from thin metallic converter. The transportable linear accelerator operates at 6, 9 and 11 MeV with a repetition rate between 10 to 300 Hz and a 4.5 microsecond(s) pulse duration. The maximum gamma dose rate is about 23 Gy/mn at 1 m. The photons induce fission in fissile and fertile nuclei. We counted delayed neutrons emitted after each pulse by using Sequential Photon Interrogation and Neutron Counting Signatures technique which has ben developed in this framework. Results of measurements on an experimental active gamma interrogation facility for embedded intermediate and low level wastes are presented. Finally, the advantages and performances of the photofission interrogation technique, the use of a transportable electron linear accelerator as a particle source, and the experimental and electronic details will be discussed.

  19. Optomechanical analysis of the flexure mounting configuration of large-aperture laser transport mirror

    NASA Astrophysics Data System (ADS)

    Zhang, Zheng; Quan, Xusong; Wang, Hui; Liu, Tianye; Xiong, Zhao; Yuan, Xiaodong; Rong, Yiming

    2017-02-01

    Motivated by the demand to minimize the mount-induced wavefront aberration of the large-aperture laser transport mirror, a low-stress flexure mounting configuration is proposed. Specific optomechanical analyses, including theoretical modeling, numerical analysis and field experiment, are presented. The mechanical properties of the flexure support were studied specifically. Besides, the relation between the mounting forces and the root-mean-square of the gradients (GRMS) value of the mirror surface is studied. Then, the appropriate value of the bolt preload is set to 500N, with which the GRMS value is just 5.35 nm/cm. The results indicate that the flexure mounting configuration is indeed a feasible and promising method to solve the mount-induced distortion problem of large-aperture optics.

  20. Optomechanical analysis of the mounting performance of large laser transport mirrors

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Cao, Tingfen; Xiong, Zhao; Yuan, Xiaodong; Yao, Chao; Zhang, Zheng; Ma, Guohui

    2015-03-01

    In the high-power laser facility (SG-III), focusing 48 laser beams into the target center better than 50 microns (RMS) within a few picoseconds is dependent on the stringent specifications of thousands of large optics and also puts huge challenges on the engineering characteristics of the design and mounting. A parametric optomechanical method is proposed to evaluate the performance of a 400 mm large-aperture transport mirror. With theoretical modeling and numerical analysis, the impacts of assembly structure, manufacturing errors, mounting loads, and gravity on the mirror surface aberrations are calculated and discussed in detail. With field experiments and case studies, the proposed method shows a powerful performance on the mirror surface aberrations' evaluation, and negative impacts of currently used mounting techniques for the mirror are found. Finally, a new assembly design is presented based on a discussion of its advantages.

  1. Transport equations for multicomponent anisotropic space plasmas - A review

    NASA Technical Reports Server (NTRS)

    Barakat, A. R.; Schunk, R. W.

    1982-01-01

    An attempt is made to present a unified approach to the study of transport phenomena in multicomponent anisotropic space plasmas. In particular, a system of generalized transport equations is presented that can be applied to widely different plasma flow conditions. The generalized transport equations can describe subsonic and supersonic flows, collision-dominated and collisionless flows, plasma flows in rapidly changing magnetic field configurations, multicomponent plasma flows with large temperature differences between the interacting species, and plasma flows that contain anisotropic temperature distributions. In addition, if Maxwell's equations of electricity and magnetism are added to the system of transport equations, they can be used to model electrostatic shocks, double layers, and magnetic merging processes. These transport equations also contain terms which act to regulate both the heat flow and temperature anisotropy, processes which appear to be operating in the solar wind.

  2. Multi-Mission Earth Vehicle Subsonic Dynamic Stability Testing and Analyses

    NASA Technical Reports Server (NTRS)

    Glaab, Louis J.; Fremaux, C. Michael

    2013-01-01

    Multi-Mission Earth Entry Vehicles (MMEEVs) are blunt-body vehicles designed with the purpose of transporting payloads from outer space to the surface of the Earth. To achieve high-reliability and minimum weight, MMEEVs avoid use of limited-reliability systems, such as parachutes, retro-rockets, and reaction control systems and rely on the natural aerodynamic stability of the vehicle throughout the Entry, Descent, and Landing (EDL) phase of flight. The Multi-Mission Systems Analysis for Planetary Entry (M-SAPE) parametric design tool is used to facilitate the design of MMEEVs for an array of missions and develop and visualize the trade space. Testing in NASA Langley?s Vertical Spin Tunnel (VST) was conducted to significantly improve M-SAPE?s subsonic aerodynamic models. Vehicle size and shape can be driven by entry flight path angle and speed, thermal protection system performance, terminal velocity limitations, payload mass and density, among other design parameters. The objectives of the VST testing were to define usable subsonic center of gravity limits, and aerodynamic parameters for 6-degree-of-freedom (6-DOF) simulations, for a range of MMEEV designs. The range of MMEEVs tested was from 1.8m down to 1.2m diameter. A backshell extender provided the ability to test a design with a much larger payload for the 1.2m MMEEV.

  3. 3D CFD modeling of subsonic and transonic flowing-gas DPALs with different pumping geometries

    NASA Astrophysics Data System (ADS)

    Yacoby, Eyal; Sadot, Oren; Barmashenko, Boris D.; Rosenwaks, Salman

    2015-10-01

    Three-dimensional computational fluid dynamics (3D CFD) modeling of subsonic (Mach number M ~ 0.2) and transonic (M ~ 0.9) diode pumped alkali lasers (DPALs), taking into account fluid dynamics and kinetic processes in the lasing medium is reported. The performance of these lasers is compared with that of supersonic (M ~ 2.7 for Cs and M ~ 2.4 for K) DPALs. The motivation for this study stems from the fact that subsonic and transonic DPALs require much simpler hardware than supersonic ones where supersonic nozzle, diffuser and high power mechanical pump (due to a drop in the gas total pressure in the nozzle) are required for continuous closed cycle operation. For Cs DPALs with 5 x 5 cm2 flow cross section pumped by large cross section (5 x 2 cm2) beam the maximum achievable power of supersonic devices is higher than that of the transonic and subsonic devices by only ~ 3% and ~ 10%, respectively. Thus in this case the supersonic operation mode has no substantial advantage over the transonic one. The main processes limiting the power of Cs supersonic DPALs are saturation of the D2 transition and large ~ 60% losses of alkali atoms due to ionization, whereas the influence of gas heating is negligible. For K transonic DPALs both the gas heating and ionization effects are shown to be unimportant. The maximum values of the power are higher than those in Cs transonic laser by ~ 11%. The power achieved in the supersonic and transonic K DPAL is higher than for the subsonic version, with the same resonator and K density at the inlet, by ~ 84% and ~ 27%, respectively, showing a considerable advantaged of the supersonic device over the transonic one. For pumping by rectangular beams of the same (5 x 2 cm2) cross section, comparison between end-pumping - where the laser beam and pump beam both propagate at along the same axis, and transverse-pumping - where they propagate perpendicularly to each other, shows that the output power and optical-to-optical efficiency are not

  4. Evaluation of the Transport of Natural Radioactive Materials in Large Lysimeters Using Hydrus-1D

    NASA Astrophysics Data System (ADS)

    Pontedeiro, E.; Cipriani, M.; van Genuchten, M.; Simunek, J.

    2007-12-01

    The mining industry in Brazil often uses raw materials that contain relatively high concentrations of naturally occurring radioactive materials (referred to as NORM). Ores of relatively low grade typically are used to produce refined metals of high purity (e.g., Nb, Ta, Sn, and Au) using pyrometallurgic processes. The final waste is a slag rich in natural radioactive contaminants (the U and Th decay series), which are then usually deposited in industrial landfills. To study the long-term fate and transport of radionuclides leached from the NORM wastes, several large (3 m deep) lysimeters were constructed at the Pocos de Caldas Laboratory of the Brazilian Nuclear Energy Commision (CNEN). The lysimeters were packed with surface soils and slags from one of the mining sites in South East Brazil. Main purpose of our lysimeter experiments was to follow the dissolution and transport of radionuclides from the slags under natural climatic conditions. Leaching rates and radionuclide concentrations of the effluent were observed during a three-year time period. A variety of physical and chemical properties of the soils and slags (including laboratory batch equilibrium sorption values) were also determined. The data were analyzed using several computer software packages, including the STANMOD code for analytical modeling of decay chain transport during steady flow, the HYDRUS-1D code for variably-saturated flow and the transport of multiple solutes, and the HP1 code for a more comprehensive analysis of the geochemistry involved. In this presentation we describe the experimental setup and provide preliminary results of the theoretical analyses, especially those using HYDRUS-1D.

  5. Biomass Energy for Transport and Electricity: Large scale utilization under low CO2 concentration scenarios

    SciTech Connect

    Luckow, Patrick; Wise, Marshall A.; Dooley, James J.; Kim, Son H.

    2010-01-25

    This paper examines the potential role of large scale, dedicated commercial biomass energy systems under global climate policies designed to stabilize atmospheric concentrations of CO2 at 400ppm and 450ppm. We use an integrated assessment model of energy and agriculture systems to show that, given a climate policy in which terrestrial carbon is appropriately valued equally with carbon emitted from the energy system, biomass energy has the potential to be a major component of achieving these low concentration targets. The costs of processing and transporting biomass energy at much larger scales than current experience are also incorporated into the modeling. From the scenario results, 120-160 EJ/year of biomass energy is produced by midcentury and 200-250 EJ/year by the end of this century. In the first half of the century, much of this biomass is from agricultural and forest residues, but after 2050 dedicated cellulosic biomass crops become the dominant source. A key finding of this paper is the role that carbon dioxide capture and storage (CCS) technologies coupled with commercial biomass energy can play in meeting stringent emissions targets. Despite the higher technology costs of CCS, the resulting negative emissions used in combination with biomass are a very important tool in controlling the cost of meeting a target, offsetting the venting of CO2 from sectors of the energy system that may be more expensive to mitigate, such as oil use in transportation. The paper also discusses the role of cellulosic ethanol and Fischer-Tropsch biomass derived transportation fuels and shows that both technologies are important contributors to liquid fuels production, with unique costs and emissions characteristics. Through application of the GCAM integrated assessment model, it becomes clear that, given CCS availability, bioenergy will be used both in electricity and transportation.

  6. Large Conductance Switching in a Single-Molecule Device through Room Temperature Spin-Dependent Transport.

    PubMed

    Aragonès, Albert C; Aravena, Daniel; Cerdá, Jorge I; Acís-Castillo, Zulema; Li, Haipeng; Real, José Antonio; Sanz, Fausto; Hihath, Josh; Ruiz, Eliseo; Díez-Pérez, Ismael

    2016-01-13

    Controlling the spin of electrons in nanoscale electronic devices is one of the most promising topics aiming at developing devices with rapid and high density information storage capabilities. The interface magnetism or spinterface resulting from the interaction between a magnetic molecule and a metal surface, or vice versa, has become a key ingredient in creating nanoscale molecular devices with novel functionalities. Here, we present a single-molecule wire that displays large (>10000%) conductance switching by controlling the spin-dependent transport under ambient conditions (room temperature in a liquid cell). The molecular wire is built by trapping individual spin crossover Fe(II) complexes between one Au electrode and one ferromagnetic Ni electrode in an organic liquid medium. Large changes in the single-molecule conductance (>100-fold) are measured when the electrons flow from the Au electrode to either an α-up or a β-down spin-polarized Ni electrode. Our calculations show that the current flowing through such an interface appears to be strongly spin-polarized, thus resulting in the observed switching of the single-molecule wire conductance. The observation of such a high spin-dependent conductance switching in a single-molecule wire opens up a new door for the design and control of spin-polarized transport in nanoscale molecular devices at room temperature.

  7. Probing Energy Levels of Large Array Quantum Dot Superlattice by Electronic Transport Measurement

    NASA Astrophysics Data System (ADS)

    Bisri, S. Z.; Degoli, E.; Spallanzani, N.; Krishnan, G.; Kooi, B.; Ghica, C.; Yarema, M.; Protesescu, L.; Heiss, W.; Kovalenko, M.; Pulci, O.; Ossicini, S.; Iwasa, Y.; Loi, M. A.

    2015-03-01

    Colloidal quantum dot superlattice (CQDS) emerges as new type of hybrid solids allowing easy fabrication of devices that exploits the quantum confinement properties of individual QD. This materials displays peculiar characters, making investigation of their transport properties nontrivial. Besides the bandgap variations, 0D nature of QD lead to the formation of discrete energy subbands. These subbands are crucial for multiple exciton generation (for efficient solar cell), thermoelectric material and multistate transistor. Full understanding of the CQDS energy level structure is vital to use them in complex devices. Here we show a powerful method to determine the CQDS electronic energy levels from their intrinsic charge transport characteristics. Via the use of ambipolar transistors with CQDS as active materials and gated using highly capacitive ionic liquid gating, Fermi energy can be largely tuned. It can access energy levels beyond QD's HOMO & LUMO. Ability to probe not only the bandgap, but also the discrete energy level from large assembly of QD at room temperature suggests the formation of energy minibands in this system.

  8. Large-scale Sedimentary Structures and Contaminant Transport: an Example from Cape Cod, Massachusetts

    NASA Astrophysics Data System (ADS)

    Mulligan, A.; Uchupi, E.

    2002-05-01

    A review of 289 borehole logs collected across Cape Cod reveals that two large glacial lakes once covered the peninsula. The older lake, which existed about 19,000 years ago, covered the east-west portion of Cape Cod and deposited clay, silt, and very fine sand across the area. The southern dam of this lake ultimately failed and large drainage channels were carved into the surface of the glaciolacustrine sediments. These eroded lake deposits were subsequently buried by the outwash plains of sand and gravel that make up the surficial geology of today. One of the major drainage channels in the lake deposit surface is located below the Massachusetts Military Reservation (MMR), a 34 square mile facility with >10 known groundwater contaminant plumes. We will present preliminary evidence that the buried paleochannel is exerting a strong control on the transport of several plumes at MMR and thus are critical stratigraphic structures that must be understood and delineated. Although fine-grained sediments are described in borehole logs from the MMR, infering the origin and significance of these deposits is made difficult by local-scale heterogeneities. The existence of the proglacial lake and the extensive, deep drainage channels are only apparent from investigating borehole data across a larger scale. This work illustrates the importance of characterizing the stratigraphic framework beyond the confines of a specific contamination site and further shows the controls that paleochannels filled with high permeability sediments can exert on flow and transport.

  9. Impact of compressibility on heat transport characteristics of large terrestrial planets

    NASA Astrophysics Data System (ADS)

    Čížková, Hana; van den Berg, Arie; Jacobs, Michel

    2017-07-01

    We present heat transport characteristics for mantle convection in large terrestrial exoplanets (M ⩽ 8M⊕) . Our thermal convection model is based on a truncated anelastic liquid approximation (TALA) for compressible fluids and takes into account a selfconsistent thermodynamic description of material properties derived from mineral physics based on a multi-Einstein vibrational approach. We compare heat transport characteristics in compressible models with those obtained with incompressible models based on the classical- and extended Boussinesq approximation (BA and EBA respectively). Our scaling analysis shows that heat flux scales with effective dissipation number as Nu ∼Dieff-0.71 and with Rayleigh number as Nu ∼Raeff0.27. The surface heat flux of the BA models strongly overestimates the values from the corresponding compressible models, whereas the EBA models systematically underestimate the heat flux by ∼10%-15% with respect to a corresponding compressible case. Compressible models are also systematically warmer than the EBA models. Compressibility effects are therefore important for mantle dynamic processes, especially for large rocky exoplanets and consequently also for formation of planetary atmospheres, through outgassing, and the existence of a magnetic field, through thermal coupling of mantle and core dynamic systems.

  10. Large-eddy transport in the surface layer over heterogeneous terrain

    NASA Astrophysics Data System (ADS)

    Mauder, M.; Eder, F.; De Roo, F.; Brugger, P.; Schmid, H. P. E.; Rotenberg, E.; Yakir, D.

    2015-12-01

    Surface heterogeneity and complex terrain invalidate to a certain extent basic assumptions behind the classical turbulence theory. One important classical concept is Townsend's hypothesis, which postulates that outer layer scale and inner layer scale turbulence do not interact. However, there is little knowledge to what extent large-scale eddies can affect near-surface fluxes. We shall investigate the relevance of large-eddy transport in the surface layer by an integrated approach combining field measurements and numerical simulations. Doppler lidar and tower-based turbulence measurements were conducted at the Yatir forest in Israel, which is surrounded by semi-arid shrubland. Vertical profiles of vertical and horizontal wind speed and direction were determined from Doppler lidar data. Eddy-covariance measurements were conducted at two sites. In addition, idealized large-eddy simulations (LES) were performed. A virtual control volume method allowed us to disentangle all components of the total surface flux. The daytime sensible heat flux over the forest was almost twice as large as over the surrounding shrubland. These very large differences in surface heating generated a secondary circulation, which was detected by the Doppler lidar measurements. Persistent updrafts were detected above the forest. Tower measurements at the shrubland site showed generally larger low-frequency contributions in spectra and co-spectra, and the energy balance ratio over the forest was 1.00, while it was only 0.81 at the shrubland site. LES results indicate that advection is the main cause for the lack of energy balance closure at the shrubland site. Over the forest, an equally large advective flux (in the opposite direction as over the shrubland) is almost completely balanced by horizontal flux divergence. We conclude that secondary circulations indeed exist over the Yatir forest, and that they can be detected from Doppler lidar data. Against the prediction of Townsend's hypothesis

  11. Upscaling of Large-Scale Transport in Spatially Heterogeneous Porous Media Using Wavelet Transformation

    NASA Astrophysics Data System (ADS)

    Moslehi, M.; de Barros, F.; Ebrahimi, F.; Sahimi, M.

    2015-12-01

    Modeling flow and solute transport in large-scale heterogeneous porous media involves substantial computational burdens. A common approach to alleviate this complexity is to utilize upscaling methods. These processes generate upscaled models with less complexity while attempting to preserve the hydrogeological properties comparable to the original fine-scale model. We use Wavelet Transformations (WT) of the spatial distribution of aquifer's property to upscale the hydrogeological models and consequently transport processes. In particular, we apply the technique to a porous formation with broadly distributed and correlated transmissivity to verify the performance of the WT. First, transmissivity fields are coarsened using WT in such a way that the high transmissivity zones, in which more important information is embedded, mostly remain the same, while the low transmissivity zones are averaged out since they contain less information about the hydrogeological formation. Next, flow and non-reactive transport are simulated in both fine-scale and upscaled models to predict both the concentration breakthrough curves at a control location and the large-scale spreading of the plume around its centroid. The results reveal that the WT of the fields generates non-uniform grids with an average of 2.1% of the number of grid blocks in the original fine-scale models, which eventually leads to a significant reduction in the computational costs. We show that the upscaled model obtained through the WT reconstructs the concentration breakthrough curves and the spreading of the plume at different times accurately. Furthermore, the impacts of the Hurst coefficient, size of the flow domain and the orders of magnitude difference in transmissivity values on the results have been investigated. It is observed that as the heterogeneity and the size of the domain increase, better agreement between the results of fine-scale and upscaled models can be achieved. Having this framework at hand aids

  12. Simulation and parameterization of the turbulent transport in the hurricane boundary layer by large eddies

    NASA Astrophysics Data System (ADS)

    Zhu, Ping

    2008-09-01

    Hurricane boundary layer (HBL) processes, especially the structure of the coherent large eddy circulations (LECs) and their induced vertical transport, are not well understood. This paper introduces a large eddy simulation (LES) framework in a weather hindcasting mode developed from a multiple scale nested Weather Research and Forecasting (WRF) model. Using the WRF-LES, this study investigated the structure of the HBL LECs and the associated vertical transport during the landfall of Hurricane Ivan (2004). The simulation shows that the HBL LECs exist in a mean stable environment and consist of well-defined updraft and downdraft. Statistically, the HBL LECs are only slightly skewed with the updrafts and downdrafts relatively evenly distributed spatially. The inversion base basically envelopes the upper boundary of LECs. The trough in between two adjacent LECs is where most entrainment takes place, whereas the crest of the LECs is where boundary layer air detrains out of the HBL. In such a way, LECs directly connect the surface, the HBL, and the main body of a hurricane vortex and enhance the exchange of energy, moisture, and momentum between them. It is found that the current boundary layer schemes significantly underestimate the resolved turbulent fluxes due to the fact that the effects of LECs have not been included in the parameterizations. On the basis of the statistical structure of LECs simulated by the WRF-LES, this paper proposes a conceptual updraft-downdraft model that can potentially be implemented in weather forecasting models to parameterize the fluxes induced by the HBL LEC transport.

  13. Fluid dynamics, sediment transport and turbulent mixing at large confluences of the Amazon River

    NASA Astrophysics Data System (ADS)

    Trevethan, Mark; Gualtieri, Carlo; Filizola, Naziano; Ianniruberto, Marco

    2014-05-01

    The Clim-Amazon Project aims to study temporal sedimentary records to understand the mechanisms involved in climate and geodynamic changes and the processes involved in dissolved and suspended load evolution of the Amazon River basin from the Miocene to present. The knowledge of the present Amazon River sediment discharge and of its variability is fundamental since it can be linked to the on-going climatic and erosion processes at the regional scale. Understanding the relationships between these processes will be helpful to better interpret the observations of the past sedimentation rates. Within this general objective the aim of this study is to investigate the complex fluid dynamics, sediment transport and water quality processes occurring at the large confluences in the Amazon River, through a combination of theoretical, experimental (field) and numerical research. In the last decades a wide body of theoretical, experimental, and field research has emerged on the fluvial dynamics of river confluences, which are integral and ubiquitous features of river networks. Through this research substantial advances have been made into understanding the hydrodynamics and morphodynamics of river confluences which will be outlined here. However, to date most experimental studies have focused either on laboratory confluences or on small to medium sized natural confluences, whereas an extremely limited number of investigations about the confluences on large rivers. Presently little is understood about how river confluence hydrodynamics may vary with the size of the river, especially in the largest rivers. The Amazon River is the largest river in the World, with approximately 15,000 sub-branches joining the Amazon River within the Amazon Basin including some of the largest confluences on Earth. A study region containing three of the larger confluences between Manacapuru and Itacoatiara will be used as part of this study, with the primary focus being the confluence of the Rio

  14. Observations of subsonic and supersonic shear flows in laser driven high-energy-density plasmas

    NASA Astrophysics Data System (ADS)

    Harding, E. C.

    2009-11-01

    Shear layers containing strong velocity gradients appear in many high-energy-density (HED) systems and play important roles in mixing and the transition to turbulence. Yet few laboratory experiments have been carried out to study their detailed evolution in this extreme environment where plasmas are compressible, actively ionizing, often involve strong shock waves and have complex material properties. Many shear flows produce the Kelvin-Helmholtz (KH) instability, which initiates the mixing at a fluid interface. We present results from two dedicated shear flow experiments that produced overall subsonic and supersonic flows using novel target designs. In the subsonic case, the Omega laser was used to drive a blast wave along a rippled interface between plastic and foam, shocking both the materials to produce two fluids separated by a sharp shear layer. The interface subsequently rolled-upped into large KH vortices that were accompanied by bubble-like structures of unknown origin. This was the first time the evolution of a well-resolved KH instability was observed in a HED plasma in the laboratory. We have analyzed the properties and dynamics of the plasma based on the data and fundamental models, without resorting to simulated values. In the second, supersonic experiment the Nike laser was used to drive a supersonic flow of Al plasma along a rippled, low-density foam surface. Here again the flowing plasma drove a shock into the second material, so that two fluids were separated by a shear layer. In contrast to the subsonic case, the flow developed shocks around the ripples in response to the supersonic flow of Al. Collaborators: R.P. Drake, O.A. Hurricane, J.F. Hansen, Y. Aglitskiy, T. Plewa, B.A. Remington, H.F. Robey, J.L. Weaver, A.L. Velikovich, R.S. Gillespie, M.J. Bono, M.J. Grosskopf, C.C. Kuranz, A. Visco.

  15. The influence of a very large wind farm on turbulent transport in the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Abkar, M.; Porté-Agel, F.

    2012-04-01

    Predicting wind and turbulent transport of heat, water vapor and pollutants through wind farms is of great importance for wind engineering, wind energy and environmental applications. It requires detailed knowledge of atmospheric boundary-layer (ABL) over a wide range of spatial and temporal scales. The complexity of such flows makes it difficult to obtain all the needed information through field experiments alone, and often necessitates high-resolution eddy-resolving numerical tools such as large-eddy simulation (LES). In this study, Large-eddy simulation is used to simulate atmospheric boundary-layer flow through a very large wind farm. To do this, tuning-free Lagrangian scale-dependent dynamic models (Stoll and Porte-Agel 2006) are used to model the subgrid-scale fluxes and the turbine-induced forces are parameterized using the actuator disk model (Wu and Porte-Agel 2011). The effect of large arrays of wind turbines on local/regional fluxes of momentum and scalar quantities under different stability conditions is assessed. Also, it will be shown how wind farms can change the vertical distribution of momentum and scalar fluxes inside the ABL. Particular attention is placed on the growth of the boundary layer height due to the presence of the wind turbines.

  16. Adaptive wall technology for three-dimensional models at high subsonic speeds and aerofoil testing through the speed of sound

    NASA Technical Reports Server (NTRS)

    Lewis, M. C.; Taylor, N. J.; Goodyer, M. J.

    1992-01-01

    Adaptive wall research at the University of Southampton has been directed towards the development of testing techniques for use in nonporous test sections where two flexible walls are profiled in single curvature. This paper highlights the recent advances that have been made in the testing of 2D airfoils through the speed of sound and the testing of 3D models at high subsonic speeds. Techniques have been developed to accommodate the variety of flow regimes encountered in near sonic airfoil tests. The experimental evidence to date suggests that the new techniques coupled with established procedures allow airfoil data, free from top and bottom wall interference, to be gathered from adaptive flexible walled test sections throughout the entire subsonic, transonic and supersonic speed ranges. Techniques applicable to the testing of 3D models have evolved primarily from experience gained by testing sidewall mounted half-wings. Emphasis has been placed upon models with planforms similar to those of current transport wings. Techniques for high subsonic speeds have now been developed to the point where the residual levels of interference are low.

  17. Adaptive wall technology for three-dimensional models at high subsonic speeds and aerofoil testing through the speed of sound

    NASA Technical Reports Server (NTRS)

    Lewis, M. C.; Taylor, N. J.; Goodyer, M. J.

    1992-01-01

    Adaptive wall research at the University of Southampton has been directed towards the development of testing techniques for use in nonporous test sections where two flexible walls are profiled in single curvature. This paper highlights the recent advances that have been made in the testing of 2D airfoils through the speed of sound and the testing of 3D models at high subsonic speeds. Techniques have been developed to accommodate the variety of flow regimes encountered in near sonic airfoil tests. The experimental evidence to date suggests that the new techniques coupled with established procedures allow airfoil data, free from top and bottom wall interference, to be gathered from adaptive flexible walled test sections throughout the entire subsonic, transonic and supersonic speed ranges. Techniques applicable to the testing of 3D models have evolved primarily from experience gained by testing sidewall mounted half-wings. Emphasis has been placed upon models with planforms similar to those of current transport wings. Techniques for high subsonic speeds have now been developed to the point where the residual levels of interference are low.

  18. Large wood transport dynamics on the low-gradient Roanoke River, North Carolina

    NASA Astrophysics Data System (ADS)

    Schenk, E. R.; Hupp, C. R.

    2011-12-01

    Large wood (LW) provides essential aquatic habitat in fine-grained low-gradient rivers. Unfortunately, there are relatively few studies on the sources and transport dynamics of large wood in Eastern U.S. rivers. The purposes of our study are to determine LW abundance and transport processes for the 210 kilometer (km) Coastal Plain segment of the dam-regulated Roanoke River, North Carolina. Our methods included collecting background geomorphic data including a 200 km channel geometry survey and measurements from 701 bank erosion pins at 36 cross-sections over 132 km. LW concentrations were evaluated over a 177 km reach using georeferenced aerial video taken in March 2007. LW transport was measured using 290 radio tagged LW pieces (mean diameter = 35.0 cm, length = 9.3 m) installed between 2008 and 2010. An additional 54 floating pieces were tagged with aluminum tree tags for a one week flood study in November 2009 (mean diameter = 29.2 cm, length = 5.2 m). The longitudinal distribution of aerially surveyed individual pieces of LW was highly variable with a mean abundance of 55 pieces/km. The abundance of LW in logjams was 59 pieces/km, with logjams concentrated (21.5 logjams/km) in an actively eroding reach with relatively high sinuosity, high local LW production rates, and narrow channel widths. Most jams (70%) are available nearly year round as aquatic habitat, positioned either on the lower bank or submerged at low-water flows. Conversely, individual LW pieces are found on the upper bank, with only 18% of the population located in the channel during low-water flows. Repeat surveys of radio tagged LW determined that transport is common despite dam regulation and a low channel gradient (0.0016). The mean distance travelled by a radio tagged piece of LW was 11.9 km with a maximum of 101 km (84 tags moved, 96 stationary, 110 not found). The mean distance travelled by an aluminum tagged LW was 13.3 km with a maximum of 72.12 km during the one week flood study (52 LW

  19. Switch-Loop Flexibility Affects Transport of Large Drugs by the Promiscuous AcrB Multidrug Efflux Transporter

    PubMed Central

    Cha, Hi-jea; Müller, Reinke T.

    2014-01-01

    Multidrug efflux transporters recognize a variety of structurally unrelated compounds for which the molecular basis is poorly understood. For the resistance nodulation and cell division (RND) inner membrane component AcrB of the AcrAB-TolC multidrug efflux system from Escherichia coli, drug binding occurs at the access and deep binding pockets. These two binding areas are separated by an 11-amino-acid-residue-containing switch loop whose conformational flexibility is speculated to be essential for drug binding and transport. A G616N substitution in the switch loop has a distinct and local effect on the orientation of the loop and on the ability to transport larger drugs. Here, we report a distinct phenotypical pattern of drug recognition and transport for the G616N variant, indicating that drug substrates with minimal projection areas of >70 Å2 are less well transported than other substrates. PMID:24914123

  20. Persistence of large-scale, 3-dimensional morphologic features in regions with large, alongshore sediment transport: observations of ebb tidal deltas using X-band radar (RIOS)

    NASA Astrophysics Data System (ADS)

    McNinch, J.; Humberston, J. L.

    2016-12-01

    The persistence of large-scale, nearshore morphologic features, such as shore-oblique bars and ebb tidal deltas, are difficult to reconcile on beaches with large, wave-driven alongshore transport volumes without assuming that: 1) hydrodynamic processes maintaining these features are sustained through a variety of oceanographic conditions, and 2) large volumes of sediment bypasses the features during periods of strong alongshore transport. One would otherwise expect wave events to diffuse shore-oblique features into more 2-D, linear forms typically observed on shore-parallel sand bars in the inner surf zone. Understanding the modes of sediment transport occurring (e.g. small, migrating sand waves as observed in riverine settings; bedload transport along existing large-scale morphological features; and/or event-driven suspended sediment transport) is important to accurately model alongshore, 3-D beach morphology and tidal inlet morphodynamics. Part of the challenge is the paucity of observational data and the difficulty in measuring bathymetry over these features at high temporal and spatial resolutions in all conditions. We explore the morphologic evolution of shoals comprising two ebb tidal deltas in regions with significant wave-driven, alongshore sediment transport using data collected by Radar Inlet Observing System (RIOS). RIOS utilizes hourly X-band radar data (1Hz, 10-min duration) to define shoal positions and morphology from measured wave breaking and wave speed. Extended time series (>3 months) of RIOS-defined shoals at Oregon Inlet, NC and St. Augustine Inlet, FL are used to test the hypothesis that the large-scale shoals comprising the ebb tidal deltas remain relatively static while still allowing a substantial volume of alongshore sediment throughput. Early results support this hypothesis, suggesting bed load transport and shore-parallel bedform migration may dominate inlet bypassing in these systems instead of the more traditionally accepted bulk

  1. Heat transport in the high-pressure ice mantle of large icy moons

    NASA Astrophysics Data System (ADS)

    Choblet, G.; Tobie, G.; Sotin, C.; Kalousová, K.; Grasset, O.

    2017-03-01

    While the existence of a buried ocean sandwiched between surface ice and high-pressure (HP) polymorphs of ice emerges as the most plausible structure for the hundreds-of-kilometers thick hydrospheres within large icy moons of the Solar System (Ganymede, Callisto, Titan), little is known about the thermal structure of the deep HP ice mantle and its dynamics, possibly involving melt production and extraction. This has major implications for the thermal history of these objects as well as on the habitability of their ocean as the HP ice mantle is presumed to limit chemical transport from the rock component to the ocean. Here, we describe 3D spherical simulations of subsolidus thermal convection tailored to the specific structure of the HP ice mantle of large icy moons. Melt production is monitored and melt transport is simplified by assuming instantaneous extraction to the ocean above. The two controlling parameters for these models are the rheology of ice VI and the heat flux from the rock core. Reasonable end-members are considered for both parameters as disagreement remains on the former (especially the pressure effect on viscosity) and as the latter is expected to vary significantly during the moon's history. We show that the heat power produced by radioactive decay within the rock core is mainly transported through the HP ice mantle by melt extraction to the ocean, with most of the melt produced directly above the rock/water interface. While the average temperature in the bulk of the HP ice mantle is always relatively cool when compared to the value at the interface with the rock core (∼ 5 K above the value at the surface of the HP ice mantle), maximum temperatures at all depths are close to the melting point, often leading to the interconnection of a melt path via hot convective plume conduits throughout the HP ice mantle. Overall, we predict long periods of time during these moons' history where water generated in contact with the rock core is transported to

  2. Heat transport in the high-pressure ice mantle of large icy moons

    NASA Astrophysics Data System (ADS)

    Choblet, Gael; Tobie, Gabriel; Sotin, Christophe; Kalousova, Klara; Grasset, Olivier

    2017-04-01

    While the existence of a buried ocean sandwiched between surface ice and high-pressure (HP) polymorphs of ice emerges as the most plausible structure for the hundreds-of-kilometers thick hydrospheres within large icy moons of the Solar System (Ganymede, Callisto, Titan), little is known about the thermal structure of the deep HP ice mantle and its dynamics, possibly involving melt production and extraction. This has major implications for the thermal history of these objects as well as on the habitability of their ocean as the HP ice mantle is presumed to limit chemical transport from the rock component to the ocean. Here, we describe 3D spherical simulations of subsolidus thermal convection tailored to the specific structure of the HP ice mantle of large icy moons. Melt production is monitored and melt transport is simplified by assuming instantaneous extraction to the ocean above. The two controlling parameters for these models are the rheology of ice VI and the heat flux from the rock core. Reasonable end-members are considered for both parameters as disagreement remains on the former (especially the pressure effect on viscosity) and as the latter is expected to vary significantly during the moon's history. We show that the heat power produced by radioactive decay within the rock core is mainly transported through the HP ice mantle by melt extraction to the ocean, with most of the melt produced directly above the rock/water interface. While the average temperature in the bulk of the HP ice mantle is always relatively cool when compared to the value at the interface with the rock core (˜ 5 K above the value at the surface of the HP ice mantle), maximum temperatures at all depths are close to the melting point, often leading to the interconnection of a melt path via hot convective plume conduits throughout the HP ice mantle. Overall, we predict long periods of time during these moons' history where water generated in contact with the rock core is transported to

  3. CFD-Based Design Optimization Tool Developed for Subsonic Inlet

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The traditional approach to the design of engine inlets for commercial transport aircraft is a tedious process that ends with a less-than-optimum design. With the advent of high-speed computers and the availability of more accurate and reliable computational fluid dynamics (CFD) solvers, numerical optimization processes can effectively be used to design an aerodynamic inlet lip that enhances engine performance. The designers' experience at Boeing Corporation showed that for a peak Mach number on the inlet surface beyond some upper limit, the performance of the engine degrades excessively. Thus, our objective was to optimize efficiency (minimize the peak Mach number) at maximum cruise without compromising performance at other operating conditions. Using a CFD code NPARC, the NASA Lewis Research Center, in collaboration with Boeing, developed an integrated procedure at Lewis to find the optimum shape of a subsonic inlet lip and a numerical optimization code, ADS. We used a GRAPE-based three-dimensional grid generator to help automate the optimization procedure. The inlet lip shape at the crown and the keel was described as a superellipse, and the superellipse exponents and radii ratios were considered as design variables. Three operating conditions: cruise, takeoff, and rolling takeoff, were considered in this study. Three-dimensional Euler computations were carried out to obtain the flow field. At the initial design, the peak Mach numbers for maximum cruise, takeoff, and rolling takeoff conditions were 0.88, 1.772, and 1.61, respectively. The acceptable upper limits on the takeoff and rolling takeoff Mach numbers were 1.55 and 1.45. Since the initial design provided by Boeing was found to be optimum with respect to the maximum cruise condition, the sum of the peak Mach numbers at takeoff and rolling takeoff were minimized in the current study while the maximum cruise Mach number was constrained to be close to that at the existing design. With this objective, the

  4. Large-scale suspended sediment transport and sediment deposition in the Mekong Delta

    NASA Astrophysics Data System (ADS)

    Manh, N. V.; Dung, N. V.; Hung, N. N.; Merz, B.; Apel, H.

    2014-08-01

    Sediment dynamics play a major role in the agricultural and fishery productivity of the Mekong Delta. However, the understanding of sediment dynamics in the delta, one of the most complex river deltas in the world, is very limited. This is a consequence of its large extent, the intricate system of rivers, channels and floodplains, and the scarcity of observations. This study quantifies, for the first time, the suspended sediment transport and sediment deposition in the whole Mekong Delta. To this end, a quasi-2D hydrodynamic model is combined with a cohesive sediment transport model. The combined model is calibrated using six objective functions to represent the different aspects of the hydraulic and sediment transport components. The model is calibrated for the extreme flood season in 2011 and shows good performance for 2 validation years with very different flood characteristics. It is shown how sediment transport and sediment deposition is differentiated from Kratie at the entrance of the delta on its way to the coast. The main factors influencing the spatial sediment dynamics are the river and channel system, dike rings, sluice gate operations, the magnitude of the floods, and tidal influences. The superposition of these factors leads to high spatial variability of sediment transport, in particular in the Vietnamese floodplains. Depending on the flood magnitude, annual sediment loads reaching the coast vary from 48 to 60% of the sediment load at Kratie. Deposited sediment varies from 19 to 23% of the annual load at Kratie in Cambodian floodplains, and from 1 to 6% in the compartmented and diked floodplains in Vietnam. Annual deposited nutrients (N, P, K), which are associated with the sediment deposition, provide on average more than 50% of mineral fertilizers typically applied for rice crops in non-flooded ring dike floodplains in Vietnam. Through the quantification of sediment and related nutrient input, the presented study provides a quantitative basis for

  5. Measurement of Large-Scale Sediment Transport Dynamics Using Multibeam Sonar

    NASA Astrophysics Data System (ADS)

    Simmons, S. M.; Parsons, D. R.; Best, J. L.; Malzone, C.; Keevil, G.

    2007-12-01

    Multibeam Echo-Sounder (MBES) sonar systems have developed rapidly over recent decades and are now routinely deployed to provide high-resolution object detection and bathymetric surveying in a range of aquatic environments, from the deep-sea to lakes and rivers. MBES systems were developed for bottom-detection and measurement of bed morphology, and have previously discarded the received acoustic back-scatter from the water column after the bottom-detection algorithms have been performed. However, modern data handling and storage technologies have facilitated the logging of this large quantity of acoustic intensity and phase information, and commercial MBES systems are now available that provide this capability. This paper develops a novel methodology to exploit this logging capability to quantify the concentration and dynamics of suspended sediment within the water column. This development provides a multi-purpose tool for the holistic surveying of sediment transport by imaging suspended sediment concentration, associated coherent flow structures and providing concurrent high-resolution bathymetry. This paper presents methods of data analysis and results obtained from deployment of the RESON SeaBat 8125 and 7125 MBES systems in the field and during testing in a controlled environment. The field results were obtained from sites on the Paraná river, Argentina, with the aim of examining the dynamics of suspended sediment transport over dune bedforms and in the region of flow mixing between large rivers of significantly different suspended sediment concentration. Controlled testing was performed in a former ship dry-dock by creating flows density currents of known suspended sediment concentration with different types and mixes of sediment. The results demonstrate the capability of the RESON MBES systems to successfully resolve the contrast in suspended sediment concentration, and hence the spatio-temporal monitoring of the associated coherent flow structures. The

  6. Numerical Experiments on Advective Transport in Large Three-Dimensional Discrete Fracture Networks

    NASA Astrophysics Data System (ADS)

    Makedonska, N.; Painter, S. L.; Karra, S.; Gable, C. W.

    2013-12-01

    Modeling of flow and solute transport in discrete fracture networks is an important approach for understanding the migration of contaminants in impermeable hard rocks such as granite, where fractures provide dominant flow and transport pathways. The discrete fracture network (DFN) model attempts to mimic discrete pathways for fluid flow through a fractured low-permeable rock mass, and may be combined with particle tracking simulations to address solute transport. However, experience has shown that it is challenging to obtain accurate transport results in three-dimensional DFNs because of the high computational burden and difficulty in constructing a high-quality unstructured computational mesh on simulated fractures. An integrated DFN meshing [1], flow, and particle tracking [2] simulation capability that enables accurate flow and particle tracking simulation on large DFNs has recently been developed. The new capability has been used in numerical experiments on advective transport in large DFNs with tens of thousands of fractures and millions of computational cells. The modeling procedure starts from the fracture network generation using a stochastic model derived from site data. A high-quality computational mesh is then generated [1]. Flow is then solved using the highly parallel PFLOTRAN [3] code. PFLOTRAN uses the finite volume approach, which is locally mass conserving and thus eliminates mass balance problems during particle tracking. The flow solver provides the scalar fluxes on each control volume face. From the obtained fluxes the Darcy velocity is reconstructed for each node in the network [4]. Velocities can then be continuously interpolated to any point in the domain of interest, thus enabling random walk particle tracking. In order to describe the flow field on fractures intersections, the control volume cells on intersections are split into four planar polygons, where each polygon corresponds to a piece of a fracture near the intersection line. Thus

  7. Research on new-style flexure supports method for large-aperture transport mirror mounting

    NASA Astrophysics Data System (ADS)

    Quan, Xusong; Zhang, Zheng; Xiong, Zhao; Wang, Hui; Yuan, Xiaodong; Liu, Changchun

    2016-10-01

    In high-power solid-state laser facility (SG-III), focusing laser beams into the target center with precision better than 50 microns (RMS) is dependent on the stringent specifications of thousands of large-aperture transport mirror units and is a huge challenge on the surface aberration control of mirrors. The current mirror's mounting techniques with screw fastening loads has several engineering conundrums - low control precision for loads (higher scatter even +/-30%), and low assembly-rectification efficiency ( 100 screws). To improve the current screw-fastening method, a new-style flexure supports method, which has a wonderful performance on uniform control of the external loads and only uses 30 screws, is proposed to mount the mirror (size: 610mm×440mm×85mm). With theoretical modeling and FEM analysis, the impacts of mounting loads on mirror's surface aberrations are analyzed and discussed in detail, and the flexure supports system is designed. Finally, with experimental research and case studies, the proposed flexure supports method shows a powerful performance on even control precision of external loads with scatter even less than +/-10%, which is a promising mounting process to replace the threaded fasteners mounting the large-aperture optics. These improvements can lay a foundation for mounting process consistency, robustness, and assembly-rectification efficiency of large optical component.

  8. Trends in large wood storage and transport on the low-gradient Roanoke River, North Carolina

    NASA Astrophysics Data System (ADS)

    Schenk, E. R.; Hupp, C. R.

    2010-12-01

    Large wood (LW) provides essential aquatic habitat in fine-grained low-gradient rivers. Unfortunately, there is a paucity of large-river LW data for the Eastern USA, especially in the low relief clay and fine sand dominated Coastal Plain province. The purposes of our study are to determine LW abundance and transport processes for the 210 kilometer (km) Coastal Plain segment of the dam-regulated Roanoke River, North Carolina. Our methods included collecting background geomorphic data including a 200 km channel geometry survey and measurements from 701 bank erosion pins at 36 cross-sections over 132 km. LW concentrations were evaluated over a 177 km reach using georeferenced aerial video taken in March 2007. LW transport was measured using 290 radio tagged LW pieces (mean diameter = 35.0 cm, length = 9.3 m) installed between 2008 and 2010. An additional 54 floating pieces were tagged with aluminum tree tags for a one week flood study in November 2009 (mean diameter = 29.2 cm, length = 5.2 m). The longitudinal distribution of aerially surveyed individual pieces of LW was highly variable with a mean abundance of 55 pieces/km. The abundance of LW in logjams was 59 pieces/km, with logjams concentrated (21.5 logjams/km) in an actively eroding reach with relatively high sinuosity, high local LW production rates, and narrow channel widths. Most jams (70%) are available nearly year round as aquatic habitat, positioned either on the lower bank or submerged at low-water flows. Conversely, individual LW pieces are found on the upper bank, with only 18% of the population located in the channel during low-water flows. Repeat surveys of radio tagged LW determined that transport is common despite dam regulation and a low channel gradient (0.0016). The mean distance travelled by a radio tagged piece of LW was 19.0 km with a maximum of 84.6 km (49 tags moved, 53 stationary, 188 not found). The mean distance travelled by an aluminum tagged LW was 13.3 km with a maximum of 72.12 km

  9. A COMPREHENSIVE ANALYSIS OF CHLORINE TRANSPORT AND FATE FOLLOWING A LARGE ENVIRONMENTAL RELEASE

    SciTech Connect

    Buckley, R.; Hunter, C.; Werth, D.; Chen, K.; Whiteside, M.; Mazzola, C.

    2011-05-10

    A train derailment occurred in Graniteville, South Carolina during the early morning of January 6, 2005, and resulted in the release of a large amount of cryogenic pressurized liquid chlorine to the environment in a short time period. A comprehensive evaluation of the transport and fate of the released chlorine was performed, accounting for dilution, diffusion, transport and deposition into the local environment. This involved the characterization of a three-phased chlorine release, a detailed determination of local atmospheric mechanisms acting on the released chlorine, the establishment of atmospheric-hydrological physical exchange mechanisms, and aquatic dilution and mixing. This presentation will provide an overview of the models used in determining the total air-to-water mass transfer estimated to have occurred as a result of the roughly 60 tons of chlorine released into the atmosphere from the train derailment. The assumptions used in the modeling effort will be addressed, along with a comparison with available observational data to validate the model results. Overall, model-estimated chlorine concentrations in the airborne plume compare well with human and animal exposure data collected in the days after the derailment.

  10. Seasonal characteristics of the large-scale moisture flux transport over the Arabian Peninsula

    NASA Astrophysics Data System (ADS)

    Athar, H.; Ammar, K.

    2016-05-01

    The relationship between the lower tropospheric (1000 to 850 hPa) large-scale moisture flux transport and the precipitation over the Arabian Peninsula (AP), on a seasonal basis, using the NCEP-NCAR gridded dataset for the 53-year period (1958-2010), is investigated. The lower tropospheric moisture flux divergence occurs due to the Hadley cell-based descending air over the AP, as well as due to the presence of Somali jet in dry season (June to September) for the southern (≤22° N) AP domain, leading to significantly reduced precipitation in the AP. The AP thus acts more as a net transporter of moisture flux from adjacent Sea areas to nearby regions. The North Atlantic Oscillation (NAO) and the Artic Oscillation (AO) climatic indices are found to modulate significantly the net seasonal moisture flux into the AP region animating from the Mediterranean Sea, and the Arabian Sea, both for the northern (≥22° N) and southern AP domains.

  11. Ghost transmission: How large basis sets can make electron transport calculations worse

    SciTech Connect

    Herrmann, Carmen; Solomon, Gemma C.; Subotnik, Joseph E.; Mujica, Vladimiro; Ratner, Mark A.

    2010-01-01

    The Landauer approach has proven to be an invaluable tool for calculating the electron transport properties of single molecules, especially when combined with a nonequilibrium Green’s function approach and Kohn–Sham density functional theory. However, when using large nonorthogonal atom-centered basis sets, such as those common in quantum chemistry, one can find erroneous results if the Landauer approach is applied blindly. In fact, basis sets of triple-zeta quality or higher sometimes result in an artificially high transmission and possibly even qualitatively wrong conclusions regarding chemical trends. In these cases, transport persists when molecular atoms are replaced by basis functions alone (“ghost atoms”). The occurrence of such ghost transmission is correlated with low-energy virtual molecular orbitals of the central subsystem and may be interpreted as a biased and thus inaccurate description of vacuum transmission. An approximate practical correction scheme is to calculate the ghost transmission and subtract it from the full transmission. As a further consequence of this study, it is recommended that sensitive molecules be used for parameter studies, in particular those whose transmission functions show antiresonance features such as benzene-based systems connected to the electrodes in meta positions and other low-conducting systems such as alkanes and silanes.

  12. Case study; Roller compacted concrete road for large off-road combustion waste transport

    SciTech Connect

    Brown, L.E. )

    1991-01-01

    This paper reports on the Gibbons creek Steam Electric Station (GCSES)-which generates combustion wastes, consisting of ash and scrubber sludge, at a rate of approximately 1.5 million cubic yards per year. Recognizing that the existing landfill would be filled to capacity in the near future, the Texas Municipal Power Agency (TMPA) retained Black and Veatch (B and V) to develop a combustion waste disposal plan and to design a landfill for the remaining 35-year life of the station. Several potential sites were evaluated on the basis of functional requirements, regulatory requirements, physical considerations, public sensitivity, and economic criteria. The evaluation of potential sites resulted in the selection of a site approximately 1-1/2 miles north of the GCSES main plant complex, across the cooling lake for the station. Several methods of transport were evaluated, including truck, conveyor, and rail. Hauling by large off-road trucks was determined to be the most reliable and cost-effective method of combustion waste transport.

  13. Large-eddy simulation of oxygen transport and depletion in waterbodies

    NASA Astrophysics Data System (ADS)

    Scalo, Carlo; Piomelli, Ugo; Boegman, Leon

    2010-11-01

    Dissolved oxygen (DO) in water plays an important role in lake and marine ecosystems. Agricultural runoff may spur excessive plant growth on the water surface; when the plants die they sink to the bottom of the water bodies and decompose, consuming oxygen. Significant environmental (and economic) damage may result from the loss of aquatic life caused by the oxygen depletion. The study of DO transport and depletion dynamics in water bodies has, therefore, become increasingly important. We study this phenomenon by large-eddy simulations performed at laboratory scale. The equations governing the transport of momentum and of a scalar (the DO) in the fluid are coupled to a biochemical model for DO depletion in the permeable sediment bed [Higashino et al., Water Res. (38) 1, 2004)], and to an equation for the fluid transpiration in the porous medium. The simulations are in good agreement with previous calculations and experiments. We show that the results are sensitive to the biochemical and fluid dynamical properties of the sediment, which are very difficult to determine experimentally.

  14. Oil droplets transport due to irregular waves: Development of large-scale spreading coefficients.

    PubMed

    Geng, Xiaolong; Boufadel, Michel C; Ozgokmen, Tamay; King, Thomas; Lee, Kenneth; Lu, Youyu; Zhao, Lin

    2016-03-15

    The movement of oil droplets due to waves and buoyancy was investigated by assuming an irregular sea state following a JONSWAP spectrum and four buoyancy values. A technique known as Wheeler stretching was used to model the movement of particles under the moving water surface. In each simulation, 500 particles were released and were tracked for a real time of 4.0 h. A Monte Carlo approach was used to obtain ensemble properties. It was found that small eddy diffusivities that decrease rapidly with depth generated the largest horizontal spreading of the plume. It was also found that large eddy diffusivities that decrease slowly with depth generated the smallest horizontal spreading coefficient of the plume. The increase in buoyancy resulted in a decrease in the horizontal spreading coefficient, which suggests that two-dimensional (horizontal) models that predict the transport of surface oil could be overestimating the spreading of oil.

  15. Dynamics Modeling and Simulation of Large Transport Airplanes in Upset Conditions

    NASA Technical Reports Server (NTRS)

    Foster, John V.; Cunningham, Kevin; Fremaux, Charles M.; Shah, Gautam H.; Stewart, Eric C.; Rivers, Robert A.; Wilborn, James E.; Gato, William

    2005-01-01

    As part of NASA's Aviation Safety and Security Program, research has been in progress to develop aerodynamic modeling methods for simulations that accurately predict the flight dynamics characteristics of large transport airplanes in upset conditions. The motivation for this research stems from the recognition that simulation is a vital tool for addressing loss-of-control accidents, including applications to pilot training, accident reconstruction, and advanced control system analysis. The ultimate goal of this effort is to contribute to the reduction of the fatal accident rate due to loss-of-control. Research activities have involved accident analyses, wind tunnel testing, and piloted simulation. Results have shown that significant improvements in simulation fidelity for upset conditions, compared to current training simulations, can be achieved using state-of-the-art wind tunnel testing and aerodynamic modeling methods. This paper provides a summary of research completed to date and includes discussion on key technical results, lessons learned, and future research needs.

  16. Graphene oxide hole transport layers for large area, high efficiency organic solar cells

    SciTech Connect

    Smith, Chris T. G.; Rhodes, Rhys W.; Beliatis, Michail J.; Imalka Jayawardena, K. D. G.; Rozanski, Lynn J.; Mills, Christopher A.; Silva, S. Ravi P.

    2014-08-18

    Graphene oxide (GO) is becoming increasingly popular for organic electronic applications. We present large active area (0.64 cm{sup 2}), solution processable, poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1, 3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]:[6,6]-Phenyl C{sub 71} butyric acid methyl ester (PCDTBT:PC{sub 70}BM) organic photovoltaic (OPV) solar cells, incorporating GO hole transport layers (HTL). The power conversion efficiency (PCE) of ∼5% is the highest reported for OPV using this architecture. A comparative study of solution-processable devices has been undertaken to benchmark GO OPV performance with poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) HTL devices, confirming the viability of GO devices, with comparable PCEs, suitable as high chemical and thermal stability replacements for PEDOT:PSS in OPV.

  17. Structure-based ligand discovery for the Large-neutral Amino Acid Transporter 1, LAT-1

    PubMed Central

    Geier, Ethan G.; Schlessinger, Avner; Fan, Hao; Gable, Jonathan E.; Irwin, John J.; Sali, Andrej; Giacomini, Kathleen M.

    2013-01-01

    The Large-neutral Amino Acid Transporter 1 (LAT-1)—a sodium-independent exchanger of amino acids, thyroid hormones, and prescription drugs—is highly expressed in the blood–brain barrier and various types of cancer. LAT-1 plays an important role in cancer development as well as in mediating drug and nutrient delivery across the blood–brain barrier, making it a key drug target. Here, we identify four LAT-1 ligands, including one chemically novel substrate, by comparative modeling, virtual screening, and experimental validation. These results may rationalize the enhanced brain permeability of two drugs, including the anticancer agent acivicin. Finally, two of our hits inhibited proliferation of a cancer cell line by distinct mechanisms, providing useful chemical tools to characterize the role of LAT-1 in cancer metabolism. PMID:23509259

  18. Manufacturing and NDE of Large Composite Structures for Space Transportation at MSFC

    NASA Technical Reports Server (NTRS)

    McGill, Preston; Russell, Sam

    2000-01-01

    This paper presents the Marshall Space Flight Center's (MSFC's) vision to manufacture, increase safety and reduce the cost of launch vehicles. Nondestructive evaluations of large composite structures are tested for space transportation at MSFC. The topics include: 1) 6 1/2 Generations of Airplanes in a Century; 2) Shuttle Safety Upgrades; 3) Generations of Reusable Launch Vehicles; 4) RLV Technology Demonstration Path; 5) Second Generation; 6) Key NASA Requirements; 7) X-33 Elements; 8) Future-X Pathfinder Projects and Experiments; 9) Focus Area Technical Goals; 10) X-34 Expanded View; 11) X-38 Spacecraft with De-Orbit Propulsion Stage (DPS); 12) Deorbit Module (DM) Critical Design Review (CDR) Design; 13) Forward Structural Adapter (FSA) CDR Design; 14) X-38 DPS CDR Design; 15) RLV Focused Propulsion Technologies; and 16) Challenges in Technology. This paper is presented in viewgraph form.

  19. On the Complexity of Nutrient Transport in a Large Watershed in Ohio

    NASA Astrophysics Data System (ADS)

    Schwartz, F. W.; Allen, G.

    2009-12-01

    This paper examines key features of the hydrobiologic setting in controlling the cycling of nutrients through the major streams and rivers of a large agriculturally dominated watershed in central Ohio. The particular focus is on the roles of extreme rainfall events in generating nutrients, and role of reservoirs in attenuating nutrient concentrations. The study also highlights major gaps in process knowledge even in the face in the face of extensive regulatory and other monitoring. Although it has been recognized that reservoirs can significantly affect surface-water flows in watersheds, there is a growing recognition of the need for expanded and complementary studies to understand their role in nutrient transport. The study area is located in central Ohio and includes the entire Upper Scioto and the northern portion of the Lower Scioto River basins, an area encompassing approximately 9984 km2. Five of the sub-watersheds contain major surface-water storage reservoirs. Two watersheds are without reservoirs. There is intensive agriculture within the study area with corn and soybeans as the dominant crops. Tile drainage of fields provides an efficient and rapid connection of agricultural lands to surface waters, facilitating the loading of fertilizers and agrochemicals to surface streams. Storm flows in spring months that coincide with fertilizer applications often provide nitrate concentrations in excess of 10 mg/L as N. In spite of years of routine sampling for regulatory purposes, little is known about nutrient loading patterns during the few, brief, extreme events each year. Interpretations of a high resolution temporal chemical record of sampling on the Scioto River is frustrated by the complexity of loading and mixing as tributaries from sub-watersheds join the main stem of the Scioto River and nutrient utilization within the large reservoirs. Even with literally thousands of individual chemical measurements, extensive stream and precipitation data, the details

  20. Large-scale modeling of reactive solute transport in fracture zones of granitic bedrocks.

    PubMed

    Molinero, Jorge; Samper, Javier

    2006-01-10

    Final disposal of high-level radioactive waste in deep repositories located in fractured granite formations is being considered by several countries. The assessment of the safety of such repositories requires using numerical models of groundwater flow, solute transport and chemical processes. These models are being developed from data and knowledge gained from in situ experiments such as the Redox Zone Experiment carried out at the underground laboratory of Aspö in Sweden. This experiment aimed at evaluating the effects of the construction of the access tunnel on the hydrogeological and hydrochemical conditions of a fracture zone intersected by the tunnel. Most chemical species showed dilution trends except for bicarbonate and sulphate which unexpectedly increased with time. Molinero and Samper [Molinero, J. and Samper, J. Groundwater flow and solute transport in fracture zones: an improved model for a large-scale field experiment at Aspö (Sweden). J. Hydraul. Res., 42, Extra Issue, 157-172] presented a two-dimensional water flow and solute transport finite element model which reproduced measured drawdowns and dilution curves of conservative species. Here we extend their model by using a reactive transport which accounts for aqueous complexation, acid-base, redox processes, dissolution-precipitation of calcite, quartz, hematite and pyrite, and cation exchange between Na+ and Ca2+. The model provides field-scale estimates of cation exchange capacity of the fracture zone and redox potential of groundwater recharge. It serves also to identify the mineral phases controlling the solubility of iron. In addition, the model is useful to test the relevance of several geochemical processes. Model results rule out calcite dissolution as the process causing the increase in bicarbonate concentration and reject the following possible sources of sulphate: (1) pyrite dissolution, (2) leaching of alkaline sulphate-rich waters from a nearby rock landfill and (3) dissolution of

  1. Transport of creosote compounds in a large, intact, macroporous clayey till column

    NASA Astrophysics Data System (ADS)

    Broholm, Kim; Jørgensen, Peter R.; Hansen, Asger B.; Arvin, Erik; Hansen, Martin

    1999-10-01

    The transport in macroporous clayey till of bromide and 25 organic compounds typical of creosote was studied using a large intact soil column. The organic compounds represented the following groups: polycyclic aromatic hydrocarbons (PAHs), phenolic compounds, monoaromatic hydrocarbons (BTEXs), and heterocyclic compounds containing oxygen, nitrogen or sulphur in the aromatic ring structure (NSO-compounds). The clayey till column (0.5 m in height and 0.5 m in diameter) was obtained from a depth of 1-1.5 m at an experimental site located on the island of Funen, Denmark. Sodium azide was added to the influent water of the column to prevent biodegradation of the studied organic compounds. For the first 24 days of the experiment, the flow rate was 219 ml day -1 corresponding to an infiltration rate of 0.0011 m day -1. At this flow rate, the effluent concentrations of bromide and the organic compounds increased very slowly. The transport of bromide and the organic compounds were successfully increased by increasing the flow rate to 1353 ml day -1 corresponding to 0.0069 m day -1. The experiment showed that the transport of low-molecular-weight organic compounds was not retarded relative to bromide. The high-molecular-weight organic compounds were retarded significantly. The influence of sorption on the transport of the organic compounds through the column was evaluated based on the observed breakthrough curves. The observed order in the column experiment was, with increasing retardation, the following: benzene=pyrrole=toluene= o-xylene= p-xylene=ethylbenzene=phenol=benzothiophene=benzofuran

  2. Influence of large changes in public transportation (Transantiago) on the black carbon pollution near streets

    NASA Astrophysics Data System (ADS)

    Gramsch, E.; Le Nir, G.; Araya, M.; Rubio, M. A.; Moreno, F.; Oyola, P.

    2013-02-01

    In 2006 a large transformation was carried out on the public transportation system in Santiago de Chile. The original system (before 2006) had hundreds of bus owners with about 7000 diesel buses. The new system has only 13 firms with about 5900 buses which operate in different parts of the city with little overlap between them. In this work we evaluate the impact of the Transantiago system on the black carbon pollution along four roads directly affected by the modification to the transport system. Measurements were carried out during May-July of 2005 (before Transantiago) and June-July of 2007 (after Transantiago). We have used the Wilcoxon rank-sum test to evaluate black carbon concentration in four streets in year 2005 and 2007. The results show that a statistically significant reduction between year 2005 (before Transantiago) and year 2007 (after Transantiago) in Alameda street, which changed from a mean of 18.8 μg m-3 in 2005 to 11.9 μg m-3 in 2007. In this street there was a decrease in the number of buses as well as the number of private vehicles and an improvement in the technology of public transportation between those years. Other two streets (Usach and Departamental) did not change or experienced a small increase in the black carbon concentration in spite of having less flux of buses in 2007. Eliodoro Yañez Street, which did not have public transportation in 2005 or 2007 experienced a 15% increase in the black carbon concentration between those years. Analysis of the data indicates that the change is related to a decrease in the total number of vehicles or the number of other diesel vehicles in the street rather than a decrease in the number of buses only. These results are an indication that in order to decrease pollution near a street is not enough to reduce the number of buses or improve its quality, but to reduce the total number of vehicles.

  3. Large-scale modeling of reactive solute transport in fracture zones of granitic bedrocks

    NASA Astrophysics Data System (ADS)

    Molinero, Jorge; Samper, Javier

    2006-01-01

    Final disposal of high-level radioactive waste in deep repositories located in fractured granite formations is being considered by several countries. The assessment of the safety of such repositories requires using numerical models of groundwater flow, solute transport and chemical processes. These models are being developed from data and knowledge gained from in situ experiments such as the Redox Zone Experiment carried out at the underground laboratory of Äspö in Sweden. This experiment aimed at evaluating the effects of the construction of the access tunnel on the hydrogeological and hydrochemical conditions of a fracture zone intersected by the tunnel. Most chemical species showed dilution trends except for bicarbonate and sulphate which unexpectedly increased with time. Molinero and Samper [Molinero, J. and Samper, J. Groundwater flow and solute transport in fracture zones: an improved model for a large-scale field experiment at Äspö (Sweden). J. Hydraul. Res., 42, Extra Issue, 157-172] presented a two-dimensional water flow and solute transport finite element model which reproduced measured drawdowns and dilution curves of conservative species. Here we extend their model by using a reactive transport which accounts for aqueous complexation, acid-base, redox processes, dissolution-precipitation of calcite, quartz, hematite and pyrite, and cation exchange between Na + and Ca 2+. The model provides field-scale estimates of cation exchange capacity of the fracture zone and redox potential of groundwater recharge. It serves also to identify the mineral phases controlling the solubility of iron. In addition, the model is useful to test the relevance of several geochemical processes. Model results rule out calcite dissolution as the process causing the increase in bicarbonate concentration and reject the following possible sources of sulphate: (1) pyrite dissolution, (2) leaching of alkaline sulphate-rich waters from a nearby rock landfill and (3) dissolution of

  4. Implementation Strategies for Large-Scale Transport Simulations Using Time Domain Particle Tracking

    NASA Astrophysics Data System (ADS)

    Painter, S.; Cvetkovic, V.; Mancillas, J.; Selroos, J.

    2008-12-01

    Time domain particle tracking is an emerging alternative to the conventional random walk particle tracking algorithm. With time domain particle tracking, particles are moved from node to node on one-dimensional pathways defined by streamlines of the groundwater flow field or by discrete subsurface features. The time to complete each deterministic segment is sampled from residence time distributions that include the effects of advection, longitudinal dispersion, a variety of kinetically controlled retention (sorption) processes, linear transformation, and temporal changes in groundwater velocities and sorption parameters. The simulation results in a set of arrival times at a monitoring location that can be post-processed with a kernel method to construct mass discharge (breakthrough) versus time. Implementation strategies differ for discrete flow (fractured media) systems and continuous porous media systems. The implementation strategy also depends on the scale at which hydraulic property heterogeneity is represented in the supporting flow model. For flow models that explicitly represent discrete features (e.g., discrete fracture networks), the sampling of residence times along segments is conceptually straightforward. For continuous porous media, such sampling needs to be related to the Lagrangian velocity field. Analytical or semi-analytical methods may be used to approximate the Lagrangian segment velocity distributions in aquifers with low-to-moderate variability, thereby capturing transport effects of subgrid velocity variability. If variability in hydraulic properties is large, however, Lagrangian velocity distributions are difficult to characterize and numerical simulations are required; in particular, numerical simulations are likely to be required for estimating the velocity integral scale as a basis for advective segment distributions. Aquifers with evolving heterogeneity scales present additional challenges. Large-scale simulations of radionuclide

  5. Water and sediment transport modeling of a large temporary river basin in Greece.

    PubMed

    Gamvroudis, C; Nikolaidis, N P; Tzoraki, O; Papadoulakis, V; Karalemas, N

    2015-03-01

    The objective of this research was to study the spatial distribution of runoff and sediment transport in a large Mediterranean watershed (Evrotas River Basin) consisting of temporary flow tributaries and high mountain areas and springs by focusing on the collection and use of a variety of data to constrain the model parameters and characterize hydrologic and geophysical processes at various scales. Both monthly and daily discharge data (2004-2011) and monthly sediment concentration data (2010-2011) from an extended monitoring network of 8 sites were used to calibrate and validate the Soil and Water Assessment Tool (SWAT) model. In addition flow desiccation maps showing wet and dry aquatic states obtained during a dry year were used to calibrate the simulation of low flows. Annual measurements of sediment accumulation in two reaches were used to further calibrate the sediment simulation. Model simulation of hydrology and sediment transport was in good agreement with field observations as indicated by a variety of statistical measures used to evaluate the goodness of fit. A water balance was constructed using a 12 year long (2000-2011) simulation. The average precipitation of the basin for this period was estimated to be 903 mm yr(-1). The actual evapotranspiration was 46.9% (424 mm yr(-1)), and the total water yield was 13.4% (121 mm yr(-1)). The remaining 33.4% (302 mm yr(-1)) was the amount of water that was lost through the deep groundwater of Taygetos and Parnonas Mountains to areas outside the watershed and for drinking water demands (6.3%). The results suggest that the catchment has on average significant water surplus to cover drinking water and irrigation demands. However, the situation is different during the dry years, where the majority of the reaches (85% of the river network are perennial and temporary) completely dry up as a result of the limited rainfall and the substantial water abstraction for irrigation purposes. There is a large variability in the

  6. Sediment transport dynamics in response to large-scale human intervention

    NASA Astrophysics Data System (ADS)

    Eelkema, Menno; Wang, Zheng Bing

    2010-05-01

    SEDIMENT TRANSPORT DYNAMICS IN RESPONSE TO LARGE-SCALE HUMAN INTERVENTION M. Eelkema and Z.B. Wang The Eastern Scheldt basin in the southwestern part of the Netherlands is an elongated tidal basin of approximately 50 km in length with an average tidal range of roughly 3 meters at the inlet. Before 1969 A.D., this basin was also connected to two more tidal basins to the north through several narrow, yet deep channels. These connections were closed off with dams in the nineteen sixties in response to the catastrophic flooding in 1953. In the inlet of the Eastern Scheldt a storm-surge barrier was built in order to safeguard against flooding during storms while retaining a part of the tidal influence inside the basin during normal conditions. This barrier was finalized in 1986. The construction of the back-barrier dams in 1965 and 1969 had a significant impact on the tidal hydrodynamics and sediment transport (Van den Berg, 1986). The effects of these interventions were still ongoing when the hydrodynamic regime was altered again by the construction of the storm-surge barrier between 1983 and 1986. This research aims to describe the hydrodynamic and morphodynamic evolution of the Eastern Scheldt between 1953 and 1983, before construction of the storm-surge barrier had started. An analysis is made of the manner in which the back-barrier dams changed the tidal flow through the basin, and how these altered hydrodynamics influenced the sediment transport and morphology. This analysis consists first of all of a description of the observed hydrodynamical and bathymetrical changes. Second, these observations are used as input for a process-based hydrodynamic model (Delft3D), which is applied in order to gain more insight into the changes in sediment transport patterns. The model is used to simulate the situations before and after the closures of the connections between the Eastern Scheldt and the basins north of it In the decades before 1965, the Eastern Scheldt exported

  7. Electron collection theory for a D-region subsonic blunt electrostatic probe

    NASA Technical Reports Server (NTRS)

    Wai-Kwong Lai, T.

    1974-01-01

    Blunt probe theory for subsonic flow in a weakly ionized and collisional gas is reviewed, and an electron collection theory for the relatively unexplored case, Deybye length approximately 1, which occurs in the lower ionosphere (D-region), is developed. It is found that the dimensionless Debye length is no longer an electric field screening parameter, and the space charge field effect can be negelected. For ion collection, Hoult-Sonin theory is recognized as a correct description of the thin, ion density-perturbed layer adjacent the blunt probe surface. The large volume with electron density perturbed by a positively biased probe renders the usual thin boundary layer analysis inapplicable. Theories relating free stream conditions to the electron collection rate for both stationary and moving blunt probes are obtained. A model based on experimental nonlinear electron drift velocity data is proposed. For a subsonically moving probe, it is found that the perturbed region can be divided into four regions with distinct collection mechanisms.

  8. Aeroacoustic Data for a High Reynolds Number Axisymmetric Subsonic Jet

    NASA Technical Reports Server (NTRS)

    Ponton, Michael K.; Ukeiley, Lawrence S.; Lee, Sang W.

    1999-01-01

    The near field fluctuating pressure and aerodynamic mean flow characteristics of a cold subsonic jet issuing from a contoured convergent nozzle are presented. The data are presented for nozzle exit Mach numbers of 0.30, 0.60, and 0.85 at a constant jet stagnation temperature of 104 F. The fluctuating pressure measurements were acquired via linear and semi-circular microphone arrays and the presented results include plots of narrowband spectra, contour maps, streamwise/azimuthal spatial correlations for zero time delay, and cross-spectra of the azimuthal correlations. A pitot probe was used to characterize the mean flow velocity by assuming the subsonic flow to be pressure-balanced with the ambient field into which it exhausts. Presented are mean flow profiles and the momentum thickness of the free shear layer as a function of streamwise position.

  9. A study of sound generation in subsonic rotors, volume 2

    NASA Technical Reports Server (NTRS)

    Chalupnik, J. D.; Clark, L. T.

    1975-01-01

    Computer programs were developed for use in the analysis of sound generation by subsonic rotors. Program AIRFOIL computes the spectrum of radiated sound from a single airfoil immersed in a laminar flow field. Program ROTOR extends this to a rotating frame, and provides a model for sound generation in subsonic rotors. The program also computes tone sound generation due to steady state forces on the blades. Program TONE uses a moving source analysis to generate a time series for an array of forces moving in a circular path. The resultant time series are than Fourier transformed to render the results in spectral form. Program SDATA is a standard time series analysis package. It reads in two discrete time series and forms auto and cross covariances and normalizes these to form correlations. The program then transforms the covariances to yield auto and cross power spectra by means of a Fourier transformation.

  10. User's manual: Subsonic/supersonic advanced panel pilot code

    NASA Technical Reports Server (NTRS)

    Moran, J.; Tinoco, E. N.; Johnson, F. T.

    1978-01-01

    Sufficient instructions for running the subsonic/supersonic advanced panel pilot code were developed. This software was developed as a vehicle for numerical experimentation and it should not be construed to represent a finished production program. The pilot code is based on a higher order panel method using linearly varying source and quadratically varying doublet distributions for computing both linearized supersonic and subsonic flow over arbitrary wings and bodies. This user's manual contains complete input and output descriptions. A brief description of the method is given as well as practical instructions for proper configurations modeling. Computed results are also included to demonstrate some of the capabilities of the pilot code. The computer program is written in FORTRAN IV for the SCOPE 3.4.4 operations system of the Ames CDC 7600 computer. The program uses overlay structure and thirteen disk files, and it requires approximately 132000 (Octal) central memory words.

  11. Development of panel methods for subsonic analysis and design

    NASA Technical Reports Server (NTRS)

    Bristow, D. R.

    1980-01-01

    Two computer programs, developed for subsonic inviscid analysis and design are described. The first solves arbitrary mixed analysis design problems for multielement airfoils in two dimensional flow. The second calculates the pressure distribution for arbitrary lifting or nonlifting three dimensional configurations. In each program, inviscid flow is modelled by using distributed source doublet singularities on configuration surface panels. Numerical formulations and representative solutions are presented for the programs.

  12. Static aeroelastic behavior of a subsonic plate wing

    NASA Astrophysics Data System (ADS)

    Berci, M.

    2017-07-01

    The static aeroelastic behavior of a subsonic plate wing is here described by semi-analytical means. Within a generalised modal formulation, any distribution of the plate's properties is allowed. Modified strip theory is employed for the aerodynamic modelling and a linear aeroelastic model is eventually derived. Numerical results are then shown for the plate's aeroelastic stability in terms of divergence speed, with respect to the most relevant aero-structural parameters.

  13. Subsonic/transonic prediction capabilities for nozzle/afterbody configurations

    NASA Technical Reports Server (NTRS)

    Wilmoth, R. G.; Putnam, L. E.

    1984-01-01

    Prediction methods for several nozzle/afterbody flow problems at subsonic and transonic speeds are presented. These methods range from viscous-inviscid interaction methods to solutions for the Navier-Stokes equations in two and three dimensions. The problems addressed are the flow around isolated axisymmetric nozzles, isolated nonaxisymmetric nozzles, and axisymmetric nozzles with empennage. An assessment of the state of development of the methods via comparisons with experimental data is presented.

  14. Effect of Riblets upon Flow Separation in a Subsonic Diffuser

    DTIC Science & Technology

    1988-12-01

    Technology Air University In Partial Fulfillment of the Requirements for the Degree of Master of Science in Aeronautical Engineering Nathan W. Martens...afterburner where the flow leaving the turbine must be 4 slowed from a high subsonic Mach number to a Mach number of about 0.2" (8:305). Physicall ., a...Second Edition). New York: McGraw-Hill Book Company, 1975. 3. Cebeci, Tuncer and A. M. 0. Smith. Analysis of Turbulent Boundary Layers. Orlando: Academic

  15. Three dimensional supersonic flows with subsonic axial Mach numbers

    NASA Technical Reports Server (NTRS)

    Marconi, F.; Moretti, G.

    1976-01-01

    A numerical approach is presented for the computation of flows in which the component of velocity in the selected marching direction is subsonic although the total velocity is supersonic. A local coordinate rotation procedure is employed together with an implicit differencing scheme. Complex coordinate transformations and time-consuming iterations are avoided. The implementation of the described approach is illustrated with the aid of a two-dimensional problem. An application in the case of three-dimensional flows is also discussed.

  16. Advanced surface paneling method for subsonic and supersonic flow

    NASA Technical Reports Server (NTRS)

    Erickson, L. L.; Johnson, F. T.; Ehlers, F. E.

    1976-01-01

    Numerical results illustrating the capabilities of an advanced aerodynamic surface paneling method are presented. The method is applicable to both subsonic and supersonic flow, as represented by linearized potential flow theory. The method is based on linearly varying sources and quadratically varying doublets which are distributed over flat or curved panels. These panels are applied to the true surface geometry of arbitrarily shaped three dimensional aerodynamic configurations.

  17. Space transportation alternatives for large space programs - The International Space University summer session - 1992

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    1993-01-01

    The issues discussed in this paper are the result of a 10-week study by the Space Solar Power Program design project members and the Space Transportation Group at the International Space University (ISU) summer session of 1992 to investigate new paradigms in space propulsion and how those paradigms might reduce the costs for large space programs. The program plan was to place a series of power satellites in Earth orbit. Several designs were studied where many kW, MW or GW of power would be transmitted to Earth or to other spacecraft in orbit. During the summer session, a space solar power system was also detailed and analyzed. At ISU, the focus of the study was to foster and develop some of the new paradigms that may eliminate the barriers to low cost for space exploration and exploitation. Many international and technical aspects of a large multinational program were studied. Environmental safety, space construction and maintenance, legal and policy issues of frequency allocation, technology transfer and control and many other areas were addressed.

  18. Design description of the Large Coil Test Facility pulse-coil support and transport system

    SciTech Connect

    Queen, C.C.

    1981-01-01

    In order to simulate the transient fields which would be imposed on superconducting toroidal field coils in an operating tokamak reactor, the Large Coil Test Facility (LCTF) test stand includes a set of pulse coils. This set of pulse coils is designed to be moved from one test location to another within the LCTF vacuum vessel while the vessel is operating under vacuum and the test stand and test coils are at an operating temperature of 4.2K. This operating environment and the extremely high magnetic loads have necessitated some unique design features for the pulse coil support and transport system. The support structure for the pulse coil must react high overturning moments and axial loads induced on the pulse coil by the interaction of the pulse field with the field generated by the large test coils. These loads are reacted into the test stand support structure or spider frame by an arrangement of six pedestals and a support beam. In order to move the pulse coil set from one test location to another, the support beam containing the pulse coils must be driven across rollers mounted on the pedestals, then clamped securely to react the loads. Because these operations must be performed in a vacuum environment at cryogenic tmperature, special consideration was given to component design.

  19. Groundwater quality across scales: impact on nutrient transport to large water bodies

    NASA Astrophysics Data System (ADS)

    Dürr, Hans; Moosdorf, Nils; Mallast, Ulf

    2017-04-01

    High concentrations of dissolved nutrients such as nitrogen (N) and phosphorus (P) in groundwater are an increasing concern in many areas of the world. Especially regions with high agriculture impact see widespread declining groundwater quality, with considerable uncertainty mainly regarding the impact of phosphorus (P). Implications reach from direct impacts on different water users to discharge of nutrient-rich groundwater to rivers, lakes and coastal areas, where it can contribute to eutrophication, hypoxia or harmful algal blooms. While local-scale studies are abundant and management options exist, quantitative approaches at regional to continental scales are scarce and frequently have to deal with data inconsistencies or are temporally sparse. Here, we present the research framework to combine large databases of local groundwater quality to data sets of climatical, hydrological, geological or landuse parameters. Pooling of such information, together with robust methods such as water balances and groundwater models, can provide constraints such as upper boundaries and likely ranges of nutrient composition in various settings, or for the nutrient transport to large water bodies. Remote Sensing can provide spatial information on the location of groundwater seepage. Results will eventually help to identify focus areas and lead to improved understanding of the role of groundwater in the context of global biogeochemical cycles.

  20. Space transportation alternatives for large space programs - The International Space University summer session - 1992

    NASA Astrophysics Data System (ADS)

    Palaszewski, Bryan

    1993-06-01

    The issues discussed in this paper are the result of a 10-week study by the Space Solar Power Program design project members and the Space Transportation Group at the International Space University (ISU) summer session of 1992 to investigate new paradigms in space propulsion and how those paradigms might reduce the costs for large space programs. The program plan was to place a series of power satellites in Earth orbit. Several designs were studied where many kW, MW or GW of power would be transmitted to Earth or to other spacecraft in orbit. During the summer session, a space solar power system was also detailed and analyzed. At ISU, the focus of the study was to foster and develop some of the new paradigms that may eliminate the barriers to low cost for space exploration and exploitation. Many international and technical aspects of a large multinational program were studied. Environmental safety, space construction and maintenance, legal and policy issues of frequency allocation, technology transfer and control and many other areas were addressed.

  1. Tests and analyses applicable to passenger ride quality of large transport aircraft

    NASA Technical Reports Server (NTRS)

    Holloway, R. B.; Brumaghin, S. H.

    1972-01-01

    A test program was undertaken to determine airline passenger reaction to vibration environments that might be encountered in a supersonic transport or other large commercial jet aircraft. The principal problem addressed was to determine accelerations of vertical and lateral vibration that people find objectionable. Further questions experimentally posed were: (1) what is the relationship between human reactions to vertical and lateral vibration, (2) to single- and combined-frequency vibration, and (3) to single- and combined-axis vibration? Interest was confined to reactions to vibration in the frequency range of 0.20 to 7.0 Hz, a range typical of the vibration environment of a large airplane. Results indicated an increasing sensitivity to vertical vibration as frequency was increased from 1.0 to 7.0 Hz. Subjects were found most sensitive to lateral vibration in the 1.0 to 3.0 Hz range. There was a nearly linear decrease in sensitivity as frequency of lateral vibration was increased from 3.0 to 7.0 Hz.

  2. Space transportation alternatives for large space programs - The International Space University summer session - 1992

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan

    1993-01-01

    The issues discussed in this paper are the result of a 10-week study by the Space Solar Power Program design project members and the Space Transportation Group at the International Space University (ISU) summer session of 1992 to investigate new paradigms in space propulsion and how those paradigms might reduce the costs for large space programs. The program plan was to place a series of power satellites in Earth orbit. Several designs were studied where many kW, MW or GW of power would be transmitted to Earth or to other spacecraft in orbit. During the summer session, a space solar power system was also detailed and analyzed. At ISU, the focus of the study was to foster and develop some of the new paradigms that may eliminate the barriers to low cost for space exploration and exploitation. Many international and technical aspects of a large multinational program were studied. Environmental safety, space construction and maintenance, legal and policy issues of frequency allocation, technology transfer and control and many other areas were addressed.

  3. Demonstration of a Probabilistic Technique for the Determination of Economic Viability of Very Large Transport Configurations

    NASA Technical Reports Server (NTRS)

    Mavris, Dimitri N.

    1998-01-01

    Over the past few years, modem aircraft design has experienced a paradigm shift from designing for performance to designing for affordability. This report contains a probabilistic approach that will allow traditional deterministic design methods to be extended to account for disciplinary, economic, and technological uncertainty. The probabilistic approach was facilitated by the Fast Probability Integration (FPI) technique; a technique which allows the designer to gather valuable information about the vehicle's behavior in the design space. This technique is efficient for assessing multi-attribute, multi-constraint problems in a more realistic fashion. For implementation purposes, this technique is applied to illustrate how both economic and technological uncertainty associated with a Very Large Transport aircraft concept may be assessed. The assessment is evaluated with the FPI technique to determine the cumulative probability distributions of the design space, as bound by economic objectives and performance constraints. These distributions were compared to established targets for a comparable large capacity aircraft, similar in size to the Boeing 747-400. The conventional baseline configuration design space was determined to be unfeasible and marginally viable, motivating the infusion of advanced technologies, including reductions in drag, specific fuel consumption, wing weight, and Research, Development, Testing, and Evaluation costs. The resulting system design space was qualitatively assessed with technology metric "k" factors. The infusion of technologies shifted the VLT design into regions of feasibility and greater viability. The study also demonstrated a method and relationship by which the impact of new technologies may be assessed in a more system focused approach.

  4. Sensitivity of morphometric estimates of sediment transport in large gravel-bed rivers

    NASA Astrophysics Data System (ADS)

    Brasington, James; Langham, Joseph; Rumsby, Barbara

    2002-01-01

    The estimation of fluvial sediment transport rate from measurements of morphological change has received growing recent interest in the last five years. The revival of the 'morphological method' reflects continuing concern over traditional methods of rate determination but also the availability of new survey methods capable of high-precision, high-resolution topographic monitoring. In particular, remote sensing of river channels through aerial digital photogrammetry is a potentially attractive alternative to labor intensive ground surveys. However, while photogrammetry presents the opportunity to acquire survey data over large areas, data precision and accuracy, particularly in the vertical dimension is lower than traditional ground survey methods. This paper presents results of recent research in which DEMs have been developed for a reach of a large braided gravel bed river in Scotland using both digital photogrammetry and high resolution RTK GPS ground surveys. For both approaches, a statistical level of detection of change is assessed by intercomparing surfaces with independent check points. The sensitivity of the annual channel sediment budget to this level of detection is presented. Preliminary results suggest that as much as 60% of channel deposition and 30% of erosion may be obscured by the lower level of precision associated with photogrammetric monitoring.

  5. Fuzzy-rule based metamodeling of nitrate transport in large catchments

    NASA Astrophysics Data System (ADS)

    van der Heijden, S.; Haberlandt, U.

    2012-04-01

    Especially for nutrient balance simulations, physically based ecohydrological modeling needs an abundance of measured data and model parameters, which for large catchments all too often are not available in sufficient spatial or temporal resolution or are simply unknown. For efficient large-scale studies it is thus beneficial to have methods at one's disposal which are parsimonious concerning the number of model parameters and the necessary input data. One such method is fuzzy-rule based modeling, which compared to other machine-learning techniques has the advantages to produce models (the fuzzy-rules) which are physically interpretable to a certain extent, and to allow the explicit introduction of expert knowledge through pre-defined rules. The study focuses on the application of fuzzy-rule based modeling for nitrate transport simulation in large catchments, in particular concerning decision support. To be able to construct such models it is possible to take a well-calibrated physically based model to produce data. This metamodeling approach replaces missing observed data. Thus, in a first step the ecohydrological model SWAT was calibrated for a 1000 km2 study area in Northern Germany and used to produce the needed data for rule training. Taking into account the different pathways of nitrate emission from soils (surface runoff, interflow, leaching to groundwater), a modular setup was chosen for the fuzzy model. Two modules were created for each pathway, one for the calculation of fertilized soils and one for non-fertilized soils. Adding one module for groundwater and one for river runoff yields a model consisting of eight modules in total. After selection of appropriate input variables (seven to nine variables for each module) the modules were trained using the SWAT data and simulated annealing as a discrete optimization method. Although flow components are of major importance when describing nitrate transport, they also imply a dependence on (deterministic) water

  6. Subsonic Flow for the Multidimensional Euler-Poisson System

    NASA Astrophysics Data System (ADS)

    Bae, Myoungjean; Duan, Ben; Xie, Chunjing

    2016-04-01

    We establish the existence and stability of subsonic potential flow for the steady Euler-Poisson system in a multidimensional nozzle of a finite length when prescribing the electric potential difference on a non-insulated boundary from a fixed point at the exit, and prescribing the pressure at the exit of the nozzle. The Euler-Poisson system for subsonic potential flow can be reduced to a nonlinear elliptic system of second order. In this paper, we develop a technique to achieve a priori {C^{1,α}} estimates of solutions to a quasi-linear second order elliptic system with mixed boundary conditions in a multidimensional domain enclosed by a Lipschitz continuous boundary. In particular, we discovered a special structure of the Euler-Poisson system which enables us to obtain {C^{1,α}} estimates of the velocity potential and the electric potential functions, and this leads us to establish structural stability of subsonic flows for the Euler-Poisson system under perturbations of various data.

  7. Treatment of large bone defects with a novel biological transport disc in non-vascular transport distraction osteogenesis.

    PubMed

    Zeng, J J; Guo, P; Zhou, N; Xie, Q T; Liao, F C

    2016-05-01

    The aim of this study was to investigate a potential novel biological transport disc that avoids secondary injury to the body and facilitates bone healing. Twenty-seven dogs were divided randomly into three groups: group A were treated with human bone morphogenetic protein 2 (BMP-2) modified bone mesenchymal stem cell (BMSC) sheets combined with freeze-dried bone allograft as biological transport disc; group B were treated with BMSC sheets combined with freeze-dried bone allograft as transport disc (control); and group C were treated with direct extension only (blank). There were nine dogs in each group. Non-vascular transport distraction osteogenesis was performed in groups A and B to repair the mandibular bone defects, and in group C only mandibular truncation surgery was performed. The regeneration of bone was evaluated through X-ray, haematoxylin and eosin assay, and immunohistochemistry. After 2, 4, and 8 weeks of distraction, new bone density values in group A were 49.00±1.16, 66.63±2.62, and 72.78±2.67, respectively, and these were significantly different to values in groups B (P=0.0005, P=0.0004, P=0.0012) and C (P<0.0005, P=0.0001, P=0.0003). The average grey value for BMP-2 expression in group A after 4 weeks of distraction was 195.63±4.45, which was significantly different when compared to groups B (P=0.0022) and C (P=0.0006). This novel biological transport disc represents an effective non-secondary injury method to enhance new bone formation in non-vascular transport distraction osteogenesis.

  8. Test-to-Test Repeatability of Results From a Subsonic Wing-Body Configuration in the National Transonic Facility

    NASA Technical Reports Server (NTRS)

    Mineck, Raymond E.; Pendergraft, Odis C., Jr.

    2000-01-01

    Results from three wind tunnel tests in the National Transonic Facility of a model of an advanced-technology, subsonic-transport wing-body configuration have been analyzed to assess the test-to-test repeatability of several aerodynamic parameters. The scatter, as measured by the prediction interval, in the longitudinal force and moment coefficients increases as the Mach number increases. Residual errors with and without the ESP tubes installed suggest a bias leading to lower drag with the tubes installed. Residual errors as well as average values of the longitudinal force and moment coefficients show that there are small bias errors between the different tests.

  9. Transport, retention, and ecological significance of woody debris within a large ephemeral river

    USGS Publications Warehouse

    Jacobson, P.J.; Jacobson, K.M.; Angermeier, P.L.; Cherry, D.S.

    1999-01-01

    The spatiotemporal patterns and ecological significance of the retention of coarse particulate organic matter and large woody debris have been intensively studied in perennial rivers and streams but are virtually unknown in ephemeral systems. We examined the influence of 2 features characteristic of ephemeral systems, downstream hydrologic decay and in-channel tree growth, on the distribution, transport, and retention of woody debris following a flood having a ~2.6-y recurrence interval in the ephemeral Kuiseb River in southwestern Africa. A total of 2105 pieces of wood were painted at 8 sites along the river channel to measure retention patterns. The flood had a peak discharge of 159 m3/s at the upper end of the study area, decaying to <1 m3/s by 200 km downstream. Downstream export of wood from marking sites totaled 59.5% (n = 1253). Transport distances ranged from 1 to 124 km, and 34.8% (n = 436) of the exported wood was recovered. Marked wood retained within marking sites was significantly longer than exported wood (p < 0.001, t-test). Once in transport, there was little correlation between wood length and distance traveled (r = 0.11, correlation analysis, n = 369). Length influenced the site of retention; material retained on debris piles was significantly longer than that stranded on channel sediments (p < 0.001, t-test). In-channel growth of Faidherbia trees significantly influenced wood retention; 83.7% of marked wood not moved by the flood was associated with debris piles on Faidherbia trees. Similarly, 65% of the exported wood retained within downstream debris piles was associated with Faidherbia trees. In contrast to many perennial systems, we observed a general increase in wood retention downstream, peaking in the river's lower reaches in response to hydrologic decay. Debris piles induced sediment deposition and the formation of in-channel islands. Following flood recession, debris piles and their associated sediments provided moist, organic

  10. Investigating convective transport processes and large scale stratospheric dynamics with ICON-ART

    NASA Astrophysics Data System (ADS)

    Stassen, Christian; Ruhnke, Roland; Schröter, Jennifer; Daniel, Rieger; Bischoff-Gauss, Ingeborg; Vogel, Heike; Vogel, Bernhard

    2015-04-01

    We have extended the global ICON (ICOsahedral Nonhydrostatic) modelling framework. ICON is a joint development by the German Weather Service (DWD) and the Max-Planck-Institute for Meteorology (MPI-M). We added modules for gas-phase chemistry and aerosol dynamics (ART, Aerosols and Reactive Trace gases) [1]. ICON allows a regional grid refinement with two-way interactions between the different horizontal grids. It is used by DWD for numerical weather predictions and will be used by MPI-M for climate projections [2]. The extended modelling framework ICON-ART is developed in an analogous way to its predecessors COSMO-ART [3], so that aerosol and chemical composition feedbacks can be considered in a comprehensive way. Up to now, ICON-ART accounts for volcanic ash tracers, radioactive tracers, sea salt and mineral dust aerosols. Additionally, several gaseous tracers have been introduced. For the dynamics (transport and diffusion) of aerosol and gaseous tracers, the original ICON tracer framework is used. For the model physics, numerical time integration follows a process splitting approach separating physical processes. Each process is called independently via an interface module. Currently, the processes of emission, dry and wet deposition, sedimentation, and first order chemical reactions are included. We will present a simulation of the transport of ozone depleting short-lived trace gases from the surface into the stratosphere as well as of long-lived tracers. The simulated tracer distributions are used to investigate the ability of ICON-ART to simulate convective vertical transport in the troposphere as well as of large-scale stratospheric dynamics. [1] Rieger, D., et al. (2014), ICON-ART - A new online-coupled model system from the global to regional scale, submitted to Geosci. Model Dev. [2] Zängl, G., et al. (2014), The ICON (ICOsahedral Non-hydrostatic) modelling framework of DWD MPI-M: Description of the non-hydrostatic dynamical core. Q.J.R. Meteorol. Soc

  11. Large-Scale Transport Model Uncertainty and Sensitivity Analysis: Distributed Sources in Complex, Hydrogeologic Systems

    NASA Astrophysics Data System (ADS)

    Wolfsberg, A.; Kang, Q.; Li, C.; Ruskauff, G.; Bhark, E.; Freeman, E.; Prothro, L.; Drellack, S.

    2007-12-01

    The Underground Test Area (UGTA) Project of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office is in the process of assessing and developing regulatory decision options based on modeling predictions of contaminant transport from underground testing of nuclear weapons at the Nevada Test Site (NTS). The UGTA Project is attempting to develop an effective modeling strategy that addresses and quantifies multiple components of uncertainty including natural variability, parameter uncertainty, conceptual/model uncertainty, and decision uncertainty in translating model results into regulatory requirements. The modeling task presents multiple unique challenges to the hydrological sciences as a result of the complex fractured and faulted hydrostratigraphy, the distributed locations of sources, the suite of reactive and non-reactive radionuclides, and uncertainty in conceptual models. Characterization of the hydrogeologic system is difficult and expensive because of deep groundwater in the arid desert setting and the large spatial setting of the NTS. Therefore, conceptual model uncertainty is partially addressed through the development of multiple alternative conceptual models of the hydrostratigraphic framework and multiple alternative models of recharge and discharge. Uncertainty in boundary conditions is assessed through development of alternative groundwater fluxes through multiple simulations using the regional groundwater flow model. Calibration of alternative models to heads and measured or inferred fluxes has not proven to provide clear measures of model quality. Therefore, model screening by comparison to independently-derived natural geochemical mixing targets through cluster analysis has also been invoked to evaluate differences between alternative conceptual models. Advancing multiple alternative flow models, sensitivity of transport predictions to parameter uncertainty is assessed through Monte Carlo simulations. The

  12. Large-Scale Transport Model Uncertainty and Sensitivity Analysis: Distributed Sources in Complex Hydrogeologic Systems

    SciTech Connect

    Sig Drellack, Lance Prothro

    2007-12-01

    The Underground Test Area (UGTA) Project of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office is in the process of assessing and developing regulatory decision options based on modeling predictions of contaminant transport from underground testing of nuclear weapons at the Nevada Test Site (NTS). The UGTA Project is attempting to develop an effective modeling strategy that addresses and quantifies multiple components of uncertainty including natural variability, parameter uncertainty, conceptual/model uncertainty, and decision uncertainty in translating model results into regulatory requirements. The modeling task presents multiple unique challenges to the hydrological sciences as a result of the complex fractured and faulted hydrostratigraphy, the distributed locations of sources, the suite of reactive and non-reactive radionuclides, and uncertainty in conceptual models. Characterization of the hydrogeologic system is difficult and expensive because of deep groundwater in the arid desert setting and the large spatial setting of the NTS. Therefore, conceptual model uncertainty is partially addressed through the development of multiple alternative conceptual models of the hydrostratigraphic framework and multiple alternative models of recharge and discharge. Uncertainty in boundary conditions is assessed through development of alternative groundwater fluxes through multiple simulations using the regional groundwater flow model. Calibration of alternative models to heads and measured or inferred fluxes has not proven to provide clear measures of model quality. Therefore, model screening by comparison to independently-derived natural geochemical mixing targets through cluster analysis has also been invoked to evaluate differences between alternative conceptual models. Advancing multiple alternative flow models, sensitivity of transport predictions to parameter uncertainty is assessed through Monte Carlo simulations. The

  13. Porous medium convection at large Rayleigh number: Studies of coherent structure, transport, and reduced dynamics

    NASA Astrophysics Data System (ADS)

    Wen, Baole

    Buoyancy-driven convection in fluid-saturated porous media is a key environmental and technological process, with applications ranging from carbon dioxide storage in terrestrial aquifers to the design of compact heat exchangers. Porous medium convection is also a paradigm for forced-dissipative infinite-dimensional dynamical systems, exhibiting spatiotemporally chaotic dynamics if not "true" turbulence. The objective of this dissertation research is to quantitatively characterize the dynamics and heat transport in two-dimensional horizontal and inclined porous medium convection between isothermal plane parallel boundaries at asymptotically large values of the Rayleigh number Ra by investigating the emergent, quasi-coherent flow. This investigation employs a complement of direct numerical simulations (DNS), secondary stability and dynamical systems theory, and variational analysis. The DNS confirm the remarkable tendency for the interior flow to self-organize into closely-spaced columnar plumes at sufficiently large Ra (up to Ra ≃ 105), with more complex spatiotemporal features being confined to boundary layers near the heated and cooled walls. The relatively simple form of the interior flow motivates investigation of unstable steady and time-periodic convective states at large Ra as a function of the domain aspect ratio L. To gain insight into the development of spatiotemporally chaotic convection, the (secondary) stability of these fully nonlinear states to small-amplitude disturbances is investigated using a spatial Floquet analysis. The results indicate that there exist two distinct modes of instability at large Ra: a bulk instability mode and a wall instability mode. The former usually is excited by long-wavelength disturbances and is generally much weaker than the latter. DNS, strategically initialized to investigate the fully nonlinear evolution of the most dangerous secondary instability modes, suggest that the (long time) mean inter-plume spacing in

  14. Dynamics of sediment transport in large tropical tidal rivers via observations in the Mekong and Amazon

    NASA Astrophysics Data System (ADS)

    Nowacki, D. J.; Ogston, A. S.; Nittrouer, C. A.; Fricke, A. T.; Van, P.; Souza Filho, P. W.; Silva, M. S.

    2013-12-01

    Of the ten largest-discharge river systems worldwide, freshwater delivery to the ocean from tropical rivers comprises approximately 72% of the total. Tropical-river suspended-sediment loads make up about 45% of the total among the same ten largest rivers. In this context, flow and sediment dynamics of tropical river systems are crucial to a comprehensive understanding of global river budgets. The processes by which sediment is eroded, transported, trapped, and ultimately exported from tidal rivers--where tides propagate but oceanic salinity is absent or only ephemerally present--are poorly understood, even though previous research suggests up to one-third of riverine sediment loads may be trapped within tidal rivers. In an effort to better understand these processes, we present and contrast results from several campaigns along two large tropical tidal rivers: the Mekong and Amazon. Under conditions of high and low seasonal discharge, three cross-sections within the Mekong tidal river were each occupied for a 25-hour tidal cycle, during which ADCP and CTD transects were completed every 15-30 minutes. In this transitional environment between fluvial and estuarine conditions, flow reversed throughout the water column during both low and high flow at all locations, and a strongly sheared flow was present during lesser flood tides. Salinity was spatially variable over seasons: during low flow, salinity in excess of 10 PSU was observed 30 km upstream during maximum flood, while at the same location during high flow, salinity was less than 0.5 PSU at all times. Conditions were partially stratified during low flow. When present, stratification was in the form of a salt wedge during high flow. Suspended sediment was well mixed or exhibited a Rouse-like profile in fresh regions; suspended-sediment concentration within the salt wedge was generally less, except during periods of strong near-bottom flow within the salt-wedge water mass. During both seasons and at all locations

  15. Dominant-negative myosin Va impairs retrograde but not anterograde axonal transport of large dense core vesicles.

    PubMed

    Bittins, Claudia Margarethe; Eichler, Tilo Wolf; Hammer, John A; Gerdes, Hans-Hermann

    2010-04-01

    Axonal transport of peptide and hormone-containing large dense core vesicles (LDCVs) is known to be a microtubule-dependent process. Here, we suggest a role for the actin-based motor protein myosin Va specifically in retrograde axonal transport of LDCVs. Using live-cell imaging of transfected hippocampal neurons grown in culture, we measured the speed, transport direction, and the number of LDCVs that were labeled with ectopically expressed neuropeptide Y fused to EGFP. Upon expression of a dominant-negative tail construct of myosin Va, a general reduction of movement in both dendrites and axons was observed. In axons, it was particularly interesting that the retrograde speed of LDCVs was significantly impaired, although anterograde transport remained unchanged. Moreover, particles labeled with the dominant-negative construct often moved in the retrograde direction but rarely in the anterograde direction. We suggest a model where myosin Va acts as an actin-dependent vesicle motor that facilitates retrograde axonal transport.

  16. Heat transport and dynamics of the large-scale circulation of turbulent Rayleigh-Benard convection

    NASA Astrophysics Data System (ADS)

    Brown, Eric

    Experimental studies of turbulent Rayleigh-Benard convection in cylindrical water-filled containers of equal height and diameter, with an applied vertical temperature difference DeltaT are presented. High-precision measurements of the heat flux Q were shown to agree with the Grossman-Lohse (GL) scaling model of thermal convection for small DeltaT, but for large DeltaT a regime was reached where Q ∝ DeltaT 1/3 in disagreement with the GL model. A prediction that the heat transport in the fluid would be reduced for endplates with finite conductivity was confirmed by switching out plates with different thermal conductivities. The effect of the spatial variation of fluid properties with temperature was measured by comparing experiments in samples of different sizes with the same dimensionless control parameters but different DeltaT. Thermistors on the sidewall were used to measure various aspects of the large-scale circulation (LSC). The turnover and an azimuthally twisting oscillatory mode were found to have the same frequency for small DeltaT which agrees with the GL model, but the frequencies were found to differ from each other and from the GL model for large DeltaT. The azimuthal orientation theta0(t) of the LSC was found to meander in time as a diffusive process over long time scales. In addition it contained spontaneous events in which the orientation changed by a large angle Deltatheta, either by a rotation of the circulation plane, or by a cessation of the circulation followed by a restart in a randomly chosen direction as seen by the uniform probability distribution p(Deltatheta). Rotations occurred with a monotonically decreasing p(Deltatheta). The distribution of rotations and cessations in time followed Poissonian statistics. Also presented is a model of the dynamics of the LSC consisting of a pair of stochastic differential equations motivated by the Navier-Stokes equations. The equations have terms representing buoyancy, drag, and angular momentum of

  17. Tropical hornbills (Aceros cassidix, Aceros undulatus, and Buceros hydrocorax) use ballistic transport to feed with their large beaks.

    PubMed

    Baussart, Sabine; Bels, Vincent

    2011-02-01

    The most common and plesiomorphic mechanism of food transport in tetrapods is lingual-based. Neognathous birds use this mechanism for exploiting a large diversity of food resources, whereas paleognathous birds use cranioinertial mechanism with or without tongue involvement. Food transport in three hornbills' species (Aceros cassidix, A. undulatus, and Buceros hydrocorax) is defined by a ballistic transport mechanism. Only one transport cycle is used for moving the food from the tip of the beak to the pharynx. The tongue never makes contact with the food nor is it used to expand the buccal cavity. In hornbills, filmed through high-speed video, time to food release occurred between 0.11 and 0.16 sec before time to maximum gape. The ballistic curves show similar patterns. Maximum gape angle is significantly different between the three species. Each species show a different kinematic and motor pattern of head movements associated with ballistic transport. In A. undulatus, head rotation follows a continuous pattern similar to that reported earlier in toucans. A. cassidix rotates head downward at the time of maximum gape to permit food to reach the pharynx without touching the mandible. B. hydrocorax elevates the head along the transport cycle to avoid contact with the food to the cavity of the upper beak. Selection of large food items in the diet may explain the evolutionary trend of using ballistic transport in the feeding behavior of hornbills, which play a key role in tropical forest ecology by dispersing seeds.

  18. Large-scale bedforms as indicators of mutually evasive sand transport and the sequential infilling of wide-mouthed estuaries

    NASA Astrophysics Data System (ADS)

    Harris, Peter T.

    1988-06-01

    Large-scale bedforms (2-10 m in vertical and 10 2-10 3 m in horizontal dimensions) found in wide-mouthed estuaries are described. Different bedform types occur depending upon the local availability of sand. With an increasing sand supply, sand ribbons grade into elongate trains of sand waves and then form sandwave fields. Inshore, headland-associated sand banks are formed which multiply into en-echelon sand banks. Based upon a review of data on directions of sand transport from the Bristol Channel and Thames Estuary, U.K., and from Moreton Bay, Australia, charts of ebb- and flood-dominant transport zones are constructed for lower estuarine environments which have undergone different degrees of infilling. Linear sand banks are seen to delimit partially the boundaries between opposing sand transport zones. Transport paths demonstrate how sediments derived from outside of the estuary are dispersed through ebb and flood transport zones, to supply other areas of net deposition. A comparison between different estuaries reveals that variations in the compexity of ebb- and flood-dominant transport zones and the morphologies of large-scale bedforms are coupled with apparent changes in the relative amounts of sand available to each system. A model for the sequential infilling of estuaries and the evolution of large-scale bedforms is presented and applied to the interpretation of present day examples. Vertical sequences predicted to be generated by such bedform evolution are described and discussed, in terms of their preservation in the geological record.

  19. Large Eddy Simulation and Field Experiments of Pollen Transport in the Atmospheric Boundary Layer

    NASA Astrophysics Data System (ADS)

    Chamecki, M.; Meneveau, C.; Parlange, M. B.; van Hout, R.

    2006-12-01

    Dispersion of airborne pollen by the wind has been a subject of interest for botanists and allergists for a long time. More recently, the development of genetically modified crops and questions about cross-pollination and subsequent contamination of natural plant populations has brought even more interest to this field. A critical question is how far from the source field pollen grains will be advected. Clearly the answer depends on the aerodynamic properties of the pollen, geometrical properties of the field, topography, local vegetation, wind conditions, atmospheric stability, etc. As a consequence, field experiments are well suited to provide some information on pollen transport mechanisms but are limited to specific field and weather conditions. Numerical simulations do not have this drawback and can be a useful tool to study pollen dispersal in a variety of configurations. It is well known that the dispersion of particles in turbulent fields is strongly affected by the large scale coherent structures. Large Eddy Simulation (LES) is a technique that allows us to study the typical distances reached by pollen grains and, at the same time, resolve the larger coherent structures present in the atmospheric boundary layer. The main objective of this work is to simulate the dispersal of pollen grains in the atmospheric surface layer using LES. Pollen concentrations are simulated by an advection-diffusion equation including gravitational settling. Of extreme importance is the specification of the bottom boundary conditions characterizing the pollen source over the canopy and the deposition process everywhere else. In both cases we make use of the theoretical profile for suspended particles derived by Kind (1992). Field experiments were performed to study the applicability of the theoretical profile to pollen grains and the results are encouraging. Airborne concentrations as well as ground deposition from the simulations are compared to experimental data to validate the

  20. Theoretical prediction of nonlinear propagation effects on noise signatures generated by subsonic or supersonic propeller or rotor-blade tips

    NASA Technical Reports Server (NTRS)

    Barger, R. L.

    1980-01-01

    The nonlinear propagation equations for sound generated by a constant speed blade tip are presented. Propagation from a subsonic tip is treated as well as the various cases that can occur at supersonic speeds. Some computed examples indicate that the nonlinear theory correlates with experimental results better than linear theory for large amplitude waves. For swept tips that generate a wave with large amplitude leading expansion, the nonlinear theory predicts a cancellation effect that results in a significant reduction of both amplitude and impulse.

  1. Integrating the Chemical Fluxes of Transported Sediments in Large Rivers: AN Attempt on the Ganga

    NASA Astrophysics Data System (ADS)

    France-Lanord, C.; Lupker, M.; Lavé, J.; Bouchez, J.; Galy, V.; Gaillardet, J.; Metivier, F.

    2010-12-01

    Large rivers are the main conveyors of continental material to the oceans through sediment and dissolved fluxes. The redistribution of elements is fundamental in Earth surface processes and central in various biogeochemical cycles. The nature of the exported continental material is a function of the processes operating in the river’s catchment. From external forcings such as climate, tectonics or anthropogenic activity, having a strong control on erosion and weathering, to transport dynamics and sediment storage in flood plain, chemical elements are segregated from source to sink. Evaluating the composition of the exported sediments is thus essential in our understanding of large scale processes. This raises the problem of integrating the sediments chemical composition both spatially in a river section and temporally during the hydrogram. Efforts have been made to precisely determine de total flux of transported material of major world rivers but the determination of associated chemical solid fluxes is still limited. Also it is now recognized that surface sediments composition does not reflect in most cases the average sediment composition (Galy et al. 2007; Bouchez et al. in press). Nevertheless, global chemical budgets still rely on simple averaging of the available data counting mainly on surface sediment samples. Hydrodynamic sorting of minerals exerts a first order control on the chemistry of sediments in the water column, segregating elements according to the flow dynamics and the water depth. This has to be accounted for in order to derive accurate chemical fluxes. This work is an attempt to integrate the chemical flux of the sediments transported by the Ganga. The river was sampled at various stages of the monsoon at the same location in Bangladesh between 2004 and 2010 using a point sampler to collect sediments throughout the water column. Sediments were analyzed for major elements and grain-size. The systematic use of Acoustic Doppler Current Profilers

  2. Study of Flow, Turbulence and Transport on the Large Plasma Device

    NASA Astrophysics Data System (ADS)

    Schaffner, David Andrew

    The relationships amongst azimuthal flow, radial particle transport and turbulence on the Large Plasma Device (LAPD) are explored through the use of biasable limiters which continuously modify the rotation of the plasma column. Four quarter annulus plates serve as an iris-like boundary between the cathode source and the main plasma chamber. Application of a voltage to the plates using a capacitor bank drives cross-field current which rotates the plasma azimuthally in the electron diamagnetic direction (EDD). With the limiters inserted, a spontaneous rotation in the ion diamagnetic direction is observed; thus, increasing biasing tends to first slow rotation, null it out, then reverse it. This experiment builds on previous LAPD biasing experiments which used the chamber wall as the biasing electrode rather than inserted limiter plates. The use of inserted limiter biasing rather than chamber wall biasing allows for better cross-field current penetration between the plasma source and the electrodes which in turn allow for a finer variation of applied torque on the plasma. The modification of plasma parameter profiles, turbulent characteristics, and radial transport are tracked through these varying flow states. Azimuthal flow radial profiles are peaked at the limiter edge. Consequently, the variation in flow states also results in variation of sheared flow. Improved radial particle confinement is observed in states with sheared flow regardless of the direction of rotation. This improvement is indicated by both steepened density profiles and decreased radial particle flux. Conversely, a confinement degradation is seen in the minimum sheared flow state. Comparison of density fluctuation power and crossphase between density and radial velocity fluctuations show that both quantities are suppressed by sheared flow, but that the density fluctuation suppression is dominant and contributes most to the decrease in radial particle flux. Also, some observed changes to density and

  3. Making the transition to large scale ethanol use in the US Transportation Sector

    SciTech Connect

    McNutt, B.; Bergeron, P.; Singh, M.; Stork, K.

    1996-04-01

    A recent US Department of Energy study indicates that under current conditions (e.g., taxes) cellulosic ethanol could be one of the key fuels used to achieve the 30% replacement fuel goals of the US Energy Policy Act, as well as significant reductions in greenhouse gas emissions from transportation. However, the study also concludes that transition costs and issues could be significant and need to be evaluated. This paper examines (a) the costs and issues associated with ethanol use in various submarkets and how these costs will affect market penetration and (b) the costs and issues resulting from ethanol production from alternative feedstocks and their effect on the likely penetration of various feedstocks. The paper concludes that: technical opportunities exist to make major transitions in ethanol end-use and production; the end use transition has few and relatively small hurdles; the transition in feedstocks and production faces more significant technological and investment hurdles; but continued low gasoline prices are such that policy stimuli will be needed to start the transition to large scale ethanol use and may be required to maintain a growing market.

  4. A case study of chlorine transport and fate following a large accidental release

    NASA Astrophysics Data System (ADS)

    Buckley, Robert L.; Hunter, Charles H.; Werth, David W.; Whiteside, Morgana T.; Chen, Kuo-Fu; Mazzola, Carl A.

    2012-12-01

    A train derailment that occurred in Graniteville, South Carolina during the early morning hours of 06 January, 2005 resulted in the prompt release of approximately 60 tons of chlorine to the environment. Comprehensive modeling of the transport and fate of this release was performed including the characterization of the initial three-phased chlorine release, a detailed determination of the local atmospheric conditions acting to generate, disperse, and deplete the chlorine vapor cloud, the establishment of physical exchange mechanisms between the airborne vapor and local surface waters, and local aquatic dilution and mixing.Previous studies of large chlorine releases have concluded that depletion of the resulting vapor cloud through physical and chemical reactions with sunlight, atmospheric constituents, and local surfaces can significantly reduce the areal extent over which the vapor poses a toxicological hazard. For Graniteville, modeling results were the most consistent with available data on human health effects, animal and fish mortality, and vegetation damage when an effective deposition velocity in the lower end of a range of values commonly cited in other studies (1 cm s-1) was applied. This relatively small deposition is attributed to a lack of sunlight, a limited uptake in vegetation due to rapid stomatal damage, and the limited presence of nearby man-made structures. Explicit simulations of chlorine deposition into adjacent surface waters were based on a modified Henry's Law approach and resulted in the transfer of an estimated 21 kg of chlorine into these waters.

  5. Pure crystal orientation and anisotropic charge transport in large-area hybrid perovskite films

    PubMed Central

    Cho, Namchul; Li, Feng; Turedi, Bekir; Sinatra, Lutfan; Sarmah, Smritakshi P.; Parida, Manas R.; Saidaminov, Makhsud I.; Murali, Banavoth; Burlakov, Victor M.; Goriely, Alain; Mohammed, Omar F.; Wu, Tom; Bakr, Osman M.

    2016-01-01

    Controlling crystal orientations and macroscopic morphology is vital to develop the electronic properties of hybrid perovskites. Here we show that a large-area, orientationally pure crystalline (OPC) methylammonium lead iodide (MAPbI3) hybrid perovskite film can be fabricated using a thermal-gradient-assisted directional crystallization method that relies on the sharp liquid-to-solid transition of MAPbI3 from ionic liquid solution. We find that the OPC films spontaneously form periodic microarrays that are distinguishable from general polycrystalline perovskite materials in terms of their crystal orientation, film morphology and electronic properties. X-ray diffraction patterns reveal that the film is strongly oriented in the (112) and (200) planes parallel to the substrate. This film is structurally confined by directional crystal growth, inducing intense anisotropy in charge transport. In addition, the low trap-state density (7.9 × 1013 cm−3) leads to strong amplified stimulated emission. This ability to control crystal orientation and morphology could be widely adopted in optoelectronic devices. PMID:27830694

  6. Pure crystal orientation and anisotropic charge transport in large-area hybrid perovskite films

    NASA Astrophysics Data System (ADS)

    Cho, Namchul; Li, Feng; Turedi, Bekir; Sinatra, Lutfan; Sarmah, Smritakshi P.; Parida, Manas R.; Saidaminov, Makhsud I.; Murali, Banavoth; Burlakov, Victor M.; Goriely, Alain; Mohammed, Omar F.; Wu, Tom; Bakr, Osman M.

    2016-11-01

    Controlling crystal orientations and macroscopic morphology is vital to develop the electronic properties of hybrid perovskites. Here we show that a large-area, orientationally pure crystalline (OPC) methylammonium lead iodide (MAPbI3) hybrid perovskite film can be fabricated using a thermal-gradient-assisted directional crystallization method that relies on the sharp liquid-to-solid transition of MAPbI3 from ionic liquid solution. We find that the OPC films spontaneously form periodic microarrays that are distinguishable from general polycrystalline perovskite materials in terms of their crystal orientation, film morphology and electronic properties. X-ray diffraction patterns reveal that the film is strongly oriented in the (112) and (200) planes parallel to the substrate. This film is structurally confined by directional crystal growth, inducing intense anisotropy in charge transport. In addition, the low trap-state density (7.9 × 1013 cm-3) leads to strong amplified stimulated emission. This ability to control crystal orientation and morphology could be widely adopted in optoelectronic devices.

  7. Acoustic and Laser Doppler Anemometer Results for Confluent and 12-Lobed E(exp 3) Mixer Exhaust Systems for Subsonic Jet Noise Reduction

    NASA Technical Reports Server (NTRS)

    Salikuddin, M.; Babbit, R. R.; Shin, H.; Wisler, S.; Janardan, B. A.; Majjigi, R. K.; Bridges, James (Technical Monitor)

    2002-01-01

    The research described in this report has been funded by NASA Glenn Research Center as part of the Advanced Subsonic Technologies (AST) initiative. The program operates under the Large Engine Technologies (LET) as Task Order #3 1. Task Order 31 is a three year research program divided into three subtasks. Subtask A develops the experimental acoustic and aerodynamic subsonic mixed flow exhaust system databases. Subtask B seeks to develop and assess CFD-based aero-acoustic methods for subsonic mixed flow exhaust systems. Subtask B relies on the data obtained from Subtask A to direct and calibrate the aero-acoustic methods development. Subtask C then seeks to utilize both the aero-acoustic data bases developed in Subtask A and the analytical methods developed in Subtask B to define improved subsonic mixed-flow exhaust systems. The mixed flow systems defined in Subtask C will be experimentally demonstrated for improved noise reduction in a scale model aero-acoustic test conducted similarly to the test performed in Subtask A. The overall object of this Task Order is to develop and demonstrate the technology to define a -3EPNdB exhaust system relative to 1992 exhaust system technology.

  8. Drug Transporters and Na+/H+ Exchange Regulatory Factor PSD-95/Drosophila Discs Large/ZO-1 Proteins

    PubMed Central

    Walsh, Dustin R.; Nolin, Thomas D.

    2015-01-01

    Drug transporters govern the absorption, distribution, and elimination of pharmacologically active compounds. Members of the solute carrier and ATP binding-cassette drug transporter family mediate cellular drug uptake and efflux processes, thereby coordinating the vectorial movement of drugs across epithelial barriers. To exert their physiologic and pharmacological function in polarized epithelia, drug transporters must be targeted and stabilized to appropriate regions of the cell membrane (i.e., apical versus basolateral). Despite the critical importance of drug transporter membrane targeting, the mechanisms that underlie these processes are largely unknown. Several clinically significant drug transporters possess a recognition sequence that binds to PSD-95/Drosophila discs large/ZO-1 (PDZ) proteins. PDZ proteins, such as the Na+/H+ exchanger regulatory factor (NHERF) family, act to stabilize and organize membrane targeting of multiple transmembrane proteins, including many clinically relevant drug transporters. These PDZ proteins are normally abundant at apical membranes, where they tether membrane-delimited transporters. NHERF expression is particularly high at the apical membrane in polarized tissue such as intestinal, hepatic, and renal epithelia, tissues important to drug disposition. Several recent studies have highlighted NHERF proteins as determinants of drug transporter function secondary to their role in controlling membrane abundance and localization. Mounting evidence strongly suggests that NHERF proteins may have clinically significant roles in pharmacokinetics and pharmacodynamics of several pharmacologically active compounds and may affect drug action in cancer and chronic kidney disease. For these reasons, NHERF proteins represent a novel class of post-translational mediators of drug transport and novel targets for new drug development. PMID:26092975

  9. Angular momentum transport and large eddy simulations in magnetorotational turbulence: the small Pm limit

    NASA Astrophysics Data System (ADS)

    Meheut, Heloise; Fromang, Sébastien; Lesur, Geoffroy; Joos, Marc; Longaretti, Pierre-Yves

    2015-07-01

    Context. Angular momentum transport in accretion discs is often believed to be due to magnetohydrodynamic turbulence mediated by the magnetorotational instability (MRI). Despite an abundant literature on the MRI, the parameters governing the saturation amplitude of the turbulence are poorly understood and the existence of an asymptotic behaviour in the Ohmic diffusion regime has not been clearly established. Aims: We investigate the properties of the turbulent state in the small magnetic Prandtl number limit. Since this is extremely computationally expensive, we also study the relevance and range of applicability of the most common subgrid scale models for this problem. Methods: Unstratified shearing box simulations are performed both in the compressible and incompressible limits, with a resolution up to 800 cells per disc scale height. This is the highest resolution ever attained for a simulation of MRI turbulence. Different magnetic field geometry and a wide range of dimensionless dissipative coefficients are considered. We also systematically investigate the relevance of using large eddy simulations (LES) in place of direct numerical simulations. Results: In the presence of a mean magnetic field threading the domain, angular momentum transport converges to a finite value in the small Pm limit. When the mean vertical field amplitude is such that β (the ratio between the thermal and magnetic pressure) equals 103, we find α ~ 3.2 × 10-2 when Pm approaches zero. In the case of a mean toroidal field for which β = 100, we find α ~ 1.8 × 10-2 in the same limit. Implicit LES and the Chollet-Lesieur closure model both reproduce these results for the α parameter and the power spectra. A reduction in computational cost by a factor of at least 16 (and up to 256) is achieved when using such methods. Conclusions: MRI turbulence operates efficiently in the small Pm limit provided there is a mean magnetic field. Implicit LES offers a practical and efficient means of

  10. Non-isothermal infiltration and tracer transport experiments on large soil columns

    NASA Astrophysics Data System (ADS)

    Sobotkova, Martina; Snehota, Michal; Cejkova, Eva; Tesar, Miroslav

    2016-04-01

    Isothermal and non-isothermal infiltration experiments were carried out in the laboratory on large undisturbed soil columns (19 cm in diameter, 25 cm high) taken at the experimental catchments Roklan (Sumava Mountains, Czech Republic) and Uhlirska (Jizera Mountains, Czech republic). The aim of the study was twofold. The first goal was to obtain water flow and heat transport data for indirect parameter estimation of thermal and hydraulic properties of soils from two sites by inverse modelling. The second aim was to investigate the extent of impact of the temperature on saturated hydraulic conductivity (Ksat) and dispersity of solute transport. The temperature of infiltrating water in isothermal experiment (20 °C) was equal to the initial temperature of the sample. For non-isothermal experiment water temperature was 5°C, while the initial temperature of the sample was 20°C as in previous case. The experiment was started by flooding the sample surface. Then water level was maintained at constant level throughout the infiltration run using the optical sensor and peristaltic pump. Concentration pulse of deuterium was applied at the top of the soil sample, during the steady state flow. Initial pressure head in the sample was close to field capacity. Two tensiometers and two temperature sensors were inserted in the soil sample in two depths (9 and 15 cm below the top of the sample). Two additional temperature sensors monitored the temperature entering and leaving the samples. Water drained freely through the perforated plate at the bottom of sample by gravity. Inflow and outflow water flux densities, water pressure heads and soil temperatures were monitored continuously during experiments. Effluent was sampled in regular time intervals and samples were analysed for deuterium concentrations by laser spectroscopy to develop breakthrough curves. The outcome of experiments are the series of measured water fluxes, pressure heads and temperatures ready for inverse modelling

  11. Large Amino Acid Transporter 1 Selective Liposomes of l-DOPA Functionalized Amphiphile for Combating Glioblastoma.

    PubMed

    Bhunia, Sukanya; Vangala, Venugopal; Bhattacharya, Dwaipayan; Ravuri, Halley Gora; Kuncha, Madhusudana; Chakravarty, Sumana; Sistla, Ramakrishna; Chaudhuri, Arabinda

    2017-10-10

    Despite significant progress in neurosurgery and radiation therapy during the past decade, overall survivability (OS) of glioblastoma patients continues to be less than 2 years. The scope of systemic chemotherapy is greatly limited by poor drug transport across the blood brain barrier (BBB) and, thereby, suboptimal drug accumulation in glioma tissue. To this end, use of large amino acid transporter-1 (LAT1) overexpressed both on brain capillary endothelial cells (BCECs) and glioma cells has begun. Prior reports on the use of LAT1 mediated delivery of model drugs showed their brain accumulations. However, in depth in vivo glioblastoma regression studies aimed at examining the therapeutic potential of LAT1 mediated delivery of potent chemotherapeutics to brain tumor tissues have not yet been undertaken. Herein, we report on the development of a nanometric (100-135 nm) promising LAT1 selective liposomal drug carrier prepared from a novel l-3,4-dihydroxyphenylalanine (l-DOPA) functionalized amphiphile (Amphi-DOPA). In vitro studies using Rh-PE labeled liposomes of Amphi-DOPA both in untreated glioma (GL261) cells and in GL261cells preincubated with LAT1 antibody revealed LAT1 mediated cellular uptake. Intravenously administered NIR-dye labeled liposomes of Amphi-DOPA in glioblastoma-bearing mice showed preferential accumulation of the dye in brain tissue. Notably iv administration of WP1066-loaded liposomes of Amphi-DOPA enhanced the overall survivability of C57BL/6J mice bearing orthotopically established mouse glioblastoma by ∼60% compared to that for the untreated mouse group. Furthermore, we show that the OS of established glioblastoma-bearing mice can be significantly enhanced (by >300% compared to that for the untreated mouse group) when the presently described LAT1 mediated targeted chemotherapy with WP1066-loaded liposomes of Amphi-DOPA is combined with in vivo DC-targeted DNA vaccination using a survivin (a glioblastoma antigen) encoded DNA vaccine. The

  12. Experimental evaluation of compliant surfaces at low speeds. [aerodynamic drag of subsonic wind tunnel model

    NASA Technical Reports Server (NTRS)

    Mcalister, K. W.; Wynn, T. M.

    1974-01-01

    An experimental study was devised to determine the profile drag on a subsonic wind tunnel model partially covered with various compliant surface materials. The model consisted of a large section of constant thickness bounded fore and aft by symmetric airfoil fairings. A flat rigid plate, the control surface, could be exchanged for four contiguous complaint panels. The flexible media generally consisted of thin polyvinylchloride membranes stretched to various tensions over trapped fluid cavities of air, water, or polyethelene oxide solution, or over dry or flooded open-celled polyurethane foams. On the basis of very accurate direct-force cell measurements, all configurations were found to yield profile drags equal to or slightly higher than that obtained for the conventional rigid surface case. The results indicate that the potential for practical drag-reducing applications will be limited to either high-density or high-speed flows where more sensible pressure perturbations occur.

  13. On an acoustic field generated by subsonic jet at low Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Yamamoto, K.; Arndt, R. E. A.

    1978-01-01

    An acoustic field generated by subsonic jets at low Reynolds numbers was investigated. This work is motivated by the need to increase the fundamental understanding of the jet noise generation mechanism which is essential to the development of further advanced techniques of noise suppression. The scope of this study consists of two major investigation. One is a study of large scale coherent structure in the jet turbulence, and the other is a study of the Reynolds number dependence of jet noise. With this in mind, extensive flow and acoustic measurements in low Reynolds number turbulent jets (8,930 less than or equal to M less than or equal to 220,000) were undertaken using miniature nozzles of the same configuration but different diameters at various exist Mach numbers (0.2 less than or equal to M less than or equal to 0.9).

  14. Flow field and near and far sound field of a subsonic jet

    NASA Technical Reports Server (NTRS)

    Zaman, K. B. M. Q.

    1986-01-01

    Flow and sound field data are presented for a 2.54 cm diameter air jet at a Mach number of 0.50 and a Reynolds number of 300,000. Distributions of mean velocity, turbulence intensities, Reynolds stress, spectral components of turbulence as well as of the near field pressure, together with essential characteristics of the far field sound are reported. This detailed set of data for one particular flow, erstwhile unavailable in the literature, is expected to help promoote and calibrate subsonic jet noise theories. 'Source locations' in terms of the turbulence maxima, coupling between the entrainment dynamics and the near pressure field, the sound radiation paths, and the balance in mass, momentum and sound energy fluxes are discussed. The results suggest that the large scale coherent structures of the jet govern the 'source locations' by controlling the turbulence and also strongly influence the near field pressure fluctuations.

  15. Onset of cavity deformation upon subsonic motion of a projectile in a fluid complex plasma.

    PubMed

    Zhukhovitskii, D I; Ivlev, A V; Fortov, V E; Morfill, G E

    2013-06-01

    We study the deformation of a cavity around a large projectile moving with subsonic velocity in the cloud of small dust particles. To solve this problem, we employ the Navier-Stokes equation for a compressible fluid with due regard for friction between dust particles and atoms of neutral gas. The solution shows that due to friction, the pressure of a dust cloud at the surface of a cavity around the projectile can become negative, which entails the emergence of a considerable asymmetry of the cavity, i.e., the cavity deformation. Corresponding threshold velocity is calculated, which is found to decrease with increasing cavity size. Measurement of such velocity makes it possible to estimate the static pressure inside the dust cloud.

  16. A computer program for wing subsonic aerodynamic performance estimates including attainable thrust and vortex lift effects

    NASA Technical Reports Server (NTRS)

    Carlson, H. W.; Walkley, K. B.

    1982-01-01

    Numerical methods incorporated into a computer program to provide estimates of the subsonic aerodynamic performance of twisted and cambered wings of arbitrary planform with attainable thrust and vortex lift considerations are described. The computational system is based on a linearized theory lifting surface solution which provides a spanwise distribution of theoretical leading edge thrust in addition to the surface distribution of perturbation velocities. The approach used relies on a solution by iteration. The method also features a superposition of independent solutions for a cambered and twisted wing and a flat wing of the same planform to provide, at little additional expense, results for a large number of angles of attack or lift coefficients. A previously developed method is employed to assess the portion of the theoretical thrust actually attainable and the portion that is felt as a vortex normal force.

  17. The Role of HO(x) in Super- and Subsonic Aircraft Exhaust Plumes

    NASA Technical Reports Server (NTRS)

    Hanisco, T. F.; Wennberg, P. O.; Cohen, R. C.; Anderson, J. G.; Fahey, D. W.; Keim, E. R.; Gao, R. S.; Wamsley, R. C.; Donnelly, S. G.; DelNegro, L. A.; hide

    1997-01-01

    The generation of sulfuric acid aerosols in aircraft exhaust has emerged as a critical issue in determining the impact of supersonic aircraft on stratospheric ozone. It has long been held that the first step in the mechanism of aerosol formation is the oxidation of SO2 emitted from the engine by OH in the exhaust plume. We report in situ measurements of OH and HO2 in the exhaust plumes of a supersonic (Air France Concorde) and a subsonic (NASA ER-2) aircraft in the lower stratosphere. These measurements imply that reactions with OH are responsible for oxidizing only a small fraction of SO2 (2%), and thus cannot explain the large number of particles observed in the exhaust wake of the Concorde.

  18. The Role of HO(x) in Super- and Subsonic Aircraft Exhaust Plumes

    NASA Technical Reports Server (NTRS)

    Hanisco, T. F.; Wennberg, P. O.; Cohen, R. C.; Anderson, J. G.; Fahey, D. W.; Keim, E. R.; Gao, R. S.; Wamsley, R. C.; Donnelly, S. G.; DelNegro, L. A.; hide

    1997-01-01

    The generation of sulfuric acid aerosols in aircraft exhaust has emerged as a critical issue in determining the impact of supersonic aircraft on stratospheric ozone. It has long been held that the first step in the mechanism of aerosol formation is the oxidation of SO2, emitted from the engine by OH in the exhaust plume. We report in situ measurements of OH and HO, in the exhaust plumes of a supersonic (Air France Concorde) and a subsonic (NASA ER-2) aircraft in the lower stratosphere. These measurements imply that reactions with OH are responsible for oxidizing only a small fraction of SO2 (2%), and thus cannot explain the large number of particles observed in the exhaust wake of the Concorde.

  19. Flow field and near and far sound field of a subsonic jet

    NASA Technical Reports Server (NTRS)

    Zaman, K. B. M. Q.

    1986-01-01

    Flow and sound field data are presented for a 2.54 cm diameter air jet at a Mach number of 0.50 and a Reynolds number of 300,000. Distributions of mean velocity, turbulence intensities, Reynolds stress, spectral components of turbulence as well as of the near field pressure, together with essential characteristics of the far field sound are reported. This detailed set of data for one particular flow, erstwhile unavailable in the literature, is expected to help promoote and calibrate subsonic jet noise theories. 'Source locations' in terms of the turbulence maxima, coupling between the entrainment dynamics and the near pressure field, the sound radiation paths, and the balance in mass, momentum and sound energy fluxes are discussed. The results suggest that the large scale coherent structures of the jet govern the 'source locations' by controlling the turbulence and also strongly influence the near field pressure fluctuations.

  20. Influence of configuration details on the subsonic characteristics of a space shuttle orbiter design

    NASA Technical Reports Server (NTRS)

    Decker, J. P.; Phillips, W. P.

    1974-01-01

    An investigation was conducted in the Langley low-turbulence pressure tunnel of a model of a space shuttle orbiter design in order to determine the influence of minor configuration geometric details on the aerodynamic characteristics at subsonic speeds. A plane wing was tested with a small planform fillet; a twisted wing was tested with both a small and a large planform fillet. Tailored attitude-control propulsion-system wing-tip and body pods, trisegmented elevons, and canopy effects were also investigated. The tests were conducted at angles of attack from -3 deg to 24 deg for sideslip angles of 0 deg and 6 deg and at a Mach number of 0.25.

  1. On the theory of oscillating airfoils of finite span in subsonic compressible flow

    NASA Technical Reports Server (NTRS)

    Reissner, Eric

    1950-01-01

    The problem of oscillating lifting surface of finite span in subsonic compressible flow is reduced to an integral equation. The kernel of the integral equation is approximated by a simpler expression, on the basis of the assumption of sufficiently large aspect ratio. With this approximation the double integral occurring in the formulation of the problem is reduced to two single integrals, one of which is taken over the chord and the other over the span of the lifting surface. On the basis of this reduction the three-dimensional problem appears separated into two two-dimensional problems, one of them being effectively the problem of two-dimensional flow and the other being the problem of spanwise circulation distribution. Earlier results concerning the oscillating lifting surface of finite span in incompressible flow are contained in the present more general results.

  2. Hydrogen transport diagnostics by atomic and molecular emission line profiles simultaneously measured for large helical device

    SciTech Connect

    Fujii, K.; Shikama, T.; Hasuo, M.; Goto, M.; Morita, S.

    2013-01-15

    We observe the Balmer-{alpha}, -{beta}, and -{gamma} lines of hydrogen atoms and Q branches of the Fulcher-{alpha} band of hydrogen molecules simultaneously with their polarization resolved for large helical device. From the fit including the line splits and the polarization dependences by the Zeeman effect, the emission locations, intensities, and the temperatures of the atoms and molecules are determined. The emission locations of the hydrogen atoms are determined outside but close to the last closed flux surface (LCFS). The results are consistent with a previous work (Phys. Plasmas 12, 042501 (2005)). On the other hand, the emission locations of the molecules are determined to be in the divertor legs, which is farer from those of the atoms. The kinetic energy of the atoms is 1 {approx} 20 eV, while the rotational temperature of molecules is {approx}0.04 eV. Additionally, substantial wings, which originate from high velocity atoms and are not reproduced by the conventional spectral analysis, are observed in the Balmer line profiles. We develop a one-dimensional model to simulate the transport of the atoms and molecules. The model reproduces the differences of the emission locations of the atoms and molecules when their initial temperatures are assumed to be 3 eV and 0.04 eV, respectively. From the model, the wings of the Balmer-{alpha} line is attributed to the high velocity atoms exist deep inside the LCFS, which are generated by the charge exchange collisions with hot protons there.

  3. Parametric Study of the Flutter Stability of a Semi-Rigid 3-D Wing-With-Engine Nacelle Model in Subsonic Flow

    NASA Astrophysics Data System (ADS)

    Försching, H.; Knaack, J. M.

    1993-08-01

    A parametric investigation is performed of the aeroelastic flutter stability behaviour of a semi-rigid 3-D wing-with-engine nacelle model in subsonic flow. The system under investigation is a wind tunnel model that was flutter tested some years ago. It consists of a swept-back half wing with a pylon-mounted engine nacelle, representative of modern large transport aircraft, and is elastically restrained at its wing root, so that it may execute decoupled (rigid body) rolling and pitching oscillations about two orthogonal axes. For this binary aeroelastic system, first the equations of motion and then the aeroelastic stability equations are set up in terms of generalized coordinates. In addition to the basic wind tunnel model configuration, two artificial configurations with other positions of the rotation axes and corresponding mode shapes are investigated. For the computation of the motion-induced generalized airloads, a panel technique is used for both the wing and the engine nacelle that is replaced by an annular wing. Numerical results are presented for several systematic parameter variations and Mach numbers, where special emphasis is placed on the effects of the motion-induced unsteady airloads acting on the engine nacelle, the position of the rotation axes, and the frequency ratio of the two modes in roll and pitch. Moreover, a comparison is made with some wind tunnel test results.

  4. TRANSPORT

    EPA Science Inventory

    Presentation outline: transport principles, effective solubility; gasoline composition; and field examples (plume diving).
    Presentation conclusions: MTBE transport follows from - phyiscal and chemical properties and hydrology. Field examples show: MTBE plumes > benzene plu...

  5. Stochastic dynamics from the fractional Fokker-Planck-Kolmogorov equation: large-scale behavior of the turbulent transport coefficient.

    PubMed

    Milovanov, A V

    2001-04-01

    The formulation of the fractional Fokker-Planck-Kolmogorov (FPK) equation [Physica D 76, 110 (1994)] has led to important advances in the description of the stochastic dynamics of Hamiltonian systems. Here, the long-time behavior of the basic transport processes obeying the fractional FPK equation is analyzed. A derivation of the large-scale turbulent transport coefficient for a Hamiltonian system with 11 / 2 degrees of freedom is proposed in connection with the fractal structure of the particle chaotic trajectories. The principal transport regimes (i.e., a diffusion-type process, ballistic motion, subdiffusion in the limit of the frozen Hamiltonian, and behavior associated with self-organized criticality) are obtained as partial cases of the generalized transport law. A comparison with recent numerical and experimental studies is given.

  6. Sediment budgets, transport, and depositional trends in a large tidal delta

    USGS Publications Warehouse

    Morgan, Tara; Wright, Scott A.

    2016-01-01

    The Sacramento-San Joaquin Delta is the largest delta on the west coast of the United States. It is formed where the confluence of California’s two largest rivers (the Sacramento and San Joaquin) meet the ocean tides and has a significant physical gradient from fluvial to tidal. It is a semidiurnal system (two high and two low tides per day). Today, the Delta is one of the most manipulated in the United States. Once composed of many shallow, meandering and braided dendritic channels and dead-end sloughs and wetlands, it is now a network of leveed canals moving clear water around subsided islands. It historically has supported a biologically diverse tidal wetland complex, of which only 3% remains today (Whipple et al., 2012). It has also witnessed a collapse in the native fish populations. The Delta provides critical habitat for native species, however the hydrology and water quality are complicated by manipulations and diversions to satisfy multiple statewide objectives. Today water managers face co-equal goals of water supply to Californians and maintenance of ecosystem health and function. The Delta is a hub for both a multi-hundred-million dollar agricultural industry and a massive north-to-south water delivery system, supplying the primary source of freshwater to Central Valley farmers and drinking water for two-thirds of California’s population. Large pump facilities support the water demand and draw water from the Delta, further altering circulation patterns and redirecting the net flow toward the export facilities (Monsen et al., 2007). Fluvial sedimentation, along with organic accumulation, creates and sustains the Delta landscape. Hydraulic mining for gold in the watershed during the late 1800s delivered an especially large sediment pulse to the Delta. More recently, from 1955 to the present, a significant sediment decline has been observed that is thought to have been caused mostly by the construction of water storage reservoirs that trap the upstream

  7. Sound radiation from a subsonic rotor subjected to turbulence

    NASA Technical Reports Server (NTRS)

    Sevik, M.

    1974-01-01

    The broadband sound radiated by a subsonic rotor subjected to turbulence in the approach stream has been analyzed. The power spectral density of the sound intensity has been found to depend on a characteristic time scale-namely, the integral scale of the turbulence divided by the axial flow velocity-as well as several length-scale ratios. These consist of the ratio of the integral scale to the acoustic wavelength, rotor radius, and blade chord. Due to the simplified model chosen, only a limited number of cascade parameters appear. Limited comparisons with experimental data indicate good agreement with predicted values.

  8. Simulation of Atmospheric-Entry Capsules in the Subsonic Regime

    NASA Technical Reports Server (NTRS)

    Murman, Scott M.; Childs, Robert E.; Garcia, Joseph A.

    2015-01-01

    The accuracy of Computational Fluid Dynamics predictions of subsonic capsule aerodynamics is examined by comparison against recent NASA wind-tunnel data at high-Reynolds-number flight conditions. Several aspects of numerical and physical modeling are considered, including inviscid numerical scheme, mesh adaptation, rough-wall modeling, rotation and curvature corrections for eddy-viscosity models, and Detached-Eddy Simulations of the unsteady wake. All of these are considered in isolation against relevant data where possible. The results indicate that an improved predictive capability is developed by considering physics-based approaches and validating the results against flight-relevant experimental data.

  9. Computation of subsonic base flow on a vector processor

    NASA Technical Reports Server (NTRS)

    Rudy, D. H.

    1987-01-01

    Two-dimensional subsonic laminar compressible base flow has been studied using numerical solutions of the time-dependent Navier-Stokes equations. These solutions were obtained using an explicit finite-difference scheme which is highly efficient on a vector processor. The organization of the code for a CDC CYBER-205 computer is described. Solutions were obtained for Mach 0.4 and 0.6 flows past a slender blunt-based model at moderately high Reynolds numbers. The flow in the wake is unsteady with periodic shedding of vortices from the trailing edge. The computed shedding frequency was found to increase with increasing Reynolds number.

  10. NASA Subsonic Rotary Wing Project - Structures and Materials Discipline

    NASA Technical Reports Server (NTRS)

    Halbig, Michael C.; Johnson, Susan M.

    2008-01-01

    The Structures & Materials Discipline within the NASA Subsonic Rotary Wing Project is focused on developing rotorcraft technologies. The technologies being developed are within the task areas of: 5.1.1 Life Prediction Methods for Engine Structures & Components 5.1.2 Erosion Resistant Coatings for Improved Turbine Blade Life 5.2.1 Crashworthiness 5.2.2 Methods for Prediction of Fatigue Damage & Self Healing 5.3.1 Propulsion High Temperature Materials 5.3.2 Lightweight Structures and Noise Integration The presentation will discuss rotorcraft specific technical challenges and needs as well as details of the work being conducted in the six task areas.

  11. Finite element analysis of inviscid subsonic boattail flow

    NASA Technical Reports Server (NTRS)

    Chima, R. V.; Gerhart, P. M.

    1981-01-01

    A finite element code for analysis of inviscid subsonic flows over arbitrary nonlifting planar or axisymmetric bodies is described. The code solves a novel primitive variable formulation of the coupled irrotationality and compressible continuity equations. Results for flow over a cylinder, a sphere, and a NACA 0012 airfoil verify the code. Computed subcritical flows over an axisymmetric boattailed afterbody compare well with finite difference results and experimental data. Interative coupling with an integral turbulent boundary layer code shows strong viscous effects on the inviscid flow. Improvements in code efficiency and extensions to transonic flows are discussed.

  12. Minimizing life cycle cost for subsonic commercial aircraft

    NASA Technical Reports Server (NTRS)

    Johnson, Vicki S.

    1990-01-01

    A methodology is presented which facilitates the identification of that aircraft design concept which will incur the lowest life-cycle costs (LCCs) while meeting mission requirements. The methodology consists of an LCC module whose constituent elements calculate the costs associated with R&D, testing, evaluation, and production, as well as direct and indirect operating costs, in conjunction with the 'Flight Optimization System' conceptual design/analysis code. Provision is made in the methodology for sensitivities to advanced technologies for the subsonic commercial aircraft in question, which are optimized with respect to minimum gross weight, fuel consumption, acquisition cost, and direct operating cost.

  13. High speed visualizations applied to subsonic and transonic base flow

    NASA Astrophysics Data System (ADS)

    Rodriguez, O.; Ducruet, C.; Desse, J. M.

    The present experimental study of two-dimensional base flows at subsonic and transonic speeds gives attention to their unsteady properties through the synchronization of high speed visualizations with pressure measurements. The optical test apparatus employed may function as either a shadowgraph or a schlieren system. The time history of the observed phenomenon is restored, and it is found that it is possible to determine the effects of the vortex street on the body in question for different values of the parameters that are involved in the problem investigated.

  14. Subsonic/transonic stall flutter investigation of a rotating rig

    NASA Technical Reports Server (NTRS)

    Jutras, R. R.; Fost, R. B.; Chi, R. M.; Beacher, B. F.

    1981-01-01

    Stall flutter is investigated by obtaining detailed quantitative steady and aerodynamic and aeromechanical measurements in a typical fan rotor. The experimental investigation is made with a 31.3 percent scale model of the Quiet Engine Program Fan C rotor system. Both subsonic/transonic (torsional mode) flutter and supersonic (flexural) flutter are investigated. Extensive steady and unsteady data on the blade deformations and aerodynamic properties surrounding the rotor are acquired while operating in both the steady and flutter modes. Analysis of this data shows that while there may be more than one traveling wave present during flutter, they are all forward traveling waves.

  15. Solution of the unsteady subsonic thin airfoil problem

    NASA Technical Reports Server (NTRS)

    Williams, M. H.

    1982-01-01

    The problem of a thin airfoil subject to simple harmonic disturbances in a uniform subsonic free stream is solved by extension of a technique developed earlier for a stationary strip vibrating in a uniform fluid. Explicit expressions are given for the lift and moment, acoustic directivity pattern, and total acoustic power for arbitrary upwash and, in particular, for the 'elementary disturbances': plunge, pitch and a stationary transverse gust. Numerical results for a simple skewed gust are presented and compared to the high-frequency asymptotic theory of Martinez and Widnall.

  16. Acoustic measurement study 40 by 80 foot subsonic wind tunnel

    NASA Technical Reports Server (NTRS)

    1974-01-01

    An acoustical study conducted during the period from September 1, 1973 to April 30, 1974 measured sound pressure levels and vibration amplitudes inside and outside of the subsonic tunnel and on the tunnel structure. A discussion of the technical aspects of the study, the field measurement and data reduction procedures, and results are presentd, and conclusions resulting from the study which bear upon near field and far field tunnel noise, upon the tunnel as an acoustical enclosure, and upon the sources of noise within the tunnel drive system are given.

  17. Drive of parallel flows by turbulence and large-scale E × B transverse transport in divertor geometry

    NASA Astrophysics Data System (ADS)

    Galassi, D.; Tamain, P.; Bufferand, H.; Ciraolo, G.; Ghendrih, Ph.; Baudoin, C.; Colin, C.; Fedorczak, N.; Nace, N.; Serre, E.

    2017-03-01

    The poloidal asymmetries of parallel flows in edge plasmas are investigated by the 3D fluid turbulence code TOKAM3X. A diverted COMPASS-like magnetic equilibrium is used for the simulations. The measurements and simulations of parallel Mach numbers are compared, and exhibit good qualitative agreement. Small-scale turbulent transport is observed to dominate near the low field side midplane, even though it co-exists with significant large-scale cross-field fluxes. Despite the turbulent nature of the plasma in the divertor region, simulations show the low effectiveness of turbulence for the cross-field transport towards the private flux region. Nevertheless, a complex pattern of fluxes associated with the average field components are found to cross the separatrix in the divertor region. Large-scale and small-scale turbulent E× B transport, along with the \

  18. Sediment Transport and bedform dynamics during a major, typhoon-driven, flood on a large tropical river

    NASA Astrophysics Data System (ADS)

    Unsworth, Christopher; Parsons, Daniel; Keevil, Claire; Darby, Stephen; Hackney, Chris; Leyland, Julian; Best, Jim; Nicholas, Andy; Aalto, Rolf

    2015-04-01

    Fluvial sediment transport in tropical-monsoonal rivers are characterised by some of the highest sediment yields on Earth, yet the unsteady dynamics and partitioning of sediment transport as bedload and suspended load during floods has received little attention. Herein, results from multiple field surveys of a section of the Mekong River (in Cambodia) reveal the variability in sediment transport during a large flood in 2013. High-resolution MultiBeam EchoSounder (MBES) surveys produced river bed bathymetric maps to record the movement of sedimentary bedforms though time. Suspended sediment transport rates and flow velocities were concurrently measured using an acoustic Doppler current profiler (ADCP). These surveys found major changes in the type and size of bedforms present through time. Barchan dunes that were present before, during and after the peak flood are denudated massively at the peak of the flood by large numbers of secondary superimposed bedforms. However, during the falling limb of the flood these secondary dunes merged with the Barchans to produce the largest bedforms measured in the surveys. The difference in bedload sediment transport rates between the peak and waning leg of a major flood event was also quantified. Data from the ADCP reveals a match between local flow velocities, bed shear stress and Rouse number that can be related to the changes in suspended sediment concentration across the river channel. This impacted the shape of bedforms though alteration of the dominant mode of sediment transport, which varied considerably across the channel. These factors contributed to a spatial disparity in local storing and erosion of sediment within the river channel. This paper will highlight the above findings and discuss the implications for modelling the response of large river morphodynamics to large flood events.

  19. Analytical study of suction boundary layer control for subsonic V/STOL inlets

    NASA Technical Reports Server (NTRS)

    Boles, M. A.; Ramesh, K.; Hwang, D. P.

    1984-01-01

    Analytical procedures used to evaluate the application of suction boundary-layer control (BLC) to subsonic V/STOL inlets are presented. These procedures have been used to analytically predict the optimum (minimum suction power required) location and extent for a suction slot of two different surface resistances within a subsonic V/STOL inlet. Results of this analytical study are presented.

  20. Transportation of Large Wind Components: A Review of Existing Geospatial Data

    SciTech Connect

    Mooney, Meghan; Maclaurin, Galen

    2016-09-01

    This report features the geospatial data component of a larger project evaluating logistical and infrastructure requirements for transporting oversized and overweight (OSOW) wind components. The goal of the larger project was to assess the status and opportunities for improving the infrastructure and regulatory practices necessary to transport wind turbine towers, blades, and nacelles from current and potential manufacturing facilities to end-use markets. The purpose of this report is to summarize existing geospatial data on wind component transportation infrastructure and to provide a data gap analysis, identifying areas for further analysis and data collection.