WorldWideScience

Sample records for supersonic flowfield calculations

  1. Flowfield Behavior of Supersonic Impinging Jets

    Science.gov (United States)

    Iyer, K. G.; Alvi, F. S.

    1998-11-01

    A detailed study is being conducted which examines the behavior of normally impinging, supersonic jets, issuing from axisymmetric a Mach 1.5 C-D and a sonic nozzle. Our goal is to understand the physics of this flowfield (commonly observed in STOVL aircraft) and its influence on the acoustic and aerodynamic loading on the ground plane and the airframe. The airframe is simulated by a circular disc ('lift' plate) with an annular hole from which the jet is issued. Tests are carried out for a wide range of pressure ratios and the ground plane distance is varied from 1.5 to 60 nozzle diameters. Flowfield measurements include Particle Image Velocimetry (PIV) and schlieren/shadowgraph visualization. Surface measurements on the ground and lift plates include mean and unsteady surface pressure distributions and the surface streamline visualization. Near-field acoustic measurements using a microphone are also obtained. For certain cases, the PIV measurements -- first of their kind, to our knowledge -- clearly show the presence of large-scale coherent turbulent structures which, upon jet impingement, propagate into the resulting wall jet. These structures are believed to generate very high unsteady pressure loads on the ground plane thus leading to ground erosion. They are also suspected to be the source of acoustic waves which lead to a feedback loop causing violent oscillations of the primary jet and can result in increased acoustic loading and subsequent damage to the aircraft. As a result of this detailed study over a wide parametric space, we hope to gain a much better understanding of the physical mechanisms governing this complex flow.

  2. Method and system for control of upstream flowfields of vehicle in supersonic or hypersonic atmospheric flight

    Science.gov (United States)

    Daso, Endwell O. (Inventor); Pritchett, II, Victor E. (Inventor); Wang, Ten-See (Inventor); Farr, Rebecca Ann (Inventor)

    2012-01-01

    The upstream flowfield of a vehicle traveling in supersonic or hypersonic atmospheric flight is actively controlled using attribute(s) experienced by the vehicle. Sensed attribute(s) include pressure along the vehicle's outer mold line, temperature along the vehicle's outer mold line, heat flux along the vehicle's outer mold line, and/or local acceleration response of the vehicle. A non-heated, non-plasma-producing gas is injected into an upstream flowfield of the vehicle from at least one surface location along the vehicle's outer mold line. The pressure of the gas so-injected is adjusted based on the attribute(s) so-sensed.

  3. SparkJet characterizations in quiescent and supersonic flowfields

    Science.gov (United States)

    Emerick, T.; Ali, M. Y.; Foster, C.; Alvi, F. S.; Popkin, S.

    2014-12-01

    The aerodynamic community has studied active flow control actuators for some time, and developments have led to a wide variety of devices with various features and operating mechanisms. The design requirements for a practical actuator used for active flow control include reliable operation, requisite frequency and amplitude modulation capabilities, and a reasonable lifespan while maintaining minimal cost and design complexity. An active flow control device called the SparkJet actuator has been developed for high-speed flight control and incorporates no mechanical/moving parts, zero net mass flux capabilities and the ability to tune the operating frequency and momentum throughput. This actuator utilizes electrical power to deliver high-momentum flow with a very fast response time. The SparkJet actuator was characterized on the benchtop using a laser-based microschlieren visualization technique and maximum blast wave and jet front velocities of ~400 and ~310 m/s were, respectively, measured in the flowfield. An increase in jet front velocity from 240 to 310 m/s during subatmospheric (60 kPa) testing reveals that the actuator may have greater control authority at lower ambient pressures, which correspond to high-altitude flight conditions for air vehicles. A SparkJet array was integrated into a flat plate and tested in a Mach 1.5 crossflow. Phase-conditioned shadowgraph results revealed a maximum flow deflection angle of 5° created by the SparkJet 275 µs after the actuator was triggered in single-shot mode. Burst mode operation of frequencies up to 700 Hz revealed similar results during wind tunnel testing. Following these tests, the actuator trigger mechanism was improved and the ability of the actuator to be discharged in burst mode at a frequency of 1 kHz was achieved.

  4. Study on the characteristics of interaction flowfields induced by supersonic jet on a revolution body

    Directory of Open Access Journals (Sweden)

    S.J. Luo

    2017-11-01

    Full Text Available The paper focuses on the triple jets interaction with a hypersonic external flow on a revolution body. The experimental model is a ogive-cylinder body with three supersonic nozzles, which are aligned along the flow direction. The freestream Mach numbers are 5 and 6. The spatial and surface flow characteristics are illustrated by the schlieren photographs and the typical pressure distribution. The results show that there are multi-wave system, separation, reattachment, multi-peak pressure, high-pressure and low-pressure zone boundaries obvious distinction in tri-jets interference flowfield. The present paper also analyzes how do the pressure ratio, the angle of attack, and Mach number effect on tri-jets interaction characteristics.

  5. Navier-Stokes Calculations of Helicopter Fuselage Flowfield and Loads

    DEFF Research Database (Denmark)

    M, Costes; Filippone, Antonino; N, Kroll

    1999-01-01

    This paper describes the theoretically basedactivities conducted during the first year of theBrite/Euram Helifuse Porgramme. These activitiesmainly consisted of the numerical prediction ofhelicopter fuselage flowfields with existing Navier-Stokes solvers on a number of pre-selectedcases, taken out...

  6. An implicit flux-split algorithm to calculate hypersonic flowfields in chemical equilibrium

    Science.gov (United States)

    Palmer, Grant

    1987-01-01

    An implicit, finite-difference, shock-capturing algorithm that calculates inviscid, hypersonic flows in chemical equilibrium is presented. The flux vectors and flux Jacobians are differenced using a first-order, flux-split technique. The equilibrium composition of the gas is determined by minimizing the Gibbs free energy at every node point. The code is validated by comparing results over an axisymmetric hemisphere against previously published results. The algorithm is also applied to more practical configurations. The accuracy, stability, and versatility of the algorithm have been promising.

  7. Practical Calculation of Second-order Supersonic Flow past Nonlifting Bodies of Revolution

    Science.gov (United States)

    Van Dyke, Milton D

    1952-01-01

    Calculation of second-order supersonic flow past bodies of revolution at zero angle of attack is described in detail, and reduced to routine computation. Use of an approximate tangency condition is shown to increase the accuracy for bodies with corners. Tables of basic functions and standard computing forms are presented. The procedure is summarized so that one can apply it without necessarily understanding the details of the theory. A sample calculation is given, and several examples are compared with solutions calculated by the method of characteristics.

  8. Flowfield modeling and diagnostics

    International Nuclear Information System (INIS)

    Gupta, A.K.; Lilley, D.G.

    1985-01-01

    This textbook is devoted solely to flowfield modeling and diagnostics; their practical use, recent and current research, and projected developments and trends. It provides an account of the use of a broad range of techniques in industrial and research practice, both with and without combustion. Application ideas are complemented by details about experimental and modeling techniques

  9. Flowfield computer graphics

    Science.gov (United States)

    Desautel, Richard

    1993-01-01

    The objectives of this research include supporting the Aerothermodynamics Branch's research by developing graphical visualization tools for both the branch's adaptive grid code and flow field ray tracing code. The completed research for the reporting period includes development of a graphical user interface (GUI) and its implementation into the NAS Flowfield Analysis Software Tool kit (FAST), for both the adaptive grid code (SAGE) and the flow field ray tracing code (CISS).

  10. Supersonic flow with shock waves. Monte-Carlo calculations for low density plasma. I

    International Nuclear Information System (INIS)

    Almenara, E.; Hidalgo, M.; Saviron, J. M.

    1980-01-01

    This Report gives preliminary information about a Monte Carlo procedure to simulate supersonic flow past a body of a low density plasma in the transition regime. A computer program has been written for a UNIVAC 1108 machine to account for a plasma composed by neutral molecules and positive and negative ions. Different and rather general body geometries can be analyzed. Special attention is played to tho detached shock waves growth In front of the body. (Author) 30 refs

  11. Thermodynamic equilibrium-air correlations for flowfield applications

    Science.gov (United States)

    Zoby, E. V.; Moss, J. N.

    1981-01-01

    Equilibrium-air thermodynamic correlations have been developed for flowfield calculation procedures. A comparison between the postshock results computed by the correlation equations and detailed chemistry calculations is very good. The thermodynamic correlations are incorporated in an approximate inviscid flowfield code with a convective heating capability for the purpose of defining the thermodynamic environment through the shock layer. Comparisons of heating rates computed by the approximate code and a viscous-shock-layer method are good. In addition to presenting the thermodynamic correlations, the impact of several viscosity models on the convective heat transfer is demonstrated.

  12. MONOTONIC DERIVATIVE CORRECTION FOR CALCULATION OF SUPERSONIC FLOWS WITH SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-07-01

    Full Text Available Subject of Research. Numerical solution methods of gas dynamics problems based on exact and approximate solution of Riemann problem are considered. We have developed an approach to the solution of Euler equations describing flows of inviscid compressible gas based on finite volume method and finite difference schemes of various order of accuracy. Godunov scheme, Kolgan scheme, Roe scheme, Harten scheme and Chakravarthy-Osher scheme are used in calculations (order of accuracy of finite difference schemes varies from 1st to 3rd. Comparison of accuracy and efficiency of various finite difference schemes is demonstrated on the calculation example of inviscid compressible gas flow in Laval nozzle in the case of continuous acceleration of flow in the nozzle and in the case of nozzle shock wave presence. Conclusions about accuracy of various finite difference schemes and time required for calculations are made. Main Results. Comparative analysis of difference schemes for Euler equations integration has been carried out. These schemes are based on accurate and approximate solution for the problem of an arbitrary discontinuity breakdown. Calculation results show that monotonic derivative correction provides numerical solution uniformity in the breakdown neighbourhood. From the one hand, it prevents formation of new points of extremum, providing the monotonicity property, but from the other hand, causes smoothing of existing minimums and maximums and accuracy loss. Practical Relevance. Developed numerical calculation method gives the possibility to perform high accuracy calculations of flows with strong non-stationary shock and detonation waves. At the same time, there are no non-physical solution oscillations on the shock wave front.

  13. Computational Fluid Dynamic Modeling of Rocket Based Combined Cycle Engine Flowfields

    Science.gov (United States)

    Daines, Russell L.; Merkle, Charles L.

    1994-01-01

    Computational Fluid Dynamic techniques are used to study the flowfield of a fixed geometry Rocket Based Combined Cycle engine operating in rocket ejector mode. Heat addition resulting from the combustion of injected fuel causes the subsonic engine flow to choke and go supersonic in the slightly divergent combustor-mixer section. Reacting flow computations are undertaken to predict the characteristics of solutions where the heat addition is determined by the flowfield. Here, adaptive gridding is used to improve resolution in the shear layers. Results show that the sonic speed is reached in the unheated portions of the flow first, while the heated portions become supersonic later. Comparison with results from another code show reasonable agreement. The coupled solutions show that the character of the combustion-based thermal choking phenomenon can be controlled reasonably well such that there is opportunity to optimize the length and expansion ratio of the combustor-mixer.

  14. Numerical analysis of blast flow-field of baffle type muzzle brake

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D.H. [Graduate School, Chungnam National University, Taejon (Korea); Ko, S. [Chungnam National University, Taejon (Korea)

    1998-11-01

    A three-dimensional unsteady, inviscid blast flow-field of a baffle type muzzle brake has been simulated by solving the Euler equation. The blast flow-field includes the effect of the free air blast, precursor blast flow and the propellant blast gas flow. Chimera grid scheme was used to generate 9 multi-block volume grids for the complex geometry. The evolution of the blast flow-field is presented by showing the contours of pressure, density and Mach number for certain time step. The comparison of the calculated and measured peak pressures on the surfaces of the muzzle brake is also presented. (author). 4 refs., 5 figs., 1 tab.

  15. Validation of a Computational Fluid Dynamics (CFD) Code for Supersonic Axisymmetric Base Flow

    Science.gov (United States)

    Tucker, P. Kevin

    1993-01-01

    The ability to accurately and efficiently calculate the flow structure in the base region of bodies of revolution in supersonic flight is a significant step in CFD code validation for applications ranging from base heating for rockets to drag for protectives. The FDNS code is used to compute such a flow and the results are compared to benchmark quality experimental data. Flowfield calculations are presented for a cylindrical afterbody at M = 2.46 and angle of attack a = O. Grid independent solutions are compared to mean velocity profiles in the separated wake area and downstream of the reattachment point. Additionally, quantities such as turbulent kinetic energy and shear layer growth rates are compared to the data. Finally, the computed base pressures are compared to the measured values. An effort is made to elucidate the role of turbulence models in the flowfield predictions. The level of turbulent eddy viscosity, and its origin, are used to contrast the various turbulence models and compare the results to the experimental data.

  16. Properties of Supersonic Impinging Jets

    Science.gov (United States)

    Alvi, F. S.; Iyer, K. G.; Ladd, J.

    1999-11-01

    A detailed study examining the behavior of axisymmetric supersonic jets impinging on a ground plane is described. Our objective is to better understand the aeroacoustics governing this complex flowfield which commonly occurs in the vicinity of STOVL aircraft. Flow issuing through a Mach 1.5 C-D and a converging sonic nozzle is examined over a wide parametric range. For some cases a large diameter circular 'lift' plate, with an annular hole through which the jet is issued, is attached at the nozzle exit to simulate a generic airframe. The impinging jet flowfield was examined using Particle Image Velocimetry (PIV), which provides the velocity field for the entire region and shadowgraph visualization techniques. Near-field acoustic, as well as, mean and unsteady pressure measurements on the ground and lift plate surfaces were also obtained. The velocity field data, together with the surface flow measurements have resulted in a much better understanding of this flow from a fundamental standpoint while also identifying critical regions of interest for practical applications. Some of these findings include the presence of a stagnation bubble with recirculating flow; a very high speed (transonic/supersonic) radial wall jet; presence of large, spatially coherent turbulent structures in the primary jet and wall jet and high unsteady loads on the ground plane and lift plates. The results of a companion CFD investigation and its comparison to the experimental data will also be presented. Very good agreement has been found between the computational and experimental results thus providing confidence in the development of computational tools for the study of such flows.

  17. Supersonic compressor

    Science.gov (United States)

    Roberts, II, William Byron; Lawlor, Shawn P.; Breidenthal, Robert E.

    2016-04-12

    A supersonic compressor including a rotor to deliver a gas at supersonic conditions to a diffuser. The diffuser includes a plurality of aerodynamic ducts that have converging and diverging portions, for deceleration of gas to subsonic conditions and then for expansion of subsonic gas, to change kinetic energy of the gas to static pressure. The aerodynamic ducts include vortex generating structures for controlling boundary layer, and structures for changing the effective contraction ratio to enable starting even when the aerodynamic ducts are designed for high pressure ratios, and structures for boundary layer control. In an embodiment, aerodynamic ducts are provided having an aspect ratio of in excess of two to one, when viewed in cross-section orthogonal to flow direction at an entrance to the aerodynamic duct.

  18. High performance Solid Rocket Motor (SRM) submerged nozzle/combustion cavity flowfield assessment

    Science.gov (United States)

    Freeman, J. A.; Chan, J. S.; Murph, J. E.; Xiques, K. E.

    1987-01-01

    Two and three dimensional internal flowfield solutions for critical points in the Space Shuttle solid rocket booster burn time were developed using the Lockheed Huntsville GIM/PAID Navier-Stokes solvers. These perfect gas, viscous solutions for the high performance motor characterize the flow in the aft segment and nozzle of the booster. Two dimensional axisymmetric solutions were developed at t = 20 and t = 85 sec motor burn times. The t = 85 sec solution indicates that the aft segment forward inhibitor stub produces vortices with are shed and convected downwards. A three dimensional 3.5 deg gimbaled nozzle flowfield solution was developed for the aft segment and nozzle at t = 9 sec motor burn time. This perfect gas, viscous analysis, provided a steady state solution for the core region and the flow through the nozzle, but indicated that unsteady flow exists in the region under the nozzle nose and near the flexible boot and nozzle/case joint. The flow in the nozzle/case joint region is characterized by low magnitude pressure waves which travel in the circumferential direction. From the two and three dimensional flowfield calculations presented it can be concluded that there is no evidence from these results that steady state gas dynamics is the primary mechanism resulting in the nozzle pocketing erosion experienced on SRM nozzles 8A or 17B. The steady state flowfield results indicate pocketing erosion is not directly initiated by a steady state gas dynamics phenomenon.

  19. Low Density Supersonic Decelerators

    Data.gov (United States)

    National Aeronautics and Space Administration — The Low-Density Supersonic Decelerator project will demonstrate the use of inflatable structures and advanced parachutes that operate at supersonic speeds to more...

  20. Supersonic quasi-axisymmetric vortex breakdown

    Science.gov (United States)

    Kandil, Osama A.; Kandil, Hamdy A.; Liu, C. H.

    1991-01-01

    An extensive computational study of supersonic quasi-axisymmetric vortex breakdown in a configured circular duct is presented. The unsteady, compressible, full Navier-Stokes (NS) equations are used. The NS equations are solved for the quasi-axisymmetric flows using an implicit, upwind, flux difference splitting, finite volume scheme. The quasi-axisymmetric solutions are time accurate and are obtained by forcing the components of the flowfield vector to be equal on two axial planes, which are in close proximity of each other. The effect of Reynolds number, for laminar flows, on the evolution and persistence of vortex breakdown, is studied. Finally, the effect of swirl ration at the duct inlet is investigated.

  1. Study on the Impact Characteristics of Coherent Supersonic Jet and Conventional Supersonic Jet in EAF Steelmaking Process

    Science.gov (United States)

    Wei, Guangsheng; Zhu, Rong; Cheng, Ting; Dong, Kai; Yang, Lingzhi; Wu, Xuetao

    2018-02-01

    Supersonic oxygen-supplying technologies, including the coherent supersonic jet and the conventional supersonic jet, are now widely applied in electric arc furnace steelmaking processes to increase the bath stirring, reaction rates, and energy efficiency. However, there has been limited research on the impact characteristics of the two supersonic jets. In the present study, by integrating theoretical modeling and numerical simulations, a hybrid model was developed and modified to calculate the penetration depth and impact zone volume of the coherent and conventional supersonic jets. The computational fluid dynamics results were validated against water model experiments. The results show that the lance height has significant influence on the jet penetration depth and jet impact zone volume. The penetration depth decreases with increasing lance height, whereas the jet impact zone volume initially increases and then decreases with increasing lance height. In addition, the penetration depth and impact zone volume of the coherent supersonic jet are larger than those of the conventional supersonic jet at the same lance height, which illustrates the advantages of the coherent supersonic jet in delivering great amounts of oxygen to liquid melt with a better stirring effect compared to the conventional supersonic jet. A newly defined parameter, the k value, reflects the velocity attenuation and the potential core length of the main supersonic jet. Finally, a hybrid model and its modifications can well predict the penetration depth and impact zone volume of the coherent and conventional supersonic jets.

  2. CFD analyses of coolant channel flowfields

    Science.gov (United States)

    Yagley, Jennifer A.; Feng, Jinzhang; Merkle, Charles L.

    1993-01-01

    The flowfield characteristics in rocket engine coolant channels are analyzed by means of a numerical model. The channels are characterized by large length to diameter ratios, high Reynolds numbers, and asymmetrical heating. At representative flow conditions, the channel length is approximately twice the hydraulic entrance length so that fully developed conditions would be reached for a constant property fluid. For the supercritical hydrogen that is used as the coolant, the strong property variations create significant secondary flows in the cross-plane which have a major influence on the flow and the resulting heat transfer. Comparison of constant and variable property solutions show substantial differences. In addition, the property variations prevent fully developed flow. The density variation accelerates the fluid in the channels increasing the pressure drop without an accompanying increase in heat flux. Analyses of the inlet configuration suggest that side entry from a manifold can affect the development of the velocity profile because of vortices generated as the flow enters the channel. Current work is focused on studying the effects of channel bifurcation on the flow field and the heat transfer characteristics.

  3. Velocity field measurements on high-frequency, supersonic microactuators

    Science.gov (United States)

    Kreth, Phillip A.; Ali, Mohd Y.; Fernandez, Erik J.; Alvi, Farrukh S.

    2016-05-01

    The resonance-enhanced microjet actuator which was developed at the Advanced Aero-Propulsion Laboratory at Florida State University is a fluidic-based device that produces pulsed, supersonic microjets by utilizing a number of microscale, flow-acoustic resonance phenomena. The microactuator used in this study consists of an underexpanded source jet that flows into a cylindrical cavity with a single, 1-mm-diameter exhaust orifice through which an unsteady, supersonic jet issues at a resonant frequency of 7 kHz. The flowfields of a 1-mm underexpanded free jet and the microactuator are studied in detail using high-magnification, phase-locked flow visualizations (microschlieren) and two-component particle image velocimetry. These are the first direct measurements of the velocity fields produced by such actuators. Comparisons are made between the flow visualizations and the velocity field measurements. The results clearly show that the microactuator produces pulsed, supersonic jets with velocities exceeding 400 m/s for roughly 60 % of their cycles. With high unsteady momentum output, this type of microactuator has potential in a range of ow control applications.

  4. Application of Chimera Grid Scheme to Combustor Flowfields at all Speeds

    Science.gov (United States)

    Yungster, Shaye; Chen, Kuo-Huey

    1997-01-01

    A CFD method for solving combustor flowfields at all speeds on complex configurations is presented. The approach is based on the ALLSPD-3D code which uses the compressible formulation of the flow equations including real gas effects, nonequilibrium chemistry and spray combustion. To facilitate the analysis of complex geometries, the chimera grid method is utilized. To the best of our knowledge, this is the first application of the chimera scheme to reacting flows. In order to evaluate the effectiveness of this numerical approach, several benchmark calculations of subsonic flows are presented. These include steady and unsteady flows, and bluff-body stabilized spray and premixed combustion flames.

  5. Large Eddy simulation of turbulent hydrogen-fuelled supersonic combustion in an air cross-flow

    Science.gov (United States)

    Ingenito, A.; Cecere, D.; Giacomazzi, E.

    2013-09-01

    The main aim of this article is to provide a theoretical understanding of the physics of supersonic mixing and combustion. Research in advanced air-breathing propulsion systems able to push vehicles well beyond is of interest around the world. In a scramjet, the air stream flow captured by the inlet is decelerated but still maintains supersonic conditions. As the residence time is very short , the study of an efficient mixing and combustion is a key issue in the ongoing research on compressible flows. Due to experimental difficulties in measuring complex high-speed unsteady flowfields, the most convenient way to understand unsteady features of supersonic mixing and combustion is to use computational fluid dynamics. This work investigates supersonic combustion physics in the Hyshot II combustion chamber within the Large Eddy simulation framework. The resolution of this turbulent compressible reacting flow requires: (1) highly accurate non-dissipative numerical schemes to properly simulate strong gradients near shock waves and turbulent structures away from these discontinuities; (2) proper modelling of the small subgrid scales for supersonic combustion, including effects from compressibility on mixing and combustion; (3) highly detailed kinetic mechanisms (the Warnatz scheme including 9 species and 38 reactions is adopted) accounting for the formation and recombination of radicals to properly predict flame anchoring. Numerical results reveal the complex topology of the flow under investigation. The importance of baroclinic and dilatational effects on mixing and flame anchoring is evidenced. Moreover, their effects on turbulence-scale generation and the scaling law are analysed.

  6. The Trojan. [supersonic transport

    Science.gov (United States)

    1992-01-01

    The Trojan is the culmination of thousands of engineering person-hours by the Cones of Silence Design Team. The goal was to design an economically and technologically viable supersonic transport. The Trojan is the embodiment of the latest engineering tools and technology necessary for such an advanced aircraft. The efficient design of the Trojan allows for supersonic cruise of Mach 2.0 for 5,200 nautical miles, carrying 250 passengers. The per aircraft price is placed at $200 million, making the Trojan a very realistic solution for tomorrows transportation needs. The following is a detailed study of the driving factors that determined the Trojan's super design.

  7. Numerical simulation of steady supersonic flow over spinning bodies of revolution

    Science.gov (United States)

    Sturek, W. B.; Schiff, L. B.

    1982-01-01

    A recently reported parabolized Navier-Stokes code has been employed to compute the supersonic flowfield about a spinning cone and spinning and nonspinning ogive cylinder and boattailed bodies of revolution at moderate incidence. The computations were performed for flow conditions where extensive measurements for wall pressure, boundary-layer velocity profiles, and Magnus force had been obtained. Comparisons between the computational results and experiment indicate excellent agreement for angles of attack up to 6 deg. At angles greater than 6 deg discrepancies are noted which are tentatively attributed to turbulence modeling errors. The comparisons for Magnus effects show that the code accurately predicts the effects of body shape for the selected models.

  8. Nonlinear stability of supersonic jets

    Science.gov (United States)

    Tiwari, S. N. (Principal Investigator); Bhat, T. R. S. (Principal Investigator)

    1996-01-01

    The stability calculations made for a shock-free supersonic jet using the model based on parabolized stability equations are presented. In this analysis the large scale structures, which play a dominant role in the mixing as well as the noise radiated, are modeled as instability waves. This model takes into consideration non-parallel flow effects and also nonlinear interaction of the instability waves. The stability calculations have been performed for different frequencies and mode numbers over a range of jet operating temperatures. Comparisons are made, where appropriate, with the solutions to Rayleigh's equation (linear, inviscid analysis with the assumption of parallel flow). The comparison of the solutions obtained using the two approaches show very good agreement.

  9. Absolute intensities of supersonic beams

    International Nuclear Information System (INIS)

    Beijerinck, H.C.W.; Habets, A.H.M.; Verster, N.F.

    1977-01-01

    In a molecular beam experiment the center-line intensity I(0) (particles s -1 sterad -1 ) and the flow rate dN/dt (particles s -1 ) of a beam source are important features. To compare the performance of different types of beam sources the peaking factor, kappa, is defined as the ratio kappa=π(I(0)/dN/dt). The factor π is added to normalize to kappa=1 for an effusive source. The ideal peaking factor for the supersonic flow from a nozzle follows from continuum theory. Numerical values of kappa are available. Experimental values of kappa for an argon expansion are presented in this paper, confirming these calculations. The actual center-line intensity of a supersonic beam source with a skimmer is reduced in comparison to this ideal intensity if the skimmer shields part of the virtual source from the detector. Experimental data on the virtual source radius are given enabling one to predict this shielding quantitatively. (Auth.)

  10. Supersonic copper clusters

    International Nuclear Information System (INIS)

    Powers, D.E.; Hansen, S.G.; Geusic, M.E.; Michalopoulos, D.L.; Smalley, R.E.

    1983-01-01

    Copper clusters ranging in size from 1 to 29 atoms have been prepared in a supersonic beam by laser vaporization of a rotating copper target rod within the throat of a pulsed supersonic nozzle using helium for the carrier gas. The clusters were cooled extensively in the supersonic expansion [T(translational) 1 to 4 K, T(rotational) = 4 K, T(vibrational) = 20 to 70 K]. These clusters were detected in the supersonic beam by laser photoionization with time-of-flight mass analysis. Using a number of fixed frequency outputs of an exciplex laser, the threshold behavior of the photoionization cross section was monitored as a function of cluster size.nce two-photon ionization (R2PI) with mass selective detection allowed the detection of five new electronic band systems in the region between 2690 and 3200 A, for each of the three naturally occurring isotopic forms of Cu 2 . In the process of scanning the R2PI spectrum of these new electronic states, the ionization potential of the copper dimer was determined to be 7.894 +- 0.015 eV

  11. Flowfield analysis of modern helicopter rotors in hover by Navier-Stokes method

    Science.gov (United States)

    Srinivasan, G. R.; Raghavan, V.; Duque, E. P. N.

    1991-01-01

    The viscous, three-dimensional, flowfields of UH60 and BERP rotors are calculated for lifting hover configurations using a Navier-Stokes computational fluid dynamics method with a view to understand the importance of planform effects on the airloads. In this method, the induced effects of the wake, including the interaction of tip vortices with successive blades, are captured as a part of the overall flowfield solution without prescribing any wake models. Numerical results in the form of surface pressures, hover performance parameters, surface skin friction and tip vortex patterns, and vortex wake trajectory are presented at two thrust conditions for UH60 and BERP rotors. Comparison of results for the UH60 model rotor show good agreement with experiments at moderate thrust conditions. Comparison of results with equivalent rectangular UH60 blade and BERP blade indicates that the BERP blade, with an unconventional planform, gives more thrust at the cost of more power and a reduced figure of merit. The high thrust conditions considered produce severe shock-induced flow separation for UH60 blade, while the BERP blade develops more thrust and minimal separation. The BERP blade produces a tighter tip vortex structure compared with the UH60 blade. These results and the discussion presented bring out the similarities and differences between the two rotors.

  12. A Comparison of Computed and Experimental Flowfields of the RAH-66 Helicopter

    Science.gov (United States)

    vanDam, C. P.; Budge, A. M.; Duque, E. P. N.

    1996-01-01

    This paper compares and evaluates numerical and experimental flowfields of the RAH-66 Comanche helicopter. The numerical predictions were obtained by solving the Thin-Layer Navier-Stokes equations. The computations use actuator disks to investigate the main and tail rotor effects upon the fuselage flowfield. The wind tunnel experiment was performed in the 14 x 22 foot facility located at NASA Langley. A suite of flow conditions, rotor thrusts and fuselage-rotor-tail configurations were tested. In addition, the tunnel model and the computational geometry were based upon the same CAD definition. Computations were performed for an isolated fuselage configuration and for a rotor on configuration. Comparisons between the measured and computed surface pressures show areas of correlation and some discrepancies. Local areas of poor computational grid-quality and local areas of geometry differences account for the differences. These calculations demonstrate the use of advanced computational fluid dynamic methodologies towards a flight vehicle currently under development. It serves as an important verification for future computed results.

  13. Flowfield Analysis of Savonius-type Wind Turbine blade

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Tae Hyun; Chang, Se Myong [Kunsan National Univ., Kunsan (Korea, Republic of); Seo, Hyun Soo [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

    2007-07-01

    In this paper, we researched flow of 8000 {approx} 24000 Reynolds number around a blade model of Savonius-type wind turbine with experimental and numerical method. For the blade shape of arc, we analyzed flowfield with streak-image flow visualization, measured wake, computed drag coefficients, and compared them for given angle of attacks. The result of research can be used to design aerodynamic performance of Savonius-type turbine rotor directly.

  14. Supersonic impinging jet noise reduction using a hybrid control technique

    Science.gov (United States)

    Wiley, Alex; Kumar, Rajan

    2015-07-01

    Control of the highly resonant flowfield associated with supersonic impinging jet has been experimentally investigated. Measurements were made in the supersonic impinging jet facility at the Florida State University for a Mach 1.5 ideally expanded jet. Measurements included unsteady pressures on a surface plate near the nozzle exit, acoustics in the nearfield and beneath the impingement plane, and velocity field using particle image velocimetry. Both passive control using porous surface and active control with high momentum microjet injection are effective in reducing nearfield noise and flow unsteadiness over a range of geometrical parameters; however, the type of noise reduction achieved by the two techniques is different. The passive control reduces broadband noise whereas microjet injection attenuates high amplitude impinging tones. The hybrid control, a combination of two control methods, reduces both broadband and high amplitude impinging tones and surprisingly its effectiveness is more that the additive effect of the two control techniques. The flow field measurements show that with hybrid control the impinging jet is stabilized and the turbulence quantities such as streamwise turbulence intensity, transverse turbulence intensity and turbulent shear stress are significantly reduced.

  15. THERMAL AND AERODYNAMIC PERFORMANCES OF THE SUPERSONIC MOTION

    Directory of Open Access Journals (Sweden)

    Dejan P Ninković

    2010-01-01

    Full Text Available Generally speaking, Mach number of 4 can be taken as a boundary value for transition from conditions for supersonic, into the area of hypersonic flow, distinguishing two areas: area of supersonic in which the effects of the aerodynamic heating can be neglected and the area of hypersonic, in which the thermal effects become dominant. This paper presents the effects in static and dynamic areas, as well as presentation of G.R.O.M. software for determination of the values of aerodynamic derivatives, which was developed on the basis of linearized theory of supersonic flow. Validation of developed software was carried out through different types of testing, proving its usefulness for engineering practice in the area of supersonic wing aerodynamic loading calculations, even at high Mach numbers, with dominant thermal effects.

  16. Entropy Minimization Design Approach of Supersonic Internal Passages

    Directory of Open Access Journals (Sweden)

    Jorge Sousa

    2015-08-01

    Full Text Available Fluid machinery operating in the supersonic regime unveil avenues towards more compact technology. However, internal supersonic flows are associated with high aerodynamic and thermal penalties, which usually prevent their practical implementation. Indeed, both shock losses and the limited operational range represent particular challenges to aerodynamic designers that should be taken into account at the initial phase of the design process. This paper presents a design methodology for supersonic passages based on direct evaluations of the velocity field using the method of characteristics and computation of entropy generation across shock waves. This meshless function evaluation tool is then coupled to an optimization scheme, based on evolutionary algorithms that minimize the entropy generation across the supersonic passage. Finally, we assessed the results with 3D Reynolds Averaged Navier Stokes calculations.

  17. Study on thermal-hydraulic behavior in supersonic steam injector

    International Nuclear Information System (INIS)

    Abe, Yutaka; Fukuichi, Akira; Kawamoto, Yujiro; Iwaki, Chikako; Narabayashi, Tadashi; Mori, Michitsugu; Ohmori, Shuichi

    2007-01-01

    Supersonic steam injector is the one of the most possible devices aiming at simplifying system and improving the safety and the credibility for next-generation nuclear reactor systems. The supersonic steam injector has dual functions of a passive jet pump without rotating machine and a compact and high efficiency heat exchanger, because it is operated by the direct contact condensation between supersonic steam and subcooled water jet. It is necessary to clarify the flow behavior in the supersonic steam injector which is governed by the complicated turbulent flow with a great shear stress of supersonic steam. However, in previous study, there is little study about the turbulent heat transfer and flow behavior under such a great shear stress at the gas-liquid interface. In the present study, turbulent flow behavior including the effect of the interface between water jet and supersonic steam is developed based on the eddy viscosity model. Radial velocity distributions and the turbulent heat transfer are calculated with the model. The calculation results are compared with the experimental results done with the transparent steam injector. (author)

  18. High-magnification velocity field measurements on high-frequency, supersonic microactuators

    Science.gov (United States)

    Kreth, Phil; Fernandez, Erik; Ali, Mohd; Alvi, Farrukh

    2014-11-01

    The Resonance-Enhanced Microjet (REM) actuator developed at our laboratory produces pulsed, supersonic microjets by utilizing a number of microscale, flow-acoustic resonance phenomena. The microactuator used in this study consists of an underexpanded source jet flowing into a cylindrical cavity with a single orifice through which an unsteady, supersonic jet issues at a resonant frequency of 7 kHz. The flowfields of a 1 mm underexpanded free jet and the microactuator are studied in detail using high-magnification, phase-locked flow visualizations (microschlieren) and 2-component particle image velocimetry. The challenges of these measurements at such small scales and supersonic velocities are discussed. The results clearly show that the microactuator produces supersonic pulsed jets with velocities exceeding 400 m/s. This is the first direct measurement of the velocity field and its temporal evolution produced by such actuators. Comparisons are made between the flow visualizations, velocity field measurements, and simulations using Implicit LES for a similar microactuator. With high, unsteady momentum output, this type of microactuator has potential in a range of flow control applications.

  19. CAN-DO, CFD-based Aerodynamic Nozzle Design and Optimization program for supersonic/hypersonic wind tunnels

    Science.gov (United States)

    Korte, John J.; Kumar, Ajay; Singh, D. J.; White, J. A.

    1992-01-01

    A design program is developed which incorporates a modern approach to the design of supersonic/hypersonic wind-tunnel nozzles. The approach is obtained by the coupling of computational fluid dynamics (CFD) with design optimization. The program can be used to design a 2D or axisymmetric, supersonic or hypersonic, wind-tunnel nozzles that can be modeled with a calorically perfect gas. The nozzle design is obtained by solving a nonlinear least-squares optimization problem (LSOP). The LSOP is solved using an iterative procedure which requires intermediate flowfield solutions. The nozzle flowfield is simulated by solving the Navier-Stokes equations for the subsonic and transonic flow regions and the parabolized Navier-Stokes equations for the supersonic flow regions. The advantages of this method are that the design is based on the solution of the viscous equations eliminating the need to make separate corrections to a design contour, and the flexibility of applying the procedure to different types of nozzle design problems.

  20. Effect of swirling device on flow behavior in a supersonic separator for natural gas dehydration

    DEFF Research Database (Denmark)

    Wen, Chuang; Li, Anqi; Walther, Jens Honore

    2016-01-01

    is designed for an annular supersonic separator. The supersonic swirling separation flow of natural gas is calculated using the Reynolds Stress model. The results show that the viscous heating and strong swirling flow cause the adverse pressure in the annular channel, which may negatively affect......The supersonic separator is a revolutionary device to remove the condensable components from gas mixtures. One of the key issues for this novel technology is the complex supersonic swirling flow that is not well understood. A swirling device composed of an ellipsoid and several helical blades...

  1. Continuous supersonic plasma wind tunnel

    DEFF Research Database (Denmark)

    Andersen, S.A.; Jensen, Vagn Orla; Nielsen, P.

    1969-01-01

    The normal magnetic field configuration of a Q device has been modified to obtain a 'magnetic Laval nozzle'. Continuous supersonic plasma 'winds' are obtained with Mach numbers ~3. The magnetic nozzle appears well suited for the study of the interaction of supersonic plasma 'winds' with either...

  2. Continuous supersonic plasma wind tunnel

    DEFF Research Database (Denmark)

    Andersen, S.A.; Jensen, Vagn Orla; Nielsen, P.

    1968-01-01

    The B field configuration of a Q-device has been modified into a magnetic Laval nozzle. Continuous supersonic plasma flow is observed with M≈3......The B field configuration of a Q-device has been modified into a magnetic Laval nozzle. Continuous supersonic plasma flow is observed with M≈3...

  3. The Edge supersonic transport

    Science.gov (United States)

    Agosta, Roxana; Bilbija, Dushan; Deutsch, Marc; Gallant, David; Rose, Don; Shreve, Gene; Smario, David; Suffredini, Brian

    1992-01-01

    As intercontinental business and tourism volumes continue their rapid expansion, the need to reduce travel times becomes increasingly acute. The Edge Supersonic Transport Aircraft is designed to meet this demand by the year 2015. With a maximum range of 5750 nm, a payload of 294 passengers and a cruising speed of M = 2.4, The Edge will cut current international flight durations in half, while maintaining competitive first class, business class, and economy class comfort levels. Moreover, this transport will render a minimal impact upon the environment, and will meet all Federal Aviation Administration Part 36, Stage III noise requirements. The cornerstone of The Edge's superior flight performance is its aerodynamically efficient, dual-configuration design incorporating variable-geometry wingtips. This arrangement combines the benefits of a high aspect ratio wing at takeoff and low cruising speeds with the high performance of an arrow-wing in supersonic cruise. And while the structural weight concerns relating to swinging wingtips are substantial, The Edge looks to ever-advancing material technologies to further increase its viability. Heeding well the lessons of the past, The Edge design holds economic feasibility as its primary focus. Therefore, in addition to its inherently superior aerodynamic performance, The Edge uses a lightweight, largely windowless configuration, relying on a synthetic vision system for outside viewing by both pilot and passengers. Additionally, a fly-by-light flight control system is incorporated to address aircraft supersonic cruise instability. The Edge will be produced at an estimated volume of 400 aircraft and will be offered to airlines in 2015 at $167 million per transport (1992 dollars).

  4. A second-generation supersonic transport

    Science.gov (United States)

    Humphrey, W.; Grayson, G.; Gump, J.; Hutko, G.; Kubicko, R.; Obrien, J.; Orndorff, R.; Oscher, R.; Polster, M.; Ulrich, C.

    1989-01-01

    already existing technology. This is of particular importance with respect to support technology such as airport terminals and runways. Based on the above introductory remarks, a possible approach to the design of a second-generation supersonic civil transport is presented here. The design Mach number for this aircraft is 3.5. This value was chosen as it represents the limiting Mach number in the absence of active cooling. The ensuing design attempts to deal with the particular problems that are the most demanding, while relying on proven technology where it is adequate. The report clearly does not solve, or even deal with, every aspect of the aircraft design. Rather, a general direction is suggested and supported with initial, approximate calculations.

  5. Development and operation of an integrated sampling probe and gas analyzer for turbulent mixing studies in complex supersonic flows

    Science.gov (United States)

    Wiswall, John D.

    For many aerospace applications, mixing enhancement between co-flowing streams has been identified as a critical and enabling technology. Due to short fuel residence times in scramjet combustors, combustion is limited by the molecular mixing of hydrogen (fuel) and air. Determining the mixedness of fuel and air in these complex supersonic flowfields is critical to the advancement of novel injection schemes currently being developed at UTA in collaboration with NASA Langley and intended to be used on a future two-stage to orbit (~Mach 16) hypersonic air-breathing vehicle for space access. Expanding on previous work, an instrument has been designed, fabricated, and tested in order to measure mean concentrations of injected helium (a passive scalar used instead of hazardous hydrogen) and to quantitatively characterize the nature of the high-frequency concentration fluctuations encountered in the compressible, turbulent, and high-speed (up to Mach 3.5) complex flows associated with the new supersonic injection schemes. This important high-frequency data is not yet attainable when employing other techniques such as Laser Induced Fluorescence, Filtered Rayleigh Scattering or mass spectroscopy in the same complex supersonic flows. The probe operates by exploiting the difference between the thermodynamic properties of two species through independent massflow measurements and calibration. The probe samples isokinetically from the flowfield's area of interest and the helium concentration may be uniquely determined by hot-film anemometry and internally measured stagnation conditions. The final design has a diameter of 0.25" and is only 2.22" long. The overall accuracy of the probe is 3% in molar fraction of helium. The frequency response of mean concentration measurements is estimated at 103 Hz, while high-frequency hot-film measurements were conducted at 60 kHz. Additionally, the work presents an analysis of the probe's internal mixing effects and the effects of the spatial

  6. CFD flowfield simulation of Delta Launch Vehicles in a power-on configuration

    Science.gov (United States)

    Pavish, D. L.; Gielda, T. P.; Soni, B. K.; Deese, J. E.; Agarwal, R. K.

    1993-01-01

    This paper summarizes recent work at McDonnell Douglas Aerospace (MDA) to develop and validate computational fluid dynamic (CFD) simulations of under expanded rocket plume external flowfields for multibody expendable launch vehicles (ELVs). Multi engine reacting gas flowfield predictions of ELV base pressures are needed to define vehicle base drag and base heating rates for sizing external nozzle and base region insulation thicknesses. Previous ELV design programs used expensive multibody power-on wind tunnel tests that employed chamber/nozzle injected high pressure cold or hot-air. Base heating and pressure measurements were belatedly made during the first flights of past ELV's to correct estimates from semi-empirical engineering models or scale model tests. Presently, CFD methods for use in ELV design are being jointly developed at the Space Transportation Division (MDA-STD) and New Aircraft Missiles Division (MDA-NAMD). An explicit three dimensional, zonal, finite-volume, full Navier-Stokes (FNS) solver with finite rate hydrocarbon/air and aluminum combustion kinetics was developed to accurately compute ELV power-on flowfields. Mississippi State University's GENIE++ general purpose interactive grid generation code was chosen to create zonal, finite volume viscous grids. Axisymmetric, time dependent, turbulent CFD simulations of a Delta DSV-2A vehicle with a MB-3 liquid main engine burning RJ-1/LOX were first completed. Hydrocarbon chemical kinetics and a k-epsilon turbulence model were employed and predictions were validated with flight measurements of base pressure and temperature. Zonal internal/external grids were created for a Delta DSV-2C vehicle with a MB-3 and three Castor-1 solid motors burning and a Delta-2 with an RS-27 main engine (LOX/RP-1) and 9 GEM's attached/6 burning. Cold air, time dependent FNS calculations were performed for DSV-2C during 1992. Single phase simulations that employ finite rate hydrocarbon and aluminum (solid fuel) combustion

  7. Supersonic flow with shock waves. Monte-Carlo calculations for low density plasma. I; Flujo supersonico de un plasma con ondas de choque, un metodo de montecarlo para plasmas de baja densidad, I.

    Energy Technology Data Exchange (ETDEWEB)

    Almenara, E; Hidalgo, M; Saviron, J M

    1980-07-01

    This Report gives preliminary information about a Monte Carlo procedure to simulate supersonic flow past a body of a low density plasma in the transition regime. A computer program has been written for a UNIVAC 1108 machine to account for a plasma composed by neutral molecules and positive and negative ions. Different and rather general body geometries can be analyzed. Special attention is played to tho detached shock waves growth In front of the body. (Author) 30 refs.

  8. Two-dimensional unsteady lift problems in supersonic flight

    Science.gov (United States)

    Heaslet, Max A; Lomax, Harvard

    1949-01-01

    The variation of pressure distribution is calculated for a two-dimensional supersonic airfoil either experiencing a sudden angle-of-attack change or entering a sharp-edge gust. From these pressure distributions the indicial lift functions applicable to unsteady lift problems are determined for two cases. Results are presented which permit the determination of maximum increment in lift coefficient attained by an unrestrained airfoil during its flight through a gust. As an application of these results, the minimum altitude for safe flight through a specific gust is calculated for a particular supersonic wing of given strength and wing loading.

  9. Active Control of Supersonic Impinging Jets Using Supersonic Microjets

    National Research Council Canada - National Science Library

    Alvi, Farrukh

    2005-01-01

    .... Supersonic impinging jets occur in many applications including in STOVL aircraft where they lead to a highly oscillatory flow with very high unsteady loads on the nearby aircraft structures and the landing surfaces...

  10. Detonation in supersonic radial outflow

    KAUST Repository

    Kasimov, Aslan R.; Korneev, Svyatoslav

    2014-01-01

    We report on the structure and dynamics of gaseous detonation stabilized in a supersonic flow emanating radially from a central source. The steady-state solutions are computed and their range of existence is investigated. Two-dimensional simulations

  11. Supersonic induction plasma jet modeling

    International Nuclear Information System (INIS)

    Selezneva, S.E.; Boulos, M.I.

    2001-01-01

    Numerical simulations have been applied to study the argon plasma flow downstream of the induction plasma torch. It is shown that by means of the convergent-divergent nozzle adjustment and chamber pressure reduction, a supersonic plasma jet can be obtained. We investigate the supersonic and a more traditional subsonic plasma jets impinging onto a normal substrate. Comparing to the subsonic jet, the supersonic one is narrower and much faster. Near-substrate velocity and temperature boundary layers are thinner, so the heat flux near the stagnation point is higher in the supersonic jet. The supersonic plasma jet is characterized by the electron overpopulation and the domination of the recombination over the dissociation, resulting into the heating of the electron gas. Because of these processes, the supersonic induction plasma permits to separate spatially different functions (dissociation and ionization, transport and deposition) and to optimize each of them. The considered configuration can be advantageous in some industrial applications, such as plasma-assisted chemical vapor deposition of diamond and polymer-like films and in plasma spraying of nanoscaled powders

  12. Flow control of micro-ramps on supersonic forward-facing step flow

    International Nuclear Information System (INIS)

    Zhang Qing-Hu; Zhu Tao; Wu Anping; Yi Shihe

    2016-01-01

    The effects of the micro-ramps on supersonic turbulent flow over a forward-facing step (FFS) was experimentally investigated in a supersonic low-noise wind tunnel at Mach number 3 using nano-tracer planar laser scattering (NPLS) and particle image velocimetry (PIV) techniques. High spatiotemporal resolution images and velocity fields of supersonic flow over the testing model were captured. The fine structures and their spatial evolutionary characteristics without and with the micro-ramps were revealed and compared. The large-scale structures generated by the micro-ramps can survive the downstream FFS flowfield. The micro-ramps control on the flow separation and the separation shock unsteadiness was investigated by PIV results. With the micro-ramps, the reduction in the range of the reversal flow zone in streamwise direction is 50% and the turbulence intensity is also reduced. Moreover, the reduction in the average separated region and in separation shock unsteadiness are 47% and 26%, respectively. The results indicate that the micro-ramps are effective in reducing the flow separation and the separation shock unsteadiness. (paper)

  13. Tangential inlet supersonic separators: a novel apparatus for gas purification

    DEFF Research Database (Denmark)

    Wen, Chuang; Walther, Jens Honore; Yang, Yan

    2016-01-01

    A novel supersonic separator with a tangential inlet is designed to remove the condensable components from gas mixtures. The dynamic parameters of natural gas in the supersonic separation process are numerically calculated using the Reynolds stress turbulence model with the Peng-Robinson real gas...... be generated by the tangential inlet, and it increases to the maximum of 200 m/s at the nozzle throat due to decrease of the nozzle area of the converging part. The tangential velocity can maintain the value of about 160 m/s at the nozzle exit, and correspondingly generates the centrifugal acceleration of 3...

  14. Numerical Simulation of the Aircraft Wake Vortex Flowfield

    Science.gov (United States)

    Ahmad, Nashat N.; Proctor, Fred H.; Perry, R. Brad

    2013-01-01

    The near wake vortex flowfield from a NACA0012 half-wing was simulated using a fully unstructured Navier-Stokes flow solver in three dimensions at a chord Reynolds number of 4.6 million and a Mach number of approximately 0.15. Several simulations were performed to examine the effect of boundary conditions, mesh resolution and turbulence scheme on the formation of wingtip vortex and its downstream propagation. The standard Spalart-Allmaras turbulence model was compared with the Dacles-Mariani and Spalart-Shur corrections for rotation and curvature effects. The simulation results were evaluated using the data from experiment performed at NASA Ames' 32in x 48in low speed wind tunnel.

  15. Non-Intrusive Optical Diagnostic Methods for Flowfield Characterization

    Science.gov (United States)

    Tabibi, Bagher M.; Terrell, Charles A.; Spraggins, Darrell; Lee, Ja. H.; Weinstein, Leonard M.

    1997-01-01

    Non-intrusive optical diagnostic techniques such as Electron Beam Fluorescence (EBF), Laser-Induced Fluorescence (LIF), and Focusing Schlieren (FS) have been setup for high-speed flow characterization and large flowfield visualization, respectively. Fluorescence emission from the First Negative band of N2(+) with the (0,0) vibration transition (at lambda =391.44 nm) was obtained using the EBF technique and a quenching rate of N2(+)* molecules by argon gas was reported. A very high sensitivity FS system was built and applied in the High-Speed Flow Generator (HFG) at NASA LaRC. A LIF system is available at the Advanced Propulsion Laboratory (APL) on campus and a plume exhaust velocity measurement, measuring the Doppler shift from lambda = 728.7 nm of argon gas, is under way.

  16. Experimental investigation of the flowfield of an oscillating airfoil

    Science.gov (United States)

    Panda, J.; Zaman, K. B. M. Q.

    1992-01-01

    The flowfield of an airfoil oscillated periodically over a wide range of reduced frequencies, 0 less than or = k less than or = 1.6 is studied experimentally at chord Reynolds numbers of R sub c = 22,000 and 44,000. The NACA0012 airfoil is pitched sinusoidally about one quarter chord between angles of attack (alpha) of 5 and 25 degrees. Detailed flow visualization and phase averaged vorticity measurements are carried out for k = 0.2 to document the evolution and the shedding of the dynamic stall vortex (DSV). In addition to the DSV, an intense vortex of opposite sign originates from the trailing edge just when the DSV is shed. After being shed into the wake, the two together take the shape of a large 'mushroom' while being convected away from the airfoil. The unsteady circulation around the airfoil and, therefore, the time varying component of the lift is estimated in a novel way from the shed vorticity flux and is found to be in good agreement with the lift variation reported by others. The delay in the shedding of the DSV with increasing k, as observed by previous researchers, is documented for the full range of k. The DSV, for example, is shed nearly at the maximum alpha of 25 degrees at k = 0.2, but is shed at the minimum alpha of 5 degrees at k = 0.8. At low k, the flowfield appears quasi-steady and the bluff body shedding corresponding to the maximum alpha (25 degrees) dominates the unsteady fluctuations in the wake.

  17. Numerical and Experimental Investigation of a Supersonic Flow Field around Solid Fuel on an Inclined Flat Plate

    Directory of Open Access Journals (Sweden)

    Uzu-Kuei Hsu

    2009-01-01

    Full Text Available This research adopts a shock tube 16 meters long and with a 9 cm bore to create a supersonic, high-temperature, and high-pressure flowfield to observe the gasification and ignition of HTPB solid fuel under different environments. Also, full-scale 3D numerical simulation is executed to enhance the comprehension of this complex phenomenon. The CFD (Computational Fluid Dynamics code is based on the control volume method and the pre-conditioning method for solving the Navier-Stokes equations to simulate the compressible and incompressible coupling problem. In the tests, a HTPB slab is placed in the windowed-test section. Various test conditions generate different supersonic Mach numbers and environmental temperatures. In addition, the incident angles of the HTPB slab were changed relative to the incoming shock wave. Results show that as the Mach number around the slab section exceeded 1.25, the flowfield temperature achieved 1100 K, which is higher than the HTPB gasification temperature (930 K ~ 1090 K. Then, gasification occurred and a short-period ignition could be observed. In particular, when the slab angle was 7∘, the phenomenon became more visible. This is due to the flow field temperature increase when the slab angle was at 7∘.

  18. Store Separations From a Supersonic Cone

    National Research Council Canada - National Science Library

    Simko, Richard J

    2006-01-01

    ... analyses of supersonic store separations. Also included in this research is a study of supersonic base pressure profiles, near-wake velocity profiles, wind tunnel shock interactions and force/moment studies on a conical store and parent vehicle...

  19. The impact of channel path length on PEMFC flow-field design

    Energy Technology Data Exchange (ETDEWEB)

    Shimpalee, S.; Greenway, S.; Van Zee, J.W. [Chemical Engineering Department, University of South Carolina, Columbia, SC 29208 (United States)

    2006-09-29

    Distributions in reactant species concentration in a PEMFC due to local consumption of fuel and local transport of water through the membrane cause distributions in current density, temperature, and water concentration in three dimensions in a PEMFC. These distributions can lead to flooding or drying of the membrane that may shorten the life of an MEA. Changing the cell's flow-field pattern to distribute the gas more evenly is one method of minimizing these stresses. This paper investigates how 200cm{sup 2} serpentine flow-fields with different number of gas paths, and thus different gas path lengths, affect performance and species distribution. The results show how the local temperature, water content, and current density distributions become more uniform for serpentine flow-field designs with shorter path lengths or larger number of channels. These results may be used to develop universal heuristics and dimensionless number correlations in the design of flow-fields and stacks. (author)

  20. Design and Calibration of a Flowfield Survey Rake for Inlet Flight Research

    Science.gov (United States)

    Flynn, Darin C.; Ratnayake, Nalin A.; Frederick, Michael

    2009-01-01

    Flowfield rake was designed to quantify the flowfield for inlet research underneath NASA DFRC s F-15B airplane. Detailed loads and stress analysis performed using CFD and empirical methods to assure structural integrity. Calibration data were generated through wind tunnel testing of the rake. Calibration algorithm was developed to determine the local Mach and flow angularity at each probe. RAGE was flown November, 2008. Data is currently being analyzed.

  1. Supersonic propulsion technology. [variable cycle engines

    Science.gov (United States)

    Powers, A. G.; Coltrin, R. E.; Stitt, L. E.; Weber, R. J.; Whitlow, J. B., Jr.

    1979-01-01

    Propulsion concepts for commercial supersonic transports are discussed. It is concluded that variable cycle engines, together with advanced supersonic inlets and low noise coannular nozzles, provide good operating performance for both supersonic and subsonic flight. In addition, they are reasonably quiet during takeoff and landing and have acceptable exhaust emissions.

  2. High-fidelity large eddy simulation for supersonic jet noise prediction

    Science.gov (United States)

    Aikens, Kurt M.

    The problem of intense sound radiation from supersonic jets is a concern for both civil and military applications. As a result, many experimental and computational efforts are focused at evaluating possible noise suppression techniques. Large-eddy simulation (LES) is utilized in many computational studies to simulate the turbulent jet flowfield. Integral methods such as the Ffowcs Williams-Hawkings (FWH) method are then used for propagation of the sound waves to the farfield. Improving the accuracy of this two-step methodology and evaluating beveled converging-diverging nozzles for noise suppression are the main tasks of this work. First, a series of numerical experiments are undertaken to ensure adequate numerical accuracy of the FWH methodology. This includes an analysis of different treatments for the downstream integration surface: with or without including an end-cap, averaging over multiple end-caps, and including an approximate surface integral correction term. Secondly, shock-capturing methods based on characteristic filtering and adaptive spatial filtering are used to extend a highly-parallelizable multiblock subsonic LES code to enable simulations of supersonic jets. The code is based on high-order numerical methods for accurate prediction of the acoustic sources and propagation of the sound waves. Furthermore, this new code is more efficient than the legacy version, allows cylindrical multiblock topologies, and is capable of simulating nozzles with resolved turbulent boundary layers when coupled with an approximate turbulent inflow boundary condition. Even though such wall-resolved simulations are more physically accurate, their expense is often prohibitive. To make simulations more economical, a wall model is developed and implemented. The wall modeling methodology is validated for turbulent quasi-incompressible and compressible zero pressure gradient flat plate boundary layers, and for subsonic and supersonic jets. The supersonic code additions and the

  3. Numerical Investigation of the Interaction of Counterflowing Jets and Supersonic Capsule Flows

    Science.gov (United States)

    Venkatachari, Balaji Shankar; Ito, Yasushi; Cheng, Gary; Chang, Chau-Lyan

    2011-01-01

    Use of counterflowing jets ejected into supersonic freestreams as a flow control concept to modify the external flowfield has gained renewed interest with regards to potential retropropulsion applications pertinent to entry, descent, and landing investigations. This study describes numerical computations of such a concept for a scaled wind-tunnel capsule model by employing the space-time conservation element solution element viscous flow solver with unstructured meshes. Both steady-state and time-accurate computations are performed for several configurations with different counterflowing jet Mach numbers. Axisymmetric computations exploring the effect of the jet flow rate and jet Mach number on the flow stability, jet interaction with the bow shock and its subsequent impact on the aerodynamic and aerothermal loads on the capsule body are carried out. Similar to previous experimental findings, both long and short penetration modes exist at a windtunnel Mach number of 3.48. It was found that both modes exhibit non-stationary behavior and the former is much more unstable than the latter. It was also found that the unstable long penetration mode only exists in a relatively small range of the jet mass flow rate. Solution-based mesh refinement procedures are used to improve solution accuracy and provide guidelines for a more effective mesh generation procedure for parametric studies. Details of the computed flowfields also serve as a means to broaden the knowledge base for future retropropulsion design studies.

  4. A study of air breathing rockets. 3: Supersonic mode combustors

    Science.gov (United States)

    Masuya, G.; Chinzel, N.; Kudo, K.; Murakami, A.; Komuro, T.; Ishii, S.

    An experimental study was made on supersonic mode combustors of an air breathing rocket engine. Supersonic streams of room-temperature air and hot fuel-rich rocket exhaust were coaxially mixed and burned in a concially diverging duct of 2 deg half-angle. The effect of air inlet Mach number and excess air ratio was investigated. Axial wall pressure distribution was measured to calculate one dimensional change of Mach number and stagnation temperature. Calculated results showed that supersonic combustion occurred in the duct. At the exit of the duct, gas sampling and Pitot pressure measurement was made, from which radial distributions of various properties were deduced. The distribution of mass fraction of elements from rocket exhaust showed poor mixing performance in the supersonic mode combustors compared with the previously investigated cylindrical subsonic mode combustors. Secondary combustion efficiency correlated well with the centerline mixing parameter, but not with Annushkin's non-dimensional combustor length. No major effect of air inlet Mach number or excess air ratio was seen within the range of conditions under which the experiment was conducted.

  5. Improved Flow-Field Structures for Direct Methanol Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Gurau, Bogdan [Nuvant Systems Inc., Crown Point, IN (United States)

    2013-05-31

    The direct methanol fuel cell (DMFC) is ideal if high energy-density liquid fuels are required. Liquid fuels have advantages over compressed hydrogen including higher energy density and ease of handling. Although state-of-the-art DMFCs exhibit manageable degradation rates, excessive fuel crossover diminishes system energy and power density. Although use of dilute methanol mitigates crossover, the concomitant lowering of the gross fuel energy density (GFED) demands a complex balance-of-plant (BOP) that includes higher flow rates, external exhaust recirculation, etc. An alternative approach is redesign of the fuel delivery system to accommodate concentrated methanol. NuVant Systems Inc. (NuVant) will maximize the GFED by design and assembly of a DMFC that uses near neat methanol. The approach is to tune the diffusion of highly concentrated methanol (to the anode catalytic layer) to the back-diffusion of water formed at the cathode (i.e. in situ generation of dilute methanol at the anode layer). Crossover will be minimized without compromising the GFED by innovative integration of the anode flow-field and the diffusion layer. The integrated flow-field-diffusion-layers (IFDLs) will widen the current and potential DMFC operating ranges and enable the use of cathodes optimized for hydrogen-air fuel cells.

  6. Influence of flowfield and vehicle parameters on engineering aerothermal methods

    Science.gov (United States)

    Wurster, Kathryn E.; Zoby, E. Vincent; Thompson, Richard A.

    1989-01-01

    The reliability and flexibility of three engineering codes used in the aerosphace industry (AEROHEAT, INCHES, and MINIVER) were investigated by comparing the results of these codes with Reentry F flight data and ground-test heat-transfer data for a range of cone angles, and with the predictions obtained using the detailed VSL3D code; the engineering solutions were also compared. In particular, the impact of several vehicle and flow-field parameters on the heat transfer and the capability of the engineering codes to predict these results were determined. It was found that entropy, pressure gradient, nose bluntness, gas chemistry, and angle of attack all affect heating levels. A comparison of the results of the three engineering codes with Reentry F flight data and with the predictions obtained of the VSL3D code showed a very good agreement in the regions of the applicability of the codes. It is emphasized that the parameters used in this study can significantly influence the actual heating levels and the prediction capability of a code.

  7. Direct formulation of the supersonic acoustic intensity in space domain

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn; Leclre, Quentin

    2012-01-01

    into the far field. To date, its calculation has been formulated in the wave number domain, filtering out the evanescent waves outside the radiation circle and reconstructing the acoustic field with only the propagating waves. In this study, the supersonic intensity is calculated directly in space domain......This paper proposes and examines a direct formulation in space domain of the so-called supersonic acoustic intensity. This quantity differs from the usual (active) intensity by excluding the circulating energy in the near-field of the source, providing a map of the acoustic energy that is radiated...... by means of a two-dimensional convolution between the acoustic field and a spatial filter mask that corresponds to the space domain representation of the radiation circle. Therefore, the acoustic field that propagates effectively to the far field is calculated via direct filtering in space domain...

  8. The Intensity of the Light Diffraction by Supersonic Longitudinal Waves in Solid

    Directory of Open Access Journals (Sweden)

    Minasyan V.

    2010-04-01

    Full Text Available First, we predict existence of transverse electromagnetic field created by supersonic longitudinal waves in solid. This electromagnetic wave with frequency of ultrasonic field is moved by velocity of supersonic field toward of direction propagation of one. The average Poynting vector of superposition field is calculated by presence of the transverse electromagnetic and the optical fields which in turn provides appearance the diffraction of light.

  9. Decoding complex flow-field patterns in visual working memory.

    Science.gov (United States)

    Christophel, Thomas B; Haynes, John-Dylan

    2014-05-01

    There has been a long history of research on visual working memory. Whereas early studies have focused on the role of lateral prefrontal cortex in the storage of sensory information, this has been challenged by research in humans that has directly assessed the encoding of perceptual contents, pointing towards a role of visual and parietal regions during storage. In a previous study we used pattern classification to investigate the storage of complex visual color patterns across delay periods. This revealed coding of such contents in early visual and parietal brain regions. Here we aim to investigate whether the involvement of visual and parietal cortex is also observable for other types of complex, visuo-spatial pattern stimuli. Specifically, we used a combination of fMRI and multivariate classification to investigate the retention of complex flow-field stimuli defined by the spatial patterning of motion trajectories of random dots. Subjects were trained to memorize the precise spatial layout of these stimuli and to retain this information during an extended delay. We used a multivariate decoding approach to identify brain regions where spatial patterns of activity encoded the memorized stimuli. Content-specific memory signals were observable in motion sensitive visual area MT+ and in posterior parietal cortex that might encode spatial information in a modality independent manner. Interestingly, we also found information about the memorized visual stimulus in somatosensory cortex, suggesting a potential crossmodal contribution to memory. Our findings thus indicate that working memory storage of visual percepts might be distributed across unimodal, multimodal and even crossmodal brain regions. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Investigating the Structures of Turbulence in a Multi-Stream, Rectangular, Supersonic Jet

    Science.gov (United States)

    Magstadt, Andrew S.

    Supersonic flight has become a standard for military aircraft, and is being seriously reconsidered for commercial applications. Engine technologies, enabling increased mission capabilities and vehicle performance, have evolved nozzles into complex geometries with intricate flow features. These engineering solutions have advanced at a faster rate than the understanding of the flow physics, however. The full consequences of the flow are thus not known, and using predictive tools becomes exceedingly difficult. Additionally, the increasing velocities associated with supersonic flight exacerbate the preexisting jet noise problem, which has troubled the engineering community for nearly 65 years. Even in the simplest flows, the full consequences of turbulence, e.g. noise production, are not fully understood. For composite flows, the fluid mechanics and acoustic properties have been studied even less sufficiently. Before considering the aeroacoustic problem, the development, structure, and evolution of the turbulent flow-field must be considered. This has prompted an investigation into the compressible flow of a complex nozzle. Experimental evidence is sought to explain the stochastic processes of the turbulent flow issuing from a complex geometry. Before considering the more complicated configuration, an experimental campaign of an axisymmetric jet is conducted. The results from this study are presented, and guide research of the primary flow under investigation. The design of a nozzle representative of future engine technologies is then discussed. Characteristics of this multi-stream rectangular supersonic nozzle are studied via time-resolved schlieren imaging, stereo PIV measurements, dynamic pressure transducers, and far-field acoustics. Experiments are carried out in the anechoic chamber at Syracuse University, and focus primarily on the flow-field. An extensive data set is generated, which reveals a detailed view of a very complex flow. Shear, shock waves, unequal

  11. Premixed Supersonic Combustion (Rev)

    Science.gov (United States)

    2015-02-20

    calculated using the 1-D separated flow model for the isolator described in Heiser and Pratt (Ref. 19). Several curves are shown. The green curve corresponds...Report 88-3059, 1988. [18] Krauss, R.H. and McDaniel, J.C., “A Clean Air Continuous Flow Propulsion Facility,” AIAA Report 92-3912, 1992. [19] Heiser

  12. Turbulence models in supersonic flows

    International Nuclear Information System (INIS)

    Shirani, E.; Ahmadikia, H.; Talebi, S.

    2001-05-01

    The aim of this paper is to evaluate five different turbulence models when used in rather complicated two-dimensional and axisymmetric supersonic flows. They are Baldwin-Lomax, k-l, k-ε, k-ω and k-ζ turbulence models. The compressibility effects, axisymmetric correction terms and some modifications for transition region are used and tested in the models. Two computer codes based on the control volume approach and two flux-splitting methods. Roe and Van Leer, are developed. The codes are used to simulate supersonic mixing layers, flow behind axisymmetric body, under expanded jet, and flow over hollow cylinder flare. The results are compared with experimental data and behavior of the turbulence models is examined. It is shown that both k-l and k-ζ models produce very good results. It is also shown that the compressibility correction in the model is required to obtain more accurate results. (author)

  13. Advanced supersonic propulsion study, phase 3

    Science.gov (United States)

    Howlett, R. A.; Johnson, J.; Sabatella, J.; Sewall, T.

    1976-01-01

    The variable stream control engine is determined to be the most promising propulsion system concept for advanced supersonic cruise aircraft. This concept uses variable geometry components and a unique throttle schedule for independent control of two flow streams to provide low jet noise at takeoff and high performance at both subsonic and supersonic cruise. The advanced technology offers a 25% improvement in airplane range and an 8 decibel reduction in takeoff noise, relative to first generation supersonic turbojet engines.

  14. Modeling two-phase flow in three-dimensional complex flow-fields of proton exchange membrane fuel cells

    Science.gov (United States)

    Kim, Jinyong; Luo, Gang; Wang, Chao-Yang

    2017-10-01

    3D fine-mesh flow-fields recently developed by Toyota Mirai improved water management and mass transport in proton exchange membrane (PEM) fuel cell stacks, suggesting their potential value for robust and high-power PEM fuel cell stack performance. In such complex flow-fields, Forchheimer's inertial effect is dominant at high current density. In this work, a two-phase flow model of 3D complex flow-fields of PEMFCs is developed by accounting for Forchheimer's inertial effect, for the first time, to elucidate the underlying mechanism of liquid water behavior and mass transport inside 3D complex flow-fields and their adjacent gas diffusion layers (GDL). It is found that Forchheimer's inertial effect enhances liquid water removal from flow-fields and adds additional flow resistance around baffles, which improves interfacial liquid water and mass transport. As a result, substantial improvements in high current density cell performance and operational stability are expected in PEMFCs with 3D complex flow-fields, compared to PEMFCs with conventional flow-fields. Higher current density operation required to further reduce PEMFC stack cost per kW in the future will necessitate optimizing complex flow-field designs using the present model, in order to efficiently remove a large amount of product water and hence minimize the mass transport voltage loss.

  15. Supersonic Retropropulsion Flight Test Concepts

    Science.gov (United States)

    Post, Ethan A.; Dupzyk, Ian C.; Korzun, Ashley M.; Dyakonov, Artem A.; Tanimoto, Rebekah L.; Edquist, Karl T.

    2011-01-01

    NASA's Exploration Technology Development and Demonstration Program has proposed plans for a series of three sub-scale flight tests at Earth for supersonic retropropulsion, a candidate decelerator technology for future, high-mass Mars missions. The first flight test in this series is intended to be a proof-of-concept test, demonstrating successful initiation and operation of supersonic retropropulsion at conditions that replicate the relevant physics of the aerodynamic-propulsive interactions expected in flight. Five sub-scale flight test article concepts, each designed for launch on sounding rockets, have been developed in consideration of this proof-of-concept flight test. Commercial, off-the-shelf components are utilized as much as possible in each concept. The design merits of the concepts are compared along with their predicted performance for a baseline trajectory. The results of a packaging study and performance-based trade studies indicate that a sounding rocket is a viable launch platform for this proof-of-concept test of supersonic retropropulsion.

  16. Flowfield characterisation in the wake of a low-velocity heated sphere anemometer

    Energy Technology Data Exchange (ETDEWEB)

    Olim, A.M. [Associacao para o Desenvolvimento da Aerodinamica Industrial (ADAI), Coimbra (Portugal); Riethmuller, M.L. [Von Karman Institute for Fluid Dynamics (VKI), St. Genese (Belgium); Gameiro da Silva, M.C. [Departamento de Engenharia Mecanica, Faculdade de Ciencias e Tecnologia, Universidade de Coimbra Polo II, Coimbra (Portugal)

    2002-06-01

    Heated sphere anemometers (HSA) are the most widely used instruments for low-velocity measurements in the heating, ventilation and air-conditioning industry. Experiments were conducted to characterise the flowfield around the spherically shaped sensor and upper probe assembly of a HSA. Particle image velocimetry was the main quantitative experimental technique. Measurements of the flowfield around a HSA probe and a 2:1 scaled-up model were performed in a uniform isothermal axisymmetrical jet air flow at Re around 350, based on sensor diameter, for different pitch angle incident flows. Additionally, extensive flow visualisation studies around scaled-up models of the HSA probe were performed. (orig.)

  17. Do supersonic aircraft avoid contrails?

    Directory of Open Access Journals (Sweden)

    A. Stenke

    2008-02-01

    Full Text Available The impact of a potential future fleet of supersonic aircraft on contrail coverage and contrail radiative forcing is investigated by means of simulations with the general circulation model ECHAM4.L39(DLR including a contrail parameterization. The model simulations consider air traffic inventories of a subsonic fleet and of a combined fleet of sub- and supersonic aircraft for the years 2025 and 2050, respectively. In case of the combined fleet, part of the subsonic fleet is replaced by supersonic aircraft. The combined air traffic scenario reveals a reduction in contrail cover at subsonic cruise levels (10 to 12 km in the northern extratropics, especially over the North Atlantic and North Pacific. At supersonic flight levels (18 to 20 km, contrail formation is mainly restricted to tropical regions. Only in winter is the northern extratropical stratosphere above the 100 hPa level cold enough for the formation of contrails. Total contrail coverage is only marginally affected by the shift in flight altitude. The model simulations indicate a global annual mean contrail cover of 0.372% for the subsonic and 0.366% for the combined fleet in 2050. The simulated contrail radiative forcing is most closely correlated to the total contrail cover, although contrails in the tropical lower stratosphere are found to be optically thinner than contrails in the extratropical upper troposphere. The global annual mean contrail radiative forcing in 2050 (2025 amounts to 24.7 mW m−2 (9.4 mW m−2 for the subsonic fleet and 24.2 mW m−2 (9.3 mW m−2 for the combined fleet. A reduction of the supersonic cruise speed from Mach 2.0 to Mach 1.6 leads to a downward shift in contrail cover, but does not affect global mean total contrail cover and contrail radiative forcing. Hence the partial substitution of subsonic air traffic leads to a shift of contrail occurrence from mid to low latitudes, but the resulting change in

  18. Laser Velocimeter for Studies of Microgravity Combustion Flowfields

    Science.gov (United States)

    Varghese, Philip L.

    2003-01-01

    A velocimeter was developed based on modulated filtered Rayleigh scattering (MFRS). The MFRS velocimeter was successfully demonstrated by making one-component velocity measurements in a supersonic expansion using molecular Rayleigh scattering in a jet of N2. These measurements were made in a sweep mode where the Rayleigh scattered profile is cross-correlated with absorption in a static cell to determine velocity. To improve temporal resolution the frequency-locked mode of operation was developed, with an in-situ referencing scheme to compensate for signal fluctuations arising from density variations in the probe volume. Spectroscopic grade (i.e. continuously tunable, single-mode) laser sources with high power (greater than 100 mW) are not commercially available at the wavelength of interest (780 nm). We developed an all-solid-state system with a low power (approximately 10 mW) spectroscopic grade laser source in a Littrow cavity is amplified by a broad-area diode laser. We have demonstrated that the slaved output tracks the injected input but have not yet demonstrated power gain by the end of the grant period.

  19. ARBITRARY INTERACTION OF PLANE SUPERSONIC FLOWS

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-11-01

    Full Text Available Subject of study.We consider the Riemann problem for parameters at collision of two plane flows at a certain angle. The problem is solved in the exact statement. Most cases of interference, both stationary and non-stationary gas-dynamic discontinuities, followed by supersonic flows can be reduced to the problem of random interaction of two supersonic flows. Depending on the ratio of the parameters in the flows, outgoing discontinuities turn out to be shock waves, or rarefactionwaves. In some cases, there is no solution at all. It is important to know how to find the domain of existence for the relevant decisions, as the type of shock-wave structures in these domains is known in advance. The Riemann problem is used in numerical methods such as the method of Godunov. As a rule, approximate solution is used, known as the Osher solution, but for a number of problems with a high precision required, solution of this problem needs to be in the exact statement. Main results.Domains of existence for solutions with different types of shock-wave structure have been considered. Boundaries of existence for solutions with two outgoing shock waves are analytically defined, as well as with the outgoing shock wave and rarefaction wave. We identify the area of Mach numbers and angles at which the flows interact and there is no solution. Specific flows with two outgoing rarefaction waves are not considered. Practical significance. The results supplement interference theory of stationary gas-dynamic discontinuities and can be used to develop new methods of numerical calculation with extraction of discontinuities.

  20. Oblique-Flying-Wing Supersonic Transport Airplane

    Science.gov (United States)

    Van Der Velden, Alexander J. M.

    1992-01-01

    Oblique-flying-wing supersonic airplane proposed as possible alternative to B747B (or equivalent). Tranports passengers and cargo as fast as twice speed of sound at same cost as current subsonic transports. Flies at same holding speeds as present supersonic transports but requires only half takeoff distance.

  1. Supersonic Combustion of Hydrogen Jets System in Hypersonic Stream

    International Nuclear Information System (INIS)

    Zhapbasbaev, U.K.; Makashev, E.P.

    2003-01-01

    The data of calculated theoretical investigations of diffusive combustion of plane supersonic hydrogen jets in hypersonic stream received with Navier-Stokes parabola equations closed by one-para metrical (k-l) model of turbulence and multiply staged mechanism of hydrogen oxidation are given. Combustion mechanisms depending on the operating parameters are discussing. The influences of air stream composition and ways off fuel feed to the length of ignition delay and level quantity of hydrogen bum-out have been defined. The calculated theoretical results of investigations permit to make the next conclusions: 1. The diffusive combustion of the system of plane supersonic hydrogen jets in hypersonic flow happens in the cellular structures with alternation zones of intensive running of chemical reactions with their inhibition zones. 2. Gas dynamic and heat Mach waves cause a large - scale viscous formation intensifying mixing of fuel with oxidizer. 3. The system ignition of plane supersonic hydrogen jets in hypersonic airy co-flow happens with the formation of normal flame front of hydrogen airy mixture with transition to the diffusive combustion. 4. The presence of active particles in the flow composition initiates the ignition of hydrogen - airy mixture, provides the intensive running of chemical reactions and shortens the length of ignition delay. 5. The supersonic combustion of hydrogel-airy mixture is characterized by two zones: the intensive chemical reactions with an active energy heat release is occurring in the first zone and in the second - a slow hydrogen combustion limited by the mixing of fuel with oxidizer. (author)

  2. Design of flow-field patterns for proton exchange membrane fuel cell application

    International Nuclear Information System (INIS)

    Rosli, M.I.; Wan Ramli Wan Daud; Kamaruzzaman Sopian; Jaafar Sahari

    2006-01-01

    Fuel cells are electrochemical devices that produce electricity at high efficiency without combustion. Fuel cells are emerging as viable candidates as power sources in many applications, including road vehicles, small-scale power stations, and possibly even portable electronics. This paper addresses the design of flow-field patterns for proton exchange membrane fuel cell (PEMFC). The PEMFC is a low-temperature fuel cell, in which a proton conductive polymer membrane is used as the electrolyte. In PEMFC, flow-field pattern is one important thing that effects the performance of PEMFC. This paper present three types of flow-field pattern that will be consider to be testing using CFD analysis and by experimental. The design look detail on to their shape and dimension to get the best pattern in term of more active electrode area compare to electrode area that will be used. Another advantage and disadvantage for these three type of flow-field patterns from literature also compared in this paper

  3. Supersonic wave detection method and supersonic detection device

    International Nuclear Information System (INIS)

    Machida, Koichi; Seto, Takehiro; Ishizaki, Hideaki; Asano, Rin-ichi.

    1996-01-01

    The present invention provides a method of and device for a detection suitable to a channel box which is used while covering a fuel assembly of a BWR type reactor. Namely, a probe for transmitting/receiving supersonic waves scans on the surface of the channel box. A data processing device determines an index showing a selective orientation degree of crystal direction of the channel box based on the signals received by the probe. A judging device compares the determined index with a previously determined allowable range to judge whether the channel box is satisfactory or not based on the result of the comparison. The judgement are on the basis that (1) the bending of the channel box is caused by the difference of elongation of opposed surfaces, (2) the elongation due to irradiation is caused by the selective orientation of crystal direction, and (3) the bending of the channel box can be suppressed within a predetermined range by suppressing the index determined by the measurement of supersonic waves having a correlation with the selective orientation of the crystal direction. As a result, the performance of the channel box capable of enduring high burnup region can be confirmed in a nondestructive manner. (I.S.)

  4. Detonation in supersonic radial outflow

    KAUST Repository

    Kasimov, Aslan R.

    2014-11-07

    We report on the structure and dynamics of gaseous detonation stabilized in a supersonic flow emanating radially from a central source. The steady-state solutions are computed and their range of existence is investigated. Two-dimensional simulations are carried out in order to explore the stability of the steady-state solutions. It is found that both collapsing and expanding two-dimensional cellular detonations exist. The latter can be stabilized by putting several rigid obstacles in the flow downstream of the steady-state sonic locus. The problem of initiation of standing detonation stabilized in the radial flow is also investigated numerically. © 2014 Cambridge University Press.

  5. Interferograms, schlieren, and shadowgraphs constructed from real- and ideal-gas, two- and three-dimensional computed flowfields

    Science.gov (United States)

    Yates, Leslie A.

    1993-01-01

    The construction of interferograms, schlieren, and shadowgraphs from computed flowfield solutions permits one-to-one comparisons of computed and experimental results. A method of constructing these images from both ideal- and real-gas, two and three-dimensional computed flowfields is described. The computational grids can be structured or unstructured, and multiple grids are an option. Constructed images are shown for several types of computed flows including nozzle, wake, and reacting flows; comparisons to experimental images are also shown. In addition, th sensitivity of these images to errors in the flowfield solution is demonstrated, and the constructed images can be used to identify problem areas in the computations.

  6. Flowfield analysis of helicopter rotor in hover and forward flight based on CFD

    Science.gov (United States)

    Zhao, Qinghe; Li, Xiaodong

    2018-05-01

    The helicopter rotor field is simulated in hover and forward flight based on Computational Fluid Dynamics(CFD). In hover case only one rotor is simulated with the periodic boundary condition in the rotational coordinate system and the grid is fixed. In the non-lift forward flight case, the total rotor is simulated in inertia coordinate system and the whole grid moves rigidly. The dual-time implicit scheme is applied to simulate the unsteady flowfield on the movement grids. The k – ω turbulence model is employed in order to capture the effects of turbulence. To verify the solver, the flowfield around the Caradonna-Tung rotor is computed. The comparison shows a good agreement between the numerical results and the experimental data.

  7. Impact of state-specific flowfield modeling on atomic nitrogen radiation

    Science.gov (United States)

    Johnston, Christopher O.; Panesi, Marco

    2018-01-01

    A hypersonic flowfield model that treats electronic levels of the dominant afterbody radiator N as individual species is presented. This model allows electron-ion recombination rate and two-temperature modeling improvements, the latter which are shown to decrease afterbody radiative heating by up to 30%. This decrease is primarily due to the addition of the electron-impact excitation energy-exchange term to the energy equation governing the vibrational-electronic electron temperature. This model also allows the validity of the often applied quasi-steady-state (QSS) approximation to be assessed. The QSS approximation is shown to fail throughout most of the afterbody region for lower electronic states, although this impacts the radiative intensity reaching the surface by less than 15%. By computing the electronic-state populations of N within the flowfield solver, instead of through the QSS approximation in the radiation solver, the coupling of nonlocal radiative transition rates to the species continuity equations becomes feasible. Implementation of this higher-fidelity level of coupling between the flowfield and radiation solvers is shown to increase the afterbody radiation by up to 50% relative to the conventional model.

  8. Supersonic and transonic Mach probe for calibration control in the Trisonic Wind Tunnel

    Directory of Open Access Journals (Sweden)

    Alexandru Marius PANAIT

    2017-12-01

    Full Text Available A supersonic and high speed transonic Pitot Prandtl is described as it can be implemented in the Trisonic Wind Tunnel for calibration and verification of Mach number precision. A new calculation method for arbitrary precision Mach numbers is proposed and explained. The probe is specially designed for the Trisonic wind tunnel and would greatly simplify obtaining a precise Mach calibration in the critical high transonic and low supersonic regimes, where typically wind tunnels exhibit poor performance. The supersonic Pitot Prandtl combined probe is well known in the aerospace industry, however the proposed probe is a derivative of the standard configuration, combining a stout cone-cylinder probe with a supersonic Pitot static port which allows this configuration to validate the Mach number by three methods: conical flow method – using the pressure ports on a cone generatrix, the Schlieren-optical method of shock wave angle photogrammetry and the Rayleigh supersonic Pitot equation, while having an aerodynamic blockage similar to that of a scaled rocket model commonly used in testing. The proposed probe uses an existing cone-cylinder probe forebody and support, adding only an afterbody with a support for a static port.

  9. Numerical Studies of a Supersonic Fluidic Diverter Actuator for Flow Control

    Science.gov (United States)

    Gokoglu, Suleyman A.; Kuczmarski, Maria A.; Culley, Dennis e.; Raghu, Surya

    2010-01-01

    The analysis of the internal flow structure and performance of a specific fluidic diverter actuator, previously studied by time-dependent numerical computations for subsonic flow, is extended to include operation with supersonic actuator exit velocities. The understanding will aid in the development of fluidic diverters with minimum pressure losses and advanced designs of flow control actuators. The self-induced oscillatory behavior of the flow is successfully predicted and the calculated oscillation frequencies with respect to flow rate have excellent agreement with our experimental measurements. The oscillation frequency increases with Mach number, but its dependence on flow rate changes from subsonic to transonic to supersonic regimes. The delay time for the initiation of oscillations depends on the flow rate and the acoustic speed in the gaseous medium for subsonic flow, but is unaffected by the flow rate for supersonic conditions

  10. A computational study of the supersonic coherent jet

    International Nuclear Information System (INIS)

    Jeong, Mi Seon; Kim, Heuy Dong

    2003-01-01

    In steel-making process of iron and steel industry, the purity and quality of steel can be dependent on the amount of CO contained in the molten metal. Recently, the supersonic oxygen jet is being applied to the molten metal in the electric furnace and thus reduces the CO amount through the chemical reactions between the oxygen jet and molten metal, leading to a better quality of steel. In this application, the supersonic oxygen jet is limited in the distance over which the supersonic velocity is maintained. In order to get longer supersonic jet propagation into the molten metal, a supersonic coherent jet is suggested as one of the alternatives which are applicable to the electric furnace system. It has a flame around the conventional supersonic jet and thus the entrainment effect of the surrounding gas into the supersonic jet is reduced, leading to a longer propagation of the supersonic jet. In this regard, gasdynamics mechanism about why the combustion phenomenon surrounding the supersonic jet causes the jet core length to be longer is not yet clarified. The present study investigates the major characteristics of the supersonic coherent jet, compared with the conventional supersonic jet. A computational study is carried out to solve the compressible, axisymmetric Navier-Stokes equations. The computational results of the supersonic coherent jet are compared with the conventional supersonic jets

  11. An Interactive Method of Characteristics Java Applet to Design and Analyze Supersonic Aircraft Nozzles

    Science.gov (United States)

    Benson, Thomas J.

    2014-01-01

    The Method of Characteristics (MOC) is a classic technique for designing supersonic nozzles. An interactive computer program using MOC has been developed to allow engineers to design and analyze supersonic nozzle flow fields. The program calculates the internal flow for many classic designs, such as a supersonic wind tunnel nozzle, an ideal 2D or axisymmetric nozzle, or a variety of plug nozzles. The program also calculates the plume flow produced by the nozzle and the external flow leading to the nozzle exit. The program can be used to assess the interactions between the internal, external and plume flows. By proper design and operation of the nozzle, it may be possible to lessen the strength of the sonic boom produced at the rear of supersonic aircraft. The program can also calculate non-ideal nozzles, such as simple cone flows, to determine flow divergence and nonuniformities at the exit, and its effect on the plume shape. The computer program is written in Java and is provided as free-ware from the NASA Glenn central software server.

  12. Silent and Efficient Supersonic Bi-Directional Flying Wing

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a Phase I study for a novel concept of a supersonic bi-directional (SBiDir) flying wing (FW) that has the potential to revolutionize supersonic flight...

  13. 75 FR 8427 - Civil Supersonic Aircraft Panel Discussion

    Science.gov (United States)

    2010-02-24

    ... entitled, ``State of the Art of Supersonics Aircraft Technology--What has progressed in science since 1973... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Civil Supersonic Aircraft Panel Discussion AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of meeting participation...

  14. A fundamental study of the supersonic microjet

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, M. S.; Kim, H. S.; Kim, H. D. [Andong National Univ., Andong (Korea, Republic of)

    2001-07-01

    Microjet flows are often encountered in many industrial applications of micro-electro-mechanical systems as well as in medical engineering fields such as a transdermal drug delivery system for needle-free injection of drugs into the skin. The Reynolds numbers of such microjets are usually several orders of magnitude below those of larger-scale jets. The supersonic microjet physics with these low Reynolds numbers are not yet understood to date. Computational modeling and simulation can provide an effective predictive capability for the major features of the supersonic microjets. In the present study, computations using the axisymmetic, compressible, Navier-Stokes equations are applied to understand the supersonic microjet flow physics. The pressure ratio of the microjets is changed to obtain both the under-and over-expanded flows at the exit of the micronozzle. Sonic and supersonic microjets are simulated and compared with some experimental results available. Based on computational results; two microjets are discussed in terms of total pressure, jet decay and supersonic core length.

  15. A fundamental study of the supersonic microjet

    International Nuclear Information System (INIS)

    Jeong, M. S.; Kim, H. S.; Kim, H. D.

    2001-01-01

    Microjet flows are often encountered in many industrial applications of micro-electro-mechanical systems as well as in medical engineering fields such as a transdermal drug delivery system for needle-free injection of drugs into the skin. The Reynolds numbers of such microjets are usually several orders of magnitude below those of larger-scale jets. The supersonic microjet physics with these low Reynolds numbers are not yet understood to date. Computational modeling and simulation can provide an effective predictive capability for the major features of the supersonic microjets. In the present study, computations using the axisymmetic, compressible, Navier-Stokes equations are applied to understand the supersonic microjet flow physics. The pressure ratio of the microjets is changed to obtain both the under-and over-expanded flows at the exit of the micronozzle. Sonic and supersonic microjets are simulated and compared with some experimental results available. Based on computational results; two microjets are discussed in terms of total pressure, jet decay and supersonic core length

  16. Transonic and supersonic ground effect aerodynamics

    Science.gov (United States)

    Doig, G.

    2014-08-01

    A review of recent and historical work in the field of transonic and supersonic ground effect aerodynamics has been conducted, focussing on applied research on wings and aircraft, present and future ground transportation, projectiles, rocket sleds and other related bodies which travel in close ground proximity in the compressible regime. Methods for ground testing are described and evaluated, noting that wind tunnel testing is best performed with a symmetry model in the absence of a moving ground; sled or rail testing is ultimately preferable, though considerably more expensive. Findings are reported on shock-related ground influence on aerodynamic forces and moments in and accelerating through the transonic regime - where force reversals and the early onset of local supersonic flow is prevalent - as well as more predictable behaviours in fully supersonic to hypersonic ground effect flows.

  17. An evaluation of supersonic STOVL technology

    Science.gov (United States)

    Kidwell, G. H., Jr.; Lampkin, B. A.

    1983-01-01

    The purpose of this paper is to document the status of supersonic STOVL aircraft technology. The major focus is the presentation of summaries of pertinent aspects of supersonic STOVL technology, such as justification for STOVL aircraft, current designs and their recognized areas of uncertainty, recent research programs, current activities, plans, etc. The remainder of the paper is an evaluation of the performance differential between a current supersonic STOVL design and three production (or near production) fighters, one of them the AV-8B. The results indicate that there is not a large range difference between a STOL aircraft and a STOVL aircraft, and that other aspects of performance, such as field performance or combat maneuverability, may more than make up for this decrement.

  18. Shock Tunnel Studies of the Hypersonic Flowfield around the Hypervelocity Ballistic Models with Aerospikes

    Science.gov (United States)

    Balakalyani, G.; Saravanan, S.; Jagadeesh, G.

    Reduced drag and aerodynamic heating are the two basic design requirements for any hypersonic vehicle [1]. The flowfield around an axisymmetric blunt body is characterized by a bow shockwave standing ahead of its nose. The pressure and temperature behind this shock wave are very high. This increased pressure and temperature are responsible for the high levels of drag and aerodynamic heating over the body. In the past, there have been many investigations on the use of aerospikes as a drag reduction tool. These studies on spiked bodies aim at reducing both the drag and aerodynamic heating by modifying the hypersonic flowfield ahead of the nose of the body [2]. However, most of them used very simple configurations to experimentally study the drag reduction using spikes at hypersonic speeds [3] and therefore very little experimental data is available for a realistic geometric configuration. In the present study, the standard AGARD Hypervelocity Ballistic model 1 is used as the test model. The addition of the spike to the blunt body significantly alters the flowfield ahead of the nose, leading to the formation of a low pressure conical recirculation region, thus causing a reduction in drag and wall heat flux [4]. In the present investigation, aerodynamic drag force is measured over the Hypervelocity Ballistic model-1, with and without spike, at a flow enthalpy of 1.7 MJ/kg. The experiments are carried out at a Mach number of 8 and at zero angle of attack. An internally mountable accelerometer based 3-component force balance system is used to measure the aerodynamic forces on the model. Also computational studies are carried out to complement the experiments.

  19. Robust Navier-Stokes method for predicting unsteady flowfield and aerodynamic characteristics of helicopter rotor

    Directory of Open Access Journals (Sweden)

    Qijun ZHAO

    2018-02-01

    Full Text Available A robust unsteady rotor flowfield solver CLORNS code is established to predict the complex unsteady aerodynamic characteristics of rotor flowfield. In order to handle the difficult problem about grid generation around rotor with complex aerodynamic shape in this CFD code, a parameterized grid generated method is established, and the moving-embedded grids are constructed by several proposed universal methods. In this work, the unsteady Reynolds-Averaged Navier-Stokes (RANS equations with Spalart-Allmaras are selected as the governing equations to predict the unsteady flowfield of helicopter rotor. The discretization of convective fluxes is accomplished by employing the second-order central difference scheme, third-order MUSCL-Roe scheme, and fifth-order WENO-Roe scheme. Aimed at simulating the unsteady aerodynamic characteristics of helicopter rotor, the dual-time scheme with implicit LU-SGS scheme is employed to accomplish the temporal discretization. In order to improve the computational efficiency of hole-cells and donor elements searching of the moving-embedded grid technology, the “disturbance diffraction method” and “minimum distance scheme of donor elements method” are established in this work. To improve the computational efficiency, Message Passing Interface (MPI parallel method based on subdivision of grid, local preconditioning method and Full Approximation Storage (FAS multi-grid method are combined in this code. By comparison of the numerical results simulated by CLORNS code with test data, it is illustrated that the present code could simulate the aerodynamic loads and aerodynamic noise characteristics of helicopter rotor accurately. Keywords: Aerodynamic characteristics, Helicopter rotor, Moving-embedded grid, Navier-Stokes equations, Upwind schemes

  20. Vortex breakdown in a supersonic jet

    Science.gov (United States)

    Cutler, Andrew D.; Levey, Brian S.

    1991-01-01

    This paper reports a study of a vortex breakdown in a supersonic jet. A supersonic vortical jets were created by tangential injection and acceleration through a convergent-divergent nozzle. Vortex circulation was varied, and the nature of the flow in vortical jets was investigated using several types of flow visualization, including focusing schlieren and imaging of Rayleigh scattering from a laser light sheet. Results show that the vortical jet mixed much more rapidly with the ambient air than a comparable straight jet. When overexpanded, the vortical jet exhibited considerable unsteadiness and showed signs of vortex breakdown.

  1. Supersonic cruise vehicle research/business jet

    Science.gov (United States)

    Kelly, R. J.

    1980-01-01

    A comparison study of a GE-21 variable propulsion system with a Multimode Integrated Propulsion System (MMIPS) was conducted while installed in small M = 2.7 supersonic cruise vehicles with military and business jet possibilities. The 1984 state of the art vehicles were sized to the same transatlantic range, takeoff distance, and sideline noise. The results indicate the MMIPS would result in a heavier vehicle with better subsonic cruise performance. The MMIPS arrangement with one fan engine and two satellite turbojet engines would not be appropriate for a small supersonic business jet because of design integration penalties and lack of redundancy.

  2. Complete analysis of steady and transient missile aerodynamic/propulsive/plume flowfield interactions

    Science.gov (United States)

    York, B. J.; Sinha, N.; Dash, S. M.; Hosangadi, A.; Kenzakowski, D. C.; Lee, R. A.

    1992-07-01

    The analysis of steady and transient aerodynamic/propulsive/plume flowfield interactions utilizing several state-of-the-art computer codes (PARCH, CRAFT, and SCHAFT) is discussed. These codes have been extended to include advanced turbulence models, generalized thermochemistry, and multiphase nonequilibrium capabilities. Several specialized versions of these codes have been developed for specific applications. This paper presents a brief overview of these codes followed by selected cases demonstrating steady and transient analyses of conventional as well as advanced missile systems. Areas requiring upgrades include turbulence modeling in a highly compressible environment and the treatment of particulates in general. Recent progress in these areas are highlighted.

  3. Detection of concrete dam leakage using an integrated geophysical technique based on flow-field fitting method

    Science.gov (United States)

    Dai, Qianwei; Lin, Fangpeng; Wang, Xiaoping; Feng, Deshan; Bayless, Richard C.

    2017-05-01

    An integrated geophysical investigation was performed at S dam located at Dadu basin in China to assess the condition of the dam curtain. The key methodology of the integrated technique used was flow-field fitting method, which allowed identification of the hydraulic connections between the dam foundation and surface water sources (upstream and downstream), and location of the anomalous leakage outlets in the dam foundation. Limitations of the flow-field fitting method were complemented with resistivity logging to identify the internal erosion which had not yet developed into seepage pathways. The results of the flow-field fitting method and resistivity logging were consistent when compared with data provided by seismic tomography, borehole television, water injection test, and rock quality designation.

  4. The Use of Source-Sink and Doublet Distributions Extended to the Solution of Boundary-Value Problems in Supersonic Flow

    Science.gov (United States)

    Heaslet, Max A; Lomax, Harvard

    1948-01-01

    A direct analogy is established between the use of source-sink and doublet distributions in the solution of specific boundary-value problems in subsonic wing theory and the corresponding problems in supersonic theory. The correct concept of the "finite part" of an integral is introduced and used in the calculation of the improper integrals associated with supersonic doublet distributions. The general equations developed are shown to include several previously published results and particular examples are given for the loading on rolling and pitching triangular wings with supersonic leading edges.

  5. Prediction of Mass Flow Rate in Supersonic Natural Gas Processing

    Directory of Open Access Journals (Sweden)

    Wen Chuang

    2015-11-01

    Full Text Available The mass flow rate of natural gas through the supersonic separator was numerically calculated by various cubic equations of state. The numerical results show that the compressibility factor and specific heat ratio for ideal gas law diverge remarkably from real gas models at a high inlet pressure. Simultaneously, the deviation of mass flow calculated by the ideal and real gas models reaches over 10 %. The difference increases with the lower of the inlet temperature regardless of the inlet pressure. A higher back pressure results in an earlier location of the shock wave. The pressure ratio of 0.72 is the first threshold to get the separator work normally. The second threshold is 0.95, in which case the whole flow is subsonic and cannot reach the choked state. The shock position moves upstream with the real gas model compared to the ideal gas law in the cyclonic separation section.

  6. COMMERCIAL SUPERSONIC TRANSPORT PROGRAM. PHASE II-C REPORT. HIGH STRENGTH STEEL EVALUATION FOR SUPERSONIC AIRCRAFT.

    Science.gov (United States)

    JET TRANSPORT AIRCRAFT, *AIRFRAMES, SUPERSONIC AIRCRAFT, STEEL , STRUCTURAL PROPERTIES, FRACTURE(MECHANICS), FATIGUE(MECHANICS), STRESS CORROSION...MICROPHOTOGRAPHY, HIGH TEMPERATURE, NICKEL ALLOYS, COBALT ALLOYS, CARBON, BAINITE , COMMERCIAL AIRCRAFT.

  7. Flow Simulation of Supersonic Inlet with Bypass Annular Duct

    Science.gov (United States)

    Kim, HyoungJin; Kumano, Takayasu; Liou, Meng-Sing; Povinelli, Louis A.; Conners, Timothy R.

    2011-01-01

    A relaxed isentropic compression supersonic inlet is a new concept that produces smaller cowl drag than a conventional inlet, but incurs lower total pressure recovery and increased flow distortion in the (radially) outer flowpath. A supersonic inlet comprising a bypass annulus to the relaxed isentropic compression inlet dumps out airflow of low quality through the bypass duct. A reliable computational fluid dynamics solution can provide considerable useful information to ascertain quantitatively relative merits of the concept, and further provide a basis for optimizing the design. For a fast and reliable performance evaluation of the inlet performance, an equivalent axisymmetric model whose area changes accounts for geometric and physical (blockage) effects resulting from the original complex three-dimensional configuration is proposed. In addition, full three-dimensional calculations are conducted for studying flow phenomena and verifying the validity of the equivalent model. The inlet-engine coupling is carried out by embedding numerical propulsion system simulation engine data into the flow solver for interactive boundary conditions at the engine fan face and exhaust plane. It was found that the blockage resulting from complex three-dimensional geometries in the bypass duct causes significant degradation of inlet performance by pushing the terminal normal shock upstream.

  8. Miniaturized compact water-cooled pitot-pressure probe for flow-field surveys in hypersonic wind tunnels

    Science.gov (United States)

    Ashby, George C.

    1988-01-01

    An experimental investigation of the design of pitot probes for flowfield surveys in hypersonic wind tunnels is reported. The results show that a pitot-pressure probe can be miniaturized for minimum interference effects by locating the transducer in the probe support body and water-cooling it so that the pressure-settling time and transducer temperature are compatible with hypersonic tunnel operation and flow conditions. Flowfield surveys around a two-to-one elliptical cone model in a 20-inch Mach 6 wind tunnel using such a probe show that probe interference effects are essentially eliminated.

  9. A supersonic fan equipped variable cycle engine for a Mach 2.7 supersonic transport

    Science.gov (United States)

    Tavares, T. S.

    1985-01-01

    The concept of a variable cycle turbofan engine with an axially supersonic fan stage as powerplant for a Mach 2.7 supersonic transport was evaluated. Quantitative cycle analysis was used to assess the effects of the fan inlet and blading efficiencies on engine performance. Thrust levels predicted by cycle analysis are shown to match the thrust requirements of a representative aircraft. Fan inlet geometry is discussed and it is shown that a fixed geometry conical spike will provide sufficient airflow throughout the operating regime. The supersonic fan considered consists of a single stage comprising a rotor and stator. The concept is similar in principle to a supersonic compressor, but differs by having a stator which removes swirl from the flow without producing a net rise in static pressure. Operating conditions peculiar to the axially supersonic fan are discussed. Geometry of rotor and stator cascades are presented which utilize a supersonic vortex flow distribution. Results of a 2-D CFD flow analysis of these cascades are presented. A simple estimate of passage losses was made using empirical methods.

  10. Supersonic flaw detection device for nozzle

    International Nuclear Information System (INIS)

    Hata, Moriki.

    1996-01-01

    In a supersonic flaw detection device to be attached to a body surface of a reactor pressure vessel for automatically detecting flaws of a welded portion of a horizontally connected nozzle by using supersonic waves, a running vehicle automatically running along a circumferential direction of the nozzle comprises a supersonic flaw detection means for detecting flaws of the welded portion of the nozzle by using supersonic waves, and an inclination angle sensor for detecting the inclination angle of the running vehicle relative to the central axis of the nozzle. The running distance of the vehicle running along the circumference of the nozzle, namely, the position of the running vehicle from a reference point of the nozzle can be detected accurately by dividing the distance around the nozzle by the inclination angle detected by the inclination angle sensor. Accordingly, disadvantages in the prior art, for example, that the detected values obtained by using an encoder are changed by slipping or idle running of the magnet wheels are eliminated, and accurate flaw detection can be conducted. In addition, an operation of visually adjusting the reference point for the device can be eliminated. An operator's exposure dose can be reduced. (N.H.)

  11. Study of Pressure Oscillations in Supersonic Parachute

    Science.gov (United States)

    Dahal, Nimesh; Fukiba, Katsuyoshi; Mizuta, Kazuki; Maru, Yusuke

    2018-04-01

    Supersonic parachutes are a critical element of planetary mission whose simple structure, light-weight characteristics together with high ratio of aerodynamic drag makes them the most suitable aerodynamic decelerators. The use of parachute in supersonic flow produces complex shock/shock and wake/shock interaction giving rise to dynamic pressure oscillations. The study of supersonic parachute is difficult, because parachute has very flexible structure which makes obtaining experimental pressure data difficult. In this study, a supersonic wind tunnel test using two rigid bodies is done. The wind tunnel test was done at Mach number 3 by varying the distance between the front and rear objects, and the distance of a bundle point which divides suspension lines and a riser. The analysis of Schlieren movies revealed shock wave oscillation which was repetitive and had large pressure variation. The pressure variation differed in each case of change in distance between the front and rear objects, and the change in distance between riser and the rear object. The causes of pressure oscillation are: interaction of wake caused by front object with the shock wave, fundamental harmonic vibration of suspension lines, interference between shock waves, and the boundary layer of suspension lines.

  12. Three-dimensional supersonic vortex breakdown

    Science.gov (United States)

    Kandil, Osama A.; Kandil, Hamdy A.; Liu, C. H.

    1993-01-01

    Three-dimensional supersonic vortex-breakdown problems in bound and unbound domains are solved. The solutions are obtained using the time-accurate integration of the unsteady, compressible, full Navier-Stokes (NS) equations. The computational scheme is an implicit, upwind, flux-difference splitting, finite-volume scheme. Two vortex-breakdown applications are considered in the present paper. The first is for a supersonic swirling jet which is issued from a nozzle into a supersonic uniform flow at a lower Mach number than that of the swirling jet. The second is for a supersonic swirling flow in a configured circular duct. In the first application, an extensive study of the effects of grid fineness, shape and grid-point distribution on the vortex breakdown is presented. Four grids are used in this study and they show a substantial dependence of the breakdown bubble and shock wave on the grid used. In the second application, the bubble-type and helix-type vortex breakdown have been captured.

  13. Where is The Dark Matter: The Flow-field From 2MASS

    Science.gov (United States)

    Crook, Aidan; Huchra, J.; Macri, L.; Masters, K.; Jarrett, T.

    2009-01-01

    We present a map of the flow-field constructed from groups of galaxies in the 2MASS Redshift Survey. Previous efforts have suffered because the underlying surveys either did not penetrate to low galactic latitudes or were not sensitive to elliptical galaxies, thereby missing a significant fraction of the mass. The 2MASS Redshift Survey provides a uniform all-sky magnitude-limited sample in the J, H and Ks bands, 97% complete to Ks10°, sensitive to both ellipticals and spirals. We demonstrate how utilizing the properties of galaxy groups leads to improved predictions of peculiar velocities in the nearby Universe, and use dynamical mass estimates to construct a reliable flow-field to 12,000 km/s. We demonstrate its effectiveness in providing distance estimates, and discuss the advantages of this model over earlier work. With independent knowledge of the peculiar velocity of the Local Group, we discuss the implications for the matter density parameter and bias. This work is supported by a Whiteman Fellowship and NSF grant AST-0406906.

  14. Design of a Scaled Model for Experimental Flowfield Studies of Louvered Plate Fins.

    Science.gov (United States)

    Springer, Marlow E.; Thole, Karen A.

    1997-11-01

    The optimization of compact heat exchangers maximizing heat transfer while minimizing pressure drop is important for many industrial applications. Because the dominant thermal resistance for most air-and-water or air-and-oil heat exchangers occurs on the air side, an understanding of the flowfield on the air side is needed to further optimize the heat exchanger. Louvered plate fin heat exchangers are used not only to increase the convective heat transfer surface area, but also to initiate the growth of multiple boundary layers. There is also evidence that vortex shedding occurs from the trailing edge of the louvers, which would increase heat transfer. Computational fluid dynamics models have been used to design a scaled up model of a louvered plate fin geometry representative of what would occur in a compact heat exchanger. The current model has a louver angle of 27^circ and a louver-to-fin pitch ratio of 1.31. The same technique can be used to design models for other geometries. Critical issues in the design include endwall spacings to maintain a straight inlet flow, and the required number of louver rows to capture the periodic nature of a heat exchanger with perhaps hundreds of rows. Within the louver passages, measurements of mean and time-resolved velocities to characterize the mean flowfield and vortex shedding have been obtained using laser Doppler velocimetry.

  15. Characteristics of pulsed plasma synthetic jet and its control effect on supersonic flow

    Directory of Open Access Journals (Sweden)

    Di Jin

    2015-02-01

    Full Text Available The plasma synthetic jet is a novel flow control approach which is currently being studied. In this paper its characteristic and control effect on supersonic flow is investigated both experimentally and numerically. In the experiment, the formation of plasma synthetic jet and its propagation velocity in quiescent air are recorded and calculated with time resolved schlieren method. The jet velocity is up to 100 m/s and no remarkable difference has been found after changing discharge parameters. When applied in Mach 2 supersonic flow, an obvious shockwave can be observed. In the modeling of electrical heating, the arc domain is not defined as an initial condition with fixed temperature or pressure, but a source term with time-varying input power density, which is expected to better describe the influence of heating process. Velocity variation with different heating efficiencies is presented and discussed and a peak velocity of 850 m/s is achieved in still air with heating power density of 5.0 × 1012 W/m3. For more details on the interaction between plasma synthetic jet and supersonic flow, the plasma synthetic jet induced shockwave and the disturbances in the boundary layer are numerically researched. All the results have demonstrated the control authority of plasma synthetic jet onto supersonic flow.

  16. Method of Characteristic (MOC) Nozzle Flowfield Solver - User’s Guide and Input Manual Version 2.0

    Science.gov (United States)

    2018-01-01

    TECHNICAL REPORT RDMR-SS-17-13 METHOD OF CHARACTERISTIC (MOC) NOZZLE FLOWFIELD SOLVER—USER’S GUIDE AND INPUT MANUAL VERSION 2.0 Kevin D. Kennedy...1 II. PROGRAM READS AND WRITES ...2 B. Program Reads .................................................................................................. 4 C. Program Writes

  17. Modelling and simulation of the compressible turbulence in supersonic shear flows

    International Nuclear Information System (INIS)

    Guezengar, Dominique

    1997-02-01

    This research thesis addresses the modelling of some specific physical problems of fluid mechanics: compressibility (issue of mixing layers), large variations of volumetric mass (boundary layers), and anisotropy (compression ramps). After a presentation of the chosen physical modelling and numerical approximation, the author pays attention to flows at the vicinity of a wall, and to boundary conditions. The next part addresses existing compressibility models and their application to the calculation of supersonic mixing layers. A critical assessment is also performed through calculations of boundary layers and of compression ramps. The next part addresses problems related to large variations of volumetric mass which are not taken by compressibility models into account. A modification is thus proposed for the diffusion term, and is tested for the case of supersonic boundary layers and of mixing layers with high density rates. Finally, anisotropy effects are addressed through the implementation of Explicit Algebraic Stress k-omega Turbulence models (EARSM), and their tests on previously studied cases [fr

  18. Radiative forcing from particle emissions by future supersonic aircraft

    Directory of Open Access Journals (Sweden)

    G. Pitari

    2008-07-01

    Full Text Available In this work we focus on the direct radiative forcing (RF of black carbon (BC and sulphuric acid particles emitted by future supersonic aircraft, as well as on the ozone RF due to changes produced by emissions of both gas species (NOx, H2O and aerosol particles capable of affecting stratospheric ozone chemistry. Heterogeneous chemical reactions on the surface of sulphuric acid stratospheric particles (SSA-SAD are the main link between ozone chemistry and supersonic aircraft emissions of sulphur precursors (SO2 and particles (H2O–H2SO4. Photochemical O3 changes are compared from four independent 3-D atmosphere-chemistry models (ACMs, using as input the perturbation of SSA-SAD calculated in the University of L'Aquila model, which includes on-line a microphysics code for aerosol formation and growth. The ACMs in this study use aircraft emission scenarios for the year 2050 developed by AIRBUS as a part of the EU project SCENIC, assessing options for fleet size, engine technology (NOx emission index, Mach number, range and cruising altitude. From our baseline modeling simulation, the impact of supersonic aircraft on sulphuric acid aerosol and BC mass burdens is 53 and 1.5 μg/m2, respectively, with a direct RF of −11.4 and 4.6 mW/m2 (net RF=−6.8 mW/m2. This paper discusses the similarities and differences amongst the participating models in terms of changes to O3 precursors due to aircraft emissions (NOx, HOx,Clx,Brx and the stratospheric ozone sensitivity to them. In the baseline case, the calculated global ozone change is −0.4 ±0.3 DU, with a net radiative forcing (IR+UV of −2.5± 2 mW/m2. The fraction of this O3-RF attributable to SSA-SAD changes is, however, highly variable among the models, depending on the NOx removal

  19. Advanced Optical Diagnostic Methods for Describing Fuel Injection and Combustion Flowfield Phenomena

    Science.gov (United States)

    Locke, Randy J.; Hicks, Yolanda R.; Anderson, Robert C.

    2004-01-01

    Over the past decade advanced optical diagnostic techniques have evolved and matured to a point where they are now widely applied in the interrogation of high pressure combusting flows. At NASA Glenn Research Center (GRC), imaging techniques have been used successfully in on-going work to develop the next generation of commercial aircraft gas turbine combustors. This work has centered on providing a means by which researchers and designers can obtain direct visual observation and measurements of the fuel injection/mixing/combustion processes and combustor flowfield in two- and three-dimensional views at actual operational conditions. Obtaining a thorough understanding of the chemical and physical processes at the extreme operating conditions of the next generation of combustors is critical to reducing emissions and increasing fuel efficiency. To accomplish this and other tasks, the diagnostic team at GRC has designed and constructed optically accessible, high pressurer high temperature flame tubes and sectar rigs capable of optically probing the 20-60 atm flowfields of these aero-combustors. Among the techniques employed at GRC are planar laser-induced fluorescence (PLIF) for imaging molecular species as well as liquid and gaseous fuel; planar light scattering (PLS) for imaging fuel sprays and droplets; and spontaneous Raman scattering for species and temperature measurement. Using these techniques, optical measurements never before possible have been made in the actual environments of liquid fueled gas turbines. 2-D mapping of such parameters as species (e.g. OH-, NO and kerosene-based jet fuel) distribution, injector spray angle, and fuel/air distribution are just some of the measurements that are now routinely made. Optical imaging has also provided prompt feedback to researchers regarding the effects of changes in the fuel injector configuration on both combustor performance and flowfield character. Several injector design modifications and improvements have

  20. Field of infrasound wave on the earth from blast wave, produced by supersonic flight of a rocket

    International Nuclear Information System (INIS)

    Drobzheva, Ya.V.; Krasnov, V.M.

    2006-01-01

    It was developed a physical model, which allowed calculating a field of infrasound wave on the earth from blast wave, produced by supersonic flight of a rocket. For space launching site Baikonur it is shown that the nearest horizontal distance from launching site of rocket up to which arrive infrasound waves, produced by supersonic flight of a rocket, is 56 km. Amplitude of acoustic impulse decreases in 5 times on distance of 600 km. Duration of acoustic impulse increases from 1.5 to 3 s on the same distance. Values of acoustic field parameters on the earth surface, practically, do not depend from season of launching of rocket. (author)

  1. Supersonic expansion of argon into vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Habets, A H.M.

    1977-01-21

    A theoretical description of a free supersonic expansion process is given. Three distinct regions in the expansion are discussed, namely the continuum region, the gradual transition to the collisionless regime, and the free-molecular-flow stage. Important topics are the peaking-factor formalism, the thermal-conduction model, and the virtual-source formalism. The formation of the molecular beam from the expansion and condensation phenomena occurring in the expanding gas are discussed. The molecular beam machine used in the measurements is described and special attention is given to the cryopumps used in the supersonic sources as well as to the time-of-flight analysis of the molecular beam velocity distributions. Finally, the processing of experimental data is discussed, particularly the least-squares determination of best-fit representations of the measurements.

  2. Li/Li2 supersonic nozzle beam

    International Nuclear Information System (INIS)

    Wu, C.Y.R.; Crooks, J.B.; Yang, S.C.; Way, K.R.; Stwalley, W.C.

    1977-01-01

    The characterization of a lithium supersonic nozzle beam was made using spectroscopic techniques. It is found that at a stagnation pressure of 5.3 kPa (40 torr) and a nozzle throat diameter of 0.4 mm the ground state vibrational population of Li 2 can be described by a Boltzmann distribution with T/sub v/ = 195 +- 30 0 K. The rotational temperature is found to be T/sub r/ = 70 +- 20 0 K by band shape analysis. Measurements by quadrupole mass spectrometer indicates that approximately 10 mole per cent Li 2 dimers are formed at an oven body temperature of 1370 0 K n the supersonic nozzle expansion. This measured mole fraction is in good agreement with the existing dimerization theory

  3. Supersonic expansion of argon into vacuum

    International Nuclear Information System (INIS)

    Habets, A.H.M.

    1977-01-01

    A theoretical description of a free supersonic expansion process is given. Three distinct regions in the expansion are discussed, namely the continuum region, the gradual transition to the collisionless regime, and the free-molecular-flow stage. Important topics are the peaking-factor formalism, the thermal-conduction model, and the virtual-source formalism. The formation of the molecular beam from the expansion and condensation phenomena occurring in the expanding gas are discussed. The molecular beam machine used in the measurements is described and special attention is given to the cryopumps used in the supersonic sources as well as to the time-of-flight analysis of the molecular beam velocity distributions. Finally, the processing of experimental data is discussed, particularly the least-squares determination of best-fit representations of the measurements

  4. Achieving swift equilibration of a Brownian particle using flow-fields

    Science.gov (United States)

    Patra, Ayoti; Jarzynski, Christopher

    Can a system be driven to a targeted equilibrium state on a timescale that is much shorter than its natural equilibration time? In a recent experiment, the swift equilibration of an overdamped Brownian particle was achieved by use of an appropriately designed, time-dependent optical trap potential. Motivated by these results, we develop a general theoretical approach for guiding an ensemble of Brownian particles to track the instantaneous equilibrium distribution of a desired potential U (q , t) . In our approach, we use flow-fields associated with the parametric evolution of the targeted equilibrium state to construct an auxiliary potential U (q , t) , such that dynamics under the composite potential U (t) + U (t) achieves the desired evolution. Our results establish a close connection between the swift equilibration of Brownian particles, quantum shortcuts to adiabaticity, and the dissipationless driving of a classical, Hamiltonian system.

  5. Flow Studies of Decelerators at Supersonic Speeds

    Science.gov (United States)

    1959-01-01

    Wind tunnel tests recorded the effect of decelerators on flow at various supersonic speeds. Rigid parachute models were tested for the effects of porosity, shroud length, and number of shrouds. Flexible model parachutes were tested for effects of porosity and conical-shaped canopy. Ribbon dive brakes on a missile-shaped body were tested for effect of tension cable type and ribbon flare type. The final test involved a plastic sphere on riser lines.

  6. Characterization of supersonic radiation diffusion waves

    International Nuclear Information System (INIS)

    Moore, Alastair S.; Guymer, Thomas M.; Morton, John; Williams, Benjamin; Kline, John L.; Bazin, Nicholas; Bentley, Christopher; Allan, Shelly; Brent, Katie; Comley, Andrew J.; Flippo, Kirk; Cowan, Joseph; Taccetti, J. Martin; Mussack-Tamashiro, Katie; Schmidt, Derek W.; Hamilton, Christopher E.; Obrey, Kimberly; Lanier, Nicholas E.; Workman, Jonathan B.; Stevenson, R. Mark

    2015-01-01

    Supersonic and diffusive radiation flow is an important test problem for the radiative transfer models used in radiation-hydrodynamics computer codes owing to solutions being accessible via analytic and numeric methods. We present experimental results with which we compare these solutions by studying supersonic and diffusive flow in the laboratory. We present results of higher-accuracy experiments than previously possible studying radiation flow through up to 7 high-temperature mean free paths of low-density, chlorine-doped polystyrene foam and silicon dioxide aerogel contained by an Au tube. Measurements of the heat front position and absolute measurements of the x-ray emission arrival at the end of the tube are used to test numerical and analytical models. We find excellent absolute agreement with simulations provided that the opacity and the equation of state are adjusted within expected uncertainties; analytical models provide a good phenomenological match to measurements but are not in quantitative agreement due to their limited scope. - Highlights: • The supersonic, diffusion of x-rays through sub-solid density materials is studied. • The data are more diffusive and of higher velocity than any prior work. • Scaled 1D analytic diffusion models reproduce the heat front evolution. • Refined radiation transport approximations are tested in numerical simulations. • Simulations match the data if material properties are adjusted within uncertainties

  7. Trends in Supersonic Separator design development

    Directory of Open Access Journals (Sweden)

    Altam Rami Ali

    2017-01-01

    Full Text Available Supersonic separator is a new technology with applications in hydrocarbon dew pointing and gas dehydration which can be used to condensate and separate water and heavy hydrocarbons from natural gas. Many researchers have studied the design, performance and efficiency, economic viability, and industrial applications of these separators. The purpose of this paper is to succinctly review recent progress in the design and application of supersonic separators and their limitations. This review has found that while several aspects of this study are well studied, considerable gaps within the published literature still exists in the areas such as turndown flexibility which is a critical requirement to cater for variation of mass flow and since almost all the available designs have a fixed geometry and therefore cannot be considered suitable for variable mass flow rate, which is a common situation in actual site. Hence, the focus needs to be more on designing a flexible geometry that can maintain a high separation efficiency regardless of inlet conditions and mass flow variations. This review is focusing only on the design and application of the supersonic separators without going through the experimental facilities, industrial platform, pilot plants as well as theoretical, analytical, and numerical modelling.

  8. Significance of shock structure on supersonic jet mixing noise of axisymmetric nozzles

    Science.gov (United States)

    Kim, Chan M.; Krejsa, Eugene A.; Khavaran, Abbas

    1994-09-01

    One of the key technical elements in NASA's high speed research program is reducing the noise level to meet the federal noise regulation. The dominant noise source is associated with the supersonic jet discharged from the engine exhaust system. Whereas the turbulence mixing is largely responsible for the generation of the jet noise, a broadband shock-associated noise is also generated when the nozzle operates at conditions other than its design. For both mixing and shock noise components, because the source of the noise is embedded in the jet plume, one can expect that jet noise can be predicted from the jet flowfield computation. Mani et al. developed a unified aerodynamic/acoustic prediction scheme by applying an extension of Reichardt's aerodynamic model to compute turbulent shear stresses which are utilized in estimating the strength of the noise source. Although this method produces a fast and practical estimate of the jet noise, a modification by Khavaran et al. has led to an improvement in aerodynamic solution. The most notable feature in this work is that Reichardt's model is replaced with the computational fluid dynamics (CFD) solution of Reynolds-averaged Navier-Stokes equations. The major advantage of this work is that the essential, noise-related flow quantities such as turbulence intensity and shock strength can be better predicted. The predictions were limited to a shock-free design condition and the effect of shock structure on the jet mixing noise was not addressed. The present work is aimed at investigating this issue. Under imperfectly expanded conditions the existence of the shock cell structure and its interaction with the convecting turbulence structure may not only generate a broadband shock-associated noise but also change the turbulence structure, and thus the strength of the mixing noise source. Failure in capturing shock structures properly could lead to incorrect aeroacoustic predictions.

  9. Low Density Supersonic Decelerator (LDSD) Supersonic Flight Dynamics Test (SFDT) Plume Induced Environment Modelling

    Science.gov (United States)

    Mobley, B. L.; Smith, S. D.; Van Norman, J. W.; Muppidi, S.; Clark, I

    2016-01-01

    Provide plume induced heating (radiation & convection) predictions in support of the LDSD thermal design (pre-flight SFDT-1) Predict plume induced aerodynamics in support of flight dynamics, to achieve targeted freestream conditions to test supersonic deceleration technologies (post-flight SFDT-1, pre-flight SFDT-2)

  10. 76 FR 30231 - Civil Supersonic Aircraft Panel Discussion

    Science.gov (United States)

    2011-05-24

    ... awareness of the continuing technological advancements in supersonic aircraft technology aimed at reducing... Wednesday, April 21, 2010, as part of the joint meeting of the 159th Acoustical Society of America and NOISE... advances in supersonic technology, and for the FAA, the National Aeronautics and Space Administration (NASA...

  11. Flow-Field Characteristics of High-Temperature Annular Buoyant Jets and Their Development Laws Influenced by Ventilation System

    OpenAIRE

    Wang, Yi; Huang, Yanqiu; Liu, Jiaping; Wang, Hai; Liu, Qiuhan

    2013-01-01

    The flow-field characteristics of high-temperature annular buoyant jets as well as the development laws influenced by ventilation system were studied using numerical methods to eliminate the pollutants effectively in this paper. The development laws of high-temperature annular buoyant jets were analyzed and compared with previous studies, including radial velocity distribution, axial velocity and temperature decay, reattachment position, cross-section diameter, volumetric flow rate, and veloc...

  12. IPCS implications for future supersonic transport aircraft

    Science.gov (United States)

    Billig, L. O.; Kniat, J.; Schmidt, R. D.

    1976-01-01

    The Integrated Propulsion Control System (IPCS) demonstrates control of an entire supersonic propulsion module - inlet, engine afterburner, and nozzle - with an HDC 601 digital computer. The program encompasses the design, build, qualification, and flight testing of control modes, software, and hardware. The flight test vehicle is an F-111E airplane. The L.H. inlet and engine will be operated under control of a digital computer mounted in the weapons bay. A general description and the current status of the IPCS program are given.

  13. A systematic study of supersonic jet noise.

    Science.gov (United States)

    Louis, J. F.; Letty, R. P.; Patel, J. R.

    1972-01-01

    The acoustic fields for a rectangular and for an axisymmetric nozzle configuration are studied. Both nozzles are designed for identical flow parameters. It is tried to identify the dominant noise mechanisms. The other objective of the study is to establish scaling laws of supersonic jet noise. A shock tunnel is used in the investigations. Measured sound directivity, propagation direction of Mach waves obtained by shadowgraphs, and the slight dependence of the acoustic efficiency on the level of expansion indicate that Mach waves contribute significantly to the noise produced by a rectangular jet.

  14. Advanced supersonic propulsion study, phase 4

    Science.gov (United States)

    Howlett, R. A.

    1977-01-01

    Installation characteristics for a Variable Stream Control Engine (VSCE) were studied for three advanced supersonic airplane designs. Sensitivity of the VSCE concept to change in technology projections was evaluated in terms of impact on overall installed performance. Based on these sensitivity results, critical technology requirements were reviewed, resulting in the reaffirmation of the following requirements: low-noise nozzle system; a high performance, low emissions duct burner and main burner; hot section technology; variable geometry components; and propulsion integration features, including an integrated electronic control system.

  15. Development and application of theoretical models for Rotating Detonation Engine flowfields

    Science.gov (United States)

    Fievisohn, Robert

    As turbine and rocket engine technology matures, performance increases between successive generations of engine development are becoming smaller. One means of accomplishing significant gains in thermodynamic performance and power density is to use detonation-based heat release instead of deflagration. This work is focused on developing and applying theoretical models to aid in the design and understanding of Rotating Detonation Engines (RDEs). In an RDE, a detonation wave travels circumferentially along the bottom of an annular chamber where continuous injection of fresh reactants sustains the detonation wave. RDEs are currently being designed, tested, and studied as a viable option for developing a new generation of turbine and rocket engines that make use of detonation heat release. One of the main challenges in the development of RDEs is to understand the complex flowfield inside the annular chamber. While simplified models are desirable for obtaining timely performance estimates for design analysis, one-dimensional models may not be adequate as they do not provide flow structure information. In this work, a two-dimensional physics-based model is developed, which is capable of modeling the curved oblique shock wave, exit swirl, counter-flow, detonation inclination, and varying pressure along the inflow boundary. This is accomplished by using a combination of shock-expansion theory, Chapman-Jouguet detonation theory, the Method of Characteristics (MOC), and other compressible flow equations to create a shock-fitted numerical algorithm and generate an RDE flowfield. This novel approach provides a numerically efficient model that can provide performance estimates as well as details of the large-scale flow structures in seconds on a personal computer. Results from this model are validated against high-fidelity numerical simulations that may require a high-performance computing framework to provide similar performance estimates. This work provides a designer a new

  16. An Opportunity for Hydrogen Fueled Supersonic Airliners

    Directory of Open Access Journals (Sweden)

    Alex Forbes

    2011-02-01

    Full Text Available This paper takes a new look at the prospects for developing supersonic civil airliners, considering global demographics, climate change issues, fuel prices and technological advances. Dramatic changes have occurred in the demographics, economics, and market intensity of the Eastern Hemisphere since the 1990s. Carbon reduction imperatives provide a major incentive to invest in developing hydrogen-fueled airliners. The “point-to-point” air route architecture has proved viable with long range mid-size airliners. With a cruise Mach number of 1.4, a large number of destinations become viable for overland supersonic flight. A conceptual design process is used to estimate cost per seat mile for a range of hydrocarbon and hydrogen fuel costs. An argument based on the ideal shape for minimal wave drag, estimates the drag penalty from using hydrogen. Viable aircraft geometries are shown to exist, that match the theoretical ideal shape, showing that the drag estimate is achievable. Conservative design arguments and market estimates suggest that hydrogen-fueled airliners can achieve seat-mile costs low enough to open a large worldwide market and justify a viable fleet size.

  17. A new Lagrangian method for real gases at supersonic speed

    Science.gov (United States)

    Loh, C. Y.; Liou, Meng-Sing

    1992-01-01

    With the renewed interest in high speed flights, the real gas effect is of theoretical as well as practical importance. In the past decade, upwind splittings or Godunov-type Riemann solutions have received tremendous attention and as a result significant progress has been made both in the ideal and non-ideal gas. In this paper, we propose a new approach that is formulated using the Lagrangian description, for the calculation of supersonic/hypersonic real gas inviscid flows. This new formulation avoids the grid generation step which is automatically obtained as the solution procedure marches in the 'time-like' direction. As a result, no remapping is required and the accuracy is faithfully maintained in the Lagrangian level. In this paper, we give numerical results for a variety of real gas problems consisting of essential elements in high speed flows, such as shock waves, expansion waves, slip surfaces and their interactions. Finally, calculations for flows in a generic inlet and nozzle are presented.

  18. Ramp injector scale effects on supersonic combustion

    Science.gov (United States)

    Trebs, Adam

    The combustion field downstream of a 10 degree compression ramp injector has been studied experimentally using wall static pressure measurement, OH-PLIF, and 2 kHz intensified video filtered for OH emission at 320 nm. Nominal test section entrance conditions were Mach 2, 131 kPa static pressure, and 756K stagnation temperature. The experiment was equipped with a variable length inlet duct that facilitated varying the boundary layer development length while the injector shock structure in relation to the combustor geometry remained nearly fixed. As the boundary within an engine varies with flight condition and does not scale linearly with the physical scale of the engine, the boundary layer scale relative to mixing structures of the engine becomes relevant to the problem of engine scaling and general engine performance. By varying the boundary layer thickness from 40% of the ramp height to 150% of the ramp height, changes in the combustion flowfield downstream of the injector could be diagnosed. It was found that flame shape changed, the persistence of the vortex cores was reduced, and combustion efficiency rose as the incident boundary layer grew.

  19. Transient simulation of chamber flowfield in a rod-and-tube configuration solid rocket motor

    International Nuclear Information System (INIS)

    Weaver, J.T.; Stowe, R.A.

    2004-01-01

    Currently, DRDC Valcartier of the Canadian Department of National Defence is designing a prototype rod-and-tube configuration solid propellant rocket motor that will propel a hypersonic velocity missile. This configuration will incorporate a very low port-to-throat area ratio, which in turn results in very high velocity propellant gas traveling across burning propellant surfaces, particularly near the nozzle end of the rocket. This causes an augmentation in the propellant burning rate. While numerical and lumped parameter models are available to design and analyze solid propellant rocket motors and nozzles, many of them provide solutions based on the assumption of quasi-steady flow. Due to the high pressure, high velocity and highly transient nature of the flows expected in the motor under design, it is believed that a CFD simulation will better model the time-dependent phenomena that occur during the functioning of a motor of this type. This simulation couples the fluid dynamics and heat transfer of the gas flowfield within the rocket port to the nozzle and the regression rate of the propellant. By incorporating the regression of the propellant surfaces into the model, the information provided by the resulting time-accurate solution will enable a much improved understanding of the flow phenomena within this rod-and-tube grain motor and a better prediction of the internal ballistics of the motor, which in turn will help in the design of both the motor and the nozzle. (author)

  20. Transient simulation of chamber flowfield in a rod-and-tube configuration solid rocket motor

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, J.T. [Carleton Univ., Ottawa, Ontario (Canada)]. E-mail: jrweaver@storm.ca; Stowe, R.A. [Defence R and D Canada - Valcartier, Val-Belair, Quebec (Canada)

    2004-07-01

    Currently, DRDC Valcartier of the Canadian Department of National Defence is designing a prototype rod-and-tube configuration solid propellant rocket motor that will propel a hypersonic velocity missile. This configuration will incorporate a very low port-to-throat area ratio, which in turn results in very high velocity propellant gas traveling across burning propellant surfaces, particularly near the nozzle end of the rocket. This causes an augmentation in the propellant burning rate. While numerical and lumped parameter models are available to design and analyze solid propellant rocket motors and nozzles, many of them provide solutions based on the assumption of quasi-steady flow. Due to the high pressure, high velocity and highly transient nature of the flows expected in the motor under design, it is believed that a CFD simulation will better model the time-dependent phenomena that occur during the functioning of a motor of this type. This simulation couples the fluid dynamics and heat transfer of the gas flowfield within the rocket port to the nozzle and the regression rate of the propellant. By incorporating the regression of the propellant surfaces into the model, the information provided by the resulting time-accurate solution will enable a much improved understanding of the flow phenomena within this rod-and-tube grain motor and a better prediction of the internal ballistics of the motor, which in turn will help in the design of both the motor and the nozzle. (author)

  1. Linear stability analysis of supersonic axisymmetric jets

    Directory of Open Access Journals (Sweden)

    Zhenhua Wan

    2014-01-01

    Full Text Available Stabilities of supersonic jets are examined with different velocities, momentum thicknesses, and core temperatures. Amplification rates of instability waves at inlet are evaluated by linear stability theory (LST. It is found that increased velocity and core temperature would increase amplification rates substantially and such influence varies for different azimuthal wavenumbers. The most unstable modes in thin momentum thickness cases usually have higher frequencies and azimuthal wavenumbers. Mode switching is observed for low azimuthal wavenumbers, but it appears merely in high velocity cases. In addition, the results provided by linear parabolized stability equations show that the mean-flow divergence affects the spatial evolution of instability waves greatly. The most amplified instability waves globally are sometimes found to be different from that given by LST.

  2. Gas turbine engine with supersonic compressor

    Science.gov (United States)

    Roberts, II, William Byron; Lawlor, Shawn P.

    2015-10-20

    A gas turbine engine having a compressor section using blades on a rotor to deliver a gas at supersonic conditions to a stator. The stator includes one or more of aerodynamic ducts that have converging and diverging portions for deceleration of the gas to subsonic conditions and to deliver a high pressure gas to combustors. The aerodynamic ducts include structures for changing the effective contraction ratio to enable starting even when designed for high pressure ratios, and structures for boundary layer control. In an embodiment, aerodynamic ducts are provided having an aspect ratio of two to one (2:1) or more, when viewed in cross-section orthogonal to flow direction at an entrance to the aerodynamic duct.

  3. Numerical study of MHD supersonic flow control

    Science.gov (United States)

    Ryakhovskiy, A. I.; Schmidt, A. A.

    2017-11-01

    Supersonic MHD flow around a blunted body with a constant external magnetic field has been simulated for a number of geometries as well as a range of the flow parameters. Solvers based on Balbas-Tadmor MHD schemes and HLLC-Roe Godunov-type method have been developed within the OpenFOAM framework. The stability of the solution varies depending on the intensity of magnetic interaction The obtained solutions show the potential of MHD flow control and provide insights into for the development of the flow control system. The analysis of the results proves the applicability of numerical schemes, that are being used in the solvers. A number of ways to improve both the mathematical model of the process and the developed solvers are proposed.

  4. 1 Ft. x 1 Ft. Supersonic Wind Tunnel, Bldg. 37

    Data.gov (United States)

    Federal Laboratory Consortium — The 1- by 1-Foot Supersonic Wind Tunnel (1x), located in the Engine Research Building, is one of the most active test facilities at the Glenn Research Center. Used...

  5. Direct Connect Supersonic Combustion Facility (Research Cell 22)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: RC22 is a continuous-flow, direct-connect supersonic-combustion research facility that is capable of simulating flight conditions from Mach 3.0 to Mach...

  6. Numerical Simulation of Hydrogen Air Supersonic Coaxial Jet

    Science.gov (United States)

    Dharavath, Malsur; Manna, Pulinbehari; Chakraborty, Debasis

    2017-10-01

    In the present study, the turbulent structure of coaxial supersonic H2-air jet is explored numerically by solving three dimensional RANS equations along with two equation k-ɛ turbulence model. Grid independence of the solution is demonstrated by estimating the error distribution using Grid Convergence Index. Distributions of flow parameters in different planes are analyzed to explain the mixing and combustion characteristics of high speed coaxial jets. The flow field is seen mostly diffusive in nature and hydrogen diffusion is confined to core region of the jet. Both single step laminar finite rate chemistry and turbulent reacting calculation employing EDM combustion model are performed to find the effect of turbulence-chemistry interaction in the flow field. Laminar reaction predicts higher H2 mol fraction compared to turbulent reaction because of lower reaction rate caused by turbulence chemistry interaction. Profiles of major species and temperature match well with experimental data at different axial locations; although, the computed profiles show a narrower shape in the far field region. These results demonstrate that standard two equation class turbulence model with single step kinetics based turbulence chemistry interaction can describe H2-air reaction adequately in high speed flows.

  7. On the shock cell structure and noise of supersonic jets

    Science.gov (United States)

    Tam, C. K. W.; Jackson, J. A.

    1983-01-01

    A linear solution modeling the shock cell structure of an axisymmetric supersonic jet operated at off-design conditions is developed by the method of multiple-scales. The model solution takes into account the gradual spatial change of the mean flow in the downstream direction. Turbulence in the mixing layer of the jet has the tendency of smoothing out the sharp velocity and density gradients induced by the shocks. To simulate this effect, eddy viscosity terms are incorporated in the model. It is known that the interaction between the quasi-periodic shock cells and the downstream propagating large turbulence structures in the mixing layer of the jet is responsible for the generation of broadband shock associated noise. Experimentally, the dominant part of this noise has been found to originate from the part of the jet near the end of the potential core. Calculated shock cell spacing at the end of the jet core according to the present model is used to estimate the peak frequencies of the shock associated noise for a range of observation angles. Very favorable agreement with experimental measurements is found.

  8. Study on the characteristics of the supersonic steam injector

    International Nuclear Information System (INIS)

    Abe, Yutaka; Shibayama, Shunsuke

    2014-01-01

    Steam injector is a passive jet pump which operates without power source or rotating machinery and it has high heat transfer performance due to the direct-contact condensation of supersonic steam flow onto subcooled water jet. It has been considered to be applied to the passive safety system for the next-generation nuclear power plants. The objective of the present study is to clarify operating mechanisms of the steam injector and to determine the operating ranges. In this study, temperature and velocity distribution in the mixing nozzle as well as flow directional pressure distribution were measured. In addition, flow structure in whole of the injector was observed with high-speed video camera. It was confirmed that there were unsteady interfacial behavior in mixing nozzle which enhanced heat transfer between steam flow and water jet with calculation of heat transfer coefficient. Discharge pressure at diffuser was also estimated with a one-dimensional model proposed previously. Furthermore, it was clarified that steam flow did not condense completely in mixing nozzle and it was two-phase flow in throat and diffuser, which seemed to induce shock wave. From those results, several discussions and suggestions to develop a physical model which predicts the steam injectors operating characteristics are described in this paper

  9. Numerical simulation of gap effect in supersonic flows

    Directory of Open Access Journals (Sweden)

    Song Mo

    2014-01-01

    Full Text Available The gap effect is a key factor in the design of the heat sealing in supersonic vehicles subjected to an aerodynamic heat load. Built on S-A turbulence model and Roe discrete format, the aerodynamic environment around a gap on the surface of a supersonic aircraft was simulated by the finite volume method. As the presented results indicate, the gap effect depends not only on the attack angle, but also on the Mach number.

  10. Growing quasi-modes in dynamics of supersonic collapse

    International Nuclear Information System (INIS)

    Malkin, V.M.; Khudik, V.N.

    1989-01-01

    The hypothesis of globally stable self-similar regimes existence for supersonic Langmuir collapse plays a significant role in the attempts to construct a theory of strong Langmuir turbulence. A possibility for destruction of the stable against infinitely small perturbations self-similar regime of supersonic collapse by growing quasi-modes is demonstrated via the numerical solution of Cauchi problem for Zakharov equations. The quantitative criterion for the destruction of self-similar regimes is formulated. 9 refs.; 5 figs

  11. Numerical simulation and physical aspects of supersonic vortex breakdown

    Science.gov (United States)

    Liu, C. H.; Kandil, O. A.; Kandil, H. A.

    1993-01-01

    Existing numerical simulations and physical aspects of subsonic and supersonic vortex-breakdown modes are reviewed. The solution to the problem of supersonic vortex breakdown is emphasized in this paper and carried out with the full Navier-Stokes equations for compressible flows. Numerical simulations of vortex-breakdown modes are presented in bounded and unbounded domains. The effects of different types of downstream-exit boundary conditions are studied and discussed.

  12. High Response Dew Point Measurement System for a Supersonic Wind Tunnel

    Science.gov (United States)

    Blumenthal, Philip Z.

    1996-01-01

    A new high response on-line measurement system has been developed to continuously display and record the air stream dew point in the NASA Lewis 10 x 10 supersonic wind tunnel. Previous instruments suffered from such problems as very slow response, erratic readings, and high susceptibility to contamination. The system operates over the entire pressure level range of the 10 x 10 SWT, from less than 2 psia to 45 psia, without the need for a vacuum pump to provide sample flow. The system speeds up tunnel testing, provides large savings in tunnel power costs and provides the dew point input for the data-reduction subroutines which calculate test section conditions.

  13. Research on the penetration characteristic of supersonic molecule beam on the HL-1M tokamak

    International Nuclear Information System (INIS)

    Dong Jiafu; Luo Junling; Tang Nianyi; Li Wei; Zhong Yunze; Liu Yi; Fu Binzhong; Yao Lianghua; Feng Baibing; Qin Yunwen

    2002-01-01

    In the HL-1M plasma experiments, two refueling ways, the pellet injection and the gas puffing, are usually used. In recent years, a new refueling method, the supersonic molecular beam (SMB) injection, has been developed. In this paper, the penetration characteristics of SMB has been analyzed and researched. The SMB experiments were analyzed with H α emissivity measurement. The H α emissivity distribution in the plasma was calculated from multi-channel chord emission singles by means of the asymmetry Abel inversion method

  14. Reynolds-Averaged Turbulence Model Assessment for a Highly Back-Pressured Isolator Flowfield

    Science.gov (United States)

    Baurle, Robert A.; Middleton, Troy F.; Wilson, L. G.

    2012-01-01

    The use of computational fluid dynamics in scramjet engine component development is widespread in the existing literature. Unfortunately, the quantification of model-form uncertainties is rarely addressed with anything other than sensitivity studies, requiring that the computational results be intimately tied to and calibrated against existing test data. This practice must be replaced with a formal uncertainty quantification process for computational fluid dynamics to play an expanded role in the system design, development, and flight certification process. Due to ground test facility limitations, this expanded role is believed to be a requirement by some in the test and evaluation community if scramjet engines are to be given serious consideration as a viable propulsion device. An effort has been initiated at the NASA Langley Research Center to validate several turbulence closure models used for Reynolds-averaged simulations of scramjet isolator flows. The turbulence models considered were the Menter BSL, Menter SST, Wilcox 1998, Wilcox 2006, and the Gatski-Speziale explicit algebraic Reynolds stress models. The simulations were carried out using the VULCAN computational fluid dynamics package developed at the NASA Langley Research Center. A procedure to quantify the numerical errors was developed to account for discretization errors in the validation process. This procedure utilized the grid convergence index defined by Roache as a bounding estimate for the numerical error. The validation data was collected from a mechanically back-pressured constant area (1 2 inch) isolator model with an isolator entrance Mach number of 2.5. As expected, the model-form uncertainty was substantial for the shock-dominated, massively separated flowfield within the isolator as evidenced by a 6 duct height variation in shock train length depending on the turbulence model employed. Generally speaking, the turbulence models that did not include an explicit stress limiter more closely

  15. Flow-Field Characteristics of High-Temperature Annular Buoyant Jets and Their Development Laws Influenced by Ventilation System

    Directory of Open Access Journals (Sweden)

    Yi Wang

    2013-01-01

    Full Text Available The flow-field characteristics of high-temperature annular buoyant jets as well as the development laws influenced by ventilation system were studied using numerical methods to eliminate the pollutants effectively in this paper. The development laws of high-temperature annular buoyant jets were analyzed and compared with previous studies, including radial velocity distribution, axial velocity and temperature decay, reattachment position, cross-section diameter, volumetric flow rate, and velocity field characteristics with different pressures at the exhaust hood inlet. The results showed that when the ratio of outer diameter to inner diameter of the annulus was smaller than 5/2, the flow-field characteristics had significant difference compared to circular buoyant jets with the same outer diameter. For similar diameter ratios, reattachment in this paper occurred further downstream in contrast to previous study. Besides, the development laws of volumetric flow rate and cross-section diameter were given with different initial parameters. In addition, through analyzing air distribution characteristics under the coupling effect of high-temperature annular buoyant jets and ventilation system, it could be found that the position where maximum axial velocity occurred was changing gradually when the pressure at the exhaust hood inlet changed from 0 Pa to −5 Pa.

  16. Flow-field characteristics of high-temperature annular buoyant jets and their development laws influenced by ventilation system.

    Science.gov (United States)

    Wang, Yi; Huang, Yanqiu; Liu, Jiaping; Wang, Hai; Liu, Qiuhan

    2013-01-01

    The flow-field characteristics of high-temperature annular buoyant jets as well as the development laws influenced by ventilation system were studied using numerical methods to eliminate the pollutants effectively in this paper. The development laws of high-temperature annular buoyant jets were analyzed and compared with previous studies, including radial velocity distribution, axial velocity and temperature decay, reattachment position, cross-section diameter, volumetric flow rate, and velocity field characteristics with different pressures at the exhaust hood inlet. The results showed that when the ratio of outer diameter to inner diameter of the annulus was smaller than 5/2, the flow-field characteristics had significant difference compared to circular buoyant jets with the same outer diameter. For similar diameter ratios, reattachment in this paper occurred further downstream in contrast to previous study. Besides, the development laws of volumetric flow rate and cross-section diameter were given with different initial parameters. In addition, through analyzing air distribution characteristics under the coupling effect of high-temperature annular buoyant jets and ventilation system, it could be found that the position where maximum axial velocity occurred was changing gradually when the pressure at the exhaust hood inlet changed from 0 Pa to -5 Pa.

  17. Photoelectron spectroscopy of supersonic molecular beams

    International Nuclear Information System (INIS)

    Pollard, J.E.

    1982-05-01

    A new technique for performing high resolution molecular photoelectron spectroscopy is described, beginning with its conceptual development, through the construction of a prototypal apparatus, to the initial applications on a particularly favorable molecular system. The distinguishing features of this technique are: (1) the introduction of the sample in the form of a collimated supersonic molecular beam; and (2) the use of an electrostatic deflection energy analyzer which is carefully optimized in terms of sensitivity and resolution. This combination makes it possible to obtain photoelectron spectra at a new level of detail for many small molecules. Three experiments are described which rely on the capability to perform rotationally-resolved photoelectron spectroscopy on the hydrogen molecule and its isotopes. The first is a measurement of the ionic vibrational and rotational spectroscopic constants and the vibrationally-selected photoionization cross sections. The second is a determination of the photoelectron asymmetry parameter, β, for selected rotational transitions. The third is an investigation of the rotational relaxation in a free jet expansion, using photoelectron spectroscopy as a probe of the rotational state population distributions. In the closing chapter an assessment is made of the successes and limitations of the technique, and an indication is given of areas for further improvement in future spectrometers

  18. Coherent structures in a supersonic complex nozzle

    Science.gov (United States)

    Magstadt, Andrew; Berry, Matthew; Glauser, Mark

    2016-11-01

    The jet flow from a complex supersonic nozzle is studied through experimental measurements. The nozzle's geometry is motivated by future engine designs for high-performance civilian and military aircraft. This rectangular jet has a single plane of symmetry, an additional shear layer (referred to as a wall jet), and an aft deck representative of airframe integration. The core flow operates at a Mach number of Mj , c = 1 . 6 , and the wall jet is choked (Mj , w = 1 . 0). This high Reynolds number jet flow is comprised of intense turbulence levels, an intricate shock structure, shear and boundary layers, and powerful corner vortices. In the present study, stereo PIV measurements are simultaneously sampled with high-speed pressure measurements, which are embedded in the aft deck, and far-field acoustics in the anechoic chamber at Syracuse University. Time-resolved schlieren measurements have indicated the existence of strong flow events at high frequencies, at a Strouhal number of St = 3 . 4 . These appear to result from von Kàrmàn vortex shedding within the nozzle and pervade the entire flow and acoustic domain. Proper orthogonal decomposition is applied on the current data to identify coherent structures in the jet and study the influence of this vortex street. AFOSR Turbulence and Transition Program (Grant No. FA9550-15-1-0435) with program managers Dr. I. Leyva and Dr. R. Ponnappan.

  19. Photoelectron spectroscopy of supersonic molecular beams

    International Nuclear Information System (INIS)

    Pollard, J.E.; Trevor, D.J.; Lee, Y.T.; Shirley, D.A.

    1981-01-01

    A high-resolution photoelectron spectrometer which uses molecular beam sampling is described. Photons from a rare-gas resonance lamp or UV laser are crossed with the beam from a differentially pumped supersonic nozzle source. The resulting photoelectrons are collected by an electrostatic analyzer of a unique design consisting of a 90 0 spherical sector preanalyzer, a system of lenses, and a 180 0 hemispherical deflector. A multichannel detection system based on dual microchannel plates with a resistive anode position encoder provides an increase in counting efficiency by a factor of 12 over the equivalent single channel detector. The apparatus has demonstrated an instrumental resolution of better than 10 meV FWHM, limited largely by the photon source linewidth. A quadrupole mass spectrometer is used to characterize the composition of the molecular beam. Extensive differential pumping is provided to protect the critical surfaces of the analyzer and mass spectrometer from contamination. Because of the near elimination of Doppler and rotational broadenings, the practical resolution is the highest yet obtained in molecular PES

  20. Molecular description of steady supersonic free jets

    Science.gov (United States)

    Montero, S.

    2017-09-01

    A detailed analysis of the non-local thermal equilibrium (n-LTE) problem in the paraxial zone of silence of supersonic free jets is reported. The study is based on a hybrid approach that combines Navier-Stokes equations with a kinetic equation derived from the generalized Boltzmann (Waldmann-Snider) equation. The resulting system is solved for those flow quantities not easily amenable to experimental measure (translational temperature, flow velocity, and entropy) in terms of the quantities that can be measured accurately (distance, number density, population of rotational states, and their gradients). The reported solutions are essentially exact and are formulated in terms of macroscopic quantities, as well as in terms of elementary collision processes. Emphasis is made on the influence of dissipative effects onto the flow (viscous and diabatic) and of the breakdown of thermal equilibrium onto the evolution of entropy and translational temperature. The influence of inelastic collisions onto these effects is analysed in depth. The reported equations are aimed at optimizing the experimental knowledge of the n-LTE problem and its quantitative interpretation in terms of state-to-state rates for inelastic collisions.

  1. High speed diagnostics for characterization of oxygen / hydrogen rocket injector flowfields

    Science.gov (United States)

    Locke, Justin M.

    Temporally-resolved diagnostics are needed to characterize the highly-turbulent flowfields of rocket engine combustors. Two different high speed diagnostic techniques have been applied successfully to study the combustion and mixing characteristics of single-element shear-coaxial injector flowfield in a rocket combustor. Tunable diode laser absorption spectroscopy (TDLAS) is applied to make in-situ measurements with combusting gas-gas propellants, and high speed imaging incorporating backlighting is applied to combusting and non-combusting liquid-gas and gas-gas propellants. Tunable diode laser absorption spectroscopy has been used to make path-integrated temperature and H2O mole fraction measurements in a gaseous oxygen / gaseous hydrogen uni-element rocket chamber with hot background flow. Four mixture conditions were studied at a nominal chamber pressure of 115 psia. Near infrared diode lasers were utilized to target rovibrational transitions of water vapor, which is created through the combustion processes. Both direct absorption spectroscopy and wavelength modulation spectroscopy with second harmonic normalized by first harmonic (1f-normalized WMS-2 f) techniques were applied, with the harmonic detection technique found to yield the best results. Centerline measurements were made at two axial locations, in the near-injector region and far-field region further downstream. Time-resolved measurements of temperature and H2O mole fraction in the rocket chamber are presented. The TDLAS measurements shows clear differences between the near-injector and downstream measurement locations. Mean path-integrated temperatures and H2O mole fractions in the near-injector region are lower than the downstream measurement location. Fluctuations in path-integrated temperature and H2O mole fraction in the downstream location are significantly greater than the near-injector region. This suggests increased turbulence and larger-scale mixing processes are occurring in the downstream

  2. In-flight imaging of transverse gas jets injected into transonic and supersonic crossflows: Design and development. M.S. Thesis, Mar. 1993

    Science.gov (United States)

    Wang, Kon-Sheng Charles

    1994-01-01

    The design and development of an airborne flight-test experiment to study nonreacting gas jets injected transversely into transonic and supersonic crossflows is presented. Free-stream/crossflow Mach numbers range from 0.8 to 2.0. Planar laser-induced fluorescence (PLIF) of an iodine-seeded nitrogen jet is used to visualize the jet flow. Time-dependent images are obtained with a high-speed intensified video camera synchronized to the laser pulse rate. The entire experimental assembly is configured compactly inside a unique flight-test-fixture (FTF) mounted under the fuselage of the F-104G research aircraft, which serves as a 'flying wind tunnel' at NASA Dryden Flight Research Center. The aircraft is flown at predetermined speeds and altitudes to permit a perfectly expanded (or slightly underexpanded) gas jet to form just outside the FTF at each free-stream Mach number. Recorded gas jet images are then digitized to allow analysis of jet trajectory, spreading, and mixing characteristics. Comparisons will be made with analytical and numerical predictions. This study shows the viability of applying highly sophisticated groundbased flow diagnostic techniques to flight-test vehicle platforms that can achieve a wide range of thermo/fluid dynamic conditions. Realistic flow environments, high enthalpies, unconstrained flowfields, and moderate operating costs are also realized, in contrast to traditional wind-tunnel testing.

  3. System design overview of JAXA small supersonic experimental airplane (NEXST-1)

    OpenAIRE

    Takami, Hikaru; 高見 光

    2007-01-01

    The system of JAXA small supersonic experimental airplane (NEXST-1: National EXperimental Supersonic Transport-1) has been briefly explained. Some design problems that the designers have encountered have also been briefly explained.

  4. Adaptive Aft Signature Shaping of a Low-Boom Supersonic Aircraft Using Off-Body Pressures

    Science.gov (United States)

    Ordaz, Irian; Li, Wu

    2012-01-01

    The design and optimization of a low-boom supersonic aircraft using the state-of-the- art o -body aerodynamics and sonic boom analysis has long been a challenging problem. The focus of this paper is to demonstrate an e ective geometry parameterization scheme and a numerical optimization approach for the aft shaping of a low-boom supersonic aircraft using o -body pressure calculations. A gradient-based numerical optimization algorithm that models the objective and constraints as response surface equations is used to drive the aft ground signature toward a ramp shape. The design objective is the minimization of the variation between the ground signature and the target signature subject to several geometric and signature constraints. The target signature is computed by using a least-squares regression of the aft portion of the ground signature. The parameterization and the deformation of the geometry is performed with a NASA in- house shaping tool. The optimization algorithm uses the shaping tool to drive the geometric deformation of a horizontal tail with a parameterization scheme that consists of seven camber design variables and an additional design variable that describes the spanwise location of the midspan section. The demonstration cases show that numerical optimization using the state-of-the-art o -body aerodynamic calculations is not only feasible and repeatable but also allows the exploration of complex design spaces for which a knowledge-based design method becomes less effective.

  5. Linear models for sound from supersonic reacting mixing layers

    Science.gov (United States)

    Chary, P. Shivakanth; Samanta, Arnab

    2016-12-01

    We perform a linearized reduced-order modeling of the aeroacoustic sound sources in supersonic reacting mixing layers to explore their sensitivities to some of the flow parameters in radiating sound. Specifically, we investigate the role of outer modes as the effective flow compressibility is raised, when some of these are expected to dominate over the traditional Kelvin-Helmholtz (K-H) -type central mode. Although the outer modes are known to be of lesser importance in the near-field mixing, how these radiate to the far-field is uncertain, on which we focus. On keeping the flow compressibility fixed, the outer modes are realized via biasing the respective mean densities of the fast (oxidizer) or slow (fuel) side. Here the mean flows are laminar solutions of two-dimensional compressible boundary layers with an imposed composite (turbulent) spreading rate, which we show to significantly alter the growth of instability waves by saturating them earlier, similar to in nonlinear calculations, achieved here via solving the linear parabolized stability equations. As the flow parameters are varied, instability of the slow modes is shown to be more sensitive to heat release, potentially exceeding equivalent central modes, as these modes yield relatively compact sound sources with lesser spreading of the mixing layer, when compared to the corresponding fast modes. In contrast, the radiated sound seems to be relatively unaffected when the mixture equivalence ratio is varied, except for a lean mixture which is shown to yield a pronounced effect on the slow mode radiation by reducing its modal growth.

  6. Numerical simulation of liquid droplet breakup in supersonic flows

    Science.gov (United States)

    Liu, Nan; Wang, Zhenguo; Sun, Mingbo; Wang, Hongbo; Wang, Bing

    2018-04-01

    A five-equation model based on finite-difference frame was utilized to simulate liquid droplet breakup in supersonic flows. To enhance the interface-capturing quality, an anti-diffusion method was introduced as a correction of volume-fraction after each step of calculation to sharpen the interface. The robustness was guaranteed by the hybrid variable reconstruction in which the second-order and high-order method were respectively employed in discontinuous and continuous flow fields. According to the recent classification of droplet breakup regimes, the simulations lay in the shear induced entrainment regime. Comparing to the momentum of the high-speed air flows, surface tension and viscid force were negligible in both two-dimensional and three-dimensional simulations. The inflow conditions were set as Mach 1.2, 1.5 and 1.8 to reach different dynamic pressure with the liquid to gas density ratio being 1000 initially. According to the results of simulations, the breakup process was divided into three stages which were analyzed in details with the consideration of interactions between gas and liquid. The shear between the high-speed gas flow and the liquid droplet was found to be the sources of surface instabilities on windward, while the instabilities on the leeward side were originated by vortices. Movement of the liquid mass center was studied, and the unsteady acceleration was observed. In addition, the characteristic breakup time was around 1.0 based on the criterion of either droplet thickness or liquid volume fraction.

  7. Comparison of Numerical and Experimental Studies for Flow-Field Optimization Based on Under-Rib Convection in Polymer Electrolyte Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Nguyen Duy Vinh

    2016-10-01

    Full Text Available The flow-field design based on under-rib convection plays an important role in enhancing the performance of polymer electrolyte membrane fuel cells (PEMFCs because it ensures the uniform distribution of the reacting gas and the facilitation of water. This research focused on developing suitable configurations of the anode and cathode bipolar plates to enhance the fuel cell performance based on under-rib convection. The work here evaluated the effects of flow-field designs, including a serpentine flow field with sub channel and by pass and a conventional serpentine flow-field on single-cell performance. Both the experiment and computer simulation indicated that the serpentine flow field with sub channel and by pass (SFFSB configuration enables more effective utilization of the electrocatalysts since it improves reactant transformation rate from the channel to the catalyst layer, thereby dramatically improving the fuel cell performance. The simulation and experimental results indicated that the power densities are increased by up to 16.74% and 18.21%, respectively, when applying suitable flow-field configurations to the anode and cathode bipolar plates. The findings in this are the foundation for enhancing efficient PEMFCs based on flow field design.

  8. Online Coupling of Flow-Field Flow Fractionation and Single Particle Inductively Coupled Plasma-Mass Spectrometry: Characterization of Nanoparticle Surface Coating Thickness and Aggregation State

    Science.gov (United States)

    Surface coating thickness and aggregation state have strong influence on the environmental fate, transport, and toxicity of engineered nanomaterials. In this study, flow-field flow fractionation coupled on-line with single particle inductively coupled plasma-mass spectrometry i...

  9. Summary of the First High-Altitude, Supersonic Flight Dynamics Test for the Low-Density Supersonic Decelerator Project

    Science.gov (United States)

    Clark, Ian G.; Adler, Mark; Manning, Rob

    2015-01-01

    NASA's Low-Density Supersonic Decelerator Project is developing and testing the next generation of supersonic aerodynamic decelerators for planetary entry. A key element of that development is the testing of full-scale articles in conditions relevant to their intended use, primarily the tenuous Mars atmosphere. To achieve this testing, the LDSD project developed a test architecture similar to that used by the Viking Project in the early 1970's for the qualification of their supersonic parachute. A large, helium filled scientific balloon is used to hoist a 4.7 m blunt body test vehicle to an altitude of approximately 32 kilometers. The test vehicle is released from the balloon, spun up for gyroscopic stability, and accelerated to over four times the speed of sound and an altitude of 50 kilometers using a large solid rocket motor. Once at those conditions, the vehicle is despun and the test period begins. The first flight of this architecture occurred on June 28th of 2014. Though primarily a shake out flight of the new test system, the flight was also able to achieve an early test of two of the LDSD technologies, a large 6 m diameter Supersonic Inflatable Aerodynamic Decelerator (SIAD) and a large, 30.5 m nominal diameter supersonic parachute. This paper summarizes this first flight.

  10. Dual-Pump CARS Development and Application to Supersonic Combustion

    Science.gov (United States)

    Magnotti, Gaetano; Cutler, Andrew D.

    2012-01-01

    A dual-pump Coherent Anti-Stokes Raman Spectroscopy (CARS) instrument has been developed to obtain simultaneous measurements of temperature and absolute mole fractions of N2, O2 and H2 in supersonic combustion and generate databases for validation and development of CFD codes. Issues that compromised previous attempts, such as beam steering and high irradiance perturbation effects, have been alleviated or avoided. Improvements in instrument precision and accuracy have been achieved. An axis-symmetric supersonic combusting coaxial jet facility has been developed to provide a simple, yet suitable flow to CFD modelers. Approximately one million dual-pump CARS single shots have been collected in the supersonic jet for varying values of flight and exit Mach numbers at several locations. Data have been acquired with a H2 co-flow (combustion case) or a N2 co-flow (mixing case). Results are presented and the effects of the compressibility and of the heat release are discussed.

  11. Flow Visualization in Supersonic Turbulent Boundary Layers.

    Science.gov (United States)

    Smith, Michael Wayne

    This thesis is a collection of novel flow visualizations of two different flat-plate, zero pressure gradient, supersonic, turbulent boundary layers (M = 2.8, Re _theta ~ 82,000, and M = 2.5, Re_ theta ~ 25,000, respectively). The physics of supersonic shear flows has recently drawn increasing attention with the renewed interest in flight at super and hypersonic speeds. This work was driven by the belief that the study of organized, Reynolds -stress producing turbulence structures will lead to improved techniques for the modelling and control of high-speed boundary layers. Although flow-visualization is often thought of as a tool for providing qualitative information about complex flow fields, in this thesis an emphasis is placed on deriving quantitative results from image data whenever possible. Three visualization techniques were applied--'selective cut-off' schlieren, droplet seeding, and Rayleigh scattering. Two experiments employed 'selective cut-off' schlieren. In the first, high-speed movies (40,000 fps) were made of strong density gradient fronts leaning downstream at between 30^circ and 60^ circ and travelling at about 0.9U _infty. In the second experiment, the same fronts were detected with hot-wires and imaged in real time, thus allowing the examination of the density gradient fronts and their associated single-point mass -flux signals. Two experiments employed droplet seeding. In both experiments, the boundary layer was seeded by injecting a stream of acetone through a single point in the wall. The acetone is atomized by the high shear at the wall into a 'fog' of tiny (~3.5mu m) droplets. In the first droplet experiment, the fog was illuminated with copper-vapor laser sheets of various orientations. The copper vapor laser pulses 'froze' the fog motion, revealing a variety of organized turbulence structures, some with characteristic downstream inclinations, others with large-scale roll-up on the scale of delta. In the second droplet experiment, high

  12. Wave induced supersonic rotation in mirrors

    Science.gov (United States)

    Fetterman, Abraham

    2010-11-01

    Wave-particle interactions in ExB supersonically rotating plasmas feature an unusual effect: particles are diffused by waves in both potential energy and kinetic energy [1]. This wave-particle interaction generalizes the alpha channeling effect, in which radio frequency waves are used to remove alpha particles collisionlessly at low energy. In rotating plasmas, the alpha particles may be removed at low energy through the loss cone, and the energy lost may be transferred to the radial electric field. This eliminates the need for electrodes in the mirror throat, which have presented serious technical issues in past rotating plasma devices. A particularly simple way to achieve this effect is to use a high azimuthal mode number perturbation on the magnetic field [2]. In the rotating frame, this perturbation is seen as a wave near the alpha particle cyclotron harmonic, and can break the azimuthal symmetry and magnetic moment conservation without changing the particle's total energy. The particle may exit if it reduces its kinetic energy and becomes more trapped if it gains kinetic energy, leading to a steady state current that maintains the field. Simulations of single particles in rotating mirrors show that a stationary wave can extract enough energy from alpha particles for a reactor to be self-sustaining. Rotation can also be sustained by waves in plasmas without a kinetic energy source. This type of wave has been considered for plasma centrifuges used for isotope separation [3]. [4pt] [1] A. J. Fetterman and N. J. Fisch, Phys Rev Lett 101, 205003 (2008). [0pt] [2] A. J. Fetterman and N. J. Fisch, Phys. Plasmas 17, 042112 (2010). [0pt] [3] A. J. Fetterman and N. J. Fisch, Plasma Sources Sci. Tech. 18, 045003 (2009).

  13. Advanced supersonic technology and its implications for the future

    Science.gov (United States)

    Driver, C.

    1979-01-01

    A brief overview of the NASA Supersonic Cruise Research (SCR) program is presented. The SCR program has identified significant improvements in the areas of aerodynamics, structures, propulsion, noise reduction, takeoff and landing procedures, and advanced configuration concepts. These improvements tend to overcome most of the problems which led to the cancellation of the National SST program. They offer the promise of an advanced SST family of aircraft which are environmentally acceptable, have flexible range-payload capability, and are economically viable. The areas of technology addressed by the SCR program have direct application to advanced military aircraft and to supersonic executive aircraft.

  14. Investigation of supersonic jets shock-wave structure

    Science.gov (United States)

    Zapryagaev, V. I.; Gubanov, D. A.; Kavun, I. N.; Kiselev, N. P.; Kundasev, S. G.; Pivovarov, A. A.

    2017-10-01

    The paper presents an experimental studies overview of the free supersonic jet flow structure Ma = 1.0, Npr = 5, exhausting from a convergent profiled nozzle into a ambient space. Also was observed the jets in the presence of artificial streamwise vortices created by chevrons and microjets located on the nozzle exit. The technique of experimental investigation, schlieren-photographs and schemes of supersonic jets, and Pitot pressure distributions, are presented. A significant effect of vortex generators on the shock-wave structure of the flow is shown.

  15. Erosion of graphite surface exposed to hot supersonic hydrogen gas

    Science.gov (United States)

    Sharma, O. P.

    1972-01-01

    A theoretical model based on laminar boundary layer flow equations was developed to predict the erosion rate of a graphite (AGCarb-101) surface exposed to a hot supersonic stream of hydrogen gas. The supersonic flow in the nozzle outside the boundary layer formed over the surface of the specimen was determined by assuming one-dimensional isentropic conditions. An overall surface reaction rate expression based on experimental studies was used to describe the interaction of hydrogen with graphite. A satisfactory agreement was found between the results of the computation, and the available experimental data. Some shortcomings of the model and further possible improvements are discussed.

  16. Development and Application of PIV in Supersonic flows

    Science.gov (United States)

    Rong, Z.; Liu, H.; Chen, F.

    2011-09-01

    This paper presents PIV measurements obtained in Mach 4.0 flowfields performed in the SJTU Hypersonic wind tunnel (HWT). In order to certificate this technique, PIV experiments were conducted to the empty test section to provide uniform flow data for comparison with analysis data. Dynamical properties of particle tracers were investigated to measure the particle response across an oblique shock wave. The flow over a sharp cone at Ma = 4.0 were tested in comparasion with the CFD and schlieren visualization. It is shown that shock wave angles measured with PIV are in good agreement with theory and schlieren visualization, in addition the overall flow is consistent with the CFD results.

  17. On the Comparison of the Long Penetration Mode (LPM) Supersonic Counterflowing Jet to the Supersonic Screech Jet

    Science.gov (United States)

    Farr, Rebecca A.; Chang, Chau-Lyan; Jones, Jess H.; Dougherty, N. Sam

    2015-01-01

    Classic tonal screech noise created by under-expanded supersonic jets; Long Penetration Mode (LPM) supersonic phenomenon -Under-expanded counter-flowing jet in supersonic free stream -Demonstrated in several wind tunnel tests -Modeled in several computational fluid dynamics (CFD) simulations; Discussion of LPM acoustics feedback and fluid interactions -Analogous to the aero-acoustics interactions seen in screech jets; Lessons Learned: Applying certain methodologies to LPM -Developed and successfully demonstrated in the study of screech jets -Discussion of mechanically induced excitation in fluid oscillators in general; Conclusions -Large body of work done on jet screech, other aero-acoustic phenomenacan have direct application to the study and applications of LPM cold flow jets

  18. Study of Interaction between Supersonic Flow and Rods Surrounded by Porous Cavity

    Institute of Scientific and Technical Information of China (English)

    Minoru YAGA; Kenji YAMAMOTO; Piotr DOERFFER; Kenyu OYAKAWA

    2006-01-01

    In this paper,some preliminary calculations and the experiments were performed to figure out the flow field,in which some rods were normally inserted into the main flow surrounded by a porous cavity.As a result,it is found that the starting shock wave severely interacts with the rods,the bow shock wave,its reflections,and the porous wall,which are numerically well predicted at some conditions.Moreover,inserting the rods makes the pressure on the upper wall in the porous region increase when the main flow in the porous region is completely supersonic.The calculations also suggest that three rods cause the widest suction area.

  19. Probing the Conformational Landscape of Polyether Building Blocks in Supersonic Jets

    Science.gov (United States)

    Bocklitz, Sebastian; Hewett, Daniel M.; Zwier, Timothy S.; Suhm, Martin A.

    2016-06-01

    Polyethylene oxides (Polyethylene glycoles) and their phenoxy-capped analogs represent a prominent class of important polymers that are highly used as precursor molecules in supramolecular reactions. After a detailed study on the simplest representative (1,2-dimethoxyethane) [1], we present results on oligoethylene oxides with increasing chain lengths obtained by spontaneous Raman scattering in a supersonic jet. Through variation of stagnation pressure, carrier gas, nozzle distance and temperature we gain information on the conformational landscape as well as the mutual interconversion of low energy conformers. The obtained results are compared to state-of-the-art quantum chemical calculations. Additionally, we present UV as well as IR-UV and UV-UV double resonance studies on 1-methoxy-2-phenoxyethane in a supersonic jet. These complementary techniques allow for conformationally selective electronic and vibrational spectra in a closely related conformational landscape. [1] S. Bocklitz, M. A. Suhm, Constraining the Conformational Landscape of a Polyether Building Block by Raman Jet Spectroscopy, Z. Phys. Chem. 2015, 229, 1625-1648.

  20. Validation of Supersonic Film Cooling Modeling for Liquid Rocket Engine Applications

    Science.gov (United States)

    Morris, Christopher I.; Ruf, Joseph H.

    2010-01-01

    Topics include: upper stage engine key requirements and design drivers; Calspan "stage 1" results, He slot injection into hypersonic flow (air); test articles for shock generator diagram, slot injector details, and instrumentation positions; test conditions; modeling approach; 2-d grid used for film cooling simulations of test article; heat flux profiles from 2-d flat plate simulations (run #4); heat flux profiles from 2-d backward facing step simulations (run #43); isometric sketch of single coolant nozzle, and x-z grid of half-nozzle domain; comparison of 2-d and 3-d simulations of coolant nozzles (run #45); flowfield properties along coolant nozzle centerline (run #45); comparison of 3-d CFD nozzle flow calculations with experimental data; nozzle exit plane reduced to linear profile for use in 2-d film-cooling simulations (run #45); synthetic Schlieren image of coolant injection region (run #45); axial velocity profiles from 2-d film-cooling simulation (run #45); coolant mass fraction profiles from 2-d film-cooling simulation (run #45); heat flux profiles from 2-d film cooling simulations (run #45); heat flux profiles from 2-d film cooling simulations (runs #47, #45, and #47); 3-d grid used for film cooling simulations of test article; heat flux contours from 3-d film-cooling simulation (run #45); and heat flux profiles from 3-d and 2-d film cooling simulations (runs #44, #46, and #47).

  1. Active aeroelastic flutter analysis and vibration control of supersonic beams using the piezoelectric actuator/sensor pairs

    International Nuclear Information System (INIS)

    Song, Zhi-Guang; Li, Feng-Ming

    2011-01-01

    The active vibration control of all kinds of structures by using the piezoelectric material has been extensively investigated. In this paper, the active aeroelastic flutter characteristics and vibration control of supersonic beams applying the piezoelectric material are studied further. The piezoelectric materials are bonded on the top and bottom surfaces of the beams to act as the actuator and sensor so that the active aeroelastic flutter suppression for the supersonic beams can be conducted. The supersonic piston theory is adopted to evaluate the aerodynamic pressure. Hamilton's principle with the assumed mode method is used to develop the dynamical model of the structural systems. By using the standard eigenvalue methodology, the solutions for the complex eigenvalue problem are obtained. A negative velocity feedback control strategy is used to obtain active damping. The aeroelastic flutter bounds are calculated and the active aeroelastic flutter characteristics are analyzed. The impulse responses of the structural system are obtained by using the Houbolt numerical algorithm to study the active aeroelastic vibration control. The influences of the non-dimensional aerodynamic pressure on the active flutter control are analyzed. From the numerical results it is observed that the aeroelastic flutter characteristics of the supersonic beams can be significantly improved and that the aeroelastic vibration amplitudes can be remarkably reduced, especially at the flutter points, by using the piezoelectric actuator/sensor pairs which can provide an active damping. Within a certain value of the feedback control gain, with the increase of it, the flutter aerodynamic pressure (or flutter velocity) can be increased and the control results are also improved

  2. Commercial Supersonics Technology Project - Status of Airport Noise

    Science.gov (United States)

    Bridges, James

    2016-01-01

    The Commercial Supersonic Technology Project has been developing databases, computational tools, and system models to prepare for a level 1 milestone, the Low Noise Propulsion Tech Challenge, to be delivered Sept 2016. Steps taken to prepare for the final validation test are given, including system analysis, code validation, and risk reduction testing.

  3. Highly Supersonic Ion Pulses in a Collisionless Magnetized Plasma

    DEFF Research Database (Denmark)

    Juul Rasmussen, Jens; Schrittwieser, R.

    1982-01-01

    The initial transient response of a collisionless plasma to a high positive voltage step is investigated. Four different pulses are observed. An electron plasma wave pulse is followed by an ion burst. The latter is overtaken and absorbed by a highly supersonic ion pulse. Thereafter, an ion...

  4. Commercial supersonic flight; the past and the future

    NARCIS (Netherlands)

    Van Moorselaar, M.

    2013-01-01

    Contemporary world is all about going faster than ever before. Various communication technologies allow us to interact and trade almost instantly with the entire world. Computers are faster than ever before. One thing, however, has slowed down, the speed at which we travel. Supersonic travel is no

  5. Conservation of power of the supersonic acoustic intensity

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn

    2014-01-01

    The supersonic intensity is a quantity that represents the net acoustic output that a source couples into the medium; it can be regarded as a spatially low-pass filtered version of the active intensity. This spatial filtering can lead to significant error due to spatial truncation. In this paper,...

  6. Supersonic laser spray of aluminium alloy on a ceramic substrate

    International Nuclear Information System (INIS)

    Riveiro, A.; Lusquinos, F.; Comesana, R.; Quintero, F.; Pou, J.

    2007-01-01

    Applying a ceramic coating onto a metallic substrate to improve its wear resistance or corrosion resistance has attracted the interest of many researchers during decades. However, only few works explore the possibility to apply a metallic layer onto a ceramic material. This work presents a novel technique to coat ceramic materials with metals: the supersonic laser spraying. In this technique a laser beam is focused on the surface of the precursor metal in such a way that the metal is transformed to the liquid state in the beam-metal interaction zone. A supersonic jet expels the molten material and propels it to the surface of the ceramic substrate. In this study, we present the preliminary results obtained using the supersonic laser spray to coat a commercial cordierite ceramic plate with an Al-Cu alloy using a 3.5 kW CO 2 laser and a supersonic jet of Argon. Coatings were characterized by scanning electron microscopy (SEM) and interferometric profilometry

  7. A note on supersonic flow control with nanosecond plasma actuator

    Science.gov (United States)

    Zheng, J. G.; Cui, Y. D.; Li, J.; Khoo, B. C.

    2018-04-01

    A concept study on supersonic flow control using nanosecond pulsed plasma actuator is conducted by means of numerical simulation. The nanosecond plasma discharge is characterized by the generation of a micro-shock wave in ambient air and a residual heat in the discharge volume arising from the rapid heating of near-surface gas by the quick discharge. The residual heat has been found to be essential for the flow separation control over aerodynamic bodies like airfoil and backward-facing step. In this study, novel experiment is designed to utilize the other flow feature from discharge, i.e., instant shock wave, to control supersonic flow through shock-shock interaction. Both bow shock in front of a blunt body and attached shock anchored at the tip of supersonic projectile are manipulated via the discharged-induced shock wave in an appropriate manner. It is observed that drag on the blunt body is reduced appreciably. Meanwhile, a lateral force on sharp-edged projectile is produced, which can steer the body and give it an effective angle of attack. This opens a promising possibility for extending the applicability of this flow control technique in supersonic flow regime.

  8. Advanced supersonic propulsion study. [with emphasis on noise level reduction

    Science.gov (United States)

    Sabatella, J. A. (Editor)

    1974-01-01

    A study was conducted to determine the promising propulsion systems for advanced supersonic transport application, and to identify the critical propulsion technology requirements. It is shown that noise constraints have a major effect on the selection of the various engine types and cycle parameters. Several promising advanced propulsion systems were identified which show the potential of achieving lower levels of sideline jet noise than the first generation supersonic transport systems. The non-afterburning turbojet engine, utilizing a very high level of jet suppression, shows the potential to achieve FAR 36 noise level. The duct-heating turbofan with a low level of jet suppression is the most attractive engine for noise levels from FAR 36 to FAR 36 minus 5 EPNdb, and some series/parallel variable cycle engines show the potential of achieving noise levels down to FAR 36 minus 10 EPNdb with moderate additional penalty. The study also shows that an advanced supersonic commercial transport would benefit appreciably from advanced propulsion technology. The critical propulsion technology needed for a viable supersonic propulsion system, and the required specific propulsion technology programs are outlined.

  9. Interaction of Eu, Th and U with bentonite colloids in presence of humic acid: a flow-field flow fractionation study

    International Nuclear Information System (INIS)

    Bouby, M.; Geckeis, H.; Schaefer, Th.; Mihai, S.; Fanghaenell, Th.

    2005-01-01

    Full text of publication follows: The actinide mobility in the far-field of a repository site can be strongly influenced by the presence of colloidal species. Field migration experiments at the Grimsel Test Site under low ionic strength (I=10 -3 mol/L) and high pH (∼9.6) conditions have demonstrated a considerable clay colloid-mediated actinide(III/IV) migration [1]. However, those studies rendered it necessary to take the kinetics of notably the actinide-colloid interaction and colloid stability into account [2]. In the present study, we examine the stability of bentonite clay colloids in natural Grimsel groundwater and their interaction with Cs(I), Eu(III), Th(IV) and U(VI) (conc. ∼ 10 -8 mol/L). Experiments cover 12 months contact times and are performed under anoxic conditions. Humic acid (Gohy-573) is added after different contact times as a competing ligand and the time dependent metal ion desorption is followed. Dedicated experiments and thermodynamic speciation calculations are performed to estimate the metal ion speciation within the colloid system. As the experimental metal ion speciation (i.e. differentiation of clay-colloid bound, humic colloid bound and dissolved metal ion species) at the given low concentration conditions is hardly possible by spectroscopic methods, we use Asymmetric Flow-Field Flow Fractionation coupled to UV-Vis spectrophotometry and ICP-MS detection. Unexpectedly, it is found that small-sized bentonite colloids ( d -values, Cs and U do not interact significantly with bentonite colloids, while Th and Eu do. Eu desorption from clay colloids by humic acid is delayed significantly upon increasing the clay colloid-Eu contact time up to several months. Nevertheless, estimated equilibrium conditions are attained after 7 months desorption time. However, it appears that significant fractions of clay colloid borne Th(IV) do not desorb in presence of humic acid and equilibrium conditions estimated from calculation and experiments are not

  10. Dual-Pump CARS Development and Application to Supersonic Combustion

    Science.gov (United States)

    Magnotti, Gaetano

    Successful design of hypersonic air-breathing engines requires new computational fluid dynamics (CFD) models for turbulence and turbulence-chemistry interaction in supersonic combustion. Unfortunately, not enough data are available to the modelers to develop and validate their codes, due to difficulties in taking measurements in such a harsh environment. Dual-pump coherent anti-Stokes Raman spectroscopy (CARS) is a non-intrusive, non-linear, laser-based technique that provides temporally and spatially resolved measurements of temperature and absolute mole fractions of N2, O2 and H2 in H2-air flames. A dual-pump CARS instrument has been developed to obtain measurements in supersonic combustion and generate databases for the CFD community. Issues that compromised previous attempts, such as beam steering and high irradiance perturbation effects, have been alleviated or avoided. Improvements in instrument precision and accuracy have been achieved. An axis-symmetric supersonic combusting coaxial jet facility has been developed to provide a simple, yet suitable flow to CFD modelers. The facility provides a central jet of hot "vitiated air" simulating the hot air entering the engine of a hypersonic vehicle flying at Mach numbers between 5 and 7. Three different silicon carbide nozzles, with exit Mach number 1, 1.6 and 2, are used to provide flows with the effects of varying compressibility. H2 co-flow is available in order to generate a supersonic combusting free jet. Dual-pump CARS measurements have been obtained for varying values of flight and exit Mach numbers at several locations. Approximately one million Dual-pump CARS single shots have been collected in the supersonic jet for varying values of flight and exit Mach numbers at several locations. Data have been acquired with a H2 co-flow (combustion case) or a N 2 co-flow (mixing case). Results are presented and the effects of the compressibility and of the heat release are discussed.

  11. Gas chromatography-mass spectrometry with supersonic molecular beams.

    Science.gov (United States)

    Amirav, Aviv; Gordin, Alexander; Poliak, Marina; Fialkov, Alexander B

    2008-02-01

    Gas chromatography-mass spectrometry (GC-MS) with supersonic molecular beams (SMBs) (also named Supersonic GC-MS) is based on GC and MS interface with SMBs and on the electron ionization (EI) of vibrationally cold analytes in the SMBs (cold EI) in a fly-through ion source. This ion source is inherently inert and further characterized by fast response and vacuum background filtration capability. The same ion source offers three modes of ionization including cold EI, classical EI and cluster chemical ionization (CI). Cold EI, as a main mode, provides enhanced molecular ions combined with an effective library sample identification, which is supplemented and complemented by a powerful isotope abundance analysis method and software. The range of low-volatility and thermally labile compounds amenable for analysis is significantly increased owing to the use of the contact-free, fly-through ion source and the ability to lower sample elution temperatures through the use of high column carrier gas flow rates. Effective, fast GC-MS is enabled particularly owing to the possible use of high column flow rates and improved system selectivity in view of the enhancement of the molecular ion. This fast GC-MS with SMB can be further improved via the added selectivity of MS-MS, which by itself benefits from the enhancement of the molecular ion, the most suitable parent ion for MS-MS. Supersonic GC-MS is characterized by low limits of detection (LOD), and its sensitivity is superior to that of standard GC-MS, particularly for samples that are hard for analysis. The GC separation of the Supersonic GC-MS can be improved with pulsed flow modulation (PFM) GC x GC-MS. Electron ionization LC-MS with SMB can also be combined with the Supersonic GC-MS, with fast and easy switching between these two modes of operation. (c) 2008 John Wiley & Sons, Ltd.

  12. New methods for analyzing transport phenomena in supersonic ejectors

    International Nuclear Information System (INIS)

    Lamberts, Olivier; Chatelain, Philippe; Bartosiewicz, Yann

    2017-01-01

    Highlights: • Simulation of a supersonic ejector with the open source software for CFD OpenFOAM. • Validation of the numerical tool based on flow structures obtained by schlieren. • Application of the momentum and energy tube analysis tools to a supersonic ejector. • Extension of this framework to exergy to construct exergy transport tubes. • Quantification of local transfers and losses of exergy within the ejector. - Abstract: This work aims at providing novel insights into the quantification and the location of the transfers and the irreversibilities within supersonic ejectors, and their connection with the entrainment. In this study, we propose two different and complementary approaches. First of all, recent analysis tools based on momentum and energy tubes (Meyers and Meneveau (2013)) are extended to the present compressible flow context and applied to the mean-flow structure of turbulent flow within the ejector. Furthermore, the transport equation for the mean-flow total exergy is derived and exergy transport tubes are proposed as a tool for the investigation of transport phenomena within supersonic ejectors. In addition to this topological approach, an analysis based on classical stream tubes is performed in order to quantitatively investigate transfers between the primary and the secondary streams all along the ejector. Finally, the present work identifies the location of exergy losses and their origins. Throughout this analysis, new local and cumulative parameters related to transfers and irreversibilities are introduced. The proposed methodology sheds light on the complex phenomena at play and may serve as a basis for the analysis of transport phenomena within supersonic ejectors. For the ejector under consideration, although global transfers are more important in on-design conditions, it is shown that the net gain in exergy of the secondary stream is maximum for a value of the back pressure that is close to the critical back pressure, as

  13. Structures and the Hydrogen Bonding Abilities of Estrogens Studied by Supersonic Jet/laser Spectroscopy

    Science.gov (United States)

    Morishima, Fumiya; Inokuchi, Yoshiya; Ebata, Takayuki

    2013-06-01

    Estrone, estradiol, estriol are known as endogenous estrogen which have the same steroidal frame with different substituent, leading to difference of physiological activity upon the formation of hydrogen bond with estrogen receptor. In the present study, structures of estrogens and their hydrated clusters in a supersonic jet have been studied by various laser spectroscopic techniques and density functional theory calculation to study how the difference of substituents affects their hydrogen bonding ability. Infrared spectra in the OH stretching region indicate a formation of intramolecular hydrogen-bond in estriol, which may lead to weaker physiological activity among the three estrogens. We also measured electronic and infrared spectra of 1:1 hydrated clusters of estrogen. The results show a switch of stable hydration site from the phenolic OH group to the five member ring by substituting one more OH group.

  14. Uncertainty Analysis of the NASA Glenn 8x6 Supersonic Wind Tunnel

    Science.gov (United States)

    Stephens, Julia; Hubbard, Erin; Walter, Joel; McElroy, Tyler

    2016-01-01

    This paper presents methods and results of a detailed measurement uncertainty analysis that was performed for the 8- by 6-foot Supersonic Wind Tunnel located at the NASA Glenn Research Center. The statistical methods and engineering judgments used to estimate elemental uncertainties are described. The Monte Carlo method of propagating uncertainty was selected to determine the uncertainty of calculated variables of interest. A detailed description of the Monte Carlo method as applied for this analysis is provided. Detailed uncertainty results for the uncertainty in average free stream Mach number as well as other variables of interest are provided. All results are presented as random (variation in observed values about a true value), systematic (potential offset between observed and true value), and total (random and systematic combined) uncertainty. The largest sources contributing to uncertainty are determined and potential improvement opportunities for the facility are investigated.

  15. Conformational reduction of DOPA in the gas phase studied by laser desorption supersonic jet laser spectroscopy.

    Science.gov (United States)

    Ishiuchi, Shun-ichi; Mitsuda, Haruhiko; Asakawa, Toshiro; Miyazaki, Mitsuhiko; Fujii, Masaaki

    2011-05-07

    The conformational reduction in catecholamine neurotransmitters was studied by resonance enhanced multi photon ionization (REMPI), ultraviolet-ultraviolet (UV-UV) hole burning and infrared (IR) dip spectroscopy with applying a laser desorption supersonic jet technique to DOPA, which is one of the catecholamine neurotransmitters and has one more phenolic OH group than tyrosine. It is concluded that DOPA has a single observable conformer in the gas phase at low temperature. Quantum chemical calculations at several levels with or without the dispersion correction were also carried out to study stable conformations. From the comparison between the computational IR spectra and the experimental ones, the most stable structure was determined. It is strongly suggested that the conformational reduction is caused by electrostatic interactions, such as a dipole-dipole interaction, between the chain and OH groups. This journal is © the Owner Societies 2011

  16. Evaluation of water cooled supersonic temperature and pressure probes for application to 1366 K flows

    Science.gov (United States)

    Lagen, Nicholas; Seiner, John M.

    1990-01-01

    Water cooled supersonic probes are developed to investigate total pressure, static pressure, and total temperature in high-temperature jet plumes and thereby determine the mean flow properties. Two probe concepts, designed for operation at up to 1366 K in a Mach 2 flow, are tested on a water cooled nozzle. The two probe designs - the unsymmetric four-tube cooling configuration and the symmetric annular cooling design - take measurements at 755, 1089, and 1366 K of the three parameters. The cooled total and static pressure readings are found to agree with previous test results with uncooled configurations. The total-temperature probe, however, is affected by the introduction of water coolant, and effect which is explained by the increased heat transfer across the thermocouple-bead surface. Further investigation of the effect of coolant on the temperature probe is proposed to mitigate the effect and calculate more accurate temperatures in jet plumes.

  17. Synthesis of the scientific activity. Resolution of compressible Navier-Stokes equations for steady supersonic and transonic regimes

    International Nuclear Information System (INIS)

    Angrand, F.

    1990-10-01

    In this HDR (Accreditation to Supervise Researches) report, the author gives an overview of his activities in the field of numerical methods, notably in the field of fluid mechanics and aeronautics. He more particularly addresses the resolution of Euler equations of gas dynamics in transonic and supersonic regimes (equations, centered and off-centered flow calculation, case of one-dimensional and non linear systems), the extension of this work to Navier-Stokes equations (equations, grid adaptation), the study of resolution methods and cost optimisation (Runge-Kutta method, implicit schemes, multi-grid approach). He also addresses the case of hypersonic flows behind a base

  18. Supersonic molecular beam electric resonance spectroscopy and van der Waals molecules

    International Nuclear Information System (INIS)

    Luftman, H.S.

    1982-09-01

    A supersonic molecular beam electric resonance (MBER) spectrometer was built to study the radiofrequency spectra of weakly bound gas phase van der Waals molecules. The instrument and its operating characteristics are described in detail. Sample mass spectra of Ar-ClF gas mixtures are also presented as an illustration of the synthesis of van der Waals molecules. The Stark focusing process for linear polar molecules is discussed and computer-simulated using both second order perturbation and variational methods. Experimental refocusing spectra of OCS and ClF are studied and compared with these trajectory calculations. Though quantitative fitting is poor, there are strong qualitative indicators that the central part of a supersonic beam consists of molecules with a significantly greater population in the lowest energy rotational states than generally assumed. Flop in as opposed to flop out resonance signals for OCS are also numerically predicted and observed. The theoretical properties of the MBER spectrum for linear molecules are elaborated upon with special emphasis on line shape considerations. MBER spectra of OCS and ClF under a variety of conditions are presented and discussed in context to these predictions. There is some uncertainty expressed both in our own modeling and in the manner complex MBER spectra have been analyzed in the past. Finally, an electrostatic potential model is used to quantitatively describe the class of van der Waals molecules Ar-MX, where MX is an alkali halide. Energetics and equilibrium geometries are calculated. The validity of using an electrostatic model to predict van der Waals bond properties is critically discussed

  19. Volume Dynamics Propulsion System Modeling for Supersonics Vehicle Research

    Science.gov (United States)

    Kopasakis, George; Connolly, Joseph W.; Paxson, Daniel E.; Ma, Peter

    2010-01-01

    Under the NASA Fundamental Aeronautics Program the Supersonics Project is working to overcome the obstacles to supersonic commercial flight. The proposed vehicles are long slim body aircraft with pronounced aero-servo-elastic modes. These modes can potentially couple with propulsion system dynamics; leading to performance challenges such as aircraft ride quality and stability. Other disturbances upstream of the engine generated from atmospheric wind gusts, angle of attack, and yaw can have similar effects. In addition, for optimal propulsion system performance, normal inlet-engine operations are required to be closer to compressor stall and inlet unstart. To study these phenomena an integrated model is needed that includes both airframe structural dynamics as well as the propulsion system dynamics. This paper covers the propulsion system component volume dynamics modeling of a turbojet engine that will be used for an integrated vehicle Aero-Propulso-Servo-Elastic model and for propulsion efficiency studies.

  20. Supersonic laser-induced jetting of aluminum micro-droplets

    Energy Technology Data Exchange (ETDEWEB)

    Zenou, M. [Racah Institute of Physics and the Harvey M. Kruger Family Center for Nano-science and Nanotechnology, The Hebrew University of Jerusalem, 91904 Jerusalem (Israel); Additive Manufacturing Lab, Orbotech Ltd., P.O. Box 215, 81101 Yavne (Israel); Sa' ar, A. [Racah Institute of Physics and the Harvey M. Kruger Family Center for Nano-science and Nanotechnology, The Hebrew University of Jerusalem, 91904 Jerusalem (Israel); Kotler, Z. [Additive Manufacturing Lab, Orbotech Ltd., P.O. Box 215, 81101 Yavne (Israel)

    2015-05-04

    The droplet velocity and the incubation time of pure aluminum micro-droplets, printed using the method of sub-nanosecond laser induced forward transfer, have been measured indicating the formation of supersonic laser-induced jetting. The incubation time and the droplet velocity were extracted by measuring a transient electrical signal associated with droplet landing on the surface of the acceptor substrate. This technique has been exploited for studying small volume droplets, in the range of 10–100 femto-litters for which supersonic velocities were measured. The results suggest elastic propagation of the droplets across the donor-to-acceptor gap, a nonlinear deposition dynamics on the surface of the acceptor and overall efficient energy transfer from the laser beam to the droplets.

  1. Cosmic ray acceleration in sources of the supersonic turbulence

    International Nuclear Information System (INIS)

    Bykov, A.M.; Toptygin, I.N.

    1981-01-01

    The mechanism of particle acceleration by the supersonic turbulence is studied. The supersonic turbulence is defined as an ensemble of large- and small-scale plasma motions, in which along with the ranges of smooth parameter variation there are randomly distributed shock wave fronts. Particle interaction with the large-scale turbulence is described by the transfer equation which is true at any relation between the Larmor radius and the transport length. The large-scale turbulence can accelerate particles only due to compressibility effects of the medium. The basic theoretical results concerning turbulence properties in compressed media are presented. Concrete physical conditions and the possibility of acceleration of cosmic rays in the interplanetary space, in the vicinity of suppergiant stars of the O and B class with a great loss of mass and strong stellar winds, in supernova remnants, in the interstellar medium and some extragalactic radio sources are considered [ru

  2. Supersonic laser-induced jetting of aluminum micro-droplets

    International Nuclear Information System (INIS)

    Zenou, M.; Sa'ar, A.; Kotler, Z.

    2015-01-01

    The droplet velocity and the incubation time of pure aluminum micro-droplets, printed using the method of sub-nanosecond laser induced forward transfer, have been measured indicating the formation of supersonic laser-induced jetting. The incubation time and the droplet velocity were extracted by measuring a transient electrical signal associated with droplet landing on the surface of the acceptor substrate. This technique has been exploited for studying small volume droplets, in the range of 10–100 femto-litters for which supersonic velocities were measured. The results suggest elastic propagation of the droplets across the donor-to-acceptor gap, a nonlinear deposition dynamics on the surface of the acceptor and overall efficient energy transfer from the laser beam to the droplets

  3. Modeling of Supersonic Combustion Systems for Sustained Hypersonic Flight

    Directory of Open Access Journals (Sweden)

    Stephen M. Neill

    2017-11-01

    Full Text Available Through Computational Fluid Dynamics and validation, an optimal scramjet combustor has been designed based on twin-strut Hydrogen injection to sustain flight at a desired speed of Mach 8. An investigation undertaken into the efficacy of supersonic combustion through various means of injection saw promising results for Hydrogen-based systems, whereby strut-style injectors were selected over transverse injectors based on their pressure recovery performance and combustive efficiency. The final configuration of twin-strut injectors provided robust combustion and a stable region of net thrust (1873 kN in the nozzle. Using fixed combustor inlet parameters and injection equivalence ratio, the finalized injection method advanced to the early stages of two-dimensional (2-D and three-dimensional (3-D scramjet engine integration. The overall investigation provided a feasible supersonic combustion system, such that Mach 8 sustained cruise could be achieved by the aircraft concept in a computational design domain.

  4. Kr-PLIF for scalar imaging in supersonic flows.

    Science.gov (United States)

    Narayanaswamy, V; Burns, R; Clemens, N T

    2011-11-01

    Experiments were performed to explore the use of two-photon planar laser-induced fluorescence (PLIF) of krypton gas for applications of scalar imaging in supersonic flows. Experiments were performed in an underexpanded jet of krypton, which exhibited a wide range of conditions, from subsonic to hypersonic. Excellent signal-to-noise ratios were obtained, showing the technique is suitable for single-shot imaging. The data were used to infer the distribution of gas density and temperature by correcting the fluorescence signal for quenching effects and using isentropic relations. The centerline variation of the density and temperature from the experiments agree very well with those predicted with an empirical correlation and a CFD simulation (FLUENT). Overall, the high signal levels and quantifiable measurements indicate that Kr-PLIF could be an effective scalar marker for use in supersonic and hypersonic flow applications.

  5. Effect of Microjet Injection on Supersonic Jet Noise

    Science.gov (United States)

    Zaman, K. B. M. Q.; Podboy, G. G.

    2010-01-01

    The effect of microjet (jet) injection on the noise from supersonic jets is investigated. Three convergent-divergent (C-D) nozzles and one convergent nozzle, all having the same exit diameters, are used in the study. The jets are injected perpendicular to the primary jet close to the nozzle lip from six equally-spaced ports having a jet-to-primary-jet diameter ratio of 0.0054. Effects in the over-expanded, fully expanded as well as underexpanded flow regimes are explored. Relative to the effect on subsonic jets, larger reductions in the overall sound pressure level (OASPL) are achieved in most supersonic conditions. The largest reductions are typically associated with suppression of screech and transonic tones. For a shock-free, fully expanded case, the OASPL reductions achieved are comparable to that in the subsonic case; the same correlation, found for subsonic jet noise reduction at shallow observation angle, applies.

  6. Development and Testing of a New Family of Supersonic Decelerators

    Science.gov (United States)

    Clark, Ian G.; Adler, Mark; Rivellini, Tommaso P.

    2013-01-01

    The state of the art in Entry, Descent, and Landing systems for Mars applications is largely based on technologies developed in the late 1960's and early 1970's for the Viking Lander program. Although the 2011 Mars Science Laboratory has made advances in EDL technology, these are predominantly in the areas of entry (new thermal protection systems and guided hypersonic flight) and landing (the sky crane architecture). Increases in entry mass, landed mass, and landed altitude beyond MSL capabilities will require advances predominantly in the field of supersonic decelerators. With this in mind, a multi-year program has been initiated to advance three new types of supersonic decelerators that would enable future large-robotic and human-precursor class missions to Mars.

  7. Tests of a thermal acoustic shield with a supersonic jet

    Science.gov (United States)

    Pickup, N.; Mangiarotty, R. A.; Okeefe, J. V.

    1981-10-01

    Fuel economy is a key element in the design of a future supersonic transport (SST). Variable cycle engines are being developed to provide the most economic combination of characteristics for a range of cruise speeds extending from subsonic speeds for overland flights to the supersonic cruise speeds. For one of these engines, the VCE-702, some form of noise suppression is needed for takeoff/sideline thrusts. The considered investigation is primarily concerned with scale model static tests of one particular concept for achieving that reduction, the thermal acoustic shield (TAS), which could also benefit other candidate SST engines. Other noise suppression devices being considered for SST application are the coannular nozzle, an internally ventilated nozzle, and mechanical suppressors. A test description is provided, taking into account the model configurations, the instrumentation, the test jet conditions, and aspects of screech noise control. Attention is given to shield thickness effects, a spectrum analysis, suppression and performance loss, and installed performance.

  8. Temperature in subsonic and supersonic radiation fronts measured at OMEGA

    Science.gov (United States)

    Johns, Heather; Kline, John; Lanier, Nick; Perry, Ted; Fontes, Chris; Fryer, Chris; Brown, Colin; Morton, John

    2017-10-01

    Propagation of heat fronts relevant to astrophysical plasmas is challenging in the supersonic regime. Plasma Te changes affect opacity and equation of state without hydrodynamic change. In the subsonic phase density perturbations form at material interfaces as the plasma responds to radiation pressure of the front. Recent experiments at OMEGA studied this transition in aerogel foams driven by a hohlraum. In COAX, two orthogonal backlighters drive x-ray radiography and K-shell absorption spectroscopy to diagnose the subsonic shape of the front and supersonic Te profiles. Past experiments used absorption spectroscopy in chlorinated foams to measure the heat front; however, Cl dopant is not suitable for higher material temperatures at NIF. COAX has developed use of Sc and Ti dopants to diagnose Te between 60-100eV and 100-180eV. Analysis with PrismSPECT using OPLIB tabular opacity data will evaluate the platform's ability to advance radiation transport in this regime.

  9. Investigation of nozzle contours in the CSIR supersonic wind tunnel

    CSIR Research Space (South Africa)

    Vallabh, Bhavya

    2017-09-01

    Full Text Available Contours in the CSIR Supersonic Wind Tunnel B Vallabha,b and BW Skewsa Received 17 February 2017, in revised form 23 June 2017 and accepted 25 June 2017 R & D Journal of the South African Institution of Mechanical Engineering 2017, 33, 32-41 http... with the Sivells’ nozzle design method and the method of characteristics technique to design the nozzle profiles for the full supersonic Mach number range 𝟏𝟏 ≀ 𝑎𝑎 ≀ 𝟒𝟒.5 of the facility. Automatic computation was used for the profile...

  10. Ethylene tetrafluoroethylene nanofibers prepared by CO2 laser supersonic drawing

    Directory of Open Access Journals (Sweden)

    A. Suzuki

    2013-06-01

    Full Text Available Ethylene tetrafluoroethylene (ETFE nanofibers were prepared by carbon dioxide (CO2 laser irradiation of asspun ETFE fibers with four different melt flow rates (MFRs in a supersonic jet that was generated by blowing air into a vacuum chamber through the fiber injection orifice. The drawability and superstructure of fibers produced by CO2 laser supersonic drawing depend on the laser power, the chamber pressure, the fiber injection speed, and the MFR. Nanofibers obtained using a laser power of 20 W, a chamber pressure of 20 kPa, and an MFR of 308 g•10 min–1 had an average diameter of 0.303 µm and a degree of crystallinity of 54%.

  11. Wave-driven Rotation in Supersonically Rotating Mirrors

    Energy Technology Data Exchange (ETDEWEB)

    A. Fetterman and N.J. Fisch

    2010-02-15

    Supersonic rotation in mirrors may be produced by radio frequency waves. The waves produce coupled diffusion in ion kinetic and potential energy. A population inversion along the diffusion path then produces rotation. Waves may be designed to exploit a natural kinetic energy source or may provide the rotation energy on their own. Centrifugal traps for fusion and isotope separation may benefit from this wave-driven rotation.

  12. Advanced nuclear turbojet powerplant characteristics summary for supersonic aircraft

    International Nuclear Information System (INIS)

    Larson, John W.

    1959-01-01

    The estimated powerplant characteristics of an advanced nuclear powerplant intended for use in a nuclear supersonic manned airplane is contained in this report. This nuclear powerplant consists of a 575 MW, high temperature, lithium-cooled, solid fuel element-type reactor coupled to six turbojet engines especially designed for a supersonic nuclear airplane. The lithium coolant passes from the reactor at 2000F directly to the engine radiators without the use of an intermediate heat exchanger. The engines are fitted with burners enabling the thrust produced by the nuclear powerplant to be augmented by the use of chemical fuel for the take-off, transonic acceleration and landing portions of the flight. The powerplant components have been selected for a maximum thrust-to-weight ratio at Mach 3 and 55,000 feet altitude on nuclear heat only operation compromised for net thrust produced with chemical fuel augmentation during the transonic portion of flight. The power plant data presented, therefore, are primarily applicable to an all supersonic mission on nuclear heat alone. The powerplant data presented in this report are an extension of data contained in PWAC-243, 'NJ-14 All-Nuclear Supersonic Bomber Powerplant Characteristics Summary, March 11, 1958', to a higher reactor power. In addition, the engine compressor pressure ratio has been increased to improve transonic thrust characteristics. Weight data are tabulated for the 575 MW powerplant. The engine envelope based on preliminary radiator size estimates is illustrated. A liquid metal system flow schematic and piping data are included. Shield information including reactor shield outline, assumptions, weights, and direct dose pattern at 50 feet is also included. Estimated performance on nuclear heat only operation and nuclear heat plus burning is presented for an envelope of flight conditions.

  13. Supersonic plasma jet interaction with gases and plasmas

    Czech Academy of Sciences Publication Activity Database

    Nicolai, P.; Stenz, C.; Tikhonchuk, V.; Ribeyre, X.; Kasperczuk, A.; Pisarczyk, T.; Juha, Libor; Krouský, Eduard; Mašek, Karel; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Ullschmied, Jiří; Kálal, M.; Klír, D.; Kravárik, J.; Kubeš, P.; Pisarczyk, P.

    2009-01-01

    Roč. 322, 1-4 (2009), 11-17 ISSN 0004-640X R&D Projects: GA MŠk(CZ) LC528; GA MŠk LA08024 Institutional research plan: CEZ:AV0Z10100523; CEZ:AV0Z20430508 Keywords : supersonic plasma jet * laser experiment * shock Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.404, year: 2009

  14. Visualization of supersonic diesel fuel jets using a shadowgraph technique

    Science.gov (United States)

    Pianthong, Kulachate; Behnia, Masud; Milton, Brian E.

    2001-04-01

    High-speed liquid jets have been widely used to cut or penetrate material. It has been recently conjectured that the characteristics of high-speed fuel jets may also be of benefit to engines requiring direct fuel injection into the combustion chamber. Important factors are combustion efficiency and emission control enhancement for better atomization. Fundamental studies of very high velocity liquid jets are therefore very important. The characteristics and behavior of supersonic liquid jets have been studied with the aid of a shadowgraph technique. The high-speed liquid jet (in the supersonic range) is generated by the use of a vertical, single stage powder gun. The performance of the launcher and its relation to the jet exit velocity, with a range of nozzle shapes, has been examined. This paper presents the visual evidence of supersonic diesel fuel jets (velocity around 2000 m/s) investigated by the shadowgraph method. An Argon jet has been used as a light source. With a rise time of 0.07 microseconds, light duration of 0.2 microseconds and the use of high speed Polaroid film, the shadowgraph method can effectively capture the hypersonic diesel fuel jet and its strong leading edge shock waves. This provides a clearer picture of each stage of the generation of hypersonic diesel fuel jets and makes the study of supersonic diesel fuel jet characteristics and the potential for auto-ignition possible. Also, in the experiment, a pressure relief section has been used to minimize the compressed air or blast wave ahead of the projectile. However, the benefit of using a pressure relief section in the design is not clearly known. To investigate this effect, additional experiments have been performed with the use of the shadowgraph method, showing the projectile leaving and traveling inside the nozzle at a velocity around 1100 m/s.

  15. Wave-driven Rotation in Supersonically Rotating Mirrors

    International Nuclear Information System (INIS)

    Fetterman, A.; Fisch, N.J.

    2010-01-01

    Supersonic rotation in mirrors may be produced by radio frequency waves. The waves produce coupled diffusion in ion kinetic and potential energy. A population inversion along the diffusion path then produces rotation. Waves may be designed to exploit a natural kinetic energy source or may provide the rotation energy on their own. Centrifugal traps for fusion and isotope separation may benefit from this wave-driven rotation.

  16. Equilibrium calculations, ch. 6

    International Nuclear Information System (INIS)

    Deursen, A.P.J. van

    1976-01-01

    A calculation is presented of dimer intensities obtained in supersonic expansions. There are two possible limiting considerations; the dimers observed are already present in the source, in thermodynamic equilibrium, and are accelerated in the expansion. Destruction during acceleration is neglected, as are processes leading to newly formed dimers. On the other hand one can apply a kinetic approach, where formation and destruction processes are followed throughout the expansion. The difficulty of this approach stems from the fact that the density, temperature and rate constants have to be known at all distances from the nozzle. The simple point of view has been adopted and the measured dimer intensities are compared with the equilibrium concentration in the source. The comparison is performed under the assumption that the detection efficiency for dimers is twice the detection efficiency for monomers. The experimental evidence against the simple point of view that the dimers of the onset region are formed in the source already, under equilibrium conditions, is discussed. (Auth.)

  17. THE TURBULENT DYNAMO IN HIGHLY COMPRESSIBLE SUPERSONIC PLASMAS

    Energy Technology Data Exchange (ETDEWEB)

    Federrath, Christoph [Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611 (Australia); Schober, Jennifer [Universität Heidelberg, Zentrum für Astronomie, Institut für Theoretische Astrophysik, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany); Bovino, Stefano; Schleicher, Dominik R. G., E-mail: christoph.federrath@anu.edu.au [Institut für Astrophysik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany)

    2014-12-20

    The turbulent dynamo may explain the origin of cosmic magnetism. While the exponential amplification of magnetic fields has been studied for incompressible gases, little is known about dynamo action in highly compressible, supersonic plasmas, such as the interstellar medium of galaxies and the early universe. Here we perform the first quantitative comparison of theoretical models of the dynamo growth rate and saturation level with three-dimensional magnetohydrodynamical simulations of supersonic turbulence with grid resolutions of up to 1024{sup 3} cells. We obtain numerical convergence and find that dynamo action occurs for both low and high magnetic Prandtl numbers Pm = ν/η = 0.1-10 (the ratio of viscous to magnetic dissipation), which had so far only been seen for Pm ≥ 1 in supersonic turbulence. We measure the critical magnetic Reynolds number, Rm{sub crit}=129{sub −31}{sup +43}, showing that the compressible dynamo is almost as efficient as in incompressible gas. Considering the physical conditions of the present and early universe, we conclude that magnetic fields need to be taken into account during structure formation from the early to the present cosmic ages, because they suppress gas fragmentation and drive powerful jets and outflows, both greatly affecting the initial mass function of stars.

  18. Data Quality Assurance for Supersonic Jet Noise Measurements

    Science.gov (United States)

    Brown, Clifford A.; Henderson, Brenda S.; Bridges, James E.

    2010-01-01

    The noise created by a supersonic aircraft is a primary concern in the design of future high-speed planes. The jet noise reduction technologies required on these aircraft will be developed using scale-models mounted to experimental jet rigs designed to simulate the exhaust gases from a full-scale jet engine. The jet noise data collected in these experiments must accurately predict the noise levels produced by the full-scale hardware in order to be a useful development tool. A methodology has been adopted at the NASA Glenn Research Center s Aero-Acoustic Propulsion Laboratory to insure the quality of the supersonic jet noise data acquired from the facility s High Flow Jet Exit Rig so that it can be used to develop future nozzle technologies that reduce supersonic jet noise. The methodology relies on mitigating extraneous noise sources, examining the impact of measurement location on the acoustic results, and investigating the facility independence of the measurements. The methodology is documented here as a basis for validating future improvements and its limitations are noted so that they do not affect the data analysis. Maintaining a high quality jet noise laboratory is an ongoing process. By carefully examining the data produced and continually following this methodology, data quality can be maintained and improved over time.

  19. Heat, mass and force flows in supersonic shockwave interaction

    Science.gov (United States)

    Dixon, John Michael

    There is no cost effective way to deliver a payload to space and, with rising fuel prices, currently the price to travel commercially is also becoming more prohibitive to the public. During supersonic flight, compressive shock waves form around the craft which could be harnessed to deliver an additional lift on the craft. Using a series of hanging plates below a lifting wing design, the total lift generated can be increased above conventional values, while still maintaining a similar lift-to-drag ratio. Here, we study some of the flows involved in supersonic shockwave interaction. This analysis uses ANSYS Fluent Computational Fluid Dynamics package as the modeler. Our findings conclude an increase of up to 30% lift on the modeled craft while maintaining the lift-to-drag profile of the unmodified lifting wing. The increase in lift when utilizing the shockwave interaction could increase transport weight and reduce fuel cost for space and commercial flight, as well as mitigating negative effects associated with supersonic travel.

  20. A model for supersonic and hypersonic impactors for nanoparticles

    International Nuclear Information System (INIS)

    Abouali, Omid; Ahmadi, Goodarz

    2005-01-01

    In this study the performance of supersonic and hypersonic impactors for collection efficiency of nanoparticles (in the size range of 2-100 nm) under various operating conditions is analyzed. Axisymmetric forms of the compressible Navier-Stokes and energy equations are solved and the airflow and thermal condition in the impactor are evaluated. A Lagrangian particle trajectory analysis procedure is used and the deposition rates of different size particles under various operating conditions are studied. For dilute particle concentrations, the assumption of one-way interaction is used and the effect of particles on gas flow field is ignored. The importance of drag, lift and Brownian forces on particle motions in supersonic impactors is discussed. Sensitivity of the simulation results to the use of different assumptions for the Cunningham correction coefficient is studied. It is shown that accurate evaluation of the gas mean free path and the Cunningham correction factor is important for accurate simulation of nano-particle transport and deposition in supersonic/hypersonic impactors. The computer simulation results are compared favorably with the available experimental data

  1. Hydrogen tube vehicle for supersonic transport: 2. Speed and energy

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Arnold R. [Vehicle Projects Inc and Supersonic Tubevehicle LLC, 200 Violet St, Suite 100, Golden, CO 80401 (United States)

    2010-06-15

    The central concept of a new idea in high-speed transport is that operation of a vehicle in a hydrogen atmosphere, because of the low density of hydrogen, would increase sonic speed by a factor of 3.8 and decrease drag by 15 relative to air. A hydrogen atmosphere requires that the vehicle operate within a hydrogen-filled tube or pipeline, which serves as a phase separator. The supersonic tube vehicle (STV) can be supersonic with respect to air outside the tube while remaining subsonic inside. It breathes hydrogen fuel for its propulsion fuel cells from the tube itself. This paper, second in a series on the scientific foundations of the supersonic tube vehicle, tests the hypothesis that the STV will be simultaneously fast and energy efficient by comparing its predicted speed and energy consumption with that of four long-haul passenger transport modes: road, rail, maglev, and air. The study establishes the speed ranking STV >> airplane > maglev > train > coach (intercity bus) and the normalized energy consumption ranking Airplane >> coach > maglev > train > STV. Consistent with the hypothesis, the concept vehicle is both the fastest and lowest energy consuming mode. In theory, the vehicle can cruise at Mach 2.8 while consuming less than half the energy per passenger of a Boeing 747 at a cruise speed of Mach 0.81. (author)

  2. Mathematical Modeling of Air Flowfield at Urban Environment: the Case of Road Network at the Historical Centre of Kifissia's Municipality

    Science.gov (United States)

    Papakonstantinou, K.; Belias, C.

    2008-09-01

    The present paper refers to the numerical analysis of air flowfield at urban environments and the conducting thermal comfort after the evaluation of the examined space using CFD methods, taking into account bioclimatic principles at the architectural design. More specially, the paper draws attention to the physical procedures governing air movement at an urban environment (a road network) at Kifissia (a Municipality of north Athens), trying to form them in such way that will lead to the thermal comfort of the area's users. The study presents a mathematical model, implemented in a general computer code that can provide detailed information on velocity, prevailing in three-dimensional spaces of any geometrical complexity. Turbulent flow is simulated and buoyancy effects are taken into account. This simulation procedure is intended to contribute to the effort towards designing urban environments, using thermal comfort criteria at the bioclimatic design. A computer model of this kind will provide the architects or the environmental engineers with powerful and economical means of evaluating alternative spaces' designs.

  3. Interferometric analysis of laboratory photoionized plasmas utilizing supersonic gas jet targets.

    Science.gov (United States)

    Swanson, Kyle James; Ivanov, Vladimir; Mancini, Roberto; Mayes, Daniel C.

    2018-06-01

    Photoionized plasmas are an important component of active galactic nuclei, x-ray binary systems and other astrophysical objects. Laboratory produced photoionized plasmas have mainly been studied at large scale facilities, due to the need for high intensity broadband x-ray flux. Using supersonic gas jets as targets has allowed university scale pulsed power generators to begin similar research. The two main advantages of this approach with supersonic gas jets include: possibility of a closer location to the x-ray source and no attenuation related to material used for containment and or tamping. Due to these factors, this experimental platform creates a laboratory environment that more closely resembles astrophysical environments. This system was developed at the Nevada Terawatt Facility using the 1 MA pulsed power generator Zebra. Neon, argon, and nitrogen supersonic gas jets are produced approximately 7-8mm from the z-pinch axis. The high intensity broadband x-ray flux produced by the collapse of the z-pinch wire array implosion irradiates the gas jet. Cylindrical wire arrays are made with 4 and 8 gold 10µm thick wire. The z-pinch radiates approximately 12-16kj of x-ray energy, with x-ray photons under 1Kev in energy. The photoionized plasma is measured via x-ray absorption spectroscopy and interferometry. A Mach-Zehnder interferometer is used to the measure neutral density of the jet prior to the zebra shot at a wavelength of 266 nm. A dual channel air-wedge shearing interferometer is used to measure electron density of the ionized gas jet during the shot, at wavelengths of 532nm and 266nm. Using a newly developed interferometric analysis tool, average ionization state maps of the plasma can be calculated. Interferometry for nitrogen and argon show an average ionization state in the range of 3-8. Preliminary x-ray absorption spectroscopy collected show neon absorption lines. This work was sponsored in part by DOE Office of Science Grant DE-SC0014451.

  4. Jet arrays in supersonic crossflow — An experimental study

    Science.gov (United States)

    Ali, Mohd Yousuf; Alvi, Farrukh

    2015-12-01

    Jet injection into a supersonic crossflow is a classical fluid dynamics problem with many engineering applications. Several experimental and numerical studies have been taken up to analyze the interaction of a single jet with the incoming crossflow. However, there is a dearth of the literature on the interaction of multiple jets with one another and with the crossflow. Jets in a supersonic crossflow are known to produce a three-dimensional bow-shock structure due to the blockage of the flow. Multiple jets in a streamwise linear array interact with both one another and the incoming supersonic flow. In this paper, a parametric study is carried out to analyze the effect of microjet (sub-mm diameter) injection in a Mach 1.5 supersonic crossflow using flow visualization and velocity field measurements. The variation of the microjet orifice diameter and spacing within an array is used to study the three-dimensional nature of the flow field around the jets. The strength of the microjet-generated shock, scaling of the shock wave angle with the momentum coefficient, averaged streamwise, spanwise, and cross-stream velocity fields, and microjet array trajectories are detailed in the paper. It was found that shock angles of the microjet-generated shocks scale with the momentum coefficient for the three actuator configurations tested. As the microjets issue in the crossflow, a pair of longitudinal counter-rotating vortices (CVPs) are formed. The vortex pairs remain coherent for arrays with larger spanwise spacing between the micro-orifices and exhibit significant three-dimensionality similar to that of a single jet in crossflow. As the spacing between the jets is reduced, the CVPs merge resulting in a more two-dimensional flow field. The bow shock resulting from microjet injection also becomes nearly two-dimensional as the spacing between the micro-orifices is reduced. Trajectory estimations yield that microjets in an array have similar penetration as single jets. A notional

  5. Supersonic Testing of 0.8 m Disk Gap Band Parachutes in the Wake of a 70 Deg Sphere Cone Entry Vehicle

    Science.gov (United States)

    Sengupta, Anita; Wernet, Mark; Roeder, James; Kelsch, Richard; Witkowski, Al; Jones, Thomas

    2009-01-01

    Supersonic wind tunnel testing of Viking-type 0.8 m Disk-Gap-Band (DGB) parachutes was conducted in the NASA Glenn Research Center 10'x10' wind-tunnel. The tests were conducted in support of the Mars Science Laboratory Parachute Decelerator System development and qualification program. The aerodynamic coupling of the entry-vehicle wake to parachute flow-field is under investigation to determine the cause and functional dependence of a supersonic canopy breathing phenomenon referred to as area oscillations, characteristic of DGB's above Mach 1.5 operation. Four percent of full-scale parachutes (0.8 m) were constructed similar to the flight-article in material and construction techniques. The parachutes were attached to a 70-deg sphere-cone entry-vehicle to simulate the Mars flight configuration. The parachutes were tested in the wind-tunnel from Mach 2 to 2.5 in a Reynolds number range of 2x105 to 1x106, representative of a Mars deployment. Three different test configurations were investigated. In the first two configurations, the parachutes were constrained horizontally through the vent region to measure canopy breathing and wake interaction for fixed trim angles of 0 and 10 degrees from the free-stream. In the third configuration the parachute was unconstrained, permitted to trim and cone, similar to free-flight (but capsule motion is constrained), varying its alignment relative to the entry-vehicle wake. Non-intrusive test diagnostics were chosen to quantify parachute performance and provide insight into the flow field structure. An in-line loadcell provided measurement of unsteady and mean drag. Shadowgraph of the upstream parachute flow field was used to capture bow-shock motion and wake coupling. Particle image velocimetry provided first and second order flow field statistics over a planar region of the flow field, just upstream of the parachute. A photogrammetric technique was used to quantify fabric motion using multiple high speed video cameras to record

  6. Progress Toward Analytic Predictions of Supersonic Hydrocarbon-Air Combustion: Computation of Ignition Times and Supersonic Mixing Layers

    Science.gov (United States)

    Sexton, Scott Michael

    Combustion in scramjet engines is faced with the limitation of brief residence time in the combustion chamber, requiring fuel and preheated air streams to mix and ignite in a matter of milliseconds. Accurate predictions of autoignition times are needed to design reliable supersonic combustion chambers. Most efforts in estimating non-premixed autoignition times have been devoted to hydrogen-air mixtures. The present work addresses hydrocarbon-air combustion, which is of interest for future scramjet engines. Computation of ignition in supersonic flows requires adequate characterization of ignition chemistry and description of the flow, both of which are derived in this work. In particular, we have shown that activation energy asymptotics combined with a previously derived reduced chemical kinetic mechanism provides analytic predictions of autoignition times in homogeneous systems. Results are compared with data from shock tube experiments, and previous expressions which employ a fuel depletion criterion. Ignition in scramjet engines has a strong dependence on temperature, which is found by perturbing the chemically frozen mixing layer solution. The frozen solution is obtained here, accounting for effects of viscous dissipation between the fuel and air streams. We investigate variations of thermodynamic and transport properties, and compare these to simplified mixing layers which neglect these variations. Numerically integrating the mixing layer problem reveals a nonmonotonic temperature profile, with a peak occurring inside the shear layer for sufficiently high Mach numbers. These results will be essential in computation of ignition distances in supersonic combustion chambers.

  7. Lagrangian solution of supersonic real gas flows

    Science.gov (United States)

    Loh, Ching-Yuen; Liou, Meng-Sing

    1993-01-01

    The present extention of a Lagrangian approach of the Riemann solution procedure, which was originally proposed for perfect gases, to real gases, is nontrivial and requires the development of an exact real-gas Riemann solver for the Lagrangian form of the conservation laws. Calculations including complex wave interactions of various types were conducted to test the accuracy and robustness of the approach. Attention is given to the case of 2D oblique waves' capture, where a slip line is clearly in evidence; the real gas effect is demonstrated in the case of a generic engine nozzle.

  8. Optimal locations of piezoelectric patches for supersonic flutter control of honeycomb sandwich panels, using the NSGA-II method

    International Nuclear Information System (INIS)

    Nezami, M; Gholami, B

    2016-01-01

    The active flutter control of supersonic sandwich panels with regular honeycomb interlayers under impact load excitation is studied using piezoelectric patches. A non-dominated sorting-based multi-objective evolutionary algorithm, called non-dominated sorting genetic algorithm II (NSGA-II) is suggested to find the optimal locations for different numbers of piezoelectric actuator/sensor pairs. Quasi-steady first order supersonic piston theory is employed to define aerodynamic loading and the p-method is applied to find the flutter bounds. Hamilton’s principle in conjunction with the generalized Fourier expansions and Galerkin method are used to develop the dynamical model of the structural systems in the state-space domain. The classical Runge–Kutta time integration algorithm is then used to calculate the open-loop aeroelastic response of the system. The maximum flutter velocity and minimum voltage applied to actuators are calculated according to the optimal locations of piezoelectric patches obtained using the NSGA-II and then the proportional feedback is used to actively suppress the closed loop system response. Finally the control effects, using the two different controllers, are compared. (paper)

  9. Lagrangian solution of supersonic real gas flows

    International Nuclear Information System (INIS)

    Loh, Chingyuen; Liou, Mengsing

    1993-01-01

    This paper details the procedure of the real gas Riemann solution in the Lagrangian approach originally proposed by Loh and Hui for perfect gases. The extension to real gases is nontrivial and requires substantial development of an exact real-gas Riemann solver for the Lagrangian form of conservation laws. The first-order Gudonov scheme is enhanced for accuracy by adding limited anti-diffusive terms according to Sweby. Extensive calculations were made to test the accuracy and robustness of the present real gas Lagrangian approach, including complex wave interactions of different types. The accuracy for capturing 2D oblique waves and slip line is clearly demonstrated. In addition, we also show the real gas effect in a generic engine nozzle

  10. Conceptual design of high speed supersonic aircraft: A brief review on SR-71 (Blackbird) aircraft

    Science.gov (United States)

    Xue, Hui; Khawaja, H.; Moatamedi, M.

    2014-12-01

    The paper presents the conceptual design of high-speed supersonic aircraft. The study focuses on SR-71 (Blackbird) aircraft. The input to the conceptual design is a mission profile. Mission profile is a flight profile of the aircraft defined by the customer. This paper gives the SR-71 aircraft mission profile specified by US air force. Mission profile helps in defining the attributes the aircraft such as wing profile, vertical tail configuration, propulsion system, etc. Wing profile and vertical tail configurations have direct impact on lift, drag, stability, performance and maneuverability of the aircraft. A propulsion system directly influences the performance of the aircraft. By combining the wing profile and the propulsion system, two important parameters, known as wing loading and thrust to weight ratio can be calculated. In this work, conceptual design procedure given by D. P. Raymer (AIAA Educational Series) is applied to calculate wing loading and thrust to weight ratio. The calculated values are compared against the actual values of the SR-71 aircraft. Results indicates that the values are in agreement with the trend of developments in aviation.

  11. Interaction of Eu, Th and U with bentonite colloids in presence of humic acid: a flow-field flow fractionation study

    Energy Technology Data Exchange (ETDEWEB)

    Bouby, M.; Geckeis, H.; Schaefer, Th. [Institut fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe (Germany); Mihai, S. [Institut fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe (Germany)]|[Politehnica University, Faculty of Industrial Chemistry, Calea Grivitei 132, Bucharest 78122 (Romania); Fanghaenell, Th. [Institut fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, Postfach 3640, D-76021 Karlsruhe (Germany)]|[Physikalisch-Chemisches Institut, Ruprecht-Karls-Universitaet, Im Neuenheimer Feld 253, D- 69120 Heidelberg (Germany)

    2005-07-01

    Full text of publication follows: The actinide mobility in the far-field of a repository site can be strongly influenced by the presence of colloidal species. Field migration experiments at the Grimsel Test Site under low ionic strength (I=10{sup -3} mol/L) and high pH ({approx}9.6) conditions have demonstrated a considerable clay colloid-mediated actinide(III/IV) migration [1]. However, those studies rendered it necessary to take the kinetics of notably the actinide-colloid interaction and colloid stability into account [2]. In the present study, we examine the stability of bentonite clay colloids in natural Grimsel groundwater and their interaction with Cs(I), Eu(III), Th(IV) and U(VI) (conc. {approx} 10{sup -8} mol/L). Experiments cover 12 months contact times and are performed under anoxic conditions. Humic acid (Gohy-573) is added after different contact times as a competing ligand and the time dependent metal ion desorption is followed. Dedicated experiments and thermodynamic speciation calculations are performed to estimate the metal ion speciation within the colloid system. As the experimental metal ion speciation (i.e. differentiation of clay-colloid bound, humic colloid bound and dissolved metal ion species) at the given low concentration conditions is hardly possible by spectroscopic methods, we use Asymmetric Flow-Field Flow Fractionation coupled to UV-Vis spectrophotometry and ICP-MS detection. Unexpectedly, it is found that small-sized bentonite colloids (< 50 nm) not visible by light scattering (PCS) analysis agglomerate and finally reach a steady-state colloid size distribution (50-200 nm) after {approx} 3 months. As estimated from known thermodynamic data and experimentally determined K{sub d}-values, Cs and U do not interact significantly with bentonite colloids, while Th and Eu do. Eu desorption from clay colloids by humic acid is delayed significantly upon increasing the clay colloid-Eu contact time up to several months. Nevertheless, estimated

  12. Effect of delta wing on the particle flow in a novel gas supersonic separator

    DEFF Research Database (Denmark)

    Wen, Chuang; Yang, Yan; Walther, Jens Honore

    2016-01-01

    The present work presents numerical simulations of the complex particle motion in a supersonic separator with a delta wing located in the supersonic flow. The effect of the delta wing on the strong swirling flow is analysed using the Discrete Particle Method. The results show that the delta wings...

  13. Design and Numerical Calculation of Variable Test Section for Small Supersonic Wind Tunnel

    Directory of Open Access Journals (Sweden)

    Václav DVOŘÁK

    2010-12-01

    Full Text Available The paper is concerned with numerical modelling of transition in a separated boundary layer. The model of laminar/turbulent transition is based on the combination of empirical terms determining position of the transition and averaged Navier – Stokes equations closed by the k – ω SST turbulence model. The model of transition is applied in computation of 2D flow past NACA63A421 airfoil. Computation is performed using the commercial code ANSYS Fluent 6.3.26, in which the transition method is implemented as a User-Defined-Function. Computed distributions of Cp along the airfoil are verified by comparison with experimental data, which were obtained by measurements in a closed circuit wind tunnel at the constant Reynolds number and several angles of attack. Comparisons prove applicability of the implemented transitional model.

  14. Supersonic flutter suppression of electrorheological fluid-based adaptive panels resting on elastic foundations using sliding mode control

    International Nuclear Information System (INIS)

    Hasheminejad, Seyyed M; Nezami, M; Aryaee Panah, M E

    2012-01-01

    Brief reviews on suppressing panel flutter vibrations by various active control strategies as well as utilization tunable electrorheological fluids (ERFs) for vibration control of structural systems are presented. Active suppression of the supersonic flutter motion of a simply supported sandwich panel with a tunable ERF interlayer, and coupled to an elastic foundation, is subsequently investigated. The structural formulation is based on the classical beam theory along with the Winkler–Pasternak foundation model, the ER fluid core is modeled as a first-order Kelvin–Voigt material, and the quasi-steady first-order supersonic piston theory is employed to describe the aerodynamic loading. Hamilton’s principle is used to derive a set of fully coupled dynamic equations of motion. The generalized Fourier expansions in conjunction with the Galerkin method are then employed to formulate the governing equations in the state space domain. The critical dynamic pressures at which unstable panel oscillations (coalescence of eigenvalues) occur are obtained via the p-method for selected applied electric field strengths (E = 0,2,4 kV mm −1 ). The classical Runge–Kutta time integration algorithm is subsequently used to calculate the open-loop aeroelastic response of the system in various basic loading configurations (i.e. uniformly distributed blast, gust, sonic boom, and step loads), with or without an interacting soft/stiff elastic foundation. Finally, a sliding mode control synthesis (SMC) involving the first six natural modes of the structural system is set up to actively suppress the closed-loop system response in supersonic flight conditions and under the imposed excitations. Simulation results demonstrate performance, effectiveness, and insensitivity with respect to the spillover of the proposed SMC-based control system. Limiting cases are considered and good agreements with the data available in the literature as well as with the computations made by using the

  15. Declination Calculator

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Declination is calculated using the current International Geomagnetic Reference Field (IGRF) model. Declination is calculated using the current World Magnetic Model...

  16. Unsteady Flow in a Supersonic Turbine with Variable Specific Heats

    Science.gov (United States)

    Dorney, Daniel J.; Griffin, Lisa W.; Huber, Frank; Sondak, Douglas L.; Turner, James (Technical Monitor)

    2001-01-01

    Modern high-work turbines can be compact, transonic, supersonic, counter-rotating, or use a dense drive gas. The vast majority of modern rocket turbine designs fall into these Categories. These turbines usually have large temperature variations across a given stage, and are characterized by large amounts of flow unsteadiness. The flow unsteadiness can have a major impact on the turbine performance and durability. For example, the Space Transportation Main Engine (STME) fuel turbine, a high work, transonic design, was found to have an unsteady inter-row shock which reduced efficiency by 2 points and increased dynamic loading by 24 percent. The Revolutionary Reusable Technology Turbopump (RRTT), which uses full flow oxygen for its drive gas, was found to shed vortices with such energy as to raise serious blade durability concerns. In both cases, the sources of the problems were uncovered (before turbopump testing) with the application of validated, unsteady computational fluid dynamics (CFD) to the designs. In the case of the RRTT and the Alternate Turbopump Development (ATD) turbines, the unsteady CFD codes have been used not just to identify problems, but to guide designs which mitigate problems due to unsteadiness. Using unsteady flow analyses as a part of the design process has led to turbine designs with higher performance (which affects temperature and mass flow rate) and fewer dynamics problems. One of the many assumptions made during the design and analysis of supersonic turbine stages is that the values of the specific heats are constant. In some analyses the value is based on an average of the expected upstream and downstream temperatures. In stages where the temperature can vary by 300 to 500 K, however, the assumption of constant fluid properties may lead to erroneous performance and durability predictions. In this study the suitability of assuming constant specific heats has been investigated by performing three-dimensional unsteady Navier

  17. Effect of Axisymmetric Aft Wall Angle Cavity in Supersonic Flow Field

    Science.gov (United States)

    Jeyakumar, S.; Assis, Shan M.; Jayaraman, K.

    2018-03-01

    Cavity plays a significant role in scramjet combustors to enhance mixing and flame holding of supersonic streams. In this study, the characteristics of axisymmetric cavity with varying aft wall angles in a non-reacting supersonic flow field are experimentally investigated. The experiments are conducted in a blow-down type supersonic flow facility. The facility consists of a supersonic nozzle followed by a circular cross sectional duct. The axisymmetric cavity is incorporated inside the duct. Cavity aft wall is inclined with two consecutive angles. The performance of the aft wall cavities are compared with rectangular cavity. Decreasing aft wall angle reduces the cavity drag due to the stable flow field which is vital for flame holding in supersonic combustor. Uniform mixing and gradual decrease in stagnation pressure loss can be achieved by decreasing the cavity aft wall angle.

  18. Fan Noise for a Concept Commercial Supersonic Transport

    Science.gov (United States)

    Stephens, David

    2017-01-01

    NASA is currently studying a commercial supersonic transport (CST) aircraft that could carry 35+ passengers at Mach 1.6+ with a 4000+nm range. The aircraft should also meet environmental goals for sonic boom, airport noise and emissions at cruise. With respect to airport noise, considerable effort has been put into predicting the noise due to the jet exhaust. This report describes an internal NASA effort to consider the contribution of fan noise to the overall engine noise of this class of aircraft.

  19. CFD investigations on supersonic ejectors for refrigeration applications

    International Nuclear Information System (INIS)

    Bartosiewicz, Y.; Aidoun, Z.; Mercadier, Y.

    2004-01-01

    This paper presents numerical results of a supersonic ejector for refrigeration applications. One of the interesting features is that the current model is based on the NIST properties for the R142b refrigerant: to the authors knowledge, it is the first paper dealing with a local CFD model which takes into account shock-boundary layer interactions in a real refrigerant. The numerical results put demonstrate the crucial role of the secondary nozzle for the mixing rate performance. In addition, these results point out the need of an extensive validation of the turbulence model, especially in the modeling of the off-design mode. (author)

  20. Toward Active Control of Noise from Hot Supersonic Jets

    Science.gov (United States)

    2014-04-21

    Mechanisms AGARD - CP -131, 1974, pp. 13.1-13.12. [23] Goldstein, M.E., "On identifying the true sources of aerodynamic sound," Journal of Fluid Mechanics Vol...either constant or begins to decay. For the resampled data (1/8 inch microphones resampled at 100 kHz), the change in 7( 73 ) follows the originally...supersonic jet and their acoustic radiation," Journal of Fluid Mechanics, Vol. 69, No.l, 1975, pp. 73 95. [5] Tain, C. K. W., "Mach wave radiation from high

  1. Viscoelasticity evaluation of rubber by surface reflection of supersonic wave.

    Science.gov (United States)

    Omata, Nobuaki; Suga, Takahiro; Furusawa, Hirokazu; Urabe, Shinichi; Kondo, Takeru; Ni, Qing-Qing

    2006-12-22

    The main characteristic of rubber is a viscoelasticity. So it is important to research the characteristic of the viscoelasticity of the high frequency band for the friction between a rubber material and the hard one with roughness, for instance, the tire and the road. As for the measurement of the viscoelasticity of rubber, DMA (dynamic mechanical analysis) is general. However, some problems are pointed out to the measurement of the high frequency band by DMA. Then, we evaluated the viscoelasticity characteristic by the supersonic wave measurement. However, attenuation of rubber is large, and when the viscoelasticity is measured by the supersonic wave therefore, it is inconvenient and limited in a past method by means of bottom reflection. In this report, we tried the viscoelasticity evaluation by the method of using complex surface reflection coefficient and we compared with the friction coefficient under wide-range friction velocity. As a result, some relationships had been found for two properties. We report the result that character of viscoelasticity of rubber was comparable to friction coefficient.

  2. Thermonuclear dynamo inside ultracentrifuge with supersonic plasma flow stabilization

    Energy Technology Data Exchange (ETDEWEB)

    Winterberg, F. [University of Nevada, Reno, Reno, Nevada (United States)

    2016-01-15

    Einstein's general theory of relativity implies the existence of virtual negative masses in the rotational reference frame of an ultracentrifuge with the negative mass density of the same order of magnitude as the positive mass density of a neutron star. In an ultracentrifuge, the repulsive gravitational field of this negative mass can simulate the attractive positive mass of a mini-neutron star, and for this reason can radially confine a dense thermonuclear plasma placed inside the centrifuge, very much as the positive mass of a star confines its plasma by its own attractive gravitational field. If the centrifuge is placed in an externally magnetic field to act as the seed field of a magnetohydrodynamic generator, the configuration resembles a magnetar driven by the release of energy through nuclear fusion, accelerating the plasma to supersonic velocities, with the magnetic field produced by the thermomagnetic Nernst effect insulating the hot plasma from the cold wall of the centrifuge. Because of the supersonic flow and the high plasma density the configuration is stable.

  3. Thermonuclear dynamo inside ultracentrifuge with supersonic plasma flow stabilization

    Science.gov (United States)

    Winterberg, F.

    2016-01-01

    Einstein's general theory of relativity implies the existence of virtual negative masses in the rotational reference frame of an ultracentrifuge with the negative mass density of the same order of magnitude as the positive mass density of a neutron star. In an ultracentrifuge, the repulsive gravitational field of this negative mass can simulate the attractive positive mass of a mini-neutron star, and for this reason can radially confine a dense thermonuclear plasma placed inside the centrifuge, very much as the positive mass of a star confines its plasma by its own attractive gravitational field. If the centrifuge is placed in an externally magnetic field to act as the seed field of a magnetohydrodynamic generator, the configuration resembles a magnetar driven by the release of energy through nuclear fusion, accelerating the plasma to supersonic velocities, with the magnetic field produced by the thermomagnetic Nernst effect insulating the hot plasma from the cold wall of the centrifuge. Because of the supersonic flow and the high plasma density the configuration is stable.

  4. Thermonuclear dynamo inside ultracentrifuge with supersonic plasma flow stabilization

    International Nuclear Information System (INIS)

    Winterberg, F.

    2016-01-01

    Einstein's general theory of relativity implies the existence of virtual negative masses in the rotational reference frame of an ultracentrifuge with the negative mass density of the same order of magnitude as the positive mass density of a neutron star. In an ultracentrifuge, the repulsive gravitational field of this negative mass can simulate the attractive positive mass of a mini-neutron star, and for this reason can radially confine a dense thermonuclear plasma placed inside the centrifuge, very much as the positive mass of a star confines its plasma by its own attractive gravitational field. If the centrifuge is placed in an externally magnetic field to act as the seed field of a magnetohydrodynamic generator, the configuration resembles a magnetar driven by the release of energy through nuclear fusion, accelerating the plasma to supersonic velocities, with the magnetic field produced by the thermomagnetic Nernst effect insulating the hot plasma from the cold wall of the centrifuge. Because of the supersonic flow and the high plasma density the configuration is stable

  5. Jet Noise Modeling for Supersonic Business Jet Application

    Science.gov (United States)

    Stone, James R.; Krejsa, Eugene A.; Clark, Bruce J.

    2004-01-01

    This document describes the development of an improved predictive model for coannular jet noise, including noise suppression modifications applicable to small supersonic-cruise aircraft such as the Supersonic Business Jet (SBJ), for NASA Langley Research Center (LaRC). For such aircraft a wide range of propulsion and integration options are under consideration. Thus there is a need for very versatile design tools, including a noise prediction model. The approach used is similar to that used with great success by the Modern Technologies Corporation (MTC) in developing a noise prediction model for two-dimensional mixer ejector (2DME) nozzles under the High Speed Research Program and in developing a more recent model for coannular nozzles over a wide range of conditions. If highly suppressed configurations are ultimately required, the 2DME model is expected to provide reasonable prediction for these smaller scales, although this has not been demonstrated. It is considered likely that more modest suppression approaches, such as dual stream nozzles featuring chevron or chute suppressors, perhaps in conjunction with inverted velocity profiles (IVP), will be sufficient for the SBJ.

  6. Investigation of Cooling Water Injection into Supersonic Rocket Engine Exhaust

    Science.gov (United States)

    Jones, Hansen; Jeansonne, Christopher; Menon, Shyam

    2017-11-01

    Water spray cooling of the exhaust plume from a rocket undergoing static testing is critical in preventing thermal wear of the test stand structure, and suppressing the acoustic noise signature. A scaled test facility has been developed that utilizes non-intrusive diagnostic techniques including Focusing Color Schlieren (FCS) and Phase Doppler Particle Anemometry (PDPA) to examine the interaction of a pressure-fed water jet with a supersonic flow of compressed air. FCS is used to visually assess the interaction of the water jet with the strong density gradients in the supersonic air flow. PDPA is used in conjunction to gain statistical information regarding water droplet size and velocity as the jet is broken up. Measurement results, along with numerical simulations and jet penetration models are used to explain the observed phenomena. Following the cold flow testing campaign a scaled hybrid rocket engine will be constructed to continue tests in a combusting flow environment similar to that generated by the rocket engines tested at NASA facilities. LaSPACE.

  7. Garden hose separation of gaseous isotopes. Part II. Supersonic accelerations

    International Nuclear Information System (INIS)

    Wang, C.G.; Davis, A.G.M.

    1979-01-01

    A mechanical process for separating gaseous mixtures according to their respective molecular weights, by a variation of the time-of-flight process, is proposed. The separative apparatus consists of several sets of nozzle-deflector combinations surrounded by a stationary collector housed in an evacuated chamber. From a rotating supersonic nozzle, a contiguous plurality of successive groups of molecules is ejected to form a continuous stream of the mixture. The molecules of each group of molecules are allowed to accelerate for a predetermined period of time following their supersonic expansion, thereby allowing each group of molecules to form a generally spherical configuration, the outer radius of which will be enriched in molecules of lighter mass, relative to lesser radii. A deflector means co-rotating with the nozzle is used to deflect molecules that have been allowed to move for the predetermined period of time in accordance with their expansion velocities, from at least one desired portion of the stream, and a stationary collector means is disposed to receive the deflected molecules. The estimated separative work produced from such a unit is about the same or better than that of a modern giant diffuser of similar dimensions. However, with an essentially empty chamber, the unit capital cost as well as the energy required is competitive with any of the well-known methods, mechanical or otherwise

  8. The electron beam diagnostic of the clustered supersonic nitrogen jets

    Science.gov (United States)

    Avtaeva, S. V.; Yakovleva, T. S.; Kalyada, V. V.; Zarvin, A. E.

    2017-11-01

    Axial and radial distributions of the rotational temperature and density of N2 molecules in supersonic nitrogen jets formed with conic nozzles (critical diameters dcr of 0.17 and 0.21 mm) were studied using the electron beam fluorescence technique at stagnation pressures P0 of 0.1-0.6 MPa. A rotational temperature Tr , equaling a gas temperature Tg owing to fast RT relaxation, was obtained using the rotational line relative intensity distribution in (0-1) vibrational band of the N2 first negative system. Gas density profiles in the jets were obtained using the integral intensity of the band. It is found, Tr at the nozzle outlet is of the order of a few tens of Kelvin and at further expansion Tr drops up to 15-20K at distance of (100-200) dcr . The gas temperature and density distributions in the studied supersonic nitrogen jets are not similar to the isentropic distributions. It is shown that the lower is the stagnation pressure the faster the gas density and temperature decrease with distance from the nozzle. Increase in P0 leads to elevating Tg in the jets. A reason for this effect may be cluster formation in the jets. Estimations of cluster mean sizes in the jets using Hagena’s parameter show presence of large clusters (M≥200) at P0 = 0.4-0.6 MPa.

  9. Steady supersonic rotation in the Maryland Centrifugal Experiment

    International Nuclear Information System (INIS)

    Ellis, R.F.; Messer, S.; Case, A.; DeSilva, A.; Elton, R.; Ghosh, J.; Griem, H.; Gupta, D.; Hassam, A.; Lunsford, R.; McLaren, R.; Rodgers, J.; Teodorescu, C.

    2005-01-01

    The Maryland Centrifugal Experiment (MCX) studies enhanced confinement and stability produced by sheared supersonic rotation about a linear confining magnetic field. MCX has a mirror geometry of 2.5 m length, mirror ratio 2-20, maximum mirror field 1.9T, maximum midplane field 0.33T. Biasing of an inner electrode relative to the outer wall produces a radial electric field which drives azimuthal rotation. MCX has achieved high density (n>10 20 m -3 ) fully ionized plasmas rotating supersonically with velocities of ∼100 km/sec for times exceeding 8 ms under a wide range of conditions. Ion temperatures are 30 eV and confinement times ∼100 microseconds. Sonic Mach numbers are 1-2 and Alfven Mach numbers somewhat less than 0.5 for standard discharges. Plasmas remain grossly stable, or steady, for many milliseconds, much longer than MHD instability timescales for MCX, though significant magnetic fluctuations are clearly seen on magnetic probes. Recently MCX has demonstrated an enhanced mode of operation with sonic Mach numbers greater than 3, confinement times of several hundred microseconds and Alfven Mach numbers near one. (author)

  10. Supersonic liquid jets: Their generation and shock wave characteristics

    Science.gov (United States)

    Pianthong, K.; Zakrzewski, S.; Behnia, M.; Milton, B. E.

    The generation of high-speed liquid (water and diesel fuel) jets in the supersonic range using a vertical single-stage powder gun is described. The effect of projectile velocity and mass on the jet velocity is investigated experimentally. Jet exit velocities for a set of nozzle inner profiles (e.g. straight cone with different cone angles, exponential, hyperbolic etc.) are compared. The optimum condition to achieve the maximum jet velocity and hence better atomization and mixing is then determined. The visual images of supersonic diesel fuel jets (velocity about 2000 m/s) were obtained by the shadowgraph method. This provides better understanding of each stage of the generation of the jets and makes the study of their characteristics and the potential for auto-ignition possible. In the experiments, a pressure relief section has been used to minimize the compressed air wave ahead of the projectile. To clarify the processes inside the section, additional experiments have been performed with the use of the shadowgraph method, showing the projectile travelling inside and leaving the pressure relief section at a velocity of about 1100 m/s.

  11. Two-temperature chemically non-equilibrium modelling of an air supersonic ICP

    Energy Technology Data Exchange (ETDEWEB)

    El Morsli, Mbark; Proulx, Pierre [Laboratoire de Modelisation de Procedes Chimiques par Ordinateur Oppus, Departement de Genie Chimique, Universite de Sherbrooke (Ciheam) J1K 2R1 (Canada)

    2007-08-21

    In this work, a non-equilibrium mathematical model for an air inductively coupled plasma torch with a supersonic nozzle is developed without making thermal and chemical equilibrium assumptions. Reaction rate equations are written, and two coupled energy equations are used, one for the calculation of the translational-rotational temperature T{sub hr} and one for the calculation of the electro-vibrational temperature T{sub ev}. The viscous dissipation is taken into account in the translational-rotational energy equation. The electro-vibrational energy equation also includes the pressure work of the electrons, the Ohmic heating power and the exchange due to elastic collision. Higher order approximations of the Chapman-Enskog method are used to obtain better accuracy for transport properties, taking advantage of the most recent sets of collisions integrals available in the literature. The results obtained are compared with those obtained using a chemical equilibrium model and a one-temperature chemical non-equilibrium model. The influence of the power and the pressure chamber on the chemical and thermal non-equilibrium is investigated.

  12. Numerical simulation of the gas-liquid interaction of a liquid jet in supersonic crossflow

    Science.gov (United States)

    Li, Peibo; Wang, Zhenguo; Sun, Mingbo; Wang, Hongbo

    2017-05-01

    The gas-liquid interaction process of a liquid jet in supersonic crossflow with a Mach number of 1.94 was investigated numerically using the Eulerian-Lagrangian method. The KH (Kelvin-Helmholtz) breakup model was used to calculate the droplet stripping process, and the secondary breakup process was simulated by the competition of RT (Rayleigh-Taylor) breakup model and TAB (Taylor Analogy Breakup) model. A correction of drag coefficient was proposed by considering the compressible effects and the deformation of droplets. The location and velocity models of child droplets after breakup were improved according to droplet deformation. It was found that the calculated spray features, including spray penetration, droplet size distribution and droplet velocity profile agree reasonably well with the experiment. Numerical results revealed that the streamlines of air flow could intersect with the trajectory of droplets and are deflected towards the near-wall region after they enter into spray zone around the central plane. The analysis of gas-liquid relative velocity and droplet deformation suggested that the breakup of droplets mainly occurs around the front region of the spray where gathered a large number of droplets with different sizes. The liquid trailing phenomenon of jet spray which has been discovered by the previous experiment was successfully captured, and a reasonable explanation was given based on the analysis of gas-liquid interaction process.

  13. Predicting membrane flux decline from complex mixtures using flow-field flow fractionation measurements and semi-empirical theory.

    Science.gov (United States)

    Pellegrino, J; Wright, S; Ranvill, J; Amy, G

    2005-01-01

    Flow-Field Flow Fractionation (FI-FFF) is an idealization of the cross flow membrane filtration process in that, (1) the filtration flux and crossflow velocity are constant from beginning to end of the device, (2) the process is a relatively well-defined laminar-flow hydrodynamic condition, and (3) the solutes are introduced as a pulse-input that spreads due to interactions with each other and the membrane in the dilute-solution limit. We have investigated the potential for relating FI-FFF measurements to membrane fouling. An advection-dispersion transport model was used to provide 'ideal' (defined as spherical, non-interacting solutes) solute residence time distributions (RTDs) for comparison with 'real' RTDs obtained experimentally at different cross-field velocities and solution ionic strength. An RTD moment analysis based on a particle diameter probability density function was used to extract "effective" characteristic properties, rather than uniquely defined characteristics, of the standard solute mixture. A semi-empirical unsteady-state, flux decline model was developed that uses solute property parameters. Three modes of flux decline are included: (1) concentration polarization, (2) cake buildup, and (3) adsorption on/in pores, We have used this model to test the hypothesis-that an analysis of a residence time distribution using FI-FFF can describe 'effective' solute properties or indices that can be related to membrane flux decline in crossflow membrane filtration. Constant flux filtration studies included the changes of transport hydrodynamics (solvent flux to solute back diffusion (J/k) ratios), solution ionic strength, and feed water composition for filtration using a regenerated cellulose ultrafiltration membrane. Tests of the modeling hypothesis were compared with experimental results from the filtration measurements using several correction parameters based on the mean and variance of the solute RTDs. The corrections used to modify the boundary layer

  14. A Level-set based framework for viscous simulation of particle-laden supersonic flows

    Science.gov (United States)

    Das, Pratik; Sen, Oishik; Jacobs, Gustaaf; Udaykumar, H. S.

    2017-06-01

    Particle-laden supersonic flows are important in natural and industrial processes, such as, volcanic eruptions, explosions, pneumatic conveyance of particle in material processing etc. Numerical study of such high-speed particle laden flows at the mesoscale calls for a numerical framework which allows simulation of supersonic flow around multiple moving solid objects. Only a few efforts have been made toward development of numerical frameworks for viscous simulation of particle-fluid interaction in supersonic flow regime. The current work presents a Cartesian grid based sharp-interface method for viscous simulations of interaction between supersonic flow with moving rigid particles. The no-slip boundary condition is imposed at the solid-fluid interfaces using a modified ghost fluid method (GFM). The current method is validated against the similarity solution of compressible boundary layer over flat-plate and benchmark numerical solution for steady supersonic flow over cylinder. Further validation is carried out against benchmark numerical results for shock induced lift-off of a cylinder in a shock tube. 3D simulation of steady supersonic flow over sphere is performed to compare the numerically obtained drag co-efficient with experimental results. A particle-resolved viscous simulation of shock interaction with a cloud of particles is performed to demonstrate that the current method is suitable for large-scale particle resolved simulations of particle-laden supersonic flows.

  15. CONTAIN calculations

    International Nuclear Information System (INIS)

    Scholtyssek, W.

    1995-01-01

    In the first phase of a benchmark comparison, the CONTAIN code was used to calculate an assumed EPR accident 'medium-sized leak in the cold leg', especially for the first two days after initiation of the accident. The results for global characteristics compare well with those of FIPLOC, MELCOR and WAVCO calculations, if the same materials data are used as input. However, significant differences show up for local quantities such as flows through leakages. (orig.)

  16. Production and characterization of supersonic carbon cluster beams

    International Nuclear Information System (INIS)

    Rohlfing, E.A.; Cox, D.M.; Kaldor, A.

    1984-01-01

    Laser vaporization of a substrate within the throat of a pulsed nozzle is used to generate a supersonic beam of carbon clusters. The neutral cluster beam is probed downstream by UV laser photoionization with time-of-flight mass analysis of the resulting photoions. Using graphite as the substrate, carbon clusters C/sub n/ for n = 1--190 have been produced having a distinctly bimodal cluster size distribution: (i) Both even and odd clusters for C/sub n/, 1 + /sub n/ signals are interpreted on the basis of cluster formation and stability arguments. Ionizing laser power dependences taken at several different photon energies are used to roughly bracket the carbon cluster ionization potentials, and, at high laser intensity, to observe the onset of multiphoton fragmentation. By treating the graphite rod with KOH, a greatly altered carbon cluster distribution with mixed carbon/potassium clusters of formula K 2 C/sub 2n/ is produced

  17. Overexpanded viscous supersonic jet interacting with a unilateral barrier

    Science.gov (United States)

    Dobrynin, B. M.; Maslennikov, V. G.; Sakharov, V. A.; Serova, E. V.

    1986-07-01

    The interaction of a two-dimensional supersonic jet with a unilateral barrier parallel to the flow symmetry plane was studied to account for effects due to gas viscosity and backgound-gas ejection from the region into which the jet expands. In the present experiments, the incident shock wave was reflected at the end of a shock tube equipped with a nozzle. The jet emerged into a pressure chamber 6 cu m in volume and the environmental pressure ratio of the flow in the quasi-stationary phase remained constant. The light source was an OGM-20 laser operating in the giant-pulse mode. Due to background-gas ejection, the gas density in the vicinity of the barrier is much less than on the unconfined side of the jet. The resulting flow is characterized by two distinct environmental pressure ratios: the flow is underexpanded near the barrier, while on the other side it is overexpanded.

  18. Supersonic Molecular Beam Optical Stark Spectroscopy of MnH.

    Science.gov (United States)

    Gengler, Jamie; Ma, Tongmei; Harrison, Jeremy; Steimle, Timothy

    2006-03-01

    The large moment of inertia, large magnetic moment, and possible large permanent electric dipole moment of manganese monohydride, MnH, makes it a prime candidate for ultra-cold molecule production via Stark deceleration and magnetic trapping. Here we report the first molecular beam production of MnH and the analysis of the Stark effect in the (0,0) A^7 π -- X^ 7σ^+ band. The sample was prepared by laser ablation of solid Mn in an H2 supersonic expansion. The low rotational temperature (MnH and the analysis of T.D. Varberg, J.A. Gray, R.W. Field, and A.J. Merer, J. Mol. Spec. 156, 296-318 (1992). I.E. Gordon, D.R.T. Appadoo, A. Shayesteh, K.A. Walker, and P.F. Bernath, J. Mol. Spec., 229, 145-149 (2005).

  19. Supersonic jets of hydrogen and helium for laser wakefield acceleration

    CERN Document Server

    Svensson, K.; Wojda, F.; Senje, L.; Burza, M.; Aurand, B.; Genoud, G.; Persson, A.; Wahlström, C.-G.; Lundh, O.

    2016-01-01

    The properties of laser wakefield accelerated electrons in supersonic gas flows of hydrogen and helium are investigated. At identical backing pressure, we find that electron beams emerging from helium show large variations in their spectral and spatial distributions, whereas electron beams accelerated in hydrogen plasmas show a higher degree of reproducibility. In an experimental investigation of the relation between neutral gas density and backing pressure, it is found that the resulting number density for helium is ∼30% higher than for hydrogen at the same backing pressure. The observed differences in electron beam properties between the two gases can thus be explained by differences in plasma electron density. This interpretation is verified by repeating the laser wakefield acceleration experiment using similar plasma electron densities for the two gases, which then yielded electron beams with similar properties.

  20. Supersonic Love waves in strong piezoelectrics of symmetry mm2

    International Nuclear Information System (INIS)

    Darinskii, A. N.; Weihnacht, M.

    2001-01-01

    A study has been made of the Love wave propagation on piezoelectric substrates of symmetry mm2. It has been shown that under certain conditions the velocity of the Love wave exceeds that of shear horizontal (SH) bulk waves in the substrate. This occurs when the slowness curve of SH bulk waves in the substrate either has a concavity or is convex with nearly zero curvature. For such 'supersonic' Love waves to appear, it is also required that the substrate as well as the layer be specially oriented and that their material constants fulfill a number of inequalities. Numerical computations have been carried out for a number of structures. The results of numerical computations have been compared with approximate analytical estimations. [copyright] 2001 American Institute of Physics

  1. Pitot-probe displacement in a supersonic turbulent boundary layer

    Science.gov (United States)

    Allen, J. M.

    1972-01-01

    Eight circular pitot probes ranging in size from 2 to 70 percent of the boundary-layer thickness were tested to provide experimental probe displacement results in a two-dimensional turbulent boundary layer at a nominal free-stream Mach number of 2 and unit Reynolds number of 8 million per meter. The displacement obtained in the study was larger than that reported by previous investigators in either an incompressible turbulent boundary layer or a supersonic laminar boundary layer. The large probes indicated distorted Mach number profiles, probably due to separation. When the probes were small enough to cause no appreciable distortion, the displacement was constant over most of the boundary layer. The displacement in the near-wall region decreased to negative displacement in some cases. This near-wall region was found to extend to about one probe diameter from the test surface.

  2. Variable geometry for supersonic mixed-compression inlets

    Science.gov (United States)

    Sorensen, N. E.; Latham, E. A.; Smeltzer, D. B.

    1974-01-01

    Study of two-dimensional and axisymmetric supersonic mixed-compression inlet systems has shown that the geometry of both systems can be varied to provide adequate transonic airflow to satisfy the airflow demand of most jet engines. Collapsing geometry systems for both types of inlet systems provide a generous amount of transonic airflow for any design Mach number inlet system. However, the mechanical practicality of collapsing centerbodies for axisymmetric inlet systems is doubtful. Therefore, translating centerbody axisymmetric inlets with auxiliary airflow systems to augment the transonic airflow capability are an attractive alternative. Estimates show that the capture mass-flow ratio at Mach number 1.0 can be increased approximately 0.20 for a very short axisymmetric inlet system designed for Mach number 2.37. With this increase in mass-flow ratio, even variable-cycle engine transonic airflow demand can be matched without oversizing the inlet at the design Mach number.

  3. Supersonic jets of hydrogen and helium for laser wakefield acceleration

    Directory of Open Access Journals (Sweden)

    K. Svensson

    2016-05-01

    Full Text Available The properties of laser wakefield accelerated electrons in supersonic gas flows of hydrogen and helium are investigated. At identical backing pressure, we find that electron beams emerging from helium show large variations in their spectral and spatial distributions, whereas electron beams accelerated in hydrogen plasmas show a higher degree of reproducibility. In an experimental investigation of the relation between neutral gas density and backing pressure, it is found that the resulting number density for helium is ∼30% higher than for hydrogen at the same backing pressure. The observed differences in electron beam properties between the two gases can thus be explained by differences in plasma electron density. This interpretation is verified by repeating the laser wakefield acceleration experiment using similar plasma electron densities for the two gases, which then yielded electron beams with similar properties.

  4. CARS Temperature Measurements in a Combustion-Heated Supersonic Jet

    Science.gov (United States)

    Tedder, S. A.; Danehy, P. M.; Magnotti, G.; Cutler, A. D.

    2009-01-01

    Measurements were made in a combustion-heated supersonic axi-symmetric free jet from a nozzle with a diameter of 6.35 cm using dual-pump Coherent Anti-Stokes Raman Spectroscopy (CARS). The resulting mean and standard deviation temperature maps are presented. The temperature results show that the gas temperature on the centerline remains constant for approximately 5 nozzle diameters. As the heated gas mixes with the ambient air further downstream the mean temperature decreases. The standard deviation map shows evidence of the increase of turbulence in the shear layer as the jet proceeds downstream and mixes with the ambient air. The challenges of collecting data in a harsh environment are discussed along with influences to the data. The yield of the data collected is presented and possible improvements to the yield is presented are discussed.

  5. An efficient unstructured WENO method for supersonic reactive flows

    Science.gov (United States)

    Zhao, Wen-Geng; Zheng, Hong-Wei; Liu, Feng-Jun; Shi, Xiao-Tian; Gao, Jun; Hu, Ning; Lv, Meng; Chen, Si-Cong; Zhao, Hong-Da

    2018-03-01

    An efficient high-order numerical method for supersonic reactive flows is proposed in this article. The reactive source term and convection term are solved separately by splitting scheme. In the reaction step, an adaptive time-step method is presented, which can improve the efficiency greatly. In the convection step, a third-order accurate weighted essentially non-oscillatory (WENO) method is adopted to reconstruct the solution in the unstructured grids. Numerical results show that our new method can capture the correct propagation speed of the detonation wave exactly even in coarse grids, while high order accuracy can be achieved in the smooth region. In addition, the proposed adaptive splitting method can reduce the computational cost greatly compared with the traditional splitting method.

  6. Particle acceleration via reconnection processes in the supersonic solar wind

    International Nuclear Information System (INIS)

    Zank, G. P.; Le Roux, J. A.; Webb, G. M.; Dosch, A.; Khabarova, O.

    2014-01-01

    An emerging paradigm for the dissipation of magnetic turbulence in the supersonic solar wind is via localized small-scale reconnection processes, essentially between quasi-2D interacting magnetic islands. Charged particles trapped in merging magnetic islands can be accelerated by the electric field generated by magnetic island merging and the contraction of magnetic islands. We derive a gyrophase-averaged transport equation for particles experiencing pitch-angle scattering and energization in a super-Alfvénic flowing plasma experiencing multiple small-scale reconnection events. A simpler advection-diffusion transport equation for a nearly isotropic particle distribution is derived. The dominant charged particle energization processes are (1) the electric field induced by quasi-2D magnetic island merging and (2) magnetic island contraction. The magnetic island topology ensures that charged particles are trapped in regions where they experience repeated interactions with the induced electric field or contracting magnetic islands. Steady-state solutions of the isotropic transport equation with only the induced electric field and a fixed source yield a power-law spectrum for the accelerated particles with index α = –(3 + M A )/2, where M A is the Alfvén Mach number. Considering only magnetic island contraction yields power-law-like solutions with index –3(1 + τ c /(8τ diff )), where τ c /τ diff is the ratio of timescales between magnetic island contraction and charged particle diffusion. The general solution is a power-law-like solution with an index that depends on the Alfvén Mach number and the timescale ratio τ diff /τ c . Observed power-law distributions of energetic particles observed in the quiet supersonic solar wind at 1 AU may be a consequence of particle acceleration associated with dissipative small-scale reconnection processes in a turbulent plasma, including the widely reported c –5 (c particle speed) spectra observed by Fisk and Gloeckler

  7. Plasma-enhanced mixing and flameholding in supersonic flow.

    Science.gov (United States)

    Firsov, Alexander; Savelkin, Konstantin V; Yarantsev, Dmitry A; Leonov, Sergey B

    2015-08-13

    The results of experimental study of plasma-based mixing, ignition and flameholding in a supersonic model combustor are presented in the paper. The model combustor has a length of 600 mm and cross section of 72 mm width and 60 mm height. The fuel is directly injected into supersonic airflow (Mach number M=2, static pressure P(st)=160-250 Torr) through wall orifices. Two series of tests are focused on flameholding and mixing correspondingly. In the first series, the near-surface quasi-DC electrical discharge is generated by flush-mounted electrodes at electrical power deposition of W(pl)=3-24 kW. The scope includes parametric study of ignition and flame front dynamics, and comparison of three schemes of plasma generation: the first and the second layouts examine the location of plasma generators upstream and downstream from the fuel injectors. The third pattern follows a novel approach of combined mixing/ignition technique, where the electrical discharge distributes along the fuel jet. The last pattern demonstrates a significant advantage in terms of flameholding limit. In the second series of tests, a long discharge of submicrosecond duration is generated across the flow and along the fuel jet. A gasdynamic instability of thermal cavity developed after a deposition of high-power density in a thin plasma filament promotes the air-fuel mixing. The technique studied in this work has weighty potential for high-speed combustion applications, including cold start/restart of scramjet engines and support of transition regime in dual-mode scramjet and at off-design operation. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  8. Supersonic flows past an obstacle in Yukawa liquids

    Science.gov (United States)

    Charan, Harish; Ganesh, Rajaraman

    2018-04-01

    Shock formation, when a supersonic flow passes a stationary obstacle, is ubiquitous in nature. Considering particles mediating via a Yukawa-type interaction as a prototype for a strongly coupled complex plasma, characterized by coupling strength (Γ, ratio of the average potential to kinetic energy per particle) and screening parameter (κ, ratio of the mean inter-particle distance to the shielding length), we address the fundamental problem of supersonic fluid flow U0, past a stationary obstacle immersed in this strongly coupled system. We here report the results on the bow shocks formed in Yukawa liquids when the liquid flows at speeds larger than the speed of sound in the system. Depending on the values of Mach number MC L=U/0 CL , where CL is the longitudinal speed of sound in the system, the bow shocks are found to be either traveling or localized. We find that for the transonic flows (0.8 ≲ MC L≲ 1.2), the bow shocks travel in the upstream direction opposite to the incoming fluid. The phase velocity of the traveling bow shocks is found to be a non-monotonous function of κ, varying as ∝1 /k1.11 at a fixed value of Γ, and is found to be independent of Γ at a fixed value of κ. It is observed that for the flow values with MC L>1.5 , the shock waves do not travel in the upstream direction but instead form a stationary arc like structure around the obstacle. For the fluid flows with 1 ≲ MC L≲ 2.6 , secondary bow shocks are seen to emerge behind the stationary obstacle which travel in the downstream direction, and the phase velocity of these secondary bow shocks is found to be equal to that of the primary bow shocks.

  9. Potential efficiencies of open- and closed-cycle CO, supersonic, electric-discharge lasers

    Science.gov (United States)

    Monson, D. J.

    1976-01-01

    Computed open- and closed-cycle system efficiencies (laser power output divided by electrical power input) are presented for a CW carbon monoxide, supersonic, electric-discharge laser. Closed-system results include the compressor power required to overcome stagnation pressure losses due to supersonic heat addition and a supersonic diffuser. The paper shows the effect on the system efficiencies of varying several important parameters. These parameters include: gas mixture, gas temperature, gas total temperature, gas density, total discharge energy loading, discharge efficiency, saturated gain coefficient, optical cavity size and location with respect to the discharge, and supersonic diffuser efficiency. Maximum open-cycle efficiency of 80-90% is predicted; the best closed-cycle result is 60-70%.

  10. Efficient solutions to the Euler equations for supersonic flow with embedded subsonic regions

    Science.gov (United States)

    Walters, Robert W.; Dwoyer, Douglas L.

    1987-01-01

    A line Gauss-Seidel (LGS) relaxation algorithm in conjunction with a one-parameter family of upwind discretizations of the Euler equations in two dimensions is described. Convergence of the basic algorithm to the steady state is quadratic for fully supersonic flows and is linear for other flows. This is in contrast to the block alternating direction implicit methods (either central or upwind differenced) and the upwind biased relaxation schemes, all of which converge linearly, independent of the flow regime. Moreover, the algorithm presented herein is easily coupled with methods to detect regions of subsonic flow embedded in supersonic flow. This allows marching by lines in the supersonic regions, converging each line quadratically, and iterating in the subsonic regions, and yields a very efficient iteration strategy. Numerical results are presented for two-dimensional supersonic and transonic flows containing oblique and normal shock waves which confirm the efficiency of the iteration strategy.

  11. Energy-Deposition to Reduce Skin Friction in Supersonic Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has drawn attention to an impending need to improve energy-efficiency in low supersonic (M<~3) platforms. Aerodynamic efficiency is the foundation of...

  12. Energy-Deposition to Reduce Skin Friction in Supersonic Applications, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has drawn attention to an impending need to improve energy-efficiency in low supersonic (M<~3) platforms. Aerodynamic efficiency is the foundation of...

  13. An experimental study of the supersonic, dual, coaxial jets impinging on an inclined flat plate

    International Nuclear Information System (INIS)

    Kim, Jung Bae; Lee, Jun Hee; Woo, Sun Hoon; Kim, Heuy Dong

    2002-01-01

    The impinging supersonic jets have been applied for rocket launching system, thrust control, gas turbine blade cooling, etc. Recently the supersonic, dual, coaxial jets are being extensively used in many diverse fields of industrial processes since they lead to more improved performance, compared with the conventional supersonic jets impinging on an object. In the present study, experimentation is carried out to investigate the supersonic, dual, coaxial jets impinging on an inclined flat plate. A convergent-divergent nozzle with a design Mach number of 2.0 and annular sonic nozzle are used to make the dual, coaxial jet flows. The angle of the impinging flat plate is varied from 30 .deg. to 60 .deg. and the distance between the dual coaxial nozzle and flat plate is also varied. Detailed pressures on the impinging plate are measured to analyze the flow fields, which are also visualized using Schlieren optical method

  14. A Comparison of Prominent LES Combustion Models for Nonpremixed Supersonic Combustion

    Data.gov (United States)

    National Aeronautics and Space Administration — The capability of accurately simulating supersonic combustion is a vital topic for designing and advancing hypersonic air-breathing vehicles. As a consequence, there...

  15. Pulsed molecular beams: A lower limit on pulse duration for fully developed supersonic expansions

    International Nuclear Information System (INIS)

    Saenger, K.L.

    1981-01-01

    We derive an expression for Δt/sub min/, the mimimum pulse duration (''valve open time'') required if a pulsed nozzle is to produce a supersonic beam comparably ''cold'' to that obtained from a continuous source

  16. Sub-scale Direct Connect Supersonic Combustion Facility (Research Cell 18)

    Data.gov (United States)

    Federal Laboratory Consortium — Description: RC18 is a continuous-flow, direct-connect, supersonic-combustion research facility that is capable of simulating flight conditions from Mach 3.0 to Mach...

  17. Zeroth-order flutter prediction for cantilevered plates in supersonic flow

    CSIR Research Space (South Africa)

    Meijer, M-C

    2015-08-01

    Full Text Available An aeroelastic prediction framework in MATLAB with modularity in the quasi-steady aerodynamic methodology is developed. Local piston theory (LPT) is integrated with quasi-steady methods including shock-expansion theory and the Supersonic Hypersonic...

  18. Effect of carrier gas pressure on condensation in a supersonic nozzle

    International Nuclear Information System (INIS)

    Wyslouzil, B.E.; Wilemski, G.; Beals, M.G.; Frish, M.B.

    1994-01-01

    Supersonic nozzle experiments were performed with a fixed water or ethanol vapor pressure and varying amounts of nitrogen to test the hypothesis that carrier gas pressure affects the onset of condensation. Such an effect might occur if nonisothermal nucleation were important under conditions of excess carrier gas in the atmospheric pressure range, as has been suggested by Ford and Clement [J. Phys. A 22, 4007 (1989)]. Although a small increase was observed in the condensation onset temperature as the stagnation pressure was reduced from 3 to 0.5 atm, these changes cannot be attributed to any nonisothermal effects. The pulsed nozzle experiments also exhibited two interesting anomalies: (1) the density profiles for the water and ethanol mixtures were shifted in opposite directions from the dry N 2 profile; (2) a long transient period was required before the nozzle showed good pulse-to-pulse repeatability for condensible vapor mixtures. To theoretically simulate the observed onset behavior, calculations of nucleation and droplet growth in the nozzle were performed that took into account two principal effects of varying the carrier gas pressure: (1) the change in nozzle shape due to boundary layer effects and (2) the variation in the heat capacity of the flowing gas. Energy transfer limitations were neglected in calculating the nucleation rates. The trend of the calculated results matched that of the experimental results very well. Thus, heat capacity and boundary layer effects are sufficient to explain the experimental onset behavior without invoking energy transfer limited nucleation. The conclusions about the rate of nucleation are consistent with those obtained recently using an expansion cloud chamber, but are at odds with results from thermal diffusion cloud chamber measurements

  19. Flow of supersonic jets across flat plates: Implications for ground-level flow from volcanic blasts

    Science.gov (United States)

    Orescanin, Mara M.; Prisco, David; Austin, Joanna M.; Kieffer, Susan W.

    2014-04-01

    We report on laboratory experiments examining the interaction of a jet from an overpressurized reservoir with a canonical ground surface to simulate lateral blasts at volcanoes such as the 1980 blast at Mount St. Helens. These benchmark experiments test the application of supersonic jet models to simulate the flow of volcanic jets over a lateral topography. The internal shock structure of the free jet is modified such that the Mach disk shock is elevated above the surface. In elevation view, the width of the shock is reduced in comparison with a free jet, while in map view the dimensions are comparable. The distance of the Mach disk shock from the vent is in good agreement with free jet data and can be predicted with existing theory. The internal shock structures can interact with and penetrate the boundary layer. In the shock-boundary layer interaction, an oblique shock foot is present in the schlieren images and a distinctive ground signature is evident in surface measurements. The location of the oblique shock foot and the surface demarcation are closely correlated with the Mach disk shock location during reservoir depletion, and therefore, estimates of a ground signature in a zone devastated by a blast can be based on the calculated shock location from free jet theory. These experiments, combined with scaling arguments, suggest that the imprint of the Mach disk shock on the ground should be within the range of 4-9 km at Mount St. Helens depending on assumed reservoir pressure and vent dimensions.

  20. Experimental and Numerical Characterization of a Pulsed Supersonic Uniform Flow for Kinetics and Spectroscopy

    Science.gov (United States)

    Suas-David, Nicolas; Thawoos, Shameemah; Broderick, Bernadette M.; Suits, Arthur

    2017-06-01

    The current CPUF (Chirped Pulse Uniform Flow) and the new UF-CRDS (Uniform Flow Cavity Ring-Down Spectroscopy) setups relie mostly on the production of a good quality supersonic uniform flow. A supersonic uniform flow is produced by expanding a gas through a Laval nozzle - similar to the nozzles used in aeronautics - linked to a vacuum chamber. The expansion is characterized by an isentropic core where constant very low kinetic temperature (down to 20K) and constant density are observed. The relatively large diameter of the isentropic core associated with homogeneous thermodynamic conditions makes it a relevant tool for low temperature spectroscopy. On the other hand, the length along the axis of the flow of this core (could be longer than 50cm) allows kinetic studies which is one of the main interest of this setup (CRESU technique. The formation of a uniform flow requires an extreme accuracy in the design of the shape of the nozzle for a set of defined temperature/density. The design is based on a Matlab program which retrieves the shape of the isentropic core according to the method of characteristics prior to calculate the thickness of the boundary layer. Two different approaches are used to test the viability of a new nozzle derived from the program. First, a computational fluid dynamic software (OpenFOAM) models the distribution of the thermodynamic properties of the expansion. Then, fabricated nozzles using 3-D printing are tested based on Pitot measurements and spectroscopic analyses. I will present comparisons of simulation and measured performance for a range of nozzles. We will see how the high level of accuracy of numerical simulations provides a deeper knowledge of the experimental conditions. J. M. Oldham, C. Abeysekera, J. Joalland, L. N. Zack, K. Prozument, I. R. Sims, G. Barrat Park, R. W. Filed and A. G. Suits, J. Chem. Phys. 141, 154202, (2014). I. Sims, J. L. Queffelec, A. Defrance, C. Rebrion-Rowe, D. Travers, P. Bocherel, B. Rowe, I. W. Smith

  1. Supersonic particle in a low damped complex plasma under microgravity conditions

    Science.gov (United States)

    Zaehringer, E.; Zhdanov, S.; Schwabe, M.; Mohr, D. P.; Knapek, C. A.; Huber, P.; Semenov, I.; Thomas, H. M.

    2018-01-01

    We discuss the diagnostics of a complex plasma cloud recorded in experiments performed in the framework of the Ekoplasma project. A supersonic extra particle is used as a probe of the cloud dynamics. A fine-structured Mach cone behind the supersonic particle is observed. We investigate the spatial and temporal development of the Mach cone with a computer based measurement to determine the speed of sound of the particle cloud. Also time and position dependent characteristics of the velocity field are recorded.

  2. Confinement of plasma along shaped open magnetic fields from the centrifugal force of supersonic plasma rotation.

    Science.gov (United States)

    Teodorescu, C; Young, W C; Swan, G W S; Ellis, R F; Hassam, A B; Romero-Talamas, C A

    2010-08-20

    Interferometric density measurements in plasmas rotating in shaped, open magnetic fields demonstrate strong confinement of plasma parallel to the magnetic field, with density drops of more than a factor of 10. Taken together with spectroscopic measurements of supersonic E × B rotation of sonic Mach 2, these measurements are in agreement with ideal MHD theory which predicts large parallel pressure drops balanced by centrifugal forces in supersonically rotating plasmas.

  3. A Preliminary Evaluation of Supersonic Transport Category Vehicle Operations in the National Airspace System

    Science.gov (United States)

    Underwood, Matthew C.; Guminsky, Michael D.

    2015-01-01

    Several public sector businesses and government agencies, including the National Aeronautics and Space Administration are currently working on solving key technological barriers that must be overcome in order to realize the vision of low-boom supersonic flights conducted over land. However, once these challenges are met, the manner in which this class of aircraft is integrated in the National Airspace System may become a potential constraint due to the significant environmental, efficiency, and economic repercussions that their integration may cause. Background research was performed on historic supersonic operations in the National Airspace System, including both flight deck procedures and air traffic controller procedures. Using this information, an experiment was created to test some of these historic procedures in a current-day, emerging Next Generation Air Transportation System (NextGen) environment and observe the interactions between commercial supersonic transport aircraft and modern-day air traffic. Data was gathered through batch simulations of supersonic commercial transport category aircraft operating in present-day traffic scenarios as a base-lining study to identify the magnitude of the integration problems and begin the exploration of new air traffic management technologies and architectures which will be needed to seamlessly integrate subsonic and supersonic transport aircraft operations. The data gathered include information about encounters between subsonic and supersonic aircraft that may occur when supersonic commercial transport aircraft are integrated into the National Airspace System, as well as flight time data. This initial investigation is being used to inform the creation and refinement of a preliminary Concept of Operations and for the subsequent development of technologies that will enable overland supersonic flight.

  4. Photon Doppler Velocimeter to Measure Entrained Additive Manufactured Bulk Metal Powders in Hot Subsonic and Supersonic Oxygen Gas

    Science.gov (United States)

    Tylka, Jonathan

    2016-01-01

    Parts produced by additive manufacturing, particularly selective laser melting (SLM), have been shown to silt metal particulate even after undergoing stringent precision aerospace cleaning processes (Lowrey 2016). As printed parts are used in oxygen systems with increased pressures, temperatures, and gas velocity, the risk of ignition by particle impact, the most common direct ignition source of metals in oxygen, substantially increases. The White Sands Test Facility (WSTF), in collaboration with Marshall Space Flight Center (MSFC), desires to test the ignitability of SLM metals by particle impact in heated oxygen. The existing test systems rely on gas velocity calculations to infer particle velocity in both subsonic and supersonic particle impact systems. Until now, it was not possible to directly measure particle velocity. To increase the fidelity of planned SLM ignition studies, it is necessary to validate that the Photon Doppler Velocimetry(PDV) test system can accurately measure particle velocity.

  5. A laser-induced-fluorescence visualization study of transverse, sonic fuel injection in a nonreacting supersonic combustor

    Science.gov (United States)

    Mcdaniel, J. C.; Graves, J., Jr.

    1986-01-01

    The present paper reports work which has been conducted in the first phase of a research program which is to provide a data base of spatially-resolved measurements in nonreacting supersonic combustors. In the measurements, a nonintrusive diagnostic technique based on the utilization of laser-induced fluorescence (LIF) is employed. The reported work had the objective to conduct LIF visualization studies of the injection of a simulated fuel into a Mach 2.07 airstream for comparison with corresponding numerical calculations. Attention is given to injection from a single orifice into a constant-area duct, injection from a single orifice behind a rearward-facing step, and injection from staged orifices behind a rearward-facing step.

  6. Non-adiabatic ab initio molecular dynamics of supersonic beam epitaxy of silicon carbide at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Taioli, Simone [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Physics, University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (Italy); Department of Chemistry, University of Bologna, Bologna (Italy); Garberoglio, Giovanni [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Simonucci, Stefano [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Perugia (Italy); Department of Physics, University of Camerino, Camerino (Italy); Beccara, Silvio a [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Physics, University of Trento, Trento (Italy); Aversa, Lucrezia [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Trento (Italy); Nardi, Marco [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Trento (Italy); Institut fuer Physik, Humboldt-Universitaet zu Berlin, Berlin (Germany); Verucchi, Roberto [Institute of Materials for Electronics and Magnetism, FBK-CNR, Trento (Italy); Iannotta, Salvatore [Institute of Materials for Electronics and Magnetism, IMEM-CNR, Parma (Italy); Dapor, Maurizio [Interdisciplinary Laboratory for Computational Science, FBK-Center for Materials and Microsystems and University of Trento, Trento (Italy); Department of Materials Engineering and Industrial Technologies, University of Trento, Trento (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Padova (Italy); and others

    2013-01-28

    In this work, we investigate the processes leading to the room-temperature growth of silicon carbide thin films by supersonic molecular beam epitaxy technique. We present experimental data showing that the collision of fullerene on a silicon surface induces strong chemical-physical perturbations and, for sufficient velocity, disruption of molecular bonds, and cage breaking with formation of nanostructures with different stoichiometric character. We show that in these out-of-equilibrium conditions, it is necessary to go beyond the standard implementations of density functional theory, as ab initio methods based on the Born-Oppenheimer approximation fail to capture the excited-state dynamics. In particular, we analyse the Si-C{sub 60} collision within the non-adiabatic nuclear dynamics framework, where stochastic hops occur between adiabatic surfaces calculated with time-dependent density functional theory. This theoretical description of the C{sub 60} impact on the Si surface is in good agreement with our experimental findings.

  7. Galaxy formation from annihilation-generated supersonic turbulence in the baryon-symmetric big-bang cosmology and the gamma ray background spectrum

    Science.gov (United States)

    Stecker, F. W.; Puget, J. L.

    1972-01-01

    Following the big-bang baryon symmetric cosmology of Omnes, the redshift was calculated to be on the order of 500-600. It is show that, at these redshifts, annihilation pressure at the boundaries between regions of matter and antimatter drives large scale supersonic turbulence which can trigger galaxy formation. This picture is consistent with the gamma-ray background observations discussed previously. Gravitational binding of galaxies then occurs at a redshift of about 70, at which time vortical turbulent velocities of about 3 x 10 to the 7th power cm/s lead to angular momenta for galaxies comparable with measured values.

  8. Climate impact of supersonic air traffic: an approach to optimize a potential future supersonic fleet - results from the EU-project SCENIC

    Science.gov (United States)

    Grewe, V.; Stenke, A.; Ponater, M.; Sausen, R.; Pitari, G.; Iachetti, D.; Rogers, H.; Dessens, O.; Pyle, J.; Isaksen, I. S. A.; Gulstad, L.; Søvde, O. A.; Marizy, C.; Pascuillo, E.

    2007-10-01

    The demand for intercontinental transportation is increasing and people are requesting short travel times, which supersonic air transportation would enable. However, besides noise and sonic boom issues, which we are not referring to in this investigation, emissions from supersonic aircraft are known to alter the atmospheric composition, in particular the ozone layer, and hence affect climate significantly more than subsonic aircraft. Here, we suggest a metric to quantitatively assess different options for supersonic transport with regard to the potential destruction of the ozone layer and climate impacts. Options for fleet size, engine technology (nitrogen oxide emission level), cruising speed, range, and cruising altitude, are analyzed, based on SCENIC emission scenarios for 2050, which underlay the requirements to be as realistic as possible in terms of e.g., economic markets and profitable market penetration. This methodology is based on a number of atmosphere-chemistry and climate models to reduce model dependencies. The model results differ significantly in terms of the response to a replacement of subsonic aircraft by supersonic aircraft, e.g., concerning the ozone impact. However, model differences are smaller when comparing the different options for a supersonic fleet. Those uncertainties were taken into account to make sure that our findings are robust. The base case scenario, where supersonic aircraft get in service in 2015, a first fleet fully operational in 2025 and a second in 2050, leads in our simulations to a near surface temperature increase in 2050 of around 7 mK and with constant emissions afterwards to around 21 mK in 2100. The related total radiative forcing amounts to 22 mWmargin-left: -1.3em; margin-right: .5em; vertical-align: -15%; font-size: .7em; color: #000;">m2 in 2050, with an uncertainty between 9 and 29 mWmargin-left: -1.3em; margin-right: .5em; vertical-align: -15%; font-size: .7em; color: #000;">m2. A reduced supersonic cruise

  9. Climate impact of supersonic air traffic: an approach to optimize a potential future supersonic fleet ─ results from the EU-project SCENIC

    Directory of Open Access Journals (Sweden)

    I.S.A. Isaksen

    2007-10-01

    Full Text Available The demand for intercontinental transportation is increasing and people are requesting short travel times, which supersonic air transportation would enable. However, besides noise and sonic boom issues, which we are not referring to in this investigation, emissions from supersonic aircraft are known to alter the atmospheric composition, in particular the ozone layer, and hence affect climate significantly more than subsonic aircraft. Here, we suggest a metric to quantitatively assess different options for supersonic transport with regard to the potential destruction of the ozone layer and climate impacts. Options for fleet size, engine technology (nitrogen oxide emission level, cruising speed, range, and cruising altitude, are analyzed, based on SCENIC emission scenarios for 2050, which underlay the requirements to be as realistic as possible in terms of e.g., economic markets and profitable market penetration. This methodology is based on a number of atmosphere-chemistry and climate models to reduce model dependencies. The model results differ significantly in terms of the response to a replacement of subsonic aircraft by supersonic aircraft, e.g., concerning the ozone impact. However, model differences are smaller when comparing the different options for a supersonic fleet. Those uncertainties were taken into account to make sure that our findings are robust. The base case scenario, where supersonic aircraft get in service in 2015, a first fleet fully operational in 2025 and a second in 2050, leads in our simulations to a near surface temperature increase in 2050 of around 7 mK and with constant emissions afterwards to around 21 mK in 2100. The related total radiative forcing amounts to 22 mWm2 in 2050, with an uncertainty between 9 and 29 mWm2. A reduced supersonic cruise altitude or speed (from Mach 2 to Mach 1.6 reduces both, climate impact and ozone destruction, by around 40%. An increase in the range of the supersonic aircraft leads to

  10. Burnout calculation

    International Nuclear Information System (INIS)

    Li, D.

    1980-01-01

    Reviewed is the effect of heat flux of different system parameters on critical density in order to give an initial view on the value of several parameters. A thorough analysis of different equations is carried out to calculate burnout is steam-water flows in uniformly heated tubes, annular, and rectangular channels and rod bundles. Effect of heat flux density distribution and flux twisting on burnout and storage determination according to burnout are commended [ru

  11. Reliability calculations

    International Nuclear Information System (INIS)

    Petersen, K.E.

    1986-03-01

    Risk and reliability analysis is increasingly being used in evaluations of plant safety and plant reliability. The analysis can be performed either during the design process or during the operation time, with the purpose to improve the safety or the reliability. Due to plant complexity and safety and availability requirements, sophisticated tools, which are flexible and efficient, are needed. Such tools have been developed in the last 20 years and they have to be continuously refined to meet the growing requirements. Two different areas of application were analysed. In structural reliability probabilistic approaches have been introduced in some cases for the calculation of the reliability of structures or components. A new computer program has been developed based upon numerical integration in several variables. In systems reliability Monte Carlo simulation programs are used especially in analysis of very complex systems. In order to increase the applicability of the programs variance reduction techniques can be applied to speed up the calculation process. Variance reduction techniques have been studied and procedures for implementation of importance sampling are suggested. (author)

  12. Calculator calculus

    CERN Document Server

    McCarty, George

    1982-01-01

    How THIS BOOK DIFFERS This book is about the calculus. What distinguishes it, however, from other books is that it uses the pocket calculator to illustrate the theory. A computation that requires hours of labor when done by hand with tables is quite inappropriate as an example or exercise in a beginning calculus course. But that same computation can become a delicate illustration of the theory when the student does it in seconds on his calculator. t Furthermore, the student's own personal involvement and easy accomplishment give hi~ reassurance and en­ couragement. The machine is like a microscope, and its magnification is a hundred millionfold. We shall be interested in limits, and no stage of numerical approximation proves anything about the limit. However, the derivative of fex) = 67.SgX, for instance, acquires real meaning when a student first appreciates its values as numbers, as limits of 10 100 1000 t A quick example is 1.1 , 1.01 , 1.001 , •••• Another example is t = 0.1, 0.01, in the functio...

  13. Supersonic plasma flow between high latitude conjugate ionospheres

    International Nuclear Information System (INIS)

    Roesler, G.

    1975-01-01

    The polar wind problem has been investigated for closed field lines in situations where one of the two conjugate ionospheric regions is fully illuminated by the sun and the other darkness (solstices at high latitudes). A supersonic flow between hemispheres is possible; the magnetospheric part of this flow must be symmetric with respect to the equator. The daytime fluxes are proportional to the neutral hydrogen density. Fluxes of the order of 10 8 cm -2 sec -1 are only possible with density considerably higher than given by CIRA models. For stationary solutions higher flow speeds are needed on the dark side than provided from the illuminated side. It is concluded that shock waves with upward velocities of about 5 km/sec would form above the dark ionosphere. This implies a reduction by a factor of 3 to 5 of the plasma influx into the dark hemisphere, whereby F-layer densities of only up to 2 x 10 4 cm -3 can be maintained. (orig.) [de

  14. Spectroscopic validation of the supersonic plasma jet model

    International Nuclear Information System (INIS)

    Selezneva, S.E.; Sember, V.; Gravelle, D.V.; Boulos, M.I.

    2002-01-01

    Optical emission spectroscopy is applied to validate numerical simulations of supersonic plasma flow generated by induction torch with a convergent-divergent nozzle. The plasmas exhausting from the discharge tube with the pressure 0.4-1.4 atm. through two nozzle configurations (the outlet Mach number equals 1.5 and 3) into low-pressure (1.8 kPa) chamber are compared. Both modelling and experiments show that the effect of the nozzle geometry on physical properties of plasma jet is significant. The profiles of electron number density obtained from modeling and spectroscopy agree well and show the deviations from local thermodynamic equilibrium. Analysis of intercoupling between different sorts of nonequilibrium processes is performed. The results reveal that the ion recombination is more essential in the nozzle with the higher outlet number than in the nozzle with the lower outlet number. It is demonstrated that in the jets the axial electron temperature is quite low (3000-8000 K). For spectroscopic data interpretation we propose a method based on the definition of two excitation temperatures. We suppose that in mildly under expanded argon jets with frozen ion recombination the electron temperature can be defined by the electronic transitions from level 5p (the energy E=14.5 eV) to level 4p (E=13.116 eV). The obtained results are useful for the optimization of plasma reactors for plasma chemistry and plasma processing applications. (author)

  15. The surface roughness effect on the performance of supersonic ejectors

    Science.gov (United States)

    Brezgin, D. V.; Aronson, K. E.; Mazzelli, F.; Milazzo, A.

    2017-07-01

    The paper presents the numerical simulation results of the surface roughness influence on gas-dynamic processes inside flow parts of a supersonic ejector. These simulations are performed using two commercial CFD solvers (Star- CCM+ and Fluent). The results are compared to each other and verified by a full-scale experiment in terms of global flow parameters (the entrainment ratio: the ratio between secondary to primary mass flow rate - ER hereafter) and local flow parameters distribution (the static pressure distribution along the mixing chamber and diffuser walls). A detailed comparative study of the employed methods and approaches in both CFD packages is carried out in order to estimate the roughness effect on the logarithmic law velocity distribution inside the boundary layer. Influence of the surface roughness is compared with the influence of the backpressure (static pressure at the ejector outlet). It has been found out that increasing either the ejector backpressure or the surface roughness height, the shock position displaces upstream. Moreover, the numerical simulation results of an ejector with rough walls in the both CFD solvers are well quantitatively agreed with each other in terms of the mean ER and well qualitatively agree in terms of the local flow parameters distribution. It is found out that in the case of exceeding the "critical roughness height" for the given boundary conditions and ejector's geometry, the ejector switches to the "off-design" mode and its performance decreases considerably.

  16. Aerodynamics characteristic of axisymmetric surface protuberance in supersonic regime

    KAUST Repository

    Qamar, Adnan; Sanghi, Sanjeev

    2012-01-01

    The present work deals with the problem of an axi-symmetric surface protuberance mounted on a spherical nosed body of revolution. The numerical computations are carried out for laminar supersonic viscous flow for trapezoidal shape axi-symmetric protuberances. A free stream Mach number ranging from 3 to 8 in steps of 1 at a fixed free stream Reynolds number of 1.8x10(4) has been used in the present study. The steady solutions are obtained using a time marching approach. A newly developed Particle Velocity Upwinding (PVU) scheme has been used for the computation. The spatial flow pattern exhibits a strong bow shock in front of the hemispherical nose, which engulfs the entire base body. Near the protuberance, the fluid particle decelerates due to the adverse pressure created by the protuberance and thus the flow separates in front of the protuberance. This point of separation is found to be a function of Mach number and the protuberance shape. A low-pressure expansion region dominates the base region of the obstacle. The reattachment point for the base separation is also a function of Mach number. As the Mach number is increased the reattachment point shifts toward the protuberances base. A weak recompression shock is also seen in the base, which affects the separated zone behind the protuberance. The important design parameters such as skin friction, heat transfer, drag, and surface pressure coefficients are reported extensively.

  17. Thermal effects influencing measurements in a supersonic blowdown wind tunnel

    Directory of Open Access Journals (Sweden)

    Vuković Đorđe S.

    2016-01-01

    Full Text Available During a supersonic run of a blowdown wind tunnel, temperature of air in the test section drops which can affect planned measurements. Adverse thermal effects include variations of the Mach and Reynolds numbers, variation of airspeed, condensation of moisture on the model, change of characteristics of the instrumentation in the model, et cetera. Available data on thermal effects on instrumentation are pertaining primarily to long-run-duration wind tunnel facilities. In order to characterize such influences on instrumentation in the models, in short-run-duration blowdown wind tunnels, temperature measurements were made in the wing-panel-balance and main-balance spaces of two wind tunnel models tested in the T-38 wind tunnel. The measurements showed that model-interior temperature in a run increased at the beginning of the run, followed by a slower drop and, at the end of the run, by a large temperature drop. Panel-force balance was affected much more than the main balance. Ways of reducing the unwelcome thermal effects by instrumentation design and test planning are discussed.

  18. Role of coherent structures in supersonic impinging jetsa)

    Science.gov (United States)

    Kumar, Rajan; Wiley, Alex; Venkatakrishnan, L.; Alvi, Farrukh

    2013-07-01

    This paper describes the results of a study examining the flow field and acoustic characteristics of a Mach 1.5 ideally expanded supersonic jet impinging on a flat surface and its control using steady microjets. Emphasis is placed on two conditions of nozzle to plate distances (h/d), of which one corresponds to where the microjet based active flow control is very effective in reducing flow unsteadiness and near-field acoustics and the other has minimal effectiveness. Measurements include unsteady pressures, nearfield acoustics using microphone and particle image velocimetry. The nearfield noise and unsteady pressure spectra at both h/d show discrete high amplitude impinging tones, which in one case (h/d = 4) are significantly reduced with control but in the other case (h/d = 4.5) remain unaffected. The particle image velocimetry measurements, both time-averaged and phase-averaged, were used to better understand the basic characteristics of the impinging jet flow field especially the role of coherent vortical structures in the noise generation and control. The results show that the flow field corresponding to the case of least control effectiveness comprise well defined, coherent, and symmetrical vortical structures and may require higher levels of microjet pressure supply for noise suppression when compared to the flow field more responsive to control (h/d = 4) which shows less organized, competing (symmetrical and helical) instabilities.

  19. Trend of supersonic aircraft engine. Choonsokukiyo engine no doko

    Energy Technology Data Exchange (ETDEWEB)

    Yashima, S [Ishikawajima-Harima Heavy Industries, Co. Ltd., Tokyo (Japan)

    1994-05-01

    The present paper explained the R and D trend of supersonic aircraft engine in Europe, USA and Japan. Taking the high speed flight resistance into consideration, the engine must be characterized by its high exhaust gas speed and high specific thrust (ratio of thrust to the airflow rate) to secure strong thrust by a low airflow rate. Therefore, the turbojet is appropriate. However to reduce the fuel consumption during the cruising flight, the turbofan is normally used with a low by-pass ratio of 0.2 to 0.9. The thrust-to-weight ratio (thrust per unit weight) of low by-pass ratio turbofan engine equipped with afterburner is 7 to 8 in case of stronger thrust than 70kN. Its target value of development is 10. The specific thrust which is a performance parameter of engine exceeds 120s for the fighter engine and is about 30s for the passenger plane engine. The turbine inlet temperature is 2073K at the stage of element research. The overall pressure ratio ranges from 25 to 30. The reheating turbofan engine experimentally built for the research in Japan is 34kN in thrust and 7 in thrust-to-weight ratio. 8 refs., 9 figs.

  20. Preliminary Design Optimization For A Supersonic Turbine For Rocket Propulsion

    Science.gov (United States)

    Papila, Nilay; Shyy, Wei; Griffin, Lisa; Huber, Frank; Tran, Ken; McConnaughey, Helen (Technical Monitor)

    2000-01-01

    In this study, we present a method for optimizing, at the preliminary design level, a supersonic turbine for rocket propulsion system application. Single-, two- and three-stage turbines are considered with the number of design variables increasing from 6 to 11 then to 15, in accordance with the number of stages. Due to its global nature and flexibility in handling different types of information, the response surface methodology (RSM) is applied in the present study. A major goal of the present Optimization effort is to balance the desire of maximizing aerodynamic performance and minimizing weight. To ascertain required predictive capability of the RSM, a two-level domain refinement approach has been adopted. The accuracy of the predicted optimal design points based on this strategy is shown to he satisfactory. Our investigation indicates that the efficiency rises quickly from single stage to 2 stages but that the increase is much less pronounced with 3 stages. A 1-stage turbine performs poorly under the engine balance boundary condition. A portion of fluid kinetic energy is lost at the turbine discharge of the 1-stage design due to high stage pressure ratio and high-energy content, mostly hydrogen, of the working fluid. Regarding the optimization technique, issues related to the design of experiments (DOE) has also been investigated. It is demonstrated that the criteria for selecting the data base exhibit significant impact on the efficiency and effectiveness of the construction of the response surface.

  1. Diagnosis for the interaction of supersonic molecular beam with plasma

    International Nuclear Information System (INIS)

    Yao Lianghua; Feng Beibing; Feng Zhen; Luo Junlin; Dong Jiafu; Yan Longwen; Hong Wenyu

    2001-01-01

    Supersonic Molecular Beam Injection (SMBI) is a new fuelling method for Tokamaks and has recently been improved to enhance the flux of the beam and to make a survey of the cluster effect within the beam. There are a series of new phenomena, which implicate the interaction of the beam (including clusters) with the toroidal plasma of HL-1M Tokamak. The H α signals from the edge show a regular variation around the torus. Around the injection port, the edge H α signals are positive rectangular wave, which is consistent with that of the injection beam pulses. The edge electron temperature, measured with movable Langmuir probes, decreases by an order of magnitude and the density increases by an order of magnitude. H α emission at the beam injection port, measured with CCD camera at an angle of 13.4 degrees to the SMBI line, shows many separate peaks within the contour plot. These peaks may show the strong emission produced by the interaction of the hydrogen clusters with the plasma. Hydrogen clusters may be produced in the beam according to the empirical scaling (Hagena) law of clustering onset, Γ* = kd 0.85 P 0 /T 0 2.29 , here d is the nozzle diameter in μm, P 0 the stagnation pressure in mbar, T 0 the source temperature in K, and k is a constant related to the gas species. If Γ* > 100, clusters will be formed. In present experiment Γ* is about 127

  2. Shear layer characteristics of supersonic free and impinging jets

    Science.gov (United States)

    Davis, T. B.; Kumar, R.

    2015-09-01

    The initial shear layer characteristics of a jet play an important role in the initiation and development of instabilities and hence radiated noise. Particle image velocimetry has been utilized to study the initial shear layer development of supersonic free and impinging jets. Microjet control employed to reduce flow unsteadiness and jet noise appears to affect the development of the shear layer, particularly near the nozzle exit. Velocity field measurements near the nozzle exit show that the initially thin, uncontrolled shear layer develops at a constant rate while microjet control is characterized by a rapid nonlinear thickening that asymptotes downstream. The shear layer linear growth rate with microjet control, in both the free and the impinging jet, is diminished. In addition, the thickened shear layer with control leads to a reduction in azimuthal vorticity for both free and impinging jets. Linear stability theory is used to compute unstable growth rates and convection velocities of the resultant velocity profiles. The results show that while the convection velocity is largely unaffected, the unstable growth rates are significantly reduced over all frequencies with microjet injection. For the case of the impinging jet, microjet control leads to near elimination of the impingement tones and an appreciable reduction in broadband levels. Similarly, for the free jet, significant reduction in overall sound pressure levels in the peak radiation direction is observed.

  3. The manipulation of an unstarting supersonic flow by plasma actuator

    International Nuclear Information System (INIS)

    Im, S; Cappelli, M A; Do, H

    2012-01-01

    The manipulation of an unstarting supersonic flow is demonstrated using a dielectric barrier discharge (DBD). Experiments are carried out in a Mach 4.7 model inlet flow. Flow features, such as boundary layers and shockwaves at low freestream static pressure (1 kPa) and temperature (60 K) are visualized with Rayleigh scattering from condensed CO 2 particles. Flow unstart, initiated by mass injection, is studied for three model inlet flow configurations, distinguished by the initial conditions (untripped or tripped, plasma actuated or not) of the boundary layers. Unstart in the presence of thick, tripped boundary layers is characterized by the formation of an oblique unstart shock just upstream of a separating and propagating boundary layer. The presence of plasma actuation of this tripped boundary layer seems to arrest the boundary layer separation and leads to the formation of a quasi-stationary pseudo-shock, delaying unstart. The flow generated with DBD actuation is more characteristic of what is seen when unstart is generated in a model flow in which thin boundary layers grow naturally. Planar laser Rayleigh scattering visualizations suggest that the DBD actuation thins the tripped boundary layer over the exposed electrode region.

  4. Flight tests of a supersonic natural laminar flow airfoil

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  5. Effects of streamwise vortex breakdown on supersonic combustion.

    Science.gov (United States)

    Hiejima, Toshihiko

    2016-04-01

    This paper presents a numerical simulation study of the combustion structure of streamwise vortex breakdown at Mach number 2.48. Hydrogen fuel is injected into a combustor at sonic speed from the rear of a hypermixer strut that can generate streamwise vortices. The results show that the burning behavior is enhanced at the points of the shock waves that are incident on the vortex and therefore the vortex breakdown in the subsonic region occurs due to combustion. The breakdown domain in the mainstream is found to form a flame-holding region suited to combustion and to lead to a stable combustion field with detached flames. In this way, streamwise vortex breakdown has an essential role in combustion enhancement and the formation of flames that hold under supersonic inflow conditions. Finally, the combustion property defined here is shown to coincide with the produced-water mass flow. This property shows that the amount of combustion is saturated at equivalence ratios over 0.4, although there is a slight increase beyond 1.

  6. Supersonics/Airport Noise Plan: An Evolutionary Roadmap

    Science.gov (United States)

    Bridges, James

    2011-01-01

    This presentation discusses the Plan for the Airport Noise Tech Challenge Area of the Supersonics Project. It is given in the context of strategic planning exercises being done in other Projects to show the strategic aspects of the Airport Noise plan rather than detailed task lists. The essence of this strategic view is the decomposition of the research plan by Concept and by Tools. Tools (computational, experimental) is the description of the plan that resources (such as researchers) most readily identify with, while Concepts (here noise reduction technologies or aircraft configurations) is the aspects that project management and outside reviewers most appreciate as deliverables and milestones. By carefully cross-linking these so that Concepts are addressed sequentially (roughly one after another) by researchers developing/applying their Tools simultaneously (in parallel with one another), the researchers can deliver milestones at a reasonable pace while doing the longer-term development that most Tools in the aeroacoustics science require. An example of this simultaneous application of tools was given for the Concept of High Aspect Ratio Nozzles. The presentation concluded with a few ideas on how this strategic view could be applied to the Subsonic Fixed Wing Project's Quiet Aircraft Tech Challenge Area as it works through its current roadmapping exercise.

  7. Robust optimization of supersonic ORC nozzle guide vanes

    Science.gov (United States)

    Bufi, Elio A.; Cinnella, Paola

    2017-03-01

    An efficient Robust Optimization (RO) strategy is developed for the design of 2D supersonic Organic Rankine Cycle turbine expanders. The dense gas effects are not-negligible for this application and they are taken into account describing the thermodynamics by means of the Peng-Robinson-Stryjek-Vera equation of state. The design methodology combines an Uncertainty Quantification (UQ) loop based on a Bayesian kriging model of the system response to the uncertain parameters, used to approximate statistics (mean and variance) of the uncertain system output, a CFD solver, and a multi-objective non-dominated sorting algorithm (NSGA), also based on a Kriging surrogate of the multi-objective fitness function, along with an adaptive infill strategy for surrogate enrichment at each generation of the NSGA. The objective functions are the average and variance of the isentropic efficiency. The blade shape is parametrized by means of a Free Form Deformation (FFD) approach. The robust optimal blades are compared to the baseline design (based on the Method of Characteristics) and to a blade obtained by means of a deterministic CFD-based optimization.

  8. LPWA using supersonic gas jet with tailored density profile

    Science.gov (United States)

    Kononenko, O.; Bohlen, S.; Dale, J.; D'Arcy, R.; Dinter, M.; Erbe, J. H.; Indorf, G.; di Lucchio, L.; Goldberg, L.; Gruse, J. N.; Karstensen, S.; Libov, V.; Ludwig, K.; Martinez de La Ossa, A.; Marutzky, F.; Niroula, A.; Osterhoff, J.; Quast, M.; Schaper, L.; Schwinkendorf, J.-P.; Streeter, M.; Tauscher, G.; Weichert, S.; Palmer, C.; Horbatiuk, Taras

    2016-10-01

    Laser driven plasma wakefield accelerators have been explored as a potential compact, reproducible source of relativistic electron bunches, utilising an electric field of many GV/m. Control over injection of electrons into the wakefield is of crucial importance in producing stable, mono-energetic electron bunches. Density tailoring of the target, to control the acceleration process, can also be used to improve the quality of the bunch. By using gas jets to provide tailored targets it is possible to provide good access for plasma diagnostics while also producing sharp density gradients for density down-ramp injection. OpenFOAM hydrodynamic simulations were used to investigate the possibility of producing tailored density targets in a supersonic gas jet. Particle-in-cell simulations of the resulting density profiles modelled the effect of the tailored density on the properties of the accelerated electron bunch. Here, we present the simulation results together with preliminary experimental measurements of electron and x-ray properties from LPWA experiments using gas jet targets and a 25 TW, 25 fs Ti:Sa laser system at DESY.

  9. Experimental observations of a complex, supersonic nozzle concept

    Science.gov (United States)

    Magstadt, Andrew; Berry, Matthew; Glauser, Mark; Ruscher, Christopher; Gogineni, Sivaram; Kiel, Barry; Skytop Turbulence Labs, Syracuse University Team; Spectral Energies, LLC. Team; Air Force Research Laboratory Team

    2015-11-01

    A complex nozzle concept, which fuses multiple canonical flows together, has been experimentally investigated via pressure, schlieren and PIV in the anechoic chamber at Syracuse University. Motivated by future engine designs of high-performance aircraft, the rectangular, supersonic jet under investigation has a single plane of symmetry, an additional shear layer (referred to as a wall jet) and an aft deck representative of airframe integration. Operating near a Reynolds number of 3 ×106 , the nozzle architecture creates an intricate flow field comprised of high turbulence levels, shocks, shear & boundary layers, and powerful corner vortices. Current data suggest that the wall jet, which is an order of magnitude less energetic than the core, has significant control authority over the acoustic power through some non-linear process. As sound is a direct product of turbulence, experimental and analytical efforts further explore this interesting phenomenon associated with the turbulent flow. The authors acknowledge the funding source, a SBIR Phase II project with Spectral Energies, LLC. and AFRL turbine engine branch under the direction of Dr. Barry Kiel.

  10. General-purpose software for science technology calculation

    International Nuclear Information System (INIS)

    Aikawa, Hiroshi

    1999-01-01

    We have developed many general-purpose softwares for parallel processing of science technology calculation. This paper reported six softwares such as STA (Seamless Thinking Aid) basic soft, parallel numerical computation library, grid formation software for parallel computer, real-time visualizing system, parallel benchmark test system and object-oriented parallel programing method. STA is a user interface software to perform a total environment for parallel programing, a network computing environment for various parallel computers and a desktop computing environment via Web. Some examples using the above softwares are explained. One of them is a simultaneous parallel calculation of both analysis of flow and structure of supersonic transport to design of them. The other is various kinds of computer parallel calculations for nuclear fusion reaction such as a molecular dynamic calculation and a calculation of reactor structure and fluid. These softs are opened to the public by the home page {http://guide.tokai.jaeri.go.jp/ccse/}. (S.Y.)

  11. Active Control Strategies to Optimize Supersonic Fuel-Air Mixing for Combustion Associated with Fully Modulated Transverse Jet in Cross Flow

    National Research Council Canada - National Science Library

    Ghenai, C; Philippidis, G. P; Lin, C. X

    2005-01-01

    ... (subsonic- supersonic) combustion studies. A high-speed imaging system was used for the visualization of pure liquid jet, aerated liquid jet and pulsed aerated jet injection into a supersonic cross flow at Mach number 1.5...

  12. Reliability Calculations

    DEFF Research Database (Denmark)

    Petersen, Kurt Erling

    1986-01-01

    Risk and reliability analysis is increasingly being used in evaluations of plant safety and plant reliability. The analysis can be performed either during the design process or during the operation time, with the purpose to improve the safety or the reliability. Due to plant complexity and safety...... and availability requirements, sophisticated tools, which are flexible and efficient, are needed. Such tools have been developed in the last 20 years and they have to be continuously refined to meet the growing requirements. Two different areas of application were analysed. In structural reliability probabilistic...... approaches have been introduced in some cases for the calculation of the reliability of structures or components. A new computer program has been developed based upon numerical integration in several variables. In systems reliability Monte Carlo simulation programs are used especially in analysis of very...

  13. Fundamental Aeronautics Program: Overview of Project Work in Supersonic Cruise Efficiency

    Science.gov (United States)

    Castner, Raymond

    2011-01-01

    The Supersonics Project, part of NASA?s Fundamental Aeronautics Program, contains a number of technical challenge areas which include sonic boom community response, airport noise, high altitude emissions, cruise efficiency, light weight durable engines/airframes, and integrated multi-discipline system design. This presentation provides an overview of the current (2011) activities in the supersonic cruise efficiency technical challenge, and is focused specifically on propulsion technologies. The intent is to develop and validate high-performance supersonic inlet and nozzle technologies. Additional work is planned for design and analysis tools for highly-integrated low-noise, low-boom applications. If successful, the payoffs include improved technologies and tools for optimized propulsion systems, propulsion technologies for a minimized sonic boom signature, and a balanced approach to meeting efficiency and community noise goals. In this propulsion area, the work is divided into advanced supersonic inlet concepts, advanced supersonic nozzle concepts, low fidelity computational tool development, high fidelity computational tools, and improved sensors and measurement capability. The current work in each area is summarized.

  14. Fundamental Aeronautics Program: Overview of Propulsion Work in the Supersonic Cruise Efficiency Technical Challenge

    Science.gov (United States)

    Castner, Ray

    2012-01-01

    The Supersonics Project, part of NASA's Fundamental Aeronautics Program, contains a number of technical challenge areas which include sonic boom community response, airport noise, high altitude emissions, cruise efficiency, light weight durable engines/airframes, and integrated multi-discipline system design. This presentation provides an overview of the current (2012) activities in the supersonic cruise efficiency technical challenge, and is focused specifically on propulsion technologies. The intent is to develop and validate high-performance supersonic inlet and nozzle technologies. Additional work is planned for design and analysis tools for highly-integrated low-noise, low-boom applications. If successful, the payoffs include improved technologies and tools for optimized propulsion systems, propulsion technologies for a minimized sonic boom signature, and a balanced approach to meeting efficiency and community noise goals. In this propulsion area, the work is divided into advanced supersonic inlet concepts, advanced supersonic nozzle concepts, low fidelity computational tool development, high fidelity computational tools, and improved sensors and measurement capability. The current work in each area is summarized.

  15. Performance of a CW double electric discharge for supersonic CO lasers

    Science.gov (United States)

    Stanton, A. C.; Hanson, R. K.; Mitchner, M.

    1980-01-01

    The results of an experimental investigation of a CW double discharge in supersonic CO mixtures are reported. Stable discharges in CO/N2 and CO/Ar mixtures, with a maximum energy loading of 0.5 eV/CO molecule, were achieved in a small-scale continuous-flow supersonic channel. Detailed measurements of the discharge characteristics were performed, including electrostatic probe measurements of floating potential and electron number density and spectroscopic measurements of the CO vibrational population distributions. The results of these measurements indicate that the vibrational excitation efficiency of the discharge is approximately 60%, for moderate levels of main discharge current. These experiments, on a small scale, demonstrate that the double-discharge scheme provides adequate vibrational energy loading for efficient CO laser operation under CW supersonic flow conditions.

  16. High Efficiency Low Cost CO2 Compression Using Supersonic Shock Wave Technology

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J; Aarnio, M; Grosvenor, A; Taylor, D; Bucher, J

    2010-12-31

    Development and testing results from a supersonic compressor are presented. The compressor achieved record pressure ratio for a fully-supersonic stage and successfully demonstrated the technology potential. Several tasks were performed in compliance with the DOE award objectives. A high-pressure ratio compressor was retrofitted to improve rotordynamics behavior and successfully tested. An outside review panel confirmed test results and design approach. A computational fluid dynamics code used to analyze the Ramgen supersonic flowpath was extensively and successfully modified to improve use on high-performance computing platforms. A comprehensive R&D implementation plan was developed and used to lay the groundwork for a future full-scale compressor demonstration. Conceptual design for a CO2 demonstration compressor was developed and reviewed.

  17. Design and Testing of CO2 Compression Using Supersonic Shock Wave Technology

    Energy Technology Data Exchange (ETDEWEB)

    Koopman, Aaron [Seattle Technology Center, Bellevue, WA (United States)

    2015-06-01

    This report summarizes work performed by Ramgen and subcontractors in pursuit of the design and construction of a 10 MW supersonic CO2 compressor and supporting facility. The compressor will demonstrate application of Ramgen’s supersonic compression technology at an industrial scale using CO2 in a closed-loop. The report includes details of early feasibility studies, CFD validation and comparison to experimental data, static test experimental results, compressor and facility design and analyses, and development of aerodynamic tools. A summary of Ramgen's ISC Engine program activity is also included. This program will demonstrate the adaptation of Ramgen's supersonic compression and advanced vortex combustion technology to result in a highly efficient and cost effective alternative to traditional gas turbine engines. The build out of a 1.5 MW test facility to support the engine and associated subcomponent test program is summarized.

  18. Manufacturing of a micro-tungsten carbide electrode using a supersonic-aided electrolysis process

    International Nuclear Information System (INIS)

    Weng, Feng-Tsai; Ho, Chi-Ting

    2008-01-01

    In this study, a novel micromachining technology for fabricating micro parts was described. The original diameter of a tungsten carbide rod was 3 mm, and it was first processed to a rod with a diameter of 50 µm by a precision-grinding process. It could then be machined to the desired diameter by a supersonic-aided electrolysis process. A high-aspect ratio of the micro-tungsten carbide rod was easily obtained by this process. The surface roughness of the sample that was processed by electrolysis with supersonic-aided agitation was compared with that of the sample obtained without agitation. The machined surface of the sample was smooth, and the reason may be that ionized particles in the anode could be removed by supersonic-aided agitation during the electrolysis process. A microelectrode with a tip of approximately 1 µm could be obtained by this process. (technical note)

  19. Features of the laminar-turbulent transition in supersonic axisymmetric microjets

    Science.gov (United States)

    Maslov, A. A.; Aniskin, V. M.; Mironov, S. G.

    2016-10-01

    In this paper, a supersonic core length of microjets is studied in terms of laminar-turbulent transition in the microjet mixing layer. Previously, it was discovered that this transition has a determining influence on the supersonic core length. A possibility of simulation of microjet flows is estimated through the use of Reynolds number computed by the nozzle diameter and the nozzle exit gas parameters. These experimental data were obtained using Pitot tube when the jets escaping from the nozzle of 0.6 mm into the low-pressure space. This experiment made it possible to achieve a large jet pressure ratio when the Reynolds number values were low which specify the microjets' behavior. The supersonic core length, phase of the laminar-turbulent transition and flow characteristics in the space are obtained. Such an approach provides simulation of the characteristics of microjets and macrojets, and also explains preliminary proposition and some data obtained for microjets.

  20. Flutter analysis of hybrid metal-composite low aspect ratio trapezoidal wings in supersonic flow

    Directory of Open Access Journals (Sweden)

    Shokrollahi Saeed

    2017-02-01

    Full Text Available An effective 3D supersonic Mach box approach in combination with non-classical hybrid metal-composite plate theory has been used to investigate flutter boundaries of trapezoidal low aspect ratio wings. The wing structure is composed of two main components including aluminum material (in-board section and laminated composite material (out-board section. A global Ritz method is used with simple polynomials being employed as the trial functions. The most important objective of the present research is to study the effect of composite to metal proportion of hybrid wing structure on flutter boundaries in low supersonic regime. In addition, the effect of some important geometrical parameters such as sweep angle, taper ratio and aspect ratio on flutter boundaries were studied. The results obtained by present approach for special cases like pure metallic wings and results for high supersonic regime based on piston theory show a good agreement with those obtained by other investigators.

  1. Advanced supersonic propulsion study, phases 3 and 4. [variable cycle engines

    Science.gov (United States)

    Allan, R. D.; Joy, W.

    1977-01-01

    An evaluation of various advanced propulsion concepts for supersonic cruise aircraft resulted in the identification of the double-bypass variable cycle engine as the most promising concept. This engine design utilizes special variable geometry components and an annular exhaust nozzle to provide high take-off thrust and low jet noise. The engine also provides good performance at both supersonic cruise and subsonic cruise. Emission characteristics are excellent. The advanced technology double-bypass variable cycle engine offers an improvement in aircraft range performance relative to earlier supersonic jet engine designs and yet at a lower level of engine noise. Research and technology programs required in certain design areas for this engine concept to realize its potential benefits include refined parametric analysis of selected variable cycle engines, screening of additional unconventional concepts, and engine preliminary design studies. Required critical technology programs are summarized.

  2. Hydrogen tube vehicle for supersonic transport: Analysis of the concept

    Energy Technology Data Exchange (ETDEWEB)

    Miller, A.R. [Vehicle Projects LLC and Supersonic Tube Vehicle LLC, 621 17th Street, Suite 2131, Denver, CO 80293 (United States)

    2008-04-15

    I propose and analyze a concept vehicle that operates in a hydrogen atmosphere contained within a tube, or pipeline, and because of the high speed of sound in hydrogen, it delays the onset of the sound barrier. Mach 1.2 in air corresponds to only Mach 0.32 in hydrogen. The proposed vehicle, a cross between a train and an airplane, is multi-articulated, runs on a guideway, is propelled by propfans, and flies on a hydrogen aerostatic fluid film. Vehicle power is provided by onboard hydrogen-oxygen fuel cells. Hydrogen fuel is taken from the tube itself, liquid oxygen (LOX) is carried onboard, and the product water is collected and stored until the end of a run. Thus, unlike conventional vehicles, it breathes its fuel, stores its oxidant, and its weight increases during operation. Taking hydrogen fuel from the tube solves the problem of vehicular hydrogen storage, a major challenge of contemporary hydrogen fuel-cell vehicles. The foundation of the feasibility analysis is extrapolation of aerodynamic properties of a mid-sized turboprop airliner, the Bombardier Dash 8 Q400 trademark. Based on the aerodynamic analysis, I estimate that the hydrogen tube vehicle would require 2.0 MW of power to run at 1500 km/h, which is supersonic with respect to air. It would require 2.64 h to travel from New York City to Los Angeles, consuming 2330 L of onboard LOX and producing 2990 L of liquid water during the trip. Part of the feasibility analysis shows that it is possible to package the corresponding fuel-cell stacks, LOX systems, and water holding tanks in the tube vehicle. The greatest technical challenge is levitation by aerostatic hydrogen bearings. Risk of fire or detonation within the tube, similar to that of existing large natural-gas pipelines, is expected to be manageable and acceptable. (author)

  3. Factors Influencing Pitot Probe Centerline Displacement in a Turbulent Supersonic Boundary Layer

    Science.gov (United States)

    Grosser, Wendy I.

    1997-01-01

    When a total pressure probe is used for measuring flows with transverse total pressure gradients, a displacement of the effective center of the probe is observed (designated Delta). While this phenomenon is well documented in incompressible flow and supersonic laminar flow, there is insufficient information concerning supersonic turbulent flow. In this study, three NASA Lewis Research Center Supersonic Wind Tunnels (SWT's) were used to investigate pitot probe centerline displacement in supersonic turbulent boundary layers. The relationship between test conditions and pitot probe centerline displacement error was to be determined. For this investigation, ten circular probes with diameter-to-boundary layer ratios (D/delta) ranging from 0.015 to 0.256 were tested in the 10 ft x 10 ft SWT, the 15 cm x 15 cm SWT, and the 1 ft x 1 ft SWT. Reynolds numbers of 4.27 x 10(exp 6)/m, 6.00 x 10(exp 6)/in, 10.33 x 10(exp 6)/in, and 16.9 x 10(exp 6)/m were tested at nominal Mach numbers of 2.0 and 2.5. Boundary layer thicknesses for the three tunnels were approximately 200 mm, 13 mm, and 30 mm, respectively. Initial results indicate that boundary layer thickness, delta, and probe diameter, D/delta play a minimal role in pitot probe centerline offset error, Delta/D. It appears that the Mach gradient, dM/dy, is an important factor, though the exact relationship has not yet been determined. More data is needed to fill the map before a conclusion can be drawn with any certainty. This research provides valuable supersonic, turbulent boundary layer data from three supersonic wind tunnels with three very different boundary layers. It will prove a valuable stepping stone for future research into the factors influencing pitot probe centerline offset error.

  4. Identification of novel synthetic organic compounds with supersonic gas chromatography-mass spectrometry.

    Science.gov (United States)

    Fialkov, Alexander B; Amirav, Aviv

    2004-11-26

    Several novel synthetic organic compounds were successfully analyzed with a unique type of GC-MS titled Supersonic GC-MS following a failure in their analysis with standard GC-MS. Supersonic GC-MS is based on interfacing GC and MS with a supersonic molecular beam (SMB) and on electron ionization of sample compounds as vibrationally cold molecules while in the SMB, or by cluster chemical ionization. The analyses of novel synthetic organic compounds significantly benefited from the extended range of compounds amenable to analyses with the Supersonic GC-MS. The Supersonic GC-MS enabled the analysis of thermally labile compounds that usually degrade in the GC injector, column and/or ion source. Due to the high carrier gas flow rate at the injector liner and column these compounds eluted without degradation at significantly lower elution temperatures and the use of fly-through EI ion source eliminated any sample degradation at the ion source. The cold EI feature of providing trustworthy enhanced molecular ion (M+), complemented by its optional further confirmation with cluster CI was highly valued by the synthetic organic chemists that were served by the Supersonic GC-MS. Furthermore, the provision of extended mass spectral structural, isomer and isotope information combined with short (a few minutes) GC-MS analysis times also proved beneficial for the analysis of unknown synthetic organic compounds. As a result, the synthetic organic chemists were provided with both qualitative and quantitative data on the composition of their synthetic mixture, and could better follow the path of their synthetic chemistry. Ten cases of such analyses are demonstrated in figures and discussed.

  5. Advanced Concept Studies for Supersonic Commercial Transports Entering Service in the 2018-2020 Period Phase 2

    Science.gov (United States)

    Morgenstern, John; Buonanno, Michael; Yao, Jixian; Murugappan, Mugam; Paliath, Umesh; Cheung, Lawrence; Malcevic, Ivan; Ramakrishnan, Kishore; Pastouchenko, Nikolai; Wood, Trevor; hide

    2015-01-01

    Lockheed Martin Aeronautics Company (LM), working in conjunction with General Electric Global Research (GE GR) and Stanford University, executed a 19 month program responsive to the NASA sponsored "N+2 Supersonic Validation: Advanced Concept Studies for Supersonic Commercial Transports Entering Service in the 2018-2020 Period" contract. The key technical objective of this effort was to validate integrated airframe and propulsion technologies and design methodologies necessary to realize a supersonic vehicle capable of meeting the N+2 environmental and performance goals. The N+2 program is aligned with NASA's Supersonic Project and is focused on providing system level solutions capable of overcoming the efficiency, environmental, and performance barriers to practical supersonic flight. The N+2 environmental and performance goals are outlined in the technical paper, AIAA-2014-2138 (Ref. 1) along with the validated N+2 Phase 2 results. Our Phase 2 efforts built upon our Phase 1 studies (Ref. 2) and successfully demonstrated the ability to design and test realistic configurations capable of shaped sonic booms over the width of the sonic boom carpet. Developing a shaped boom configuration capable of meeting the N+2 shaped boom targets is a key goal for the N+2 program. During the LM Phase 1 effort, LM successfully designed and tested a shaped boom trijet configuration (1021) capable of achieving 85 PLdB under track (forward and aft shock) and up to 28 deg off-track at Mach 1.6. In Phase 2 we developed a refined configuration (1044-2) that extended the under 85 PLdB sonic boom level over the entire carpet of 52 deg off-track at a cruise Mach number of 1.7. Further, the loudness level of the configuration throughout operational conditions calculates to an average of 79 PLdB. These calculations rely on propagation employing Burger's (sBOOM) rounding methodology, and there are indications that the configuration average loudness would actually be 75 PLdB. We also added

  6. An atomic coilgun: using pulsed magnetic fields to slow a supersonic beam

    International Nuclear Information System (INIS)

    Narevicius, E; Parthey, C G; Libson, A; Narevicius, J; Chavez, I; Even, U; Raizen, M G

    2007-01-01

    We report the experimental demonstration of a novel method to slow atoms and molecules with permanent magnetic moments using pulsed magnetic fields. In our experiments, we observe the slowing of a supersonic beam of metastable neon from 461.0 ± 7.7 to 403 ± 16 m s -1 in 18 stages, where the slowed peak is clearly separated from the initial distribution. This method has broad applications as it may easily be generalized, using seeding and entrainment into supersonic beams, to all paramagnetic atoms and molecules

  7. Design and Testing of CO2 Compression Using Supersonic Shockware Technology

    Energy Technology Data Exchange (ETDEWEB)

    Joe Williams; Michael Aarnio; Kirk Lupkes; Sabri Deniz

    2010-08-31

    Documentation of work performed by Ramgen and subcontractors in pursuit of design and construction of a 10 MW supersonic CO{sub 2} compressor and supporting facility. The compressor will demonstrate application of Ramgen's supersonic compression technology at an industrial scale using CO{sub 2} in a closed-loop. The report includes details of early feasibility studies, CFD validation and comparison to experimental data, static test experimental results, compressor and facility design and analyses, and development of aero tools.

  8. Static Aeroelastic Deformation Effects in Preliminary Wind-tunnel Tests of Silent Supersonic Technology Demonstrator

    OpenAIRE

    Makino, Yoshikazu; Ohira, Keisuke; Makimoto, Takuya; Mitomo, Toshiteru; 牧野, 好和; 大平, 啓介; 牧本, 卓也; 三友, 俊輝

    2011-01-01

    Effects of static aeroelastic deformation of a wind-tunnel test model on the aerodynamic characteristics are discussed in wind-tunnel tests in the preliminary design phase of the silent supersonic technology demonstrator (S3TD). The static aeroelastic deformation of the main wing is estimated for JAXA 2m x 2m transonic wind-tunnel and 1m x 1m supersonic wind-tunnel by a finite element method (FEM) structural analysis in which its structural model is tuned with the model deformation calibratio...

  9. Flowing of supersonic underexpanded micro-jets in the range of moderate Reynolds numbers

    Science.gov (United States)

    Mironov, S. G.; Aniskin, V. M.; Maslov, A. A.

    2017-10-01

    The paper presents new experimental results on the simulation of supersonic underexpanded micro-jets by macro-jet in the range of moderate Reynolds numbers of air outflow from the nozzle. A correlation is shown between the variations in the Pitot pressure in the model micro-jet with variations in the length of the supersonic core of real the micro-jets. The results of experiments on the effect of humidity on the pulsation of mass flow rate in a micro-jet are presented.

  10. Supersonic acoustic intensity with statistically optimized near-field acoustic holography

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn

    2011-01-01

    The concept of supersonic acoustic intensity was introduced some years ago for estimating the fraction of the flow of energy radiated by a source that propagates to the far field. It differs from the usual (active) intensity by excluding the near-field energy resulting from evanescent waves...... to the information provided by the near-field acoustic holography technique. This study proposes a version of the supersonic acoustic intensity applied to statistically optimized near-field acoustic holography (SONAH). The theory, numerical results and an experimental study are presented. The possibility of using...

  11. Fully unsteady subsonic and supersonic potential aerodynamics for complex aircraft configurations for flutter applications

    Science.gov (United States)

    Tseng, K.; Morino, L.

    1975-01-01

    A general theory for study, oscillatory or fully unsteady potential compressible aerodynamics around complex configurations is presented. Using the finite-element method to discretize the space problem, one obtains a set of differential-delay equations in time relating the potential to its normal derivative which is expressed in terms of the generalized coordinates of the structure. For oscillatory flow, the motion consists of sinusoidal oscillations around a steady, subsonic or supersonic flow. For fully unsteady flow, the motion is assumed to consist of constant subsonic or supersonic speed for time t or = 0 and of small perturbations around the steady state for time t 0.

  12. On the Scaling Law for Broadband Shock Noise Intensity in Supersonic Jets

    Science.gov (United States)

    Kanudula, Max

    2009-01-01

    A theoretical model for the scaling of broadband shock noise intensity in supersonic jets was formulated on the basis of linear shock-shear wave interaction. An hypothesis has been postulated that the peak angle of incidence (closer to the critical angle) for the shear wave primarily governs the generation of sound in the interaction process rather than the noise generation contribution from off-peak incident angles. The proposed theory satisfactorily explains the well-known scaling law for the broadband shock -associated noise in supersonic jets.

  13. Compilation and Review of Supersonic Business Jet Studies from 1963 through 1995

    Science.gov (United States)

    Maglieri, Domenic J.

    2011-01-01

    This document provides a compilation of all known supersonic business jet studies/activities conducted from 1963 through 1995 by university, industry and the NASA. First, an overview is provided which chronologically displays all known supersonic business jet studies/activities conducted by universities, industry, and the NASA along with the key features of the study vehicles relative to configuration, planform, operation parameters, and the source of study. This is followed by a brief description of each study along with some comments on the study. Mention will be made as to whether the studies addressed cost, market needs, and the environmental issues of airport-community noise, sonic boom, and ozone.

  14. Nozzle flow calculation for real gases

    International Nuclear Information System (INIS)

    Bier, K.; Ehrler, F.; Hartz, U.; Kissau, G.

    1977-01-01

    The flow of CHF 2 Cl vapor (refrigerant R 22) through a Laval nozzle of annular geometry has been investigated in the region near the saturation line with stagnation pressures up to 85 per cent of the critical pressure. Static pressure profiles measured along the nozzle axis were found in good agreement with profiles calculated for one-dimensional isentropic flow of the real gas the thermal properties of which were derived from an equation of state proposed previously by Rombusch. Minor deviations between measured and calculated static pressure curves occur in the supersonic part of the mozzle, especially when supersaturated states of the vapour are passed. These deviations can be attributed to uncertainties in the calculation of the enthalpy and to a small influence of the static pressure probe. An additional investigation was concerned with an approximate calculation of the nozzle flow of real gases. In this approximation the well known relations of ideal gas dynamics are applied, the ratio of specific heats for the ideal gas being replaced, however, by a suitably adapted isentropic exponent, which can be determined e.g. from measured values of the Laval pressure or of the mass flow. For pressure ratios p/po between 1 and approximately 0.1, corresponding to Mach numbers up to approximately 2.2, all the interesting properties of the investigated flow of CHF 2 Cl vapour are approximated within a few per cent. (orig.) [de

  15. Calculation of external-internal flow fields for mixed-compression inlets

    Science.gov (United States)

    Chyu, W. J.; Kawamura, T.; Bencze, D. P.

    1987-01-01

    Supersonic inlet flows with mixed external-internal compressions were computed using a combined implicit-explicit (Beam-Warming-Steger/MacCormack) method for solving the three-dimensional unsteady, compressible Navier-Stokes equations in conservation form. Numerical calculations were made of various flows related to such inlet operations as the shock-wave intersections, subsonic spillage around the cowl lip, and inlet started versus unstarted conditions. Some of the computed results were compared with wind tunnel data.

  16. CALCULATION OF ROCKET NOSE FAIRING SHELLS AERODYNAMIC CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    Vladimir T. Kalugin

    2018-01-01

    Full Text Available The aerodynamic characteristics of the detachable elements of transport systems are introduced, they allow to calculate the trajectories of these elements after their separation and determine the size of elements impact areas. Special consideration is given to head fairing shells, containing cylindrical, conical and spherical sections. Head fairing shells have high lift-to-drag ratio and the widest impact areas. Aerodynamics of bodies of such configurations has been insufficiently studied. The paper presents the numerical results of modeling the flow around a typical head fairing shell in free flight. Open source OpenFOAM package is used for numerical simulation. The aerodynamic characteristics at trans- and supersonic velocities are obtained, flow pattern transformation with the change of the angle of attack and Mach number is analyzed. The possibility of OpenFOAM package for aerodynamic calculations of thin shells is shown. The analysis of the obtained results demonstrate that there are many complex shock waves interacting with each other at flow supersonic speeds, at subsonic speeds vast regions of flow separations are observed. The authors identify intervals of angles of attack, where different types of flow structures are realized, both for trans- and supersonic flow speeds. The flow pattern change affects the aerodynamic characteristics, the aerodynamic coefficients significantly change with increase of the angle of attack. There are two trim angles of attack at all examined flow velocities. The results obtained can be used to develop a passive stabilization system for fairing shell that will balance the body at the angle of attack with minimum lift-to-drag ratio and will reduce random deviations.

  17. Computational results for the effects of external disturbances on transition location of bodies of revolution from subsonic to supersonic speeds and comparisons with experimental data

    Science.gov (United States)

    Goradia, S. H.; Bobbitt, P. J.; Harvey, W. D.

    1989-01-01

    Computational experiments have been performed for a few configurations in order to investigate the effects of external flow disturbances on the extent of laminar flow and wake drag. Theoretical results have been compared with experimental data for the AEDC cone, for Mach numbers from subsonic to supersonic, and for both free flight and wind tunnel environments. The comparisons have been found to be very satisfactory, thus establishing the utility of the present method for the design and development of laminar flow configurations and for the assessment of wind tunnel data. In addition, results of calculations concerning the effects of unit Reynolds numbers on transition are presented. In addition to the AEDC cone, computations have been performed for an ogive body of revolution at zero angle of attack and supersonic Mach numbers. Results are presented for transition Reynolds number and wake drag for external disturbances corresponding to free air and the test section of the AEDC-VKF tunnel. These results have been found to compare quite well with wind tunnel data for cases when surface suction is applied as well as when suction is absent.

  18. Double linearization theory applied to three-dimensional cascades oscillating under supersonic axial flow condition. Choonsoku jikuryu sokudo de sadosuru sanjigen shindo yokuretsu no niju senkei riron ni yoru hiteijo kukiryoku kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Toshimitsu, K; Nanba, M [Kgushu University, Fukuoka (Japan). Faculty of Engineering; Iwai, S [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1993-11-25

    In order to examine the aerodynamic characteristics of a supersonic axial flow turbofan realizing flight of Mach number of 2-5, the double linearization theory was applied to a three dimensional oscillation cascade accompanying a steady load in a supersonic axial flow condition and unsteady pneumatic force and aerodynamic unstability of oscillation were studied. Moreover, the values based on the strip theory and the three-dimensional theory were comparatively evaluated. Fundamental assumptions were such that the order of steady and unsteady perturbation satisfies the holding condition of the double linearization thory in a supersonic-and equi-entropy flow of non-viscous perfect gas. The numerical calculation assumed parabolic distributions of camber and thickness in the blade shape. As a result, the strip theory prediction agreed well with the value given by the three-dimensional theory in the steady blade-plane pressure difference and in the work of an unsteady pneumatic force, showing its validity. Among the steady load components of angle of attack, camber and thickness, the component of camber whose absolute value is large has the strongest effect on the total work. The distribution reduced in the angle of attack and camber from hub toward tip gives a large and stable flutter margin. 5 refs., 13 figs., 2 tabs.

  19. Computational Study of Shock/Plume Interactions Between Multiple Jets in Supersonic Crossflow

    Science.gov (United States)

    Tylczak, Erik B.

    The interaction of multiple jets in supersonic crossflow is simulated using hybrid Reynolds- Averaged Navier Stokes and Large Eddy Simulation turbulence models. The blockage of a jet generates a curved bow shock, and in multi-jet flows, each shock impinges on the other fuel plumes. The curved nature of each shock generates vorticity directly, and the impingement of each shock on the vortical structures within the adjacent fuel plumes strengthens vortical structures already present. These stirring motions are the major driver of fuel-air mixing, and so mixing enhancement is predicted to occur in multi-port configurations. The primary geometry considered is that of the combustion duct at the Calspan- University of Buffalo Research Center 48" Large Energy National Shock (LENS) tunnel. This geometry was developed to be representative of the geometry and flow physics of the Flight 2 test vehicle of the Hypersonic International Flight Research Experimenta- tion Program (HiFIRE-2). This geometry takes the form of a symmetric pair of external compression ramps that feed an isolator of approximately 4" x 1" cross-section. Nine interdigitated flush-wall injectors, four on one wall and five on the other, inject hydrogen at an angle of 30 degrees to the freestream. Two freestream flow conditions are consid- ered: approximately Mach 7.2 at a static temperature of 214K and a density of 0.039 kg/m3 for the five-injector case, and approximately Mach 8.9 at a static temperature of 167K and density of 0.014 kg/m 3 for the nine-injector case. Validation computations are performed on a single-port experiment with an imposed shock wave. Unsteady calculations are performed on five-port and nine-port configura- tions, and the five-port configuration is compared to calculations performed with only a single active port on the same geometry. Analysis of statistical data demonstrates enhanced mixing in the multi-port configurations in regions where shock impingement occurs.

  20. Shock Waves Oscillations in the Interaction of Supersonic Flows with the Head of the Aircraft

    Science.gov (United States)

    Bulat, Pavel V.; Volkov, Konstantin N.

    2016-01-01

    In this article we reviewed the shock wave oscillation that occurs when supersonic flows interact with conic, blunt or flat nose of aircraft, taking into account the aerospike attached to it. The main attention was paid to the problem of numerical modeling of such oscillation, flow regime classification, and cases where aerospike attachment can…

  1. Dissymmetry effects on the laser spectroscopy of supersonically expanded rare gas/chiral arene heteroclusters.

    Science.gov (United States)

    Filippi, Antonello; Giardini, Anna; Marcantoni, Enrico; Paladini, Alessandra; Piccirillo, Susanna; Renzi, Gabriele; Rondino, Flaminia; Roselli, Graziella; Satta, Mauro; Speranza, Maurizio

    2007-04-14

    The R2PI-TOF spectra of supersonically expanded rare gas/chiral arene heteroclusters have been rationalized in terms of the distortion of the pi-electron density reflecting the different dipole and quadrupole momenta induced in the rare gas atoms by interaction with the opposite pi-faces of the chiral arene itself.

  2. Micro Ramps in Supersonic Turbulent Boundary Layers : An experimental and numerical study

    NARCIS (Netherlands)

    Sun, Z.

    2014-01-01

    The micro vortex generator (MVG) is used extensively in low speed aerodynamic problems and is now extended into the supersonic flow regime to solve undesired flow features that are associated with shock wave boundary layer interactions (SWBLI) such as flow separation and associated unsteadiness of

  3. CFD application to supersonic/hypersonic inlet airframe integration. [computational fluid dynamics (CFD)

    Science.gov (United States)

    Benson, Thomas J.

    1988-01-01

    Supersonic external compression inlets are introduced, and the computational fluid dynamics (CFD) codes and tests needed to study flow associated with these inlets are outlined. Normal shock wave turbulent boundary layer interaction is discussed. Boundary layer control is considered. Glancing sidewall shock interaction is treated. The CFD validation of hypersonic inlet configurations is explained. Scramjet inlet modules are shown.

  4. Description of a laser vaporization source and a supersonic cluster beam apparatus

    International Nuclear Information System (INIS)

    Doverstaal, M.; Lindgren, B.; Sassenberg, U.; Yu, H.

    1993-11-01

    Laser vaporization of an appropriate target and recent developments in molecular beam technology have now made it possible to produce supersonic cluster beams of virtually any element in the periodic table. This paper describes the design and principles of a cluster source combined with a time of flight mass spectrometer built for reaction experiments and spectroscopic investigations at Stockholm University

  5. Effect of inlet and outlet flow conditions on natural gas parameters in supersonic separation process.

    Directory of Open Access Journals (Sweden)

    Yan Yang

    Full Text Available A supersonic separator has been introduced to remove water vapour from natural gas. The mechanisms of the upstream and downstream influences are not well understood for various flow conditions from the wellhead and the back pipelines. We used a computational model to investigate the effect of the inlet and outlet flow conditions on the supersonic separation process. We found that the shock wave was sensitive to the inlet or back pressure compared to the inlet temperature. The shock position shifted forward with a higher inlet or back pressure. It indicated that an increasing inlet pressure declined the pressure recovery capacity. Furthermore, the shock wave moved out of the diffuser when the ratio of the back pressure to the inlet one was greater than 0.75, in which the state of the low pressure and temperature was destroyed, resulting in the re-evaporation of the condensed liquids. Natural gas would be the subsonic flows in the whole supersonic separator, if the mass flow rate was less than the design value, and it could not reach the low pressure and temperature for the condensation and separation of the water vapor. These results suggested a guidance mechanism for natural gas supersonic separation in various flow conditions.

  6. CFD modeling of particle behavior in supersonic flows with strong swirls for gas separation

    DEFF Research Database (Denmark)

    Yang, Yan; Wen, Chuang

    2017-01-01

    flow from the dry gas outlet. The separation efficiency reached over 80%, when the droplet diameter was more than 1.5 μm. The optimum length of the cyclonic separation section was approximate 16–20 times of the nozzle throat diameter to obtain higher collection efficiency for the supersonic separator...

  7. Effect of a Finite Trailing Edge Thickness on the Drag of Rectangular and Delta Wings at Supersonic Speeds

    National Research Council Canada - National Science Library

    Klunker, E

    1952-01-01

    The effect of a finite trailing-edge thickness on the pressure drag of rectangular and delta wings with truncated diamond-shaped airfoil sections with a given thickness ratio is studied for supersonic...

  8. Investigation of the Impact of an External Magnetic Field on a Supersonic Plasma Flow Through and MGD Channel

    National Research Council Canada - National Science Library

    Bobashev, S. V; Mende, N. P; Sakharov, V. A; Van Wie, D. M

    2003-01-01

    .... Generally, the separation leads to harmful consequences such as an increase of the body drag, a decrease of the wing lift, unsteady loads, and at high supersonic velocities causes emergence of narrow...

  9. Predictions of wet natural gases condensation rates via multi-component and multi-phase simulation of supersonic separators

    International Nuclear Information System (INIS)

    Shooshtari, Seyed Heydar Rajaee; Shahsavand, Akbar

    2014-01-01

    Proper correction of water and heavy hydrocarbon dew points of sweet natural gases is essential from various technical and economical standpoints. Supersonic separators (3S) are proved to be capable of achieving these tasks with maximum reliability and minimal expenses. The majority of the previous articles have focused on the flow behavior of pure fluids across a 3S unit. Multicomponent fluid flow inside 3S accompanied with condensation phenomenon will drastically increase the complexity of the simulation process. We tackle this issue by considering a proper combination of fundamental governing equations and phase equilibrium calculations to predict various operating conditions and composition profiles across two multi-component and multi-phase 3S units. Various Iranian sweet gases are used as real case studies to demonstrate the importance of 3S unit practical applications. Simulation results clearly illustrate the effectiveness of 3S units for faithful dehydration of various natural gases, while successfully controlling its dew point, suitable for any practical applications. Conventional HYSYS simulation software is used to validate the simulation results

  10. Spatially and Temporally Resolved Measurements of Velocity in a H2-air Combustion-Heated Supersonic Jet

    Science.gov (United States)

    Bivolaru, Daniel; Cutler, Andrew D.; Danehy, Paul M.; Gaffney, Richard L.; Baurle, Robert a.

    2009-01-01

    This paper presents simultaneous measurements at multiple points of two orthogonal components of flow velocity using a single-shot interferometric Rayleigh scattering (IRS) technique. The measurements are performed on a large-scale Mach 1.6 (Mach 5.5 enthalpy) H2-air combustion jet during the 2007 test campaign in the Direct Connect Supersonic Combustion Test facility at NASA Langley Research Center. The measurements are performed simultaneously with CARS (Coherent Anti-stokes Raman Spectroscopy) using a combined CARS-IRS instrument with a common path 9-nanosecond pulsed, injection-seeded, 532-nm Nd:YAG laser probe pulse. The paper summarizes the measurements of velocities along the core of the vitiated air flow as well as two radial profiles. The average velocity measurement near the centerline at the closest point from the nozzle exit compares favorably with the CFD calculations using the VULCAN code. Further downstream, the measured axial velocity shows overall higher values than predicted with a trend of convergence at further distances. Larger discrepancies are shown in the radial profiles.

  11. Effects of Forward- and Backward-Facing Steps on the Crossflow Receptivity and Stability in Supersonic Boundary Layers

    Science.gov (United States)

    Balakumar, P.; King, Rudolph A.; Eppink, Jenna L.

    2014-01-01

    The effects of forward- and backward-facing steps on the receptivity and stability of three-dimensional supersonic boundary layers over a swept wing with a blunt leading edge are numerically investigated for a freestream Mach number of 3 and a sweep angle of 30 degrees. The flow fields are obtained by solving the full Navier-Stokes equations. The evolution of instability waves generated by surface roughness is simulated with and without the forward- and backward-facing steps. The separation bubble lengths are about 5-10 step heights for the forward-facing step and are about 10 for the backward-facing step. The linear stability calculations show very strong instability in the separated region with a large frequency domain. The simulation results show that the presence of backward-facing steps decreases the amplitude of the stationary crossflow vortices with longer spanwise wavelengths by about fifty percent and the presence of forward-facing steps does not modify the amplitudes noticeably across the steps. The waves with the shorter wavelengths grow substantially downstream of the step in agreement with the linear stability prediction.

  12. Validation of Shear Wave Elastography Cutoff Values on the Supersonic Aixplorer for Practical Clinical Use in Liver Fibrosis Staging.

    Science.gov (United States)

    Dhyani, Manish; Grajo, Joseph R; Bhan, Atul K; Corey, Kathleen; Chung, Raymond; Samir, Anthony E

    2017-06-01

    The purpose of this study was to determine the validity of previously established ultrasound shear wave elastography (SWE) cut-off values (≥F2 fibrosis) on an independent cohort of patients with chronic liver disease. In this cross-sectional study, approved by the institutional review board and compliant with the Health Insurance Portability and Accountability Act, 338 patients undergoing liver biopsy underwent SWE using an Aixplorer ultrasound machine (SuperSonic Imagine, Aix-en-Provence, France). Median SWE values were calculated from sets of 10 elastograms. A single blinded pathologist evaluated METAVIR fibrosis staging as the gold standard. The study analyzed 277 patients with a mean age of 48 y. On pathologic examination, 212 patients (76.5%) had F0-F1 fibrosis, whereas 65 (23.5%) had ≥F2 fibrosis. Spearman's correlation of fibrosis with SWE was 0.456 (p Aixplorer SWE system. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  13. First steps towards a generic sample preparation scheme for inorganic engineered nanoparticles in a complex matrix for detection, characterization, and quantification by asymmetric flow-field flow fractionation coupled to multi-angle light scattering and ICP-MS

    DEFF Research Database (Denmark)

    Wagner, Stephan; Legros, Samuel; Löschner, Katrin

    2015-01-01

    content by asymmetric flow-field flow fractionation coupled to a multi-angle light scattering detector and an inductively coupled plasma mass spectrometer. Following the proposed generic procedure SiO2-ENPs were separated from a tomato soup. Two potential sample preparation methods were tested these being...... quality criteria for method development is urgently needed for standardized and systematic development of procedures for separation of ENPs from a complex matrix. The chosen analytical technique was shown to be suitable for detecting SiO2-ENPs in a complex food matrix like tomato soup and may therefore...

  14. Pressure Measurement and Flowfield Characterization of a Two-Dimensional Ideally Expanded, Constant Area, Air/air Ejector.

    Science.gov (United States)

    Benjamin, Michael Anthony

    A detailed experimental investigation of a two -dimensional, Mach 1.8 air-primary, Mach 0.3 air-secondary ejector at high Reynolds number has been performed, from which a nonintrusive method for whole-field visualization using turbulent wall-pressure has been developed. The experiments were conducted using mean and time-accurate wall pressure measurements, impact-pressure measurements using a traversing probe, and Schlieren and shadowgraph visualization techniques. The time-accurate pressure measurements were recorded using a sealed Kulite miniature pressure transducer with a 0.7 mm diameter sensing diaphragm. For all except the optical methods, measurements were taken from the initial flow interface to about 13 hydraulic tube-diameters downstream in the constant-area mixing section. From the mean measurements, values of stagnation pressure, density, velocity, static pressure, Mach number, and dynamic pressure were developed and are presented. Using the time-accurate pressure measurements, a color contour plot of the rms pressure was developed that definitively shows the regions of the flow in agreement with the other measurements. Additionally, probability density functions, skewness, and kurtosis were calculated. Peak values of skewness (S) and kurtosis (K) on the centerline at about 2.5 hydraulic diameters are S = 1.85 and K = 11.5. The inlet rms pressure values, normalized by freestream dynamic pressure for the primary (~0.001), were found to be in fair agreement with previous experimental values; however, those in the secondary were much higher (~0.2), apparently due to the acoustic radiation from the primary. Fourier analysis of the time-accurate pressure measurements show that the autospectra contain k ^{-1}, k^{-7/3}, and k^{-11/3} pressure spectrum functions as predicted by prevailing theory for the overlap layer, turbulence-turbulence interaction, and turbulence-mean-shear interaction, respectively. It is believed that this is the first experiment in

  15. An Experimental Study of Turbulent Skin Friction Reduction in Supersonic Flow Using a Microblowing Technique

    Science.gov (United States)

    Hwang, Danny P.

    1999-01-01

    A new turbulent skin friction reduction technology, called the microblowing technique has been tested in supersonic flow (Mach number of 1.9) on specially designed porous plates with microholes. The skin friction was measured directly by a force balance and the boundary layer development was measured by a total pressure rake at the tailing edge of a test plate. The free stream Reynolds number was 1.0(10 exp 6) per meter. The turbulent skin friction coefficient ratios (C(sub f)/C(sub f0)) of seven porous plates are given in this report. Test results showed that the microblowing technique could reduce the turbulent skin friction in supersonic flow (up to 90 percent below a solid flat plate value, which was even greater than in subsonic flow).

  16. A review and development of correlations for base pressure and base heating in supersonic flow

    Energy Technology Data Exchange (ETDEWEB)

    Lamb, J.P. [Texas Univ., Austin, TX (United States). Dept. of Mechanical Engineering; Oberkampf, W.L. [Sandia National Labs., Albuquerque, NM (United States)

    1993-11-01

    A comprehensive review of experimental base pressure and base heating data related to supersonic and hypersonic flight vehicles has been completed. Particular attention was paid to free-flight data as well as wind tunnel data for models without rear sting support. Using theoretically based correlation parameters, a series of internally consistent, empirical prediction equations has been developed for planar and axisymmetric geometries (wedges, cones, and cylinders). These equations encompass the speed range from low supersonic to hypersonic flow and laminar and turbulent forebody boundary layers. A wide range of cone and wedge angles and cone bluntness ratios was included in the data base used to develop the correlations. The present investigation also included preliminary studies of the effect of angle of attack and specific-heat ratio of the gas.

  17. Characteristics and measurement of supersonic projectile shock waves by a 32-microphone ring array

    Science.gov (United States)

    Chang, Ho; Wu, Yan-Chyuan; Tsung, Tsing-Tshih

    2011-08-01

    This paper discusses about the characteristics of supersonic projectile shock wave in muzzle region during firing of high explosive anti-tank (HEAT) and high explosive (HE) projectiles. HEAT projectiles are fired horizontally at a muzzle velocity of Mach 3.5 from a medium caliber tank gun equipped with a newly designed multi-perforated muzzle brake, whereas HE projectiles are fired at elevation angles at a muzzle velocity of Mach 2 from a large caliber howitzer equipped with a newly designed double-baffle muzzle brake. In the near field, pressure signatures of the N-wave generated from projectiles are measured by 32-microphone ring array wrapped by cotton sheath. Records measured by the microphone array are used to demonstrate several key characteristics of the shock wave of supersonic projectile. All measurements made in this study can be a significant reference for developing guns, tanks, or the chassis of fighting vehicles.

  18. Propulsion System Dynamic Modeling of the NASA Supersonic Concept Vehicle for AeroPropulsoServoElasticity

    Science.gov (United States)

    Kopasakis, George; Connolly, Joseph W.; Seiel, Jonathan

    2016-01-01

    A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report

  19. An Automated DAKOTA and VULCAN-CFD Framework with Application to Supersonic Facility Nozzle Flowpath Optimization

    Science.gov (United States)

    Axdahl, Erik L.

    2015-01-01

    Removing human interaction from design processes by using automation may lead to gains in both productivity and design precision. This memorandum describes efforts to incorporate high fidelity numerical analysis tools into an automated framework and applying that framework to applications of practical interest. The purpose of this effort was to integrate VULCAN-CFD into an automated, DAKOTA-enabled framework with a proof-of-concept application being the optimization of supersonic test facility nozzles. It was shown that the optimization framework could be deployed on a high performance computing cluster with the flow of information handled effectively to guide the optimization process. Furthermore, the application of the framework to supersonic test facility nozzle flowpath design and optimization was demonstrated using multiple optimization algorithms.

  20. SGS Modeling of the Internal Energy Equation in LES of Supersonic Channel Flow

    Science.gov (United States)

    Raghunath, Sriram; Brereton, Giles

    2011-11-01

    DNS of fully-developed turbulent supersonic channel flows (Reτ = 190) at up to Mach 3 indicate that the turbulent heat fluxes depend only weakly on Mach number, while the viscous dissipation and pressure dilatation do so strongly. Moreover, pressure dilatation makes a significant contribution to the internal energy budget at Mach 3 and higher. The balance between these terms is critical to determining the temperature (and so molecular viscosity) from the internal energy equation and so, in LES of these flows, it is essential to use accurate SGS models for the viscous dissipation and the pressure dilatation. In this talk, we present LES results for supersonic channel flow, using SGS models for these terms that are based on the resolved-scale dilatation, an inverse timescale, and SGS momentum fluxes, which intrinsically represent this Mach number effect.

  1. Preliminary study of optimum ductburning turbofan engine cycle design parameters for supersonic cruising

    Science.gov (United States)

    Fishbach, L. H.

    1978-01-01

    The effect of turbofan engine overall pressure ratio, fan pressure ratio, and ductburner temperature rise on the engine weight and cruise fuel consumption for a mach 2.4 supersonic transport was investigated. Design point engines, optimized purely for the supersonic cruising portion of the flight where the bulk of the fuel is consumed, are considered. Based on constant thrust requirements at cruise, fuel consumption considerations would favor medium by pass ratio engines (1.5 to 1.8) of overall pressure ratio of about 16. Engine weight considerations favor low bypass ratio (0.6 or less) and low wverall pressure ratio (8). Combination of both effects results in bypass ratios of 0.6 to 0.8 and overall pressure ratio of 12 being the overall optimum.

  2. Characteristics of an under-expanded supersonic flow in arcjet plasmas

    Science.gov (United States)

    Namba, Shinichi; Shikama, Taiichi; Sasano, Wataru; Tamura, Naoki; Endo, Takuma

    2018-06-01

    A compact apparatus to produce arcjet plasma was fabricated to investigate supersonic flow dynamics. Periodic bright–dark emission structures were formed in the arcjets, depending on the plasma source and ambient gas pressures in the vacuum chamber. A directional Langmuir probe (DLP) and emission spectroscopy were employed to characterize plasma parameters such as the Mach number of plasma flows and clarify the mechanism for the generation of the emission pattern. In particular, in order to investigate the influence of the Mach number on probe size, we used two DLPs of different probe size. The results indicated that the arcjets could be classified into shock-free expansion and under-expansion, and the behavior of plasma flow could be described by compressible fluid dynamics. Comparison of the Langmuir probe results with emission and laser absorption spectroscopy showed that the small diameter probe was reliable to determine the Mach number, even for the supersonic jet.

  3. A multiple-scales model of the shock-cell structure of imperfectly expanded supersonic jets

    Science.gov (United States)

    Tam, C. K. W.; Jackson, J. A.; Seiner, J. M.

    1985-01-01

    The present investigation is concerned with the development of an analytical model of the quasi-periodic shock-cell structure of an imperfectly expanded supersonic jet. The investigation represents a part of a program to develop a mathematical theory of broadband shock-associated noise of supersonic jets. Tam and Tanna (1982) have suggested that this type of noise is generated by the weak interaction between the quasi-periodic shock cells and the downstream-propagating large turbulence structures in the mixing layer of the jet. In the model developed in this paper, the effect of turbulence in the mixing layer of the jet is simulated by the addition of turbulent eddy-viscosity terms to the momentum equation. Attention is given to the mean-flow profile and the numerical solution, and a comparison of the numerical results with experimental data.

  4. Reduction of the suction pressure of a liquid ring vacuum pump with a supersonic gas ejector

    Directory of Open Access Journals (Sweden)

    Olšiak Róbert

    2018-01-01

    Full Text Available A supersonic gas ejector in conjunction with a liquid ring vacuum pump is used for creating and maintaining vacuum in a chamber for technological purposes. In this paper the authors submit an overview about the problematics of suction pressure reduction with a supersonic gas ejector used as a pre-stage of a liquid ring vacuum pump. This system has also the function of a cavitation protection due to the higher pressure present at the suction throat of the vacuum pump. A part of this paper is devoted to the governing equations used at the definition of the flow through an ejector. The experimental studies are then carried out in or own laboratory for verification purposes.

  5. Aerodynamic forces estimation on jet vanes exposed to supersonic exhaust of a CD Nozzle

    International Nuclear Information System (INIS)

    Bukhari, S.B.H.; Jehan, I.; Zahir, S.; Khan, M.A.

    2003-01-01

    A comprehensive study has been made for the estimation of aerodynamic forces on the jet Vane placed in the supersonic exhaust of a Convergent Divergent, CD-Nozzle. Such a system is used to provide the control forces that consist of four orthogonal vanes mounted in the supersonic exhaust of the CD-Nozzles. The flow field parameters for a CD Nozzle were analyzed and validated earlier. In this paper the published experimental and CFD results from RAMPANT Code from Fluent Inc. were used to estimate the axial and normal forces by using PAK-3D, a Computational Fluid Dynamics (CFD) software based on Navier-Stokes Equations solver. Results got verified quantitatively with a maximum error of 8% between PAK-3D and experiment, while 4% between PAK-3D and a CFD code, RAMPANT for the axial force. (author)

  6. Large-Amplitude Long-Wave Instability of a Supersonic Shear Layer

    Science.gov (United States)

    Messiter, A. F.

    1995-01-01

    For sufficiently high Mach numbers, small disturbances on a supersonic vortex sheet are known to grow in amplitude because of slow nonlinear wave steepening. Under the same external conditions, linear theory predicts slow growth of long-wave disturbances to a thin supersonic shear layer. An asymptotic formulation is given here which adds nonzero shear-layer thickness to the weakly nonlinear formulation for a vortex sheet. Spatial evolution is considered, for a spatially periodic disturbance having amplitude of the same order, in Reynolds number, as the shear-layer thickness. A quasi-equilibrium inviscid nonlinear critical layer is found, with effects of diffusion and slow growth appearing through nonsecularity condition. Other limiting cases are also considered, in an attempt to determine a relationship between the vortex-sheet limit and the long-wave limit for a thin shear layer; there appear to be three special limits, corresponding to disturbances of different amplitudes at different locations along the shear layer.

  7. Advanced Supersonic Nozzle Concepts: Experimental Flow Visualization Results Paired With LES

    Science.gov (United States)

    Berry, Matthew; Magstadt, Andrew; Stack, Cory; Gaitonde, Datta; Glauser, Mark; Syracuse University Team; The Ohio State University Team

    2015-11-01

    Advanced supersonic nozzle concepts are currently under investigation, utilizing multiple bypass streams and airframe integration to bolster performance and efficiency. This work focuses on the parametric study of a supersonic, multi-stream jet with aft deck. The single plane of symmetry, rectangular nozzle, displays very complex and unique flow characteristics. Flow visualization techniques in the form of PIV and schlieren capture flow features at various deck lengths and Mach numbers. LES is compared to the experimental results to both validate the computational model and identify limitations of the simulation. By comparing experimental results to LES, this study will help create a foundation of knowledge for advanced nozzle designs in future aircraft. SBIR Phase II with Spectral Energies, LLC under direction of Barry Kiel.

  8. A pulser-sustainer carbon monoxide electric-discharge supersonic laser

    Science.gov (United States)

    Monson, D. J.; Srinivasan, G.

    1977-01-01

    Operation of a CW CO electric-discharge supersonic laser with a pulser-sustainer discharge is described. High-power operation as well as independent control over electron energy and density are demonstrated. Maximum input power achieved to date is 100 kW. The maximum output power is 6 kW or 10% of the sustainer positive-column power. Much improved performance appears possible.

  9. Parameters of the plasma of a dc pulsating discharge in a supersonic air flow

    Energy Technology Data Exchange (ETDEWEB)

    Shibkov, V. M., E-mail: shibkov@phys.msu.ru; Shibkova, L. V.; Logunov, A. A. [Moscow State University, Faculty of Physics (Russian Federation)

    2017-03-15

    A dc discharge in a cold (T = 200 K) supersonic air flow at a static pressure of 200–400 Torr was studied experimentally. The excited unsteady pulsating discharge has the form of a thin plasma channel with a diameter of ≤1 mm, stretched downstream the flow. Depending on the discharge current, the pulsation frequency varies from 800 to 1600 Hz and the electron temperature varies from 8000 to 15000 K.

  10. Towards numerical simulations of supersonic liquid jets using ghost fluid method

    International Nuclear Information System (INIS)

    Majidi, Sahand; Afshari, Asghar

    2015-01-01

    Highlights: • A ghost fluid method based solver is developed for numerical simulation of compressible multiphase flows. • The performance of the numerical tool is validated via several benchmark problems. • Emergence of supersonic liquid jets in quiescent gaseous environment is simulated using ghost fluid method for the first time. • Bow-shock formation ahead of the liquid jet is clearly observed in the obtained numerical results. • Radiation of mach waves from the phase-interface witnessed experimentally is evidently captured in our numerical simulations. - Abstract: A computational tool based on the ghost fluid method (GFM) is developed to study supersonic liquid jets involving strong shocks and contact discontinuities with high density ratios. The solver utilizes constrained reinitialization method and is capable of switching between the exact and approximate Riemann solvers to increase the robustness. The numerical methodology is validated through several benchmark test problems; these include one-dimensional multiphase shock tube problem, shock–bubble interaction, air cavity collapse in water, and underwater-explosion. A comparison between our results and numerical and experimental observations indicate that the developed solver performs well investigating these problems. The code is then used to simulate the emergence of a supersonic liquid jet into a quiescent gaseous medium, which is the very first time to be studied by a ghost fluid method. The results of simulations are in good agreement with the experimental investigations. Also some of the famous flow characteristics, like the propagation of pressure-waves from the liquid jet interface and dependence of the Mach cone structure on the inlet Mach number, are reproduced numerically. The numerical simulations conducted here suggest that the ghost fluid method is an affordable and reliable scheme to study complicated interfacial evolutions in complex multiphase systems such as supersonic liquid

  11. Strong coupling strategy for fluid-structure interaction problems in supersonic regime via fixed point iteration

    Science.gov (United States)

    Storti, Mario A.; Nigro, Norberto M.; Paz, Rodrigo R.; Dalcín, Lisandro D.

    2009-03-01

    In this paper some results on the convergence of the Gauss-Seidel iteration when solving fluid/structure interaction problems with strong coupling via fixed point iteration are presented. The flow-induced vibration of a flat plate aligned with the flow direction at supersonic Mach number is studied. The precision of different predictor schemes and the influence of the partitioned strong coupling on stability is discussed.

  12. Supersonic Cruise Research 1979, part 2. [airframe structures and materials, systems integration, economic analysis

    Science.gov (United States)

    1980-01-01

    Advances in airframe structure and materials technology for supersonic cruise aircraft are reported with emphasis on titanium and composite structures. The operation of the Concorde is examined as a baseline for projections into the future. A market survey of U.S. passenger attitudes and preferences, the impact of advanced air transport technology and the integration of systems for the advanced SST and for a smaller research/business jet vehicle are also discussed.

  13. Development of supersonic plasma flows by use of a magnetic nozzle and an ICRF heating

    Energy Technology Data Exchange (ETDEWEB)

    Inutake, M.; Ando, A.; Hattori, K.; Tobari, H.; Hosokawa, Y.; Sato, R.; Hatanaka, M.; Harata, K. [Tohoku Univ., Dept. of Electrical Engineering, Sendai (Japan)

    2004-07-01

    A high-beta, supersonic plasma flow plays a crucial role in MHD phenomena in space and fusion plasmas. There are a few experimental researches on production and control of a fast flowing plasma in spite of a growing significance in the magnetized-plasma flow dynamics. A magneto-plasma-dynamic arc-jet (MPDA) is one of promising devices to produce a supersonic plasma flow and has been utilized as an electric propulsion device with a higher specific impulse and a relatively larger thrust. We have improved the performance of an MPDA to produce a quasi-steady plasma flow with a transonic and supersonic Mach number in a highly-ionized state. There are two methods in order to control an ion-acoustic Mach number of the plasma flow exhausted from an MPDA: one is to use a magnetic Laval nozzle to convert a thermal energy to a flow energy and the other is a combined system of an ion heating and a divergent magnetic nozzle. The former is an analogous method to a compressible air flow and the latter is the method proposed in an advanced thruster for a manned interplanetary space mission. We have clarified the plasma flow characteristics in various shapes of a magnetic field configuration. It was demonstrated that the Mach number of the plasma flow could increase up to almost 3 in a divergent magnetic nozzle field. This paper reports recent results on the flow field improvements: one is on a magnetic-Laval-nozzle effects observed at the muzzle region of the MPDA, and the other is on ICRF (ion-cyclotron-range of frequency) heating of a supersonic plasma by use of a helical antenna. (authors)

  14. Measurements of gas velocity in supersonic flow using a laser beam

    International Nuclear Information System (INIS)

    Airoldi, V.J.T.; Santos, R. dos

    1982-01-01

    A study of measurements of supersonic velocities in a wind tunnel using a laser beam was performed. Techniques using lasers are most suitable because they do not disturb the gas flow. This work presents the technique entitled as fringe technique. It works using interference patterns due to two perpendicular laser beams crossing the sample (i.e. the gas flow). Experimental results are compared with other usual techniques. (R.S.)

  15. Study of supersonic flow in a constant rate of momentum change (CRMC) ejector with frictional effects

    International Nuclear Information System (INIS)

    Kumar, Virendra; Singhal, Gaurav; Subbarao, P.M.V.

    2013-01-01

    The constant rate of momentum change (CRMC) is a new approach towards design of supersonic ejectors. CRMC methodology was first proposed by Eames [1] in a study which was primarily based on isentropic flow inside the diffusing region of a supersonic ejector. The prime benefit that accrues from employing a CRMC ejector is that it can effectively eliminate the irreversibility associated with occurrence of thermodynamic shock process. The present study examines the supersonic flow in a CRMC ejector from the perspective of an adiabatic flow with frictional effects inside the variable cross-section of supersonic ejector, which is apparently more realistic. An analytical model has been discussed for the prediction of flow parameter variation in a space marching formulation taking into account change in localized frictional coefficient due to corresponding changes at each step. The analytical results have been validated by conducting a computational study based on 2-D axi-symmetric viscous compressible flow formulation with turbulence in FLUENT. The results are in good agreement at on-design conditions. The predictions especially for the recovered pressure made through the analytical formulation incorporating friction are found to be in significantly better agreement than the isentropic approach. The experimental validation for the approach has also been presented with the results being in close agreement with analytically predicted values. -- Highlights: • CRMC ejector eliminates the irreversibility due to occurrence of thermodynamic shock. • Frictional effect based apparently present more realistic solution for ejector. • Static pressure variation between proposed model and numerical study is nearly 2.29%. • Static pressure variation between analytical and experimental values is nearly 4%. • Experimentally observed entrainment ratio shows 3% variation w.r.t. design point value

  16. Determination of aerodynamic sensitivity coefficients in the transonic and supersonic regimes

    Science.gov (United States)

    Elbanna, Hesham M.; Carlson, Leland A.

    1989-01-01

    The quasi-analytical approach is developed to compute airfoil aerodynamic sensitivity coefficients in the transonic and supersonic flight regimes. Initial investigation verifies the feasibility of this approach as applied to the transonic small perturbation residual expression. Results are compared to those obtained by the direct (finite difference) approach and both methods are evaluated to determine their computational accuracies and efficiencies. The quasi-analytical approach is shown to be superior and worth further investigation.

  17. Flight assessment of a large supersonic drone aircraft for research use

    Science.gov (United States)

    Eckstrom, C. V.; Peele, E. L.

    1974-01-01

    An assessment is made of the capabilities of the BQM-34E supersonic drone aircraft as a test bed research vehicle. This assessment is made based on a flight conducted for the purpose of obtaining flight test measurements of wing loads at various maneuver flight conditions. Flight plan preparation, flight simulation, and conduct of the flight test are discussed along with a presentation of the test data obtained and an evaluation of how closely the flight test followed the test plan.

  18. Partial admission effect on the performance and vibration of a supersonic impulse turbine

    Science.gov (United States)

    Lee, Hang Gi; Shin, Ju Hyun; Choi, Chang-Ho; Jeong, Eunhwan; Kwon, Sejin

    2018-04-01

    This study experimentally investigates the effects of partial admission on the performance and vibration outcomes of a supersonic impulse turbine with circular nozzles. The turbine of a turbopump for a gas-generator-type liquid rocket engine in the Korea Space Launch Vehicle-II is of the supersonic impulse type with the partial admission configuration for obtaining a high specific power. Partial admission turbines with a low-flow-rate working gas exhibit benefits over turbines with full admission, such as loss reduction, ease of controllability of the turbine power output, and simple turbine configurations with separate starting sections. However, the radial force of the turbine rotor due to the partial admission causes an increase in turbine vibration. Few experimental studies have previously been conducted regarding the partial admission effects on supersonic impulse turbines with circular nozzles. In the present study, performance tests of supersonic impulse turbines with circular nozzles were conducted for various partial admission ratios using a turbine test facility with high-pressure air in order to investigate the resulting aerodynamic performance and vibration. Four types of turbines with partial admission ratios of 0.17, 0.42, 0.75 and 0.83 were tested. Results show that the efficiencies at the design point increase linearly as the partial admission ratios increase. Moreover, as the velocity ratios increase, the difference in efficiency from the reference turbine with a partial admission ratio of 0.83 becomes increasingly significant, and the magnitudes of these differences are proportional to the square of the velocity ratios. Likewise, the decrease in the partial admission ratio results in an increase in the turbine vibration level owing to the increase in the radial force.

  19. Aerodynamic Optimization of a Supersonic Bending Body Projectile by a Vector-Evaluated Genetic Algorithm

    Science.gov (United States)

    2016-12-01

    of offspring populations, the Student’s t-distribution is used as the convergence method. Equations 10–12 are the mean , variance , and standard...ARL-CR-0810 ● DEC 2016 US Army Research Laboratory Aerodynamic Optimization of a Supersonic Bending Body Projectile by a Vector...not return it to the originator. ARL-CR-0810 ● DEC 2016 US Army Research Laboratory Aerodynamic Optimization of a

  20. Interaction of intense electromagnetic fields with SF6 molecules and clusters in supersonic expansion

    International Nuclear Information System (INIS)

    Airoldi, V.J.T.

    1987-01-01

    A method of measuring SF 6 cluster formation and inhibition in pulsed supersonic expansion in the presence of intense electromagnetic radiation is presented. The characterization of the expansion of SF 6 molecules was done and, the extension of the collision region was determined. An improved unidimensional theory of supersonic expansion showed good agreement with the experimental results. The spectra of multiphoton absorption of SF 6 molecules in supersonic jet and the average energy absorved by each molecule were determined. The absorption spectra of molecule in the collision region present absorption maxima different from those obtained in the collisionless region. The results, if compared with the literature data, show good agreement, with a small difference in the spetra corresponding to the collisionless region. This difference was observed, for the first time in the multiphoton absorption and is attribuited to cluster formation in the jet. A new technique for measuring cluster formation in the supersonic jet, based on determination of the spatial distribution of the energy of molecules in the jet after passing through a skimmer located in the collision region is shown. The inhibition of cluster formation, due to the incidence of intense electromagnetic radiation from a CO 2 -TEA pulsed laser in the initial collision region of the jet, causes a second expansion in the skimmer. The results obtained show that this method can lead to a new isotope separation process. All the parts of the experimental set up, for example, high vacuum system, pulsed valve and pyroelectric detector, were developed and constructed specially for the experiment. (Author) [pt

  1. NASA's Pursuit of Low-Noise Propulsion for Low-Boom Commercial Supersonic Vehicles

    Science.gov (United States)

    Bridges, James; Brown, Clifford A.; Seidel, Jonathan A.

    2018-01-01

    Since 2006, when the Fundamental Aeronautics Program was instituted within NASA's Aeronautics Mission Directorate, there has been a Project looking at the technical barriers to commercial supersonic flight. Among the barriers is the noise produced by aircraft during landing and takeoff. Over the years that followed, research was carried out at NASA aeronautics research centers, often in collaboration with academia and industry, addressing the problem. In 2013, a high-level milestone was established, described as a Technical Challenge, with the objective of demonstrating the feasibility of a low-boom supersonic airliner that could meet current airport noise regulations. The Technical Challenge was formally called "Low Noise Propulsion for Low Boom Aircraft", and was completed in late 2016. This paper reports the technical findings from this Technical Challenge, reaching back almost 10 years to review the technologies and tools that were developed along the way. It also discusses the final aircraft configuration and propulsion systems required for a supersonic civilian aircraft to meet noise regulations using the technologies available today. Finally, the paper documents the model-scale tests that validated the acoustic performance of the study aircraft.

  2. Supersonic cluster beams: a powerful method for the deposition of nanostructured thin films with tailored properties

    International Nuclear Information System (INIS)

    Milani, P.

    2002-01-01

    By using a pulsed micro-plasma cluster source and by exploiting aero-dynamical effects typical of supersonic beams it is possible to obtain very high deposition rates with a control on neutral cluster mass distribution, allowing the deposition of thin films with controlled nanostructure. Due to high deposition rates, high lateral resolution, low temperature processing supersonic cluster beams can also be used for the micro and nano-patterning of cluster-assembled films when little or no post-growth manipulation or assembly is required. For example the nano and meso-structure of films obtained by carbon cluster beam deposition can be controlled by selecting in the beam the elemental building blocks, moreover functional properties such as field emission can be controlled and tailored. The use of supersonic cluster beams opens also new perspectives for the production of nano-structured films with novel physico-chemical and topological properties such as nano-structured carbon matrices containing carbide and transition metal particles. (Author)

  3. Effects of the shear layer growth rate on the supersonic jet noise

    Science.gov (United States)

    Ozawa, Yuta; Nonomura, Taku; Oyama, Akira; Mamori, Hiroya; Fukushima, Naoya; Yamamoto, Makoto

    2017-11-01

    Strong acoustic waves emitted from rocket plume might damage to rocket payloads because their payloads consist of fragile structure. Therefore, understanding and prediction of acoustic wave generation are of importance not only in science, but also in engineering. The present study makes experiments of a supersonic jet flow at the Mach number of 2.0 and investigates a relationship between growth rate of a shear layer and noise generation of the supersonic jet. We conducted particle image velocimetry (PIV) and acoustic measurements for three different shaped nozzles. These nozzles were employed to control the condition of a shear layer of the supersonic jet flow. We applied single-pixel ensemble correlation method (Westerweel et al., 2004) for the PIV images to obtain high-resolution averaged velocity profiles. This correlation method enabled us to obtain detailed data of the shear layer. For all cases, acoustic measurements clearly shows the noise source position at the end of a potential core of the jet. In the case where laminar to turbulent transition occurred in the shear layer, the sound pressure level increased by 4 dB at the maximum. This research is partially supported by Presto, JST (JPMJPR1678) and KAKENHI (25709009 and 17H03473).

  4. Interferometric measurement and numerical comparisons of supersonic heat transfer flows in microchannel

    International Nuclear Information System (INIS)

    Takahashi, Yuya; Chen, Lin; Okajima, Junnosuke; Iga, Yuka; Komiya, Atsuki; Maruyama, Shigenao

    2016-01-01

    Highlights: • Effective cooling design by super-/sub-sonic air flow in microchannels is proposed. • Microscale supersonic flows is successfully generated and examined. • Microchannel flow density field were visualized quantitatively by interferometer. • The bump design shows great potential of heat transfer enhancement in microscale. - Abstract: With the fast development of electronic systems and the ever-increasing demand of thermally “smart” design in space and aeronautic engineering, the heat transfer innovations and high heat flux challenges have become a hot topic for decades. This study is aimed at the effective cooling heat transfer design by super-/sub-sonic air flow in microscale channels for high heat flux devices. The design is based on the low temperature flows with supersonic expansion in microscale, which yields a compact and simple design. By careful microelectromechanical process, microscale straight and bumped channels (with simple arc curve) are fabricated and experimentally tested in this study. The microscale flow field and density distributions under new designs are visualized quantitatively by an advanced phase-shifting interferometer system, which results are then compared carefully with numerical simulations. In this study, large differences between the two designs in density distribution and temperature changes (around 50 K) are found. The high heat flux potential for supersonic microchannel flows is realized and discussion into detail. It is confirmed that the bump design contributes significantly to the heat transfer enhancement, which shows potential for future application in novel system designs.

  5. ON THE ORIGIN OF FANAROFF-RILEY CLASSIFICATION OF RADIO GALAXIES: DECELERATION OF SUPERSONIC RADIO LOBES

    International Nuclear Information System (INIS)

    Kawakatu, Nozomu; Kino, Motoki; Nagai, Hiroshi

    2009-01-01

    We argue that the origin of 'FRI/FRII dichotomy' - the division between Fanaroff-Riley class I (FRI) with subsonic lobes and class II (FRII) radio sources with supersonic lobes is sharp in the radio-optical luminosity plane (Owen-White diagram) - can be explained by the deceleration of advancing radio lobes. The deceleration is caused by the growth of the effective cross-sectional area of radio lobes. We derive the condition in which an initially supersonic lobe turns into a subsonic lobe, combining the ram pressure equilibrium between the hot spots and the ambient medium with the relation between 'the hot spot radius' and 'the linear size of radio sources' obtained from the radio observations. We find that the dividing line between the supersonic lobes and subsonic ones is determined by the ratio of the jet power L j to the number density of the ambient matter at the core radius of the host galaxy n-bar a . It is also found that the maximal ratio of (L j ,n-bar a ) exists and its value resides in (L j ,n-bar a ) max ∼10 44-47 er s -1 cm 3 , taking into account considerable uncertainties. This suggests that the maximal value (L j ,n-bar a ) max separates between FRIs and FRIIs.

  6. Nonlinear Dynamic Modeling and Controls Development for Supersonic Propulsion System Research

    Science.gov (United States)

    Connolly, Joseph W.; Kopasakis, George; Paxson, Daniel E.; Stuber, Eric; Woolwine, Kyle

    2012-01-01

    This paper covers the propulsion system component modeling and controls development of an integrated nonlinear dynamic simulation for an inlet and engine that can be used for an overall vehicle (APSE) model. The focus here is on developing a methodology for the propulsion model integration, which allows for controls design that prevents inlet instabilities and minimizes the thrust oscillation experienced by the vehicle. Limiting thrust oscillations will be critical to avoid exciting vehicle aeroelastic modes. Model development includes both inlet normal shock position control and engine rotor speed control for a potential supersonic commercial transport. A loop shaping control design process is used that has previously been developed for the engine and verified on linear models, while a simpler approach is used for the inlet control design. Verification of the modeling approach is conducted by simulating a two-dimensional bifurcated inlet and a representative J-85 jet engine previously used in a NASA supersonics project. Preliminary results are presented for the current supersonics project concept variable cycle turbofan engine design.

  7. Multi-fidelity and multi-disciplinary design optimization of supersonic business jets

    Science.gov (United States)

    Choi, Seongim

    Supersonic jets have been drawing great attention after the end of service for the Concorde was announced on April of 2003. It is believed, however, that civilian supersonic aircraft may make a viable return in the business jet market. This thesis focuses on the design optimization of feasible supersonic business jet configurations. Preliminary design techniques for mitigation of ground sonic boom are investigated while ensuring that all relevant disciplinary constraints are satisfied (including aerodynamic performance, propulsion, stability & control and structures.) In order to achieve reasonable confidence in the resulting designs, high-fidelity simulations are required, making the entire design process both expensive and complex. In order to minimize the computational cost, surrogate/approximate models are constructed using a hierarchy of different fidelity analysis tools including PASS, A502/Panair and Euler/NS codes. Direct search methods such as Genetic Algorithms (GAs) and a nonlinear SIMPLEX are employed to designs in searches of large and noisy design spaces. A local gradient-based search method can be combined with these global search methods for small modifications of candidate optimum designs. The Mesh Adaptive Direct Search (MADS) method can also be used to explore the design space using a solution-adaptive grid refinement approach. These hybrid approaches, both in search methodology and surrogate model construction, are shown to result in designs with reductions in sonic boom and improved aerodynamic performance.

  8. Evolution of the Orszag-Tang vortex system in a compressible medium. II - Supersonic flow

    Science.gov (United States)

    Picone, J. Michael; Dahlburg, Russell B.

    1991-01-01

    A study is presented on the effect of embedded supersonic flows and the resulting emerging shock waves on phenomena associated with MHD turbulence, including reconnection, the formation of current sheets and vortex structures, and the evolution of spatial and temporal correlations among physical variables. A two-dimensional model problem, the Orszag-Tang (1979) vortex system, is chosen, which involves decay from nonrandom initial conditions. The system is doubly periodic, and the initial conditions consist of single-mode solenoidal velocity and magnetic fields, each containing X points and O points. The initial mass density is flat, and the initial pressure fluctuations are incompressible, balancing the local forces for a magnetofluid of unit mass density. Results on the evolution of the local structure of the flow field, the global properties of the system, and spectral correlations are presented. The important dynamical properties and observational consequences of embedded supersonic regions and emerging shocks in the Orszag-Tang model of an MHD system undergoing reconnection are discussed. Conclusions are drawn regarding the effects of local supersonic regions on MHD turbulence.

  9. Increased Mach Number Capability for the NASA Glenn 10x10 Supersonic Wind Tunnel

    Science.gov (United States)

    Slater, J. W.; Saunders, J. D.

    2015-01-01

    Computational simulations and wind tunnel testing were conducted to explore the operation of the Abe Silverstein Supersonic Wind Tunnel at the NASA Glenn Research Center at test section Mach numbers above the current limit of Mach 3.5. An increased Mach number would enhance the capability for testing of supersonic and hypersonic propulsion systems. The focus of the explorations was on understanding the flow within the second throat of the tunnel, which is downstream of the test section and is where the supersonic flow decelerates to subsonic flow. Methods of computational fluid dynamics (CFD) were applied to provide details of the shock boundary layer structure and to estimate losses in total pressure. The CFD simulations indicated that the tunnel could be operated up to Mach 4.0 if the minimum width of the second throat was made smaller than that used for previous operation of the tunnel. Wind tunnel testing was able to confirm such operation of the tunnel at Mach 3.6 and 3.7 before a hydraulic failure caused a stop to the testing. CFD simulations performed after the wind tunnel testing showed good agreement with test data consisting of static pressures along the ceiling of the second throat. The CFD analyses showed increased shockwave boundary layer interactions, which was also observed as increased unsteadiness of dynamic pressures collected in the wind tunnel testing.

  10. An extended supersonic combustion model for the dynamic analysis of hypersonic vehicles

    Science.gov (United States)

    Bossard, J. A.; Peck, R. E.; Schmidt, D. K.

    1993-01-01

    The development of an advanced dynamic model for aeroelastic hypersonic vehicles powered by air breathing engines requires an adequate engine model. This report provides a discussion of some of the more important features of supersonic combustion and their relevance to the analysis and design of supersonic ramjet engines. Of particular interest are those aspects of combustion that impact the control of the process. Furthermore, the report summarizes efforts to enhance the aeropropulsive/aeroelastic dynamic model developed at the Aerospace Research Center of Arizona State University by focusing on combustion and improved modeling of this flow. The expanded supersonic combustor model described here has the capability to model the effects of friction, area change, and mass addition, in addition to the heat addition process. A comparison is made of the results from four cases: (1) heat addition only; (2) heat addition plus friction; (3) heat addition, friction, and area reduction, and (4) heat addition, friction, area reduction, and mass addition. The relative impact of these effects on the Mach number, static temperature, and static pressure distributions within the combustor are then shown. Finally, the effects of frozen versus equilibrium flow conditions within the exhaust plume is discussed.

  11. Pulsed, supersonic fuel jets-A review of their characteristics and potential for fuel injection

    International Nuclear Information System (INIS)

    Milton, B.E.; Pianthong, K.

    2005-01-01

    High pressure fuel injection has provided considerable benefits for diesel engines, substantially reducing smoke levels while increasing efficiency. Current maximum pressures provide jets that are at less than the sonic velocity of the compressed air in the cylinders at injection. It has been postulated that a further increase into the supersonic range may benefit the combustion process due to increased aerodynamic atomization and the presence of jet bow shock waves that provide higher temperatures around the fuel. Pulsed, supersonic injection may also be beneficial for scramjet engines. The current program is examining pulsed, supersonic jets from a fundamental viewpoint both experimentally and numerically. Shock wave structures have been viewed for jets ranging from 600 to 2400 m/s, velocity attenuation and penetration distance measured, different nozzle designs examined and autoignition experiments carried out. Inside the nozzle, numerical simulation using the Autodyne code has been used to support an analytic approach while in the spray, the FLUENT code has been used. While benefits have not yet been defined, it appears that some earlier claims regarding autoignition at atmospheric conditions were optimistic but that increased evaporation and mixing are probable. The higher jet velocities are likely to mean that wall interactions are increased and hence matching such injectors to engine size and airflow patterns will be important

  12. Advanced supersonic propulsion study, phase 2. [propulsion system performance, design analysis and technology assessment

    Science.gov (United States)

    Howlett, R. A.

    1975-01-01

    A continuation of the NASA/P and WA study to evaluate various types of propulsion systems for advanced commercial supersonic transports has resulted in the identification of two very promising engine concepts. They are the Variable Stream Control Engine which provides independent temperature and velocity control for two coannular exhaust streams, and a derivative of this engine, a Variable Cycle Engine that employs a rear flow-inverter valve to vary the bypass ratio of the cycle. Both concepts are based on advanced engine technology and have the potential for significant improvements in jet noise, exhaust emissions and economic characteristics relative to current technology supersonic engines. Extensive research and technology programs are required in several critical areas that are unique to these supersonic Variable Cycle Engines to realize these potential improvements. Parametric cycle and integration studies of conventional and Variable Cycle Engines are reviewed, features of the two most promising engine concepts are described, and critical technology requirements and required programs are summarized.

  13. Investigation of two pitot-static tubes at supersonic speeds

    Science.gov (United States)

    Hasel, Lowell E; Coletti, Donald E

    1948-01-01

    The results of tests at a Mach number of 1.94 of an ogives-nose cylindrical pitot-static tube and similar tests at Mach numbers of 1.93 and 1.62 of a service pitot-static tube to determine body static pressures and indicated Mach numbers are presented and discussed. The radial pressure distribution on the cylindrical bodies is compared with that calculated by an approximate theory.

  14. Feasibility and Diagnostic Accuracy of Supersonic Shear-Wave Elastography for the Assessment of Liver Stiffness and Liver Fibrosis in Children: A Pilot Study of 96 Patients.

    Science.gov (United States)

    Franchi-Abella, Stéphanie; Corno, Lucie; Gonzales, Emmanuel; Antoni, Guillemette; Fabre, Monique; Ducot, Béatrice; Pariente, Danièle; Gennisson, Jean-Luc; Tanter, Mickael; Corréas, Jean-Michel

    2016-02-01

    To evaluate the feasibility of using supersonic shear-wave elastography (SSWE) in children and normal values of liver stiffness with the use of control patients of different ages (from neonates to teenagers) and the diagnostic accuracy of supersonic shear wave elastography for assessing liver fibrosis by using the histologic scoring system as the reference method in patients with liver disease, with a special concern for early stages of fibrosis. The institutional review board approved this prospective study. Informed consent was obtained from parents and children older than 7 years. First, 51 healthy children (from neonate to 15 years) were analyzed as the control group, and univariate and multivariate comparisons were performed to study the effect of age, transducer, breathing condition, probe, and position on elasticity values. Next, 45 children (from 1 month to 17.2 years old) who underwent liver biopsy were analyzed. SSWE measurements were obtained in the same region of the liver as the biopsy specimens. Biopsy specimens were reviewed in a blinded manner by a pathologist with the use of METAVIR criteria. The areas under the receiver operating characteristics curve (AUCs) were calculated for patients with fibrosis stage F0 versus those with stage F1-F2, F2 or higher, F3 or higher, and F4 or higher. A successful rate of SSWE measurement was 100% in 96 patients, including neonates. Liver stiffness values were significantly higher when an SC6-1 probe (Aixplorer; SuperSonic Imagine SA, Aix-enProvence, France) was used than when an SL15-4 probe (Aixplorer) was used (mean ± standard deviation, 6.94 kPa ± 1.42 vs 5.96 kPa ± 1.31; P = .006). There was no influence of sex, the location of measurement, or respiratory status on liver elasticity values (P = .41-.93), although the power to detect such a difference was low. According to the degree of liver fibrosis at liver biopsy, 88.5%-96.8% of patients were correctly classified, with AUCs of 0.90-0.98 (95% confidence

  15. Electron ionization LC-MS with supersonic molecular beams--the new concept, benefits and applications.

    Science.gov (United States)

    Seemann, Boaz; Alon, Tal; Tsizin, Svetlana; Fialkov, Alexander B; Amirav, Aviv

    2015-11-01

    A new type of electron ionization LC-MS with supersonic molecular beams (EI-LC-MS with SMB) is described. This system and its operational methods are based on pneumatic spray formation of the LC liquid flow in a heated spray vaporization chamber, full sample thermal vaporization and subsequent electron ionization of vibrationally cold molecules in supersonic molecular beams. The vaporized sample compounds are transferred into a supersonic nozzle via a flow restrictor capillary. Consequently, while the pneumatic spray is formed and vaporized at above atmospheric pressure the supersonic nozzle backing pressure is about 0.15 Bar for the formation of supersonic molecular beams with vibrationally cold sample molecules without cluster formation with the solvent vapor. The sample compounds are ionized in a fly-though EI ion source as vibrationally cold molecules in the SMB, resulting in 'Cold EI' (EI of vibrationally cold molecules) mass spectra that exhibit the standard EI fragments combined with enhanced molecular ions. We evaluated the EI-LC-MS with SMB system and demonstrated its effectiveness in NIST library sample identification which is complemented with the availability of enhanced molecular ions. The EI-LC-MS with SMB system is characterized by linear response of five orders of magnitude and uniform compound independent response including for non-polar compounds. This feature improves sample quantitation that can be approximated without compound specific calibration. Cold EI, like EI, is free from ion suppression and/or enhancement effects (that plague ESI and/or APCI) which facilitate faster LC separation because full separation is not essential. The absence of ion suppression effects enables the exploration of fast flow injection MS-MS as an alternative to lengthy LC-MS analysis. These features are demonstrated in a few examples, and the analysis of the main ingredients of Cannabis on a few Cannabis flower extracts is demonstrated. Finally, the advantages of

  16. Low Density Supersonic Decelerator Flight Dynamics Test-1 Flight Design and Targeting

    Science.gov (United States)

    Ivanov, Mark

    2015-01-01

    NASA's Low Density Supersonic Decelerator (LDSD) program was established to identify, develop, and eventually qualify to Test [i.e. Technology] Readiness Level (TRL) - 6 aerodynamic decelerators for eventual use on Mars. Through comprehensive Mars application studies, two distinct Supersonic Inflatable Aerodynamic Decelerator (SIAD) designs were chosen that afforded the optimum balance of benefit, cost, and development risk. In addition, a Supersonic Disk Sail (SSDS) parachute design was chosen that satisfied the same criteria. The final phase of the multi-tiered qualification process involves Earth Supersonic Flight Dynamics Tests (SFDTs) within environmental conditions similar to those that would be experienced during a Mars Entry, Descent, and Landing (EDL) mission. The first of these flight tests (i.e. SFDT-1) was completed on June 28, 2014 with two more tests scheduled for the summer of 2015 and 2016, respectively. The basic flight design for all the SFDT flights is for the SFDT test vehicle to be ferried to a float altitude of 120 kilo-feet by a 34 thousand cubic feet (Mcf) heavy lift helium balloon. Once float altitude is reached, the test vehicle is released from the balloon, spun-up for stability, and accelerated to supersonic speeds using a Star48 solid rocket motor. After burnout of the Star48 motor the vehicle decelerates to pre-flight selected test conditions for the deployment of the SIAD system. After further deceleration with the SIAD deployed, the SSDS parachute is then deployed stressing the performance of the parachute in the wake of the SIAD augmented blunt body. The test vehicle/SIAD/parachute system then descends to splashdown in the Pacific Ocean for eventual recovery. This paper will discuss the development of both the test vehicle and the trajectory sequence including design trade-offs resulting from the interaction of both engineering efforts. In addition, the SFDT-1 nominal trajectory design and associated sensitivities will be discussed

  17. A first-order Green's function approach to supersonic oscillatory flow: A mixed analytic and numeric treatment

    Science.gov (United States)

    Freedman, M. I.; Sipcic, S.; Tseng, K.

    1985-01-01

    A frequency domain Green's Function Method for unsteady supersonic potential flow around complex aircraft configurations is presented. The focus is on the supersonic range wherein the linear potential flow assumption is valid. In this range the effects of the nonlinear terms in the unsteady supersonic compressible velocity potential equation are negligible and therefore these terms will be omitted. The Green's function method is employed in order to convert the potential flow differential equation into an integral one. This integral equation is then discretized, through standard finite element technique, to yield a linear algebraic system of equations relating the unknown potential to its prescribed co-normalwash (boundary condition) on the surface of the aircraft. The arbitrary complex aircraft configuration (e.g., finite-thickness wing, wing-body-tail) is discretized into hyperboloidal (twisted quadrilateral) panels. The potential and co-normalwash are assumed to vary linearly within each panel. The long range goal is to develop a comprehensive theory for unsteady supersonic potential aerodynamic which is capable of yielding accurate results even in the low supersonic (i.e., high transonic) range.

  18. Magnetic Field Calculator

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Magnetic Field Calculator will calculate the total magnetic field, including components (declination, inclination, horizontal intensity, northerly intensity,...

  19. Supersonic shear imaging for the diagnosis of liver fibrosis and portal hypertension in liver diseases: a meta-analysis.

    Science.gov (United States)

    Deng, Han; Qi, Xingshun; Zhang, Tiansong; Qi, Xiaolong; Yoshida, Eric M; Guo, Xiaozhong

    2018-01-01

    The meta-analysis aimed to summarize the technical success rate of supersonic shear imaging (SSI) and to evaluate the diagnostic performance of liver and spleen stiffness measurement (LSM and SSM) with SSI for the detection of liver fibrosis, portal hypertension, and gastroesophageal varices in liver diseases. PubMed, EMBASE, and Cochrane Library databases were searched. Technical success rate of SSI was pooled. Area under curve (AUC), sensitivity, and specificity with corresponding 95% confidence interval (CI) were calculated. Included studies regarding the diagnostic performance of SSI for liver fibrosis, portal hypertension, and esophageal varices numbered 28, 4, and 4 respectively. The pooled technical success rates of LSM and SSM were 95.3% and 75.5%, respectively. The AUC, sensitivity, and specificity of LSM/SSM for different stages of liver fibrosis were 0.85-0.94, 0.7-0.89, and 0.82-0.92, respectively. The AUC, sensitivity, and specificity of LSM were 0.84 (95%CI = 0.8-0.86), 0.79 (95%CI = 0.7-0.85), and 0.82 (95%CI = 0.72-0.88) for clinically significant portal hypertension, 0.85 (95%CI = 0.82-0.88), 0.8 (95%CI = 0.68-0.88), and 0.8 (95%CI = 0.6-0.92) for any varices, and 0.86 (95%CI = 0.83-0.89), 0.86 (95%CI = 0.76-0.92), and 0.61 (95%CI = 0.35-0.83) for high-risk varices, respectively. LSM with SSI had a high diagnostic accuracy for liver fibrosis, but a moderate diagnostic accuracy for portal hypertension and esophageal varices.

  20. a Time-Dependent Three-Dimensional Numerical Study of Supersonic Rectangular Jet Flow and Noise Using the Full Navier-Stokes Equations.

    Science.gov (United States)

    Chyczewski, Thomas Stanley, Jr.

    factors (such as initial disturbance amplitude, corner vortices and modal excitation) that can significantly influence the jet development. A comprehensive analysis of the effect of these factors is provided. The method has been implemented and optimized on the CM-5 using the data parallel paradigm. These optimizations are quite effective and result in an efficient parallel algorithm. The code is written in CMFortran, which is a dialect of High Performance Fortran (HPF), and can be easily ported to the latest generation parallel processors. The supersonic flow from a cold, ideally expanded rectangular orifice is calculated to validate the code. The geometry (jet aspect ratio of 3) and flow conditions (M _{jet}=1.54,Re_{jet}=25,000) are selected to match those of a rectangular jet experiment that has recently concluded at The Pennsylvania State University. Detailed information on the experimental setup as well as experimental results have been provided. The results presented in this thesis indicate that the direct simulation approach is capable of predicting many of the features of supersonic rectangular jets. This includes the evolution of large scale turbulent structures and the noise they radiate to the far field.

  1. High angle of attack aerodynamics subsonic, transonic, and supersonic flows

    CERN Document Server

    Rom, Josef

    1992-01-01

    The aerodynamics of aircraft at high angles of attack is a subject which is being pursued diligently, because the modern agile fighter aircraft and many of the current generation of missiles must perform well at very high incidence, near and beyond stall. However, a comprehensive presentation of the methods and results applicable to the studies of the complex aerodynamics at high angle of attack has not been covered in monographs or textbooks. This book is not the usual textbook in that it goes beyond just presenting the basic theoretical and experimental know-how, since it contains reference material to practical calculation methods and technical and experimental results which can be useful to the practicing aerospace engineers and scientists. It can certainly be used as a text and reference book for graduate courses on subjects related to high angles of attack aerodynamics and for topics related to three-dimensional separation in viscous flow courses. In addition, the book is addressed to the aerodynamicist...

  2. Calculation of afterbody flows with a composite velocity formulation

    Science.gov (United States)

    Swanson, R. C.; Rubin, S. G.; Khosla, P. K.

    1983-01-01

    A recently developed technique for numerical solution of the Navier-Stokes equations for subsonic, laminar flows is investigated. It is extended here to allow for the computation of transonic and turbulent flows. The basic approach involves a multiplicative composite of the appropriate velocity representations for the inviscid and viscous flow regions. The resulting equations are structured so that far from the surface of the body the momentum equations lead to the Bernoulli equation for the pressure, while the continuity equation reduces to the familiar potential equation. Close to the body surface, the governing equations and solution techniques are characteristic of those describing interacting boundary layers. The velocity components are computed with a coupled strongly implicity procedure. For transonic flows the artificial compressibility method is used to treat supersonic regions. Calculations are made for both laminar and turbulent flows over axisymmetric afterbody configurations. Present results compare favorably with other numerical solutions and/or experimental data.

  3. Transition due to streamwise streaks in a supersonic flat plate boundary layer

    Science.gov (United States)

    Paredes, Pedro; Choudhari, Meelan M.; Li, Fei

    2016-12-01

    Transition induced by stationary streaks undergoing transient growth in a supersonic flat plate boundary layer flow is studied using numerical computations. While the possibility of strong transient growth of small-amplitude stationary perturbations in supersonic boundary layer flows has been demonstrated in previous works, its relation to laminar-turbulent transition cannot be established within the framework of linear disturbances. Therefore, this paper investigates the nonlinear evolution of initially linear optimal disturbances that evolve into finite amplitude streaks in the downstream region, and then studies the modal instability of those streaks as a likely cause for the onset of bypass transition. The nonmodal evolution of linearly optimal stationary perturbations in a supersonic, Mach 3 flat plate boundary layer is computed via the nonlinear plane-marching parabolized stability equations (PSE) for stationary perturbations, or equivalently, the perturbation form of parabolized Navier-Stokes equations. To assess the effect of the nonlinear finite-amplitude streaks on transition, the linear form of plane-marching PSE is used to investigate the instability of the boundary layer flow modified by the spanwise periodic streaks. The onset of transition is estimated using an N -factor criterion based on modal amplification of the secondary instabilities of the streaks. In the absence of transient growth disturbances, first mode instabilities in a Mach 3, zero pressure gradient boundary layer reach N =10 at Rex≈107 . However, secondary instability modes of the stationary streaks undergoing transient growth are able to achieve the same N -factor at Rex<2 ×106 when the initial streak amplitude is sufficiently large. In contrast to the streak instabilities in incompressible flows, subharmonic instability modes with twice the fundamental spanwise wavelength of the streaks are found to have higher amplification ratios than the streak instabilities at fundamental

  4. Aerodynamic shape optimization directed toward a supersonic transport using sensitivity analysis

    Science.gov (United States)

    Baysal, Oktay

    1995-01-01

    This investigation was conducted from March 1994 to August 1995, primarily, to extend and implement the previously developed aerodynamic design optimization methodologies for the problems related to a supersonic transport design. These methods had demonstrated promise to improve the designs (more specifically, the shape) of aerodynamic surfaces, by coupling optimization algorithms (OA) with Computational Fluid Dynamics (CFD) algorithms via sensitivity analyses (SA) with surface definition methods from Computer Aided Design (CAD). The present extensions of this method and their supersonic implementations have produced wing section designs, delta wing designs, cranked-delta wing designs, and nacelle designs, all of which have been reported in the open literature. Despite the fact that these configurations were highly simplified to be of any practical or commercial use, they served the algorithmic and proof-of-concept objectives of the study very well. The primary cause for the configurational simplifications, other than the usual simplify-to-study the fundamentals reason, were the premature closing of the project. Only after the first of the originally intended three-year term, both the funds and the computer resources supporting the project were abruptly cut due to their severe shortages at the funding agency. Nonetheless, it was shown that the extended methodologies could be viable options in optimizing the design of not only an isolated single-component configuration, but also a multiple-component configuration in supersonic and viscous flow. This allowed designing with the mutual interference of the components being one of the constraints all along the evolution of the shapes.

  5. Vortex Generators in a Streamline-Traced, External-Compression Supersonic Inlet

    Science.gov (United States)

    Baydar, Ezgihan; Lu, Frank K.; Slater, John W.; Trefny, Charles J.

    2017-01-01

    Vortex generators within a streamline-traced, external-compression supersonic inlet for Mach 1.66 were investigated to determine their ability to increase total pressure recovery and reduce total pressure distortion. The vortex generators studied were rectangular vanes arranged in counter-rotating and co-rotating arrays. The vane geometric factors of interest included height, length, spacing, angle-of-incidence, and positions upstream and downstream of the inlet terminal shock. The flow through the inlet was simulated numerically through the solution of the steady-state, Reynolds-averaged Navier-Stokes equations on multi-block, structured grids using the Wind-US flow solver. The vanes were simulated using a vortex generator model. The inlet performance was characterized by the inlet total pressure recovery and the radial and circumferential total pressure distortion indices at the engine face. Design of experiments and statistical analysis methods were applied to quantify the effect of the geometric factors of the vanes and search for optimal vane arrays. Co-rotating vane arrays with negative angles-of-incidence positioned on the supersonic diffuser were effective in sweeping low-momentum flow from the top toward the sides of the subsonic diffuser. This distributed the low-momentum flow more evenly about the circumference of the subsonic diffuser and reduced distortion. Co-rotating vane arrays with negative angles-of-incidence or counter-rotating vane arrays positioned downstream of the terminal shock were effective in mixing higher-momentum flow with lower-momentum flow to increase recovery and decrease distortion. A strategy of combining a co-rotating vane array on the supersonic diffuser with a counter-rotating vane array on the subsonic diffuser was effective in increasing recovery and reducing distortion.

  6. Supersonic beams at high particle densities: model description beyond the ideal gas approximation.

    Science.gov (United States)

    Christen, Wolfgang; Rademann, Klaus; Even, Uzi

    2010-10-28

    Supersonic molecular beams constitute a very powerful technique in modern chemical physics. They offer several unique features such as a directed, collision-free flow of particles, very high luminosity, and an unsurpassed strong adiabatic cooling during the jet expansion. While it is generally recognized that their maximum flow velocity depends on the molecular weight and the temperature of the working fluid in the stagnation reservoir, not a lot is known on the effects of elevated particle densities. Frequently, the characteristics of supersonic beams are treated in diverse approximations of an ideal gas expansion. In these simplified model descriptions, the real gas character of fluid systems is ignored, although particle associations are responsible for fundamental processes such as the formation of clusters, both in the reservoir at increased densities and during the jet expansion. In this contribution, the various assumptions of ideal gas treatments of supersonic beams and their shortcomings are reviewed. It is shown in detail that a straightforward thermodynamic approach considering the initial and final enthalpy is capable of characterizing the terminal mean beam velocity, even at the liquid-vapor phase boundary and the critical point. Fluid properties are obtained using the most accurate equations of state available at present. This procedure provides the opportunity to naturally include the dramatic effects of nonideal gas behavior for a large variety of fluid systems. Besides the prediction of the terminal flow velocity, thermodynamic models of isentropic jet expansions permit an estimate of the upper limit of the beam temperature and the amount of condensation in the beam. These descriptions can even be extended to include spinodal decomposition processes, thus providing a generally applicable tool for investigating the two-phase region of high supersaturations not easily accessible otherwise.

  7. PIV Measurements of Supersonic Internally-Mixed Dual-Stream Jets

    Science.gov (United States)

    Bridges, James E.; Wernet, Mark P.

    2012-01-01

    While externally mixed, or separate flow, nozzle systems are most common in high bypass-ratio aircraft, they are not as attractive for use in lower bypass-ratio systems and on aircraft that will fly supersonically. The noise of such propulsion systems is also dominated by jet noise, making the study and noise reduction of these exhaust systems very important, both for military aircraft and future civilian supersonic aircraft. This paper presents particle image velocimetry of internally mixed nozzle with different area ratios between core and bypass, and nozzles that are ideally expanded and convergent. Such configurations independently control the geometry of the internal mixing layer and of the external shock structure. These allow exploration of the impact of shocks on the turbulent mixing layers, the impact of bypass ratio on broadband shock noise and mixing noise, and the impact of temperature on the turbulent flow field. At the 2009 AIAA/CEAS Aeroacoustics Conference the authors presented data and analysis from a series of tests that looked at the acoustics of supersonic jets from internally mixed nozzles. In that paper the broadband shock and mixing noise components of the jet noise were independently manipulated by holding Mach number constant while varying bypass ratio and jet temperature. Significant portions of that analysis was predicated on assumptions regarding the flow fields of these jets, both shock structure and turbulence. In this paper we add to that analysis by presenting particle image velocimetry measurements of the flow fields of many of those jets. In addition, the turbulent velocity data documented here will be very useful for validation of computational flow codes that are being developed to design advanced nozzles for future aircraft.

  8. Numerical simulation of the generation mechanism of axisymmetric supersonic jet screech tones

    Science.gov (United States)

    Li, X. D.; Gao, J. H.

    2005-08-01

    In this paper an axisymmetric computational aeroacoustic procedure is developed to investigate the generation mechanism of axisymmetric supersonic jet screech tones. The axisymmetric Navier-Stokes equations and the two equations standard k-ɛ turbulence model modified by Turpin and Troyes ["Validation of a two-equation turbulence model for axisymmetric reacting and non-reaction flows," AIAA Paper No. 2000-3463 (2000)] are solved in the generalized curvilinear coordinate system. A generalized wall function is applied in the nozzle exit wall region. The dispersion-relation-preserving scheme is applied for space discretization. The 2N storage low-dissipation and low-dispersion Runge-Kutta scheme is employed for time integration. Much attention is paid to far-field boundary conditions and turbulence model. The underexpanded axisymmetric supersonic jet screech tones are simulated over the Mach number from 1.05 to 1.2. Numerical results are presented and compared with the experimental data by other researchers. The simulated wavelengths of A0, A1, A2, and B modes and part of simulated amplitudes agree very well with the measurement data by Ponton and Seiner ["The effects of nozzle exit lip thickness on plume resonance," J. Sound Vib. 154, 531 (1992)]. In particular, the phenomena of modes jumping have been captured correctly although the numerical procedure has to be improved to predict the amplitudes of supersonic jet screech tones more accurately. Furthermore, the phenomena of shock motions are analyzed. The predicted splitting and combination of shock cells are similar with the experimental observations of Panda ["Shock oscillation in underexpanded screeching jets," J. Fluid. Mech. 363, 173 (1998)]. Finally, the receptivity process is numerically studied and analyzed. It is shown that the receptivity zone is associated with the initial thin shear layer, and the incoming and reflected sound waves.

  9. CFD calculations on the unsteady aerodynamic characteristics of a tilt-rotor in a conversion mode

    Directory of Open Access Journals (Sweden)

    Li Peng

    2015-12-01

    Full Text Available In order to calculate the unsteady aerodynamic characteristics of a tilt-rotor in a conversion mode, a virtual blade model (VBM and an real blade model (RBM are established respectively. A new multi-layer moving-embedded grid technique is proposed to reduce the numerical dissipation of the tilt-rotor wake in a conversion mode. In this method, a grid system generated abound the rotor accounts for rigid blade motions, and a new searching scheme named adaptive inverse map (AIM is established to search corresponding donor elements in the present moving-embedded grid system to translate information among the different computational zones. A dual-time method is employed to fulfill unsteady calculations on the flowfield of the tilt-rotor, and a second-order centered difference scheme considering artificial viscosity is used to calculate the flux. In order to improve the computing efficiency, the single program multiple data (SPMD model parallel acceleration technology is adopted, according to the characteristic of the current grid system. The lift and drag coefficients of an NACA0012 airfoil, the dynamic pressure distributions below a typical rotor plane, and the sectional pressure distributions on a three-bladed Branum–Tung tilt-rotor in hover flight are calculated respectively, and the present VBM and RBM are validated by comparing the calculated results with available experimental data. Then, unsteady aerodynamic forces and flowfields of an XV-15 tilt-rotor in different modes, such as a fixed conversion mode at different tilt angles (15°, 30°, 60° and a whole conversion mode which converses from 0° to 90°, are numerically simulated by the VBM and RBM respectively. By analyses and comparisons on the simulated results of unsteady aerodynamic forces of the tilt-rotor in different modes, some meaningful conclusions about distorted blade-tip vortex distribution and unsteady aerodynamic force variation in a conversion mode are obtained, and these

  10. Interaction of a supersonic plasma jet with a coaxial dipole magnetic field

    International Nuclear Information System (INIS)

    Landes, K.

    1975-01-01

    A low pressure plasma jet of considerable conductivity can be influenced by a magnetic field. On the other hand the influencing magnetic field is changed by currents induced in the plasma jet. New astrophysical examples of suchlike interaction have been found in the investigation of the moon, where the partially not currentfree solar wind is influenced by locally confined magnetic fields. In the experiment reported, the interaction of a supersonic plasma jet with a coaxial, dipole-shaped magnetic field is investigated. A current is superimposed to the plasma jet. (Auth.)

  11. Supersonic propagation of ionization waves in an underdense, laser-produced plasma

    International Nuclear Information System (INIS)

    Constantin, C.; Back, C.A.; Fournier, K.B.; Gregori, G.; Landen, O.L.; Glenzer, S.H.; Dewald, E.L.; Miller, M.C.

    2005-01-01

    A laser-driven supersonic ionization wave propagating through a millimeter-scale plasma of subcritical density up to 2-3 keV electron temperatures was observed. Propagation velocities initially ten times the sound speed were measured by means of time-resolved x-ray imaging diagnostics. The measured ionization wave trajectory is modeled analytically and by a two-dimensional radiation-hydrodynamics code. The comparison to the modeling suggests that nonlocal heat transport effects may contribute to the attenuation of the heat-wave propagation

  12. Supersonic N-Crowdions in a Two-Dimensional Morse Crystal

    Science.gov (United States)

    Dmitriev, S. V.; Korznikova, E. A.; Chetverikov, A. P.

    2018-03-01

    An interstitial atom placed in a close-packed atomic row of a crystal is called crowdion. Such defects are highly mobile; they can move along the row, transferring mass and energy. We generalize the concept of a classical supersonic crowdion to an N-crowdion in which not one but N atoms move simultaneously with a high velocity. Using molecular dynamics simulations for a close-packed two-dimensional Morse crystal, we show that N-crowdions transfer mass much more efficiently, because they are capable of covering large distances while having a lower total energy than that of a classical 1-crowdion.

  13. Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 3: Sections 12 through 14

    Science.gov (United States)

    Sakata, I. F.; Davis, G. W.

    1975-01-01

    The design of an economically viable supersonic cruise aircraft requires the lowest attainable structural-mass fraction commensurate with the selected near-term structural material technology. To achieve this goal of minimum structural-mass fraction, various combinations of promising wing and fuselage primary structure were analyzed for the load-temperature environment applicable to the arrow wing configuration. This analysis was conducted in accordance with the design criteria specified and included extensive use of computer-aided analytical methods to screen the candidate concepts and select the most promising concepts for the in-depth structural analysis.

  14. Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 4: Sections 15 through 21

    Science.gov (United States)

    Sakata, I. F.; Davis, G. W.

    1975-01-01

    The analyses performed to provide structural mass estimates for the arrow wing supersonic cruise aircraft are presented. To realize the full potential for structural mass reduction, a spectrum of approaches for the wing and fuselage primary structure design were investigated. The objective was: (1) to assess the relative merits of various structural arrangements, concepts, and materials; (2) to select the structural approach best suited for the Mach 2.7 environment; and (3) to provide construction details and structural mass estimates based on in-depth structural design studies. Production costs, propulsion-airframe integration, and advanced technology assessment are included.

  15. Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 2: Sections 7 through 11

    Science.gov (United States)

    Sakata, I. F.; Davis, G. W.

    1975-01-01

    The materials and advanced producibility methods that offer potential structural mass savings in the design of the primary structure for a supersonic cruise aircraft are identified and reported. A summary of the materials and fabrication techniques selected for this analytical effort is presented. Both metallic and composite material systems were selected for application to a near-term start-of-design technology aircraft. Selective reinforcement of the basic metallic structure was considered as the appropriate level of composite application for the near-term design.

  16. Aerodynamic Interaction between Delta Wing and Hemisphere-Cylinder in Supersonic Flow

    Science.gov (United States)

    Nishino, Atsuhiro; Ishikawa, Takahumi; Nakamura, Yoshiaki

    As future space vehicles, Reusable Launch Vehicle (RLV) needs to be developed, where there are two kinds of RLV: Single Stage To Orbit (SSTO) and Two Stage To Orbit (TSTO). In the latter case, the shock/shock interaction and shock/boundary layer interaction play a key role. In the present study, we focus on the supersonic flow field with aerodynamic interaction between a delta wing and a hemisphere-cylinder, which imitate a TSTO, where the clearance, h, between the delta wing and hemisphere-cylinder is a key parameter. As a result, complicated flow patterns were made clear, including separation bubbles.

  17. Performance characterization of Ni60-WC coating on steel processed with supersonic laser deposition

    Directory of Open Access Journals (Sweden)

    Fang Luo

    2015-03-01

    Full Text Available Ni60-WC particles are used to improve the wear resistance of hard-facing steel due to their high hardness. An emerging technology that combines laser with cold spraying to deposit the hard-facing coatings is known as supersonic laser deposition. In this study, Ni60-WC is deposited on low-carbon steel using SLD. The microstructure and performance of the coatings are investigated through SEM, optical microscopy, EDS, XRD, microhardness and pin-on-disc wear tests. The experimental results of the coating processed with the optimal parameters are compared to those of the coating deposited using laser cladding.

  18. Kolmogorov-like spectra in decaying three-dimensional supersonic flows

    International Nuclear Information System (INIS)

    Porter, D.H.; Pouquet, A.; Woodward, P.R.

    1994-01-01

    A numerical simulation of decaying supersonic turbulence using the piecewise parabolic method (PPM) algorithm on a computational mesh of 512 3 zones indicates that, once the solenoidal part of the velocity field, representing vortical motions, is fully developed and has reached a self-similar regime, a velocity spectrum compatible with that predicted by the classical theory of Kolmogorov develops. It is followed by a domain with a shallower spectrum. A convergence study is presented to support these assertions. The formation, structure, and evolution of slip surfaces and vortex tubes are presented in terms of perspective volume renderings of fields in physical space

  19. Influence of probe geometry on pitot-probe displacement in supersonic turbulent flow

    Science.gov (United States)

    Allen, J. M.

    1975-01-01

    An experiment was conducted to determine the varying effects of six different probe-tip and support-shaft configurations on pitot tube displacement. The study was stimulated by discrepancies between supersonic wind-tunnel tests conducted by Wilson and Young (1949) and Allen (1972). Wilson (1973) had concluded that these discrepancies were caused by differences in probe geometry. It is shown that in fact, no major differences in profiles of streamwise velocity over streamwise velocity at boundary-layer edge vs normal coordinate over boundary-layer total thickness result from geometry. The true cause of the discrepancies, however, remains to be discovered.

  20. Experimental evidence for collisional shock formation via two obliquely merging supersonic plasma jets

    Energy Technology Data Exchange (ETDEWEB)

    Merritt, Elizabeth C., E-mail: emerritt@lanl.gov; Adams, Colin S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); University of New Mexico, Albuquerque, New Mexico 87131 (United States); Moser, Auna L.; Hsu, Scott C., E-mail: scotthsu@lanl.gov; Dunn, John P.; Miguel Holgado, A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Gilmore, Mark A. [University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2014-05-15

    We report spatially resolved measurements of the oblique merging of two supersonic laboratory plasma jets. The jets are formed and launched by pulsed-power-driven railguns using injected argon, and have electron density ∼10{sup 14} cm{sup −3}, electron temperature ≈1.4 eV, ionization fraction near unity, and velocity ≈40 km/s just prior to merging. The jet merging produces a few-cm-thick stagnation layer, as observed in both fast-framing camera images and multi-chord interferometer data, consistent with collisional shock formation [E. C. Merritt et al., Phys. Rev. Lett. 111, 085003 (2013)].

  1. Pressure Measurement in Supersonic Air Flow by Differential Absorptive Laser-Induced Thermal Acoustics

    Science.gov (United States)

    Hart, Roger C.; Herring, Gregory C.; Balla, Robert J.

    2007-01-01

    Nonintrusive, off-body flow barometry in Mach-2 airflow has been demonstrated in a large-scale supersonic wind tunnel using seedless laser-induced thermal acoustics (LITA). The static pressure of the gas flow is determined with a novel differential absorption measurement of the ultrasonic sound produced by the LITA pump process. Simultaneously, stream-wise velocity and static gas temperature of the same spatially-resolved sample volume were measured with this nonresonant time-averaged LITA technique. Mach number, temperature and pressure have 0.2%, 0.4%, and 4% rms agreement, respectively, in comparison with known free-stream conditions.

  2. Computations of the Magnus effect for slender bodies in supersonic flow

    Science.gov (United States)

    Sturek, W. B.; Schiff, L. B.

    1980-01-01

    A recently reported Parabolized Navier-Stokes code has been employed to compute the supersonic flow field about spinning cone, ogive-cylinder, and boattailed bodies of revolution at moderate incidence. The computations were performed for flow conditions where extensive measurements for wall pressure, boundary layer velocity profiles and Magnus force had been obtained. Comparisons between the computational results and experiment indicate excellent agreement for angles of attack up to six degrees. The comparisons for Magnus effects show that the code accurately predicts the effects of body shape and Mach number for the selected models for Mach numbers in the range of 2-4.

  3. The Experimental Measurement of Aerodynamic Heating About Complex Shapes at Supersonic Mach Numbers

    Science.gov (United States)

    Neumann, Richard D.; Freeman, Delma C.

    2011-01-01

    In 2008 a wind tunnel test program was implemented to update the experimental data available for predicting protuberance heating at supersonic Mach numbers. For this test the Langley Unitary Wind Tunnel was also used. The significant differences for this current test were the advances in the state-of-the-art in model design, fabrication techniques, instrumentation and data acquisition capabilities. This current paper provides a focused discussion of the results of an in depth analysis of unique measurements of recovery temperature obtained during the test.

  4. Utilization of an arc-heated jet for production of supersonic seeded beams of atomic nitrogen

    International Nuclear Information System (INIS)

    Bickes, R.W. Jr.; Newton, K.R.; Herrmann, J.M.; Bernstein, R.B.

    1976-01-01

    Intense supersonic beams of atomic nitrogen (>10 17 atoms sr -1 sec -1 ) have been produced from the dissociation of N 2 in an Ar arc (at temperatures in excess of 6000 K) using the arc-heated nozzle beam source of Young, Rodgers, and Knuth. Experiments characterizing the N 2 dissociation and the translational energies of the N, N 2 , and Ar components in the beams are described. Evidence is presented for the formation of atomic C as well as C 2 and CH from the pyrolysis of CH 4 and C 2 H 4 in the Ar arc

  5. Redundant actuator development study. [flight control systems for supersonic transport aircraft

    Science.gov (United States)

    Ryder, D. R.

    1973-01-01

    Current and past supersonic transport configurations are reviewed to assess redundancy requirements for future airplane control systems. Secondary actuators used in stability augmentation systems will probably be the most critical actuator application and require the highest level of redundancy. Two methods of actuator redundancy mechanization have been recommended for further study. Math models of the recommended systems have been developed for use in future computer simulations. A long range plan has been formulated for actuator hardware development and testing in conjunction with the NASA Flight Simulator for Advanced Aircraft.

  6. CO2 flowrate calculator

    International Nuclear Information System (INIS)

    Carossi, Jean-Claude

    1969-02-01

    A CO 2 flowrate calculator has been designed for measuring and recording the gas flow in the loops of Pegase reactor. The analog calculator applies, at every moment, Bernoulli's formula to the values that characterize the carbon dioxide flow through a nozzle. The calculator electronics is described (it includes a sampling calculator and a two-variable function generator), with its amplifiers, triggers, interpolator, multiplier, etc. Calculator operation and setting are presented

  7. Formation of atomic clusters through the laser ablation of refractory materials in a supersonic molecular beam source

    International Nuclear Information System (INIS)

    Haufler, R.E.; Puretzky, A.A.; Compton, R.N.

    1993-01-01

    Concepts which guide the design of atomic cluster supersonic beam sources have been developed. These ideas are founded on the knowledge of laser ablation dynamics and are structured in order to take advantage of certain features of the ablation event. Some of the drawbacks of previous cluster source designs become apparent when the sequence of events following laser ablation are clarified. Key features of the new cluster source design include control of the cluster size distribution, uniform performance with a variety of solid materials and elements, high beam intensity, and significant removal of internal energy during the supersonic expansion

  8. Method and System for Weakening Shock Wave Strength at Leading Edge Surfaces of Vehicle in Supersonic Atmospheric Flight

    Science.gov (United States)

    Daso, Endwell O. (Inventor); Pritchett, Victor E., II (Inventor); Wang, Ten-See (Inventor); Farr, Rebecca Ann (Inventor); Auslender, Aaron Howard (Inventor); Blankson, Isaiah M. (Inventor); Plotkin, Kenneth J. (Inventor)

    2015-01-01

    A method and system are provided to weaken shock wave strength at leading edge surfaces of a vehicle in atmospheric flight. One or more flight-related attribute sensed along a vehicle's outer mold line are used to control the injection of a non-heated, non-plasma-producing gas into a local external flowfield of the vehicle from at least one leading-edge surface location along the vehicle's outer mold line. Pressure and/or mass flow rate of the gas so-injected is adjusted in order to cause a Rankine-Hugoniot Jump Condition along the vehicle's outer mold line to be violated.

  9. Results from flamelet and non-flamelet models for supersonic combustion

    Science.gov (United States)

    Ladeinde, Foluso; Li, Wenhai

    2017-11-01

    Air-breathing propulsion systems (scramjets) have been identified as a viable alternative to rocket engines for improved efficiency. A scramjet engine, which operates at flight Mach numbers around 7 or above, is characterized by the existence of supersonic flow conditions in the combustor. In a dual-mode scramjet, this phenomenon is possible because of the relatively low value of the equivalence ratio and high stagnation temperature, which, together, inhibits thermal choking downstream of transverse injectors. The flamelet method has been our choice for turbulence-combustion interaction modeling and we have extended the basic approach in several dimensions, with a focus on the way the pressure and progress variable are modeled. Improved results have been obtained. We have also examined non-flamelet models, including laminar chemistry (QL), eddy dissipation concept (EDC), and partially-stirred reactor (PaSR). The pressure/progress variable-corrected simulations give better results compared with the original model, with reaction rates that are lower than those from EDC and PaSR. In general, QL tends to over-predict the reaction rate for the supersonic combustion problems investigated in our work.

  10. Effect of outer stagnation pressure on jet structure in supersonic coaxial jet

    International Nuclear Information System (INIS)

    Kim, Myoung Jong; Woo, Sang Woo; Lee, Byeong Eun; Kwon, Soon Bum

    2001-01-01

    The characteristics of dual coaxial jet which composed of inner supersonic nozzle of 26500 in constant expansion rate with 1.91 design Mach number and outer converging one with 40 .deg. C converging angle with the variation of outer nozzle stagnation pressure are experimentally investigated in this paper. In which the stagnation pressure for the inner supersonic nozzle is 750kPa thus, the inner jet leaving the nozzle is slightly underexpanded. The plenum pressure of outer nozzle are varied from 200 to 600kPa. Flow visualizations by shadowgraph method, impact pressure and centerline static pressure measurements of dual coaxial jet are presented. The results show that the presence of outer jet affects significantly the structures and pressure distributions of inner jet. And outer jet causes Mach disk which does not appear for the case of single jet stream. As the stagnation pressure of outer jet increases, impact pressure undulation is severe, but the average impact pressure keeps high far downstream

  11. Equations for the kinetic modeling of supersonically flowing electrically excited lasers

    International Nuclear Information System (INIS)

    Lind, R.C.

    1973-01-01

    The equations for the kinetic modeling of a supersonically flowing electrically excited laser system are presented. The work focuses on the use of diatomic gases, in particular carbon monoxide mixtures. The equations presented include the vibrational rate equation which describes the vibrational population distribution, the electron, ion and electronic level rate equations, the gasdynamic equations for an ionized gas in the presence of an applied electric field, and the free electron Boltzmann equation including flow and gradient coupling terms. The model developed accounts for vibration--vibration collisions, vibration-translation collisions, electron-molecule inelastic excitation and superelastic de-excitation collisions, charge particle collisions, ionization and three body recombination collisions, elastic collisions, and radiative decay, all of which take place in such a system. A simplified form of the free electron Boltzmann equation is developed and discussed with emphasis placed on its coupling with the supersonic flow. A brief description of a possible solution procedure for the set of coupled equations is discussed

  12. Impingement of water droplets on wedges and diamond airfoils at supersonic speeds

    Science.gov (United States)

    Serafini, John S

    1953-01-01

    An analytical solution has been obtained for the equations of motion of water droplets impinging on a wedge in a two-dimensional supersonic flow field with a shock wave attached to the wedge. The closed-form solution yields analytical expressions for the equation of the droplet trajectory, the local rate of impingement and the impingement velocity at any point on the wedge surface, and the total rate of impingement. The analytical expressions are utilized to determine the impingement on the forward surfaces of diamond airfoils in supersonic flow fields with attached shock waves. The results presented include the following conditions: droplet diameters from 2 to 100 microns, pressure altitudes from sea level to 30,000 feet, free-stream static temperatures from 420 degrees to 460 degrees R. Also, free-stream Mach numbers from 1.1 to 2.0, semi-apex angles for the wedge from 1.14 degrees to 7.97 degrees, thickness-to-chord ratios for the diamond airfoil from 0.02 to 0.14, chord lengths from 1 to 20 feet, and angles of attack from zero to the inverse tangent of the airfoil thickness-to-chord ratio.

  13. Propulsion System Dynamic Modeling for the NASA Supersonic Concept Vehicle: AeroPropulsoServoElasticity

    Science.gov (United States)

    Kopasakis, George; Connolly, Joseph; Seidel, Jonathan

    2014-01-01

    A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural-aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report.propulsion system dynamics, the structural dynamics, and aerodynamics.

  14. Numerical Simulation of Reactive Flows in Overexpanded Supersonic Nozzle with Film Cooling

    Directory of Open Access Journals (Sweden)

    Mohamed Sellam

    2015-01-01

    Full Text Available Reignition phenomena occurring in a supersonic nozzle flow may present a crucial safety issue for rocket propulsion systems. These phenomena concern mainly rocket engines which use H2 gas (GH2 in the film cooling device, particularly when the nozzle operates under over expanded flow conditions at sea level or at low altitudes. Consequently, the induced wall thermal loads can lead to the nozzle geometry alteration, which in turn, leads to the appearance of strong side loads that may be detrimental to the rocket engine structural integrity. It is therefore necessary to understand both aerodynamic and chemical mechanisms that are at the origin of these processes. This paper is a numerical contribution which reports results from CFD analysis carried out for supersonic reactive flows in a planar nozzle cooled with GH2 film. Like the experimental observations, CFD simulations showed their ability to highlight these phenomena for the same nozzle flow conditions. Induced thermal load are also analyzed in terms of cooling efficiency and the results already give an idea on their magnitude. It was also shown that slightly increasing the film injection pressure can avoid the reignition phenomena by moving the separation shock towards the nozzle exit section.

  15. Aerodynamic damping in oscillatory pitching motion of canard-body combinations in unsteady supersonic regime

    International Nuclear Information System (INIS)

    Mateescu, D.

    1985-01-01

    A method of solution is developed in the present paper for studying the unsteady supersonic flow past a cruciform canard - conical body system, represented in the figure, which executes an oscillatory pitching motion of rotation. The generality of the analysis permits particular solutions such as the case of symmetrical cruciform canards (for l 1 =l 2 =l) used mainly in missile applications, and tail-body configurations (for l 2 =0 pr l 2 →∞ used in aeronautical applications, as well as more general solutions. Attached supersonic flow past the system, associated with small amplitude oscillations of reasonably low frequency with respect to a mean equilibrium position are assumed in this paper. As a result, the steady flow past the canard-body system at an attitude defined by the mean equilibrium position can be separated from the actual flow; general methods of solution for this steady flow have been established. The aim of the present analysis is to develop a method of solution for the unsteady motion resulting from the actual flow after the above separation, which incorporates the effects of the system oscillations. (author)

  16. Study of thermal and hydraulic efficiency of supersonic tube of temperature stratification

    Science.gov (United States)

    Tsynaeva, Anna A.; Nikitin, Maxim N.; Tsynaeva, Ekaterina A.

    2017-10-01

    Efficiency of supersonic pipe for temperature stratification with finned subsonic surface of heat transfer is the major of this paper. Thermal and hydraulic analyses of this pipe were conducted to asses effects from installation of longitudinal rectangular and parabolic fins as well as studs of cylindrical, rectangular and parabolic profiles. The analysis was performed based on refined empirical equations of similarity, dedicated to heat transfer of high-speed gas flow with plain wall, and Kármán equation with Nikuradze constants. Results revealed cylindrical studs (with height-to-diameter ratio of 5:1) to be 1.5 times more efficient than rectangular fins of the same height. At the same time rectangular fins (with height-to-thickness ratio of 5:1) were tend to enhance heat transfer rate up to 2.67 times compared to bare walls from subsonic side of the pipe. Longitudinal parabolic fins have minuscule effect on combined efficiency of considered pipe since extra head losses void any gain of heat transfer. Obtained results provide perspective of increasing efficiency of supersonic tube for temperature stratification. This significantly broadens device applicability in thermostatting systems for equipment, cooling systems for energy converting machinery, turbine blades and aerotechnics.

  17. Computational Investigation of Swirling Supersonic Jets Generated Through a Nozzle-Twisted Lance

    Science.gov (United States)

    Li, Mingming; Li, Qiang; Zou, Zongshu; An, Xizhong

    2017-02-01

    The dynamic characteristics of supersonic swirling jets generated through a nozzle-twisted lance are numerically studied. The essential features of the swirling jets are identified by defining a deviation angle. The effects of nozzle twist angle (NTA) on swirling flow intensity, coalescence characteristics, and dynamic parameter distributions of the jets are discussed. The rotational flow characteristics are revealed. The results show that the jets from the nozzle-twisted lance are imparted to a circumferential rotating movement around the lance axis, and such swirling flow is enhanced by increasing NTA. The enhanced swirling flow causes weaker coalescence of the jets, faster attenuations of the axial velocity, and higher heat transfer rate between the jets and surroundings. The supersonic core length, however, is found to be less sensitive to the swirling flow intensity. The radial spreading of the jets, changing non-monotonically with NTA, arrives at its maximum at 5 deg of NTA. Furthermore, the swirling flow induces a considerable tangential velocity component, and as a result, a holistic and effective horizontal swirling flow field develops. The y-vorticity distribution range and the corresponding magnitude turn larger with increasing NTA, which promote the vortex motion of the local fluid element and thus intensify the local mixing.

  18. Evaluation of water cooled supersonic temperature and pressure probes for application to 2000 F flows

    Science.gov (United States)

    Lagen, Nicholas T.; Seiner, John M.

    1990-01-01

    The development of water cooled supersonic probes used to study high temperature jet plumes is addressed. These probes are: total pressure, static pressure, and total temperature. The motivation for these experiments is the determination of high temperature supersonic jet mean flow properties. A 3.54 inch exit diameter water cooled nozzle was used in the tests. It is designed for exit Mach 2 at 2000 F exit total temperature. Tests were conducted using water cooled probes capable of operating in Mach 2 flow, up to 2000 F total temperature. Of the two designs tested, an annular cooling method was chosen as superior. Data at the jet exit planes, and along the jet centerline, were obtained for total temperatures of 900 F, 1500 F, and 2000 F, for each of the probes. The data obtained from the total and static pressure probes are consistent with prior low temperature results. However, the data obtained from the total temperature probe was affected by the water coolant. The total temperature probe was tested up to 2000 F with, and without, the cooling system turned on to better understand the heat transfer process at the thermocouple bead. The rate of heat transfer across the thermocouple bead was greater when the coolant was turned on than when the coolant was turned off. This accounted for the lower temperature measurement by the cooled probe. The velocity and Mach number at the exit plane and centerline locations were determined from the Rayleigh-Pitot tube formula.

  19. A new wall function boundary condition including heat release effect for supersonic combustion flows

    International Nuclear Information System (INIS)

    Gao, Zhen-Xun; Jiang, Chong-Wen; Lee, Chun-Hian

    2016-01-01

    Highlights: • A new wall function including heat release effect is theoretically derived. • The new wall function is a unified form holding for flows with/without combustion. • The new wall function shows good results for a supersonic combustion case. - Abstract: A new wall function boundary condition considering combustion heat release effect (denoted as CWFBC) is proposed, for efficient predictions of skin friction and heat transfer in supersonic combustion flows. Based on a standard flow model including boundary-layer combustion, the Shvab–Zeldovich coupling parameters are introduced to derive a new velocity law-of-the-wall including the influence of combustion. For the temperature law-of-the-wall, it is proposed to use the enthalpy–velocity relation, instead of the Crocco–Busemann equation, to eliminate explicit influence of chemical reactions. The obtained velocity and temperature law-of-the-walls constitute the CWFBC, which is a unified form simultaneously holding for single-species, multi-species mixing and multi-species reactive flows. The subsequent numerical simulations using this CWFBC on an experimental case indicate that the CWFBC could accurately reflect the influences on the skin friction and heat transfer by the chemical reactions and heat release, and show large improvements compared to previous WFBC. Moreover, the CWFBC can give accurate skin friction and heat flux for a coarse mesh with y"+ up to 200 for the experimental case, except for slightly larger discrepancy of the wall heat flux around ignition position.

  20. Design for LTE EOS and opacity experiments using supersonic radiation waves

    Science.gov (United States)

    Tierney, T. E.; Peterson, R. R.; Tierney, H. E.

    2007-11-01

    Opacity and EOS at 100-200 eV are important physical parameters in ICF experiments. We describe an experiment design that uses the supersonic propagation of hohlraum radiation in foams to isochorically heat samples. Laser and Z-pinch experiments frequently use 150 to 220-eV quasi-blackbody emission from hohlraums to drive physics experiments. A foam target encapsulated in a gold-wall cylinder is placed next to the hohlraum. The low density and opacity foam captures some hohlraum emission and generates a supersonically-propagating radiation wave. The material heated by the wave is cooler towards the high-albedo gold wall. Modeling and past measurements show that core regions of the foam have small thermal gradients. We place a small, thin sample (e.g., Al, Si, or Fe) in the thermally-uniform region. X-ray emission of tracers and the sample as well as quasi-continuum x-ray absorption will be measured using time-resolved x-ray spectroscopy. The foam's EOS can be measured to ±5% by blast waves with a well characterized drive. This experiment could use the OMEGA, Z-Beamlet, and/or ZR facilities to explore temperature-dependent conditions.

  1. A steady-state supersonic downflow in the transition region above a sunspot umbra

    Science.gov (United States)

    Straus, Thomas; Fleck, Bernhard; Andretta, Vincenzo

    2015-10-01

    We investigate a small-scale (~1.5 Mm along the slit), supersonic downflow of about 90 km s-1 in the transition region above the lightbridged sunspot umbra in AR 11836. The observations were obtained with the Interface Region Spectrograph (IRIS) on 2013 September 2 from 16:40 to 17:59 UT. The downflow shows up as redshifted "satellite" lines of the Si iv and O iv transition region lines and is remarkably steady over the observing period of nearly 80 min. The downflow is not visible in the chromospheric lines, which only show an intensity enhancement at the location of the downflow. The density inferred from the line ratio of the redshifted satellites of the O iv lines (Ne = 1010.6 ± 0.25 cm-3) is only a factor 2 smaller than the one inferred from the main components (Ne = 1010.95 ± 0.20 cm-3). Consequently, this implies a substantial mass flux (~5 × 10-7 g cm-2 s-1), which would evacuate the overlying corona on timescales close to 10 s. We interpret these findings as evidence of a stationary termination shock of a supersonic siphon flow in a cool loop that is rooted in the central umbra of the spot. The movie is available in electronic form at http://www.aanda.org

  2. IS MAGNETIC RECONNECTION THE CAUSE OF SUPERSONIC UPFLOWS IN GRANULAR CELLS?

    Energy Technology Data Exchange (ETDEWEB)

    Borrero, J. M.; Schmidt, W. [Kiepenheuer-Institut fuer Sonnenphysik, Schoeneckstr. 6, D-79110, Freiburg (Germany); Martinez Pillet, V.; Quintero Noda, C.; Bonet, J. A. [Instituto de Astrofisica de Canarias, Avd. Via Lactea s/n, E-38200 La Laguna (Spain); Del Toro Iniesta, J. C.; Bellot Rubio, L. R., E-mail: borrero@kis.uni-freiburg.de, E-mail: wolfgang@kis.uni-freiburg.de, E-mail: vmp@ll.iac.es, E-mail: cqn@ll.iac.es, E-mail: jab@ll.iac.es, E-mail: jti@iaa.es, E-mail: lbellot@iaa.es [Instituto de Astrofisica de Andalucia (CSIC), Apdo. de Correos 3004, E-18080 Granada (Spain)

    2013-05-01

    In a previous work, we reported on the discovery of supersonic magnetic upflows on granular cells in data from the SUNRISE/IMaX instrument. In the present work, we investigate the physical origin of these events employing data from the same instrument but with higher spectral sampling. By means of the inversion of Stokes profiles we are able to recover the physical parameters (temperature, magnetic field, line-of-sight velocity, etc.) present in the solar photosphere at the time of these events. The inversion is performed in a Monte-Carlo-like fashion, that is, repeating it many times with different initializations and retaining only the best result. We find that many of the events are characterized by a reversal in the polarity of the magnetic field along the vertical direction in the photosphere, accompanied by an enhancement in the temperature and by supersonic line-of-sight velocities. In about half of the studied events, large blueshifted and redshifted line-of-sight velocities coexist above/below each other. These features can be explained in terms of magnetic reconnection, where the energy stored in the magnetic field is released in the form of kinetic and thermal energy when magnetic field lines of opposite polarities coalesce. However, the agreement with magnetic reconnection is not perfect and, therefore, other possible physical mechanisms might also play a role.

  3. Laser driven supersonic flow over a compressible foam surface on the Nike lasera)

    Science.gov (United States)

    Harding, E. C.; Drake, R. P.; Aglitskiy, Y.; Plewa, T.; Velikovich, A. L.; Gillespie, R. S.; Weaver, J. L.; Visco, A.; Grosskopf, M. J.; Ditmar, J. R.

    2010-05-01

    A laser driven millimeter-scale target was used to generate a supersonic shear layer in an attempt to create a Kelvin-Helmholtz (KH) unstable interface in a high-energy-density (HED) plasma. The KH instability is a fundamental fluid instability that remains unexplored in HED plasmas, which are relevant to the inertial confinement fusion and astrophysical environments. In the experiment presented here the Nike laser [S. P. Obenschain et al., Phys. Plasmas 3, 2098 (1996)] was used to create and drive Al plasma over a rippled foam surface. In response to the supersonic Al flow (Mach=2.6±1.1) shocks should form in the Al flow near the perturbations. The experimental data were used to infer the existence and location of these shocks. In addition, the interface perturbations show growth that has possible contributions from both KH and Richtmyer-Meshkov instabilities. Since compressible shear layers exhibit smaller growth, it is important to use the KH growth rate derived from the compressible dispersion relation.

  4. Laser driven supersonic flow over a compressible foam surface on the Nike laser

    International Nuclear Information System (INIS)

    Harding, E. C.; Drake, R. P.; Gillespie, R. S.; Visco, A.; Grosskopf, M. J.; Ditmar, J. R.; Aglitskiy, Y.; Velikovich, A. L.; Weaver, J. L.; Plewa, T.

    2010-01-01

    A laser driven millimeter-scale target was used to generate a supersonic shear layer in an attempt to create a Kelvin-Helmholtz (KH) unstable interface in a high-energy-density (HED) plasma. The KH instability is a fundamental fluid instability that remains unexplored in HED plasmas, which are relevant to the inertial confinement fusion and astrophysical environments. In the experiment presented here the Nike laser [S. P. Obenschain et al., Phys. Plasmas 3, 2098 (1996)] was used to create and drive Al plasma over a rippled foam surface. In response to the supersonic Al flow (Mach=2.6±1.1) shocks should form in the Al flow near the perturbations. The experimental data were used to infer the existence and location of these shocks. In addition, the interface perturbations show growth that has possible contributions from both KH and Richtmyer-Meshkov instabilities. Since compressible shear layers exhibit smaller growth, it is important to use the KH growth rate derived from the compressible dispersion relation.

  5. Effects of variable specific heat on energy transfer in a high-temperature supersonic channel flow

    Science.gov (United States)

    Chen, Xiaoping; Li, Xiaopeng; Dou, Hua-Shu; Zhu, Zuchao

    2018-05-01

    An energy transfer mechanism in high-temperature supersonic turbulent flow for variable specific heat (VSH) condition through turbulent kinetic energy (TKE), mean kinetic energy (MKE), turbulent internal energy (TIE) and mean internal energy (MIE) is proposed. The similarities of energy budgets between VSH and constant specific heat (CSH) conditions are investigated by introducing a vibrational energy excited degree and considering the effects of fluctuating specific heat. Direct numerical simulation (DNS) of temporally evolving high-temperature supersonic turbulent channel flow is conducted at Mach number 3.0 and Reynolds number 4800 combined with a constant dimensional wall temperature 1192.60 K for VSH and CSH conditions to validate the proposed energy transfer mechanism. The differences between the terms in the two kinetic energy budgets for VSH and CSH conditions are small; however, the magnitude of molecular diffusion term for VSH condition is significantly smaller than that for CSH condition. The non-negligible energy transfer is obtained after neglecting several small terms of diffusion, dissipation and compressibility related. The non-negligible energy transfer involving TIE includes three processes, in which energy can be gained from TKE and MIE and lost to MIE. The same non-negligible energy transfer through TKE, MKE and MIE is observed for both the conditions.

  6. Numerical analysis on flows in supersonic air intakes. Choonsoku kuki toriireguchi no nagare no suchi kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, T.; Tamura, N.; Sekino, N.; Tsujimura, N. (Nissan Motor Co. Ltd., Tokyo (Japan))

    1992-06-25

    By applying computational fluid dynamics (CFD) to a flow in the supersonic air intake of rocket, appropriateness of computational result was confirmed from a comparison with the wind tunnel test result. In order for the air intake type rocket to heighten the combustion efficiency of fuel and air, it is important to possibly minimize the total pressure loss of air which has been taken in and maintain the air flow rate. A numerical analysis was made through modeling the sectional shape of wind tunnel test body and analyzing the two-dimensional flow by Reynolds-averaged Navier-Stokes equations. The computational result of analysis coincided well with the pressure measurement result in wind tunnel test. Having elucidated the main factors of total pressure loss in a two-dimensionally curved flow passage, the CFD computation gave a possibility that the total pressure loss is considerably low against that passage if improved in shape. If simultaneously used with a characteristic curve method, the CFD computation made it possible to optimize the pressure recovery characteristics in the axially symmetric air intake. The CFD can be expected to be an effective method of designing the basic shape of supersonic air intake. 9 refs., 14 figs.

  7. Linearised dynamics and non-modal instability analysis of an impinging under-expanded supersonic jet

    Science.gov (United States)

    Karami, Shahram; Stegeman, Paul C.; Theofilis, Vassilis; Schmid, Peter J.; Soria, Julio

    2018-04-01

    Non-modal instability analysis of the shear layer near the nozzle of a supersonic under-expanded impinging jet is studied. The shear layer instability is considered to be one of the main components of the feedback loop in supersonic jets. The feedback loop is observed in instantaneous visualisations of the density field where it is noted that acoustic waves scattered by the nozzle lip internalise as shear layer instabilities. A modal analysis describes the asymptotic limit of the instability disturbances and fails to capture short-time responses. Therefore, a non-modal analysis which allows the quantitative description of the short-time amplification or decay of a disturbance is performed by means of a local far-field pressure pulse. An impulse response analysis is performed which allows a wide range of frequencies to be excited. The temporal and spatial growths of the disturbances in the shear layer near the nozzle are studied by decomposing the response using dynamic mode decomposition and Hilbert transform analysis. The short-time response shows that disturbances with non-dimensionalised temporal frequencies in the range of 1 to 4 have positive growth rates in the shear layer. The Hilbert transform analysis shows that high non-dimensionalised temporal frequencies (>4) are dampened immediately, whereas low non-dimensionalised temporal frequencies (analysis show that spatial frequencies between 1 and 3 have positive spatial growth rates. Finally, the envelope of the streamwise velocity disturbances reveals the presence of a convective instability.

  8. Particle fuelling for long pulse with standard gas puff and supersonic pulsed gas injection

    International Nuclear Information System (INIS)

    Bucalossi, J.; Tsitrone, E.; Martin, G.

    2003-01-01

    In addition to the standard gas puff and to the technically complex pellet injection, a novel intermediate method, based on the injection of a supersonic high density cloud of neutrals, has been recently implemented on the Tore Supra tokamak. Fuelling efficiency, in the 30-50% range are found while it lies in the 10-20% range for the gas puff. It is not sensitive to the plasma density and to the additional heating. According to modelling, the increased efficiency is attributed to the very short injection duration compared to the particle confinement time and to the strong cooling of the plasma edge resulting from the massive injection of matter. A feedback loop on the frequency of the injector has been successfully implemented to control the plasma density. In long pulse experiments (>200s), wall saturation has not been reached. Gas puffing rate was typically around 1 Pa.m 3 s -1 while dynamic wall retention around 0.6 Pa.m 3 s -1 . Co-deposited carbon layer could trap such large amounts of gas. A discharge fuelled by supersonic pulsed gas injections exhibits lower wall retention than a gas puff fuelled discharge. (author)

  9. A multivariate quadrature based moment method for LES based modeling of supersonic combustion

    Science.gov (United States)

    Donde, Pratik; Koo, Heeseok; Raman, Venkat

    2012-07-01

    The transported probability density function (PDF) approach is a powerful technique for large eddy simulation (LES) based modeling of scramjet combustors. In this approach, a high-dimensional transport equation for the joint composition-enthalpy PDF needs to be solved. Quadrature based approaches provide deterministic Eulerian methods for solving the joint-PDF transport equation. In this work, it is first demonstrated that the numerical errors associated with LES require special care in the development of PDF solution algorithms. The direct quadrature method of moments (DQMOM) is one quadrature-based approach developed for supersonic combustion modeling. This approach is shown to generate inconsistent evolution of the scalar moments. Further, gradient-based source terms that appear in the DQMOM transport equations are severely underpredicted in LES leading to artificial mixing of fuel and oxidizer. To overcome these numerical issues, a semi-discrete quadrature method of moments (SeQMOM) is formulated. The performance of the new technique is compared with the DQMOM approach in canonical flow configurations as well as a three-dimensional supersonic cavity stabilized flame configuration. The SeQMOM approach is shown to predict subfilter statistics accurately compared to the DQMOM approach.

  10. Analysis of impact of general-purpose graphics processor units in supersonic flow modeling

    Science.gov (United States)

    Emelyanov, V. N.; Karpenko, A. G.; Kozelkov, A. S.; Teterina, I. V.; Volkov, K. N.; Yalozo, A. V.

    2017-06-01

    Computational methods are widely used in prediction of complex flowfields associated with off-normal situations in aerospace engineering. Modern graphics processing units (GPU) provide architectures and new programming models that enable to harness their large processing power and to design computational fluid dynamics (CFD) simulations at both high performance and low cost. Possibilities of the use of GPUs for the simulation of external and internal flows on unstructured meshes are discussed. The finite volume method is applied to solve three-dimensional unsteady compressible Euler and Navier-Stokes equations on unstructured meshes with high resolution numerical schemes. CUDA technology is used for programming implementation of parallel computational algorithms. Solutions of some benchmark test cases on GPUs are reported, and the results computed are compared with experimental and computational data. Approaches to optimization of the CFD code related to the use of different types of memory are considered. Speedup of solution on GPUs with respect to the solution on central processor unit (CPU) is compared. Performance measurements show that numerical schemes developed achieve 20-50 speedup on GPU hardware compared to CPU reference implementation. The results obtained provide promising perspective for designing a GPU-based software framework for applications in CFD.

  11. Heterogeneous Calculation of {epsilon}

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Alf

    1961-02-15

    A heterogeneous method of calculating the fast fission factor given by Naudet has been applied to the Carlvik - Pershagen definition of {epsilon}. An exact calculation of the collision probabilities is included in the programme developed for the Ferranti - Mercury computer.

  12. Heterogeneous Calculation of ε

    International Nuclear Information System (INIS)

    Jonsson, Alf

    1961-02-01

    A heterogeneous method of calculating the fast fission factor given by Naudet has been applied to the Carlvik - Pershagen definition of ε. An exact calculation of the collision probabilities is included in the programme developed for the Ferranti - Mercury computer

  13. Three dimensional model calculations of the global dispersion of high speed aircraft exhaust and implications for stratospheric ozone loss

    Science.gov (United States)

    Douglass, Anne R.; Rood, Richard B.; Jackman, Charles H.; Weaver, Clark J.

    1994-01-01

    Two-dimensional (zonally averaged) photochemical models are commonly used for calculations of ozone changes due to various perturbations. These include calculating the ozone change expected as a result of change in the lower stratospheric composition due to the exhaust of a fleet of supersonic aircraft flying in the lower stratosphere. However, zonal asymmetries are anticipated to be important to this sort of calculation. The aircraft are expected to be restricted from flying over land at supersonic speed due to sonic booms, thus the pollutant source will not be zonally symmetric. There is loss of pollutant through stratosphere/troposphere exchange, but these processes are spatially and temporally inhomogeneous. Asymmetry in the pollutant distribution contributes to the uncertainty in the ozone changes calculated with two dimensional models. Pollutant distributions for integrations of at least 1 year of continuous pollutant emissions along flight corridors are calculated using a three dimensional chemistry and transport model. These distributions indicate the importance of asymmetry in the pollutant distributions to evaluation of the impact of stratospheric aircraft on ozone. The implications of such pollutant asymmetries to assessment calculations are discussed, considering both homogeneous and heterogeneous reactions.

  14. Numerical Analysis on the Compressible Flow Characteristics of Supersonic Jet Caused by High-Pressure Pipe Rupture Using CFD

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jong-Kil; Yoon, Jun-Kyu [Gachon Univ., Sungnam (Korea, Republic of); Kim, Kwang-Chu [KEPCO-E& C, Kimchun (Korea, Republic of)

    2017-10-15

    A rupture in a high-pressure pipe causes the fluid in the pipe to be discharged in the atmosphere at a high speed resulting in a supersonic jet that generates the compressible flow. This supersonic jet may display complicated and unsteady behavior in general . In this study, Computational Fluid Dynamics (CFD) analysis was performed to investigate the compressible flow generated by a supersonic jet ejected from a high-pressure pipe. A Shear Stress Transport (SST) turbulence model was selected to analyze the unsteady nature of the flow, which depends upon the various gases as well as the diameter of the pipe. In the CFD analysis, the basic boundary conditions were assumed to be as follows: pipe of diameter 10 cm, jet pressure ratio of 5, and an inlet gas temperature of 300 K. During the analysis, the behavior of the shockwave generated by a supersonic jet was observed and it was found that the blast wave was generated indirectly. The pressure wave characteristics of hydrogen gas, which possesses the smallest molecular mass, showed the shortest distance to the safety zone. There were no significant difference observed for nitrogen gas, air, and oxygen gas, which have similar molecular mass. In addition, an increase in the diameter of the pipe resulted in the ejected impact caused by the increased flow rate to become larger and the zone of jet influence to extend further.

  15. Schlieren study of a sonic jet injected into a supersonic cross flow using high-current pulsed LEDs

    NARCIS (Netherlands)

    Giskes, Ella; Verschoof, Ruben A.; Segerink, Frans B.; Venner, Cornelis H.

    2017-01-01

    Benefiting from the development of increasingly advanced high speed cameras, flow visualization and analysis nowadays yield detailed data of the flow field in many applications. Notwithstanding this progress, for high speed and supersonic flows it is still not trivial to capture high quality images.

  16. Preparation of ultra-fine calcium carbonate by a solvent-free reaction using supersonic airflow and low temperatures

    OpenAIRE

    Cai, Yan-Hua; Ma, Dong-Mei; Peng, Ru-Fang; Chu, Shi-Jin

    2008-01-01

    The treatment of calcium chloride with sodium carbonate under solvent-free conditions with a supersonic airflow and at a low heating temperature leads to the synthesis of ultra-fine calcium carbonate. The reaction not only involves mild conditions, a simple operation, and high yields but also gives a high conversion rate.

  17. A parametric study on supersonic/hypersonic flutter behavior of aero-thermo-elastic geometrically imperfect curved skin panel

    NARCIS (Netherlands)

    Abbas, L.K.; Rui, X.; Marzocca, P.; Abdalla, M.; De Breuker, R.

    2011-01-01

    In this paper, the effect of the system parameters on the flutter of a curved skin panel forced by a supersonic/hypersonic unsteady flow is numerically investigated. The aeroelastic model investigated includes the third-order piston theory aerodynamics for modeling the flow-induced forces and the

  18. High-Resolution Spectroscopy of He{_2}^+ Using Rydberg-Series Extrapolation and Zeeman-Decelerated Supersonic Beams of Metastable He_2

    Science.gov (United States)

    Jansen, Paul; Semeria, Luca; Merkt, Frederic

    2016-06-01

    Having only three electrons, He{_2}^+ represents a system for which highly accurate ab initio calculations are possible. The latest calculations of rovibrational energies in He{_2}^+ do not include relativistic or QED corrections but claim an accuracy of 120 MHz We have performed high-resolution Rydberg spectroscopy of metastable He_2 molecules and employed multichannel-quantum-defect-theory extrapolation techniques to determine the rotational energy-level structure in the He{_2}^+ ion. To this end, we have produced samples of metastable helium molecules in supersonic beams with velocities tunable down to 100 m/s by combining a cryogenic supersonic-beam source with a multistage Zeeman decelerator. The metastable He_2 molecules are excited to np Rydberg states using the frequency-doubled output of a pulse-amplified ring dye laser. Although the bandwidth of the laser system is too large to observe the reduction of the Doppler width resulting from deceleration, the deceleration greatly simplifies the spectral assignments because of its spin-rotational state selectivity. Our approach enabled us to determine the rotational structure of He_2 with an unprecedented accuracy of 18 MHz, to quantify the size of the relativistic and QED corrections by comparison with the results of Tung et al. and to precisely measure the rotational structure of the metastable state for comparison with the results of Focsa et al. Here, we present an extension of these measurements in which we have measured higher rotational intervals of He{_2}^+. In addition, we have replaced the pulsed UV laser by a cw UV laser and improved the resolution of the spectra by a factor of more than five. W.-C. Tung, M. Pavanello and L. Adamowicz, J. Chem. Phys. 136, 104309 (2012). P. Jansen, L. Semeria, L. Esteban Hofer, S. Scheidegger, J.A. Agner, H. Schmutz, and F. Merkt, Phys. Rev. Lett. 115, 133202 (2015). D. Sprecher, J. Liu, T. Krähenmann, M. Schäfer, and F. Merkt, J. Chem. Phys. 140, 064304 (2014). M

  19. Core calculations of JMTR

    Energy Technology Data Exchange (ETDEWEB)

    Nagao, Yoshiharu [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    1998-03-01

    In material testing reactors like the JMTR (Japan Material Testing Reactor) of 50 MW in Japan Atomic Energy Research Institute, the neutron flux and neutron energy spectra of irradiated samples show complex distributions. It is necessary to assess the neutron flux and neutron energy spectra of an irradiation field by carrying out the nuclear calculation of the core for every operation cycle. In order to advance core calculation, in the JMTR, the application of MCNP to the assessment of core reactivity and neutron flux and spectra has been investigated. In this study, in order to reduce the time for calculation and variance, the comparison of the results of the calculations by the use of K code and fixed source and the use of Weight Window were investigated. As to the calculation method, the modeling of the total JMTR core, the conditions for calculation and the adopted variance reduction technique are explained. The results of calculation are shown. Significant difference was not observed in the results of neutron flux calculations according to the difference of the modeling of fuel region in the calculations by K code and fixed source. The method of assessing the results of neutron flux calculation is described. (K.I.)

  20. Supersonic transient magnetic resonance elastography for quantitative assessment of tissue elasticity.

    Science.gov (United States)

    Liu, Yu; Liu, Jingfei; Fite, Brett Z; Foiret, Josquin; Ilovitsh, Asaf; Leach, J Kent; Dumont, Erik; Caskey, Charles F; Ferrara, Katherine W

    2017-05-21

    Non-invasive, quantitative methods to assess the properties of biological tissues are needed for many therapeutic and tissue engineering applications. Magnetic resonance elastography (MRE) has historically relied on external vibration to generate periodic shear waves. In order to focally assess a biomaterial or to monitor the response to ablative therapy, the interrogation of a specific region of interest by a focused beam is desirable and transient MRE (t-MRE) techniques have previously been developed to accomplish this goal. Also, strategies employing a series of discrete ultrasound pulses directed to increasing depths along a single line-of-sight have been designed to generate a quasi-planar shear wave. Such 'supersonic' excitations have been applied for ultrasound elasticity measurements. The resulting shear wave is higher in amplitude than that generated from a single excitation and the properties of the media are simply visualized and quantified due to the quasi-planar wave geometry and the opportunity to generate the wave at the site of interest. Here for the first time, we extend the application of supersonic methods by developing a protocol for supersonic transient magnetic resonance elastography (sst-MRE) using an MR-guided focused ultrasound system capable of therapeutic ablation. We apply the new protocol to quantify tissue elasticity in vitro using biologically-relevant inclusions and tissue-mimicking phantoms, compare the results with elasticity maps acquired with ultrasound shear wave elasticity imaging (US-SWEI), and validate both methods with mechanical testing. We found that a modified time-of-flight (TOF) method efficiently quantified shear modulus from sst-MRE data, and both the TOF and local inversion methods result in similar maps based on US-SWEI. With a three-pulse excitation, the proposed sst-MRE protocol was capable of visualizing quasi-planar shear waves propagating away from the excitation location and detecting differences in shear

  1. Supersonic micro-jets and their application to few-cycle laser-driven electron acceleration

    International Nuclear Information System (INIS)

    Schmid, Karl

    2009-01-01

    This thesis covers the few-cycle laser-driven acceleration of electrons in a laser-generated plasma. The laser system employed in this work is a new development based on optical parametric chirped pulse amplification and is the only multi-TW few-cycle laser in the world. In the experiment, the laser beam is focused onto a supersonic helium gas jet which leads to the formation of a plasma channel. The laser pulse, having an intensity of 10 19 W/cm 2 propagates through the plasma with an electron density of 2 x 10 19 cm -3 and forms via a highly nonlinear interaction a strongly anharmonic plasma wave. The amplitude of the wave is so large that the wave breaks, thereby injecting electrons from the background plasma into the accelerating phase. The energy transfer from the laser pulse to the plasma is so strong that the maximum propagation distance is limited to the 100 m range. Therefore, gas jets specifically tuned to these requirements have to be employed. The properties of microscopic supersonic gas jets are thoroughly analyzed in this work. Based on numeric flow simulation, this study encompasses several extensive parameter studies that illuminate all relevant features of supersonic flows in microscopic gas nozzles. This allowed the optimized design of de Laval nozzles with exit diameters ranging from 150 μm to 3 mm. The employment of these nozzles in the experiment greatly improved the electron beam quality. After these optimizations, the laser-driven electron accelerator now yields monoenergetic electron pulses with energies up to 50 MeV and charges between one and ten pC. The electron beam has a typical divergence of 5 mrad and comprises an energy spectrum that is virtually free from low energetic background. The electron pulse duration could not yet be determined experimentally but simulations point towards values in the range of 1 fs. The acceleration gradient is estimated from simulation and experiment to be approximately 0.5 TV/m. The electron accelerator

  2. High-speed and supersonic upward plasma drifts: multi-instrumental study

    Science.gov (United States)

    Astafyeva, E.; Zakharenkova, I.; Hairston, M. R.; Huba, J.; Coley, W. R.

    2017-12-01

    Since the pioneering observations by Aggson et al. (1992, JGR, doi: 10.1002/92JA00644), there have been several reports of the occurrence of high-speed (Vz>800 m/s) and supersonic plasma flows in the post-sunset (e.g., Hysell et al., 1994, JGR, doi: 10.1029/94JA00476; Hanson et al., 1997, JGR, doi: 10.1029/96JA03376) and the pre-dawn sector (Astafyeva and Zakharenkova, 2015, GRL, doi:10.1002/2015GL066369). However, despite this observational evidence, these events remain rare and are not well understood. The main issue is to determine the background conditions leading to the occurrence of these high-speed plasma drifts. In this work, we perform a multi-instrumental study of high-speed and supersonic upward plasma drift events/structures. For this purpose, we analyze data from several ground-based and space-borne instruments, including data from the DMSP, Swarm and C/NOFS (IVM instrument) satellites. In addition to the space-borne instruments, we use data from ground-based GPS-receivers and ionosondes to further investigate the background ionosphere conditions, as well as the effects produced by the plasma bubbles and ionospheric irregularities. Besides the observations, we add the SAMI3/ESF modeling results on plasma bubble simulations and high-speed drifts inside plasma bubbles. TIE-GCM runs (from the CCMC, https://ccmc.gsfc.nasa.gov) are used to define the background atmospheric/ionospheric and electrodynamical conditions leading to the occurrence of the high-speed and supersonic plasma drift events. Our search of events with upward plasma drift exceeding 800 m/s in the data of DMSP for the years 2002-2016 shows that such high-speed events are extremely rare. During this period of time, only 6 events were found, two of them occurred during the recovery phase of a geomagnetic storm, while the other four were detected during geomagnetically quiet conditions. Concerning the generation of such events, our preliminary results show that enhanced electric fields are

  3. Supersonic micro-jets and their application to few-cycle laser-driven electron acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Schmid, Karl

    2009-07-23

    This thesis covers the few-cycle laser-driven acceleration of electrons in a laser-generated plasma. The laser system employed in this work is a new development based on optical parametric chirped pulse amplification and is the only multi-TW few-cycle laser in the world. In the experiment, the laser beam is focused onto a supersonic helium gas jet which leads to the formation of a plasma channel. The laser pulse, having an intensity of 10{sup 19} W/cm{sup 2} propagates through the plasma with an electron density of 2 x 10{sup 19} cm{sup -3} and forms via a highly nonlinear interaction a strongly anharmonic plasma wave. The amplitude of the wave is so large that the wave breaks, thereby injecting electrons from the background plasma into the accelerating phase. The energy transfer from the laser pulse to the plasma is so strong that the maximum propagation distance is limited to the 100 m range. Therefore, gas jets specifically tuned to these requirements have to be employed. The properties of microscopic supersonic gas jets are thoroughly analyzed in this work. Based on numeric flow simulation, this study encompasses several extensive parameter studies that illuminate all relevant features of supersonic flows in microscopic gas nozzles. This allowed the optimized design of de Laval nozzles with exit diameters ranging from 150 {mu}m to 3 mm. The employment of these nozzles in the experiment greatly improved the electron beam quality. After these optimizations, the laser-driven electron accelerator now yields monoenergetic electron pulses with energies up to 50 MeV and charges between one and ten pC. The electron beam has a typical divergence of 5 mrad and comprises an energy spectrum that is virtually free from low energetic background. The electron pulse duration could not yet be determined experimentally but simulations point towards values in the range of 1 fs. The acceleration gradient is estimated from simulation and experiment to be approximately 0.5 TV/m. The

  4. Supersonic Jump

    Science.gov (United States)

    Muller, Andreas

    2013-01-01

    On October 14,2012, Felix Baumgartner, an Austrian sky-diver, set some new world records for his discipline. Jumping from a height of about 39 km, he reached a top speed of 1342 km/h, becoming the first human being to break the sound barrier in free fall. In order to understand some essential physics aspects of this remarkable feat, we wonder why…

  5. Electronics Environmental Benefits Calculator

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Electronics Environmental Benefits Calculator (EEBC) was developed to assist organizations in estimating the environmental benefits of greening their purchase,...

  6. Electrical installation calculations basic

    CERN Document Server

    Kitcher, Christopher

    2013-01-01

    All the essential calculations required for basic electrical installation workThe Electrical Installation Calculations series has proved an invaluable reference for over forty years, for both apprentices and professional electrical installation engineers alike. The book provides a step-by-step guide to the successful application of electrical installation calculations required in day-to-day electrical engineering practice. A step-by-step guide to everyday calculations used on the job An essential aid to the City & Guilds certificates at Levels 2 and 3Fo

  7. Electrical installation calculations advanced

    CERN Document Server

    Kitcher, Christopher

    2013-01-01

    All the essential calculations required for advanced electrical installation workThe Electrical Installation Calculations series has proved an invaluable reference for over forty years, for both apprentices and professional electrical installation engineers alike. The book provides a step-by-step guide to the successful application of electrical installation calculations required in day-to-day electrical engineering practiceA step-by-step guide to everyday calculations used on the job An essential aid to the City & Guilds certificates at Levels 2 and 3For apprentices and electrical installatio

  8. Radar Signature Calculation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: The calculation, analysis, and visualization of the spatially extended radar signatures of complex objects such as ships in a sea multipath environment and...

  9. Waste Package Lifting Calculation

    International Nuclear Information System (INIS)

    H. Marr

    2000-01-01

    The objective of this calculation is to evaluate the structural response of the waste package during the horizontal and vertical lifting operations in order to support the waste package lifting feature design. The scope of this calculation includes the evaluation of the 21 PWR UCF (pressurized water reactor uncanistered fuel) waste package, naval waste package, 5 DHLW/DOE SNF (defense high-level waste/Department of Energy spent nuclear fuel)--short waste package, and 44 BWR (boiling water reactor) UCF waste package. Procedure AP-3.12Q, Revision 0, ICN 0, calculations, is used to develop and document this calculation

  10. Applications of Laplace transform methods to airfoil motion and stability calculations

    Science.gov (United States)

    Edwards, J. W.

    1979-01-01

    This paper reviews the development of generalized unsteady aerodynamic theory and presents a derivation of the generalized Possio integral equation. Numerical calculations resolve questions concerning subsonic indicial lift functions and demonstrate the generation of Kutta waves at high values of reduced frequency, subsonic Mach number, or both. The use of rational function approximations of unsteady aerodynamic loads in aeroelastic stability calculations is reviewed, and a reformulation of the matrix Pade approximation technique is given. Numerical examples of flutter boundary calculations for a wing which is to be flight tested are given. Finally, a simplified aerodynamic model of transonic flow is used to study the stability of an airfoil exposed to supersonic and subsonic flow regions.

  11. Supplement 1: Advanced nuclear turbojet powerplant characteristics summary for supersonic aircraft

    International Nuclear Information System (INIS)

    Larson, John W.

    1959-01-01

    The powerplant characteristics previously described in PWAC-275 were based on the use of low compressor pressure ratio nuclear turbojet engines equipped with interburners but without afterburners. The performance of an afterburning version of the same engine is presented in Section B of this supplement. The engine selection for the previous report and for Section B of this supplement was based on best engine performance at Mach No. 3 on nuclear heat alone. For this reason a low compression turbojet engine was selected. However, it is desirable that the nuclear data in report PWAC-275 be useful for both subsonic and supersonic missions. Therefore, the engine performance has been computed for a nuclear conversion of the Pratt & Whitney Aircraft J-58 turbojet engine which has a higher compressor pressure ratio. The performance of this engine is outlined in Section C of this supplement.

  12. Supersonic Combustion in Air-Breathing Propulsion Systems for Hypersonic Flight

    Science.gov (United States)

    Urzay, Javier

    2018-01-01

    Great efforts have been dedicated during the last decades to the research and development of hypersonic aircrafts that can fly at several times the speed of sound. These aerospace vehicles have revolutionary applications in national security as advanced hypersonic weapons, in space exploration as reusable stages for access to low Earth orbit, and in commercial aviation as fast long-range methods for air transportation of passengers around the globe. This review addresses the topic of supersonic combustion, which represents the central physical process that enables scramjet hypersonic propulsion systems to accelerate aircrafts to ultra-high speeds. The description focuses on recent experimental flights and ground-based research programs and highlights associated fundamental flow physics, subgrid-scale model development, and full-system numerical simulations.

  13. Supersonic Fe beam source for chromatic aberration-free laser focusing of atoms

    CERN Document Server

    Bosch, R C M; Van der Straten, P; Leeuwen, K A H

    2002-01-01

    A monochromatic Fe beam is generated by heated supersonic expansion of argon seeded with Fe vapor. At a nozzle temperature of 1930 K and 800 torr argon inlet pressure the Fe beam has an axial velocity spread of 8% and intensity of 3 x 10 sup 1 sup 5 s sup - sup 1 sr sup - sup 1 , corresponding to a deposition rate of 10 nm/h at 150 mm from the nozzle. The two-chamber alumina crucibles are chemically stable for liquid Fe. With 400 mm sup 3 Fe we have operated for more than 200 hours without reloading. The power consumption at 1930 K is 750 W. Temperature stability at constant power (without feedback) is better than 30 K. The source is intended for deposition of nano-structures by laser focusing of the Fe beam. The small axial velocity spread virtually eliminates the increase in focal spot size due to chromatic aberration. (authors)

  14. Supersonic Heat Wave Propagation in Laser-Produced Underdense Plasma for Efficient X-Ray Generation

    International Nuclear Information System (INIS)

    Tanabe, M.; Nishimura, H.; Fujioka, S.; Nagai, K.; Iwamae, A.; Ohnishi, N.; Fournier, K.B.; Girard, F.; Primout, M.; Villette, B.; Tobin, M.; Mima, K.

    2008-01-01

    We have observed supersonic heat wave propagation in a low-density aerogel target (ρ ∼ 3.2 mg/cc) irradiated at the intensity of 4 x 10 14 W/cm 2 . The heat wave propagation was measured with a time-resolved x-ray imaging diagnostics, and the results were compared with simulations made with the two-dimensional radiation-hydrodynamic code, RAICHO. Propagation velocity of the ionization front gradually decreased as the wave propagates into the target. The reason of decrease is due to increase of laser absorption region as the front propagates and interplay of hydrodynamic motion and reflection of laser propagation. These features are well reported with the simulation

  15. Development of a Supersonic Atomic Oxygen Nozzle Beam Source for Crossed Beam Scattering Experiments

    Science.gov (United States)

    Sibener, S. J.; Buss, R. J.; Lee, Y. T.

    1978-05-01

    A high pressure, supersonic, radio frequency discharge nozzle beam source was developed for the production of intense beams of ground state oxygen atoms. An efficient impedance matching scheme was devised for coupling the radio frequency power to the plasma as a function of both gas pressure and composition. Techniques for localizing the discharge directly behind the orifice of a water-cooled quartz nozzle were also developed. The above combine to yield an atomic oxygen beam source which produces high molecular dissociation in oxygen seeded rare gas mixtures at total pressures up to 200 torr: 80 to 90% dissociation for oxygen/argon mixtures and 60 to 70% for oxygen/helium mixtures. Atomic oxygen intensities are found to be greater than 10{sup 17} atom sr{sup -1} sec{sup -1}. A brief discussion of the reaction dynamics of 0 + IC1 ..-->.. I0 + C1 is also presented.

  16. Nanomanufacturing of titania interfaces with controlled structural and functional properties by supersonic cluster beam deposition

    Energy Technology Data Exchange (ETDEWEB)

    Podestà, Alessandro, E-mail: alessandro.podesta@mi.infn.it, E-mail: pmilani@mi.infn.it; Borghi, Francesca; Indrieri, Marco; Bovio, Simone; Piazzoni, Claudio; Milani, Paolo, E-mail: alessandro.podesta@mi.infn.it, E-mail: pmilani@mi.infn.it [Centro Interdisciplinare Materiali e Interfacce Nanostrutturati (C.I.Ma.I.Na.), Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy)

    2015-12-21

    Great emphasis is placed on the development of integrated approaches for the synthesis and the characterization of ad hoc nanostructured platforms, to be used as templates with controlled morphology and chemical properties for the investigation of specific phenomena of great relevance in interdisciplinary fields such as biotechnology, medicine, and advanced materials. Here, we discuss the crucial role and the advantages of thin film deposition strategies based on cluster-assembling from supersonic cluster beams. We select cluster-assembled nanostructured titania (ns-TiO{sub 2}) as a case study to demonstrate that accurate control over morphological parameters can be routinely achieved, and consequently, over several relevant interfacial properties and phenomena, like surface charging in a liquid electrolyte, and proteins and nanoparticles adsorption. In particular, we show that the very good control of nanoscale morphology is obtained by taking advantage of simple scaling laws governing the ballistic deposition regime of low-energy, mass-dispersed clusters with reduced surface mobility.

  17. Gauge field theoretic solution of a uniformly moving screw dislocation and admissibility of supersonic speeds

    International Nuclear Information System (INIS)

    Sharma, P.; Zhang, X.

    2006-01-01

    The failure of classical elasticity to address dislocation behavior spatially close to its core and (in Lorentz-type fashion) near the speed of sound is well known. In gauge field theory of defects, the latter are not postulated a priori in an ad hoc fashion rather defects such as dislocations arise naturally as a consequence of broken translational symmetry exhibiting solutions that are physically meaningful (e.g., removal of divergence of stress and the natural emergence of a core making redundant the artificial cut-off radius). In the present work we present the gauge field theoretic solution to the problem of a uniformly moving screw dislocation. Apart from the formal derivations, we show that stress divergence at the core of the dislocation is removed at all time and (consistent with atomistic simulations), supersonic states are found to be admissible

  18. Examination of wall functions for a Parabolized Navier-Stokes code for supersonic flow

    Energy Technology Data Exchange (ETDEWEB)

    Alsbrooks, T.H. [New Mexico Univ., Albuquerque, NM (United States). Dept. of Mechanical Engineering

    1993-04-01

    Solutions from a Parabolized Navier-Stokes (PNS) code with an algebraic turbulence model are compared with wall functions. The wall functions represent the turbulent flow profiles in the viscous sublayer, thus removing many grid points from the solution procedure. The wall functions are intended to replace the computed profiles between the body surface and a match point in the logarithmic region. A supersonic adiabatic flow case was examined first. This adiabatic case indicates close agreement between computed velocity profiles near the wall and the wall function for a limited range of suitable match points in the logarithmic region. In an attempt to improve marching stability, a laminar to turbulent transition routine was implemented at the start of the PNS code. Implementing the wall function with the transitional routine in the PNS code is expected to reduce computational time while maintaining good accuracy in computed skin friction.

  19. Examination of wall functions for a Parabolized Navier-Stokes code for supersonic flow

    Energy Technology Data Exchange (ETDEWEB)

    Alsbrooks, T.H. (New Mexico Univ., Albuquerque, NM (United States). Dept. of Mechanical Engineering)

    1993-01-01

    Solutions from a Parabolized Navier-Stokes (PNS) code with an algebraic turbulence model are compared with wall functions. The wall functions represent the turbulent flow profiles in the viscous sublayer, thus removing many grid points from the solution procedure. The wall functions are intended to replace the computed profiles between the body surface and a match point in the logarithmic region. A supersonic adiabatic flow case was examined first. This adiabatic case indicates close agreement between computed velocity profiles near the wall and the wall function for a limited range of suitable match points in the logarithmic region. In an attempt to improve marching stability, a laminar to turbulent transition routine was implemented at the start of the PNS code. Implementing the wall function with the transitional routine in the PNS code is expected to reduce computational time while maintaining good accuracy in computed skin friction.

  20. Integration of Multifidelity Multidisciplinary Computer Codes for Design and Analysis of Supersonic Aircraft

    Science.gov (United States)

    Geiselhart, Karl A.; Ozoroski, Lori P.; Fenbert, James W.; Shields, Elwood W.; Li, Wu

    2011-01-01

    This paper documents the development of a conceptual level integrated process for design and analysis of efficient and environmentally acceptable supersonic aircraft. To overcome the technical challenges to achieve this goal, a conceptual design capability which provides users with the ability to examine the integrated solution between all disciplines and facilitates the application of multidiscipline design, analysis, and optimization on a scale greater than previously achieved, is needed. The described capability is both an interactive design environment as well as a high powered optimization system with a unique blend of low, mixed and high-fidelity engineering tools combined together in the software integration framework, ModelCenter. The various modules are described and capabilities of the system are demonstrated. The current limitations and proposed future enhancements are also discussed.

  1. Error analysis of supersonic air-to-air ejector schlieren pictures

    Directory of Open Access Journals (Sweden)

    Kolář J.

    2013-04-01

    Full Text Available The scope of this article is focused on general analysis of errors and uncertainties possibly arising from CFD-to-schlieren pictures matching. Analysis is based on classic analytical equations. These are firstly evaluated with the presumption of constant density gradient along the ray course. In other words, the deflection of light-ray caused by density gradient is negligible in compare to the cross size of constant gradient area. It is the aim of this work to determine, whether this presumption is applicable in case of supersonic air-to-air ejector. The colour and black and white schlieren pictures are carried out and compared to CFD results. Simulations had covered various eddy viscosities. Computed pressure gradients are transformed into deflection angles and further to ray displacement. Resulting computed light- ray deflection is matched to experimental results

  2. Experimental approach of plasma supersonic expansion physics and of Hall effect propulsion systems

    International Nuclear Information System (INIS)

    Mazouffre, Stephane

    2009-01-01

    This report for accreditation to supervise research (HDR) proposes a synthesis of scientific and research works performed by the author during about ten years. Thus, a first part addresses studies on plasma rarefied supersonic flows: expansion through a sonic hole and through a Laval nozzle. The next part addresses the study of plasma propulsion for spacecraft, and more particularly electric propulsion based on the Hall effect: phenomena of ionic and atomic transport, characteristics of the electric field, energy deposition on walls, basic scale laws, related works, hybrid Hall-RF propulsion systems. The third part presents perspectives and projects related to propulsion by Hall effect (research topics, planned researches, a European project on high power, hybrid Hall-RF propulsion) and to ions-ions plasma (the PEGASES concept, the NExET test installation, RF source of negative ions and magnetic trap)

  3. Mitigate the tent-induced perturbation in ignition capsules by supersonic radiation propagation

    Science.gov (United States)

    Dai, Zhensheng; Gu, Jianfa; Zheng, Wudi

    2017-10-01

    In the inertial confinement fusion (ICF) scheme, to trap the alpha particle products of the D-T reaction, the capsules needs to be imploded and compressed with high symmetry In the laser indirect drive scheme, the capsules are held at the center of high-Z hohlraums by thin membranes (tents). However, the tents are recognized as one of the most important contributors to hot spot asymmetries, areal density perturbations and reduced performance. To improve the capsule implosion performance, various alternatives such as the micro-scale rods, a larger fill-tube and a low-density foam layer around the capsule have been presented. Our simulations show that the radiation propagates supersonically in the low-density foam layer and starts to ablate the capsule before the perturbations induced by the tents reach the ablating fronts. The tent induced perturbations are remarkably weakened when they are propagating in the blow-off plasma.

  4. LES of Supersonic Turbulent Channel Flow at Mach Numbers 1.5 and 3

    Science.gov (United States)

    Raghunath, Sriram; Brereton, Giles

    2009-11-01

    LES of compressible, turbulent, body-force driven, isothermal-wall channel flows at Reτ of 190 and 395 at moderate supersonic speeds (Mach 1.5 and 3) are presented. Simulations are fully resolved in the wall-normal direction without the need for wall-layer models. SGS models for incompressible flows, with appropriate extensions for compressibility, are tested a priori/ with DNS results and used in LES. Convergence of the simulations is found to be sensitive to the initial conditions and to the choice of model (wall-normal damping) in the laminar sublayer. The Nicoud--Ducros wall adapting SGS model, coupled with a standard SGS heat flux model, is found to yield results in good agreement with DNS.

  5. Experimental Performance Evaluation of a Supersonic Turbine for Rocket Engine Applications

    Science.gov (United States)

    Snellgrove, Lauren M.; Griffin, Lisa W.; Sieja, James P.; Huber, Frank W.

    2003-01-01

    In order to mitigate the risk of rocket propulsion development, efficient, accurate, detailed fluid dynamics analysis and testing of the turbomachinery is necessary. To support this requirement, a task was developed at NASA Marshall Space Flight Center (MSFC) to improve turbine aerodynamic performance through the application of advanced design and analysis tools. These tools were applied to optimize a supersonic turbine design suitable for a reusable launch vehicle (RLV). The hot gas path and blading were redesigned-to obtain an increased efficiency. The goal of the demonstration was to increase the total-to- static efficiency of the turbine by eight points over the baseline design. A sub-scale, cold flow test article modeling the final optimized turbine was designed, manufactured, and tested in air at MSFC s Turbine Airflow Facility. Extensive on- and off- design point performance data, steady-state data, and unsteady blade loading data were collected during testing.

  6. Design and test of a 10kW ORC supersonic turbine generator

    Science.gov (United States)

    Seume, J. R.; Peters, M.; Kunte, H.

    2017-03-01

    Manufactures are searching for possibilities to increase the efficiency of combustion engines by using the remaining energy of the exhaust gas. One possibility to recover some of this thermal energy is an organic Rankine cycle (ORC). For such an ORC running with ethanol, the aerothermodynamic design and test of a supersonic axial, single stage impulse turbine generator unit is described. The blade design as well as the regulation by variable partial admission is shown. Additionally the mechanical design of the directly coupled turbine generator unit including the aerodynamic sealing and the test facility is presented. Finally the results of CFD-based computations are compared to the experimental measurements. The comparison shows a remarkably good agreement between the numerical computations and the test data.

  7. Computational Fluid Dynamics Modeling of a Supersonic Nozzle and Integration into a Variable Cycle Engine Model

    Science.gov (United States)

    Connolly, Joseph W.; Friedlander, David; Kopasakis, George

    2015-01-01

    This paper covers the development of an integrated nonlinear dynamic simulation for a variable cycle turbofan engine and nozzle that can be integrated with an overall vehicle Aero-Propulso-Servo-Elastic (APSE) model. A previously developed variable cycle turbofan engine model is used for this study and is enhanced here to include variable guide vanes allowing for operation across the supersonic flight regime. The primary focus of this study is to improve the fidelity of the model's thrust response by replacing the simple choked flow equation convergent-divergent nozzle model with a MacCormack method based quasi-1D model. The dynamic response of the nozzle model using the MacCormack method is verified by comparing it against a model of the nozzle using the conservation element/solution element method. A methodology is also presented for the integration of the MacCormack nozzle model with the variable cycle engine.

  8. A photoionization study of hydrogen-bound clusters in a supersonic molecular beam

    International Nuclear Information System (INIS)

    Cook, K.D.; Jones, G.G.; Taylor, J.W.

    1980-01-01

    Hydrogen bonding of methanol, methanol-d, ethanol, and trifluoroethanol is investigated with a supersonic molecular beam as a sampling system for a photoionization quadrupole mass spectrometer. Monochromatized vacuum ultraviolet synchrotron radiation is used as the ionizing source. Cluster ions belonging to the series (ROH)sub(n)H + are detected when sampling up to 100-torr alcohol vapor with the molecular beam. No parent cluster molecular ions are detected. Experiments are described which exclude ion-molecule reactions in the mass spectrometer ion source as a possible origin of the cluster ions. Experimental evidence shows that nozzle temperature primarily influences the equilibrium distribution of clusters present in the nozzle source. From the dependences of relative cluster ion intensities on nozzle source temperature, the heats of formation of oligomers of the alcohols are estimated. Cooperative hydrogen bonding is not detected, expect for trifluoroethanol, where the trimer is found to be the most stable cluster. (orig.)

  9. Nanomanufacturing of titania interfaces with controlled structural and functional properties by supersonic cluster beam deposition

    International Nuclear Information System (INIS)

    Podestà, Alessandro; Borghi, Francesca; Indrieri, Marco; Bovio, Simone; Piazzoni, Claudio; Milani, Paolo

    2015-01-01

    Great emphasis is placed on the development of integrated approaches for the synthesis and the characterization of ad hoc nanostructured platforms, to be used as templates with controlled morphology and chemical properties for the investigation of specific phenomena of great relevance in interdisciplinary fields such as biotechnology, medicine, and advanced materials. Here, we discuss the crucial role and the advantages of thin film deposition strategies based on cluster-assembling from supersonic cluster beams. We select cluster-assembled nanostructured titania (ns-TiO 2 ) as a case study to demonstrate that accurate control over morphological parameters can be routinely achieved, and consequently, over several relevant interfacial properties and phenomena, like surface charging in a liquid electrolyte, and proteins and nanoparticles adsorption. In particular, we show that the very good control of nanoscale morphology is obtained by taking advantage of simple scaling laws governing the ballistic deposition regime of low-energy, mass-dispersed clusters with reduced surface mobility

  10. Accounting for Laminar Run & Trip Drag in Supersonic Cruise Performance Testing

    Science.gov (United States)

    Goodsell, Aga M.; Kennelly, Robert A.

    1999-01-01

    An improved laminar run and trip drag correction methodology for supersonic cruise performance testing was derived. This method required more careful analysis of the flow visualization images which revealed delayed transition particularly on the inboard upper surface, even for the largest trip disks. In addition, a new code was developed to estimate the laminar run correction. Once the data were corrected for laminar run, the correct approach to the analysis of the trip drag became evident. Although the data originally appeared confusing, the corrected data are consistent with previous results. Furthermore, the modified approach, which was described in this presentation, extends prior historical work by taking into account the delayed transition caused by the blunt leading edges.

  11. Fail-safe system for activity cooled supersonic and hypersonic aircraft. [using liquid hydrogen fuel

    Science.gov (United States)

    Jones, R. A.; Braswell, D. O.; Richie, C. B.

    1975-01-01

    A fail-safe-system concept was studied as an alternative to a redundant active cooling system for supersonic and hypersonic aircraft which use the heat sink of liquid-hydrogen fuel for cooling the aircraft structure. This concept consists of an abort maneuver by the aircraft and a passive thermal protection system (TPS) for the aircraft skin. The abort manuever provides a low-heat-load descent from normal cruise speed to a lower speed at which cooling is unnecessary, and the passive TPS allows the aircraft skin to absorb the abort heat load without exceeding critical skin temperature. On the basis of results obtained, it appears that this fail-safe-system concept warrants further consideration, inasmuch as a fail-safe system could possibly replace a redundant active cooling system with no increase in weight and would offer other potential advantages.

  12. Insulation systems for liquid methane fuel tanks for supersonic cruise aircraft

    Science.gov (United States)

    Brady, H. F.; Delduca, D.

    1972-01-01

    Two insulation systems for tanks containing liquid methane in supersonic cruise-type aircraft were designed and tested after an extensive materials investigation. One system is an external insulation and the other is an internal wet-type insulation system. Tank volume was maximized by making the tank shape approach a rectangular parallelopiped. One tank was designed to use the external insulation and the other tank to use the internal insulation. Performance of the external insulation system was evaluated on a full-scale tank under the temperature environment of -320 F to 700 F and ambient pressures of ground-level atmospheric to 1 psia. Problems with installing the internal insulation on the test tank prevented full-scale evaluation of performance; however, small-scale testing verified thermal conductivity, temperature capability, and installed density.

  13. Experimental study on electrostatic guiding of supersonic D2O molecular beam with two charged wires

    International Nuclear Information System (INIS)

    Yin Yaling; Xia Yong; Chen Haibo; Yin Jianping

    2007-01-01

    We demonstrate the guiding of a supersonic heavy-water (D 2 O) molecular beam using a hollow electrostatic field generated by the combination of two parallel charged-wires and two grounded metal-plates, and report some new and preliminary experimental results. In the experiment, we detect the guiding signals by using the method of time-of-flight mass spectrum and study the dependence of the relative transmission of the beam guide on the guiding voltage. Our study shows that the relative transmission of the beam guide is increased linearly with increasing guiding voltage V guid , and the number of the guided D 2 O molecules is at least increased by 89.4% when the guiding voltage is +20.0 kV. Finally, some potential applications of our guiding scheme in the molecule optics are briefly discussed. (authors)

  14. Supersonic flow over a pitching delta wing using surface pressure measurements and numerical simulations

    Directory of Open Access Journals (Sweden)

    Mostafa HADIDOOLABI

    2018-01-01

    Full Text Available Experimental and numerical methods were applied to investigating high subsonic and supersonic flows over a 60° swept delta wing in fixed state and pitching oscillation. Static pressure coefficient distributions over the wing leeward surface and the hysteresis loops of pressure coefficient versus angle of attack at the sensor locations were obtained by wind tunnel tests. Similar results were obtained by numerical simulations which agreed well with the experiments. Flow structure around the wing was also demonstrated by the numerical simulation. Effects of Mach number and angle of attack on pressure distribution curves in static tests were investigated. Effects of various oscillation parameters including Mach number, mean angle of attack, pitching amplitude and frequency on hysteresis loops were investigated in dynamic tests and the associated physical mechanisms were discussed. Vortex breakdown phenomenon over the wing was identified at high angles of attack using the pressure coefficient curves and hysteresis loops, and its effects on the flow features were discussed.

  15. Steady, Oscillatory and Unsteady, Subsonic and Supersonic Aerodynamics (SOUSSA) for complex aircraft configurations

    Science.gov (United States)

    Morino, L.; Tseng, K.

    1978-01-01

    The Green's function method and the computer program SOUSSA (Steady Oscillatory and Unsteady Subsonic and Supersonic Aerodynamics) are reviewed. The Green's function method is applied to the fully unsteady potential equation yielding an integro-differential-delay equation. This equation is approximated by a set of differential-delay equations in time using the finite element method. The Laplace transform is used to yield a matrix relating the velocity potential to the normal wash. The matrix of the generalized aerodynamic forces is obtained by premultiplying and postmultiplying the matrices relating generalized forces to the potential and the normal wash by the generalized coordinates. The program SOUSSA is compared with existing numerical results. Results indicate that the program is not only general, flexible, and easy to use, but also accurate and fast.

  16. The Generation, Radiation and Prediction of Supersonic Jet Noise. Volume 1

    Science.gov (United States)

    1978-10-01

    supersonic Jet noise, the U. S. Air Force and the U. S. Department of Transportation Jointly Initiated a series of research contracts directed toward this need...ofMeasurdUAiDigPNOLE Specta an PreictiosDBaedLo 9ih0eqec LiEDICTIEquation Solutos eimTmeaueJt TP 80.Mthd1 *7 60 .........em131 1 (a 6300 I dB 100 90j 80...C3 - -21 Vjm 2Ao/a, a 2 de C4 - 21 Z- Ao, C5 - - 2IH 2VIMM6, and C6 - iVAob/. The form of j, for r >r m may be found by substituting Equation (3-107

  17. Doppler-shifted fluorescence imaging of velocity fields in supersonic reacting flows

    Science.gov (United States)

    Allen, M. G.; Davis, S. J.; Kessler, W. J.; Sonnenfroh, D. M.

    1992-01-01

    The application of Doppler-shifted fluorescence imaging of velocity fields in supersonic reacting flows is analyzed. Focussing on fluorescence of the OH molecule in typical H2-air Scramjet flows, the effects of uncharacterized variations in temperature, pressure, and collisional partner composition across the measurement plane are examined. Detailed measurements of the (1,0) band OH lineshape variations in H2-air combustions are used, along with single-pulse and time-averaged measurements of an excimer-pumped dye laser, to predict the performance of a model velocimeter with typical Scramjet flow properties. The analysis demonstrates the need for modification and control of the laser bandshape in order to permit accurate velocity measurements in the presence of multivariant flow properties.

  18. Numerical simulation of supersonic over/under expanded jets using adaptive grid

    International Nuclear Information System (INIS)

    Talebi, S.; Shirani, E.

    2001-05-01

    Numerical simulation of supersonic under and over expanded jet was simulated. In order to achieve the solution efficiently and with high resolution, adaptive grid is used. The axisymmetric compressible, time dependent Navier-Stokes equations in body fitted curvilinear coordinate were solved numerically. The equations were discretized by using control volume, and the Van Leer flux splitting approach. The equations were solved implicitly. The obtained computer code was used to simulate four different cases of moderate and strong under and over expanded jet flows. The results show that with the adaptation of the grid, the various features of this complicated flow can be observed. It was shown that the adaptation method is very efficient and has the ability to make fine grids near the high gradient regions. (author)

  19. New Model Exhaust System Supports Testing in NASA Lewis' 10- by 10-Foot Supersonic Wind Tunnel

    Science.gov (United States)

    Roeder, James W., Jr.

    1998-01-01

    In early 1996, the ability to run NASA Lewis Research Center's Abe Silverstein 10- by 10- Foot Supersonic Wind Tunnel (10x10) at subsonic test section speeds was reestablished. Taking advantage of this new speed range, a subsonic research test program was scheduled for the 10x10 in the fall of 1996. However, many subsonic aircraft test models require an exhaust source to simulate main engine flow, engine bleed flows, and other phenomena. This was also true of the proposed test model, but at the time the 10x10 did not have a model exhaust capability. So, through an in-house effort over a period of only 5 months, a new model exhaust system was designed, installed, checked out, and made ready in time to support the scheduled test program.

  20. Modified k-l model and its ability to simulate supersonic axisymmetric turbulent flows

    International Nuclear Information System (INIS)

    Ahmadikia, H.; Shirani, E.

    2001-05-01

    The k-l turbulence model is a promising two-equation model. In this paper, the k and l model equations were derived from k-kl incompressible and one-equation turbulent models. Then the model was modified for compressible and transitional flows, and was applied to simulate supersonic axisymmetric flows over Hollow cylinder flare an hyperboloid flare bodies. The results were compared with the results obtained for the same flows experimentally as well as k-ε, k-ω and Baldwin-Lomax models. It was shown that the k-l model produces good results compared with experimental data and numerical data obtained when other turbulence models were used. It gives better results than k-ω and k-ε models in some cases. (author)