This report deals with the Aerospace Research Laboratories' (ARL) efforts in achieving thrust augmentation for air-breathing propulsion systems. Qualitative and quantitative analyses of the thrust augmentation process are reported and compared with experimental results. Application of the process to V/STOL propulsion is also discussed.

Topics: DTIC Archive, Campbell, William S, AEROSPACE RESEARCH LABS WRIGHT-PATTERSON AFB OH, *VERTICAL...

The objectives of this program are to determine the local convection heat transfer coefficients in the convergent portion and throat sections of de Laval nozzles; and to determine the effect on the local heat transfer coefficients, particularly at the throat, of varying the contour in the converging section of the nozzle. Three two-dimensional nozzles have been tested. Heat transfer coefficients have been obtained for both the flat and contoured walls.

Topics: DTIC Archive, STANFORD UNIV CA DEPT OF MECHANICAL ENGINEERING, *HEAT TRANSFER COEFFICIENTS, *LAVAL...

We present a new numerical method for calculating an evolving 2-D Hele-Shaw interface when surface tension effects are neglected. In the case where the flow is directed from the less viscous fluid into the more viscous fluid, the motion of the interface is ill-posed; small deviations in the initial condition will produce significant changes in the ensuing motion. This situation is disastrous for numerical computation, as small round-off errors can quickly lead to large inaccuracies in the...

Topics: DTIC Archive, Baker, Gregory, INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING...

Current objectives at NASA Johnson Space Center ate directed at future upgrade and replacement of the U.S. Space Shuttle's, currently toxic, Reaction Control System thrusters with dual mode thrusters that use nontoxic propellants. Experimentation to determine any performance advantages obtained using a dual mode thruster has not been performed by NASA. A computational fluid dynamics analysis is performed to evaluate the internal flow characteristics of this thruster under low thrust mode, torch...

Topics: DTIC Archive, Williams, Adam N., NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *COMPUTATIONAL FLUID...

A description of some experiments involving a two-dimensional, partially cavitating, plano-convex hydrofoil is presented in this report. The data obtained were compared to two theories for two-dimensional partially cavitating flow; the camber line theory of Geurst and the theory for a plano-convex hydrofoil which included the effects of thickness. The latter theory involves assumptions identical to those of Wade, but the solution is purely numerical, being the determination of the strengths of...

Topics: DTIC Archive, Uhlman,James S , Jr, MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING,...

The effects of unsteady modes of motion on two-dimensional transonic flows are investigated. Numerical algorithms that treat shock waves as moving discontinuities are described for nonlinear and time-linearized perturbation flows. Results for transonic flow past an NACA 64A006 airfoil experiencing harmonic motions in one of several modes are presented. (Author)

Topics: DTIC Archive, Seebass,A R, ARIZONA UNIV TUCSON DEPT OF AEROSPACE AND MECHANICAL ENGINEERING,...

An analysis is undertaken, both mathematical and numerical, of the quenching of two-dimensional premixed flames under a variety of circumstances. The discussion is divided into two parts, the first of which deals with quenching due to proximity to a surface through which there are heat losses, the second, quenching due to a shear flow of the kind experienced by a flame attached to a wire. The discussion includes a critical appraisal of flame stretch and the role sometimes claimed for it in...

Topics: DTIC Archive, Buckmaster,J, WISCONSIN UNIV MADISON MATHEMATICS RESEARCH CENTER, *MATHEMATICAL...

A computer code was developed for solving incompressible two- dimensional axisymmetric time-dependent viscous fluid flow problems involving up to two free surfaces. Heuristic models for turbulence are employed to extend the method to indefinitely high Reynolds number. Scalar quantities (heat and solute concentrations) are also followed, and the fluid may be slightly nonhomogeneous in the Boussinesq approximation. The method is a second-order space, forward time explicit finite-difference...

Topics: DTIC Archive, Pritchett, John W, INFORMATION RESEARCH ASSOCIATES INC BERKELEY CA, *NUCLEAR...

Parallel wall inserts were installed in the Naval Ship Research and Development Center 8 x 10-foot subsonic tunnel to create a 3 x 8 foot channel to serve as a high flow quality two-dimensional test section for high lift testing. A detailed flow survey indicated good flow uniformity, negligible angularity, a thin wall boundary layer at the model station, and a pronounced effect of trailing edge wall flaps on controlling test section dynamic pressure. A pair of two-dimensional airfoil sections...

Topics: DTIC Archive, Englar, Robert J, DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA...

A Rayleigh scattering and laser Doppler velocimetry system has been developed for studying the interaction between the vortex street behind a cylinder and a two dimensional plane flame front. Measurements on an open jet methane/air flame stabilized on a heated 0.25 mm platinum wire showed appreciable instabilities in the flame due to the turbulent eddies in the mixing region of the jet. By enclosing the flow in a square channel flame stability was increased. A 3.2 mm diameter cylinder was used...

Topics: DTIC Archive, Namer,I, CALIFORNIA UNIV BERKELEY DEPT OF MECHANICAL ENGINEERING, *CYLINDRICAL...

A computer program is presented for the aerodynamic design of axisymmetric and planar nozzles for supersonic and hypersonic wind tunnels. The program is the culmination of the effort expended at various times over a number of years to develop a method of designing a wind tunnel with an inviscid contour which has continuous curvature and which is corrected for the growth of the boundary layer in a manner such that uniform parallel flow can be expected at the nozzle exit. The continuous curvature...

Topics: DTIC Archive, Sivells, J C, ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN, *COMPUTER AIDED...

This report presents the results of a state-ofthe-art survey on flow- tunnel design and related instrumentation for tunnels using water or liquid nitrogen as the working fluid. The scope of the survey is purposely narrowed by considerations of the proposed tunnel to be designed and built at NASA's George C. Marshall Space Flight Center (MSFC). Initial application of the proposed tunnel will include internal-fluid-flow studies of cryogenic fuel-system components or combinations thereof. Major...

Topics: DTIC Archive, Harp, J L, BATTELLE MEMORIAL INST COLUMBUS OH, *INCOMPRESSIBLE FLOW, *WATER TUNNELS,...

This paper discusses a test that was conducted jointly by Pratt & Whitney Aircraft Engines and NASA Lewis Research Center. The test was conducted in NASA's 9- by 15-Foot Low Speed Wind Tunnel (9x15 LSWT). The test setup, methods, and aerodynamic results of this test are discussed. Acoustical results are discussed in a separate paper by J. Bridges and J. Marino.

Topics: NASA Technical Reports Server (NTRS), PERFORMANCE TESTS, TWO DIMENSIONAL MODELS, NOZZLE GEOMETRY,...

The present work investigates two approaches for force evaluation in the lattice Boltzmann equation: the momentum- exchange method and the stress-integration method on the surface of a body. The boundary condition for the particle distribution functions on curved geometries is handled with second order accuracy based on our recent works. The stress-integration method is computationally laborious for two-dimensional flows and in general difficult to implement for three-dimensional flows, while...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY CONDITIONS, DISTRIBUTION FUNCTIONS, TWO DIMENSIONAL...

Aerodynamic flutter and a re-written computer program for its study are discussed. Data cover: (1) lifting surface theory with boundary layer, (2) incompressible, two dimensional, unsteady flow with control surfaces, (3) improved unsteady theory, (4) combined transonic airfoil thickness and shear layer thickness effects, and (5) bending-torsion flutter calculations.

Topics: NASA Technical Reports Server (NTRS), AIRFOILS, BOUNDARY LAYERS, COMPUTER PROGRAMS, LIFTING BODIES,...

A model is suggested in which some of the important features of the circulating flow inside the two-dimensional near wake are derived by assuming a slow viscous flow. The theory considers the flow away from the body base. It is found that there is a region of constant speed merging, as we go downstream, into a region of stagnation-apex flow. The velocity returning from the rear stagnation point along the center streamline is shown to be a slowly varying function of the 'wedge-angle,' of the...

Topics: NASA Technical Reports Server (NTRS), RECIRCULATIVE FLUID FLOW, STAGNATION POINT, WAKES, BOUNDARY...

The frequent but often unsuspected presence of streamwise vortices in nominally two dimensional laminar and turbulent boundary layers and some of their consequences are described. Since there is no body of systematic information on streamwise vortices imbedded in boundary layers, a number of issues concerning their occurrence and behavior are discussed in the form of a set of succinct observations. Desirable experimental and numerical research to remedy the current lack of knowledge is...

Topics: NASA Technical Reports Server (NTRS), LAMINAR BOUNDARY LAYER, TURBULENT BOUNDARY LAYER, VORTICES,...

A fully explicit two-dimensional flow solver, based on a four-stage Runge-Kutta scheme, was developed and utilized to predict two-dimensional viscous flow through turbomachinery cascades for which experimental data is available. The formulation is applied to the density averaged Navier-Stokes equations. Several features of the technique improve the ability of the code to predict high Reynolds number flows on highly stretched grids. These include a low Reynolds number compressible form of the...

Topics: NASA Technical Reports Server (NTRS), CASCADE FLOW, COMPUTATIONAL FLUID DYNAMICS, FLOW STABILITY,...

Boundary-layer receptivity in the leading edge region for bodies with blunt leading edges is investigated in this research program. Receptivity theory provides the link between the unsteady disturbance environment in the freestream and the initial amplitudes of instability waves in the boundary layer. This is a critical problem which must be addressed in order to develop more accurate prediction methods for boundary-layer transition.

Topics: NASA Technical Reports Server (NTRS), BLASIUS FLOW, BLUNT LEADING EDGES, BOUNDARY LAYER TRANSITION,...

An experimental study of flow over a two-dimensional flat plate-wedge configuration is presented. The investigation encompasses a range of Reynolds numbers characteristics of conditions encountered by deep submersible oceanic vehicles. Flow separation, similar to that found on high speed aircraft control surfaces, is reported and discussed in light of the laminar or transitional nature of the separated shear layer. As discovered in previous high Mach number studies of plate-wedge or ramp...

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER SEPARATION, SEPARATED FLOW, TWO DIMENSIONAL...

We develop a new numerical approach to study the spatially evolving instability of the streamwise dominant flow in the presence of roughness elements. The difficulty in handling the flow over the boundary surface with general geometry is removed by using a new conservative form of the governing equations and an analytical mapping. The numerical scheme uses second-order backward Euler in time, fourth-order central differences in all three spatial directions, and boundary-fitted staggered grids....

Topics: NASA Technical Reports Server (NTRS), BOUNDARY LAYER TRANSITION, FOURIER ANALYSIS, GRID GENERATION...

The objective of the present research is the development and application of efficient adaptive numerical algorithms for the study, via direct numerical simulations, of active vortex generators. We are using innovative computational schemes to investigate flows past complex configurations undergoing arbitrary motions. Some of the questions we try to answer are: Can and how may we control the dynamics of the wake? What is the importance of body shape and motion in the active control of the flow?...

Topics: NASA Technical Reports Server (NTRS), ALGORITHMS, COMPUTATIONAL FLUID DYNAMICS, COMPUTERIZED...

The High Fidelity System Simulation effort has addressed various important objectives to enable additional capability within the NPSS framework. The scope emphasized High Pressure Turbine and High Pressure Compressor components. Initial effort was directed at developing and validating intermediate fidelity NPSS model using PD geometry and extended to high-fidelity NPSS model by overlaying detailed geometry to validate CFD against rig data. Both "feedforward" and feedback"...

Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, SYSTEMS SIMULATION, AIRCRAFT...

Results are presented of the theory of wings and of wing sections which are of immediate practical value. They are proven and demonstrated by the use of the simple conceptions of kinetic energy and momentum only.

Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC FORCES, KINETIC THEORY, MOMENTUM, WING PANELS,...

The Carousel Wind Tunnel (CWT) proposed to study aeolian processes aboard a Space Station consists of two concentric rotating drums. The space between the two drums comprises the wind tunnel section. Differential rates of rotation of the two drums would provide a wind velocity with respect to either drum surface. Preliminary results of measured velocity profiles made in a CWT prototype indicate that the wall bounded boundary layer profiles are suitable to simuate flat plate turbulent boundary...

Topics: NASA Technical Reports Server (NTRS), AEOLIAN TONES, EQUATIONS OF MOTION, GRAVITATIONAL EFFECTS,...

A temporal adaptive algorithm for the time-integration of the two-dimensional Euler or Navier-Stokes equations is presented. The flow solver involves an upwind flux-split spatial discretization for the convective terms and central differencing for the shear-stress and heat flux terms on an unstructured mesh of triangles. The temporal adaptive algorithm is a time-accurate integration procedure which allows flows with high spatial and temporal gradients to be computed efficiently by advancing...

Topics: NASA Technical Reports Server (NTRS), ADAPTIVE CONTROL, AIRFOIL PROFILES, EULER EQUATIONS OF...

The present study is a preliminary investigation into the behavior of the flow within a 28 degree total geometric turning angle hypothetical Mach 10 inlet as calculated with the full three-dimensional Navier-Stokes equations. Comparison between the two-dimensional and three-dimensional solutions have been made. The overall compression is not significantly different between the two-dimensional and center plane three dimensional solutions. Approximately one-half to two-thirds of the inlet flow at...

Topics: NASA Technical Reports Server (NTRS), COMPUTATIONAL FLUID DYNAMICS, HYPERSONIC FLOW, INLET FLOW,...

The purpose of these experiments was to compare turbulence measurements using two types of velocity measurement probes: split-film and x- film. The goal is to determine the turbulent flow regimes where the split-film can be used to replace the x-film. The split-film sensor is composed of two independent films supported by a quartz filament. The split-film's larger diameter makes it less sensitive to high frequency fluctuations than the x-film, but is able to measure higher flow angles than the...

Topics: DTIC Archive, Fisk, Timothy E, AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH SCHOOL OF ENGINEERING,...

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766

Jul 5, 2010
07/10

by
Alterescu, S.; Simmons, P. B.; Schwartz, R. A

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An automated hospital information system that handles all data related to patient-care activities is described. The description is designed to serve as a manual for potential users, nontechnical medical personnel who may use the system. Examples of the system's operation, commentary on the examples, and a complete listing of the system program are included.

Topics: INLET PRESSURE, INTAKE SYSTEMS, COMPRESSION LOADS, INTERNAL PRESSURE, TWO DIMENSIONAL FLOW

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372

Jun 15, 2011
06/11

by
Maddalon, D. V.; Poppen, W. A., Jr

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Considerable progress has been made in the development of perforated suction surface material for laminar flow control applications. Electron-beam perforated titaniuum skin was used as the suction surface. Critical issues related to suction panel manufacturing were identified and largely resolved. The final product included fabrication of a 7-foot chord by 7-foot span perforated laminar flow control wind tunnel model. Techniques used can be adapted to modern aircraft production lines. The...

Topics: APPLICATIONS PROGRAMS (COMPUTERS), FLOW DISTRIBUTION, INVISCID FLOW, KNUDSEN FLOW, MACH NUMBER,...

A similarity approach to characterizing the influence of shocks and compression ramps on flat plate flows is presented. New correlations for laminar compressive interactions on two-dimensional compression ramps and shock impingements for adiabatic walls have been developed that utilize a universal form which is enabled by the discovery of a new similarity parameter of the Navier-Stokes equations. These new correlations have been developed for two-dimensional, laminar adiabatic wall flows over...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH HIGH SPEED SYSTEMS DIV, *ADIABATIC...

The numerical solution techniques, including explicit, point-implicit, and fully implicit schemes, used in a new quasi two-dimensional procedure for the transient solution of real fluid flows in system lines and volumes are presented. The procedure is coupled with a real-fluid properties database so that both compressible and incompressible fluids may be considered using the same code. The procedure has been implemented in Matlab/Simulink as well as Fortran95 to allow for application on a wide...

Topics: DTIC Archive, Davis, Roger L, CALIFORNIA INST OF TECH PASADENA JET PROPULSION LAB, *COMPUTATIONAL...

Chaotic advection has served as the paradigm for mixing in fluid flows with simple time dependence. Its skeletal structure is based on analysis of invariant attracting and repelling manifolds in fluid flows. Here we develop a finite-time theory for two-dimensional incompressible fluid flows with arbitrary time dependence and introduce a new mixing diagnostic based on it. Besides stretching events around attracting and repelling manifolds, this allows us to detect hyperbolic mixing zones. We...

Topics: DTIC Archive, NAVAL RESEARCH LAB STENNIS SPACE CENTER MS, *MIXING, *FLUID FLOW, FORECASTING,...

Numerical studies of time-dependent, two-dimensional, stratified flow of incompressible, viscous, diffusive fluid are described. The particular physical problem which was considered is that of stratified flow over a vertical fence when the motion is impulsively started from rest. A new iterative method was used for numerical integration of the governing equations and was found to be very effective. The method is based on the combination of the Crank-Nicolson method with a strongly implicit...

Topics: DTIC Archive, Lin, Jung-Tai, COLORADO STATE UNIV FORT COLLINS FLUID MECHANICS AND DIFFUSION LAB,...

Shear stress, eddy viscosity, and mixing length distributions corresponding to five two-dimensional, incompressible equilibrium turbulent boundary layers were calculated by substituting measured velocity profile data into the governing equations. The five flows cover the range from moderate adverse pressure gradient to strong favorable pressure gradient.

Topics: DTIC Archive, Glowacki, W J, NAVAL ORDNANCE LAB WHITE OAK MD, *INCOMPRESSIBLE FLOW, *PRESSURE...

This report presents the results of a test program to determine the drag of supersonic inlets operating at transonic Mach number conditions. It is a supplement to Air Force Report AFAPL-TR-68-119 describing the results of additional tests conducted under Air Force Contract F33615-68-C-1520. Data are presented showing the additive drag and total inlet drag of the F-4 aircraft inlet measured in the presence of the aircraft forebody and in an undisturbed stream. Inlet drag test data are also...

Topics: DTIC Archive, McVey, Francis D, MCDONNELL DOUGLAS CORP ST LOUIS MO, *JET FIGHTERS, AXISYMMETRIC...

In this report, the requirements are considered for a two dimensional flow visualization diagnostic capable of non intrusively measuring temperature and species concentration in a turbulent, atmospheric pressure flow tube. The need for and the history of flow visualization techniques are briefly reviewed. A new approach is then suggested, based on optical tomography, that would have several advantages over methods currently under development. An up-to-date reference list for optical tomography...

Topics: DTIC Archive, Beiting, E. J., AEROSPACE CORP EL SEGUNDO CA AEROPHYSICS LAB, *FLOW VISUALIZATION,...

The three partial differential equations of the laminar boundary layer for two-dimensional steady-state compressible flow have been transformed into two ordinary differential equations by the method of Pohlhausen, Falkner, and Skan. The ordinary equations include parameters for expressing the simultaneous effects of pressure gradient in the main-stream flow through a porous wall and property changes in the fluid due to large temperature differences between the wall and the free stream.

Topics: DTIC Archive, Brown, W B, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC, *LAMINAR...

We develop a formulation for the single-fluid/two-temperature equations for simulating two-species, compressible, non-equilibrium plasma flows. The divergence-free condition of the magnetic field is enforced via the characteristic decomposition of an extended nine-wave system. The source terms are modified appropriately to improve energy and momentum conservation accuracy. A spectral/hp element algorithm is employed in the discretization combined with a discontinuous Galerkin formulation for...

Topics: DTIC Archive, Lin, Guang, BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS, *PLASMAS(PHYSICS),...

Tests are reported in which air incidence angle was varied to a cascade of 20 blades, 5 inches in chord with aspect ratio of 2.0 and solidity of 1.67. Preliminary blade element performance data were obtained using pneumatic probe surveys and surface pressures were also measured. Results of preparatory tests of a similar cascade of 15 C-series blades at a solidity of 1.28 are also included. Whereas the flow in the C-series blading cascade was always acceptable, the flow in the DCA blading...

Topics: DTIC Archive, Cina,Frank S, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *TURBINE BLADES, *COMPRESSOR...

There were three major research explorations. (1) Wavelets: Necessary and sufficient conditions on the wavelet, scaling function and projection kernel for given rates of convergence of wavelet expansions in the supremum and L (P) (Rd) norms have been given. (2) Image compression is developed using quasi-interpolant multivariate box splines and multi-resolution analysis has been developed. (3) Shallow Water Theory: A mathematical justification for the "shallow water theory for...

Topics: DTIC Archive, Williams, Daniel A., HOWARD UNIV WASHINGTON DC DEPT OF MATHEMATICS, *DATA...

Turbulence and mean flow measurements were acquired downstream of a normal, supersonic (M=1.6), two-dimensional, slot injection into Mach 3.0 flow (Re/m = 15x10 to the 6th power). Two non-adiabatic cases (Tti/Tt = 1.11 and Tti/Tt = 0.93) were studied. Multiple overheat anemometry and conventional mean flow analysis, as well as shadowgraph and schlieren photography, were utilized to study the turbulent mixing layer. The mean flow data included the Pitot, cone-static, and Mach number profiles....

Topics: DTIC Archive, Tucker, Kelly C., AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF...

The Propeller Force Module (PFM) code developed by Analytical Methods Inc. (AMI) for calculating propeller side forces during maneuvering simulation studies requires inputs of propeller blade sectional lift, drag, and moment data. A set of steady two-dimensional foil force data for NACA profiles is normally used by PFM as input. Wake survey data show that the propeller blade sections will encounter large spatial variations in angle of attack during maneuvers. A literature search is conducted to...

Topics: DTIC Archive, Shen, Young, NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS...

Flow-distribution problems have become increasingly important in the design of modern fluid flow and heat transfer systems. The study of flow-distribution characteristics and control of marine gas turbine exhaust flow is the subject of this report. Major technical problems associated with nonuniform-flow distribution were reviewed and various flow-distribution control methods were evaluated. A two-dimensional, turbulent-flow model was developed for investigating flow-distribution...

Topics: DTIC Archive, Kuo,Simion C, UNITED TECHNOLOGIES RESEARCH CENTER EAST HARTFORD CT, *TURBULENT FLOW,...

Two finite element hydrodynamic models, one for two-dimensional free surface flow in the horizontal plane and one for the vertical plane are being evaluated. Although the models are formulated to solve dynamic flow problems, all work to date has been with steady state solutions. Recent research has focused on mass continuity performance of the models, proper boundary condition specification, and comparison with finite difference techniques. The objective of this research is to develop...

Topics: DTIC Archive, Gee,D Michael, HYDROLOGIC ENGINEERING CENTER DAVIS CA, *TWO DIMENSIONAL FLOW,...

The report discusses the difficulties encountered and their solutions in the development of the computer program for the two-dimensional and axisymmetric fields. Also, the mathematics used in the program are presented. The initial computer program was written for the simple chemical system N2O4 + N2 reversibly yields 2NO2 + N2. This system was chosen so that basic programming difficulties would not be concealed in a maze of chemical reactions. After completion, the program was modified to...

Topics: DTIC Archive, AIR FORCE AERO PROPULSION LAB WRIGHT-PATTERSON AFB OH, *RAMJET ENGINE NOZZLES,...

One method of solving the problem of burning or combustion at supersonic speed is by combusting in a stationary detonation wave. Stabilization of a detonation wave has been recently accomplished and is reproducible, but only in laboratory type apparatus. Using two-dimensional steady flow, perfect gas theory, this paper provides solutions for the changes in properties that may be expected across any oblique detonation wave. Equations are established and solved using the Control Data Corporation...

Topics: DTIC Archive, Gibber, Philip F, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *COMBUSTION, *DETONATION...

A method is proposed to treat the problem of steady, two-dimensional, laminar, incompressible high Reynolds number separated flow past thin airfoils. An integral form of the boundary layer equations with interaction is used and the interaction between the inviscid and viscous flow fields is provided for by use of a thin-airfoil integral. Documentation of the attempts at obtaining a solution is presented. A survey of the current state-of-the-art of problems involving viscous-inviscid...

Topics: NASA Technical Reports Server (NTRS), AIR FLOW, INCOMPRESSIBLE FLOW, THIN AIRFOILS, TWO DIMENSIONAL...

The first phases of a fundamental analytical study of STOL ground effects were presented. Ground effects were studied in two dimensions to establish the importance of nonlinear effects, to examine transient aspects of ascent and descent near the ground, and to study the modelling of the jet impingement on the ground. Powered lift system effects were treated using the jet-flap analogy. The status of a three-dimensional jet-wing ground effect method was presented. It was shown, for...

Topics: NASA Technical Reports Server (NTRS), FLOW THEORY, GROUND EFFECT (AERODYNAMICS), SHORT TAKEOFF...

Two-dimensional magnetohydrodynamic turbulence is explored by means of numerical simulation. Previous analytical theory, based on non-dissipative constants of the motion in a truncated Fourier representation, is verified by following the evolution of highly non-equilibrium initial conditions numerically. Dynamo action (conversion of a significant fraction of turbulent kinetic energy into long-wavelength magnetic field energy) is observed. It is conjectured that in the presence of dissipation...

Topics: NASA Technical Reports Server (NTRS), MAGNETOHYDRODYNAMIC TURBULENCE, MAGNETOHYDRODYNAMICS, TWO...