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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Low density, leading edge bluntness, and ablation effects on wedge induced laminar boundary layer separation at moderate enthalpies in hypersonic flow
Ion current drawn to conducting wedge in collisionless plasma flow, deducing flow velocity and ion number density
Doppler shift measurements with double wedge technique applied to mass motion of air plasma escaping ends of theta pinch
Hypersonic flow over blunted slender wedges, examining contradiction between Chernyi and Cheng integral methods for oscillator behavior of shock shape and pressure
Heat transfer and pressure distributions inside hinge line gap of wedge-flap combination at hypersonic speeds
Wedge induced laminar boundary layer separation on flat plate in low density
Analytic formulation of three wedge angle constraints in trajectory studies
Surface pressures and shock wave shapes on sharp flat plates and wedges in rarefied hypersonic transition flow with emphasis on merged layer regime
Performance characteristics of wedge nozzle for supersonic cruise aircraft
Wind tunnel investigation of laminar, transitional, and turbulent boundary layer profiles on wedge at hypersonic speed to confirm theoretical analysis
Three elements of the apochromatic wedge are assembled by optical molecular contact, eliminating all difficulties and inaccuracies inherent in cement bonding.
Investigation of a hot-film wedge probe in viscoelastic fluids by imposing on the probe a sinusoidal vibration of known amplitude and frequency. Root-mean-square (rms) velocities calculated from the displacement of the probe are compared to rms velocities obtained with a constant temperature anemometer. The tests were performed under turbulent flow conditions and also at flow rates where viscoelastic effects, i.e., decrease of heat transfer rates from the probe to the fluid and drag reduction, were observed. The experimental technique was established by measuring the response of the probe in mineral oil.
The local edge buckling phenomena that can occur along the heated thin edge of a wedge shape airfoil is calculated. Qualitative comparison (qualitative only because the experimental temperature distribution was not measured) is made to the experimentally observed phenomena. The consequences of the assumption of identical vibration and buckling modes is shown by a comparison of results with and without the assumption of mode identity. Computer plots of the elastic surface as local buckling develops with increasing temperature are shown. The calculated, fully developed local edge buckling is compared to a photograph of a fully developed buckling as observed in the laboratory.
The inviscid, interference corner flow generated by two intersecting wedges immersed in a supersonic stream is obtained by use of a second-order, shock-capturing, finite-difference approach. The governing equations are solved iteratively in conical coordinates to yield the flow structure consisting of multiple shock and slip surfaces. The numerical results for shock wave and slip surface position and structure, pitot pressure traverses, and surface pressure distributions are compared with experimental data obtained over a wide range of Reynolds numbers. The comparisons show the best agreement with the high Reynolds number (greater than 3,000,000) results for which the boundary layer is turbulent.
An analytical approximation is obtained to the solution of the equation describing the combined effects of bluntness and boundary-layer displacement on the hypersonic flow over a wedge for the case where the constant parameter in the governing equation, which is proportional to the angle of attack, is greater than zero. It is shown that the approximation has good physical accuracy over the entire range of conditions to which the theory is applicable for positive angle of attack.
The problem of a semi infinite strip containing an edge crack is considered. It is assumed that the strip is loaded by a frictionless rigid wedge pressed into the crack. The resulting crack contact problem is formulated in terms of a system of singular integral equations. The behavior of the solution near the singular points is studied in detail. A series of numerical examples are given and the results are compared with those obtained by the method of boundary collocation and by the simple beam theory.
Transonic tunnel and supersonic pressure tunnel tests were reformed to determine the performance characteristics of twin nonaxisymmetric or two-dimensional nozzles with fixed shrouds and variable-geometry wedges. The effects of thrust vectoring, reversing, and installation of various tails were also studied. The investigation was conducted statically and at flight speeds up to a Mach number of 2.20. The total pressure ratio of the simulated jet exhaust was varied up to approximately 26 depending on Mach number. The Reynolds number per meter varied up to 13.20 x 1 million. An analytical study was made to determine the effect on calculated wave drag by varying the mathematical model used to simulate nozzle jet-exhaust plume.
The problem of a semi-infinite strip containing an edge crack is considered. It is assumed that the strip is loaded by a frictionless rigid wedge pressed into the crack. The resulting crack-contact problem is formulated in terms of a system of singular integral equations. The behavior of the solution near the singular points is studied in detail. A series of numerical examples is given and the results are compared with those obtained by the method of boundary collocation and by the simple beam theory.