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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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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1942

Normal-pressure Tests of Circular Plates with Clamped Edges

A fixture is described for making normal-pressure tests of flat plates 5 inches in diameter in which particular care was taken to obtain rigid clamping at the edges. Results are given for 19 plates, ranging in thickness from 0.015 to 0.072 inch. The center deflections and the extreme-fiber stresses at low pressures were found to agree with theoretical values; the center deflections at high pressures were 4 to 12 percent greater than the theoretical values. Empirical curves are derived of the pressure for the beginning of permanent set as a function of the dimensions of the plate and the tensile properties of the material.

CIRCULAR↗
NASA NTRS1942

Normal-Pressure Tests of Rectangular Plates

Report presents the results of normal-pressure tests made of 56 rectangular plates with clamped edges and of 5 plates with freely supported edges. Pressure was applied and the center deflection and the permanent set at the center were measured. For some of the plates, in addition, strains and contours were measured.

Ramberg, Walter↗
NASA NTRS1942

Normal-Pressure Tests of Circular Plates with Clamped Edges

A fixture is described for making normal-pressure tests of flat plates 5 inches in diameter in which particular care was taken to obtain rigid clamping at the edges. Results are given for 19 plates, ranging in thickness form 0.015 to 0.072 inch. The center deflections and the extreme-fiber stresses at low pressures were found to agree with theoretical values; the center deflections at high pressures were 4 to 12 percent greater than the theoretical values. Empirical curves are derived of the pressure for the beginning of the permanent set as a function of the dimensions of the plate and the tensile properties of the material.

Mcpherson, Albert E↗
NASA NTRS1978

Experimental investigation of effects of jet decay rate on jet-induced pressures on a flat plate: Tabulated data

Tabular data are presented for an experimental study of the effects of jet decay rate on the jet-induced pressure distribution on a flat plate for a single jet issuing at right angle to the flat plate into a uniform crossflow. The data are presented in four sections: (1) presents the static nozzle calibration data; (2) lists the plate surface static pressure data and integrated loads; (3) lists the jet centerline trajectory data; and (4) lists the centerline dynamic pressure data.

Kuhlman, J. M.↗
NASA NTRS1975

An experimental investigation of heat transfer to reusable surface insulation tile array gaps in a turbulent boundary layer with pressure gradient

An experimental investigation was performed to determine the effect of pressure gradient on the heat transfer to space shuttle reusable surface insulation (RSI) tile array gaps under thick, turbulent boundary layer conditions. Heat transfer and pressure measurements were obtained on a curved array of full-scale simulated RSI tiles in a tunnel wall boundary layer at a nominal freestream Mach number of 10.3 and freestream unit Reynolds numbers of 1.6, 3.3, and and 6.1 million per meter. Transverse pressure gradients were induced over the model surface by rotating the curved array with respect to the flow. Definition of the tunnel wall boundary layer flow was obtained by measurement of boundary layer pitot pressure profiles, and flat plate wall pressure and heat transfer. Flat plate wall heat transfer data were correlated and a method was derived for prediction of smooth, curved array heat transfer in the highly three-dimensional tunnel wall boundary layer flow and simulation of full-scale space shuttle vehicle pressure gradient levels was assessed.

Throckmorton, D. A.↗
NASA NTRS1978

Pressure pulsations on a flat plate normal to an underexpanded supersonic jet

An experiment was devised to study the interaction between an underexpanded supersonic gas jet and a flat plate, with the plate located in a region in which the interaction produces shock wave and flow fluctuations. Nitrogen gas at ambient stagnation temperature flowed through a convergent nozzle with exit diameter of 2.03 cm and impinged on a square metal plate normal to the jet. Results revealed local peak pressure fluctuations on the plate at nozzle pressure ratios of about 2 and 4.5, with the latter case producing fluctuations of the same order as the mean pressure on the plate; the frequency of the oscillations was as large as 20 kHz. For choked jet flow at ambient pressure higher than atmospheric, the pressure fluctuations would increase accordingly, and adjacent solid structures would therefore be subjected to proportionately higher normal stresses.

Back, L. H.↗
NASA NTRS1985

Effects of velocity profile and inclination on dual-jet-induced pressures on a flat plate in a crosswind

An experimental study was conducted to determine surface pressure distributions on a flat plate with dual subsonic, circular jets exhausting from the surface into a crossflow. The jets were arranged in both side-by-side and tandem configurations and were injected at 90 deg and 60 deg angles to the plate, with jet-to-crossflow velocity ratio of 2.2 and 4. The major objective of the study was to determine the effect of a nonuniform (vs uniform) jet velocity profile, simulating the exhaust of a turbo-fan engine. Nonuniform jets with a high-velocity outer annulus and a low-velocity core induced stronger negative pressure fields than uniform jets with the same mass flow rate. However, nondimensional lift losses (lift loss/jet thrust lift) due to such nonuniform jets were lower than lift losses due to uniform jets. Changing the injection angle from 90 deg to 60 deg resulted in moderate (for tandem jets) to significant (for side-by-side jets) increases in the induced negative pressures, even though the surface area influenced by the jets tended to reduce as the angle decreased. Jets arranged in the side-by-side configuration led to significant jet-induced lift losses exceeding, in some cases, lift losses reported for single jets.

Jakubowski, A. L.↗
NASA NTRS1987

Experimental studies on the tripping behavior of narrow T-stiffened flat plates subjected to hydrostatic pressure and underwater shock

An experimental investigation was conducted to determine the static and dynamic responses of a specific stiffened flat plate design. The air-backed rectangular flat plates of 6061-T6 aluminum with an externally machined longitudinal narrow-flanged T-stiffener and clamped boundary conditions were subjected to static loading by water hydropump pressure and shock loading from an eight pound TNT charge detonated underwater. The dynamic test plate was instrumented to measure transient strains and free field pressure. The static test plate was instrumented to measure transient strains, plate deflection, and pressure. Emphasis was placed upon forcing static and dynamic stiffener tripping, obtaining relevant strain and pressure data, and studying the associated plate-stiffener behavior.

Budweg, H. L.↗
NASA NTRS1978

Experimental investigation of effect of jet decay rate on jet-induced pressures on a flat plate

An experimental study of the interaction between a lift jet and an aircraft wing for a jet VTOL aircraft was performed for the simplified model of an unheated, subsonic, circular jet exiting at right angles to a flat plate into a uniform subsonic crosswind. The effects of jet dynamic pressure decay rate upon the jet location and jet induced pressure distribution on the plate were studied over a range of jet to crossflow velocity ratios of 2.2 or = R or = 10. Jet decay rate was varied through use of cylindrical centerbodies with flat or hemispherical tips submerged in the jet nozzle at various depths below the jet exit plane. Quicker jet dynamic pressure decay, caused by the presence of a centerbody, resulted in reductions in the jet induced lift loss by as much as 45 percent relative to values for jets with no centerbody. These reductions in lift loss were observed at the larger values of crossflow velocity.

Kuhlman, J. M.↗
NASA NTRS1985

The construction of airfoil pressure models by the plate method: Achievements, current research, technology development and potential applications

A method of constructing airfoils by inscribing pressure channels on the face of opposing plates, bonding them together to form one plate with integral channels, and contour machining this plate to form an airfoil model is described. The research and development program to develop the bonding technology is described as well as the construction and testing of an airfoil model. Sample aerodynamic data sets are presented and discussed. Also, work currently under way to produce thin airfoils with camber is presented. Samples of the aft section of a 6 percent airfoil with complete pressure instrumentation including the trailing edge are pictured and described. This technique is particularly useful in fabricating models for transonic cryogenic testing, but it should find application in a wide ange of model construction projects, as well as the fabrication of fuel injectors, space hardware, and other applications requiring advanced bonding technology and intricate fluid passages.

Lawing, P. L.↗
NASA NTRS1976

The nonlinear transient response of thin, rectangular elastic plates

The results of experiments and theoretical analysis of the nonlinear, transient response of thin, rectangular, elastic, simply supported plates are presented. In the experiments, a plane wave tube with a special pulse generator at one end and a thin glass plate mounted at the other end was used to subject the glass plate to pressure pulses of different magnitudes. Whole-field measurements of the response of the plate were obtained by the reflected moire grid technique. The largest ratio of center deflection to thickness of the plate during the experiments was 5.6. The theoretical response of the glass plate to the pressure pulses was computed by solving the von Karman equations governing large deflections in elastic plates by two methods - (1) the finite-difference method, and (2) Galerkin's method. Good agreement was found between theoretically predicted and experimentally measured response.

Rajagopal, G.↗
NASA NTRS1978

A correlation method to predict the surface pressure distribution on an infinite plate from which a jet is issuing

A correlation method to predict pressures induced on an infinite plate by a jet issuing from the plate into a subsonic free stream was developed. The complete method consists of an analytical method which models the blockage and entrainment properties of the jet and a correlation which accounts for the effects of separation. The method was developed for jet velocity ratios up to ten and for radial distances up to five diameters from the jet. Correlation curves and data comparisons are presented for jets issuing normally from a flat plate with velocity ratios one to twelve. Also, a list of references which deal with jets in a crossflow is presented.

Perkins, S. C., Jr.↗