Magnetic field reduction in an expandable superconducting enclosure.
Trapped magnetic field intensity reduced in flexible walled superconducting enclosure of variable cross section
MAGNETIC FIELD INTENSITY↗
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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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Accurate surface temperature measurements at liquid helium conditions in space environment facilities
Germanium resistance thermometer, lead wire heat sink, and high thermal conducting epoxy fastening techniques to measure wall temperature in cryogenically cooled space simulators
Cassidy, J. F.↗
A dielectric-coated circumferential slot array for omnidirectional coverage at microwave frequencies.
Dielectric coated resonant array of circumferential shunt slots cut into broad wall of ring waveguide for omnidirectional coverage at microwave frequencies
Croswell, W. F.↗
Monitoring of crack growth in Ti-Al-4v alloy by the stress wave analysis technique
Stress wave analysis techniques for monitoring crack growth in Ti-6Al-4V alloy pressure vessel walls
Crimmins, P. P.↗
Portable alignment tool Patent
Portable device for aligning surfaces of two adjacent wall or sheet sections for joining at point of junction
Franklin, W. J.↗
Materials technology advancement program for expandable manned space structures Summary report
Composite materials testing for fire resistant wall structures for expandable manned space structures
Cordier, K. L.↗
Integrating sphere theory
Integrating sphere theory with wall mounted specular sample in reflectance and transmittance measurements
Finkel, M. W.↗
Aeroelastic stability of plates and cylinders
Thin plates and thin walled cylinders aeroelastic stability in fluid flow, analyzing panel flutter
Anderson, W. J.↗
Transmission of sound in ducts with thin shear layers - Convergence to the uniform flow case.
The problem of the transmission of sound in a duct with very thin shear layers at the walls is treated by an inner expansion method. The results show that the formulation of the problem of the transmission of sound in a duct with a shear layer at the wall converges, in the case of a vanishingly thin shear layer, to the formulation of the same problem when uniform flow is assumed and the wall boundary condition is that of continuity of particle displacement.
Eversman, W.↗
Experimental evaluation of a 600 lbf spacecraft rocket engine.
Experimental results are presented for a long-duration-capability (1000-sec), space-storable, bipropellant liquid rocket motor burning fluorine/hydrazine or FLOX/monomethylhydrazine. The interrelationship between injected mixture ratio and the per cent film cooling on vacuum specific impulse performance and chamber heat transfer is given. Experimental sea level measurements are used to predict space vacuum performance based upon simplified JANNAF reference procedures. Dynamic combustion stability is demonstrated over a wide range of operating conditions. Analytical results of char penetration, erosion, and ablative wall temperature distributions are presented for prototype chamber designs.
Hoehn, F. W.↗
Control of supersonic wind-tunnel noise by laminarization of nozzle-wall boundary layer
One of the principal design requirements for a quiet supersonic or hypersonic wind tunnel is to maintain laminar boundary layers on the nozzle walls and thereby reduce disturbance levels in the test flow. The conditions and apparent reasons for laminar boundary layers which have been observed during previous investigations on the walls of several nozzles for exit Mach numbers from 2 to 20 are reviewed. Based on these results, an analysis and an assessment of nozzle design requirements for laminar boundary layers including low Reynolds numbers, high acceleration, suction slots, wall temperature control, wall roughness, and area suction are presented.
Beckwith, I. E.↗
Pipe flow measurements of turbulence and ambiguity using laser-Doppler velocimetry
The laser-Doppler ambiguities predicted by George and Lumley (1973) have been verified experimentally for turbulent pipe flows. Experiments were performed at Reynolds numbers from 5000 to 15,000 at the center line and near the wall. Ambiguity levels were measured from power spectral densities of FM demodulated laser signals and were compared with calculations based on the theory. The turbulent spectra for these water flows after accounting for the ambiguity were equivalent to hot-film measurements at similar Reynolds numbers. The feasibility of laser-Doppler measurements very close to the wall in shear flows is demonstrated.
Berman, N. S.↗
The application of holography to the visualization of shock patterns in a transonic compressor
This paper describes an experiment in the application of holographic interferometry to the visualization of flow in a transonic compressor. The principal objective of the study was to visualize the shock waves created by the rotor blades and to determine their relative orientation in three dimensions. The technique employed double-pulse, double-exposure holography to record the flow field through a plastic window built into the outer case over the rotor blades. Illumination was by diffuse reflection from the interior surfaces of the compressor. No other optical components in or on the compressor were used. The resulting holograms successfully showed the upstream bow shocks and, at high speed, the outer-most portion of the leading edge passage shock. Techniques were devised for locating these shocks in three dimensions and the results were compared with theoretical predictions. In all cases, the shock angles were somewhat larger than predicted by theory, and a distinct increase in angle near the outer wall was observed, which may be attributed to end wall boundary layer effects.
Hantman, R. G.↗
Concorde noise-induced building vibrations, John F. Kennedy International Airport
The outdoor/indoor noise levels and associated vibration levels resulting from aircraft and nonaircraft events were recorded at eight homesites and a school. In addition, limited subjective tests were conducted to examine the human detection/annoyance thresholds for building vibration and rattle caused by aircraft noise. Presented herein are the majority of the window and wall vibration data recorded during Concorde and subsonic aircraft overflights.
Mayes, W. H.↗
The response of a disturbed pipe flow to an upstanding roughness element
The paper describes measurements of mean velocity, turbulence intensity and Reynolds shear stress made downstream of a ring-type roughness element of rectangular cross section situated downstream of an identical element. The distance between the elements was varied, and velocity and turbulence profiles in the wake of the downstream element are compared with wake profiles behind a single element. The results show that the leading element can increase the power law exponent of the velocity profile as the spacing between elements is reduced. Turbulence generated in the wake of the first element raises turbulence intensity in the outer region of the wake of the second. The internal boundary layer originating with the second element grows at a rate which depends on the spacing. It is postulated that the internal boundary layers of subsequent roughness elements are determinants in the formation of a periodic wall layer.
Chang, J.↗
Design, fabrication, and bench testing of a solar chemical receiver
Solar thermal energy can be effectively collected, transported, stored, and utilized by means of a chemical storage and transport system employing the reversible SO2 oxidation reaction. A solar chemical receiver for SO3 thermal decomposition to SO2 and oxygen was analyzed. Bench tests of a ten foot section of a receiver module were conducted with dissociated sulfuric acid (SO3 and H2O) in an electrical furnace. Measured percent conversion of SO3 was 85% of the equilibrium value. Methods were developed to fabricate and assemble a complete receiver module. These methods included applying an aluminide coating to certain exposed surfaces, assembling concentric tubes with a wire spacer, applying a platinum catalyst to the tubing wall, and coiling the entire assembly into the desired configuration.
Summers, W. A.↗
Dynamic behavior of an unsteady trubulent boundary layer
Experiments on an unsteady turbulent boundary layer are reported in which the upstream portion of the flow is steady (in the mean) and in the downstream region, the boundary layer sees a linearly decreasing free stream velocity. This velocity gradient oscillates in time, at frequencies ranging from zero to approximately the bursting frequency. For the small amplitude, the mean velocity and mean turbulence intensity profiles are unaffected by the oscillations. The amplitude of the periodic velocity component, although as much as 70% greater than that in the free stream for very low frequencies, becomes equal to that in the free stream at higher frequencies. At high frequencies, both the boundary layer thickness and the Reynolds stress distribution across the boundary layer become frozen. The behavior at higher amplitude is quite similar. At sufficiently high frequencies, the boundary layer thickness remains frozen at the mean value over the oscillation cycle, even though flow reverses near the wall during a part of the cycle.
Parikh, P. G.↗
Tunnel-to-tunnel correlation
Flow quality is discussed. Incremental comparisons of: (1) the angle of attack, (2) the axial force coefficient, and (3) the base cavity axial force coefficient against the normal force coefficient are presented. Relative blockage determination, relative buoyancy corrections, and boundary layer transition length are discussed. Blockage buoyancy caused by tunnel model wall dynamic interaction is discussed in terms of adaptive walls. The effect of 'transonic turbulence factor' is considered.
Steinle, F. W., Jr.↗