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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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Electron density irregularities convected past space probe relationship to radio intensity power spectrum scintillations
Subsonic wind tunnel investigation of rotary wing configurations for VTOL aircraft in cruise mode
Autocorrelation functions for diffuse cosmic X rays
Determining deployment characteristics of all-flexible parawings by free flight tests
System of regional agricultural land use mapping tested against Apollo 9 color infrared photography of Imperial Valley, Calif.
Elastic-plastic finite element analysis of near crack tip stress and strain field structure
Noise data were obtained with a model of an externally blown flap of the type that is currently being considered for STOL aircraft. The noise caused by impingement of the jet on the flap is much louder than the nozzle jet noise. It is especially so directly below the wing. The noise level increases as the jet velocity and flap angle are increased. The sound power level increased with the sixth power of velocity. Several physical variations to the STOL model configuration were also tested. Two such variations, a large board and a slotless curved plate wing, had the same power spectra density (Strouhal number curve) as the model.
There are no author-identified significant results in this report.
Observation of fringes from 31 compact radio sources, including eight known or suspected galaxies and 20 known or suspected QSSs, by using the Goldstack interferometer at lambda = 3.8 cm (d/lambda = 10 to the 8th power). Fringe visibility curves were obtained for nine sources showing structure on a scale of .001 sec of arc, and simple models are fitted to the data. Results for 3C 273 and 3C 279 are compared with data taken by Knight et al. (1971) at an earlier epoch. The apparent changes in brightness distribution of 3C 273 and 3C 279 are difficult to explain.
Rawinsonde wind profile data provide adequate wind shear information for vertical height intervals greater than 1 km. To specify wind shears for intervals below 1 km for space vehicle design, detailed wind-profile information like that provided by the FPS-16 Radar/Jimsphere system or an extrapolation procedure is required. This paper is concerned with the latter alternative. It is assumed that any realization from an ensemble of wind profiles can be represented in terms of a Fourier integral. This permits the calculation of the ensemble standard deviation and mean of the corresponding shear ensemble for any altitude and shear interval in terms of the power spectrum of the ensemble of wind profiles. The results of these calculations show that the mean and standard deviation of the wind shear ensemble, as well as the wind shear for any percentile, asymptotically behave like the vertical interval to the 0.7 power. This result is in excellent agreement with shear data from Cape Kennedy, Fla.
To assess the possibility of achieving extensive laminar flow on conical vehicles during hyperbolic entry, the Ames Research Center has had an ongoing program to study boundary-layer transition on ablating cones. Boundary layer transition results are presented from ballistic range experiments with models that ablated at dimensionless mass transfer rates comparable to those expected for full scale flight at speeds up to 17 km/sec. It was found possible to measure the surface recession and hence more accurately identify regions of laminar, transitional, and turbulent flow along generators of the recovered cones. Some preliminary results using this technique are presented.
Surface features on the flanks of Martian shield volcanoes photographed by Mariner 9 are identified as lava flow channels, rift zones, and partly collapsed lava tubes by comparisons with similar structures on the flanks of Mauna Loa shield volcano, Hawaii. From these identifications, the composition of the Martian lava flows is interpreted to be basaltic, with viscosities ranging from those of fluid pahoehoe to more viscous aa.
The noise generated by a 2.26- by 11.43-cm slot nozzle with a V-gutter reverser, as well as some aerodynamic data on flow, thrust-reversal efficiency, and nozzle jet velocity decay were studied. The experimental data are scaled up to sizes suitable for reversing the wing flow of a 45/400-kg augmentor-wing-type STOL airplane, yielding perceived noise levels well above the 95-PNdb design goal on the 152-m sideline. The reverser, in addition to being noisier than the nozzle alone, also had a more uniform directional distribution and more high frequency noise. The maximum overall sound pressure level and the effective sound power level both varied with the sixth power of nozzle jet velocity. Preliminary experiments indicated possible sideline noise reduction by shielding.
There are no author-identified significant results in this report.
There are no author-identified significant results in this report.
There are no author-identified significant results in this report.
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