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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 1,675 records · Page 93
All sourcesNASA NTRSDOE OSTI
NASA NTRS1957

Determination of Vortex Paths by Series Expansion Technique with Application to Cruciform Wings

A series method of determining two-dimensional vortex paths is considered and applied to the computation of vortex positions behind a slender equal-span cruciform wing at any angle of bank as a function of the distance behind the trailing edge. Calculated paths are shown for four bank angles. For a bank angle of 45 degrees comparison is made with the results of a closed expression given in NACA-TN-2605. For other bank angles water-tank experiments provide qualitative comparison. Satisfactory agreement is found for a sufficient distance downstream to include most practical missile-tail positions. The interference forces on an equal-span cruciform wing are calculated for five angles of bank (including the trivial case of zero bank) from the vortex positions found by use of the series.

Alksne, Alberta Y↗
NASA NTRS1936

Turbulent Jet Expansion

This report was made to study the velocity distribution in an open, in a partially open, and in a partially expanding jet. The open-jet observations reveal minor systematic discrepancies from Tollmien's theoretical velocity distribution. The shearing-stress distribution for the partially open jet was determined. The value derived for the ratio of mixing distance to jet width was found to be in close agreement with the corresponding value for the open-jet boundary. The streamline pattern in a partially expanding channel was obtained from the observed velocity distribution and plotted, after which the distribution of the mixing distance for this case was also ascertained.

FORTHMANN E↗
NASA NTRS1991

GIS, GPS, political history, and geo-demography of the Aramamisi Yanomamo expansion

This year a joint US-Venezuelan research project was initiated to locate, identify, and begin long term research on the ecology of the Siapa Basin and the cultural adaptations of Yanomamo communities to this habit, a poorly mapped region of southern Venezuela. During two separate field trips, representing over 500 hours of flying time, local informants were asked to guide a helicopter to villages and other areas of anthropological interest. The location of each place was established with a GPS instrument. Both the Trimble Navigation TransPak and Magellan Nav 1000 Pro were used on these trips. A brief summary of the results and preliminary comparisons of both instruments will be presented.

Chagnon, Napoleon A.↗
NASA NTRS1995

Nonequilibrium Flow Expansion Experiment Around a Blunted Cone

Eleven tests were carried out in DLR's high enthalpy tunnel in Goettingen (HEG), Germany, for reservoir conditions ranging from 10 to 23 MJ/kg and a free stream Mach number of approximately 10. A blunted cone model with a cylindrical afterbody (sting) was investigated. To obtain information on the influence of defined parameters on the body back flow, especially of the reacting gas, the heat transfer rate along the body contour was measured with fast response surface thermocouples on the forebody and sensitive thin film heat transfer gauges on the base and sting of the model. Flow visualization with a holographic interferometry system was provided. Tests are described, and a preliminary interpretation of the observed flow effects are given.

Kastell, Dirk↗
NASA NTRS1995

Plasma expansion layer in the Venus inner ionosheath

We present plasma, magnetic field, and electric field data of the Pioneer Venus Orbiter (PVO) showing that the shocked solar wind in the Venus inner ionosheath exhibits flow conditions substantially different from those in the outer ionosheath. In particular, the plasma density is seen to drop significantly to low values within a layer adjacent to, and downstream from, the planet's ionopause. This change is not seen to develop gradually as the PVO moves into that region of space but occurs abruptly across a well-defined transition which extends downstream along the flanks of the Venus ionosheath. We explore the implications that these observations have in regard to the character of the interaction process between the shocked solar wind and the ionospheric plasma. It is argued that the existence of a sharply bounded region in the inner ionosheath within which the plasma density is severely depressed is consistent with the existence of friction at and near the ionopause. Plasma perturbations generated at this latter boundary, and distributed downstream through the ionosheath flow, may be responsible for the change of properties exhibited by the solar wind plasma in the inner ionosheath.

Perez-De-tejada, H.↗