Stability, Transition and Turbulence in Mixing Layers and Adjacent Streams.
Interim progress rept. 1 Oct 77-30 Sep 78,
FORD AEROSPACE AND COMMUNICATIONS CORP NEWPORT BEACH CALIF AERONUTRONIC DIV
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This report describes accomplishments in basic research dealing with phenomena in parallel viscous flows. An experiment has been completed on the development of the mean flow in wakes shed by nozzle arrays typical of gas-dynamic lasers. In this experiment, the wake velocity, temperature and density was mapped in wakes generated at Mach 4 in the Companys Supersonic Wind Tunnel. The results are in general agreement with theoretical predictions developed under an earlier OSR study in which theoretical rules on wake flows were set up for laser cavity design. A second problem addressed dealt with a novel approach to predicting transition in parallel shear flows. The basic physics in this approach consists of the postulate of a universal turbulence Reynolds number, below which self-preserving turbulence is impossible. Finally, the data analysis was completed on an earlier hypersonic boundary layer stability experiment done at AEDC. The data show little change of the stability diagram with heat transfer although the amplification rates were substantially increased when the wall temperature was lowered. The present results were disseminated through two technical reports, three journal articles, three delivered papers and by personal contact with Air Force engineering centers.
- Fluid Mechanics