Observations of hypervelocity boundary-layer instability
نویسندگان
چکیده
منابع مشابه
Observations of hypervelocity boundary-layer instability
A novel optical method is used to measure the high-frequency (up to 3 MHz) density fluctuations that precede transition to turbulence within a laminar boundary layer in a hypervelocity flow. This optical method, focused laser differential interferometry, enables measurements of short-wavelength, high-frequency disturbances that are impossible with conventional instrumentation such as pressure t...
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T HE prediction of laminar–turbulent transition location in highspeed boundary layers is critical to hypersonic vehicle design because of the weight implications of increased skin friction and surface heating rate after transition. Current work in T5 (the California Institute of Technology’s free piston reflected shock tunnel) includes the study of problems relevant to hypervelocity boundary la...
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The curved bow shock in hypersonic flow over a blunt body generates a shear layer with smoothly distributed vorticity. The vorticity magnitude is approximately proportional to the density ratio across the shock, which may be very large in hypervelocity flow, making the shear layer unstable. A computational study of the instability reveals that two distinct nonlinear growth mechanisms occur in s...
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The Richtmyer–Meshkov instability is numerically investigated for strong shocks, i.e., for hypervelocity cases. To model the interaction of the flow with non-equilibrium chemical effects typical of high-enthalpy flows, the Lighthill–Freeman ideal dissociating gas model is employed. Richtmyer’s linear theory and the impulse model are extended to include equilibrium dissociation chemistry. Numeri...
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The influence of high levels of wall cooling on the stability of hypervelocity boundary layers is investigated. Such conditions are relevant to experiments in high-enthalpy impulse facilities, where the wall temperature is much smaller than the free-stream temperature, as well as to some real flight scenarios. Some effects of wall cooling are well known, for instance, the stabilization of the f...
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ژورنال
عنوان ژورنال: Journal of Fluid Mechanics
سال: 2015
ISSN: 0022-1120,1469-7645
DOI: 10.1017/jfm.2015.489