Wave packets generated by a surface glow discharge on a cone at Mach 4
Abstract
A glow-discharge device was developed for studying laminar-turbulent boundary-layer transition in supersonic or hypersonic flows. An experimental study of wave-packet development on a sharp-nosed, 5-deg. half-angle, right-circular cone was conducted in the Mach-4, Purdue Quiet-Flow Ludwieg Tube. Mean-flow and mode-shape profiles were obtained with the cone at zero and 3-deg. angle of attack, along the leeward ray, with a constant-temperature anemometer and a single-element hot-wire probe. Controlled, repeatable, and localized flow disturbances were created by a pulsed, point-source glow discharge on the surface of the cone. Repeatability of the resulting wave packets was 4.5 percent based on peak rms amplitudes. The mean-flow mass-flux profiles were inflectional, and exhibited self-similarity. However, with the cone at 3-deg. angle-of-attack, crossflow resulted in a much thicker boundary layer and a more inflectional mean profile. Mode shapes show that the wave packets reside near the outer edge of the boundary layer, and the peak rms wave-packet amplitude occurs near the inflection point of the mean-flow profile. Although the maximum cone Reynolds number was only about 520,000, weak but significant wave growth was observed.
Degree
Ph.D.
Advisors
Schneider, Purdue University.
Subject Area
Aerospace materials|Fluid dynamics|Gases
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