Correlation of Incoming Boundary Layer Pitot Pressure Fluctuations with the Unsteadiness of Fin-Induced Shock Wave Turbulent Boundary Layer Interactions
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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This study focuses on the effects of boundary layer pitot pressure fluctuations on fin-induced separation shock unsteadiness. Experiments performed in two phases under adiabatic wall conditions in a Mach 5 wind tunnel used high frequency-response transducers to measure fluctuating pressures in a turbulent boundary layer and a separated flow induced by a hemi-cylindrical unswept fin. Phase I results indicate that the turbulent boundary layerfreestream interface pitot pressure fluctuation frequency levels do not correlate with the sharp fin- induced shock wave turbulent boundary layer interaction aperiodic separation shock motion frequencies. In Phase 2, correlations between fluctuations in incoming boundary layer pitot pressures, intermittent region wall pressures, separation shock dynamics, and fin leading edge pressures show contributions from fluctuations at both low frequencies approximately 500 Hz - their source is not well understood - and high frequencies, driven by incoming turbulence.