REDUCTION OF FLUCTUATING PRESSURE LOADS IN SHOCK BOUNDARY-LAYER INTERACTIONS USING VORTEX GENERATORS

Fluctuating wall pressure measurements have been made in a separated shock wave/turbulent boundary-layer interaction produced by an unswept compression corner in a Mach 5 flow, Wheeler doublet vortex generators were placed upstream of the corner to study their effect on the fluctuating pressure loads within the interaction, The vortex generators produce significant three dimensionality in an otherwise two-dimensional interaction, They reduce the upstream influence and the length of the region of separation shock motion by 60% and 64%, respectively, and they decrease the maximum wall pressure rms near separation by 23% and shift the fluctuations to higher frequencies. The maximum fraction of energy in the resonant frequency band of typical skin panels (i.e,, 100-500 Hz) is decreased by 11%, On the corner face, where the maximum loads occur, the maximum wall pressure rms is reduced by 10%, and the maximum fraction of energy in the 100-500 Hz band is reduced by 35%, These changes are due to a fuller boundary-layer profile, a weaker separation shock, increased boundary-layer turbulence causing increased separation shock jitter, and a shorter region of shock motion.