Structure and Dynamics of Bleed-Controlled Impinging Shock/Turbulent-Boundary-Layer Interactions
Porous boundary-layer bleed is often employed to alleviate the detrimental effects of shock/turbulent-boundary-layer interactions (STBLI) in high-speed vehicles. However, outstanding questions remain on the underlying mechanisms through which bleed influences STBLI dynamics. This work addresses this knowledge gap by performing a scale-resolved Large-Eddy Simulation of an impinging STBLI controlled by discrete bleed holes. The simulation has a freestream Mach number of 2.5, an oblique shock generator angle of 8 degrees, and a Reynolds number based on the incoming momentum thickness of 2800. Bleed substantially reduces the separation size and upstream influence of the STBLI compared to the canonical, uncontrolled case. Consequently, the characteristic, low-frequency motion of STBLI-induced separation is mitigated, as revealed by wall-pressure spectra. Energy is shifted from the low frequency separation behavior to a higher-frequency signature caused by the bleed shocks and expansions. The scale-resolved simulations also reveal that these small, localized structures severely limit the turbulence production traditionally seen in the uncontrolled interaction.