Effect of Spanwise Dynamic Micro-Vortex Generators on Hypersonic Shock Wave/Turbulent Boundary Layer Interaction

The shock wave/boundary layer interaction (SWBLI) is a common flow phenomenon in high-speed aircraft flow fields. It is important to control the separation caused by SWBLI. This paper investigates the influence of spanwise periodic-motion micro-vortex generators (MVGs) on SWBLI. A combination of particle image velocimetry (PIV), high-frequency Schlieren and fluorescent oil-film visualization was employed to analyze the interaction region of a flat plate compression ramp model. The incoming flow Mach number was 6, and the MVGs oscillation frequencies were 10 Hz, 30 Hz and 50 Hz, respectively. The results reveal that neither the presence nor the spanwise oscillation in the MVGs fundamentally altered the separation–reattachment flow structure. Nonetheless, both factors contributed to an increase in boundary layer thickness and an expansion of the absolute size of the separation region. The trailing vortices generated by the MVGs exerted a stabilizing influence on near-wall turbulent structures, resulting in a reduction in surface friction drag. However, the drag reduction effect diminished as the oscillation frequency increased, corresponding to a weakening of the trailing vortex strength. Additionally, the MVGs and their spanwise oscillation modulated the low-frequency energy distribution of the flow, amplifying the low-frequency oscillation peak associated with the separation shock and raising the time-averaged oscillation position.