The control mechanism of micro-vortex generators on streamwise vortex-shock train coupling interference

To mitigate the negative impacts of streamwise vortex-shock train coupling interference and enhance the flow field quality, direct-connected wind tunnel experiments were conducted on the concave channel at incoming Mach numbers of 2.10 and 2.85. These experiments investigated the control effects of micro-vortex generators (MVGs) with different heights on the coupled flow field. The results indicate that MVGs control the coupled flow field by generating oblique shocks, expansion waves, and the wake structure. The interaction between oblique shocks and streamwise vortices diminishes the intensity of the streamwise vortices, thereby mitigating the shock deformation resulting from their interaction with the shock train leading shock (STLS). Meanwhile, the oblique shocks and the wake structure jointly inhibit the upstream movement of the STLS, enhancing the backpressure resistance of the coupled flow field. This study finds that the optimal control configuration is MVGs with a height of 2 mm (0.48δ). At an incoming Mach number of 2.10, the expansion waves and the wake structure alter the structure of the STLS, transforming it from the λ-type to the X-type. At a Mach number of 2.85, the oblique shocks and the wake structure mitigate the large amplitude oscillation and rapid movement of the STLS, thereby enhancing the stability of the coupled flow field. The use of MVGs effectively improves the quality of the coupled flow field. Insights into the control mechanisms of coupled flow fields provide valuable information for refining vortex-wave interference and its control mechanisms, as well as for the application of inward-turning inlets.