Compression ramp shock wave/boundary layer interaction control with high-frequency streamwise pulsed spark discharge array

A streamwise array of pulsed spark discharge operating at a high frequency of 10 kHz is used to control the shock wave/boundary layer interaction (SWBLI) induced by a 24 degrees compression ramp (CR) in a Mach 2.0 flow. High-speed schlieren imaging at 50 000 frames/s is deployed for flow visualization. The schlieren snapshots, as well as statistics of the schlieren sequence, show that the intensity weakening effect on the shock wave can be achieved for a long time up to 20 ms, which is the first experimental demonstration of stable control on the CR-SWBLI with plasma actuators. Then, based on fast Fourier transform analyses, the low-frequency unsteadiness of the shock wave is also significantly modified and the dominant oscillation frequency is switched to the high frequency St = 0.32. The mechanism of the encouraging control outcome is finally discussed that the strong separation wave induced by a CR is replaced by a multistage weak compression wave produced through a high-frequency actuator array.