Effect of the streamwise pulsed arc discharge array on shock wave/boundary layer interaction control

Abstract

The streamwise pulsed arc discharge array (S-PADA), in which five actuators are connected in series with adjustable frequency, is employed to control the shock wave/boundary layer interaction (SWBLI) at a 24° compression ramp in a M = 2.0 flow and under two Reynolds numbers based on boundary layer thickness (Re1 = 46 800 and Re2 = 11 700). High-speed schlieren imaging at 50 000 fps is used for flow visualization. The schlieren snapshots, as well as the statistics of the image sequence, namely, mean and root-mean-square, are examined to reveal the control outcome. The results show that the separated wave foot gradually presents bifurcation and partial disappearance under Re1 with the increasing pulse number of the S-PADA, indicating the decline in the shock intensity. The increase in frequency does affect the control outcome remarkably because shock weakening effect can be achieved under Re1 through 10 kHz and 20 kHz actuations, while no obvious change can be observed by the 5 kHz actuation. The experiments under Re2, where little control effect is exerted by the same methods, are also discussed. It is believed that the separated wave under a lower Reynolds number of Re2 presents the poorly developed turbulent boundary layer; hence, the effective SWBLI control is difficult to be ensured.