Numerical Investigation on Circumferentially Arranged Combination Plasma Synthetic Jets for Shock-Wave Drag Reduction

As a compact, high-speed, and no-external-source flow control technique, opposing plasma synthetic jets (PSJs) have demonstrated the potential for shock-wave drag reduction. However, under the increasing freestream Mach number and static pressure, the drag reduction of one individually arranged opposing PSJ becomes limited. To address this limitation, this study proposes a set of circumferentially arranged combination PSJs, which can utilize the interactions between one central PSJ and four circumferentially distributed side PSJs to enhance drag reduction performance. Numerical simulations are conducted to investigate the effects of jet mode, discharge interval, and energy ratio on the drag reduction upon a hemisphere at [Formula: see text]. The results show that the proposed combination PSJs can enhance drag reduction by generating extensive low-pressure recirculation zones through flow mixing. Under a total energy input of 45 J, the combination PSJs achieve an average drag reduction of 14.73%. By setting a proper discharge interval ([Formula: see text]), the maximum pressure ratio of the side PSJs can be increased by the covering of the low-pressure recirculation zones. When [Formula: see text], the maximum drag reduction can rise to 43.12%. Additionally, the overall energy efficiency is mainly affected by the side PSJs. Appropriately reducing the side PSJs’ energy input can improve the overall energy efficiency.