Study of Oblique Shock Wave Control by Surface Arc Discharge Plasma

Abstract

The mechanism of oblique shock wave control by surface arc discharge plasma is explored through a combined numerical and experimental study. The experiments are conducted in a supersonic wind tunnel with Mach number of 2.5, total pressure of 3.5–6.4 bar, and total temperature of 300 K. An oblique shock is formed by a compression ramp with an angle of 7 deg mounted on the lower wall of the wind tunnel. Six electrodes are arranged equally in the spanwise direction and upstream of the compression ramp. The schlieren images show that the angle of the original oblique shock is increased, and the surface pressure measurements indicate that the oblique shock is weakened by the addition of the stable discharge arc. The reason is that the arc heating decreases the Mach number upstream of the oblique shock; thus, the oblique shock is weakened and the shock angle is increased. A three-dimensional numerical simulation is performed using experimental configuration. Results show that the static pressure increases in front of the oblique shock and decreases after the shock, which is in good agreement with the experimental measurements. This validates that the numerical model presents a reasonable approach for the arc discharge plasma and further confirms the predominant role of the thermal effects of plasma on shock manipulation.