Effectiveness of millisecond pulse discharge on hypersonic oblique shock wave

Abstract

The characteristics of millisecond pulse discharge in quiescent air and its effects on a Mach 6 hypersonic oblique shock over a ramp have been experimentally investigated with high-speed schlieren imaging and surface pressure measurement. The discharge between three pairs of electrodes was aligned in the direction of the airflow with pulse widths extending to a few milliseconds. The evolutionary characteristics of the energy deposition induced by the discharge pulses in quiescent air reveals that the discharge generating a significant thermal disturbance and lasting long enough may have greater control authority on hypersonic shock manipulation. In hypersonic flow, the plasma layer generated by the discharge propagates downstream and accumulates at a high penetration depth. Dilution of the ramp-induced ramp shock wave is observed under the disturbance of the plasma layer at a frequency of 100 Hz. Under repetitive pulse discharge, shock wave attenuation was demonstrated by pressure decreasing along the compression surface at the region where the plasma layer covers. The law of transient pressure distribution is acquired with the aid of the p–θ polar curve in shock wave analysis. The modification of pressure distribution indicates that the aerodynamic force of a compression surface can be controlled by deploying the control strategy.