The current study investigates the control effect of the pulsed arc discharge plasma (PADP) on the impinging shock wave and boundary layer interaction (SWBLI) generated by a 14{degree sign} wedge in a Mach 2.5 flow. The response characteristics of SWBLI on pulsed arc discharge (PAD) actuation were illustrated, and the controlling mechanism of shock-induced flow separation under different plasma power settings was revealed. The results showed that when setting the exciting power density ph as 1.0×1011 W/m3, the oblique shock wave obtained an obvious fluctuation, and the foot of the reattachment shock wave was partially removed. In addition, as the controlling gas bubble (CGB) passed through the interaction region, the reverse flow zone was enlarged, and the separation shock wave was shifted upward. When ph was set to 4.8 × 109 W/m3, the flow separation induced by SWBLI was effectively suppressed and the size of the reverse flow zone was significantly reduced. Moreover, as the energy input was increased, the arc-induced blast wave (BW) velocity was obviously enhanced. Additionally, it is further found that the arc plasma energy deposition (APED) density in discharge region was the determining factor for SWBLI control, even for a relatively small exciting energy input. Better drag reduction of the flow field would be achieved with PADP of higher power density, and a drag reduction rate of nearly 10.05 % was obtained at ph = 1 × 1011 W/m3 control condition.

Experiments and numerical simulations of shock wave/turbulent boundary layer interaction (STBLI) disturbed by arc plasma energy deposition (APED) were carried out in this paper. The experiments were conducted in a M = 2.497 wind tunnel. Both the flow structures and the evolution process of impinging STBLI disturbed by APED were captured by time-resolved schlieren imaging. The disturbance effects of APED on supersonic flow without STBLI were studied with different capacitor stored energies. Furthermore, under the same capacitor stored energy, the impinging STBLI control with APED were explored in different flow deflection angles. The experimental results indicated that thermal bubbles induced by APED had a high penetration depth and impacted the STBLI seriously. Compared to the incident shock wave, the separation shock wave was more sensitive to the influence of APED and showed significant instability. With equivalent energy deposited into the flow, the ability of APED to disturb the impinging STBLI was decreased as the flow deflection angle increased, and the separation shock wave had a smaller position change and shorter recovery time. The direct numerical simulation results showed that the APED added in a flow field can hinder the velocity development of the turbulent boundary layer. The unsteadiness of separation shock waves was induced by both thermal bubbles and blast waves, and the thermal bubbles' effects were dominant. They would modify the compressibility of the boundary layer and enlarge the separation zone, which contributed to the separation shock wave's dispersion and movement.

This paper studies the response characteristics of shock wave and boundary layer interaction (SWBLI) controlled by high-frequency pulsed arc discharge (PAD) in a Mach 2.5 flow. The dynamic evolution of SWBLI disturbed by arc plasma energy deposition was captured, and the controlling mechanism under different exciting power and frequency was explored. The results showed that the blast wave induced by PADs had a strong impact on SWBLI structures and distorted the separation shock wave. During the downstream propagation, the controlling gas bubbles (CGBs) delivered a continuous thermal excitation to the boundary layer and reached the maximum penetration depth near the semi-cylinder. The arc discharge in the SWBLI region induced larger energy deposition, which made the heating zone obtain the highest initial temperature and longest heating duration. Under the plasma condition of 1 × 1011 W/m3/15 kHz, both the upstream part of the shear layer and the foot portion of the reattachment shock wave were removed. When setting the excitation to 2.5 × 1010 W/m3/60 kHz, a thermal exciting surface of merged CGBs was formed and the separation shock wave was completely replaced by an equivalent compression-wave system. A better drag-reduction effect on the flow field would be produced by the actuator with an increased operating power or frequency, and a drag reduction rate of nearly 25.5% was achieved under the 2.5 × 1010 W/m3/60 kHz control condition.