Investigation on the shockwave induced by surface arc plasma in quiescent air

Abstract

The shockwave induced by surface direct-current (DC) arc discharge is investigated both experimentally and numerically. In the experiment, the shockwave generated by rapid gas heating is clearly observed from Schlieren images. The peak velocity of the shockwave is measured to be over 410 m/s; during its upright movement, it gradually falls to about 340 m/s; no remarkable difference is seen after changing the discharge voltage and the pulse frequency. In the modeling of the arc plasma, the arc domain is not simulated as a boundary condition with fixed temperature or pressure, but a source term with a time-varying input power density, which could better reflect the influence of the heating process. It is found that with a reference power density of 2.8×1012 W/m3, the calculated peak velocity is higher than the measured one, but they quickly (in 30 μs) become agreed with each other. The peak velocity also rises while increasing the power density, the maximum velocity acquired in the simulation is over 468 m/s, which is expected to be effective for high speed flow control.