Study of Shock and Induced Flow Dynamics by Nanosecond Dielectric-Barrier-Discharge Plasma Actuators

The shock wave behavior generated from a single shot of pulsed nanosecond dielectric-barrier-discharge plasma actuator with varying pulse voltages in quiescent air was studied by experiments and numerical simulations. The experiments included using the schlieren technique, a fast response pressure transducer, and a two-velocity-component particle image velocimetry system to measure the propagation of the shock wave, the shock overpressure, and the shock induced flow, respectively. For the numerical simulation, a simple “phenomenological approach” was employed by modeling the plasma region over the encapsulated electrode as a jump-heated and pressurized gas layer. The present investigation revealed that the behaviors of the shock wave generated by the nanosecond pulsed plasma were fundamentally a microblast wave, and their speed and strength were found to increase with higher input voltages. The blast wave occured about 1 to after the discharge of the nanosecond pulse, which was dependent on the input voltages, and then it decayed quickly from a speed of around to a speed of around within about (2–3 mm from the actuator surface). The shock-induced burst perturbations (overpressure and induced velocity) were found to be restricted to a very narrow region (about 1 mm) behind the shock front and lasted only for a few microseconds. In a relatively long time period after the discharge of the plasma, a fairly weak induced vortex structure was observed. These results indicated that the pulsed nanosecond dielectric-barrier-discharge plasma actuator had stronger local effects in time and spatial domain.