Streamer evolution in nanosecond pulsed sliding surface dielectric barrier discharge: 2D numerical modelling

The sliding surface dielectric barrier discharge (SDBD) plasma actuator enables a large interaction region between the discharge and the incoming flow, facilitating active flow control. A 2D model of the sliding discharge, initiated within a three-electrode configuration, is developed. The high-voltage (HV) electrode is connected to a positive nanosecond pulse with an amplitude of 7 kV, and a positive/negative DC voltage is applied to the third electrode, with a 10 mm inter-electrode gap. To account for the dielectric surface charging process, the DC voltage discharge is simulated for a sufficient duration to reach a steady state before the initiation of the nanosecond pulse. This study aims to understand the discharge characteristics of sliding SDBD and to investigate the effects of different polarities and amplitudes of the DC voltage on surface charge distribution, surface ionization wave propagation, electric field evolution, and hydrodynamic perturbations. With the application of negative DC voltage, the deposited surface charge on the dielectric surface neutralizes positive charges at the streamer head, enhancing the electric field at the discharge front, which extends the plasma length up to the third electrode. In contrast, a positive DC voltage impedes net charge transfer, thereby inhibiting the formation of a sliding discharge.