Electrical and optical characteristics of surface plasma actuator based on a three-electrode geometry excited by nanosecond-pulse and DC sources

Abstract

Plasma actuator based on surface dielectric barrier discharge for active flow control has been widely investigated due to broad application prospects. In order to obtain extensive surface plasma, a plasma actuator based on a three-electrode structure sustained by nanosecond-pulse and DC sources is investigated. In this paper, the correlation between actuator parameters (especially in DC source polarity) and discharge characteristics is presented. The experimental results show that the plasma length is extended up to the third electrode due to a sliding discharge induced by a negative DC voltage. The negative DC voltage has a significant effect on the discharge current and propagation velocity of the slide discharge. Compared to the negative DC voltage, the plasma actuator with a positive DC voltage is difficult to induce a sliding discharge. Moreover, the spectrum characteristics, pressure wave, and vortex characteristics are investigated by means of time-resolved spectrum and schlieren visualization, respectively. The vortex characteristics indicate that the sliding discharge at a negative DC voltage induces two jets in opposite directions. However, the vortex characteristics with a positive DC voltage show that the air flow can be induced closer to the dielectric surface than those with a negative DC voltage. It is because a larger perturbation region in the case of positive DC voltage is beneficial to jet acceleration and thus enhances the flow control capability.