Unsteady Flow Structures Induced by Single Microsecond-Pulsed Plasma Actuator

The unsteady flowfield around a single microsecond-pulsed dialectic barrier discharge plasma actuator in quiescent air is investigated using particle image velocimetry, Schlieren visualization, and a pressure-field microphone. A single microsecond pulse with a rising time of 75 mu sand a decaying time of 65 mu s is employed. It is the first time that a series of planar-type pressure waves which is induced by the microsecond-pulsed dialectic barrier discharge plasma actuator and propagates outward in the rising period is observed. It is likely that the streamer discharge which occurs in the rising stage and conduces to numerous current pulses with energy release could play an important role in generating these pressure waves. During the plateau of the constant voltage of 10 kV, a wall jet that has a deflection angle of 60 deg is formed, and the maximum velocity is approximately 1.6 m/s, while a new type of arched jet is observed during the plateau of the constant voltage of 0 kV. These wall jets provide favorable conditions for creating some perturbations and promoting mixing between the mainstream flow and the boundary flow.