Induced Flow and Optical Emission Generated by a Pulsed 13.56 MHz–5 kHz Plasma Actuator

A dual-frequency driven plasma actuator is studied with respect to the influence of changing the position of radio frequency 13.56 MHz pulses within the phase of a low-frequency (LF) 5 kHz sinusoidal voltage. Fast imaging and 2-D particle image velocimetry are used to study the optical emission from the discharge and the generation of an induced flow, which can be useful for aerodynamic flow control, in ambient air. The results show that the propagation of the discharge away from the powered electrode and the velocity of the induced flow are maximized when the pulses are positioned at the peaks of the LF waveform. In contrast, the most intense optical emission is found to occur when the pulses are positioned close to the zero crossings for positive LF waveform voltages. The reasons behind these observations are discussed.