Experimental Investigation of the Effect of Steady and Unsteady Actuation on Performance of Plasma Actuators for Active Flow Control in Boundary Layer

DBD plasma actuators are devices for active flow control, which recently have been widely of interest for aerodynamicists. Due to their advantages, there is a great focus on plasma actuators with the ability of unsteady actuation. In this paper, using a plasma power supply with the ability of unsteady actuation, the effective parameters on the performance of DBD plasma actuators in two conditions, i.e. steady and unsteady actuations, was experimentally measured and compared. In this regard, the effects of the applied voltage, carrier frequency, excitation frequency and duty cycle on the induced velocity, electric current and power consumption of the actuator was investigated. For the steady actuation, it was revealed that an increase in the applied voltage and carrier frequency leads to firstly an increase in the induced flow velocity, but afterwards, when streaky glow discharge regime starts (non-uniform plasma formation), induced velocity decreases. On the other hand, it wasfound that for the unsteady actuation, the variation of the excitation frequency does not significantly affect the electrical current and the induced velocity, but these values increase almost linearly with increasing the duty cycle. Generally, it was observed that using the unsteady actuation in comparison to the steady one, can cause considerable reduction in the electrical power consumption and also can have a better performance in the induced flow control.