A single unsteady DBD plasma actuator excited by applying two high voltages simultaneously for flow control

Dielectric barrier discharge plasma actuators have attracted a lot of attention to use as new technologies for active flow control. In this paper, an experimental investigation of a single unsteady plasma actuator driven by two simultaneous sinusoidal high voltages is carried out. The aerodynamic performance of this plasma actuator is investigated for flow control of a wind turbine blade. Leading edge separation control at Reynolds number of 0.26 x 10 6 and in a wide range of angles of attack including linear, stall, and post-stall regions is considered as the test case. The momentum imparted by the plasma actuator to flow is investigated via measuring induced electric wind velocity, which represents that the induced velocities in the steady mode, with v max 5 m / s, are higher than that of the unsteady mode. The important aspect of exciting the unsteady dielectric barrier discharge plasma actuator in this new approach is improving its efficiency through increasing the authority of momentum addition to flow and reducing the minimum input power for discharge ignition relative to its typical grounded structure. This can be very important practically in flow control applications where the amount of consumed energy is a substantial factor in determining the actuator's efficiency. The obtained aerodynamic results reveal that the unsteady plasma actuator has the best operation in post-stall angles of attack, which is of great importance for operation characteristics of wind turbine blades. The power spectral density of pressure time series illustrates that the unsteady plasma actuator affects the flow through instabilities of the separation layer and vortex shedding structure.