Control of the Flow Direction Induced by Plasma Actuator

It is known that a dielectric barrier discharge plasma actuator (DBD-PA) induces tangential flow in the vicinity of the wall. In the conventional studies the induced flow was generated in the direction from the upper electrode to the lower electrode. The direction of the induced flow was one-way using DBD-PA composed of asymmetric electrodes. However, in this experiment, it was found that the flow induced by DBD-PA can be generated in the opposite direction in contrast with conventional results. In this study, effects of DBD induced flow on applied voltage characteristics were investigated by means of PIV analysis. When square wave voltages biased negative are applied to the electrodes of DBD-PA, the flow is generated in the direction from the lower electrode to the upper electrode. It should be noted that it is not reversed by sine waves even with same amplitudes and frequencies when the reverse flow was generated by DBD-PA, a vortex is induced above the area of plasma. The vortex height was about 10 mm, and it tended to change slightly its shape based on the electrode width. It seems that the vortex on the plasma area play an important role in the mechanism of the reverse flow. The plasma actuator has been focused as an actuator for aerodynamic flow control. If it becomes possible to control the flow direction as well as the velocity by changing the applied voltage, the applications of the plasma actuator can be spread across a wide area of industry.