Straight and curved type micro dielectric barrier discharge plasma actuators for active flow control

We develop micro dielectric barrier discharge plasma actuators (DBD-PAs) for active flow control under low external flow conditions. Our micro DBD-PA consists of thin dielectric material and electrodes having a small width and shape variation in the span-wise direction. The fundamental characteristics of the induced flow structures and the effectiveness of the micro DBD-PAs for separated flow over an airfoil are experimentally studied. The flow structures induced by a straight and a curved type micro DBD-PAs in quiescent air are visualized by the tracer method and processed by particle image velocimetry technique. It is found that the curved type DBD-PA produces three-dimensional flow structures as the results of counter flows that impinge each other. For the separation control of the airfoil flow, the angle of attack and free-stream velocities are set to 7.5° and 2 and 3 m/s, respectively. Results present that the separation is successfully suppressed by the use of the curved type micro DBD-PA and the curved type micro DBD-PA shows better capability in comparison with that of the straight type micro DBD-PA due to the induced flow structures.