Momentum transfer and flow induction in a dielectric barrier discharge plasma actuator

The flow induction process resulting from a dielectric barrier discharge plasma actuator was experimentally investigated by a flow visualization method. This method enables a detailed examination of the flow induction process. The overall behavior as well as the detailed temporal and spatial behavior of the flow induction process was clarified. The induced flow originated from the vicinity of an exposed electrode edge, and similar to a wall jet, it smoothly spread over the surface until a vortex was generated at the tip of the wall jet. Even after the vortex disappeared, the wall jet continued to extend. This wall jet was classified into two distinct regions. The first region contained the wall jet extending from the electrode edge to the location where the vortex was generated. In this region, active momentum coupling occurred; therefore, the flow was actively induced. During active momentum transfer in the acceleration region, the periodic inflation of the wall jet thickness was synchronized with the decreasing phase of the applied high-voltage input, which suggested different mechanisms of momentum transfer during the increasing and decreasing phases of the high-voltage input. The second region was an extension of the first one and was formed through the inertia of the flow originating from the first region.