Surface dielectric barrier discharge: Effect of encapsulation of the grounded electrode on the electromechanical characteristics of the plasma actuator

Active flow control is a rapidly developing topic because the associated industrial applications are of immense importance, particularly for aeronautics. Among all the flow control actuators, plasma-based devices are very promising. In most cases, the plasma actuator is based on a surface dielectric barrier discharge (DBD) established between two electrodes flush mounted on both sides of a dielectric layer. In this paper, the effects of the encapsulation of the grounded electrode on the electric wind produced by a surface DBD are investigated by Pitot velocity measurements. Moreover, the current versus time is statistically analysed in order to count the number of streamers, their duration and the electrical charge they transfer. Unfortunately it was not possible to detect and separate the glow-type synchronous current because its amplitude is of the same order as noise. On one hand, the encapsulation of the grounded electrode results in an increase of the electromechanical efficiency of the surface DBD plasma actuator because the electrical power consumption is divided by two. On the other hand, statistical analysis of the discharge current versus time has shown that the encapsulation results in a decrease of the streamer number and an increase of the charge transferred by each current streamer because the duration of streamers is longer.