Physical Mechanism of Tri-Electrode Plasma Actuator with Direct-Current High Voltage

Abstract

Tri-electrode plasma actuator (TED-PA), which has a third electrode with DC high voltage, can generate stronger jet than that of conventional two-electrode plasma actuator. However, the behavior of the jet in TED-PA is totally different from that in a conventional plasma actuator; the induced jet is deflected upward. To clarify the jet deflection mechanism and performance improvement mechanism of TED-PA, the discharge plasma and flow field are numerically simulated. The results show that the jet deflection appears in both cases of negative and positive DC voltage; a rightward jet from the AC electrode and a leftward jet from the DC electrode are generated, and the collision of the two jets generates the upward jet. The jet becomes stronger by the DC high voltage due to two factors: negative body force generation around the DC electrode and positive body force enhancement around the AC electrode. The negative body force generation results from the drift motion of the positive ions in the positive DC voltage case, and, on the other hand, that of the negative ions in the negative DC voltage case. The positive force enhancement is due to the electric field intensification by the DC voltage.