Study on continuous vortices induced by sub-microsecond pulsed surface dielectric barrier discharge plasma

Abstract

The experiments to generate vortices continuously using sub-microsecond pulsed surface dielectric barrier discharge (SDBD) actuator are conducted by particle image velocimetry (PIV). The double-frequencies actuation mode is presented which includes repetitive pulse frequency and vortex frequency. It is found that the empty zone of PIV particles appears in the place where the particles are quite few even nil during the experiments. When discharges occur the primary empty zone is produced by the micro explosion due to the released heat of plasma, and when discharges end the secondary empty zone appears. The induced flow is farther apart form wall and the influence of wall friction should be suppressed due to primary empty zone. When the secondary empty zone on the left side of actuator exposed electrode is blown away completely, the next actuation can start. In order to control the flow more effectively, the pulse voltage with higher repetitive frequency should be applied. The pulse number during one vortex time should be more than 10. As the pulse number increases, the maximal velocity of induced flow increases but the momentum transfer efficiency decreases. The mechanisms releasing heat and body force can be triggered by using the sub-microsecond pulse SDBD actuator.