Jet flow control by synchronous drive of two DBD-PAs in nozzle and on bluff body

Abstract

In this study, two dielectric barrier discharge plasma actuators (DBD-PAs) are driven at different times to control a circular jet flow. DBD-PA was installed inside a nozzle and on a disk-shaped bluff body above the nozzle. A vortex was generated in the jet using DBD-PA in the nozzle, and the development of the vortex was controlled using the DBD-PA installed in the disk-shaped bluff body above the nozzle. The two DBD-PAs were driven with a time lag based on the time the vortex reached the bluff body. The findings reveal that the vortices did not pair with each other when the DBD-PA of the bluff body was slightly delayed from the timing of the occurrence of the vortex on the circulating flow side. When the vortices did not pair, the flow was not entrained in the circulating flow, causing the jet width to widen. The vortices paired with each other when the DBD-PA of the bluff body was driven at the same time as or long after the occurrence of the vortex on the circulating flow side. When the vortex pair with each other, they collapse quickly after pairing, and the jet width narrows, as the flow is entrained in the circulating flow. The difference in jet width downstream of the bluff body was found by driving the two DBD-PAs installed inside the nozzle and on the bluff body at different times.