Flow Control on a Bluff Body Using Dielectric Barrier Discharge Plasma Actuators

Abstract

In this study, a traditional dielectric barrier discharge (DBD) plasma actuator and plasma streamwise vortex generators (PSVGs) are installed on a bluff body to control the wake fluctuations. Experiments are conducted in a wind tunnel with a chord Reynolds number of 5000. Particle image velocimetry and hot-wire measurements are used to obtain the details of the flowfields. The results show that both DBD and PSVG actuations clearly reduce the size of the recirculation bubble regions, and they significantly suppress the wake fluctuations. A comparison of the traditional DBD and PSVG cases shows that PSVGs have better control performance on the reduction of the recirculation bubble sizes and the Karman vortex shedding frequency in the wake at low speed. Specifically, the PSVGs have a strong three-dimensional effect on the entire flowfield and generate streamwise vorticities that interact with the shear flow over the bluff body. The local flow separations are thereby suppressed considerably. The induced streamwise vorticities are further entrained downstream by the ambient freestream, which consequently reduces the recirculation bubble behind the bluff body and suppresses the wake fluctuations. These results suggest that PSVGs are promising devices for conducting flow control in bluff body wakes at low speed.