Flow Separation Control on 2-D Bluff Body Using Dielectric Barrier Discharge Plasma Actuators

초록

Active flow control can provide more versatile control methods to reduce an aerodynamic drag compared to a passive flow control such as an aerodynamic shape improvement. There are various active flow control techniques including synthetic-jet actuators, piezoelectric actuators, pulsed micro-jets, and vortex generator jets. These actuating devices are based on mechanical motions to influence the fluid. In the present study, DBD (Dielectric Barrier Discharge) plasma actuator was used to control the flow separation. The DBD actuator has a simple structure, in which neither components for mass injection nor mechanical moving parts is required. Furthermore, the DBD actuator is easy to be installed on smooth surfaces and transformed into different shapes. In the present study, the DBD actuators were designed as a form of a thin film and installed on a two-dimensional bluff body. The DBD actuators were installed in the front and rear incline planes, respectively. Wind-tunnel tests were performed to measure a drag reduction by controlling the flow separation using the DBD actuators. Flow visualization using a smoke was used to verify the possibility of the flow separation control using the DBD actuator. The flow stream lines were observed when the plasma discharge was applied as varying the discharge voltage. At the zero wind velocity, where the flow separation was not occurred, the drag was not changed because the effect of the electric wind generated by the DBD actuator on the drag measurement was negligible. At the wind velocity of 2 m/s, the drag was reduced by 9.7%, whereas the drag reduction decreased as the wind velocity increased.