Numerical Simulations Exploring Dielectric Barrier Discharge-Induced Steady and Pulsed Suction

Abstract

This exploratory numerical study investigates the use of dielectric barrier discharge (DBD) plasma actuators to drive flow in a channel and in various slots for potential active flow control (AFC) applications. The approach of mounting the DBD actuators inside of channels and slots to generate flow is explored as an option to the traditional approach of mounting the actuators directly to the surface exposed to the free stream. The numerical simulations employ a well-validated high-fidelity Navier-Stokes flow solver augmented with a phenomenological model that represents the plasma-induced time-average body force imparted by each actuator on the fluid. Parametric studies are performed for three twodimensional shapes: a channel in quiescent flow, flow over a flat plate with a suction slot, and a flat plate with a c-shaped slot that removes and injects fluid into the flow. Threedimensional computations were also performed for these cases. For the case of channel flow the effects of Reynolds number, magnitude and height of the body force, and addition of multiple actuators were explored. In all cases wall jets develop near the actuators at the top and bottom of the channel that lift from the walls downstream of the actuators and merge to form a parabolic profiles. For the flat plate with steady suction slot, the magnitude of the body force required to effectively remove slow momentum flow from the flat-plate boundary layer was determined. If the actuator strength is not large enough, the slot was unable to develop suction and instead increased the injected mass into the flow. The c-slot case demonstrated the ability to trip the boundary layer downstream of the slot using both steady and pulsed actuators.