Numerical Investigation of Plasma-Based Control for Low-Reynolds-Number Airfoil Flows

Large-eddy simulations are carried out to investigate the use of plasma-based actuation for the control of flows over a finite span wing at low Reynolds numbers. The wing section corresponds to the SD7003 airfoil, which is representative of those employed for micro air vehicle applications. Dielectric-barrier-discharge plasma actuators are used to modify the transitional flow and improve aerodynamic performance. Solutions are obtained to the Navier-Stokes equations, which were augmented by source terms used to represent plasma-induced body forces imparted by the actuators on the fluid. Simple phenomenological models provided the body forces generated by the electric field of the plasma surrounding the actuators. The numerical method is based upon a high-fidelity time-implicit scheme, an implicit large-eddy-simulation approach, and domain decomposition in order to perform calculations on a parallel computing platform. Flow at a chord-based Reynolds number of 40,000 is considered in the investigation, which is characterized by laminar separation on the suction surface of the wing at low angles of attack. This separation then promotes transition to a more complex state, which can be modified by the use of plasma actuation. Several aspects of control are examined, including different actuator configurations, alternative plasma-force models, both continuous and pulsed modes of operation, and the magnitude of plasma force required for control.