Separation Control Using Plasma Actuators: Dynamic Stall Vortex Control on Oscillating Airfoil

A plasma actuator was used to control leading-edge flow separation and dynamic stall vortex on a periodically oscillated NACA 0015 airfoil. The effectiveness of the actuator was documented through phase-conditioned surface pressure measurements and smoke flow visualization records. The airfoil was driven in a periodic cycle corresponding to α = 15 deg+10deg sinwt. The results presented here are for a reduced frequency of k = ωc/2U ∞ = 0.08. Three cases of control with the plasma actuator were investigated: open-loop control with steady plasma actuation, open-loop control with unsteady plasma actuation, and closed-loop control with steady plasma actuation. For closed-loop control, the actuator was activated in selected portions of the oscillatory cycle based on angle-of-attack feedback. All of the cases investigated exhibited an increase in cycle-integrated lift with improvements in the lift-cycle hysteresis. In two cases, the pitch-moment stall angle was delayed and in one of these, the adverse negative moment peak was significantly reduced.