Leading-Edge Separation Control Using Alternating-Current and Nanosecond-Pulse Plasma Actuators

Abstract

Wind-tunnel experiments were conducted to quantify the effectiveness of ac and nanosecond-pulse single dielectric barrier discharge plasma actuators to suppress leading-edge stall on a NASA Energy Efficient Transport airfoil at Mach numbers up to 0.4 and chord Reynolds numbers up to . The airfoil model was designed to have a removable leading edge to accommodate two different leading-edge plasma-actuator designs, either with a thick ceramic or a thin Kapton dielectric layer. The exposed electrode for both plasma actuators was located at the leading edge of the airfoil. The covered electrode for both was on the suction side of the leading edge. The model was mounted on stages that measured the lift and drag forces and the pitching moment about the quarter-chord location. Both steady and unsteady ac plasma-actuator operation were examined. By its nature, the nanosecond-pulse plasma actuator only operates in unsteady operation. The optimal unsteady frequencies with regard to lift, lift to drag, and pitch moment for both actuators were examined. Although operating on different principles, both plasma-actuator approaches were able to increase the maximum lift coefficient and stall angle of attack for the full range of Mach numbers. Mach number scaling of the ac actuator lift enhancement is presented.