Lift enhancement of an airfoil and an unmanned aerial vehicle by plasma Gurney flaps

A novel conception of the plasma Gurney flap is proposed, which consists of two dielectric barrier discharge plasma actuators attached to the airfoil pressure surface near the trailing edge. The upstream and downstream plasma actuators can be actuated individually, where it is found that the most significant control effect takes place when only the downstream plasma actuator is turned on. Such optimal conception is applied to a NACA 0012 airfoil and an unmanned aerial vehicle without and with flaps deflection. The present proposed plasma Gurney flap is found to have the similar lift-increment effect and the control mechanism with the conventional Gurney flap. A large-scale counterclockwise recirculation region forms over the airfoil pressure surface near the trailing edge with plasma control, acting as the virtual aeroshaping effect. Consequently, both the suction over the upper surface and the pressure over the lower surface are increased. Thus, the plasma Gurney flap can increase the lift coefficient before the stall angle, reduce the drag coefficient, and increase the lift-to-drag ratio at small angles of attack. In addition, the plasma Gurney flap has additional advantages, such as active control ability and small device drag, making it a very attractive lift-enhancement technique for aeronautical applications.