Leading-Edge Surface-Manipulated Flow Separation from an Airfoil

A method to control leading-edge surface-manipulated flow separation from an airfoil, is demonstrated. A Piezoelectric ceramic THUNDER actuators used for this method is placed at the suction side near the leading edge of the airfoil. A closed-circuit low-speed wind tunnel along with a 2.4-m-long square working section was used for this study. The airfoil used for this study is made of a slot of 0.07c in width on the upper surface and 0.08c downstream of the leading edge. A signal generator was also used to generate actuating sinusoidal signals, while a piezodriver amplifier was used for amplification. It was observed that the actuator and the thin plate can create a dynamically nonlinear system and its dynamic response depends on the activating frequency. The high-frequency perturbation is able to increase the static-stall angle of attack, which subsequently decrease the drag and increase the lift and lift-to-drag ratio.