Separation Control on High Angle of Attack Airfoil Using Plasma Actuators

摘要

This work involves the documentation and control of leading-edge flow separation that occurs over an airfoil at high angles of attack, well above stall. A generic airfoil shape (NACA 66_3-018) was used because of its documented leading-edge stall characteristics. It was instrumented for surface-pressure measurements that were used to calculate lift coefficients. Mean-velocity profiles downstream of the airfoil were used to determine the drag coefficient. In addition to these, smoke streakline flow visualization was used to document the state of flow separation. The airfoil was operated over a range of freestream speeds from 10 to 30 m/s, giving chord Reynolds numbers from 77 x 10~3 to 333 x 10~3. Two types of plasma actuator designs were investigated. The first produced a spanwise array of streamwise vortices. The second produced a two-dimensional jet in the flow direction along the surface of the airfoil. The plasma actuators were found to lead to reattachment for angles of attack that were 8 deg past the stall angle (the highest investigated). This was accompanied by a full pressure recovery and up to a 400% increase in the lift-to-drag ratio.