Experimental Investigation of Airfoil Suction Side Flow Separation Control by Spanwise Nanosecond Actuation

Plasma flow control has become a newly-rising focus of international aerodynamics and aero thermodynamics fields. Experimental investigation of NACA 0015 airfoil stall separation suppression by span wise nanosecond discharge plasma aerodynamic actuation (NDPAA) is performed in the sake of improving the flow control ability for plasma flow control. The control effects influenced by various actuation parameters are systematically investigated. Experimental results show that using span wise NDPAA at the inflow velocity of 72 m/s, the critical stall angle of attack for NACA 0015 airfoil increases from 18° to 24° with a lift augmentation of 30.2% and drag reduction of 22.1%. Flow separation can be suppressed when the discharge voltage is larger than the threshold voltage. The optimum operation frequency for span wise NDPAA is the one which makes the Strouhal number equal to 1. NDPAA is more effective than microsecond discharge plasma aerodynamic actuation (MDPAA) in boundary layer flow control. The main mechanism for nanosecond discharge is shock effect. Shock effect is more effective in flow control than momentum effect.