Numerical and experimental research of flow control on an NACA 0012 airfoil by local vibration

A flow control technique by local vibration is proposed to improve the aerodynamic performance of a typical airfoil NACA 0012. Both wind-tunnel experiments and a large eddy simulation (LES) are carried out to study the effects of local vibration on drag reduction over a wide range of angles of attack. The application parameters of local vibration on the upper surface of the airfoil are first evaluated by numerical simulations. The mounted position is chosen at 0.065–0.09 of chord length from the leading edge. The influence of oscillation frequency is investigated both by numerical simulations and experiments. The optimal frequencies are near the dominant frequencies of shear layer vortices and wake vortices. The patterns of shear vortices caused by local vibration are also studied to determine the drag reduction mechanism of this flow control method. The results indicate that local vibration can improve the aerodynamic performance of the airfoil. In particular, it can reduce the drag by changing the vortex generation patterns.