PIV study of the airfoil near wake flow

Detailed 2D velocity and vorticity fields were measured to investigate the turbulent near wake flow of NACA0012 airfoil with on-line cross-correlation PIV in low-speed wind tunnel. The Reynolds number based on chord length is 2.39 x 10⁵, the angles of attack are 0° and 4°. The experimental results show the existence of ordered vortex streets in the turbulent near wake. The vortex streets formed at the airfoil trailing edge region will fully develop and finally breakup when flowing downstream, and the wake flow changes from ordered to disordered. The near wake flow is dominated by the kinetic characteristics and dynamic mechanism of vortices. The paper mainly discuss the flow structure of the turbulent near wake flow, analyze the dynamic mechanism and the fluid instability of the vortex and vortex streets. Trailing edge flow control will change the interaction mechanism of the airfoil wake and the downstream object.