The airfoil-wake aerodynamic interaction of wind turbines was experimentally investigated using PIV(particle image velocimetry) technology.It analyzed the flow structure of downstream airfoil when the wake excited the leading edge

suction side and pressure side of airfoil

respectively.The results indicate that the helpful wake excitation is unsteady excitation which doesnt change main flow of downstream airfoil distinctly.The separation area at the suction side is restrained under the wake excitation at leading edge of airfoil when the upstream and downstream airfoils have the same incidence angle and appropriate axial-spacing.