Effect of the leading-edge protuberances on the aeroacoustic and aerodynamic performances of the wind turbine airfoil

Based on the restraining effect of the leading-edge protuberances (LEPs) on flow separation, this work focuses analyzing the aeroacoustic and aerodynamic performances for the wind turbine airfoil with LEPs near the outboard region of the blades, by using the experimental testing and numerical calculation methods. The associated flow patterns for the aeroacoustic and aerodynamic performances are revealed within the pre-stall and post-stall regions. The shedding of the separation vortices enhances the instability of the laminar boundary layer, generating the aerodynamic noise from the wind turbine airfoil. The LEPs suppress the generation of the tonal noise in pre-stall region by changing the distribution and reducing the intensity of the trailing edge shedding vortices. Moreover, LEPs can improve the aerodynamic performance of the wind turbine airfoil greatly by inhibiting the flow separation at a high inflow angle of attack. As a flow control method for the wind turbine blades, LEPs will help to improve the aeroacoustic performance of the blades under normal inflow wind con-ditions, and the aerodynamic performance under extreme wind situations where the inflow wind changes on a large scale frequently.