Effects of Surface Roughness on Aerodynamic Performance of a Wind Turbine Airfoil

The two-dimensional incompressible Navier-Stokes equations and the SST k-¿ turbulence model are used to investigate the aerodynamic performance of a wind turbine airfoil under clean and rough surface conditions. The DU 95-W-180 airfoil is analysized, which is widely used in wind turbines. The numerical simulation of the airfoil under clean surface condition is performed, and the numerical results have a good consistency with the experimental data. The studies in the effects of surface roughness on performance of the airfoil are mainly as follows:computation of the lift coefficient and the drag coefficient of the airfoil under different roughness heights on full surface and different roughness locations; the trends of the lift coefficient and the drag coefficient changing with the roughness heights and roughness locations; the critical value of roughness height and roughness location; the trends of the lift coefficient and the drag coefficient changing with the roughness heights at the critical locations. Furthermore, the unsteady flow field analysis of vortex shedding induced by the surface roughness is performed.