Surface roughness evolution of wind turbine blade subject to rain erosion

Leading edge erosion of wind turbine blades causes roughening of the blade’s surface, leading to a reduction of energy production. This paper presents a computational model for the prediction of the roughness evolution of the blade’s surface, based on fatigue damage calculations and rain droplet impact simulations. A novel method for the calculation of material roughness due to multiple random liquid impacts was developed, by considering damage concentration in areas where sharpness due to material removal is formed. Material removal was governed by fatigue damage values. The computational model was compared to roughness measurements from a sample tested in a rain erosion tester. The outputs of this model are 3D surfaces resembling the roughness of the protective coating layer as well as the evolution of surface roughness parameters and mass loss throughout time.