Abstract
The presence of rain-induced leading edge erosion of wind turbine blades necessitates the development of erosion models. The relative impact velocity between rain droplets and a rotating blade is an essential parameter for erosion modelling based on which the erosion damage rate of a wind turbine blade is calculated. The environmental parameters that govern such erosion damage have site-specific variations and differ for turbines installed at onshore and offshore locations. The present paper tries to provide guidelines for erosion modelling and investigates the differences in erosion of blade due to: (1) varying rainfall conditions modelled using different droplet size distributions for onshore and offshore locations, while interacting with (2) winds of varying turbulence intensities and (3) wave-induced loads. Aero-hydro-servo-elastic simulations are carried out for an onshore wind turbine and a monopile-supported offshore wind turbine. Further, erosion variables such as the relative impact velocities and the associated erosion damage rate of a blade are analysed for various blade azimuth angles. The study shows that the rainfall intensity and turbulence intensity influences the impact velocity and pressure minorly but has a substantial effect on the overall erosion damage rate. Also, a significantly higher erosion damage rate is found for blades exposed to offshore rainfall conditions than for blades under onshore rainfall conditions. Furthermore, no substantial influence on erosion is found because of wave-induced loads.