Impact force of ellipsoidal droplets on superhydrophobic surfaces

Abstract

Although wind turbine technology has emerged as an important renewable energy source, the unpredictable operating environment poses significant challenges in normal operation. Rain and hailstorm cause erosion on the leading edge of the Wind Turbine Blades (WTBs). As WTB get eroded, its performance diminishes and frequent repairs raise maintenance costs. The impact dynamics of non-spherical water droplets on a solid surface are investigated numerically in the present study. The finite volume method is utilized to solve the Navier-stokes equation and continuity equation, while the interface is accurately tracked through the implementation of the geometric Volume of Fluid (VOF) method. The effect of droplet morphology on the impact force is analyzed. Results show that the peak impact force increases with increasing aspect ratio at fixed Weber number. A correlation for dimensionless peak impact force based on aspect ratio is proposed. The maximum impact force obtained in this study can aid in the decision-making during the design and material selection of WTBs.