Numerical Investigation of Aerodynamic Performance of Wind Turbine Airfoils with Ice Accretion

Abstract. One of the emerging problems in modern computational fluid dynamics is the simulation of flow over rough surfaces, wind turbine blades with ice on its surface for instance. An alternative method to numerically simulate rough surfaces instead of using a grid with y+ < 1 criterion is to use rough wall functions (RWFs) that models the flow behavior in case of the presence of roughness. This work aims to investigate different rough wall function models to find out the model that can provide the most accurate results with the lowest computational resources possible. This aim was achieved by comparing coefficients of lift and pressure resulting from CFD simulations with wind tunnel results of an airfoil with actual ice profiles collected from the site. After implementing new RWFs in OpenFOAM framework and validating the results with published experimental results, the comparison showed that momentum RWF provided the best agreement between simulation and experimental results while using only 25 % of the number of cells used with smooth RWF. The conclusions of this work will be applied in a simulation code within OpenFOAM framework to simulate airflow fields of wind turbines with ice accretion.