Improved performance of k − ω SST turbulence model in predicting airfoil characteristics for a wide range of airfoil thicknesses

Abstract

A variety of airfoils designed for wind turbine rotor blade applications were simulated with k − ω shear stress transport (SST) turbulence model in its standard form, the k − ω SST turbulence model with a modified a 1 constant (referred to as the a 1 method), the Spalart-Allmaras turbulence model, and the panel method XFoil. To assess their performance, the results of airfoil lift, drag, and coefficient of pressure were compared against available wind tunnel data, where available. The standard k −ω SST turbulence model is found to over-predict Reynolds shear stresses, delay the flow separation, and under-predict the separated-flow region on the airfoil’s suction side. Airfoil thicknesses between 11% and 36% of the chord length were studied. Using a modified a 1 constant, some airfoils exhibited up to a 20% improvement in the prediction of lift and drag coefficients within the post-stall range of angle of attack (AoA). It is important to note that the a 1 method’s applicability and effectiveness is specifically tested for airfoils, and its performance is highly dependent on the airfoil geometry.