Unsteady Flow Analysis of an Oscillating Wind Turbine Airfoil Using OpenFOAM

Using OpenFOAM, numerical simulations of two-dimensional flow past a stationary and harmonically pitching wind turbine airfoil at a moderate value of Reynolds number (400000) have been carried out in the current study. Wind turbine blades are subject to different oscillating motions due to unsteady flow around them. Therefore, sinusoidal pitching motion as one of the basic motions in an unsteady oscillation is needed to be thoroughly investigated. This helps to reduce the loads on blades occurring due to dynamic stall phenomenon. The aim of this numerical study is to enhance the accuracy in prediction and analysis of unsteady phenomena around an oscillating NACA 6-series airfoil at near- and post-static stall regions. The experimental data possessed by the presenting authors are considered for validation. In most cases as the results demonstrate, the numerical simulation along with turbulence modelling using k-ω-SST with low-Re correction can accurately capture the physical phenomena related to unsteady pitching motion and hence, highly precise aerodynamic coefficients and pressure coefficients around the airfoil will be obtained at different stall-wise regions.