Aerodynamic and Aeroacoustic Simulations of a Wind Turbine Airfoil Employing a New Transitional IDDES Method

Abstract

Abstract. The aerodynamic and aeroacoustic performance of wind turbines is strongly influenced by boundary layer transition, especially over thick trailing-edge airfoils commonly used near the blade root. Accurate prediction of transitional flow behavior is therefore critical for optimizing wind turbine efficiency and reducing noise emissions. In this study, a new transitional improved delayed detached-eddy simulation (IDDES) method, referred to as Tr-IDDES, is developed by coupling the γ–Reθt–k–ωSST transitional Reynolds-averaged Navier–Stokes (RANS) model into the IDDES framework. The Tr-IDDES method is applied to study the flow over the DU97FlatBack airfoil and is compared against the traditional fully turbulent IDDES (Ft-IDDES) method. The results demonstrate that the Tr-IDDES method successfully captures key transitional flow features such as laminar separation bubbles (LSBs) and boundary layer transition, which are not resolved by the Ft-IDDES model. It also demonstrates improved accuracy in predicting aerodynamic forces and better agreement with experimental results. Furthermore, the aeroacoustic behavior of the DU97FlatBack airfoil is studied using the IDDES methods and the Ffowcs-Williams and Hawkings equation for far-field noise prediction; the Tr-IDDES model more accurately predicts peak sound pressure levels and the spectral distribution of self-noise.