A detached-eddy simulation study on assessing the impact of extreme wind conditions on load and wake characteristics of a horizontal-axis wind turbine

This study utilizes improved delayed detached-eddy simulation (IDDES) to investigate the impact of extreme wind conditions on a horizontal-axis wind turbine, as specified by the IEC-61400 standard. The employed IDDES has a hybrid formulation, where SST K-ω is used to model the turbulence in the boundary layers and large-eddy simulation (LES) is used to resolve turbulence in separated flow regions and the wake area. It also allows for switching to a wall-modelled LES approach, depending on the incoming turbulence content. The research focuses on extreme operating gust (EOG), extreme horizontal shear (EHS), and extreme vertical shear (EVS) conditions at two Tip Speed Ratios (TSR). The loadings and wake characteristics are compared to uniform inlet velocity results to highlight the effects of extreme winds. The novelty of this research lies in its comprehensive investigation of wake behavior under extreme wind conditions, providing valuable insights for improving wind farm layout design and reliability in challenging operational environments. The analysis shows that the impact of the TSR on wind turbine loadings during EOG, EVS, and EHS events is significant. During EOG events for a turbine operating at low TSR, the thrust force and bending moment reach 2.38 and 2.57 times their respective values in uniform inflow conditions, while at the optimal TSR, the thrust force and bending moment increase by only 25%. In all extreme wind cases, there is an escalation in turbulence within the wake, and wake meandering is observed in the EHS and EVS cases.