Comparison of the wake characteristics and aerodynamic response of a wind turbine under varying atmospheric conditions using WRF-LES-GAD and WRF-LES-GAL wind turbine models

A generalized actuator line model (GAL) is implemented in the Weather Research and Forecasting (WRF) (Skamarock and Klemp, 2008) model to carry out high-fidelity large-eddy simulations (LESs) of turbulent wind fields in stratified atmospheric boundary layer (ABL) flows and study the effects of atmospheric stability on the wake characteristics and aerodynamic response of a wind turbine (WT). The performance of Vestas V27 WT has been evaluated paying attention to the wind turbine wake behavior and the aerodynamic performance using the already available generalized actuator disk (GAD) and the recently implemented GAL model. Spatial distributions of mean velocity components, their variances and instantaneous vorticity in the wake of the wind turbine are analyzed by comparing the results from GAD and GAL approaches. Results of the wake velocity deficit profiles and wind turbine aerodynamic response have been compared with the experimental ones obtained in the Scaled Wind Farm Technology campaign and available LES data reported in the works of Doubrawa et al. (2020) and Jezequel et al. (2021). The results from the GAD and GAL models, including the aerodynamic effects of nacelle and tower, agree reasonably well with the results from other LES codes and experimental data, with minor differences between these two models regarding velocity deficits in the near-wake region and wind turbine response under varying atmospheric stability conditions. Overall, the GAL model is able to reproduce the observed wake behavior and the aerodynamic response of the Vestas V27 for the atmospheric conditions tested.