Hybrid vortex simulations of wind turbines using a three-dimensional viscous-inviscid panel method

A hybrid filament-mesh vortex method is proposed and validated to predict the aerodynamic performance of wind turbine rotors and to simulate the resulting wake. Its novelty consists of using a hybrid method to accurately simulate the wake downstream of the wind turbine while reducing the computational time used by the method. The proposed method uses a hybrid approach, where the near wake is resolved by using vortex filaments, which carry the vorticity shed by the trailing edge of the blades. The interaction of the vortex filaments in the near vicinity of the wind turbine is evaluated using a direct calculation, whereas the contribution from the large downstream wake is calculated using a mesh-based method. The hybrid method is first validated in detail against the well-known MEXICO experiment, using the direct filament method as a comparison. The second part of the validation includes a study of the influence of the time-integration scheme used for evolving the wake in time, aeroelastic simulations of the National Renewable Energy Laboratory 5MW wind turbine and an analysis of the central processing unit time showing the gains of using the hybrid filament-mesh method. Copyright (c) 2017 John Wiley & Sons, Ltd.