A Novel Computational Approach to High Fidelity Wind Turbine Flow Simulation

A novel computational fluid dynamics (CFD) methodology has been developed as a new approach to wind resource assessment. An unsteady Reynolds-Averaged Navier-Stokes (URANS) CFD solver with advanced Large Eddy Simulation (LES)-based turbulence models has been tightly coupled with a vorticity-velocity CFD solver. This coupling creates a consistent hybrid overset methodology based solely on the resolution of the Navier-Stokes equations that includes both computational efficiency and improved accuracy. Because the hybrid solver is based on government research and commercial codes that are supported and are regularly updated with new state-of-the-art algorithms and methodologies, this approach also provides a robust, "carefree" platform on which to base computations. This hybrid model has been applied to wind-turbine components used in Phase VI of the National Renewable Energy Laboratory (NREL) Unsteady Aerodynamics Experiment. The accuracy and feasibility of this approach are assessed with correlations to experimental data and standalone URANS simulations. The new hybrid approach is shown to provide comparable (or better) wake characteristics and blade loading as the CFD solver using a fraction of the grid and computational time.