Wall-modeled Large Eddy Simulation of offshore wind turbine wake-wave spectrum interactions

The physics of wind waves play an important role in quantifying momentum transport at the air-sea interface. Significant knowledge gaps exist regarding the coupling between waves, the atmospheric boundary layer, and the operation of offshore wind turbines. This study uses a wall-modeled Large-Eddy Simulation (LES) approach to specify the unsteady wave stress due to a realistic wave field and understand the influence of surface waves on the dynamics of the atmospheric boundary layer and the offshore wind turbine generated wakes. The wave height distribution is calculated using a prescribed JONSWAP wave spectrum to simulate realistic oceanic conditions. The wave model calculates the total drag due to the entire spectrum through a linear superposition of the drag force due to each wave mode accounting for the relative velocity between the wind and the waves. The drag due to the unresolved portion of the wave field is calculated dynamically using a wave kinematics-based model. A variety of sea-state conditions (different spectrum peak characteristics and directional spread) are tested by leveraging the significantly lower computational cost of the wave model. The effect of waves on mean velocity profiles, wave-induced stress, wake meandering, and power production is quantified.