Effect of Offshore Wind Farms on Ocean Waves

Offshore wind farms may impose influence on marine meteorology and ocean surface waves when the scale of wind farms is large. To investigate the effects of offshore wind farms on wave evolution, we perform large eddy simulation (LES) of a fully developed wind turbine array boundary layers. The sea-surface wave field is simulated using a high-order spectral method based on potential flow theory. The wave and wind fields are dynamically coupled in the simulation. At each time step, the wave field provides the surface geometry and velocity to the wind field as bottom boundary conditions, and wind field gives wave field the air pressure as the wind forcing on the wave evolution. For the modeling of subgrid-scale stress and scalar flux in LES, we use a scale-dependent Lagrangian dynamic model, which is particularly suitable for the complex turbulence wind field above the irregular ocean wave field. An actuator disk model is used to represent turbine-induced forces, while Boussinesq approximation is utilized to account for thermal stratification effects. In this study, a variety of wind fields and wave fields under fully developed and fetch-limited conditions are examined. Our analyses focus on the response of wave spectrum, wave height, wave steepness, and spectrum peak to the modified wind forcing affected by the offshore wind farms. Our results indicate that the effects of offshore wind farms on the wave field is dependent on the conditions of wind, wave, and atmosphere stratification.