790 / 2024-09-19 13:58:17

The air-sea wave-induced effects on marine wind turbine array boundary layer and implications on offshore wind energy

Offshore wind energy; surface wave; marine atmospheric boundary layer; moving surface drag model; large eddy simulations; power output.

Offshore wind energy, with its advantages of large spatial distribution, high wind speed, and low turbulent disturbance, has emerged as a crucial development direction for future clean energy development. The dynamical coupling between wind and waves alters the characteristics of turbulent flow in the marine atmospheric boundary layer, posing new challenges in managing offshore wind energy. In this study, we investigate the influence of waves on airflow and wake turbulence of wind turbines using large eddy simulations. A moving surface drag model is employed to resolve the wave-indued darg on air flow above. Numerical experiments are designed to focus on impacts of wave ages, wave steepness, and turbine spacings on airflow within marine wind turbine array boundary layer and power generation. The results indicate that waves significantly affect the average wind speed and stress profiles downstream of wind turbines. Waves with higher propagation speeds accelerate the overlying winds, thereby increasing the upward momentum flux from sea surface. The turbulence intensity within the turbine wake is considerably disturbed by the wave phase shifting, attributed to the drag forces variation due to temporally varied wave height and its gradient. Overall, a faster propagating surface wave results in higher turbulent intensity and wake recovery efficiency, enhancing the power output of offshore wind farms.