Advancing Wind–Wave Research in the Weather Research and Forecast (WRF) Model: A Moving-Wave Implementation

Accurate characterization of airflow within the marine atmospheric boundary layer (MABL) is critical to assuring reliable and cost-effective wind energy production from offshore wind plants. The ocean wave field underlying the MABL is an important modulator of momentum and energy transfer between the atmosphere and ocean, thereby impacting the winds above. To investigate relationships between ocean waves, air-sea exchanges, and MABL wind characteristics of relevance to wind energy, we have implemented a moving wave surface boundary condition into the Weather Research and Forecast (WRF) model, enabling large-eddy simulations over phase resolved moving water waves. The implementation has been validated through various analytical laminar and turbulence flow cases, as well as by examining the wave growth rate under atmospheric forcing, all of which agree well with analytical solutions and results from the literature. Herein, we focus on evaluating the impact of non-equilibrated wind-wave conditions, where ocean surface waves evolve dynamically over time, with different wavenumbers exchanging energy due to nonlinear wave–wave interactions. Based on the numerical results, we conduct a detailed analysis of the temporal variations of wave-induced statistics within in the MABL and compare the results to more idealized wave treatments. This study offers insights into the mechanisms of wind–wave interactions within a complex ocean wave environment, as well as the relative importance of various wave dynamics on airflow characteristics of relevance to wind energy. These insights can be used to improve the accuracy of wind forecasts as well as ocean–atmospheric coupling within numerical models such as WRF used in offshore wind energy research.

* This research was supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Wind Energy Technologies Office. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-868575.