Modelling offshore wind and turbulence with a multi-scale coupled atmosphere-wave framework

Accurate knowledge of turbulence and winds is essential for wind farm planning and operation. In offshore environments, these parameters are strongly influenced by continuously evolving surface waves. Therefore, atmosphere-wave coupling is critical for realistic simulations. Additionally, resolving turbulence requires spatial resolutions beyond the mesoscale. 

In this study, we apply a coupled atmosphere–wave modelling system configured in large-eddy simulation (LES) mode to evaluate whether such an approach can reproduce wind and turbulence characteristics at heights relevant for offshore wind energy. We use the Coupled Ocean–Atmosphere–Waves–Sediment Transport (COAWST; Warner et al., 2010) framework with the Weather Research and Forecasting (WRF) model and the Simulating WAves Nearshore (SWAN) model activated. Coupling between the atmosphere and wave components is achieved through the Wave Boundary Layer Model (WBLM; Du et al., 2017, 2019). A nested-domain WRF configuration is employed, with the innermost LES domain centered on the FINO3 research platform. A parallel control simulation is performed using stand‑alone WRF without wave coupling. 

We focus on a long period where both mast and lidar measurements are available, and no wind farm in the direct vicinity was present (July 2013–June 2014). Simulated mean wind speed and turbulence characteristics are compared with the measurements to quantify the added value of explicit wave modelling as well as LES modelling for offshore wind‑energy applications. 

References 

Du, J., Bolaños, R., & Larsén, X.G. (2017). The use of a wave boundary layer model in SWAN. Journal of Geophysical Research: Oceans, 122(1), 42–62. https://doi.org/10.1002/2016JC012104 

Du, J., Bolaños, R., Larsén, X. G., & Kelly, M. (2019). Wave boundary layer model in SWAN revisited. Ocean Science, 15(2), 361–377. https://doi.org/10.5194/os-15-361-2019 

Warner, J. C., Armstrong, B., He, R., & Zambon, J. B. (2010). Development of a Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST) Modeling System. Ocean Modelling, 35(3), 230–244. https://doi.org/10.1016/j.ocemod.2010.07.010 

 

Acknowledgements 

This work is funded partly by the CETPartnership, the Clean Energy Transition Partnership under the 2023 joint call for research proposals, co funded by the European Commission (GA 101 069750 ) and with the funding organizations as detailed on https://cetpartnership.eu/funding-agencies-and-call-modules and by the Independent Research Fund Denmark (Danmarks Frie Forskningsfond DFF) through the ‘Multi-scale Atmospheric Modeling Above the Seas (MAMAS)’ project (nr. 0217-00055B).