Marine atmospheric boundary layer modeling for offshore wind energy applications

Offshore wind energy offers abundant potential to provide clean, secure and reliable energy within the future generation mix. To fully exploit this potential, the industry is developing increasingly taller wind turbine towers and larger blades. As a result, the blades will be operating across an extended range of the marine atmospheric boundary layer. This requires an improved understanding of its vertical structure in order to reliably predict wind turbine power production and loads under a variety of operation scenarios. Furthermore, the underlying wave field introduces additional uncertainties due to the turbulence generated by the coupled air-sea dynamics. In order to enable further growth of the offshore wind industry, this study aims to contribute to advancing our knowledge of the marine atmospheric boundary layer dynamics through numerical modeling using large-eddy simulations. We propose a numerical approach explicitly capturing the sea-surface height dynamics through a hybrid level-set/immersed boundary method. The approach realizes a one-way air-sea coupling, in which the water velocity field is forced with potential flow theory and the air response is treated using the large-eddy simulation technique. We will perform a parametric study varying the wave state to capture scenarios representative of typical offshore wind turbine operations. The objective of the work is to understand how critical operational parameters, such as wind shear, hub-height turbulence intensity and integral scales, depend upon wave period, length and speed. These findings are expected to provide critical data that will inform the design of offshore wind turbines and optimize their operating strategies under diverse maritime conditions.