Large-eddy simulation of an offshore Mediterranean area

The aim of this study is to gain further understanding of the structure of the marine atmospheric boundary layer (MABL) and its interaction with ynoptic-scale forcing. A possible application of this study is to simulate mean and turbulent spatial and temporal structure of the marine boundary layer in order to optimize the structural design of offshore large wind turbines that today reach heights up to 200 m. Large-eddy simulations (LESs) have been performed and compared with offshore experimental data collected during the LASIE campaign performed in the Mediterranean during summer 2007. Two simulations are performed: one where the LES is left free to evolve without any external forcing, and one where a force restoration nudging technique has been implemented in LES in order to force the model to the evolving large-scale situation. Model results have been compared against experimental soundings. Results show that for all the calculated fields the nudged LES outperforms the simulation without nudging, demonstrating that incorporating changes in the large-scale features is necessary in order to provide a realistic evolution of the modelled meteorological fields at local scale. Thus, appropriately nudged LES appears as a promising technique to be applied to the simulation of offshore cases, particularly suitable for wind energy applications.