Large-Eddy Simulation of an offshore Mediterranean area

The aim of this study is gaining further understanding of the structure of the marine atmospheric boundary layer (MABL) and its interaction with the synoptic 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 optimise the structural design of offshore large wind turbines that now-a-days reach height up to 200 m. Large-Eddy Simulation (LES) have been performed and compared with offshore experimental data collected during the LASIE campaign performed in the Mediterranean in Summer 2007. Two simulations are performed: in the LES-NOFR run, the LES is left free to evolve without any external forcing, while in the LES-FR run a force-restore nudging technique has been implemented in LES, in order to force the model to the large-scale evolving situation. Model results have been compared against experimental soundings. Results show that the LES-FR outperforms the simulation without force-restore nudging for all the fields, demonstrating that incorporating changes in the large-scale features into the model is necessary in order to provide a realistic evolution of the meteorological fields at local scale.Thus, LES appears as a promising technique to be applied to the simulation of offshore cases, particularly suitable for wind energy applications.