Turbulence generation in a large eddy simulation of a wind farm coupling meso- and micro scale

Mesoscale circulation is of key importance for the study of wind farms in real conditions. Vertical mixing in Numerical Weather Prediction models is limited to resolutions on the order of 10³ meters and, consequently, is unable to capture the intermediate scale turbulent structures impinging the wind turbine rotor and their wake interaction. To reconstruct these intermediate scales variability, we performed Large Eddy Simulations of a wind farm in north Texas, resolving both the mesoscale wind variations and the microscale by coupling WRF with our in-house LES code. Five one-way nested domains are solved with WRF to model the wind mesoscale wind conditions, retaining a resolution of 50 meters at the wind farm. An additional high-resolution nested domain is performed with our in-house LES code in the innermost domain in WRF from where we obtained the inlet boundary conditions. Numerical results are compared against SCADA, LiDAR and meteorological measurements. The variability of the inflow in the innermost domain is such to generate turbulence intensities in good agreement with SCADA.