Improvements to the large-eddy simulation capability of the Weather Research and Forecasting model afforded by improved turbulence subfilter models are demonstrated in high-resolution simulations of flow over complex terrain. The simulations address improving the prediction and characterization of complex, turbulent flow in the lowest few hundred meters above the surface, in support of expanding wind energy applications. Results are shown for flow over both an isolated ridge and flow over terrain consisting of several hills and valleys of various shapes and sizes. The simulations cover a variety of wind speeds and stability conditions. The importance of boundary conditions as well as horizontal and vertical resolution, and the grid aspect ratio, are discussed.

This work was performed under the auspices of the U.S. Department of Energy by

Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

LLNL-ABS-405670