Large-eddy simulation of complex terrain flows: an application to the Perdigao site*

Detailed investigations and an enhanced understanding of atmospheric flows over complex terrain are necessary for many civil and engineering applications such as air pollution studies, weather prediction, wind energy harvesting, agriculture and  aviation. Due to advances in high-performance computing with accelerators, large-eddy simulations (LES) of complex terrain flows with spatial resolutions on the order of ten meters have become feasible. However, technical challenges such as accurate near-surface subgrid-scale parameterizations for complex terrains need to be overcome in order to obtain reliable results from LES. In the current work, results from LES of flow around the Perdigao terrain under neutrally-stratified conditions are presented.  A Cartesian immersed boundary method with a logarithmic reconstruction scheme and a near-surface subgrid-scale model are applied to simulate  separated flows over the double-humped terrain of Perdigao . Simulation results are compared against the field measurements, and the effect of turbulent inflow conditions on the simulations are investigated.