Large eddy simulation of atmospheric boundary-layer flows under time-varying upstream inflows

In large eddy simulations (LES), a flat ground model and rough wedge ground models with different wedge heights were adopted to investigate near-surface wind field characteristics under condition of time-varying upstream inflows. In both flat ground model and rough wedge ground models, simulated results show that there is downdraft in peak period of gusty wind and updraft in valley period, respectively. Intensity of downdraft/updraft flows are related to ground roughness in upwind areas and amplitude of inflows. It follows that wind velocity and direction in atmospheric boundary layer always change over time in time-varying upstream inflows, which enhances transportation of mass and energy in actual atmospheric boundary layer.