ILES of flow over low-rise buildings: Influence of inflow conditions on the quality of the mean pressure distribution prediction

The paper presents an analysis of the deformation of the horizontal velocity profile in the flow approaching low-rise buildings for large eddy simulation on coarse grids. Build-up of velocity near the ground is observed as a consequence of momentum transfer from the outer flow to the ground level due to the fluctuating flow field. As a remedy, reduction of the turbulence intensity at the inflow boundary of the computational domain with respect to the experimental values is studied. The observation is that accurate prediction of the mean pressure distribution on the building surface is obtained when the inlet turbulence is reduced such that the deformation of the velocity profile in the flow approaching the building becomes small. For reliable mean pressure prediction, it is best not to reduce the inlet turbulence more than the minimum necessary to obtain a good velocity profile in the approaching flow.