Large-eddy simulation of the flow normal to a flat plate including corner effects at a high Reynolds number

Numerical investigations of the flow normal to a flat plate with the thickness ratio (thickness/height) of 0.02 have been carried out using three-dimensional large-eddy simulations (LESs). The Reynolds number (Re) based on the height of the plate (H) is 1.5×105. The plate corners are rounded with the curvatures of two different radii, i.e. r=0.01H and 0.005H. A low-frequency unsteadiness is indicated in the flow patterns and the flow switches alternately between the high and low drag regimes. This flow regime switch is more frequent in the sharp corner case (r=0.005H) than that in the smooth corner case (r=0.01H). The sharp corners complicate the flow pattern, increase the mean drag and the fluctuations of drag and lift forces on the plate, as well as the kinetic energy in the near wake. The instantaneous drag force is found to be reversely related to the instantaneous spanwise averaged recirculation length. The pressure and friction force components, Reynolds-averaged statistics distributions and the turbulent wake structures are also presented and discussed systematically.