Abstract
The direct numerical simulation (DNS) is performed on the Ekman turbulent boundary layer around an isolated hill. Turbulence statistics such as the mean velocity profile are obtained. The streamline of the mean flow indicates that two mean vortices appear behind the hill and that they are asymmetric with respect to the vertical central plane along the mean flow direction. The reason of the asymmetry is discussed in conjunction with the system rotation and the pressure gradient force. The instantaneous vortex structures are visualized using the second invariant of the deformation tensor. Many small vortices are observed in the low pressure region behind the hill.
