Abstract
A direct numerical simulation (DNS) is performed on the turbulent Ekman boundary layer over two-dimensional wavy terrain. In the upper part of the Ekman boundary layer, the geostrophic wind is driven by the balance between the atmospheric pressure gradient and the Coriolis force. The hills are arranged vertically to the direction of the geostrophic wind. The re-circulation vortex occurs in the valley between the hills. The flow in the direction parallel to the hill is dominant in the valley. The thickness of the Ekman boundary layer is significantly increased compared with the flow on the flat ground owing to the enhanced turbulence induced by the wavy terrain.
