Attached and separated rotating flow over a finite height ridge

We investigate the effect of rotation on the two-dimensional boundary layer on a ridge in high Reynolds number flow using numerical simulations to consider both shallow and deep flows as well as flow past a horizontal cylinder, motivated by experimental results by Machicoane et al. In all cases the boundary layer remains attached, even at large Reynolds numbers (Re), provided the Rossby number (Ro) is sufficiently small. At larger Ro, the flow detaches at sufficiently high Re to form a steady recirculating region in the lee of the ridge; at even higher Re no steady flow is found. The figure shows streamlines at Re=256000 for Ro=1.2, 1.5 and 2.