Spin-up flow in a cylinder

Ekman pumping is the process by which a liquid interior spin-up to match a differentially rotating crust. Compressibility and buoyancy act to decrease the penetration of the spin-up flow throughout the interior. Movies show the extent to which regions of the interior are spun-up by Ekman pumping for different values of compressibility K and buoyancy N, where gravity is directed vertically towards the central plane.