Imagine a cylindrical space settlement. It spins about an axis to create pseudo gravity for residents, who will think that radially outward is "downward". The shape of this settlement is a toroid with a rectangular cross section. Air is pumped in to make a habitable environment. Then, thrusters start spinning the settlement until 1g of pseudo gravity is attained. The space settlement is huge, so it spins at 1 rpm. What is the behavior of the air in this situation? In general, what is the behavior of a fluid in a slowly spinning toroid? My guess is that it behaves opposite of a stream. The air near the walls of the toroid is dragged along, but the air in the middle is slower. Therefore, the residents wouldn't feel a breeze unless they climbed a ladder to be right in between the toroid's walls. What's the behavior after a long time, and why? Does the viscosity of air play a role? Thanks.