Two-dimensional Flow around a Circular Barrier in a Rotating Spherical Shell

An experiment has been recently set up in the hydrodynamics laboratory to study the flow of fluid around a circular barrier. In a rotating spherical shell of liquid, a small cylindrical obstacle is moved zonally in mid-latitudes and observations are made of the resulting perturbed flow. If the flow relative to the obstacle is westerly, a strong anticyclonic circulation is set up faround the barrier and wave motions exist around the globe. When the basic flow is easterly with the same relative speed, no circulation is found, but the wake is very long and broad and the fluid in it has little motion relative to the obstacle. When viewed with respect to the shell, the obstacle moving eastward creates a strong westerly jet at its latitude.