Flows induced in a cylinder with both end walls rotating

The flow field inside a cylindrical container induced by the rotation of the top and bottom end walls with a fixed sidewall is described. For this problem, this paper shows that stagnation points occur along the axis of rotation between the midplane of symmetry and the rotating end walls for appropriate values of the characteristic parameters, viz., the Reynolds number and the aspect ratio of the container. Aspect ratios of 0.5, 0.8, 1.0, and 1.5 were examined over a range of Reynolds numbers from 100 to 2000. As the Reynolds number increased beyond a critical value a recirculation zone surrounding a columnar vortex core in the meridional-plane flow pattern is predicted to occur near the midplane. This toroidal vortex is different from the type B vortex breakdown phenomenon that occurs in cylindrical containers with only one end wall rotating.