Numerical Study of Axisymmetric Vortex Breakdown Flows in an Open Cylindrical Container with Rotating Bottom Wall.

Abstract

Although extended studies have been made on the vortex breakdown inside a cylindrical container by means of numerical simulation, majority of the studies conducted on this flow treated the case of flows inside a closed container with bottom and top disks. The occurrence of vortex breakdown in a cylindrical container is considered to be influenced by the swirling velocity component and the upstream vorticity distribution. Therefore, in the present study, by changing the top disk non-slip boundary condition to the free-slip boundary condition, the influence of the free surface on the emergence of vortex breakdown is investigated in detail. Numerical results are compared with the existing experimental study and novel flow behavior is noticed for container with small aspect ratios.