Size of annular separation bubble around the inlet corner and viscous flow structure between two parallel disks

Abstract The annular separation bubble around the inlet corner and the radial flow between two parallel disks were investigated by means of flow visualization and numerical simulations to gain an understanding of the features of axisymmetric separation and reattachment in the inlet region. For the case with a sharp corner, the radius of the reattachment point depends only on clearance ratio, independent of Reynolds number in the turbulent flow regime where the reattachment point fluctuates randomly. For the cases with a rounded corner, the radius of reattachment point and the height of the bubble decrease with increasing corner roundness.