Basic Study on Classification of Fine Particles in Almost Rigidly Rotating Flow. 3rd Report, Conditions of Occurrence of a Stable Regime of Almost Rigidly Rotating Flow.

Abstract

We have experimentally investigated the conditions of occurrence of a steady axisymmetric flow regime and the velocity distributions in the interior region and the Stewartson layer for an almost rigidly rotating. through-flow in a concentric-sphere system and a disk-cylinder system (the rotor and housing walls consist of disk and cylinder surfaces). The conclusions are as follows. (1) The steady axisymmetric flow regime occurs when ε≤2.0E0.48 in both systems, where ε and E are the Rossby and Ekman numbers, respectively. (2) The experimental results of the velocity distributions in the interior region agree with their linear analytical solutions. (3) The absolute value of the axial velocity component increases downstream and with a decrease of the Ekman number in the Stewartson layer along the rotor in the disk-cylinder system. (4) The reverse flow in the Stewartson layer which occurs in the gap between the rotor and housing walls is prevented by narrowing the gap.