The observed motion of a sphere through a short, rotating cylinder of fluid

Abstract

The drag on a sphere has been measured as it moves through a slightly viscous fluid contained in a rotating cylinder that is short compared to the length of ‘Taylor columns’ created by the sphere motion. These results suggest that only when inertia effects are very much smaller than both viscous and Coriolis forces are the results of Moore & Saffman (1968) approached. Flow field observations show qualitative agreement with many of the features described in their paper but differ sufficiently to warrant a further, fairly extensive discussion. These differences are characterized by a marked fore and aft asymmetry in the shear layer and boundary-layer flows for all values of the parameters covered by this study.