A note on the translation of a thin rod inside a cylinder

Abstract

The problem of a thin rod moving longitudinally along the axis of symmetry of a cylindrical vessel is examined for Newtonian and non-Newtonian liquids.

For non-Newtonian fluids, the inelastic power-law type solution predicts the experimental results particularly well. On account of wall effects, the induced pressure gradients are much greater for a Newtonian fluid than for a viscoelastic fluid. In fact, in the latter case, they may be considered negligible when the radius of the inner cylinder is small compared to the one of the outer cylinder.