Rotating Flows Over a Rotating Disk for a Class of non-Newtonian Fluids

Abstract

Axisymmetric rotating flows over a rotating disk for non-Newtonian fluids of Reiner-Rivlin type are calculated by means of an adjustable local boundary-layer approximation, which was recently introduced by the authors. Variation of the dynamic similarity parameter, which characterizes the non-Newtonian fluid, shows that secondary motions of stagnation, wake, or cell type can exist. The beginning of instability in Bödewadt-type motions, which indicates laminar flow separation from the surface of the disk is shifted to higher Reynolds numbers for non-Newtonian fluids. Furthermore, the largest tangential shear stress at the surface is exhibited by laminar flows of Newtonian fluids.