Secondary Flows associated with the Weissenberg Effect

Abstract

NORMAL stresses cause some of the more vexing characteristics of flows involving non-Newtonian fluids. One manifestation of normal stresses is the appearance of rod climbing (the Weissenberg effect) in a system where a rotating shaft is immersed in a non-Newtonian fluid. Another manifestation is to reverse the sense of secondary flows (compared with the direction observed in flows with Newtonian fluids) near rotating spheres and cones (compare Giesekus1). Although the Weissenberg effect is presented in a number of treatises, for example, Coleman2 and Frederickson3, the detailed structure of the flow has apparently not been reported. It is customary, moreover, to simplify mathematical analyses by assuming that the flow field in the space between rotating cylinders is the familiar Couette flow. With a non-Newtonian liquid the flow can in fact be rather different, as is shown in the results presented here.