Effect of surface stretching on convective instabilities of Kármán flow of non-Newtonian Carreau fluid

Abstract

Linear convective instability analysis of non-Newtonian fluids has immense practical applications in the field of aerodynamics and engineering mechanics. The paper deals with linear convective instability analysis of laminar Kármán swirling flow of a non-Newtonian Carreau fluid over a radially stretchable rotating disk of infinite radius when the Coriolis force is significant in the boundary layer. In this paper, the velocity profiles for both shear-thinning and shear-thickening fluids the above-mentioned flow of Carreau model have been determined under stretch boundary condition. By using the Chebyshev collocation method, a study of convective instability has been carried out in order to perform a stability analysis of the flow and determine the neutral stability curves. The stability curves reveal that the bottom disk’s surface stretching has a globally stabilizing effect on the fluid exhibiting shear-thinning flow behaviour and a globally destabilizing effect on shear-thickening flow behaviour. To verify the above physical facts, the flow has been subjected to an energy analysis at the same time.