Variable viscosity effects on unsteady MHD reactive third-grade fluid with asymmetric convective cooling within porous Couette device

Abstract

The principal motive of this study is to present a detailed account of the impact of both flow and energy profile of a time-dependent, incompressible, reactive third-grade fluid having low electrical conductivity besides variable viscosity through a porous channel accompanied by asymmetric cooling at the walls. The highly coupled equation of motion and energy manifested as non-linear partial differential equations are represented as algebraic equations using an implicit finite difference scheme and solved numerically by implementing the damped-Newton method. The solution obtained is eventually simulated using MATLAB and the resulting graphs representing the influence of non-dimensional parameters on the flow field and temperature field are discussed thoroughly. It is noted that an increase in γ values enhances non-Newtonian fluid properties which result in the thickening of the fluid and consequently fall in fluid velocity. An increase in reaction parameter and variable viscosity values remarkably enhances viscous heating source terms and contributes to the overall rise in fluid temperature. It is also observed that due to the nature of coupling of the source terms, for the majority of the non-dimensional parameters, there is a simultaneous increase or decrease in the momentum and energy profile of the fluid.