Impact of variable viscosity on asymmetric fluid flow through the expanding/contracting porous channel: A thermal analysis

Abstract

This study aims to look at the problem of fluid flow through a rectangular channel between two parallel and permeable plates with expansion/contraction capability from two points of view. Considering that the fluid used in this study has properties such as non-Newtonian, Casson, incompressible, with temperature-dependent viscosity and MHD, and the fluid flow has properties such as two-dimensional, laminar unsteady, small electromagnetic force and electrical conductivity, an external magnetic field with uniform intensity. The governing equations for this problem with these features are non-linear partial differential equations (PDEs), which were converted into two non-linear ordinary differential equations (ODEs) using similarity transformation and solved analytically using the hybrid analytical and numerical (HAN-method). After using the similarity transformations, the profiles of similarity velocities, F(ξ), F′(ξ) and similarity temperature, θ(ξ) and their derivatives appear next to physical parameters such as A and R. As R changes from −10 to 10, the average values of F(ξ), F′(ξ), and θ(ξ) are increased while the value of A remains constant and positive, which shows that both plates have suction at the same time or injection at the same time. On the other hand, otherwise, when the value of A changes from −8 to 8, the average value of F(ξ) only increases, but the average values of F′(ξ) and θ(ξ) decrease while the value of R is constant and equal to 10. The results obtained in this article have been compared with other previous articles for validation. The most important novelty of this article is to express the changes in parameters using 3D and 2D contours. Changes in local skin friction coefficient and local Nusselt number were also investigated.