Magnetohydrodynamic Flow of a Couple-Stress Fluid Through a Non-Homogeneous Porous Medium with Oscillatory Suction and a Heat Source/Sink

Abstract

The present study investigates the heat and mass transfer characteristics of free convective flow of an incompressible, electrically conducting couple-stress fluid past a vertical porous plate embedded in a porous medium, in the presence of a uniform transverse magnetic field and internal heat source. The permeability of the porous medium and the suction velocity at the plate are assumed to vary periodically with time. The nonlinear governing partial differential equations describing the flow, thermal, and concentration fields are decomposed into steady and oscillatory components and subsequently reduced to a system of ordinary differential equations. An analytical solution is obtained using a regular perturbation technique. The effects of pertinent physical parameters on the velocity, temperature, and concentration distributions are examined and illustrated graphically, with particular emphasis on the influence of time-dependent suction and oscillatory permeability on the transport processes. The results demonstrate that periodic variations in permeability and suction significantly modify the flow structure as well as the thermal and solutal boundary layers of the couple-stress fluid. The results of this investigation are interesting for understanding transport phenomena in porous media with non-Newtonian fluids under periodically varying operating conditions.