Osman Anwar Bég

Transient magneto-micropolar free convection heat and mass transfer through a non-Darcy porous medium channel with variable thermal conductivity and heat source effects

Abstract The laminar, fully developed, transient magnetohydrodynamic (MHD) free convection heat and mass transfer of an electrically conducting micropolar fluid between two vertical plates containing a non-Darcy porous medium with heat generation/absorption and asymmetric wall temperature and concentration has been discussed in this article. A similarity transformation is used to render the problem into a system of coupled, partial, differential equations, which are solved using the finite-element method (FEM). The solutions are validated with a robust finite difference method (FDM) solver. The present work examines the effect of Darcian parameter, Forchheimer parameter, heat absorption/generation parameter, vortex viscosity parameter, buoyancy ratio parameter, magnetic parameter, and variable thermal conductivity parameter on velocity, angular velocity, temperature and concentration profiles. Space—time graphs of velocity and microrotation are also plotted to provide a better perspective of the flowfield evolution with respect to time. Applications of the study may arise in, for example, packed-bed chemical reactors, materials processing, magnetic field control of chemical engineering transport processes in filter media, purification of hydrocarbons with electromagnetic fields, etc.

DTM Simulation of Peristaltic Viscoelastic Biofluid Flow in Asymmetric Porous Media: A Digestive Transport Model

A biofluid dynamics mathematical model is developed to study peristaltic flow of non-Newtonian physiological liquid in a two-dimensional asymmetric channel containing porous media as a simulation of obstructed digestive (intestinal) transport. The fractional Oldroyd-B viscoelastic rheological model is utilized. The biophysical flow regime is constructed as a wave-like motion and porous medium is simulated with a modified Darcy-Brinkman model. This model is aimed at describing the digestive transport in intestinal tract containing deposits which induce impedance. A low Reynolds number approximation is employed to eliminate inertial effects and the wavelength to diameter ratio is assumed to be large. The differential transform method (DTM), a semi-computational technique is employed to obtain approximate analytical solutions to the boundary value problem. The influences of fractional (rheological material) parameters, relaxation time, retardation time, amplitude of the wave, and permeability parameter on peristaltic flow characteristics such as volumetric flow rate, pressure difference and wall friction force are computed. The present model is relevant to flow in diseased intestines.

Spectral quasilinear numerical simulation of micropolar convective wall plumes in high permeability porous media

Laminar natural convection plume of a microstructural non-Newtonian fluid along a vertical surface about a line heat source in a saturated high permeability porous medium is studied. The transformed non-linear boundary value problem is solved numerically using a rigorously tested SQLM algorithm, which combines a spectral collocationmethod with the quasilinearization method (QLM). The effects of Grashof number, Prandtl number, Darcy number and Eringen micropolar rheological material parameters are examined. Excellent stability and convergence of the spectral method is demonstrated. Validation of solutions with the Keller box finite difference is included. Applications of the study arise in geological (petroleum) fluid dynamics.