Hazem Ali Attia

MHD flow between two parallel plates with heat transfer

SummaryIn the present paper, the steady flow of an electrically conducting, viscous, incompressible fluid bounded by two parallel infinite insulated horizontal plates and the heat transfe through it are studied. The upper plate is given a constant velocity while the lower plate is kept stationary. The viscosity of the fluid is assumed to vary with temperature. The effect of an external uniform magnetic field as well as the action of an inflow perpendicular to the plates together with the influence of the pressure gradient on the flow and temperature distributions are reported. A numerical solution for the governing non-linear ordinary differential equations is developed.

Unsteady MHD flow near a rotating porous disk with uniform suction or injection

In this paper, the MHD flow of an incompressible, viscous and electrically conducting fluid above an infinite rotating porous disk is extended to flow starting impulsively from rest. The fluid is subjected to an external uniform magnetic field perpendicular to the plane of the disk. The effects of uniform suction or injection through the disk on the unsteady MHD flow are also considered. The governing nonlinear partial differential equations are solved numerically using the finite-difference approximations with a special treatment of the discontinuity between the initial and boundary conditions. The results of the numerical solution indicate some interesting effects of the magnetic field and the suction or injection velocities on the flow and prove that the steady state can be reached via a time-dependent process.

Effect of Hall current on the unsteady MHD flow due to a rotating disk with uniform suction or injection

Abstract The unsteady flow of a viscous conducting fluid due to the rotation of an infinite, non-conducting, porous disk in the presence of an axial uniform steady magnetic field is studied without neglecting the Hall effect. The fluid is acted upon by a uniform injection or suction through the disk. The relevant equations are solved numerically with a special technique to resolve the conflict between the initial and boundary conditions. The solution shows that the inclusion of the injection or suction through the surface of the disk in addition to the Hall current gives some interesting results.

Unsteady MHD couette flow and heat transfer of dusty fluid with variable physical properties

This paper studies the unsteady Couette flow and heat transfer of a dusty conducting fluid between two parallel plates with variable viscosity and electric conductivity. The fluid is driven by a constant pressure gradient and an external uniform magnetic field is applied perpendicular to the plates. The governing non-linear partial differential equations are solved numerically using finite differences. The effect of the variation in the viscosity and electric conductivity of the fluid and the uniform magnetic field on the velocity and temperature fields for both the fluid and dust particles is discussed.

Flow due to a rotating disk with Hall effect

Abstract The MHD flow due to an infinite disk rotating with a uniform angular velocity in the presence of an axial uniform magnetic field is examined. The induced magnetic fields are neglected but the Hall effect is considered. A numerical solution for the governing equations reveals that the Hall term has some interesting effects on the flow.

On the effectiveness of uniform suction-injection on the unsteady flow due to a rotating disk with heat transfer

The unsteady flow of an incompressible viscous fluid above an infinite rotating porous disk is studied with heat transfer. The effect of uniform suction or injection through the surface of the disk on the velocity and temperature distributions as well as the heat transfer is considered. Numerical solutions of the nonlinear equations which govern the hydrodynamics and energy transfer are obtained

Unsteady flow and heat transfer of viscous incompressible fluid with temperature-dependent viscosity due to a rotating disc in a porous medium

This paper studies the effect of a porous medium and temperature-dependent viscosity on the unsteady flow and heat transfer for a viscous laminar incompressible fluid due to an impulsively started rotating infinite disc. The unsteady axi-symmetric boundary layer equations are solved using three methods, namely, (i) perturbation solution for small time, (ii) asymptotic analysis for large time and (iii) the finite difference method together with the Keller box elimination technique for intermediate times. The solutions are obtained in terms of local radial skin friction, local tangential skin friction and local rate of heat transfer at the surface of the disc, for different values of the pertinent parameters: the Prandtl number Pr, the viscosity variation parameter e and porosity parameter m. The computed dimensionless velocity and temperature profiles for Pr = 0.72 are shown graphically for different values of e and m.

Unsteady Couette Flow of a Thermally Conducting Viscoelastic Fluid under Constant Pressure Gradient in a Porous Medium

Unsteady Couette flow through a porous medium of an incompressible non-Newtonian viscoelastic fluid between two parallel horizontal porous plates is studied. A constant pressure gradient in the axial direction and a uniform suction and injection normal to the surface of the plates are applied. The two plates are kept at different but constant temperatures, heat transfer through the conducting fluid is considered, and viscous dissipation is not neglected. Numerical solutions for the governing momentum and energy equations are obtained using the finite difference method. The results show that the porosity of the medium and the departure from the Newtonian characteristics of the fluid to viscoelasticity result in a drop in the velocity of flow and a drop in temperature and change the transient duration. The suction and injection reduce both the velocity and temperature at the middle plane.

MHD flow and heat transfer in a rectangular duct with temperature dependent viscosity and hall effect

Abstract In the present paper the laminar fully developed MHD flow and heat transfer through a rectangular duct of a viscous incompressible electrically conducting fluid is studied. A constant pressure gradient and an external uniform magnetic field are applied and the Hall effect is taken into consideration. The fluid viscosity is assumed to be temperature dependent with the assumption of constant wall heat flux axially and constant wall temperature peripherally. A numerical solution for the governing non-linear partial differential equations is obtained. The effect of the Hall term and the variable viscosity on the velocity and temperature fields is examined.

Unsteady flow of a non-Newtonian fluid above a rotating disk with heat transfer

Abstract The unsteady flow of an incompressible viscous non-Newtonian fluid above an infinite rotating disk is studied with heat transfer. The effect of the non-Newtonian fluid characteristics on the velocity and temperature distributions as well as the heat transfer is considered. Numerical solutions for the non-linear partial differential equations which govern the hydrodynamics and energy transfer are obtained.