Unsteady Magnetohydrodynamic Couette Flow Research Articles

Numerical Solution of Unsteady MHD Couette Flow in the Presence of Uniform Suction and Injection with Hall Effects

In this paper, unsteady magnetohydrodynamic Couette flow is studied numerically for a viscous, incompressible and electrically conducting fluid between two infinitely long parallel porous plates, taking Hall current into account. Fluid flow within the channel is induced due to impulsive movement of the lower plate of the channel and fluid motion is subjected to a uniform suction and injection at upper and lower plates. Magnetic lines of force are assumed to be fixed relative to the fluid. Numerical solutions for primary and secondary velocities are obtained from the governing momentum equation by employing explicit finite difference method. Numerical solutions of the primary and secondary velocities are displayed graphically versus non-dimensional channel width variable $$y$$ for various values of Hall current parameter $$m$$ , magnetic parameter $$M$$ , suction/injection parameter $$S$$ and time $$t$$ whereas the numerical values of co-efficient of skin-frictions at the moving plate due to primary and secondary flows are presented in tabular form for different values of $$m$$ , $$M$$ , $$S$$ and $$t$$ .

Thermal decomposition of unsteady non-Newtonian MHD Couette flow with variable properties

Purpose – The purpose of this paper is to investigate the unsteady magnetohydrodynamic (MHD) Couette flow of an electrically conducting incompressible non-Newtonian third grade reactive fluid with temperature-dependent variable viscosity and thermal conductivity properties under isothermal surface conditions. Design/methodology/approach – The coupled non-linear partial differential equations for momentum and energy balance governing the transient problem are obtained and tackled numerically using a semi-discretization finite difference technique. Findings – The effects of various embedded thermophysical parameters on the velocity and temperature fields including skin friction, Nusselt number and thermal stability conditions are presented graphically and discussed quantitatively. Practical implications – The approach is applicable to modelling the complex physical phenomenon in MHD lubrications that occurs in numerous areas of engineering and industrial processes. Originality/value – This paper may be of industrial and engineering interest especially in understanding the combined effects of unsteadiness, variable thermophysical properties and magnetic field on the thermal stability condition for a reactive non-Newtonian third grade fluid under Couette flow scenario.

Ion slip effect on unsteady Couette flow of a dusty fluid in the presence of uniform suction and injection with heat transfer

The combined effects of Hall current, ion slip, viscous dissipation, and Joule heating on unsteady magnetohydrodynamic Couette flow with heat transfer of a dusty viscous incompressible electrically conducting fluid are studied under a constant pressure gradient. The fluid is subjected to an external uniform magnetic field and a uniform suction and injection perpendicular to the plates (y-direction). Numerical solutions for the constitutive equations are obtained using the method of finite differences. The effects of the magnetic field, Hall parameter, and ion slip parameter on the velocity and temperature distributions for both the fluid and particle phases are investigated in details and shown graphically. It is found that, the Hall current and ion slip parameters have a great effect on the fluid and dust velocities and temperature.

Unsteady MHD Couette flow of a generalized Oldroyd-B fluid with fractional derivative

This paper presents an analytical study for the magnetohydrodynamic (MHD) flow of a generalized Oldroyd-B fluid. The fractional calculus approach is used to establish the constitutive relationship model of a viscoelastic fluid. Exact analytic solutions for the velocity field and shear stress in terms of Fox H -function are obtained by means of the Laplace transform. The influence of the relaxation and retardation times, the orders of the time fractional derivative and the magnetic body force on the velocity and shear stress are analyzed. It is shown that the ordinary Oldroyd-B fluid, generalized second grade fluid and Maxwell fluid are the limiting cases of the presented results.

Unsteady Magnetohydrodynamic Couette Flow between Two Plates When One of the Plates is Subjected to Random Pulses

Previous investigators have studied the unsteady hydrodynamic and magnetohydrodynamic flow of viscous fluid between plates, cylinder etc. Generally these problems are solved assuming pressure gradient, external forces etc., of deterministic nature. 1-3) Recently attempts are being made to solve mechanical and hydrodynamic problems under stochastic body and surface forces. 4) Here we shall study a similar flow problem between two plates when one of the plates is kept fixed and the other is subjected to pulses of random strength applied at random instants of time parallel to the other plate. We can easily extend this solution to similar flow problems of elastic viscous fluid.