Hydrodynamic and hydromagnetic stability

Stability analysis of soret-driven double-diffusive convection of Maxwell fluid in a porous medium

Fully-developed free-convective flow of micropolar and viscous fluids in a vertical channel

This study considers steady, laminar flow of two viscous, incompressible, electrically-conducting and heat-generating or absorbing immiscible fluids in an infinitely-long, impermeable parallel-plate channel filled with a uniform porous medium. A magnetic field of uniform strength is applied normal to the flow direction. The channel walls are assumed to be electrically nonconducting and are maintained at two different temperatures. When present, the porous medium is assumed to act as an electrical insulator and that it is in local thermal equilibrium with the fluid. The transport properties of both fluids are assumed to be constant. This study is expected to be useful in understanding the influence of the presence of slag layers on the flow and heat transfer aspects of coal-fired Magnetohydrodynamic (MHD) generators when the porous medium is absent and the effects of thermal buoyancy and a magnetic field on enhanced oil recovery and filtration systems where the porous medium is present. The problem is formulated by employing the balance laws of mass, linear momentum, and energy for both phases. Continuous conditions for the velocity and temperature as well as the shear stress and heat flux of both phases at the interface are employed

Flow of Two-Immiscible Fluids in Porous and Nonporous Channels

The problem of unsteady oscillatory flow and heat transfer of two viscous immiscible fluids through a horizontal channel with isothermal permeable walls has been considered. The partial differential equations governing the flow and heat transfer are solved analytically using two-term harmonic and non-harmonic functions in both fluid regions of the channel. Effects of physical parameters such as viscosity ratio, conductivity ratio, Prandtl number and frequency parameter on the velocity and temperature fields are shown graphically. It is observed that the velocity and temperature decrease as the viscosity ratio increases, while they increase with increases in frequency parameter. The effect of increasing the thermal conductivity ratio also suppresses the temperature in both fluid regions. The effect of periodic frequency on the flow is depicted in tabular form. It is predicted that both the velocity and temperature profiles decrease as the periodic frequency increases.

Unsteady two-fluid flow and heat transfer in a horizontal channel

The onset of Lapwood-Brinkman convection using a thermal non-equilibrium model

The onset of double diffusive convection in a two component couple stress fluid layer with Soret and Dufour effects has been studied using both linear and non-linear stability analysis. The linear theory depends on normal mode technique and non-linear analysis depends on a minimal representation of double Fourier series. The effect of couple stress parameter, the Soret and Dufour parameters, and the Prandtl number on the stationary and oscillatory convection are presented graphically. The Dufour parameter enhances the stability of the couple stress fluid system in case of both stationary and oscillatory mode. The effect of positive Soret parameter is to destabilize the system in case of stationary mode while it stabilizes the system in case of oscillatory mode. The negative Soret parameter enhances the stability in both stationary and oscillatory mode. The couple stress parameter enhances the stability of the system in both stationary and oscillatory modes. The Dufour parameter increases the heat transfer while the couple stress parameter has reverse effect. The Soret parameter has negligible influence on heat transfer. Both Dufour and Soret parameters increases the mass transfer while the couple stress parameter has dual effect depending on the value of the Rayleigh number.

An analytical study of linear and non-linear double diffusive convection with Soret and Dufour effects in couple stress fluid

Two-phase magnetohydrodynamic flow and heat transfer in an inclined channel

Magnetohydrodynamic heat transfer in two phase flow

The problem of fully developed free convection two fluid magnetohydrodynamic flow in an inclined channel is investigated. The governing momentum and energy equations are coupled and highly nonlinear due to dissipation terms, solutions are found employing perturbation technique for small values of Pr · Ec (=ɛ) the product of Prandtl number and Eckert number. Effects of Grashof number, Hartmann number, inclination angle, the ratios of electrical conductivities, viscosities and heights of two fluids on the flow are explored. It is observed that the flow can be controlled effectively by suitable adjustment of the values for the ratios of heights, electrical conductivities and viscosities of the two fluids.

M. S. Malashetty

Papers

The onset of Lapwood-Brinkman convection using a thermal non-equilibrium model

An analytical study of linear and non-linear double diffusive convection with Soret and Dufour effects in couple stress fluid

Two-phase magnetohydrodynamic flow and heat transfer in an inclined channel

Magnetohydrodynamic heat transfer in two phase flow

Convective magnetohydrodynamic two fluid flow and heat transfer in an inclined channel