Sanatan Das

Hall Effects on Unsteady MHD Free Convective Flow Past an Accelerated Moving Vertical Plate with Viscous and Joule Dissipations

effects on an unsteady MHD free convective flow of a viscous incompressible electrically conducting fluid past a uniformly accelerated vertical plate in the presence of a uniform transverse applied magnetic field have been investigated on taking viscous and Joule dissipations into account. The governing partial differential equations have been solved numerically by applying a Crank - Nicolsons type of implicit finite difference method with a tri-diagonal matrix manipulation and an iterative procedure. The variations of the fluid velocity components and temperature distribution are presented graphically. It is found that the fluid velocity components are significantly affected by Hall parameter. An increase in Eckert number leads to rise in the fluid velocity components and temperature distribution. Further, it is found that the magnitude of the shear stress components at the plate increase with an increase in either Hall parameter or Eckert number or Prandtl number. The rate of heat transfer at the plate decreases with an increase in either Eckert number or Prandtl number or time.

Radiation Effects on Unsteady MHD Free Convective Couette Flow of Heat Generation/Absorbing Fluid

effects on free convection MHD Couette flow of a viscous incompressible heat generating fluid confined between vertical plates have been studied. The governing equations are solved analytically using the Laplace transform technique. The variations of velocity and fluid temperature are presented graphically. It is observed that the velocity decreases with an increase in either magnetic parameter or radiation parameter or generation parameter or Prandtl number. It is also observed that the velocity increases with an increase in either Grashof number or time. An increase in either radiation parameter or Prandtl number leads to fall in the fluid temperature. It is seen that the fluid temperature increases with an increase in either heat generation parameter or time. Further, it is seen that the absolute value of shear stress at the moving plate increases with an increase in either magnetic parameter or radiation parameter while it decreases with an increase in either heat generation parameter or Prandtl number. The rate of heat transfer increases with an increase in either Prandtl number or heat generation parameter or time.

Hall Effects on Unsteady MHD Flow Between Two Rotating Disks with Non-Coincident Parallel Axes Embedded in a Porous Medium

Hall effects on an unsteady MHD flow of a viscous incompressible electrically conducting fluid between two rotating disks with non-coincident parallel axes embedded in a porous medium have been studied. The governing equations have been solved analytically using the Laplace transform technique. The effects of rotation parameter, Hall parameter, Hartmann number and Darcy number have been considered on the flow characteristics and illustrated by graphs. It is observed that the velocity components are significantly affected by Hall parameter and Darcy number. The velocity components increase near the lower disk whereas they decrease near the upper disk with an increase in either rotation parameter of disk or rotation parameter of axis. Further, the torque experienced by the disks increases with an increase in either Hartmann number or rotation parameter while it decreases with an increase in either Hall parameter or Darcy number.

Hall Effects on Hydromagnetic Rotating Couette Flow

The hydromagnetic Couette flow of a viscous incompressible electrically conducting fluid bounded by two infinite parallel non-conducting plates in the presence of a uniform transverse magnetic field is studied on taking Hall currents into account. The relevant equations are solved analytically. The solution obtained shows that the inclusion of Hall currents gives some interesting results. It is found that the Hall currents tend to retard the primary velocity in the region near the stationary plate and accelerates the primary velocity in the region near the moving plate. It has reverse effect on the secondary velocity in the presence of Hall currents. It is observed that the induced magnetic field components are radically influenced by the Hall currents. On the other hand, the shear stresses at the moving plate decreases with an increase in the Hall parameter. It is interesting to note that both for large squared-Hartmann number and rotation parameter there exists a single-deck boundary layer in the region near the stationary plate. The boundary layer thickness increases with an increase in Hall parameter whereas it decreases with an increase in either squared-Hartmann number or rotation parameter. The asymptotic behavior of the solutions are discussed for large values of squared-Hartmann number and rotation parameter.

MHD Free and Forced Convective Flow in a Rotating Channel

A steady MHD free and forced convective viscous incompressible electrically conducting flow in a rotating channel under constant pressure gradient has been studied. An exact solution of the governing equations has been obtained in closed form. The numerical results for the velocity components, the induced magnetic field components and the temperature distribution are being presented graphically. The shear stresses and critical Grashof numbers at the lower and upper plates have been calculated. The heat transfer characteristics have also been studied on taking viscous and Joule dissipations into account. The rate of heat transfer at the lower plate increases whereas the rate of heat transfer at the upper plate decreases with an increase in either magnetic parameter or Eckert number or Grashof number.

Transient MHD Natural Convection between Two Vertical Walls Heated/Cooled Asymmetrically

transient MHD natural convection flow of a viscous incompressible electrically conducting fluid confined between vertical walls heated/cooled asymmetrically has been studied. We have considered two different cases (i) when one of the walls is stationary and (ii) when one of the walls starts to move impulsively. The governing equations have been solved analytically using the Laplace transform technique. The velocity field and temperature distribution are being presented graphically. The fluid velocity decreases for both the stationary wall as well as for impulsive motion of one of the walls with an increase in either magnetic parameter or Prandtl number. An increase in fluid temperature occurs due to an increase in temperature difference ratio. Further, the shear stress increases for both the stationary wall as well as for impulsive motion of one of the walls with an increase in either Grashof number or temperature difference ratio or time. The rate of heat transfer at the wall 0  

Diffusion-Thermo and Thermal Radiation of an Optically Thick Gray Gas in Presence of Magnetic Field and Porous Medium

Diffusion-thermo and thermal radiation effects on an unsteady magnetohydrodynamic (MHD) free convective flow past a moving infinite vertical plate with the variable temperature and concentration in the presence of transverse applied magnetic field embedded in a porous medium have been analyzed. The flow is governed due to the impulsive as well as accelerated motion of the plate. The governing equations have been solved by employing the Laplace transform technique. The influences of the pertinent parameters on the velocity field, temperature distribution, concentration of the fluid, shear stress, rate of heat and mass transfers at the plate have been presented either graphically or in tabular form.

Entropy Generation in MHD Free Convective Boundary Layer Flow Past an Inclined Flat Plate Embedded in a Porous Medium with Hall Currents

An analysis of entropy generation in an MHD boundary layer flow of a viscous incompressible electrically conducting fluid past an inclined flat plate embedded in a porous media in a rotating system with Hall currents has been presented. The governing equations describing the flow have been solved analytically. The velocity field, induced magnetic field, shear stress and bulk temperature in the boundary layer flow have been discussed with the help of graphs. The entropy generation is estimated via an analytical solution of the temperature and velocity profiles obtained from the momentum and energy equations governing the flow. The Bejan number is also obtained and discussed.

Flow Induced by Torsional Oscillations of a Disk in a Rotating Visco-Elastic Fluid

The flow due to torsional oscillations of a disk about a steady rotation in an elastico-viscous fluid which is also rotating has been analyzed. The flow is characterized by two circularly polarized waves travelling with different velocities. It is found that the depth of penetration or wave length decreases for 0 0.58