Unsteady magnetohydrodynamic oscillatory flow of viscoelastic fluids in a porous channel with heat and mass transfer

In this paper, we analyze the effects of slip condition on the unsteady magnetohydrodynamic (MHD) flow of incompressible viscoelastic fluids in a porous channel under the influence of transverse magnetic field and Hall current with heat and mass transfer. The channel flow is induced due to external pressure gradient of oscillatory form. The governing equations for the velocity field, temperature and concentration distributions, are solved using perturbation technique. We present the results for skin friction, Nusselt number and Sherwood number. The numerical results are also computed for skin friction in tabular form. The effects of various indispensable flow parameters are displayed using several graphs. The numerical results show the effects of the physical parameters on the fluid flow as well as on heat and mass transfer and skin friction. The solutions for Newtonian fluids can be obtained as a limiting case from our general solutions when the viscoelastic parameter is zero. © 2012 The Physical Society of Japan

A note on new exact solutions for some unsteady flows of brinkman-type fluids over a plane wall

Flows of a Brinkman fluid due to a plane boundary moving in its plane are studied using Laplace transform. The solutions that have been obtained for the velocity are presented in simple forms in terms of the complementary error function erfc(·). They satisfy all imposed initial and boundary conditions and can easily be reduced to the similar solutions for Newtonian fluids

MHD free convection flow in a porous medium with thermal diffusion and ramped wall temperature

An exact analysis is presented to study the unsteady magnetohydrodynamic flow past an impulsively started vertical plate embedded in a porous medium in the presence of thermal diffusion and ramped wall temperature at the plate. The analytical expressions for velocity, temperature and concentration fields are obtained using the Laplace transform technique. The results for skin friction, Nusselt number and Sherwood number are also developed. The analytical results are displayed graphically and discussed

Unsteady magnetohydrodynamic free convection flow of a second grade fluid in a porous medium with ramped wall temperature

Magnetic field influence on unsteady free convection flow of a second grade fluid near an infinite vertical flat plate with ramped wall temperature embedded in a porous medium is studied. It has been observed that magnitude of velocity as well as skin friction in case of ramped temperature is quite less than the isothermal temperature. Some special cases namely: (i) second grade fluid in the absence of magnetic field and porous medium and (ii) Newtonian fluid in the presence of magnetic field and porous medium, performing the same motion are obtained. Finally, the influence of various parameters is graphically shown

Radiation and porosity effects on the magnetohydrodynamic flow past an oscillating vertical plate with uniform heat flux

Magnetohydrodynamic free convection flow of an incompressible viscous fluid past an infinite vertical oscillating plate with uniform heat flux in a porous medium is studied. Exact dimensionless solutions of momentum and energy equations, under Boussinesq approximation, are obtained using Laplace transforms. They satisfy all imposed initial and boundary conditions and reduce to known solutions from the literature as special cases. Finally, the influence of different parameters like thermal radiation parameter, Grashof number, Prandtl number, and time on velocity, temperature, and skin friction is shown by graphs

Hydromagnetic rotating flow in a porous medium with slip condition and hall current

The slip effect on hydromagnetic rotating flow of viscous fluid through a porous space is investigated.The fluid is electrically conducting with the consideration of Hall current. The entire system rotatesabout the axis normal to a porousplate of uniform suction or injection with uniform angular velocity.The closed form solution is obtained using Laplace transform technique. The analytical expression forskin friction is evaluated. The graphical results are displayed to see the effects of various embeddedflow parameters such as magnetic parameterM, permeability parameterK, Hall parameterm,rotation parameter, suction or injection parameterS, slip parameterand dimensionless time.Itis found that the magnetic field and slip parameter decrease the velocity magnitude whereaspermeability and Hall parameters increase it. The slipand magnetic field play an important role inretarding the growth of both the primary and secondary flows, whereas Hall parameter enhances theflow

Conjugate effects of heat and mass transfer on MHD free convection flow over an inclined plate embedded in a porous medium.

The aim of this study is to present an exact analysis of combined effects of radiation and chemical reaction on the magnetohydrodynamic (MHD) free convection flow of an electrically conducting incompressible viscous fluid over an inclined plate embedded in a porous medium. The impulsively started plate with variable temperature and mass diffusion is considered. The dimensionless momentum equation coupled with the energy and mass diffusion equations are analytically solved using the Laplace transform method. Expressions for velocity, temperature and concentration fields are obtained. They satisfy all imposed initial and boundary conditions and can be reduced, as special cases, to some known solutions from the literature. Expressions for skin friction, Nusselt number and Sherwood number are also obtained. Finally, the effects of pertinent parameters on velocity, temperature and concentration profiles are graphically displayed whereas the variations in skin friction, Nusselt number and Sherwood number are shown through tables

Comparison of skin friction <i>τ</i> with Ziyauddin and Kumar [38].

<p>Comparison of skin friction <i>τ</i> with Ziyauddin and Kumar <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0065223#pone.0065223-Jingchun1" target="_blank">[38]</a>.</p

Velocity profiles for different values of and when , Gr, and .

<p>Velocity profiles for different values of and when , Gr, and .</p