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1

Velocity and Temperature Distributions between Parallel Porous Plates with the Hall Effect and Variable Properties Under Exponential Decaying Pressure Gradient

Attia H. A., Abdeen M. A. M.

Engineering Transactions

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2012

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Vol. 60, iss. 2

139-139

EN

The time varying hydromagnetic flow between two infinite parallel porous plates is studied with heat transfer considering the Hall effect and temperature dependent physical properties. An exponential decaying pressure gradient is imposed in the axial direction and an external uniform magnetic field as well as a uniform suction and injection are applied perpendicular to the horizontal plates. A numerical solution for the governing non-linear coupled set of equations of motion and the energy equation is adopted. The effects of the Hall current and the temperature dependent viscosity and thermal conductivity on both the velocity and temperature distributions are investigated.

2

A characterization theorem in hydromagnetic double-diffusive convection coupled with cross diffusions

Mohan H.

Studia Geotechnica et Mechanica

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2010

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Vol. 32, nr 2

23-39

EN

In the present paper, the governing equations of hydromagnetic double-diffusive convection problem of Veronis' type coupled with cross diffusion are linearized by the construction of a proper transformation and the relationship between various energies is established. The analysis made shows that total kinetic energy associated with a disturbance is greater than the sum of its total magnetic and concentration energies in the parameter regime. The result is valid for quite general boundary conditions.

3

Finite element solutions for two-phase magneto-heat transfer in a particle-suspension through a non-Darcian porous channel with heat source and buoyancy effects

Bhargava R., Rawat S., Takhar H. S., Beg T. A., Anwar Beg o.

International Journal of Applied Mechanics and Engineering

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2008

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Vol. 13, no 2

325-357

EN

We consider the steady, laminar natural convection heat transfer of a particulate suspension in an electrically-conducting fluid through a two-dimensional channel containing a non-Darcian porous material in the presence of a transverse magnetic field. The transport equations for both fluid and particle phases are formulated using a two-phase continuum model and a heat source term is included which simulates either absorption or generation. A set of transformations are implemented to reduce the partial differential equations for momentum and energy conservation (for both phases) from a two-dimensional coordinate system to a one-dimensional system. Finite element solutions are obtained for the transformed model. A comprehensive parametric study of the effects of the heat source parameter (E), Prandtl number (Pr), Grashof number (Gr), momentum inverse Stokes number (Skm), Darcy number (Da), Forchheimer number (Fs), particle loading parameter (PL), buoyancy parameter (B), Hartmann number (Ha), temperature inverse Stokes number (SkT), viscosity ratio [...], specific heat ratio [...], dimensionless particle-phase wall slip parameter [...] on the dimensionless fluid phase velocity (U), dimensionless particle phase velocity ( ), dimensionless fluid phase temperature [...] and the dimensionless temperature of particle phase [...] are presented graphically. In addition, we also describe numerical solutions for several special cases of the model, for example, the inviscid hydromagnetic two phase non-Darcian free convection, heat transfer [...], forced convection case (GrŽ0) etc. Fluid phase velocities are found to be strongly reduced by the magnetic field, Darcian drag and also Forchheimer drag; a lesser reduction is observed for the particle phase velocity field. The Prandtl number is shown to depress both the fluid temperature and particle phase temperature in the left hand side of the channel but to boost both temperatures at the right hand side of the channel [...]. The inverse momentum Stokes number is seen to reduce fluid phase velocities and increase particle phase velocities. The influence of other thermophysical parameters is discussed in detail and computations compared with previous studies. The model finds applications in MHD plasma accelerators, astrophysical flows, geophysics, geothermics and industrial materials processing.

4

Influence of fluctuating surface temperature and velocity on unsteady MHD natural convection adjacent to a permeable surface immersed in porous medium with heat absorption

Chaudhary R. C., Jain P.

Journal of Technical Physics

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2006

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Vol. 47, no 4

239-254

EN

The present study will focus on the combined effect of oscillating surface temperature and fluctuating surface velocity, under the action of uniform transverse magnetic field applied normally to the plane and internal heat absorption effect. The wall temperature is oscillating periodically in time about a non-zero constant mean temperature. The plate is permeable enabling possible fluid withdrawal. The nonlinear coupled partial differential equations governing the flow, representing the constitutive laws, are transformed into a system of ordinary differential equations by the perturbation technique. A parametric study of all the parameters involved is conducted and a representative set of numerical results concerning the velocity and temperature profiles, as well as the amplitude and phase of skin friction and Nusselt number, is illustrated graphically to show typical trends of the solutions.

5

On electrically conducting couple-stress fluid heated from below in porous medium in presence of uniform horizontal magnetic field

Sharma R. C., Sharma S.

International Journal of Applied Mechanics and Engineering

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2001

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Vol. 6, no 2

251-263

EN

A layer of electrically conducting couple-stress fluid heated from below in porous medium is considered in the presence of uniform horizontal magnetic field. The medium permeability hastens the onset of convection whereas the magnetic field and couple-stress postpone the onset of convection, for the case of stationary convection. The oscillatory modes are introduced by the magnetic field which were not present in the absence of the magnetic field. The overstable case has been considered and a sufficient condition for the non-existence of overstability is obtained.