Unsteady hydromagnetic couette flow due to ramped motion of one of the porous plates

Abstract An unsteady flow formation in Couette motion of an electrically conducting fluid subject to transverse magnetic field has been analyzed in the presence of suction/injection through the porous plates when one of the porous plates is in ramped motion. It is assumed that the porous plates are uniformly permeable and the fluid is entering the flow region through one of the porous plates at same rate as it is leaving through the other porous plate. The resulting boundary value problem has been solved exactly under the assumption of a negligible induced magnetic field, external electric field and pressure gradient. Unified closed form expressions for the velocity field and skin-friction corresponding to the case of a magnetic field fixed relative to the fluid or to the moving porous plate have been presented. In order to highlight the impact of the ramp motion of the porous plate on the fluid flow, it has also been compared with Couette flow between porous plates when one of the porous plates has been set into an impulsive motion.

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Hydromagnetic Flow Over a Conducting Thick Porous Plate With Hall Effects

Journal of Applied Mechanics ◽

10.1115/1.3424508 ◽

1979 ◽

Vol 46 (1) ◽

pp. 220-223

Author(s):

S. Chhatait ◽

K. K. Mandal

Keyword(s):

Magnetic Field ◽

Hall Current ◽

Porous Plate ◽

Mhd Flow ◽

Transverse Magnetic ◽

Secondary Flows ◽

Magnetic Field Effects ◽

Induced Magnetic Field ◽

Electrically Conducting ◽

Wall Conductivity

MHD flow of an incompressible viscous electrically conducting fluid due to a uniform stream passing over a thick, porous conducting flat plate subjected to a uniform suction at the plate under the influence of uniform transverse magnetic field has been studied taking into account the effect of Hall current. Induced magnetic field has been taken into consideration and exact solutions have been obtained for primary and secondary flows and induced magnetic field. Effects of different parameters have been illustrated using graphs. It has also been pointed out that when the magnetic Prandtl number is very small effects of Hall current, wall conductivity, and thickness of the plate are all negligible.

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Non-Newtonian-flow formation in Couette motion in magnetohydrodynamics with time-varying suction

Canadian Journal of Physics ◽

10.1139/p91-012 ◽

1991 ◽

Vol 69 (2) ◽

pp. 75-82 ◽

Cited By ~ 3

Author(s):

Nabil T. Eldabe ◽

Ahmed A. A. Hassan

Keyword(s):

Magnetic Field ◽

Transverse Magnetic Field ◽

Incompressible Flow ◽

Transverse Magnetic ◽

Time Varying ◽

Induced Magnetic Field ◽

Newtonian Flow ◽

Electrically Conducting ◽

Moving Wall ◽

Flow Formation

This paper is an analysis of an incompressible flow of electrically conducting non-Newtonian fluid between two infinite parallel walls one of them moving with a uniform velocity under the action of a transverse magnetic field. The moving wall is subjected to a suction whose magnitude oscillates with respect to time over a constant mean. In our analysis we are taking into account the induced magnetic field; a matter that is neglected by the majority of the previous work. The main results show that the effect of the viscoelasticity of the fluid is to decrease both the flow and the induced magnetic field.

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