Engineering Transactions, 42, 4, pp. 377-391, 1994

Magnetohydrodymanic Natural Convection Flows Resulting From the Combined Buoyancy Effects of Thermal and Mass Diffusion

A.A. Samaan
Department of Mathematics, Faculty of Girls, Ain Shams University, Cairo
Egypt

F.N. Ibrahim
Department of Mathematics, Faculty of Sciences, Ain Shams University, Cairo
Egypt

This paper presents a study of laminar doubly diffusive free convection flows of a viscoelastic fluid past an oscillating vertical plate in the presence of a transverse magnetic field. The two buoyant mechanisms are the thermal diffusion and species diffusion. The governing conservation equations of momentum, energy and concentration are nondimensionalized and solved analytically. Effects of Pr (Prandtl number), Sc (Schmidt number), Gr (Grashof number), Gm (modified Grashof number), M (magnetic number), ω (frequency parameter) and k (viscoelastic parameter) upon the velocity field, the shear stress on the plate, the temperature field and the concentration field are discussed. The results show many interesting aspects of the complex interaction of the two buoyant mechanisms.

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References

D. ANGIRASA and J. SRINIVASAN, Natural convection flows due to the combined buoyancy of heat and mass diffusion in a thermally stratified medium, ASME J. Heat Transfer, 111, 657-663, 1989.

D.W. BEARD and K. WALTERS, Elastic-viscous boundary-layer flow. Part 1. Two­dimensional flow near a stagnation point, Proc. Cambridge Phil. Soc., 601 667-674, 1964.

S.S. CHAWLA, Magneto hydrodynamic unsteady free convection, Z. Angew. Math. Mech., 47, 499, 1967.

C.C. CHEN and R. EICHHORN, Natural convection from a vertical surface to a thermally stratified fluid, ASME J. Heat Transfer, 98, 446-451, 1976.

E.M.A. ELBASHBESHY and F.N. IBRAHIM, Steady free convection flow with a variable viscosity and thermal diffusivity along a vertical plate, Accepted for publication in J. Phys. D: Appl. Phys., 1993.

B. GEBHART and L. PERA, The nature of vertical natural convection flows resulting from the combined buoyancy effects of thermal and mass diffusion, Int. J. Heat Mass Transfer, 14, 2025-2050, 1971.

A.S. GUPTA, Steady and transient free convection of an electrically conducting fluid from a vertical plate in the presence of a magnetic field, Appl. Scient. Pes., A9, 319, 1960.

F.N. IBRAHIM, Magnetohydrodynamic unsteady free convection flow of a viscoelastic fluid along a vertical plate, Engng. Trans., 39, 1, 111-121, 1991.

S.P. MISHRA and P. MOHAPATRA, Magnetohydrodynamic unsteady free convection flow past a vertical porous plate, Indian J. Pure and Appl. Math., 6, 8, 901-917, 1975.

S. OSTRACH, Natural convection with combined driving forces, Physico-Chemical Hydrodynamics, 1, 233-247, 1980.

V.M. SOUNDALGEKAR, Unsteady MHD free convection flow past an infinite vertical flat plate with variable suction, Indian J. Pure and Appl. Math., 3, 426, 1972.




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