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1

Effect of thermal stratification on MHD free convection flow of a micropolar fluid over a stretching surface

Mahdy A.

International Journal of Applied Mechanics and Engineering

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2011

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Vol. 16, no 3

763-773

EN

This paper analyses the flow and heat transfer characteristics of free convection in the boundary layer flow of a micropolar fluid past a stretching surface with magnetic field, thermal stratification, and heat generation or absorption effects. A similarity transformation was employed to change the governing momentum, angular momentum, and energy partial differential equations into ordinary ones. Then the numerical solution of the problem is derived using the Runge-Kutta Gill method. The sheet is linearly stretched in the presence of a uniform free stream of constant velocity. Numerical results are shown in a tabular form and graphically for the velocity, angular velocity, and temperature as well as the skin-friction and wall heat transfer rate and discussed for various physical parametric values.

2

Non-Darcy mixed convection heat and mass transfer from a vertical wavy surface in porous media

Mohamed R. A., Mahdy A.

International Journal of Applied Mechanics and Engineering

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2009

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Vol. 14, no 3

813-827

EN

This paper reports a study of mixed convection heat and mass transfer from a vertical wavy surface embedded in a homogeneous fluid-saturated porous medium using the Forchheimer flow model. The buoyancy effect is due to the variation of temperature and concentration across the boundary layer. We consider the boundary-layer regime where the Péclet number is very lager, […]. Appropriate transformations are employed to transform the governing partial differential equations into the boundary layer equations. The transformed equations have been solved numerically employing the Runge Kutta integration scheme with the shooting technique. Extensive computations are presented for a wide range of wave amplitudes the mixed convection parameter inertial parameter […] the Lewis number and the buoyancy ratio The numerical results illustrating the effects of all previously involved parameters on the velocity profiles[…] temperature […] mass […] the local Nusselt number […] and the local Sherwood number […] are presented and discussed in detail.

3

Non-Darcy non-Newtonian free convection flow over a vertical plate under the influence of Soret and Dufour effect

Mahdy A.

International Journal of Applied Mechanics and Engineering

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2008

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Vol. 13, no 4

1125-1132

EN

A non-similar boundary layer analysis is carried out to study the effect of Soret and Dufour on heat and mass transfer for a power-law, non-Newtonian fluid. Thermo-diffusion implies that the heat transfer is induced by concentration gradient, and thermo-diffusion implies that the mass diffusion is induced by thermal gradient. The resultant governing boundary-layer equations, highly non-linear and a coupled form of partial differential equations have been solved by employing a numerical, Runge-Kutta fourth order technique with a modified version of the Newton-Raphson shooting method. A parametric study of all parameters involved is conducted, and a representative of the results for the velocity, temperature, concentration profiles as well as the Nusselt and the Sherwood numbers are illustrated graphically to elucidate interesting features of the solutions.

4

Non-Darcy natural convection flow along a vertical wavy plate embedded in a Non-Newtonian fluid saturated porous medium

Hady F. M., Mohamed R. A., Mahdy A.

International Journal of Applied Mechanics and Engineering

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2008

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Vol. 13, no 1

91-100

EN

The present analysis investigates the non-Darcian free convection of a non-Newtonian fluid from a vertical sinusoidal wavy plate embedded in a homogenous porous medium with constant wall temperature. After a suitable coordinate transformation to reduce the complexity of the goveming boundary-layer equations, the resulting nonlinear, coupled differential equations were solved with the Runge-Kutta integration scheme. The Darcy-Rayleigh number is considered to be very large. The power-law model is used for non-Newtonian fluids with exponent n < 1 for pseudoplastic fluids; n= 1 for Newtonian fluids and n > 1 for dilatant fluids. The effects of the Grashof number Gr * , the wavy geometry, and the non-Newtonian nature of the fluids on the local and global rates of heat transfer are discussed. An increase in the power-law index leads to a greater fluctuation of the local Nusselt number and increasses the global rate of heat transfer. An increase in the Grashof num ber leads to a smaller fluctuation of the local heat transfer and increasing the boundary layer thickness, hence decreasing the global rate ofheat transfer.

5

MHD boundary layer flow and heat transfer over a continuous moving wavy surface in porous media

Hady F. M., Mohamed R. A., Mahdy A.

International Journal of Applied Mechanics and Engineering

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2007

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Vol. 12, no 2

353-368

EN

Non-similarity solutions for the boundary layer flow and heat transfer on a continuous moving wavy porous surface immersed in a quiescent electrically conducting fluid-saturated porous medium with a constant transverse magnetic field are obtained. Results for the velocity [...] and temperature O fields are presented, as well as the results for the skin-friction coefficient, C f and the local Nusselt number, Nu . These numerical results are given for different values of the amplitude of the wavy surface a, magnetic parameter M, the inverse Darcy number Da -1 , and Prandtl number Pr, then these results are illustrated graphically.