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1

Combined thermal and diffusion buoyancy effects in micropolar fluids

Mansour M. A., Mohammadein A. A., El Kabeir S. M., Gorla R. S. R.

International Journal of Applied Mechanics and Engineering

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2001

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Vol. 6, no 2

551-572

EN

A regular perturbation analysis is presented for the laminar natural convection flows of micropolar fluids with temperature dependent viscosity: a freely-rising plane plume, the flow above a horizontal line source on an adiabatic surface (a plan wall plume) and the flow adjacent to a vertical uniform flux surface. While these flows have well-known power-law similarity solutions when the fluid viscosity is taken to be constant, they are non-similar when the viscosity is considered to be a function of temperature. A flow adjacent to a vertical isothermal surface is also analyzed for comparison in order to estimate the extent of validity of the perturbation analysis. The formulation used here provides a unified treatment of variable viscosity effects on those four flows. Computed first-order perturbation quantities are presented for all four flows. The velocity, microrotation distribution, temperature and concentration profiles are shown. Numerical results are presented for the local Nusselt number and Sherwood number, wall shear stress and wall couple stress.

2

Heat transfer from a stretching surface in a micropolar fluid

El-Hakiem M. A., Mohammadein A. A., Mansour M. A., Gorla R. S. R.

Applied Mechanics and Engineering

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1999

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Vol. 4, no 1

25-34

EN

The theory of micropolar fluids due to Eringen is used to formulate a set of boundary layer equations for the heat transfer from an arbitrarily stretching surface with non-uniform surface temperature. A two dimensional similarity solution to the governing momentum, angular momentum and energy equations is presented. The effects of the boundary conditions used for the microrotation term are discussed. Numerical data for the friction factor and Nusselt number has been shown graphically for a range of values of the material properties.

3

Variable viscosity effects on natural convection in micropolar fluid at an axisymetric stagnation point

Mohammadein A. A., El-Kabeir S. M., Gorla R. S. R.

Applied Mechanics and Engineering

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1998

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Vol. 3, no 4

539-552

EN

A three-dimensional boundary layer solution is presented for the natural convection in a micropolar fluid in the vicinity of an axisymmetric stagnation point on heated vertical surfaces. The effects of variable viscosity are included. The governing equations for the velocity, microrotation and temperature fields are solved numerically.

4

Hiemenz flow of a micropolar fluid in hydromagnetics

Mohammadein A. A., El Kabeir S. M., El-Hakiem M. A., Gorla R. S. R.

Applied Mechanics and Engineering

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1998

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Vol. 3, no 3

367-376

EN

A boundary layer analysis has been presented for Hiemenz flow in hydromagnetics of a micropolar incompressible, viscous, electrically conducting fluid impinging normal to a plane in the presence of a transverse magnetic field. Numerical solutions are given for the governing momentum and angular momentum equations. An approximate solution is given which is simple and yet sufficiently accurate for the entire range of values of Harman number investigated. A discussion has been provided for the effect micropolar parameters on Hiemenz flow in hydromagnetics.

5

Boundary layer heat transfer in a micropolar fluid over a flat plate with vectored surface mass transfer

Hassanien I. A., Gorla R. S. R., Mohammadein A. A.

Applied Mechanics and Engineering

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1998

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Vol. 3, no 1

25-37

EN

An analysis is presented for the heat transfer in a micropolar fluid boundary layer over a flat plate with uniformly distributed vectored surface mass transfer. Numerical solutions for the governing nonsimilar boundary layer equations are presented for a range of values of the material properties and Prandtl number of the fluid. The results indicate that the micropolar fluids display a reduction in drag as well as heat transfer rate when compared with Newtonian fluids.