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Unsteady MHD heat transfer in Couette flow of water at 4°c in a rotating system with ramped temperature via finite element method

Reddy G. J., Raju R. S., Rao J. A., Gorla R. S. R.

International Journal of Applied Mechanics and Engineering

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2017

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Vol. 22, no. 1

145--161

EN

An unsteady magnetohydromagnetic natural convection on the Couette flow of electrically conducting water at 4°C (Pr = 11.40) in a rotating system has been considered. A Finite Element Method (FEM) was employed to find the numerical solutions of the dimensionless governing coupled boundary layer partial differential equations. The primary velocity, secondary velocity and temperature of water at 4°C as well as shear stresses and rate of heat transfer have been obtained for both ramped temperature and isothermal plates. The results are independent of the mesh (grid) size and the present numerical solutions through the Finite Element Method (FEM) are in good agreement with the existing analytical solutions by the Laplace Transform Technique (LTT). These are shown in tabular and graphical forms.

2

Numerical solutions by EFGM of MHD convective fluid flow past a vertical plate immersed in a porous medium in the presence of cross diffusion effects via biot number and convective boundary condition

Raju R. S., Reddy B. M., Rashidi M. M., Gorla R. S. R.

International Journal of Applied Mechanics and Engineering

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2017

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Vol. 22, no. 3

613--636

EN

In this investigation, the numerical results of a mixed convective MHD chemically reacting flow past a vertical plate embedded in a porous medium are presented in the presence of cross diffusion effects and convective boundary condition. Instead of the commonly used conditions of constant surface temperature or constant heat flux, a convective boundary condition is employed which makes this study unique and the results more realistic and practically useful. The momentum, energy, and concentration equations derived as coupled second-order, ordinary differential equations are solved numerically using a highly accurate and thoroughly tested element free Galerkin method (EFGM). The effects of the Soret number, Dufour number, Grashof number for heat and mass transfer, the viscous dissipation parameter, Schmidt number, chemical reaction parameter, permeability parameter and Biot number on the dimensionless velocity, temperature and concentration profiles are presented graphically. In addition, numerical results for the local skin-friction coefficient, the local Nusselt number, and the local Sherwood number are discussed through tabular forms. The discussion focuses on the physical interpretation of the results as well as their comparison with the results of previous studies.

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Transfer effects on an unsteady MHD mixed convective flow past a vertical plate with chemical reaction

Raju R. S.

Engineering Transactions

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2017

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Vol. 65, iss. 2

221--249

EN

An attempt is made to study the effects of chemical reaction and combined buoyancy effects on an unsteady MHD mixed convective flow along an infinite vertical porous plate in the presence of hall current. A uniform magnetic field is applied in a direction normal to the porous plate. The governing coupled non-linear partial differential equations are solved using an efficient Galerkin finite element method. With the help of graphs, the effects of the various important parameters entering into the problem on the velocity, temperature, and concentration fields within the boundary layer are discussed. Also the effects of the pertinent parameters on the skin-friction coefficient and rates of heat and mass transfer in terms of the Nusselt number and Sherwood number are presented numerically in a tabular form. The results obtained show that the velocity, temperature, and concentration fields are appreciably influenced by the presence of chemical reaction, hall current, heat, and mass transfer. It is observed that the effect of Schmidt number and chemical reaction parameter is to decrease the velocity and concentration profiles in the boundary layer while the velocity profiles are increasing with increasing of hall parameter, Grashof numbers for heat and mass transfer. There is also considerable effect of hall current and chemical reaction on skin-friction coefficient and Nusselt number. In the present analysis various comparisons with previously published work are performed and the results are found to be in a good agreement.