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1

Effect of chemical reaction on mixed convective nanofluid flow on a vertical plate with uniform heat and mass fluxes

Mondal H., Goqo S. P., Sibanda P., De P.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 2

329--342

EN

The purpose of this paper is to consider a two dimensional free convective flow of a nanofluid due to the combined effects of thermal and mass diffusion in the presence of a chemical reaction of first order. The objective of the present investigation is to analyze the free convective flow in the presence of prescribed wall heat flux and mass flux condition. The governing equations of the linear momentum, energy equation and concentration are obtained in a dimensionless form by introducing a suitable group of similarity transformations. The transformed coupled non-linear ordinary differential equations are solved numerically by using appropriate boundary conditions for the various values of physical parameters. Computations are performed for a wide range of values of the various governing flow parameters of the velocity, temperature and species concentration profiles and results are presented graphically. Numerical results for the skin friction coefficient and local Nusselt number are also presented and analyzed in detail. The obtained results are compared with previously published work and are found to be in excellent agreement. The results are a very useful source of information for researchers on the subject of a free convective flow of a nanofluid. This paper illustrates chemical reaction effects on free convective flow of a nanofluid from a vertical plate with uniform heat and mass fluxes.

2

An asymptotic analysis of convection in boundary layer flows in the presence of a chemical reaction

Shateyi S., Sibanda P., Motsa S. S.

Archives of Mechanics

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2005

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Vol. 57, nr 1

25--41

EN

In this study we investigate the stability of two-dimensional disturbances imposed on a boundary layer flow over a semi-infinite flat plate in the presence of a reacting chemical species. Species concentration levels are assumed to be small, what is typical for many processes in water and in atmospheric air. We exploit the multi-deck structure of the flow in the limit of large Reynolds numbers to analyze asymptotically the perturbed flow. The neutral eigenrelations are obtained implicitly and limiting cases for large buoyancy and reaction kinematics are investigated. The results show some interesting effects of the Damkohler number on the wave number and wave speed of the disturbed flow.

3

Linear stability of two-dimensional flow to three-dimensional perturbations in a channel with a flexible wall

Sibanda P., Motsa S. S., Shateyi S.

Archives of Mechanics

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2004

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Vol. 56, nr 4

293-311

EN

In this paper we investigate the effects of three-dimensional disturbance waves on the stability of a two-dimensional channel flow with one compliant surface. The study exploits the multideck structure of the flow in the limit of large Reynolds numbers to make an asymptotic analysis of the flow and to derive linear neutral stability results. The study shows that for a flow over flexible surfaces, three-dimensional disturbances may be more unstable than two-dimensional modes for a given set of wall properties.

4

The biomechanics of atherosclerosis development

Makinde O. D., Acho T. M., Sibanda P., Lungu E. M.

Computer Assisted Mechanics and Engineering Sciences

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2003

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Vol. 10, No. 1

23-31

EN

In this paper, we investigate the bio-mechanics of atherosclerosis development in human physiology. Blood is modelled as an incompressible fluid of variable viscosity flowing in a slightly diverging channel (i.e. large artery) of small aspect ratio [1]. The hypothetical viewpoint in this work is the existence of relationship between the atherosclerosis development, blood viscosity, flow separation and turning points in the flow field. The problem is tackled by asymptotic approximation and the graphical results are discussed quantitatively.

5

The effect of heating/cooling on the upper-branch stability of boundary layer flows over a compliant boundary

Motsa S. S., Gajjar J. S., Sibanda P.

Computer Assisted Mechanics and Engineering Sciences

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2002

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Vol. 9, No. 2

163-181

EN

We investigate the evolution of Tollmien-Schlichting waves in boundary layers in the presence of moderate buoyancy arising from the heating or cooling of a compliant wall. We exploit the multi-deck structure of the flow in the limit of large Reynolds numbers to make an asymptotic analysis of the pertubed flow, along the upper-branch of the neutral stability curve, to derive linear neutral results. These results are discussed and are compared to rigid wall results. Also, a brief parametric study, based on the linear neutral results, is presented and the results are discussed.

6

On solution driven flow and heat transfer in a pipe filled with porous media

Makinde O. D., Sibanda P.

Computer Assisted Mechanics and Engineering Sciences

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1998

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Vol. 5, nr 4

389-398

EN

The axisymmetric flow of a viscous fluid and heat transfer in a pipe filled with porous media driven by suction at the pipe wall is examined. For low suction Reynolds number flow, asymptotic solutions are developed. Using MAPLE, the solution series is extended and a bifurcation study is performed. Our results show that a decrease in the permeability of porous media may reduce the magnitude of heat transfer across the wall. The absence of real solutions of the given type between two turning points is also noticed and this gap of no solution disappears as the permeability of the porous media decreases.