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Article
Publication date: 5 June 2017

Noreen Sher Akbar, O. Anwar Beg and Z.H. Khan

Sheet processing of magnetic nanomaterials is emerging as a new branch of smart materials’ manufacturing. The efficient production of such materials combines many physical…

Abstract

Purpose

Sheet processing of magnetic nanomaterials is emerging as a new branch of smart materials’ manufacturing. The efficient production of such materials combines many physical phenomena including magnetohydrodynamics (MHD), nanoscale, thermal and mass diffusion effects. To improve the understanding of complex inter-disciplinary transport phenomena in such systems, mathematical models provide a robust approach. Motivated by this, this study aims to develop a mathematical model for steady, laminar, MHD, incompressible nanofluid flow, heat and mass transfer from a stretching sheet.

Design/methodology/approach

This study developed a mathematical model for steady, laminar, MHD, incompressible nanofluid flow, heat and mass transfer from a stretching sheet. A uniform constant-strength magnetic field is applied transversely to the stretching flow plane. The Buongiorno nanofluid model is used to represent thermophoretic and Brownian motion effects. A non-Fourier (Cattaneo–Christov) model is used to simulate thermal conduction effects, of which the Fourier model is a special case when thermal relaxation effects are neglected.

Findings

The governing conservation equations are rendered dimensionless with suitable scaling transformations. The emerging nonlinear boundary value problem is solved with a fourth-order Runge–Kutta algorithm and also shooting quadrature. Validation is achieved with earlier non-magnetic and forced convection flow studies. The influence of key thermophysical parameters, e.g. Hartmann magnetic number, thermal Grashof number, thermal relaxation time parameter, Schmidt number, thermophoresis parameter, Prandtl number and Brownian motion number on velocity, skin friction, temperature, Nusselt number, Sherwood number and nanoparticle concentration distributions, is investigated.

Originality/value

A strong elevation in temperature accompanies an increase in Brownian motion parameter, whereas increasing magnetic parameter is found to reduce heat transfer rate at the wall (Nusselt number). Nanoparticle volume fraction is observed to be strongly suppressed with greater thermal Grashof number, Schmidt number and thermophoresis parameter, whereas it is elevated significantly with greater Brownian motion parameter. Higher temperatures are achieved with greater thermal relaxation time values, i.e. the non-Fourier model predicts greater values for temperature than the classical Fourier model.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 2 March 2015

Noreen Sher Akbar

– The purpose of this paper is to discuss free convection peristaltic flow in an asymmetric channel with nanofluid containing gyrotactic microorganism.

Abstract

Purpose

The purpose of this paper is to discuss free convection peristaltic flow in an asymmetric channel with nanofluid containing gyrotactic microorganism.

Design/methodology/approach

The governing equations for proposed model are simplified using “long wavelength and low Reynolds number approximation.” Numerical solutions have been presented for “velocity, pressure gradient, the solid volume fraction nanoparticles, temperature profile and density of motile microorganisms.” The effects of various flow parameters, i.e Hartmann number, the solid volume fraction of the nanoparticles amplitude ratio, Prandtl number, bioconvection Péclet number, bioconvection constant, bioconvection Rayleigh number are presented.

Findings

The author finds that the pressure rise increases with an increase in Hartmann number, Grashof number bioconvection, Rayleigh number and buoyancy ratio in the peristaltic pumping section.

Originality/value

The peristaltic flow nanofluid containing gyrotactic microorganism is explored in the literature for the first time.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 25 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 4 May 2012

Noreen Sher Akbar and Sohail Nadeem

The purpose of this paper is to study the effects of temperature‐dependent viscosity on the peristaltic flow of Jeffrey fluid through the gap between two coaxial horizontal tubes.

Abstract

Purpose

The purpose of this paper is to study the effects of temperature‐dependent viscosity on the peristaltic flow of Jeffrey fluid through the gap between two coaxial horizontal tubes.

Design/methodology/approach

The inner tube is maintained at a temperature T00 and the outer tube has sinusoidal wave travelling down its wall and it is exposed to temperature T1. The governing problem is simplified using longwave length and low Reynold number approximations. Regular perturbation in terms of small viscosity parameter is used to obtain the expressions for the temperature and velocity for Reynold' s models of viscosity. The numerical solution of the problem has also been computed by shooting method and an agreement of numerical solutions and analytical solutions had been presented. The expressions for pressure rise and friction force are calculated numerically.

Findings

Graphical results and trapping phenomenon are presented at the end of the paper to see the physical behaviour of different parameters.

Originality/value

The paper is a new and original work on the subject of peristaltic flows and heat transfer in Jeffrey fluid.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 22 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 3 August 2012

Noreen Sher Akbar, S. Nadeem, T. Hayat and Awatif A. Hendi

The purpose of this study is to examine the effects of heat and mass transfer on the peristaltic flow of Eyring‐Powell fluid in a diverging tube.

Abstract

Purpose

The purpose of this study is to examine the effects of heat and mass transfer on the peristaltic flow of Eyring‐Powell fluid in a diverging tube.

Design/methodology/approach

The governing equations for Eyring‐Powell are modelled in cylindrical coordinates using long wavelength and low Reynolds number approximation. The resulting nonlinear differential equations are solved for velocity, temperature and concentration profile and pressure gradient using regular perturbation technique. Also, the numerical solutions for velocity profile have been computed employing finite difference technique. A comparative study is also presented for both the solutions.

Findings

Numerical integration has been performed to get the expression of pressure rise and frictional forces. Graphical results have been presented for pressure rise, frictional forces, temperature and concentration profile for various physical parameters of interest for five considered wave forms.

Originality/value

Trapping phenomena have been discussed at the end of the article.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 22 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

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