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Uddin M.J.,Universiti Sains Malaysia | Beg O.A.,Gort Engovation Research Propulsion | Aziz A.,Gonzaga University | Ismail A.I.Md.,Universiti Sains Malaysia
Mathematical Problems in Engineering | Year: 2015

A theoretical study of two-dimensional magnetohydrodynamics viscous incompressible free convective boundary layer flow of an electrically conducting, chemically reacting nanofluid from a convectively heated permeable vertical surface is presented. Scaling group of transformations is used in the governing equations and the boundary conditions to determine absolute invariants. A third-order ordinary differential equation which corresponds to momentum conservation and two second-order ordinary differential equations which correspond to energy and nanoparticle volume fraction (species) conservation are derived. Our (group) analysis indicates that, for the similarity solution, the convective heat transfer coefficient and mass transfer velocity are proportional to x-1/4 whilst the reaction rate is proportional to x-1/2, where x is the axial distance from the leading edge of the plate. The effects of the relevant controlling parameters on the dimensionless velocity, temperature, and nanoparticle volume fraction are examined. The accuracy of the technique we have used was tested by performing comparisons with the results of published work and the results were found to be in good agreement. The present computations indicate that the flow is accelerated and temperature enhanced whereas nanoparticle volume fractions are decreased with increasing order of chemical reaction. Furthermore the flow is strongly decelerated, whereas the nanoparticle volume fraction and temperature are enhanced with increasing magnetic field parameter. Increasing convection-conduction parameter increases velocity and temperatures but has a weak influence on nanoparticle volume fraction distribution. The present study demonstrates the thermal enhancement achieved with nanofluids and also magnetic fields and is of relevance to nanomaterials processing. © 2015 Md. Jashim Uddin et al. Source

Uddin M.J.,Bangladesh American International University | Uddin M.J.,Universiti Sains Malaysia | Kabir M.N.,Universiti Malaysia Pahang | Beg O.A.,Gort Engovation Research Propulsion
International Journal of Heat and Mass Transfer | Year: 2016

The effects of Stefan blowing and the velocity, thermal and solutal slips on bioconvection nanofluid flow over a horizontal moving plate in the presence of passively controlled boundary conditions are numerically investigated. The Lie group transformation is introduced to seek similarity solutions of such nano-bioconvection flows for the first time. The reduced governing ordinary differential equations are then numerically solved with Matlab nonlinear equation solver fsolve and ODE solver ode15s. The influences of Stefan blowing, the velocity, thermal and solutal slips, the bioconvection Lewis number, the Lewis number, the velocity, the bioconvection Peclet number and Brownian motion on the dimensionless velocity, temperature, nanoparticle volume fraction, microorganism concentration, the distribution of the density of motile microorganisms, the local skin friction coefficient, the local Nusselt number and the local wall mass flux are analyzed and discussed. The study is relevant to novel microbial fuel cell technologies combining the nanofluid with bioconvection phenomena. © 2015 Elsevier Ltd. All rights reserved. Source

Tripathi D.,National Institute of Technology Delhi | Anwar Beg O.,Gort Engovation Research Propulsion
Mathematical Biosciences | Year: 2014

A mathematical study of the peristaltic flow of complex rheological viscoelastic fluids using the generalized fractional Burgers' model through a non-uniform channel is presented. This model is designed to study the movement of chyme and undigested chyme (biophysical waste materials) through the small intestine to the large intestine. To simulate blockages and impedance of debris generated by cell shedding, infections, adhesions on the wall and undigested material, a drag force porous media model is utilized. This effectively mimicks resistance to chyme percolation generated by solid matrix particles in the regime. The conduit geometry is mathematically simulated as a sinusoidal propagation with linear increment in shape of the bolus along the length of channel. A modified Darcy-Brinkman model is employed to simulate the generalized flows through isotropic, homogenous porous media, a simplified but physically robust approximation to actual clinical situations. To model the rheological properties of chyme, a viscoelastic Burgers' fluid formulation is adopted. The governing equations are simplified by assuming long wavelength and low Reynolds number approximations. Numerical and approximate analytical solutions are obtained with two semi-numerical techniques, namely the homotopy perturbation method and the variational iteration method. Visualization of the results is achieved with Mathematica software. The influence of the dominant hydromechanical and geometric parameters such as fractional viscoelastic parameters, wave number, non-uniformity constant, permeability parameter, and material constants on the peristaltic flow characteristics are depicted graphically. © 2013 Elsevier Inc. Source

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