The influence of temperature-dependent fluid properties on flow and heat transfer of an electrically conducting fluid over a stretching sheet with variable thickness in the presence of a transverse magnetic field is analyzed. Using similarity transformations, the governing coupled non-linear partial differential equations (momentum and energy equations) are transformed into a system of coupled non-linear ordinary differential equations and are solved numerically by Keller-box method. For increasing values of the wall thickness parameter, the analysis reveals quite interesting flow and heat transfer patterns. The effects of the temperature dependent viscosity, the wall velocity power index, the thermal conductivity, the wall temperature parameter and the Prandtl number on the flow and temperature fields are presented. The obtained numerical results are compared with the available results in the literature for some special cases and are found to be in excellent agreement. The skin friction and the wall temperature gradient are presented for different values of the physical parameters and the salient features are analyzed.

The present study is devoted to electromagnetohydrodynamic (EMHD) flow and heat transfer characteristics of nanofluid inside a parallel plate microchannel. The nanofluid is actuated by Lorentz force which is originated from the interaction of applied electrical field and perpendicular magnetic field. A fully developed assumption with uniform flux at the surface is considered in the analysis, and the influences of viscous dissipation as well as Joule heating are also taken into account. The analytical solutions for velocity and temperature are derived. Moreover, the Nusselt number variations are examined. The results show that the Hartmann number, the dimensionless parameter S and the nanoparticls volume fraction have significant influences on flow and temperature of nanofluid. As Hartmann number increasing, the Nusselt number improves and similar trend can be observed with the augment of nanoparticls volume fraction. A diminishment of heat transfer performance can be seen with increase of the Joule parameter and Brinkman number, while an enhancement in heat transfer can be witnessed with increase of nanoparticls volume fraction.

This paper investigates the laminar boundary layer flow of nanofluid induced by a radially stretching sheet. Nanofluid model exhibiting Brownian motion and thermophoresis is used. Series solutions for a reduced system of nonlinear ordinary differential equations are obtained by homotopy analysis method (HAM). Comparative study between the HAM solutions and previously published numerical results shows an excellent agreement. Velocity, temperature and mass fraction are displayed for various values of parameters. The local skin friction coefficient, the local Nusselt number and the local Sherwood number are computed. It is observed that the presence of nanoparticles enhances the thermal conductivity of base fluid. It is found that the convective heat transfer coefficient (Nusselt number) is decreased with an increase in concentration of nanoparticles whereas Sherwood number increases when concentration of nanoparticles in the base fluid is increased.

The main objective of this article is to study the effect of 2D coupled mode freeconvection with surface radiation on the fluid flow behavior in an air filled partitionedand shallow cavity subjected to isothermal or insulated boundary conditions. Thedimensionless governing equations under Boussinesq approximation are coupled with aradiative model through the boundaries conditions and solved by the finite volume method.The numerical results are discussed in terms of streamlines, isotherms, convective andradiative Nusselt numbers along the cover plate for various aspect ratios (a, b and c), emissivities andRayleigh number. These results highlighted the condition of the enclosure performance andrevealed among other that isothermal boundaries induce better convective heat exchangecompared to adiabatic cases. Also, it is noticed that varying aspect ratio(a) causesstrong influence on both Nusselt numbers compared to the aspect ratios (b) and (c). The increase of(ϵo) raisesNuconvand decreases Nuradslightly. Whereas, an increase of (ϵC) leads to minorchanges in Nuradwhen (b) or(c) vary,this effect becomes appreciable with increasing (a).

The problem of magnetohydrodyanmic stagnation point flow and heat transfer of second grade fluid past a radially stretching sheet is investigated. The flow problems are examined in the presence of Newtonian heating and Soret and Dufour effects. The relevant mathematical problems are developed through equations of continuity, momentum, energy and concentration. The reduced differential equations are solved for the convergent series solutions. In order to validate the homotopy analysis method (HAM), a comparative study between the present and previous results is made. It is observed that Dufour and Soret effects on temperature and concentration distributions are different. Qualitatively, the influence of Prandtl number on temperature and Schmidt number on concentration is similar. It is further noted that the diffusion of solute in second grade fluid is increasing function of Soret number whereas it decreases when Dufour number increases.