Influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel

The influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel is investigated.The DarcyBrinkman model is used to characterize the fluid flow dynamics in porous materials.The analytical solutions are obtained for the unidirectional and completely developed flow.Based on a normal mode analysis,the generalized eigenvalue problem under a perturbed state is solved.The eigenvalue problem is then solved by the spectral method.Finally,the critical Rayleigh number with the corresponding wavenumber is evaluated at the assigned values of the other flow-governing parameters.The results show that increasing the Darcy number,the Lewis number,the Dufour parameter,or the Soret parameter increases the stability of the system,whereas increasing the inclination angle of the channel destabilizes the flow.Besides,the flow is the most unstable when the channel is vertically oriented.

Natural convection flow of a couple stress fluid between two vertical parallel plates with Hall and ion-slip effects

The Hall and ion-slip effects on fully developed electrically conducting couple stress fluid flow between vertical parallel plates in the presence of a temperature dependent heat source are investigated. The governing non-linear partial differential equations are transformed into a system of ordinary differential equations using similarity transformations. The resulting equations are then solved using the homotopy analysis method （HAM）. The effects of the magnetic parameter, Hall parameter, ion-slip parameter and couple stress fluid parameter on velocity and temperature are discussed and shown graphically

Steady rotation of a composite sphere in a concentric spherical cavity

The problem of steady rotation of a composite sphere located at the centre of a spherical container has been investigated. A composite particle referred to in this paper is a spherical solid core covered with a permeable spherical shell. The Brinkman＇s model for the flow inside the compos- ite sphere and the Stokes equation for the flow in the spheri- cal container were used to study the motion. The torque ex- perienced by the porous spherical particle in the presence of cavity is obtained. The wall correction factor is calculated. In the limiting cases, the analytical solution describing the torque for a porous sphere and for a solid sphere in an un- bounded medium are obtained from the present analysis.

Couple stress nanofluid flow through a bifurcated artery—Application of catheterization process

In this article,we are exploring the hemodynamics of nanofluid,flowing through a bifurcated artery with atherosclerosis in the presence of a catheter.For treating obstruction in the artery,one can use the catheter whose outer surface is carrying the drug coated with nano-particles.The resultant solvent is considered as blood nano-fluid.Blood being a complex fluid,is modeled by couple stress fluid.In the presence of nano-particles,the temperature and the concentration distribution are understood in a bifurcated stenotic artery.The concluded mathematical model is governed by coupled non-linear equations,and are solved by using the homotopy perturbation method.Consequently,we have explored is the effects of fluid and the embedded geometric parameters on the hemodynamics characteristics.It is also realized that high wall shear stress exists for couple stress nano-fluid when compared to Newtonian nano-fluid.which is computed at a location corresponding to maximum constriction(z=12.5)of the artery.

Effect of thermal radiation on mixed convection of a nanofluid from an inclined wavy surface embedded in a non-Darcy porous medium with wall heat flux

This article focuses on the effect of radiation on mixed convection in a nanofluid along an inclined wavy surface embedded in a non-Darcy porous medium.A coordinate transformation is employed to transform the complex wavy surface to a smooth surface.The governing equations are transformed into a set of partial differential equations using the nonsimilarity transformation and then a local similarity and non-similarity method is applied to obtain coupled ordinary differential equations.These resulting equations are linearized using the successive linearization method and then solved by the Chebyshev spectral method.The effects of radiation,non-Darcy parameter,Brownian motion parameter,thermophoresis parameter,the amplitude of the wavy surface,angle of inclination of the wavy surface on the non-dimensional heat and nanoparticle mass transfer rates are studied and presented graphically.

Mixed Convection Heat and Mass Transfer in a Micropolar Fluid with Soret and Dufour Effects

A mathematical model for the steady,mixed convection heat and mass transfer along a semi-infinite vertical plate embedded in a micropolar fluid in the presence of Soret and Dufour effects is presented.The non-linear governing equations and their associated boundary conditions are initially cast into dimensionless forms using local similarity transformations.The resulting system of equations is then solved numerically using the Keller-box method.The numerical results are compared and found to be in good agreement with previously published results as special cases of the present investigation.The non-dimensional velocity,microrotation,temperature and concentration profiles are displayed graphically for different values of coupling number,Soret and Dufour numbers.In addition,the skin-friction coefficient,the Nusselt number and Sherwood number are shown in a tabular form.