The flow of homogeneous fluids through porous media: analogies with other physical problems

This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or “nanofluids,” was measured by over 30 organizations worldwide, using a variety of experimental approaches, including the transient hot wire method, steady-state methods, and optical methods. The nanofluids tested in the exercise were comprised of aqueous and nonaqueous basefluids, metal and metal oxide particles, near-spherical and elongated particles, at low and high particle concentrations. The data analysis reveals that the data from most organizations lie within a relatively narrow band (±10% or less) about the sample average with only few outliers. The thermal conductivity of the nanofluids was found to increase with particle concentration and aspect ratio, as expected from classical theory. There are (small) systematic differences in the absolute values of the nanofluid thermal conductivity among the various experimental approaches; however, such differences tend to disappear when the data are normalized to the measured thermal conductivity of the basefluid. The effective medium theory developed for dispersed particles by Maxwell in 1881 and recently generalized by Nan et al. [J. Appl. Phys. 81, 6692 (1997)], was found to be in good agreement with the experimental data, suggesting that no anomalous enhancement of thermal conductivity was achieved in the nanofluids tested in this exercise.

A Benchmark Study on the Thermal Conductivity of Nanofluids

Impact of Cattaneo–Christov heat flux model in flow of variable thermal conductivity fluid over a variable thicked surface

In this article, the homotopy analysis method is applied to solve nonlinear fractional partial differential equations. On the basis of the homotopy analysis method, a scheme is developed to obtain the approximate solution of the fractional KdV, K(2,2), Burgers, BBM-Burgers, cubic Boussinesq, coupled KdV, and Boussinesq-like B(m,n) equations with initial conditions, which are introduced by replacing some integer-order time derivatives by fractional derivatives. The homotopy analysis method for partial differential equations of integer-order is directly extended to derive explicit and numerical solutions of the fractional partial differential equations. The solutions of the studied models are calculated in the form of convergent series with easily computable components. The results of applying this procedure to the studied cases show the high accuracy and efficiency of the new technique. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2010

Solving nonlinear fractional partial differential equations using the homotopy analysis method

Micropolar nanofluid flow with MHD and viscous dissipation effects towards a stretching sheet with multimedia feature

The peristaltic flow of a magnetohydrodynamic (MHD) Tangent hyperbolic fluid in an inclined asymmetric channel is investigated. The governing equations for the proposed fluid model are derived in Cartesian coordinates system. Simultaneous effects of slip and heat transfer have been taken into account for the present analysis. Regular perturbation method is utilised to get the solutions for stream function, temperature, pressure gradient and heat transfer coefficients. The present solutions are compared with the existing work and comparison is shown through table. The presented graphical results analyse the variations of embedded parameters into the flow system.

Peristaltic flow of a Tangent hyperbolic fluid in an inclined asymmetric channel with slip and heat transfer

Exact analytical solution for flows of an electrically conducting fluid over an infinite oscillatory disk in the presence of a uniform transverse magnetic field is constructed. Both the disk and the fluid are in a state of non-coaxial rotation. Such a flow model has a great significance not only due to its own theoretical interest, but also due to applications to geophysics and engineering. The resulting initial value problem has been solved analytically by applying the Laplace transform technique and the explicit expressions for the velocity for steady and unsteady cases have been established. The analysis of the obtained results shows that the flow field is appreciably influenced by the applied magnetic field, the frequency and rotation parameters.

MHD unsteady flows due to non-coaxial rotations of a disk and a fluid at infinity

The present study examines the comparison of heat transfer properties of magnetohydrodynamic (MHD) rotating traditional nanofluid with that of developing hybrid nanofluid. A new kind of standard fl...

An improvement in heat transfer for rotating flow of hybrid nanofluid: a numerical study

A model for an application to biomedical engineering through nanoparticles

This paper presents a theoretical study for peristaltic flow of a non-Newtonian compressible Maxwell fluid through a tube of small radius. Constitutive equation of upper convected Maxwell model is used for the non-Newtonian rheology. The governing equations are modeled for axisymmetric flow. A regular perturbation method is used for the radial and axial velocity components up to second order in dimensionless amplitude. Exact expressions for the first-order radial and axial velocity components are readily obtained while second-order mean axial velocity component is obtained numerically due to presence of complicated non-homogenous term in the corresponding equation. Based on the mean axial velocity component, the net flow rate is calculated through numerical integration. Effects of various emerging parameters on the net flow rate are discussed through graphical illustrations. It is observed that the net flow rate is positive for larger values of dimensionless relaxation time λ1. This result is contrary to ...

T. Hayat

Papers

Peristaltic flow of a Tangent hyperbolic fluid in an inclined asymmetric channel with slip and heat transfer

MHD unsteady flows due to non-coaxial rotations of a disk and a fluid at infinity

An improvement in heat transfer for rotating flow of hybrid nanofluid: a numerical study

A model for an application to biomedical engineering through nanoparticles

An analysis of peristaltic motion of compressible convected Maxwell fluid