Flow and heat transfer of a couple-stress fluid sandwiched between viscous fluid layers

2005 ◽  
Vol 83 (7) ◽  
pp. 705-720 ◽  
Author(s):  
J C Umavathi ◽  
A J Chamkha ◽  
M H Manjula ◽  
A Al-Mudhaf

The problem of steady laminar fully developed flow and heat transfer in a horizontal channel consisting of a couple-stress fluid sandwiched between two clear viscous fluids is analyzed analytically. The fluids in all regions are assumed to be incompressible, immiscible, and the transport properties of the fluids in all regions are assumed to be constant. Under these assumptions, the resulting governing equations constitute a set of coupled linear ordinary differential equations that is solved analytically. The closed form solutions obtained for the velocity and temperature fields in the channel are evaluated numerically for various parametric conditions. These results are illustrated graphically to illustrate the effects of the physical parameters governing the flow such as the viscosity ratio, conductivity ratio, couple-stress parameter, Eckert number, and the Prandtl number on the velocity and temperature profiles. In addition, results for the rate of heat transfer are computed for different values of the physical parameters and presented in tabular form. It is found that the effect of the couple stress parameter is to promote the motion of the fluid.PACS Nos.: 44.15.+a

2012 ◽  
Vol 67 (5) ◽  
pp. 217-224 ◽  
Author(s):  
Tasawar Hayat ◽  
Zahid Iqbal ◽  
Muhammad Qasim ◽  
Omar M. Aldossary

This investigation reports the boundary layer flow and heat transfer characteristics in a couple stress fluid flow over a continuos moving surface with a parallel free stream. The effects of heat generation in the presence of convective boundary conditions are also investigated. Series solutions for the velocity and temperature distributions are obtained by the homotopy analysis method (HAM). Convergence of obtained series solutions are analyzed. The results are obtained and discussed through graphs for physical parameters of interest.


2014 ◽  
Vol 18 (suppl.2) ◽  
pp. 475-488 ◽  
Author(s):  
Kalidas Das

Some analyses have been carried out to study the influence of suction/blowing, thermal radiation and temperature dependent fluid properties on the hydro-magnetic incompressible electrically conducting fluid flow and heat transfer over a permeable stretching surface with partial slip boundary conditions. It is assumed that the fluid viscosity and the thermal conductivity vary as an inverse function and linear function of temperature respectively. Using the similarity transformation, the governing system of non-linear partial differential equations are transformed into non-linear ordinary differential equations and are solved numerically using symbolic software MATHEMATICA 7.0. The effects of various physical parameters on the flow and heat transfer characteristics as well as the skin friction coefficient and Nusselt number are illustrated graphically. The physical aspects of the problem are highlighted and discussed.


2018 ◽  
Vol 22 (Suppl. 5) ◽  
pp. 1591-1600 ◽  
Author(s):  
Milos Kocic ◽  
M. Zivojin-Stamenkovic ◽  
Jelena Petrovic ◽  
Milica Nikodijevic

In this paper, flow and heat transfer in a horizontal channel with isothermal walls has been investigated. The upper and lower plate have been kept at the two constant different temperatures, micropolar fluid is electrically conducting, while the channel plates have arbitrary electrical-conductivity. Applied magnetic field is perpendicular to the flow and the full MHD model is investigated. The general equations that describe the discussed problem under the adopted assumptions are reduced to ODE and closed-form solutions are obtained. The profiles of velocity, microrotation, induced magnetic and temperature fields in function of electrical-conductivity and the coupling parameter and the spin-gradient viscosity parameter together with electrical-conductivity, are graphically shown and discussed.


2019 ◽  
Vol 29 (11) ◽  
pp. 4262-4276 ◽  
Author(s):  
C. Jawali Umavathi ◽  
Mikhail Sheremet

Purpose The purpose of this study is a numerical analysis of steady-state heat transfer behavior of couple-stress nanofluid sandwiched between viscous fluids. It should be noted that this research deals with the development of a cooling system for the electronic devices. Design/methodology/approach Stokes model is used to define the couple-stress fluid and the single-phase nanofluid model is used to define the nanofluid transport processes. The fluids in all regions are assumed to be incompressible, immiscible and the transport properties in all the three layers are assumed to be constant. The governing coupled linear ordinary differential equations are made dimensionless by using appropriate fundamental quantities. The exact solutions obtained for the velocity and temperature fields are evaluated numerically for various model parameters. Findings The results are demonstrated using different types of nanoparticles such as copper, silver, silicon oxide (SiO2), titanium oxide (TiO2) and diamond. The investigations are carried out using copper–water nanofluid for different values of couple-stress parameter a with a range of 0 = a = 12, solid volume fraction ϕ with a range of 0.0 ≤ ϕ ≤ 0.05, Eckert number Ec with a range of 0.001 ≤ Ec ≤ 6 and Prandtl number Pr with a range of 0.001 ≤ Pr ≤ 6. It was found that the Nusselt number increases by increasing the couple stress parameter, Eckert number and Prandtl number and it decreases with a growth of the solid volume fraction parameter. It was also observed that using SiO2–water nanofluid, the optimal Nusselt number is obtained. Further, using copper, silver, diamond and TiO2, nanoparticles and water as a base fluid does not show any significant changes in the rate of heat transfer. The couple-stress parameter enhances the velocity and temperature fields whereas the solid volume fraction suppresses the flow field for both Newtonian and couple-stress fluid. Originality/value The originality of this work is to analyze the heat transfer behavior of couple-stress nanofluid sandwiched between viscous fluids. The results would benefit scientists and engineers to become familiar with the analysis of convective heat transfer and flow structures in nanofluids and the way to predict the heat transfer rate in advanced technical systems, in industrial sectors including transportation, power generation, chemical sectors, electronics, etc.


Author(s):  
M. Prasad Siddalinga ◽  
B. S. Shashikala

Nonlinear oberbeck convection of a couple stress fluid in a vertical porous channel in the presence of transverse magnetic field is investigated in this paper. Analytical solution is obtained using the perturbation technique for vanishing values of the buoyancy parameter. Numerical solution of the nonlinear governing equations is obtained using the finite difference technique to validate the results obtained from the analytical solutions. The influence of the physical parameters on the flow, such as couple stress parameter, Hartmann number, temperature parameter, porous parameter and buoyancy parameter are evaluated and presented graphically. A new approach is used to analyse the flow for strong, weak and comparable porosity cases. It is found that increase in porous parameter, couple stress parameter, Hartmann number and temperature parameters decrease the velocity considerably.Kathmandu University Journal of Science, Engineering and Technology Vol. 12, No. I, June, 2016, Page: 49-62


2020 ◽  
Vol 25 (4) ◽  
pp. 148-161
Author(s):  
C.R. Makhalemele ◽  
L. Rundora ◽  
S.O. Adesanya

AbstractIn this paper, the mixed convective flow of an electrically conducting, viscous incompressible couple stress fluid through a vertical channel filled with a saturated porous medium has been investigated. The fluid is assumed to be driven by both buoyancy force and oscillatory pressure gradient parallel to the channel plates. A uniform magnetic field of strength B0 is imposed transverse to the channel boundaries. The temperature of the right channel plate is assumed to vary periodically, and the temperature difference between the plates is high enough to induce radiative heat transfer. Under these assumptions, the equations governing the two-dimensional couple stress fluid flow are formulated and exact solutions of the velocity and the temperature fields are obtained. The effects of radiation, Hall current, porous medium permeability and other various flow parameters on the flow and heat transfer are presented graphically and discussed extensively.


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