Numerical Solution of Sisko Fluid Over a Stretching Cylinder and Heat Transfer with Variable Thermal Conductivity

2016 ◽  
Vol 32 (5) ◽  
pp. 593-601 ◽  
Author(s):  
M.Y. Malik ◽  
A. Hussain ◽  
T. Salahuddin ◽  
M. Awais ◽  
S. Bilal

AbstractPresent paper addresses the numerical study of Sisko fluid model over stretching cylinder with variable thermal conductivity. The governing equations are simplified by incorporating the boundary layer approximations. After employing suitable similarity transformations partial differential equations are reduced to ordinary differential equations. To obtain numerical solution shooting method in conjunction with Runge-Kutta-Fehlberg method is used. For the analysis of model, variations due to different physical parameters involved in momentum and heat equations are reflected through graphs. Also, the effects of physical parameters on skin-friction coefficient and Nusselt number are represented through graphs as well as tables.

2020 ◽  
Vol 12 (7) ◽  
pp. 168781402093084
Author(s):  
M Ferdows ◽  
Faris Alzahrani ◽  
Shuyu Sun

This article presents a numerical study to investigate boundary-layer heat transfer fluid associated with a moving flat body in cooperation of variable plate and streaming-free velocity along the boundary surface in the laminar flow. The thermal conductivity is supposed to vary linearly with temperature. Similarity transformations are applied to render the governing partial differential equations for mass, momentum and energy into a system of ordinary differential equations to reveal the possible existence of dual solutions. MATLAB package has been used to solve the boundary value problem numerically. We present the effects of various parameters such as velocity ratio, thermal conductivity and variable viscosity on velocity and temperature distribution. The analysis of the results concerning Skin friction and Nusselt number near the wall is also presented. It is focused on the detection and description of the dual solutions. The study reveals that the undertaken problem admits dual solutions in particular range of values of different physical parameters. It can be seen that for the first branch solution, the fluid velocity decreases near the sheet, but it increases far away from the sheet for velocity ratio parameter, whereas the opposite effect is induced for second branch solution. Skin friction coefficient and rate of heat transfer increase due to increase in thermal conductivity parameter.


2017 ◽  
Vol 378 ◽  
pp. 85-101
Author(s):  
Md. Sarwar Alam ◽  
Oluwole Daniel Makinde ◽  
Md. Abdul Hakim Khan

A numerical investigation is performed into the heat transfer and entropy generation of a variable thermal conductivity magnetohydrodynamic flow of Al2O3-water nanofluid in a vertical channel of varying width with right porous wall, which enable the fluid to enter. The effects of the Lorentz force, buoyancy force, viscous dissipation and Joule heating are considered and modeled using the transverse momentum and energy balance equations respectively. The governing nonlinear partial differential equations are transformed into a system of coupled nonlinear ordinary differential equations using appropriate similarity transformations and then solved numerically using power series with Hermite-Padé approximation method. A stability analysis has been performed for the local rate of shear stress and Nusselt number that indicates the existence of dual solution branches. Numerical results are achieved for the fluid velocity, temperature as well as the rate of heat transfer at the wall and the entropy generation of the system. The present results are original and new for the flow and heat transfer past a channel of varying width in a nanofluid which shows that the physical parameters have significant effects on the flow field.


2015 ◽  
Vol 70 (3) ◽  
pp. 163-169 ◽  
Author(s):  
Ahmed M. Megahed

AbstractAn analysis was carried out to describe the problem of flow and heat transfer of Powell–Eyring fluid in boundary layers on an exponentially stretching continuous permeable surface with an exponential temperature distribution in the presence of heat flux and variable thermal conductivity. The governing partial differential equations describing the problem were transformed into a set of coupled non-linear ordinary differential equations and then solved with a numerical technique using appropriate boundary conditions for various physical parameters. The numerical solution for the governing non-linear boundary value problem is based on applying the shooting method over the entire range of physical parameters. The effects of various parameters like the thermal conductivity parameter, suction parameter, dimensionless Powell–Eyring parameters and the Prandtl number on the flow and temperature profiles as well as on the local skin-friction coefficient and the local Nusselt number are presented and discussed. In this work, special attention was given to investigate the effect of the thermal conductivity parameter on the velocity and temperature fields above the sheet in the presence of heat flux. The numerical results were also validated with results from a previously published work on various special cases of the problem, and good agreements were seen.


2019 ◽  
Vol 97 (8) ◽  
pp. 809-815 ◽  
Author(s):  
A. Haider ◽  
T. Salahuddin ◽  
M.Y. Malik

The current investigation is communicated to analyze the characteristics of Darcy–Forchheimer second-grade fluid flow enclosed by a deformable sheet in the existence of both variable thermal conductivity and magnetohydrodynamics. The leading nonlinear energy and momentum partial differential equations are converted into nonlinear ordinary differential equations by utilizing suitable analogous approach. Then the acquired nonlinear problem is numerically calculated by utilizing BVP4C (built in) technique in MATLAB. The influence of certain appropriate physical parameters, namely wall thickness, second-grade fluid, Hartmann number, power index, porosity parameter, inertia coefficient, Prandtl number, and thermal conductivity, on temperature and velocity is studied and deliberated in detail. Numerical calculations of Nusselt number and skin friction for distinct estimations of appearing parameters are analysed through graphs and tables.


Author(s):  
Mazmul Hussain ◽  
Nargis Khan

The variable nature of the thermal conductivity of nanofluid with respect to temperature plays an important role in many engineering and industrial applications including solar collectors and thermoelectricity. Thus, the foremost motivation of this article is to investigate the effects of thermal conductivity and electric conductivity due to variable temperature on the flow of Williamson nanofluid. The flow is considered between two stretchable rotating disks. The mathematical modeling and analysis have been made in the presence of magnetohydrodynamic and thermal radiation. The governing differential equations of the problem are transformed into non-dimensional differential equations by using similarity transformations. The transformed differential equations are thus solved by a finite difference method. The behaviors of velocity, temperature and concentration profiles due to various parameters are discussed. For magnetic parameter, the radial and tangential velocities have showed decreasing behavior, while converse behavior is observed for axial velocity. The temperature profile shows increasing behavior due to an increase in the Weissenberg number, heat generation parameter and Eckert number, while it declines by increasing electric conductivity parameter. The nanoparticle concentration profile declines due to an increase in the Lewis number and Reynolds number.


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