SLIP EFFECTS IN THE HYDROMAGNETIC FLOW OF A VISCOELASTIC FLUID THROUGH POROUS MEDIUM OVER A POROUS OSCILLATORY STRETCHING SHEET

2017 ◽  
Vol 20 (3) ◽  
pp. 249-262 ◽  
Author(s):  
Nasir Ali ◽  
S. U. Khan ◽  
Muhammad Sajid ◽  
Zaheer Abbas
2015 ◽  
Vol 93 (5) ◽  
pp. 532-541 ◽  
Author(s):  
M. Modather M. Abdou ◽  
E. Roshdy EL-Zahar ◽  
Ali J. Chamkha

An analysis was carried out to study the effect of thermal radiation on magnetohydrodynamic boundary layer flow and heat transfer characteristics of a non-Newtonian viscoelastic fluid near the stagnation point of a vertical stretching sheet in a porous medium with internal heat generation–absorption. The flow is generated because of linear stretching of the sheet and influenced by the uniform magnetic field that is applied horizontally in the flow region. Using a similarity variable, the governing nonlinear partial differential equations have been transformed into a set of coupled nonlinear ordinary differential equations, which are solved numerically using an accurate implicit finite difference scheme. A comparison of the obtained results with previously published numerical results is done and the results are found to be in good agreement. The effects of the viscoelastic fluid parameter, magnetic field parameter, nonuniform heat source–sink, and the thermal radiation parameter on the heat transfer characteristics are presented graphically and discussed. The values of the skin friction coefficient and the local Nusselt number are tabulated for both cases of assisting and opposing flows.


2019 ◽  
Vol 9 (23) ◽  
pp. 5217 ◽  
Author(s):  
Liaqat Ali ◽  
Xiaomin Liu ◽  
Bagh Ali ◽  
Saima Mujeed ◽  
Sohaib Abdal

In this article, we probe the multiple-slip effects on magnetohydrodynamic unsteady Casson nano-fluid flow over a penetrable stretching sheet, sheet entrenched in a porous medium with thermo-diffusion effect, and injection/suction in the presence of heat source. The flow is engendered due to the unsteady time-dependent stretching sheet retained inside the porous medium. The leading non-linear partial differential equations are transmuted in the system of coupled nonlinear ordinary differential equations by using appropriate transformations, then the transformed equations are solved by using the variational finite element method numerically. The velocity, temperature, solutal concentration, and nano-particles concentration, as well as the rate of heat transfer, the skin friction coefficient, and Sherwood number for solutal concentration, are presented for several physical parameters. Next, the effects of these various physical parameters are conferred with graphs and tables. The exact values of flow velocity, skin friction, and Nusselt number are compared with a numerical solution acquired with the finite element method (FEM), and also with numerical results accessible in literature. In the end, we rationalize the convergence of the finite element numerical solution, and the calculations are carried out by reducing the mesh size.


2006 ◽  
Vol 2006 ◽  
pp. 1-14 ◽  
Author(s):  
K. Rajagopal ◽  
P. H. Veena ◽  
V. K. Pravin

The effect of an oscillatory motion of a viscoelastic fluid over an infinite stretching sheet through porous media in the presence of magnetic field with applied suction has been studied. The surface absorbs the fluid in a porous medium in the presence of magnetic field and the velocity oscillates depending on the stretching rate(b). Analytical expressions for the velocity and the coefficient of skin friction have been studied, first by the perturbation method and then by power series method. The effect of viscoelastic parameterk1, porous parameterk2, magnetic parameter Mn, and the vertical distancexin the presence of suction/blowing on the velocity and the flow characteristics are discussed. The velocity of the viscoelastic fluid is found to decrease in the presence of magnetic field and porous media, as compared to the study of viscous fluid. It is also found that the effect of unsteadiness in the wall velocity and skin friction are found to be appreciable in the presence of suction/blowing parameter.


CFD letters ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 52-61
Author(s):  
Haliza Rosali ◽  
Mohd Noor Badlilshah ◽  
Mohamat Aidil Mohamat Johari ◽  
Norfifah Bachok

Boundary layer flow and heat transfer over a stretching sheet in a porous medium has many applications in industrial processes. The effect of porosity plays a significant role in determining the behaviour of the fluid flow. Based on that, we analyzed the unsteady boundary layer stagnation point flow and heat transfer towards a stretching sheet by considering the porosity. The velocity and thermal slip effects are taken into consideration in the present analysis. The governing non-linear partial differential equations were transformed into a system of nonlinear ordinary differential equations using similarity transformation. The resulting ordinary differential equations were solved numerically using the shooting method in Maple software. Numerical results for the dimensionless velocity profile, temperature profile, skin friction coefficients and the local Nusselt number are presented for various parameters. The effect of dimensionless material parameter, thermal slip effect and velocity slip effect on the flow field is also discussed. It is found that the skin friction coefficients decrease whereas the local Nusselt number increases with the increase in permeability parameter.


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