scholarly journals Three-dimensional boundary layer flow of nanofluids due to an unsteady stretching surface

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
A. Mahdy

A numerical solution has been obtained for the unsteady three-dimensional stretching flow and heat transfer due to uncertainties of thermal conductivity and dynamic viscosity of nanofluids. The term of nanofluid refers to a solid–liquid mixture with a continuous phase which is a nanometer sized nanoparticle dispersed in conventional base fluids. The unsteadiness in the flow and temperature fields is caused by the time-dependent of the stretching velocity and the surface temperature.  Different water-based nanofluids containing Cu, Ag, and TiO2 are taken into consideration. The governing partial differential equations with the auxiliary conditions are converted to ordinary differential equations with the appropriate corresponding conditions via scaling transformations. Comparison with known results for steady state flow is presented and it found to be in excellent agreement.

2008 ◽  
Vol 86 (6) ◽  
pp. 853-855 ◽  
Author(s):  
A Ishak ◽  
R Nazar ◽  
I Pop

The unsteady laminar boundary-layer flow over a continuously stretching surface in a viscous and incompressible quiescent fluid is studied. The unsteadiness in the flow and temperature fields is caused by the time dependence of the stretching velocity and the surface heat flux. The nonlinear partial differential equations of continuity, momentum, and energy, with three independent variables, are reduced to nonlinear ordinary differential equations, before they are solved numerically by the Keller-box method. Comparison with available data from the open literature as well as the exact solution for the steady-state case of the present problem is made, and found to be in good agreement. Effects of the unsteadiness parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined.PACS No.: 47.15.Cb


2016 ◽  
Vol 12 (7) ◽  
pp. 6412-6421
Author(s):  
Ajala O.A ◽  
Aseelebe L. O ◽  
Ogunwobi Z. O

A steady two dimensional boundary layer flow and heat transfer with variable viscosity electrically conducting fluid at T in the presence of magnetic fields and thermal radiation was considered. The governing equations which are partial differential equations were transformed into ordinary differential equations using similarity variables, and the resulting coupled ordinary differential equations were solved using collocation method in MAPLE 18. The velocity and temperature profiles were studied graphically for different physical parameters. The effects of the parameters on velocity and temperature profile were showed.


2019 ◽  
Vol 33 (26) ◽  
pp. 1950307 ◽  
Author(s):  
Sumit Gupta ◽  
Devendra Kumar ◽  
Jagdev Singh

This work examines the magnetohydrodynamic (MHD) three-dimensional (3D) flow comprising Cu and Al2O3 water-based nanofluids. The effects of heat and mass transfer with the effects of nanoparticles are carried out in the existence of thermal radiation and convective heat and mass transfer boundary conditions. By applying the proper similarity transformations the partial differential equations describing velocity, temperature and nanoparticle volume fraction (NVF) are transformed to a system of nonlinear ordinary differential equations (NODE). An optimal homotopy analysis technique is applied to evaluate the analytical solutions. The influences of pertinent parameters on the velocity, temperature and NVF are displayed in graphical and tabular forms. Calculations of Nusselt number, skin friction coefficients and the local Sherwood number are evaluated via tables. An excellent comparison has also been made with the previously-published literature.


2017 ◽  
Vol 377 ◽  
pp. 155-165 ◽  
Author(s):  
Paras Ram ◽  
Vimal Kumar Joshi ◽  
Oluwole Daniel Makinde

This article presents a numerical investigation on the convective heat transfer behaviour of time-dependent three-dimensional boundary layer flow of nano-suspension over a radially stretchable surface. The modeled set of governing nonlinear coupled ODEs is solved using the finite difference scheme followed by the shooting technique. For understanding the effects of various physical parameters such as geothermal viscosity, stretching parameter and viscous dissipation on the flow and temperature fields, magnetite-hydrocarbon nanofluid 90G is taken. The heat transfer rate and skin frictions due to the above physical parameters are also computed. The derived results show that among these parameters, Eckert number has a dominating role in the heat transfer. After a critical value of the Eckert number, the rotating surface is no longer getting cooled, rather, it takes up heat despite the fact that the surface temperature is more than the ambient temperature.


2012 ◽  
Vol 134 (4) ◽  
Author(s):  
T. Hayat ◽  
M. Awais ◽  
S. Obaidat

This paper discusses the mixed convection three-dimensional boundary layer flow of upper-convected Maxwell fluid over a stretching surface. Magnetohydrodynamic (MHD) combined with Soret and Dufour effects are also taken into account. The governing problems are first modeled and then solved by a homotopy analysis method (HAM). The variations of several parameters of interest on the velocity, concentration, and temperature fields are analyzed by the presentation of graphs. Several known results have been pointed out as the particular cases of the present analysis.


2013 ◽  
Vol 29 (3) ◽  
pp. 559-568 ◽  
Author(s):  
G. C. Shit ◽  
R. Haldar ◽  
A. Sinha

AbstractA non-linear analysis has been made to study the unsteady hydromagnetic boundary layer flow and heat transfer of a micropolar fluid over a stretching sheet embedded in a porous medium. The effects of thermal radiation in the boundary layer flow over a stretching sheet have also been investigated. The system of governing partial differential equations in the boundary layer have reduced to a system of non-linear ordinary differential equations using a suitable similarity transformation. The resulting non-linear coupled ordinary differential equations are solved numerically by using an implicit finite difference scheme. The numerical results concern with the axial velocity, micro-rotation component and temperature profiles as well as local skin-friction coefficient and the rate of heat transfer at the sheet. The study reveals that the unsteady parameter S has an increasing effect on the flow and heat transfer characteristics.


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