scholarly journals Theoretical study of unsteady oblique stagnation point based Jeffrey nanofluid flow over an oscillatory stretching sheet

2020 ◽  
Vol 12 (11) ◽  
pp. 168781402097188
Author(s):  
Aziz Ullah Awan ◽  
Sana Abid ◽  
Nadeem Abbas

The numerical analysis for two-dimensional oblique stagnation point flow with the magnetohydrodynamic effects of an incompressible unsteady Jeffrey fluid model caused by an oscillatory and stretching sheet has been presented in this article. The Brownian motion and thermophoresis impacts are taken into consideration. The similarity transformation technique is implemented on the governing partial differential equations of the Jeffrey fluid model to obtain a set of nonlinear coupled ordinary differential equations and then these resulting equations are numerically computed with the help of BVP-Maple programming. The variation in the behavior of velocity, temperature, and concentration profile influenced by the governing parameters, has been explicitly explored and displayed through graphs. The numerical results are highlighted in tabular form and through these outcomes, the skin friction coefficient, Nusselt number, and Sherwood number have been investigated. These physical quantities rise for gradually increasing the Hartmann number and ratio of relaxation to retardation time. However, these reduce for gradually growing Jeffrey fluid parameter.

2018 ◽  
Vol 388 ◽  
pp. 420-432
Author(s):  
Vinay Kumar Poorigaly Nanjundaswamy ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Patil Mallikarjun ◽  
Mohaddeseh Mousavi Nezhad ◽  
Giulio Lorenzini

The theoretical study of laminar boundary layer flows of a non-Newtonian fluid past a stretching sheet in an embedded porous medium in the presence of suction/injection is of significant importance in the crystal growing, geothermal, metallurgical, polymer extrusion and several other technological processes. Casson fluid model is one such fluid model used to characterize the behaviour of non-Newtonian fluids. The present article discusses the Casson fluid flow past a permeable stretching sheet in the presence of mass transpiration. The physical problem is modelled into a system of nonlinear partial differential equations which are analytically solved by transforming them into nonlinear ordinary differential equations with constant coefficient by means of similarity transformations. The analysis reveals the effect of Casson parameter on the velocity boundary. In fact, the increasing Casson parameter results in the suppression of velocity boundary. It is found that the skin friction coefficient decreases with the decreasing values of Casson parameter. The effects of Darcy drag force and the mass transpiration are also analyzed by means of various plots.


2012 ◽  
Vol 67 (1-2) ◽  
pp. 70-76 ◽  
Author(s):  
Meraj Mustafa ◽  
Tasawar Hayat ◽  
Pop Ioan ◽  
Awatif Hendi

This article reports the flow of a Casson fluid in the region of stagnation-point towards a stretching sheet. The characteristics of heat transfer with viscous dissipation are also analyzed. The partial differential equations representing the flow and heat transfer of the Casson fluid are reduced to ordinary differential equations through suitable transformations. The flow is therefore governed by the Casson fluid parameter β, the ratio of the free stream velocity to the velocity of the stretching sheet a=c, the Prandtl number Pr, and the Eckert number Ec. The analytic solutions in the whole spatial domain have been computed by the homotopy analysis method (HAM). The dimensionless expressions for the skin friction coefficient and the local Nusselt number have been calculated and discussed.


2015 ◽  
Vol 63 (4) ◽  
pp. 311-317 ◽  
Author(s):  
Tasawar Hayat ◽  
Muhammad Waqas ◽  
Sabir Ali Shehzad ◽  
Ahmed Alsaedi

AbstractThe steady stagnation-point flow of an electrically conducting fluid due to convectively heated stretched disk in the radial direction is considered. Effects of viscous dissipation and Joule heating are present. Mathematical modelling is based upon constitutive relations of Jeffrey fluid. The governing partial differential equations are first transformed into the coupled system of ordinary differential equations and then solved for the convergent series solutions. Numerical values of skin friction coefficient and local Nusselt number are also computed and analysed.


2011 ◽  
Vol 66 (12) ◽  
pp. 705-711 ◽  
Author(s):  
Sin Wei Wong ◽  
Abu Omar Awang ◽  
Anuar Ishak

The steady two-dimensional stagnation-point flow of an incompressible viscous fluid over an exponentially shrinking/stretching sheet is studied. The shrinking/stretching velocity, the free stream velocity, and the surface temperature are assumed to vary in a power-law form with the distance from the stagnation point. The governing partial differential equations are transformed into a system of ordinary differential equations before being solved numerically by a finite difference scheme known as the Keller-box method. The features of the flow and heat transfer characteristics for different values of the governing parameters are analyzed and discussed. It is found that dual solutions exist for the shrinking case, while for the stretching case, the solution is unique.


2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Maria Imtiaz ◽  
Hira Nazar ◽  
Tasawar Hayat ◽  
Ahmed Alsaedi

Abstract The focus of this paper is to study the effects of stagnation point flow and porous medium on ferrofluid flow over a variable thicked sheet. Heat transfer analysis is discussed by including thermal radiation. Suitable transformations are applied to convert partial differential equations to ordinary differential equations. Convergent results for series solutions are calculated. The impact of numerous parameters on velocity and temperature is displayed for series solutions. Graphical behavior for skin friction coefficient and Nusselt number is also analyzed. Numerical values of Nusselt number are tabulated depending upon various parameters


Author(s):  
Muhammad Nazim Tufail ◽  
Musharafa Saleem ◽  
Qasim Ali Chaudhry

The model encountered an unsteady laminar and two-dimensional convective flow of Casson fluid passing through an inclined permeable vertical stretching sheet. The momentum, thermal and concentrated boundary layers (BLs) are used to analyze the unsteady effects of magnetohydrodynamics (MHD) (neglecting induced magnetic field), viscous dissipation, Joule heating and chemical reactions. The governed partial differential equations (PDEs) of the model are reduced to the ordinary differential equations (ODEs). The ξ and χ are selected as the two parameters of the scaling transformations. By using bvp4c with MATLAB, the ODEs are solved numerically and represent their results through the graphs and tables. After the non-dimensionalizing of the equations system, we get the emerging dimensionless parameters. The concentration process was enhanced by the Casson fluid parameter but it reduced the fluid flow and thermal transfer that can be found through the graphical results. The effect of Buoyancy is highlighted as it reduced the velocity profile function, but it is a growing function of the thermal and concentrated profiles. The physical quantities are integrated through the table and graphical analysis. In the center of the wall, the number Shx versus Sc decreases, but at the end it increases.


Author(s):  
T. Hayat ◽  
Z. Iqbal ◽  
M. Mustafa ◽  
A. Alsaedi

Purpose – This investigation has been carried out for thermal-diffusion (Dufour) and diffusion-thermo (Soret) effects on the boundary layer flow of Jeffrey fluid in the region of stagnation-point towards a stretching sheet. Heat transfer occurring during the melting process due to a stretching sheet is considered. The paper aims to discuss these issues. Design/methodology/approach – The authors convert governing partial differential equations into ordinary differential equations by using suitable transformations. Analytic solutions of velocity and temperature are found by using homotopy analysis method (HAM). Further graphs are displayed to study the salient features of embedding parameters. Expressions of skin friction coefficient, local Nusselt number and local Sherwood number have also been derived and examined. Findings – It is found that velocity and the boundary layer thickness are increasing functions of viscoelastic parameter (Deborah number). An increase in the melting process enhances the fluid velocity. An opposite effect of melting heat process is noticed on velocity and skin friction. Practical implications – The boundary layer flow in non-Newtonian fluids is very important in many applications including polymer and food processing, transpiration cooling, drag reduction, thermal oil recovery and ice and magma flows. Further, the thermal diffusion effect is employed for isotope separation and in mixtures between gases with very light and medium molecular weight. Originality/value – Very scarce literature is available on thermal-diffusion (Dufour) and diffusion-thermo (Soret) effects on the boundary layer flow of Jeffrey fluid in the region of stagnation-point towards a stretching sheet with melting heat transfer. Series solution is developed using HAM. Further, the authors compare the present results with the existing in literature and found excellent agreement.


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.


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