scholarly journals Mixed convection boundary layer flow of a casson fluid near the stagnation point over a permeable surface

2014 ◽  
Vol 10 (1) ◽  
Author(s):  
S. P. M. Isa ◽  
N. M. Arifin ◽  
R. Nazar
Keyword(s):  
Boundary Layer ◽  
Differential Equations ◽  
Mixed Convection ◽  
Stagnation Point ◽  
Boundary Layer Flow ◽  
Velocity Profiles ◽  
Casson Fluid ◽  
Convection Boundary Layer ◽  
Convection Boundary ◽  
Layer Flow

The problem of steady mixed convection boundary layer flow of a Casson fluid near the stagnation-point on a vertical surface when the wall is permeable, where there is suction or injection effect, is considered. The governing partial differential equations are converted into ordinary differential equations by similarity transformation, which is then solved numerically using the shooting method. Results for the skin friction coefficient, local Nusselt number, velocity profiles as well as temperature profiles are presented for different values of the governing parameters. It is found that the imposition of suction is to increase the velocity profiles and to delay the separation of boundary layer, while the injection parameter decreases the velocity profiles.

Mixed Convection Boundary Layer Flow Near the Lower Stagnation Point of a Cylinder Embedded in a Porous Medium Using a Thermal Nonequilibrium Model

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Haliza Rosali ◽  
Anuar Ishak ◽  
Ioan Pop
Keyword(s):  
Boundary Layer ◽  
Porous Medium ◽  
Differential Equations ◽  
Mixed Convection ◽  
Stagnation Point ◽  
Boundary Layer Flow ◽  
Thermal Conductivity Ratio ◽  
Convection Boundary Layer ◽  
Convection Boundary ◽  
Layer Flow

The present paper analyzes the problem of two-dimensional mixed convection boundary layer flow near the lower stagnation point of a cylinder embedded in a porous medium. It is assumed that the Darcy's law holds and that the solid and fluid phases of the medium are not in thermal equilibrium. Using an appropriate similarity transformation, the governing system of partial differential equations are transformed into a system of ordinary differential equations, before being solved numerically by a finite-difference method. We investigate the dependence of the Nusselt number on the solid–fluid parameters, thermal conductivity ratio and the mixed convection parameter. The results indicate that dual solutions exist for buoyancy opposing flow, while for the assisting flow, the solution is unique.

scholarly journals Mixed Convection Boundary Layer Flow over a Stretching Surface Filled with a Maxwell Fluid in Presence of Soret and Dufour Effects

2010 ◽  
Vol 65 (5) ◽  
pp. 401-410 ◽  
Author(s):  
Tasawar Hayat ◽  
Meraj Mustafa ◽  
Said Mesloub
Keyword(s):  
Boundary Layer ◽  
Differential Equations ◽  
Mixed Convection ◽  
Boundary Layer Flow ◽  
Maxwell Fluid ◽  
Convection Boundary Layer ◽  
Porous Space ◽  
Suction Parameter ◽  
Convection Boundary ◽  
Layer Flow

This article looks at the heat and mass transfer characteristics in mixed convection boundary layer flow about a linearly stretching vertical surface. An incompressible Maxwell fluid occupying the porous space takes into account the diffusion-thermo (Dufour) and thermal-diffusion (Soret) effects. The governing partial differential equations are transformed into a set of coupled ordinary differential equations, by invoking similarity transformations. The involved nonlinear differential system is solved analytically using the homotopy analysis method (HAM) to determine the convergent series expressions of velocity, temperature, and concentration. The physical interpretation to these expressions is assigned through graphs and tables for the Nusselt number θ '(0) and the Sherwood number φ '(0). The dependence of suction parameter S, mixed convection parameter λ, Lewis number Le, Prandtl number Pr, Deborah number β , concentration buoyancy parameter N, porosity parameter γ , Dufour number Df, and Soret number Sr is seen on the flow quantities.

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