Comment on Steady mixed convection stagnation-point flow of upper convected Maxwell fluids with magnetic field [International Journal of non-linear mechanics, 44(2009):1048-1055]

In this paper, we investigate the effects of second-order slip and magnetic field on the nonlinear mixed convection stagnation-point flow toward a vertical permeable stretching/shrinking sheet in an upper convected Maxwell (UCM) fluid with variable surface temperature. Numerical results are obtained using the bvp4c function from matlab for the reduced skin-friction coefficient, the rate of heat transfer, the velocity, and the temperature profiles. The results indicate that multiple (dual) solutions exist for a buoyancy opposing flow for certain values of the parameter space irrespective to the types of surfaces whether it is stretched or shrinked. It is found that an applied magnetic field compensates the suction velocity for the existence of the dual solutions. Depending on the parametric conditions; elastic parameter, magnetic field parameter, first- and second-order slip parameters significantly controls the flow and heat transfer characteristics. The illustrated streamlines show that for upper branch solutions, the effects of stretching and suction are direct and obvious as the flow near the surface is seen to suck through the permeable sheet and drag away from the origin of the sheet. However, aligned but reverse flow occurs for the case of lower branch solutions when the mixed convection effect is less significant.

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Influence of Non-Linear Thermal Radiation Stagnation Point Flow of Casson Nanofluid Towards a Cylindrical Surface with Non-Uniform Heat Source/Sink and Magnetic Field

Journal of Nanofluids ◽

10.1166/jon.2019.1670 ◽

2019 ◽

Vol 8 (6) ◽

pp. 1201-1212

Author(s):

Dulal Pal ◽

Netai Roy

Keyword(s):

Magnetic Field ◽

Heat Source ◽

Thermal Radiation ◽

Stagnation Point ◽

Cylindrical Surface ◽

Stagnation Point Flow ◽

Casson Nanofluid ◽

Uniform Heat ◽

Non Linear ◽

Source Sink

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MHD mixed convection boundary layer stagnation-point flow on a vertical surface with induced magnetic field

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-11-2016-0436 ◽

2019 ◽

Vol 30 (11) ◽

pp. 4697-4710 ◽

Cited By ~ 2

Author(s):

Fadzilah Md Ali ◽

Kohilavani Naganthran ◽

Roslinda Nazar ◽

Ioan Pop

Keyword(s):

Magnetic Field ◽

Boundary Layer ◽

Stability Analysis ◽

Mixed Convection ◽

Stagnation Point ◽

Stagnation Point Flow ◽

Convection Boundary Layer ◽

Induced Magnetic Field ◽

Content Type ◽

The Stability

Purpose This study aims to perform a stability analysis on a steady magnetohydrodynamic (MHD) mixed convection boundary-layer stagnation-point flow of an incompressible, viscous and electrically conducting fluid over a vertical flat plate. The effect of induced magnetic field is also considered. Design/methodology/approach The governing boundary layer equations are transformed into a system of ordinary differential equations using the similarity transformations. The system is then solved numerically using the “bvp4c” function in MATLAB. Findings Dual solutions are found to exist for a certain range of the buoyancy parameter for both the assisting and opposing flows. The results from the stability analysis showed that the first solution (upper branch) is stable and valid physically, while the second solution (lower branch) is unstable. Practical implications This problem is important in many metallurgical processes, namely, drawing, annealing and tinning of copper wires. The results obtained are very useful for researchers to determine which solution is physically stable, whereby mathematically more than one solution exists for the skin friction coefficient and the heat transfer characteristics. Originality/value The present results of the stability analysis are original and new for the problem of MHD mixed convection stagnation-point flow of viscous conducting fluid over a vertical flat plate, with the effect of induced magnetic field.

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