scholarly journals Entropy analysis and unsteady MHD mixed convection stagnation-point flow of Casson nanofluid around a rotating sphere

2020 ◽  
Vol 59 (3) ◽  
pp. 1693-1703
Author(s):  
A. Mahdy ◽  
Ali J. Chamkha ◽  
Hossam A. Nabwey
2021 ◽  
Vol 409 ◽  
pp. 95-109
Author(s):  
Ephesus Olusoji Fatunmbi ◽  
Samuel Segun Okoya

An analysis of nonlinear mixed convection transport of hydromagnetic Casson nanofluid over a nonlinear stretching sheet near a stagnation point is deliberated in this study. The flow is confined in a porous device in the presence of thermophoresis, Ohmic heating, non-uniform heat source with temperature-dependent thermal conductivity associated with haphazard motion of tiny particles. The transport equations are translated from nonlinear partial differential equations into ordinary ones via similarity transformation technique and subsequently tackled with shooting method coupled with Runge-Kutta Fehlberg algorithm. The significant contributions of the embedded parameters on the dimensionless quantities are graphically depicted and deliberated while the numerical results strongly agree with related published studies in the limiting conditions. It is found that a rise in the magnitude of Casson fluid parameter decelerates the fluid flow while enhancing the viscous drag and thermal profiles. The inclusion of the nonlinear convection term aids fluid flow whereas heat transfer reduces with growth in the thermophoresis and Brownian motion terms.


Author(s):  
R. J. Punith Gowda ◽  
Hogarehally Basavarajappa Mallikarjuna ◽  
B. C. Prasannakumara ◽  
R. Naveen Kumar ◽  
P. T. Manjunatha

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
M. M. Rahman

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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