Temperature Dependent Suction/Injection and Variable Properties on Non-Newtonian Casson Mixed Convective MHD Laminar Fluid Flow with Viscous Dissipation and Thermal Radiation

Purpose The main purpose of this numerical work is to study free convection of Casson fluid in a square differentially heated cavity taking into account the effects of thermal radiation and viscous dissipation. Design/methodology/approach The cavity is heated from the left vertical wall and cooled from the right vertical wall while horizontal walls are insulated. The governing partial differential equations invoking Rosseland approximation for thermal radiation with corresponding boundary conditions have been solved by finite difference method of the second-order accuracy using dimensionless variables stream function, vorticity and temperature. The governing parameters are Rayleigh number (Ra = 105), Prandtl number (Pr = 0.1, 0.7, 7.0), Casson parameter (γ = 0.1-5.0), radiation parameter (Rd = 0-10), Eckert number (Ec = 0-1.0). Findings It is found that an increase in Casson parameter leads to the heat transfer enhancement and fluid flow intensification. While a growth of Eckert number illustrates the heat transfer suppression. Originality/value The originality of this work is to analyze for the first-time natural convective fluid flow and heat transfer of a Casson fluid within a differentially heated square cavity under the effects of thermal radiation and viscous dissipation. The results would benefit scientists and engineers to become familiar with the flow behavior of such non-Newtonian fluids, and the way to predict the properties of this flow for possibility of using this specific fluid in various engineering and industrial processes, such as chyme movement in intestine, blood flows, lubrication processes with grease and heavy oils, glass blowing, electronic chips, food stuff, slurries, etc.

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Numerical study on combined thermal radiation and magnetic field effects on entropy generation in unsteady fluid flow past an inclined cylinder

Journal of Computational Design and Engineering ◽

10.1093/jcde/qwaa068 ◽

2020 ◽

Author(s):

Zachariah Mbugua Mburu ◽

Sabyasachi Mondal ◽

Precious Sibanda

Keyword(s):

Magnetic Field ◽

Fluid Flow ◽

Thermal Radiation ◽

Viscous Dissipation ◽

Chemical Reaction ◽

Entropy Generation ◽

Magnetic Field Effects ◽

Slip Conditions ◽

Field Effects ◽

Flow Past

Abstract This study reports on combined thermal radiation, chemical reaction, and magnetic field effects on entropy generation in an unsteady nanofluid flow past an inclined cylinder using the Buongiorno model. We consider the impact of viscous dissipation, velocity slip conditions, thermal slip conditions, and the Brownian motion. The transport equations governing the flow are solved using an overlapping grid spectral collocation method. The results indicate that entropy generation is suppressed significantly by thermal radiation and chemical reaction parameters but enhanced with the magnetic field, viscous dissipation, the Brinkman number, and the Reynolds number. Also, fluid flow variables are affected by the thermophoresis parameter, the angle of cylinder inclination, and the Richardson number. We present the findings of the skin friction coefficient, the Nusselt number, and the Sherwood number. The model is applicable in fields such as the petroleum industry, building industries, and medicine.

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