Effects of thermal radiation parameter and magnetic field on the peristaltic motion of Williamson nanofluids in a tapered asymmetric channel

Author(s):  
M. Kothandapani ◽  
J. Prakash
2013 ◽  
Vol 18 (2) ◽  
pp. 599-608
Author(s):  
R. Muthucumaraswamy ◽  
V. Visalakshi

Thermal radiation effects on an unsteady free convective flow of a viscous incompressible flow of a past an exponentially accelerated infinite isothermal vertical plate with uniform mass diffusion in the presence magnetic field are considered. The fluid considered here is a gray, absorbing-emitting radiation but a non-scattering medium. The plate temperature is raised to Tw and the concentration level near the plate is also raised to Cʹw . An exact solution to the dimensionless governing equations is obtained by the Laplace transform method, when the plate is exponentially accelerated with a velocity u= u0 exp(aʹtʹ) in its own plane against gravitational field. The effects of velocity, temperature and concentration fields are studied for different physical parameters such as the magnetic field parameter, thermal radiation parameter, Schmidt number, thermal Grashof number, mass Grashof number and time. It is observed that the velocity increases with decreasing magnetic field parameter or radiation parameter. But the trend is just reversed with respect to a or t .


Author(s):  
Bandaru Mallikarjuna ◽  
Srinivas Jangili ◽  
G. Gopi Krishna ◽  
O. A. Beg ◽  
Ali Kadir

Abstract Electromagnetic high-temperature therapy is popular in medical engineering treatments for various diseases include tissue damage ablation repair, hyperthermia and oncological illness diagnosis. The simulation of transport phenomena in such applications requires multi-physical models featuring magnetohydrodynamics, biorheology, heat transfer and deformable porous media. Motivated by investigating the fluid dynamics and thermodynamic optimization of such processes, in the present article a mathematical model is developed to study the combined influence of thermal buoyancy, magnetic field and thermal radiation on the fluid and heat characteristics in electrically-conducting viscoelastic biofluid flow through a vertical deformable porous medium. Jefferys elastic-viscous model is deployed to simulate non-Newtonian characteristics of the biofluid. It is assumed that heat is generated within the fluid by both viscous and Darcy (porous matrix) dissipations. The boundary value problem is normalized with appropriate transformations. The non-dimensional biofluid velocity, solid displacement and temperature equations with appropriate boundary conditions are solved computationally using a spectral method. Verification of accuracy is conducted via monitoring residuals of the solutions and Validated with shooting technique is included. The effects of Jeffrey viscoelastic parameter, viscous drag parameter, magnetic field parameter, radiation parameter and buoyancy parameter on flow velocity, solid displacement, temperature and entropy generation are depicted graphically and interpreted at length. Increasing magnetic field and drag parameters are found to reduce the field velocity, solid displacement, temperature and entropy production. Higher magnitudes of thermal radiation parameter retard the flow and decrease Nusselt number whereas they elevate solid displacement.


2021 ◽  
Vol 51 (4) ◽  
pp. 229-239
Author(s):  
Sameh E. Ahmed ◽  
R.A Mohamed ◽  
A.M Ali ◽  
A.J Chamkha ◽  
M.S Soliman

This article presents a numerical study for a magnetohydrodynamic flow of a non-Newtonian Casson nanofluid over a stretching sheet embedded in a porous medium under the impacts of non-linear thermal radiation, heat generation/absorption, Joule heating and slips boundary conditions. A two-phase nanofluid model is applied to represent the nanofluid mixture. The porous medium is represented via the Darcy model. A similar solution is obtained for the governing equations and a numerical treatment based on the Runge-Kutta method is conducted to the resulting system of equations.  In this study, the controlling physical parameters are the Casson fluid parameter , the magnetic field , the radiation parameter , the Brownian motion parameter  and the thermophoresis parameter . The obtained results reveal that an increase in the Casson parameter enhances both of the local Nusselt and the Sherwood number while they are reduced as the non-linear radiation parameter increases. In addition, an increase in the magnetic field parameter supports the skin friction coefficient regardless the value of the Casson parameter.


2020 ◽  
Vol 16 ◽  
Author(s):  
M. A. Elogail

Recently, Hasona et al. [1] aimed to investigate the influence of thermal radiation and magnetic field on the peristaltic flow of Carreau nanofluid in a vertical asymmetric channel. The authors have considered the Joule heating, viscous dissipation, chemical reaction, Brownian motion, thermophoresis, Soret, and Dufour effects in their study. Several mistakes and typos were discovered in the study mentioned above, which would affect the obtained results. This report outlines some of these mistakes with suggested corrections to attract the readers' attention through a more in-depth insight into analyzing and exposing these defects.


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