scholarly journals Skin Friction and Heat Transfer in Combined Convection from a Sphere to a Non-Newtonian Fluid

2017 ◽  
Vol 65 (1) ◽  
pp. 21-25
Author(s):  
Nepal C Roy ◽  
Amir Husen

Steady-state laminar combined convection flow of an electrically conducting, non-Newtonian fluid past a sphere is studied numerically. The effects of the power-law index, the mixed convection parameter, the magnetic field parameter and the heat generation or absorption parameter on the skin friction and the heat transfer are illustrated. The skin friction for dilatant fluids is smaller than that for pseudoplastics. Near the stagnation point, the Nusselt number reduces rapidly for pseudoplastics and reaches sharply a maximum value for dilatant fluids. Both the skin friction and the Nusselt number decrease owing to an increase of the magnetic field parameter. Moreover the heat generation produces higher skin friction and lower Nusselt number. Dhaka Univ. J. Sci. 65(1): 21-25, 2017 (January)

2020 ◽  
Vol 12 (5) ◽  
pp. 657-661
Author(s):  
Zohreh Aliannejadi

In many cases such as production of metal sheets, the behavior of fluid flow and heat transfer in the neighborhood of a hot plate is very important. The CFD simulation of fluid flow is a widespread study that reveals detail information about the fluid flow in the calculated domain. In this study, the flow and heat transfer of a specific fluid in the above area of a stretching plate is examined analytically to find the variation of skin friction and Nusselt number. For this purpose, the similarity transformations can be employed to achieve the ordinary differential equations from the governing partial differential equations. The optimal homotopy asymptotic method (OHAM) is used to solve the ordinary differential equations which is applicable in solving of nonlinear equations. The effects of magnetic field on the analytical results from solving the equations are evaluated in detail. It is found that the thickness of the flow boundary layer decreases and the thickness of the thermal boundary layer increases by increasing in the magnetic field. Moreover, the Nusselt number is lower and skin friction is higher for the higher values of the magnetic field.


Inventions ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 7
Author(s):  
Muhammad Saleem Iqbal ◽  
Abuzar Ghaffari ◽  
Arshad Riaz ◽  
Irfan Mustafa ◽  
Muhammad Raza

The current article incorporates the numerical investigation of heat exchange rate and skin friction carried out through nanofluid saturated with thermally balanced porous medium over a rough horizontal surface that follows the sinusoidal waves. The effects of the external magnetic field are discussed by managing the magnetic field strength applied normally to the flow pattern. The occurring partial differential governing equations are grasped through a strong numerical scheme of the Keller box method (KBM) against the various parameters. The findings are elaborated through tables and diagrams of velocity, temperature, skin friction, Nusselt number, streamlines, and heat lines. The percentage increase in Nusselt number and coefficient of skin friction over the flat and wavy surface is calculated which leads to the conclusion that the copper (Cu) nanoparticles are better selected as compared to the silver (Ag) for heat transfer enhancement. It is also evident from sketches that the current analysis can be used to enhance the surface drag force by means of nanoparticles. It is a matter of interest that the magnetic field can be used to manage the heat transfer rate in such a complicated surface flow. The current readings have been found accurate and valid when compared with the existing literature.


Author(s):  
S Shuchi ◽  
K Sakatani ◽  
H Yamaguchi

An investigation was conducted for heat transfer characteristics of binary magnetic fluid flow in a partly heated circular pipe experimentally. The boiling heat transfer characteristics on the effects of the relative position of the magnetic field to the heated region were particularly considered in the present study. From the experimental verification, the Nusselt number, representing boiling heat transfer characteristics, was obtained for various flow and magnetic conditions which were represented by the non-dimensional parameters of the Reynolds number and the magnetic pressure number. Additionally, the rate of change of the Nusselt number found by applying the magnetic field was also estimated and the optimal position of the field to the partly heated region was discussed. The results indicated that the effect of the magnetic field to the heat transfer rate from the heated wall was mainly subjected to the effect of the vortices induced in the magnetic field region and the possibility of controlling the heat transfer rate by applying an outer magnetic field to utilize the effect.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Zulqurnain Sabir ◽  
Rizwan Akhtar ◽  
Zhu Zhiyu ◽  
Muhammad Umar ◽  
Ali Imran ◽  
...  

In this study, an attempt is made to explore the two-phase Casson nanofluid passing through a stretching sheet along a permeable surface with the effects of chemical reactions and gyrotactic microorganisms. By utilizing the strength of similarity transforms the governing PDEs are transformed into set of ODEs. The resulting equations are handled by using a proficient numerical scheme known as the shooting technique. Authenticity of numerical outcomes is established by comparing the achieved results with the MATLAB built-in solver bvp4c. The numerical outcomes for the reduced Nusselt number and Sherwood number are exhibited in the tabular form, while the variations of some crucial physical parameters on the velocity, temperature, and concentration profiles are demonstrated graphically. It is observed that Local Nusselt number rises with the enhancement in the magnetic field parameter, the porous media parameter, and the chemical reactions, while magnetic field parameter along with porous media parameter retards the velocity profile.


1989 ◽  
Vol 67 (10) ◽  
pp. 971-973
Author(s):  
K. D. Krori ◽  
J. C. Sarmah

In this paper, we present a study of the stable polar trajectories ([Formula: see text] = constant plane) of neutral test particles around a Schwarzschild black hole embedded in a magnetic field. We also show how the nature of these trajectories changes with the variation in the angular momentum of the test particle and the magnetic field parameter.


Author(s):  
Wekesa Waswa Simon ◽  
Winifred Nduku Mutuku

Heat transfer fluids play a vital role in many engineering and industrial sectors such as power generation, chemical production, air-conditioning, transportation and microelectronics. Aim: To numerically investigate the effect of double stratification on magneto-hydrodynamic boundary layer flow and heat transfer of an Eyring-Powell fluid. Study Design: Eyring-Powell fluid is one of the non-Newtonian fluid that possess different characteristics thus different mathematical models have been formulated to describe such fluids by appropriate substitution into Navier-Stoke’s equations. The challenging complexity and the nature of the resultant equations are of great interest hence attract many investigations. Place and Duration of Study: Department of Mathematics and Actuarial Science, Kenyatta University, Nairobi, Kenya between December 2019 and October 2020. Methodology: The resultant nonlinear equations are transformed to linear differential equations by introducing appropriate similarity transformations. The resulting equations are solved numerically by simulating the predictor-corrector (P-C) method in matlab ode113. The results are graphically depicted and analysed to illustrate the effects of magnetic field, thermophoresis, thermal stratification, solutal stratification, material fluid parameters and Grashoff number on the fluid velocity, temperature, concentration, local Sherwood number and local Nusselt number. Results: The results show that increasing the magnetic field strength, thermophoresis, thermal stratification and solutal stratification lead to a decrease in the fluid velocity, temperature, Sherwood number, Nusselt number and skin friction while an increase in the magnetic field strength, thermal stratification, solutal stratification, and thermophoresis increases the fluid concentration. Conclusion: The parameters in this study can be varied to enhance heat ejection of Eyring-Powell fluid and applied in industries as a coolant or heat transfer fluid.


2013 ◽  
Vol 18 (1) ◽  
pp. 259-267 ◽  
Author(s):  
R. Muthucumaraswamy ◽  
V. Valliammal

An exact solution of an unsteady flow past an exponentially accelerated infinite isothermal vertical plate with uniform mass diffusion in the presence of a transverse magnetic field has been studied. The plate temperature is raised to Tw and the species concentration level near the plate is also made to rise Cʹw . The dimensionless governing equations are solved using the Laplace-transform technique. The velocity, temperature and concentration profiles are studied for different physical parameters such as the magnetic field parameter, chemical reaction parameter, thermal Grashof number, mass Grashof number, Schmidt number, time and a. It is observed that the velocity decreases with increasing the magnetic field parameter.


2003 ◽  
Vol 81 (5) ◽  
pp. 789-795 ◽  
Author(s):  
H A Attia

In this paper, the unsteady flow of a dusty viscous incompressible electrically conducting non-Newtonian power-law fluid through a circular pipe is investigated. A constant pressure gradient in the axial direction and a uniform magnetic field directed perpendicular to the flow direction are applied. The particle phase is assumed to behave as a viscous fluid. A numerical solution is obtained for the governing nonlinear momentum equations using finite differences. The effects of the magnetic-field parameter Ha, the non-Newtonian fluid characteristics (the flow index n), and the particle-phase viscosity β on the transient behavior of the velocity, volumetric flow rates, and skin friction coefficients of both fluid and particle phases are studied. It is found that all the flow parameters for both phases decrease as the magnetic field increases or the flow index decreases. On the other hand, increasing the particle-phase viscosity increases the skin friction of the particle phase, but decreases the other flow parameters. PACS No.: 47.50.+d


2000 ◽  
Vol 78 (9) ◽  
pp. 875-882 ◽  
Author(s):  
H A Attia

The steady laminar flow of an incompressible viscous electrically conducting non-Newtonian fluid of second grade impinging normal to a plane wall with heat transfer is investigated. An externally applied uniform magnetic field is applied normal to the wall, which is maintained at a constant temperature. A numerical solution for the governing momentum and energy equations is obtained. The effect of the characteristics of the non-Newtonian fluid and the magnetic field on both the flow and heat transfer is outlined. PACS Nos.: 47.50 and 47.15


2013 ◽  
Vol 18 (4) ◽  
pp. 1087-1097
Author(s):  
R. Muthucumaraswamy ◽  
N. Dhanasekar ◽  
G. Easwara Prasad

Abstract An exact analysis of rotation effects on an unsteady flow of an incompressible and electrically conducting fluid past a uniformly accelerated infinite isothermal vertical plate, under the action of a transversely applied magnetic field is presented. The plate temperature is raised linearly with time and the concentration level near the plate is also raised to C’w. The dimensionless governing equations are solved using the Laplace-transform technique. The velocity profiles, temperature and concentration are studied for different physical parameters such as the magnetic field parameter, chemical reaction parameter, thermal Grashof number, mass Grashof number, Schmidt number, Prandtl number and time. It is observed that the velocity increases with increasing values of the thermal Grashof number or mass Grashof number. It is also observed that the velocity increases with decreasing values of the magnetic field parameter or rotation parameter Ω.


Sign in / Sign up

Export Citation Format

Share Document