scholarly journals Micromagnetorotation of MHD Micropolar Flows

Symmetry ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 148 ◽  
Author(s):  
Kyriaki-Evangelia Aslani ◽  
Lefteris Benos ◽  
Efstratios Tzirtzilakis ◽  
Ioannis E. Sarris
Keyword(s):  
Magnetic Field ◽  
Skin Friction ◽  
Magnetic Energy ◽  
Skin Friction Coefficient ◽  
Channel Height ◽  
Future Design ◽  
Crucial Effect ◽  
Mixed Pattern ◽  
Electric Effect ◽  
Micropolar Flows

The studies dealing with micropolar magnetohydrodynamic (MHD) flows usually ignore the micromagnetorotation (MMR) effect, by assuming that magnetization and magnetic field vectors are parallel. The main objective of the present investigation is to measure the effect of MMR and the possible differences encountered by ignoring it. The MHD planar Couette micropolar flow is solved analytically considering and by ignoring the MMR effect. Subsequently, the influence of MMR on the velocity and microrotation fields as well as skin friction coefficient, is evaluated for various micropolar size and electric effect parameters and Hartmann numbers. It is concluded that depending on the parameters’ combination, as MMR varies, the fluid flow may accelerate, decelerate, or even excite a mixed pattern along the channel height. Thus, the MMR term is a side mechanism, other than the Lorentz force, that transfers or dissipates magnetic energy in the flow direct through microrotation. Acceleration or deceleration of the velocity from 4% to even up to 45% and almost 15% deviation of the skin friction were measured when MMR was considered. The crucial effect of the micromagnetorotation term, which is usually ignored, should be considered for the future design of industrial and bioengineering applications.

Boundary layer flow near stagnation-points on a vertical surface with slip in the presence of transverse magnetic field

2014 ◽  
Vol 24 (3) ◽  
pp. 643-653 ◽  
Author(s):  
Ibrahim Yakubu Seini ◽  
Daniel Oluwole Makinde
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Boundary Layer ◽  
Friction Coefficient ◽  
Skin Friction ◽  
Stagnation Point ◽  
Vertical Surface ◽  
Skin Friction Coefficient ◽  
Content Type ◽  
Layer Flow

Purpose – The purpose of this paper is to investigate the MHD boundary layer flow of viscous, incompressible and electrically conducting fluid near a stagnation-point on a vertical surface with slip. Design/methodology/approach – In the study, the temperature of the surface and the velocity of the external flow are assumed to vary linearly with the distance from the stagnation-point. The governing differential equations are transformed into systems of ordinary differential equations and solved numerically by a shooting method. Findings – The effects of various parameters on the heat transfer characteristics are discussed. Graphical results are presented for the velocity and temperature profiles whilst the skin-friction coefficient and the rate of heat transfers near the surface are presented. It is observed that the presence of the magnetic field increases the skin-friction coefficient and the rate of heat transfer near the surface towards the stagnation-point. Originality/value – The presence of magnetic field increases the skin-friction coefficient and the rate of heat transfer near the surface towards the stagnation-point.

On Two-Dimensional Laminar Hydromagnetic Fluid-Particle Flow Over a Surface in the Presence of a Gravity Field

2000 ◽  
Vol 123 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Ali J. Chamkha
Keyword(s):  
Magnetic Field ◽  
Friction Coefficient ◽  
Skin Friction ◽  
Analytical Solutions ◽  
Fluid Phase ◽  
Skin Friction Coefficient ◽  
Two Dimensional ◽  
Particle Phase ◽  
Phase Stresses ◽  
The Magnetic Field

A continuum two-phase fluid-particle model accounting for particle-phase stresses and a body force due to the presence of a magnetic field is developed and applied to the problem of two-dimensional laminar hydromagnetic flow of a particulate suspension over a horizontal surface in the presence of a gravity field. Analytical solutions for the velocity distributions and the skin-friction coefficients of both phases are reported. Two cases of wall hydrodynamic (velocity) conditions corresponding to stationary and oscillatory velocity distributions are considered. Numerical evaluations of the analytical solutions are performed and the results are reported graphically to elucidate special features of the solutions. The effects of the particle-phase stresses and the magnetic field are illustrated through representative results for the horizontal velocity profiles, fluid-phase displacement thickness, and the complete skin-friction coefficient for various combinations of the physical parameters. It is found that the presence of the magnetic field increases the fluid-phase skin-friction coefficient for various particulate volume fraction levels while the presence of the particle-phase viscous stresses reduces it for various particle-to-fluid density ratios.

scholarly journals A numerical approach for two-dimensional Sutterby fluid flow bounded at a stagnation point with an inclined magnetic field and thermal radiation impacts

2020 ◽  
pp. 186-186 ◽  
Author(s):  
Zulqurnain Sabir ◽  
Ali Imran ◽  
Muhammad Umar ◽  
Muhammad Zeb ◽  
Muhammad Shoaib ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Nusselt Number ◽  
Thermal Radiation ◽  
Skin Friction ◽  
Velocity Ratio ◽  
Skin Friction Coefficient ◽  
Deborah Number ◽  
Inclined Magnetic Field ◽  
Runge Kutta Method ◽  
Power Law Index

The present study investigates the impacts of thermal radiation and inclined magnetic field on the Sutterby fluid by capitalizing Cattaneo-Christov heat flux system. The suitable transformations from partial differential equations (PDEs) into ordinary differential equations (ODEs) are achieved by capitalizing the strength of similarity conversion system. Well known numerical shooting technique is used along with integrated strength Runge Kutta method of fourth order. The proposed results are compared with Lobatto 111A method which strengthen the convergence and accuracy of present fluidic system. The skin friction coefficients and Nusselt number are numerically exhibited in tabular form, while the parameter of interests in terms of velocity ratio parameter, power law index, the thermal radiation parameter, Prandtl number, Deborah number, magnetic parameter. Here in this contemporary investigation, the phenomenon of thermal radiation on an inclined magnetic field using Sutterby capitalizing Cattaneo-Christov heat flux model has been discussed. The resulting complex nonlinear ODEs are tackled numerically by utilizing a famous shooting technique with the integrated strength of the Runge-Kutta method of fourth order. The obtained numerical results are compared with the MATLbuilt-in solver bvp4c. The numerical values of the skin friction coefficient and reduced Nusselt number are narrated in tabular form, while some proficient parameters like velocity ratio parameter, power-law index, Deborah number, magnetic parameter, inclined magnetic angle, the thermal radiation parameter, Reynolds number and Prandtl number on the velocity and temperature profiles have been discussed numerically as well as graphically. Outcomes of the proposed research show that by increasing the inclined angle, enhancement is seen in the skin-friction coefficient and reduces the Nusselt number. Moreover, by increasing the Reynolds number, the temperature profile declines initially and then moves upward in the channel. The stability and convergence of the proposed methodolgy in validated through residual errors based different tolerances.

Numerical solution of MHD Sisko fluid over a stretching cylinder and heat transfer analysis

2016 ◽  
Vol 26 (6) ◽  
pp. 1787-1801 ◽  
Author(s):  
M.Y. Malik ◽  
Arif Hussain ◽  
T. Salahuddin ◽  
M. Awais
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Nusselt Number ◽  
Differential Equations ◽  
Skin Friction ◽  
Skin Friction Coefficient ◽  
Stretching Cylinder ◽  
Sisko Fluid ◽  
Content Type ◽  
Curvature Parameter

Purpose – The purpose of this paper is to examine the Sisko fluid model over a stretching cylinder with heat transfer and magnetohydrodynamics. Design/methodology/approach – The boundary layer approach is employed to simplify the governing equations. Suitable similarity transformations are used to transform the governing partial differential equations into ordinary differential equations. In order to solve this system of ordinary differential equations numerically, shooting method in conjunction with Runge-Kutta-Fehlberg method is used. Findings – The effects of physical parameters involved in velocity and temperature profiles are shown through graphs. It is observed that Sisko fluid parameter and curvature parameter enhances fluid velocity while motion of fluid is retarded by increasing magnetic field strength. Additionally temperature of fluid raise with curvature parameter while it fall down for larger values of Prandtl number. Skin friction coefficient and Nusselt number are computed and presented in graphs and tables for further analysis. It can be seen that curvature parameter increases both skin friction and Nusselt number while magnetic field and Prandtl number decayed skin friction and Nusselt number, respectively. Also Sisko parameter enlarges skin friction coefficient. The accuracy of solution is verified by comparing it with existing literature. Originality/value – The computed results are interested for industrial and engineering processes, especially in cooling of nuclear reactors.

scholarly journals Aligned Magnetic Field and Radiation Effects on Biomagnetic Fluid over an Unsteady Stretching Sheet with Various Slip Conditions

AppliedMath ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 37-62
Author(s):  
Anik Gomes ◽  
Jahangir Alam ◽  
Ghulam Murtaza ◽  
Tahmina Sultana ◽  
Efstratios E. Tzirtzilakis ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Friction Coefficient ◽  
Skin Friction ◽  
Stretching Sheet ◽  
Skin Friction Coefficient ◽  
Slip Conditions ◽  
Unsteady Stretching Sheet ◽  
Biomagnetic Fluid ◽  
Aligned Magnetic Field

The aim of the present study is to analyze the effects of aligned magnetic field and radiation on biomagnetic fluid flow and heat transfer over an unsteady stretching sheet with various slip conditions. The magnetic field is assumed to be sufficiently strong enough to saturate the ferrofluid, and the variation of magnetization is approximated by a linear function of temperature difference. The governing boundary layer equations with boundary conditions are simplified by suitable transformations. Numerical solution is obtained by using the bvp4c function technique in MATLAB software. The numerical results are derived for the velocity, temperature, the skin friction coefficient, and the rate of heat transfer. The evaluated results are compared with analytical study documented in scientific literature. The present investigation illustrates that the fluid velocity is decreased with the increasing values of radiation parameter, magnetic parameter, and ferromagnetic interaction parameter, though is increased as the Prandtl number, Grashof number, permeable parameter and thermal slip parameter are increased. In this investigation, the suction/injection parameter had a good impact on the skin friction coefficient and the rate of heat transfer.

scholarly journals The Magneto-Natural Convection Flow of a Micropolar Hybrid Nanofluid Over a Vertical Plate Saturated in a Porous Medium

Fluids ◽  
2021 ◽  
Vol 6 (6) ◽  
pp. 202
Author(s):  
A. Mahdy ◽  
E. R. El-Zahar ◽  
A. M. Rashad ◽  
W. Saad ◽  
H. S. Al-Juaydi
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Nusselt Number ◽  
Friction Coefficient ◽  
Skin Friction ◽  
Skin Friction Coefficient ◽  
Hybrid Nanofluid ◽  
Non Linear ◽  
The Magnetic Field ◽  
Linear Odes

In this study, we investigate the convective flow of a micropolar hybrid nanofluid through a vertical radiating permeable plate in a saturated porous medium. The impact of the presence or absence of the internal heat generation (IHG) in the medium is examined as well as the impacts of the magnetic field and thermal radiation. We apply similarity transformations to the non-dimensionalized equations and render them as a system of non-linear ODEs (Ordinary Differential Equations) subject to appropriate boundary conditions. This system of non-linear ODEs is solved by an adaptive mesh transformation Chebyshev differential quadrature method. The influence of the governing parameters on the temperature, microrotation and velocity is examined. The skin friction coefficient and the Nusselt number are tabulated. We determine that the skin friction coefficient and heat transport rate increase with the increment in the magnetic field. Moreover, the increment in the micropolarity and nanoparticle volume fraction enhances the skin friction coefficient and the Nusselt number. We also conclude that the IHG term improved the flow of the hybrid nanofluid. Finally, our results indicate that employing a hybrid nanofluid increases the heat transfer compared with that in pure water and a nanofluid.

scholarly journals Can the Local Bubble explain the radio background?

2021 ◽  
Vol 502 (2) ◽  
pp. 2807-2814
Author(s):  
Martin G H Krause ◽  
Martin J Hardcastle
Keyword(s):  
Magnetic Field ◽  
Energy Density ◽  
Radio Emission ◽  
Magnetic Energy ◽  
Cosmic Ray ◽  
Observational Constraints ◽  
Local Bubble ◽  
Magnetic Energy Density ◽  
Magnetic Field Model ◽  
Radio Background

ABSTRACT The ARCADE 2 balloon bolometer along with a number of other instruments have detected what appears to be a radio synchrotron background at frequencies below about 3 GHz. Neither extragalactic radio sources nor diffuse Galactic emission can currently account for this finding. We use the locally measured cosmic ray electron population, demodulated for effects of the Solar wind, and other observational constraints combined with a turbulent magnetic field model to predict the radio synchrotron emission for the Local Bubble. We find that the spectral index of the modelled radio emission is roughly consistent with the radio background. Our model can approximately reproduce the observed antenna temperatures for a mean magnetic field strength B between 3 and 5 nT. We argue that this would not violate observational constraints from pulsar measurements. However, the curvature in the predicted spectrum would mean that other, so far unknown sources would have to contribute below 100 MHz. Also, the magnetic energy density would then dominate over thermal and cosmic ray electron energy density, likely causing an inverse magnetic cascade with large variations of the radio emission in different sky directions as well as high polarization. We argue that this disagrees with several observations and thus that the magnetic field is probably much lower, quite possibly limited by equipartition with the energy density in relativistic or thermal particles (B = 0.2−0.6 nT). In the latter case, we predict a contribution of the Local Bubble to the unexplained radio background at most at the per cent level.

Impact of viscosity variation on oblique flow of Cu–H2O nanofluid

2017 ◽  
Vol 232 (5) ◽  
pp. 622-631 ◽  
Author(s):  
R Tabassum ◽  
Rashid Mehmood ◽  
O Pourmehran ◽  
NS Akbar ◽  
M Gorji-Bandpy
Keyword(s):  
Heat Flux ◽  
Friction Coefficient ◽  
Skin Friction ◽  
Volume Fraction ◽  
Variable Viscosity ◽  
Solid Volume Fraction ◽  
Local Heat ◽  
Skin Friction Coefficient ◽  
Viscosity Parameter ◽  
Local Heat Flux

The dynamic properties of nanofluids have made them an area of intense research during the past few decades. In this article, flow of nonaligned stagnation point nanofluid is investigated. Copper–water based nanofluid in the presence of temperature-dependent viscosity is taken into account. The governing nonlinear coupled ordinary differential equations transformed by partial differential equations are solved numerically by using fourth-order Runge–Kutta–Fehlberg integration technique. Effects of variable viscosity parameter on velocity and temperature profiles of pure fluid and copper–water nanofluid are analyzed, discussed, and presented graphically. Streamlines, skin friction coefficients, and local heat flux of nanofluid under the impact of variable viscosity parameter, stretching ratio, and solid volume fraction of nanoparticles are also displayed and discussed. It is observed that an increase in solid volume fraction of nanoparticles enhances the magnitude of normal skin friction coefficient, tangential skin friction coefficient, and local heat flux. Viscosity parameter is found to have decreasing effect on normal and tangential skin friction coefficients whereas it has a positive influence on local heat flux.

The effect of radiation on free convective flow and mass transfer past a vertical isothermal cone surface with chemical reaction in the presence of a transverse magnetic field

2004 ◽  
Vol 82 (6) ◽  
pp. 447-458 ◽  
Author(s):  
A A Afify
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Boundary Conditions ◽  
Chemical Reaction ◽  
Transverse Magnetic Field ◽  
Convective Flow ◽  
Transverse Magnetic ◽  
Skin Friction Coefficient ◽  
Free Convective Flow ◽  
Cone Surface

The effects of radiation and chemical reactions, in the presence of a transverse magnetic field, on free convective flow and mass transfer of an optically dense viscous, incompressible, and electrically conducting fluid past a vertical isothermal cone surface are investigated. The nonlinear boundary-layer equations with the boundary conditions are transferred by a similarity transformation into a system of nonlinear ordinary differential equations with the appropriate boundary conditions. Furthermore, the similarity equations are solved numerically by using a fourth-order Runge–Kutta scheme with the shooting method. Numerical results for the skin-friction coefficient, the local Nusselt number, the local Sherwood number are given; as well, the velocity, temperature, and concentration profiles are presented for a Prandtl number of 0.7, the chemical-reaction parameter, the order of the reaction, the radiation parameter, the Schmidt number, the magnetic parameter, and the surface temperature parameter. PACS No.: 47.70.Fw

Sign in / Sign up

Export Citation Format

Share Document