Electrically driven cylindrical free shear flows under an axial uniform magnetic field

2021 ◽  
Vol 57 (2) ◽  
pp. 229-250
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Applied Field ◽  
Uniform Magnetic Field ◽  
Shear Flows ◽  
Hartmann Number ◽  
Induced Magnetic Field ◽  
Free Shear Layers ◽  
Moderate Magnetic Field ◽  
Almost All

We consider a mathematical model of two-dimensional electrically driven laminar axisymmetric circular free shear flows in a cylindrical vessel under the action of an applied axial uniform magnetic field. The mathematical approach is based on the studies by J.C.R. Hunt and W.E. Williams (J. Fluid. Mech., 31, 705, 1968). We solve a system of stationary partial differential equations with two unknown functions of velocity and induced magnetic field. The flows are generated as a result of the interaction of the electric current injected into the liquid and the applied field using one or two pairs of concentric annular electrodes located apart on the end walls. Two lateral free shear layers and two Hartmann layers on the end walls and a quasi-potential flow core between them emerge when the Hartmann number Ha >> 1. As a result, almost all injected current passes through these layers. Depending on the direction of the current injection, coinciding or two counter flows between the end walls are realized. The Hartmann number varies in a range from 2 to 300. When a moderate magnetic field (Ha = 50) is reached, the flow rate and the induced magnetic field flux cease to depend on the magnitude of the applied field but depend on the injected electric current value. Increasing magnetic field leads only to inner restructuring of the flows. Redistributions of velocities and induced magnetic fields, electric current density versus Hartmann number are analyzed. Figs 18, Refs 21.

scholarly journals Magnetohydrodynamic Flow of a Bingham Fluid in a Vertical Channel: Mixed Convection

Fluids ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 154
Author(s):  
Alessandra Borrelli ◽  
Giulia Giantesio ◽  
Maria Cristina Patria
Keyword(s):  
Magnetic Field ◽  
Mixed Convection ◽  
Uniform Magnetic Field ◽  
Hartmann Number ◽  
Reverse Flow ◽  
Vertical Channel ◽  
Bingham Fluid ◽  
Induced Magnetic Field ◽  
Bingham Number ◽  
External Uniform Magnetic Field

In this paper, we describe our study of the mixed convection of a Boussinesquian Bingham fluid in a vertical channel in the absence and presence of an external uniform magnetic field normal to the walls. The velocity, the induced magnetic field, and the temperature are analytically obtained. A detailed analysis is conducted to determine the plug regions in relation to the values of the Bingham number, the buoyancy parameter, and the Hartmann number. In particular, the velocity decreases as the Bingham number increases. Detailed considerations are drawn for the occurrence of the reverse flow phenomenon. Moreover, a selected set of diagrams illustrating the influence of various parameters involved in the problem is presented and discussed.

MHD natural convection of Cu/H2O nanofluid in a horizontal semi-cylinder with a local triangular heater

2018 ◽  
Vol 28 (12) ◽  
pp. 2979-2996 ◽  
Author(s):  
A.S. Dogonchi ◽  
Mikhail A. Sheremet ◽  
Ioan Pop ◽  
D.D. Ganji
Keyword(s):  
Magnetic Field ◽  
Rayleigh Number ◽  
Free Convection ◽  
Shape Factor ◽  
Uniform Magnetic Field ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Horizontal Cylinder ◽  
Content Type ◽  
Nanoparticles Volume Fraction

Purpose The purpose of this study is to investigate free convection of copper-water nanofluid in an upper half of circular horizontal cylinder with a local triangular heater under the effects of uniform magnetic field and cold cylinder shell using control volume finite element method (CVFEM). Design/methodology/approach Governing equations formulated in dimensionless stream function, vorticity and temperature variables using the single-phase nanofluid model with Brinkman correlation for the effective dynamic viscosity and Hamilton and Crosser model for the effective thermal conductivity have been solved numerically by CVFEM. Findings The impacts of control parameters such as the Rayleigh number, Hartmann number, nanoparticles volume fraction, local triangular heater size, shape factor on streamlines and isotherms as well as local and average Nusselt numbers have been examined. The outcomes indicate that the average Nusselt number is an increasing function of the Rayleigh number, shape factor and nanoparticles volume fraction, while it is a decreasing function of the Hartmann number. Originality/value A complete study of the free convection of copper-water nanofluid in an upper half of circular horizontal cylinder with a local triangular heater under the effects of uniform magnetic field and cold cylinder shell using CVFEM is addressed.

Observation of soft glassy behavior in a magnetic colloid exposed to an external magnetic field

Soft Matter ◽  
2020 ◽  
Vol 16 (30) ◽  
pp. 7126-7136
Author(s):  
Sithara Vinod ◽  
Philip J. Camp ◽  
John Philip
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Applied Field ◽  
Uniform Magnetic Field ◽  
Volume Fraction ◽  
High Rate ◽  
Glassy Behavior ◽  
Low Volume

Microstructures (viewed in a direction perpendicular and parallel to the applied field) responsible for soft glassy behavior in a ferrofluid of low volume fraction when a uniform magnetic field is applied at a sufficiently high rate.

Stokes flow of a conducting fluid past an axially symmetric body in the presence of a uniform magnetic field

1960 ◽  
Vol 9 (3) ◽  
pp. 473-477 ◽  
Author(s):  
I-Dee Chang
Keyword(s):  
Magnetic Field ◽  
Stokes Flow ◽  
Uniform Magnetic Field ◽  
Hartmann Number ◽  
Magnetic Effect ◽  
Symmetric Body ◽  
Axially Symmetric ◽  
Low Reynolds Number Flow ◽  
Reynolds Number Flow ◽  
Number Flow

Low Reynolds number flow of an incompressible fluid past an axially symmetric body in the presence of a uniform magnetic field is studied using a perturbation method. It is found that for small Hartmann number M an approximate drag formula is given by $ D^ \prime = D^\prime_0 \left(1 + \frac {D^\prime_0} {16\pi \rho vaU}M\right) + O(M^2),$ where D′0 is the Stokes drag for flow with no magnetic effect.

MHD flow in a rectangular duct with pairs of conducting and non-conducting walls in the presence of a non-uniform magnetic field

1980 ◽  
Vol 96 (2) ◽  
pp. 335-353 ◽  
Author(s):  
Richard J. Holroyd
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Reynolds Number ◽  
Uniform Magnetic Field ◽  
Hartmann Number ◽  
Mhd Flow ◽  
Magnetic Reynolds Number ◽  
Rectangular Duct ◽  
Mean Velocity ◽  
Side Walls

A theoretical and experimental study has been carried out on the flow of a liquid metal along a straight rectangular duct, whose pairs of opposite walls are highly conducting and insulating, situated in a planar non-uniform magnetic field parallel to the conducting walls. Magnitudes of the flux density and mean velocity are taken to be such that the Hartmann numberMand interaction parameterNhave very large values and the magnetic Reynolds number is extremely small.The theory qualitatively predicts the integral features of the flow, namely the distributions along the duct of the potential difference between the conducting walls and the pressure. The experimental results indicate that the velocity profile is severely distorted by regions of non-uniform magnetic field with fluid moving towards the conducting walls; even though these walls are very good conductors the flow behaves more like that in a non-conducting duct than that predicted for a duct with perfectly conducting side walls.

Transport coefficients for a two-temperature equal-mass plasma in a uniform magnetic field

1994 ◽  
Vol 52 (2) ◽  
pp. 309-319 ◽  
Author(s):  
S. Y. Abdul-Rassak ◽  
E. W. Laing
Keyword(s):  
Magnetic Field ◽  
Heat Flux ◽  
Electric Current ◽  
Uniform Magnetic Field ◽  
Transport Coefficients ◽  
Equal Mass ◽  
Temperature Ratio ◽  
Fokker Planck Equations ◽  
Two Temperature ◽  
Fokker Planck

Transport coefficients for electric current and heat flux have been calculated for a two-temperature equal-mass plasma for several values of the temperature ratio R in the range 1 < R ≤ 100. Transport coefficients have been obtained using the linearized Fokker—Planck equations.

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