scholarly journals A computational study of biomagnetic fluid flow in a channel in the presence of obstacles under the influence of the magnetic field generated by a wire carrying electric current

2018 ◽  
Author(s):  
S. Morteza Mousavi ◽  
Mousa Farhadi ◽  
Kurosh Sedighi
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Electric Current ◽  
Magnetic Force ◽  
Computational Study ◽  
Three Dimensional ◽  
Computational Domain ◽  
Recirculation Zones ◽  
Biomagnetic Fluid ◽  
The Magnetic Field

In this paper, biomagnetic fluid flow in a three-dimensional channel in the presence of obstacles and under the influence of a magnetic field is studied numerically. The magnetic field is generated by a wire carrying electric current. The mathematical model of biomagnetic fluid dynamics which is consistent with the principles of ferrohydrodynamics and magnetohydrodynamics is used for the problem formulation. A computational grid which accurately covers the magnetic force is used for the discretisation of computational domain. The flow field is studied in the different arrangements of the obstacles and diverse magnetic field strengths. The results show that the flow pattern is drastically influenced by the applied magnetic field. Applying the magnetic field causes a secondary flow that affects the velocity distribution considerably. The magnetic force also reduces the maximum axial velocity. Furthermore, the magnetic field has a considerable impact on the recirculation zones behind the obstacles. The magnetic field makes the recirculation zones smaller. This study indicates that applying the magnetic field increases the axial drag coefficients of the obstacles significantly (in a case, by 40.15%).

scholarly journals Distribution of the Magnetic Force in the Surface Layers of Sunspots

1971 ◽  
Vol 43 ◽  
pp. 505-511
Author(s):  
J. Jakimiec
Keyword(s):  
Magnetic Field ◽  
Magnetic Force ◽  
Vertical Structure ◽  
Three Dimensional ◽  
Suitable Method ◽  
Surface Layers ◽  
Magnetic Forces ◽  
Photospheric Level ◽  
The Magnetic Field

At the beginning the problem of constructing the three-dimensional magnetohydrostatic models of the photospheric layers in sunspots is discussed in some detail. It is pointed out that the construction of such models by solving the set of equations of magnetohydrostatics cannot be effectively carried out.In order to solve the difficulties a suitable method of determining the distribution of the magnetic force in sunspots from measurements of the magnetic field has been worked out. Tentative results of the computations are presented.General features of the distribution of the magnetic force in the photospheric layers of stable sunspots are discussed. It is pointed out that significant magnetic forces are necessary in the penumbra; they secure its transversal equilibrium, but are rather unimportant for its vertical structure. And it is quite probable that the magnetic field in the umbras of stable spots is nearly potential or force-free down to the photospheric level.

Magnetism and Molecular Rotation

1899 ◽  
Vol 22 ◽  
pp. 631-635
Author(s):  
Lord Kelvin
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Electromotive Force ◽  
Electromagnetic Induction ◽  
Magnetic Force ◽  
Metal Wire ◽  
Line Integral ◽  
Time Integral ◽  
Tangential Forces ◽  
The Magnetic Field

§ 1. Consider the induction of an electric current in an endless wire when a magnetic field is generated around it, For simplicity, let the wire be circular and the diameter of its section very small in comparison with that of the ring. The time-integral of the electromotive force in the circuit is 2AM, if A denote the area of the ring and M the component perpendicular to its plane, of the magnetic force coming into existence. This is true whatever be the shape of the ring, provided it is all in one plane. Now, adopting the idea of two electricities, vitreous and resinous, we must imagine an electric current of strength C to consist of currents of vitreous and resinous electricities in opposite directions, each of strength ½C. Hence the time-integrals of the opposite electromotive forces on units of the equal vitreous and resinous electricities are each equal to AM.§ 2. Substitute now for our metal wire an endless tube of non-conducting matter, vitreously electrified, and filled with an incompressible non-conducting fluid, electrified with an equal quantity, e, of resinous electricity. The fluid and the containing tube will experience equal and opposite tangential forces, of each of which the time-integral of the line-integral round the whole circumference is eAM, if the ring be a circle of radius r; and the effect of the generation of the magnetic field will be to cause the fluid and the ring to rotate in opposite directions with moments of momentum each equal to eAMr, if neither fluid nor ring is acted on by any other force than that of the electromagnetic induction.

On the fluid behavior and stability of Ti-6Al-4V titanium alloy GMAW molten pool: Effect of the longitudinal magnetic field

2021 ◽  
pp. 2150283
Author(s):  
Chenglong Wu ◽  
Shaohua Han ◽  
Dingqi Xue ◽  
Jianbin Zhan
Keyword(s):  
Magnetic Field ◽  
Fluid Flow ◽  
Molten Pool ◽  
Longitudinal Magnetic Field ◽  
Liquid Metals ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Surface Profile ◽  
Length Change ◽  
The Magnetic Field

By establishing a three-dimensional (3D) numerical simulation of the Ti-6Al-4V Gas Metal Argon Welding (GMAW) molten pool, the molten pool’s heat transfer and fluid flow behavior under a longitudinal magnetic field were investigated. The simulation results show that when the droplet enters the molten pool, the liquid metals on the molten pool’s surface symmetrically flow towards both sides of the molten pool from different angles. With the increase of the magnetic field strengthens, the temperature gradually decreases, and the fluid flow velocity increases continuously. Besides, the magnetic field strength is correlated positively with the molten pool’s size with a certain range of 0–0.03 T. However, when the magnetic field strengthens reach 0.04 T, the magnetic field is correlated negatively with the molten pool’s size. Because the Marangoni and buoyancy begin to weaken, the molten pool’s length change occurs before the width change. Simultaneously, a sizeable velocity region appears on the left side of the molten pool. Thus, the liquid metal gathers on the left side, resulting in the weld cross-section’s asymmetry. It can conclude that only when the magnetic strengthen keeps in the range of 0–0.03 T, the longitudinal magnetic field can make the molten pool’s surface profile smooth.

scholarly journals Numerical Investigation on Magnetically Actuated Tunable Micro Liquid Lens

2020 ◽  
Vol 306 ◽  
pp. 02007
Author(s):  
Shi-Hua Wu ◽  
Gui-Ping Zhu ◽  
Hu-Lin Huang
Keyword(s):  
Magnetic Field ◽  
Direct Contact ◽  
Magnetic Force ◽  
Computational Domain ◽  
Light Refraction ◽  
Liquid Lens ◽  
Magnetically Actuated ◽  
Variable Focus ◽  
The Magnetic Field ◽  
Application Scope

In this paper, magnetically actuated tunable liquid lens is fundamentally studied to have further potential application scope in research, industrial, aeronautical and astronautical areas. The magnetic field, which is generated by a magnetic potential applied to the permanent magnet domain, distributes non-uniformly in the computational domain and generates magnetic field force to obtain the deformation of the ferrofluid droplet. Consequently, the light-transmitting droplet deforms due to direct contact with the ferrofluid droplet by a connecting channel. The combined effects of gravitational, frictional, interfacial and pressure-driven force make light-transmissive droplet to be a programmable liquid lens. The light-transmissive droplet exhibits changes in the curvature of the contour, which results in different focal lengths for realizing the variable-focus liquid lens. This work focus on the driven mechanism by the magnetic force for a better understanding. The performance is numerically studied for a magnetically actuated varifocal liquid lens by finite element method. The results are presented individually for the distribution of magnetic and flow field, and light refraction.

Study of MFM Application in Semiconductor Failure Analysis

2004 ◽  
Author(s):  
Way-Jam Chen ◽  
Lily Shiau ◽  
Ming-Ching Huang ◽  
Chia-Hsing Chao
Keyword(s):  
Magnetic Field ◽  
Failure Analysis ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Current Flow ◽  
Force Microscopy ◽  
The Magnetic Field ◽  
A Current

Abstract In this study we have investigated the magnetic field associated with a current flowing in a circuit using Magnetic Force Microscopy (MFM). The technique is able to identify the magnetic field associated with a current flow and has potential for failure analysis.

scholarly journals The effect of simplifications of a numerical mesh on the results of electromagnetic analysis of the Nuclotron-type cable

2018 ◽  
Vol 177 ◽  
pp. 08004
Author(s):  
Łukasz Tomków
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Current Density ◽  
Electric Current Density ◽  
Electromagnetic Analysis ◽  
First Case ◽  
Single Region ◽  
The Magnetic Field

The model of a single Nuclotron-type cable is presented. The goal of this model is to assess the behaviour of the cable under different loads. Two meshes with different simplifications are applied. In the first case, the superconductor in the cable is modelled as single region. Second mesh considers individual strands of the cable. The significant differences between the distributions of the electric current density obtained with both models are observed. The magnetic field remains roughly similar.

CHOICE OF CONDITIONS FOR MHD SIMULATIONS ABOVE THE ACTIVE REGION, ALLOWING THE STUDY OF THE SOLAR FLARE MECHANISM

2021 ◽  
Vol 44 ◽  
pp. 92-95
Author(s):  
A.I. Podgorny ◽  
◽  
I.M. Podgorny ◽  
A.V. Borisenko ◽  
N.S. Meshalkina ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Solar Flare ◽  
Magnetic Energy ◽  
Solar Radius ◽  
Computational Domain ◽  
Mhd Simulations ◽  
Flare Energy ◽  
Numerical Instabilities ◽  
The Magnetic Field

Primordial release of solar flare energy high in corona (at altitudes 1/40 - 1/20 of the solar radius) is explained by release of the magnetic energy of the current sheet. The observed manifestations of the flare are explained by the electrodynamical model of a solar flare proposed by I. M. Podgorny. To study the flare mechanism is necessary to perform MHD simulations above a real active region (AR). MHD simulation in the solar corona in the real scale of time can only be carried out thanks to parallel calculations using CUDA technology. Methods have been developed for stabilizing numerical instabilities that arise near the boundary of the computational domain. Methods are applicable for low viscosities in the main part of the domain, for which the flare energy is effectively accumulated near the singularities of the magnetic field. Singular lines of the magnetic field, near which the field can have a rather complex configuration, coincide or are located near the observed positions of the flare.

scholarly journals Magnetic Field Structure of Star Forming Regions: VLBI Spectral Line Results

1984 ◽  
Vol 110 ◽  
pp. 333-334
Author(s):  
J.A. Garcia-Barreto ◽  
B. F. Burke ◽  
M. J. Reid ◽  
J. M. Moran ◽  
A. D. Haschick
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Aperture Synthesis ◽  
Stokes Parameters ◽  
Hii Region ◽  
Star Forming ◽  
Star Forming Regions ◽  
Vlbi Observations ◽  
The Magnetic Field ◽  
Synthesis Experiment

Magnetic fields play a major role in the general dynamics of astronomical phenomena and particularly in the process of star formation. The magnetic field strength in galactic molecular clouds is of the order of few tens of μG. On a smaller scale, OH masers exhibit fields of the order of mG and these can probably be taken as representative of the magnetic field in the dense regions surrounding protostars. The OH molecule has been shown to emit highly circular and linearly polarized radiation. That it was indeed the action of the magnetic field that would give rise to the highly polarized spectrum of OH has been shown by the VLBI observations of Zeeman pairs of the 1720 and 6035 MHz by Lo et. al. and Moran et. al. VLBI observations of W3 (OH) revealed that the OH emission was coming from numerous discrete locations and that all spots fell within the continuum contours of the compact HII region. The most detailed VLBI aperture synthesis experiment of the 1665 MHz emission from W3 (OH) was carried out by Reid et. al. who found several Zeeman pairs and a characteristic maser clump size of 30 mas. In this work, we report the results of a 5 station VLBI aperture synthesis experiment of the 1665 MHz OH emission from W3 (OH) with full polarization information. We produced VLBI synthesis maps of all Stokes parameters of 16 spectral features that showed elliptical polarization. The magnitude and direction of the magnetic field have been obtained by the detection of 7 Zeeman pairs. The three dimensional orientation of the magnetic field can be obtained, following the theoretical arguments of Goldreich et. al., from the observation of π and σ components.

scholarly journals INCREASING THE EFFICIENCY OF MULTY-VARIANT CALCULATIONS OF ELECTROMAGNETIC FIELD DISTRIBUTION IN MATRIX OF A POLYGRADIENT SEPARATOR

2021 ◽  
Author(s):  
Jasim Mohmed Jasim Jasim ◽  
Iryna Shvedchykova ◽  
Igor Panasiuk ◽  
Julia Romanchenko ◽  
Inna Melkonova
Keyword(s):  
Magnetic Field ◽  
Field Distribution ◽  
Three Dimensional ◽  
Magnetic Potential ◽  
Geometric Parameters ◽  
Two Dimensional ◽  
Air Gaps ◽  
Vector Magnetic Potential ◽  
Electromagnetic Separator ◽  
The Magnetic Field

An approach is proposed to carry out multivariate calculations of the magnetic field distribution in the working gaps of a plate polygradient matrix of an electromagnetic separator, based on a combination of the advantages of two- and three-dimensional computer modeling. Two-dimensional geometric models of computational domains are developed, which differ in the geometric dimensions of the plate matrix elements and working air gaps. To determine the vector magnetic potential at the boundaries of two-dimensional computational domains, a computational 3D experiment is carried out. For this, three variants of the electromagnetic separator are selected, which differ in the size of the working air gaps of the polygradient matrices. For them, three-dimensional computer models are built, the spatial distribution of the magnetic field in the working intervals of the electromagnetic separator matrix and the obtained numerical values of the vector magnetic potential at the boundaries of the computational domains are investigated. The determination of the values of the vector magnetic potential for all other models is carried out by interpolation. The obtained values of the vector magnetic potential are used to set the boundary conditions in a computational 2D experiment. An approach to the choice of a rational version of a lamellar matrix is substantiated, which provides a solution to the problem according to the criterion of the effective area of the working area. Using the method of simple enumeration, a variant of the structure of a polygradient matrix with rational geometric parameters is selected. The productivity of the electromagnetic separator with rational geometric parameters of the matrix increased by 3–5 % with the same efficiency of extraction of ferromagnetic inclusions in comparison with the basic version of the device

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