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Introduction
Published in Shoogo Ueno, Tsukasa Shigemitsu, Bioelectromagnetism, 2022
Shoogo Ueno, Tsukasa Shigemitsu
When a resistor is connected to one end of a wire and an electric current flows through the wire, the current creates magnetic lines of force around the wire. Magnetic lines of force are also invisible, but when a magnet is placed near the wire, its existence is confirmed by the experience of attractive or repulsive forces in the direction of the magnetic lines of force. The space where these magnetic lines of force exist or the field where they act is called magnetic fields. Its strength is proportional to the density of the magnetic lines of force. Even if an AC power supply is used instead of a DC power supply, the distribution pattern remains the same as in the case of a DC power supply, except that the direction of the magnetic lines of force reverses corresponding to the direction of the current. The units of magnetic field strength are Newton/Weber (N/Wb) and Ampere/Meter (A/m). Magnetic flux density, which is defined as the amount of magnetic field passing through a unit cross-section area, is used in place of magnetic field. The unit for magnetic flux density is Wb/m or Tesla (T) which is equal to 104 Gauss (G). If H and B are made to be the magnetic field and the magnetic flux density, respectively, it becomes B=μH
Electromagnetic Wave Theory
Published in John R. Howell, M. Pinar Mengüç, Kyle Daun, Robert Siegel, Thermal Radiation Heat Transfer, 2020
John R. Howell, M. Pinar Mengüç, Kyle Daun, Robert Siegel
Electric displacement and magnetic induction are related to the electric and magnetic fields. Faraday’s law of induction tells us that the induced electromotive force in any closed circuit is equal to the rate of change of the magnetic flux through the circuit. This law clearly shows that the time-varying electric field will produce a time-varying magnetic field and vice versa.
DC machines
Published in William Bolton, Engineering Science, 2020
The basic principles involved in explaining the action of DC machines are: A force is exerted on a conductor in a magnetic field, which has a component at right angles to it, when a current passes through it. For a conductor of length L carrying a current I in a magnetic field of flux density B at right angles to the conductor, the force F = BIL.When a conductor moves in a magnetic field then an EMF is induced across it. The induced EMF e is equal to the rate at which the magnetic flux Φ swept through by the conductor changes (Faraday’s law) and is in such a direction as to oppose the change producing it (Lenz’s law), i.e. e = –dΦ/dt. The EMF induced in a conductor, of length L moving with a velocity v through a magnetic field with flux density B at right angles to it and the velocity, is BLv.
Non-Fourier heat and mass transfer enhancement in magnetohydrodynamic ionized fluid
Published in Waves in Random and Complex Media, 2022
Flow of an electrically conducting fluid subjected to magnetic field causes a change in magnetic flux which arises Lorentz force. This force opposes the flow and fluid experiences retardation. Such flows are termed as magneto hydrodynamics flows (MHD flows). To model such flows and related phenomenon like heat and mass transfer, Maxwell set of equations [10] and Ohm's laws are augmented with usual equation of motion of fluids. For background of modeling related to MHD flows, the studies [11, 12] can be consulted. If electrically conducting fluids are ionized or partially ionized then classical Ohm's law is insufficient to model the flows of such fluids. Therefore, several researchers have used Maxwell set of equations, generalized laws with usual equations of fluid mechanics and heat and mass transfer, for instance [13–19].
Numerical study of non-Fourier heat transfer in MHD Williamson liquid with hybrid nanoparticles
Published in Waves in Random and Complex Media, 2022
Maryam Haneef, Sayer Obaid Alharbi
The Weissenberg number determines the Williamson rheological characteristics and its impact on the velocity of the fluid particles is examined through simulations against the change of The outcome is displayed in Figure 2. This Figure demonstrates a decline in the flow of Williamson fluid for both types of nanoparticles. Thus, the Weissenberg number helps in controlling the thickness of the viscous region (see Figure 2). The distortion of lines of the applied magnetic field results a change in magnetic flux which induces the Lorentz force. This force acts opposite to the flow of the fluid and therefore, flow experiences deceleration as a consequence viscous region shrinks, and the thickness of the viscous region can be controlled through the applied magnetic field. It is also noted from simulations that Lorentz force for the flow of hybrid nanofluid has a greater magnitude than that for the flow of mono nanofluid. The influence of curvature parameter on the velocity of a fluid with mono and hybrid nanofluid is demonstrated in simulations. A decreasing behavior of velocity can be seen from simulations.
Magnetic flux flows of optical quasi binormal magnetic flows with flux density
Published in Waves in Random and Complex Media, 2021
Talat Körpinar, Zeliha Körpinar, Rıdvan Cem Demırkol
The quasi magneticfluxis presented byMagnetic flux is given by With short calculations, we obtain that Quasi magnetic flux density of is presented by Moreover, flux is provided by This equation of magnetic flux is assumed to be governed by the motion of the quasi- magnetic particle and corresponding magnetic field distribution associated with the Lorentz force equation. We present its geometric dynamics equation based on the orthonormal curvilinear and anholonomic coordinates by taking into account the quasi magnetic field lines. Now, we also consider the ferromagnetic distribution on that flow to comprehend the exact dynamics of the magnetic flux surfaces and their flux densities when the Lorentz force of the governs the dynamics. For the ferromagnetic model of the Lorentz flux, we already know that Similarly, we can obtain that So, we can easily obtain