Modeling Of Electromagnetic Problems Research Articles

Using edge elements for modeling of 3-D magnetodynamic problem via a subproblem method

Introduction: The mathematical modeling of electromagnetic problems in electrical devices are often presented by Maxwell’s equations and constitutive material laws. These equations are partial differential equations linked to fields and their sources. In order to solve these equations and simulate the distribution of magnetic fields and eddy current losses of electromagnetic problems, a subproblem method for modeling a 3-D magnetodymic problem with the b-conformal formulation is proposed.
 Methods: In this paper, the subproblem method with using edge finite elements is proposed for coupling subproblems via several steps to treat and deal with some troubles regarding to electromagnetic problems that gets quite difficulties when directly applying a finite element method. In the strategy subproblem method, it allows a complete problem to define into several subproblems with adapted dimensions. Each subproblem can be solved on its independent domain and mesh without performing in whole domain or mesh. This easily supports meshing and decreases computing time.
 Results: The obtained results, the subproblem method with edge elements indicates magnetic flux densities and the eddy current losses in the conducting region. The computed results is also compared with the measured results done by other authors. This can be shown that there is a very good agreement.
 Conclusion: The validated method has been successfully applied to a practical test problem (TEAM Problem 7).

Large-scale 3D geoelectromagnetic modeling using parallel adaptive high-order finite element method

We have investigated the use of the adaptive high-order finite-element method (FEM) for geoelectromagnetic modeling. Because high-order FEM is challenging from the numerical and computational points of view, most published finite-element studies in geoelectromagnetics use the lowest order formulation. Solution of the resulting large system of linear equations poses the main practical challenge. We have developed a fully parallel and distributed robust and scalable linear solver based on the optimal block-diagonal and auxiliary space preconditioners. The solver was found to be efficient for high finite element orders, unstructured and nonconforming locally refined meshes, a wide range of frequencies, large conductivity contrasts, and number of degrees of freedom (DoFs). Furthermore, the presented linear solver is in essence algebraic; i.e., it acts on the matrix-vector level and thus requires no information about the discretization, boundary conditions, or physical source used, making it readily efficient for a wide range of electromagnetic modeling problems. To get accurate solutions at reduced computational cost, we have also implemented goal-oriented adaptive mesh refinement. The numerical tests indicated that if highly accurate modeling results were required, the high-order FEM in combination with the goal-oriented local mesh refinement required less computational time and DoFs than the lowest order adaptive FEM.

Numerical simulation of electromagnetic acoustic transducers using distributed point source method

In spite of many advances in analytical and numerical modeling techniques for solving different engineering problems, an efficient solution technique for wave propagation modeling of an electromagnetic acoustic transducer (EMAT) system is still missing. Distributed point source method (DPSM) is a newly developed semi-analytical technique developed since 2000 by Placko and Kundu (2007) [12] that is very powerful and straightforward for solving various engineering problems, including acoustic and electromagnetic modeling problems. In this study DPSM has been employed to model the Lorentz type EMAT with a meander line and flat spiral type coil. The problem of wave propagation has been solved and eddy currents and Lorentz forces have been calculated. The displacement field has been obtained as well. While modeling the Lorentz force the effect of dynamic magnetic field has been considered that most current analyses ignore. Results from this analysis have been compared with the finite element method (FEM) based predictions. It should be noted that with the current state of knowledge this problem can be solved only by FEM.

Perfect electromagnetic conductor medium

AbstractThis article presents a review of a novel concept in electromagnetics, the Perfect Electromagnetic Conductor (PEMC). In the Minkowskian representation of the material response to electromagnetic fields, PEMC corresponds to the axion part of the constitutive tensor. From the electrical engineering point of view, PEMC is a generalization of the perfect electric conductor (PEC) and perfect magnetic conductor (PMC) materials which are useful concepts as ideal boundaries in the modeling of electromagnetic problems. PEMC is characterized by a pseudoscalar, admittance‐type parameter M, with limits 1/M → (PEC) and M → (PMC). This paper discusses how the PECM medium as a boundary or in particulate form generalizes earlier known electromagnetic problems (reflection, scattering, materials modeling, waveguides, resonators, image principles). The main effect of PEMC boundary is to rotate the polarization plane of the reflected electric field vector. Also practical realization aspects of a PEMC medium are discussed in the paper.

Perfect electromagnetic conductor medium

This article presents a review of a novel concept in electromagnetics, the Perfect Electromagnetic Conductor (PEMC). In the Minkowskian representation of the material response to electromagnetic fields, PEMC corresponds to the axion part of the constitutive tensor. From the electrical engineering point of view, PEMC is a generalization of the perfect electric conductor (PEC) and perfect magnetic conductor (PMC) materials which are useful concepts as ideal boundaries in the modeling of electromagnetic problems. PEMC is characterized by a pseudoscalar, admittance-type parameter M, with limits 1/M (PEC) and M (PMC). This paper discusses how the PECM medium as a boundary or in particulate form generalizes earlier known electromagnetic problems (reflection, scattering, materials modeling, waveguides, resonators, image principles). The main effect of PEMC boundary is to rotate the polarization plane of the reflected electric field vector. Also practical realization aspects of a PEMC medium are discussed in the paper.

Physical modeling of systems involving electromagnetic heating of materials

The technique of physical scale modeling of electromagnetic problems that include heat generation is described. The scaling groups required for modeling, which depend on the ratio of conduction to displacement currents, are derived from simple physical arguments which are suitable for presentation to undergraduates in a first course on Mawell's equations. The modeling of some practical problems is considered, and the approximations that must be made to the scaling groups to solve these problems are discussed. Three special cases are considered in some depth. In the first case conduction current greatly dominates the current flow in the full-scale system (such heating can be referred to as resistive heating). In the second case both conduction and displacement currents are significant. In the third case conduction current is much greater than displacement current and the system dimensions are comparable to or greater than the wavelength and depth of penetration. >

The Finite-Difference Time-Domain (FD-TD) Method for Electromagnetic Scattering and Interaction Problems

The formulation and recent applications of the finite-difference time-domain (FD-TD) method for the numerical modeling of electromagnetic scattering and interaction problems are considered. It is shown that improvements in FD-TD modeling concepts and software implementation often make it a preferable choice for structures which cannot be easily treated by conventional integral equations and asymptotic approaches. Recent FD-TD modeling validations in research areas including coupling to wires and wire bundles in free space and cavities, scattering from surfaces in relativistic motion, inverse scattering, and radiation condition theory, are reviewed. Finally, the advantages and disadvantages of FD-TD, and guidelines concerning when FD-TD should and should not be used in high-frequency electromagnetic modeling problems, are summarized.