Wolfgang M. Rucker

A novel formulation for 3D eddy current problems with moving bodies using a Lagrangian description and BEM-FEM coupling

This paper summarizes the theoretical background of 3D eddy current problems with moving bodies. A novel 3D formulation combining a Lagrangian description and BEM-FEM coupling is subsequently developed. The conducting and permeable bodies are described by the FEM in their respective rest frame, whereas the surrounding space is treated by the BEM in the laboratory frame. The FEM and BEM descriptions are coupled together taking into account the transformation between the different frames. The proposed formulation contains no explicit velocity terms.

Identification procedures of Preisach model

This work deals with the comparison of two identification procedures of Scalar and Vector Preisach Model. The first one is to assume a Preisach function and determine the different parameters with the knowledge of the remanence and the coercivity. The second one is to measure the Everett function directly.

Fast BEM computations with the adaptive multilevel fast multipole method

Since the storage requirements of the BEM are proportional to N/sup 2/, only relative small problems can be solved on a PC or a workstation. In this paper we present an adaptive multilevel fast multipole method for the solution of electrostatic problems with the BEM. We will show, that in practice the storage requirements and the computational costs are approximately proportional to N and therefore even large three dimensional problems can be solved on a relative small computer.

Comparison between different approaches for fast and efficient 3-D BEM computations

Fast methods like the fast multipole method or the adaptive cross approximation technique reduce the memory requirements and the computational costs of the boundary-element method (BEM) to approximately O(N). In this paper, both fast methods are applied in combination with BEM-finite-element method coupling to nonlinear magnetostatic problems.

Augmented reality in teaching of electrodynamics

Purpose – The purpose of this paper is to present an application of augmented reality (AR) in the context of teaching of electrodynamics. The AR visualization technique is applied to electromagnetic fields. Carrying out of numerical simulations as well as preparation of the AR display is shown. Presented examples demonstrate an application of this technique in teaching of electrodynamics.Design/methodology/approach – The 3D electromagnetic fields are computed with the finite element method (FEM) and visualized with an AR display.Findings – AR is a vivid method for visualization of electromagnetic fields. Students as well as experts can easily connect the characteristics of the fields with the physical object.Research limitations/implications – The focus of the presented work has been on an application of AR in a lecture room. Then, easy handling of a presentation among with low‐hardware requirements is important.Practical implications – The presented approach is based on low‐hardware requirements. Hence, ...

Efficient integral equation method for the solution of 3-D magnetostatic problems

Nonlinear three-dimensional (3-D) magnetostatic field problems are solved using integral equation methods (IEM). Only the nonlinear material itself has to be discretized. This results in a system of nonlinear equations with a relative small number of unknowns. To keep computational costs low the fully dense system matrix is compressed with the fast multipole method. The accuracy of the applied indirect IEM formulation is improved significantly by the use of a difference field concept and a special treatment of singularities at edges. An improved fixed point solver is used to ensure convergence of the nonlinear problem.

Parallelization of a Fast Multipole Boundary Element Method with Cluster OpenMP

Parallelization of a boundary element method for the solution of problems, which are based on a Laplace equation, is considered. The fast multipole method is applied to compress the belonging linear system of equations. The well-known parallelization standard OpenMP is used on shared memory computers and the new standard Cluster OpenMP is used on computer clusters. Both standards are based on multithreading and exploit multicore processors very efficiently. Cluster OpenMP is an enhancement of OpenMP. There, multiprocessing on a computer cluster is hidden by virtual threads, which use a virtual shared memory on a distributed memory computer.

Preconditioned fast adaptive multipole boundary-element method

The application of the fast multipole method reduces the computational costs and the memory requirements in boundary-element method (BEM) computations from O(N/sup 2/) to approximately O(N). The computation of the near-field interactions can be done very efficiently, when all conventional BEM integrations are stored in one sparse matrix. Furthermore, we will show, how the system of linear equations can be preconditioned, when the fast multipole method is used, and how the preconditioner reduces the computational costs significantly.

BEM computations using the fast multipole method in combination with higher order elements and the Galerkin method

A new approach to the adaptive multilevel fast multipole method in combination with higher order elements and the Galerkin method is presented. As the computational costs and the memory requirements are approximately proportional to the number of unknowns, very large static problems with complex geometrical configuration can be solved on a small computer.

Fast field computations with the fast multipole method

The application of the fast multipole method reduces the computational costs and the memory requirements of the boundary element method from O(N2) to approximately O(N). In this paper we present that the computational costs can be strongly shortened, when the multipole method is not only used for the solution of the system of linear equations but also for the field computation in arbitrary points.