Contents I. Introduction
This contribution deals with the numerical simulation of eddy currents in three-dimensional (3-D) moving rigid bodies. Such a problem arises, for example, from the modeling of electromechanical systems. We address the question of how to calculate the electromagnetic fields if the motion of the bodies is known in advance. In the presence of moving structures, we can work in Euler variables, adding a convective term in the equations or in Lagrange ones. The second choice may be, physically and computationally, more convenient if we use a method that allows to use nonmatching grids at the sliding interface. The problem of dealing with nonmatching grids has been faced for a long time (see [6] for a short overview on the subject) and the existing methods are difficult to be applied for 3-D modeling. The mortar element method (see [2] for its mathematical analysis in the Maxwell's equations framework and [4] for its first application to magnetostatics in 3-D) is a nonconforming nonoverlapping domain decomposition technique which allows for independent meshes in adjacent subdomains. The idea of the method is to weakly impose the transmission conditions at the interfaces by means of Lagrange multipliers suitably chosen to ensure optimal properties on the discrete problem. The numerical results we present here correspond to the first application of the proposed method to magnetodynamics. They constitute an encouraging step toward more realistic applications.
