A numerical calculation of open boundary problem by applying the finite element method and boundary element method alternately

The finite element method (FEM) and the boundary element method (BEM), which have entirely different characteristics, are standard methods for the numerical analysis of physical phenomena described by partial differential equations. The FEM is suitable for the analysis of a complicated region that includes nonlinear materials, whereas the BEM is naturally effective for analyzing a very large region with linear characteristics. Therefore, considering the advantages in both methods, a novel algorithm for the alternate application of the FEM and the BEM to magnetic field problems with the open boundary is presented. This approach avoids the disadvantages of the typical numerical methods with the open boundary problem such as a great number of unknown values for the FEM and nonsymmetric matrix for the hybrid FE–BE method. The solution of the overall problems is obtained by iterative calculations accompanied with the new acceleration method.