A multipole expansion-based boundary element method for axisymmetric potential problem

The multipole expansion is all approximation technique used to evaluate the potential field due to sources located in the far field. Based oil the multipole expansion, we describe a new technique to calculate the far potential field due to ring sources which arc encountered in the boundary element method (BEM) formulation of axisymmetric problems. As the sources in the near field are processed by the slower conventional BEM. it is important to maximize the amount of multipole calculations taking advantage of both interior acid exterior multipole expansions. Numerical results are presented for an axisymmetric potential test problem with Neumann and Dirichlet boundary conditions. The complexity of the proposed method remains O(N-2), which is equal to that of the conventional BEM. However, the proposed technique coupled with ail iterative solver speeds up the solution procedure. The technique is significantly advantageous when medium gild large numbers of elements are present in the domain. (C) 2003 Elsevier Ltd. All rights reserved.