A comparison of boundary integral formulations for 2D axisymmetric eddy current problems

Boundary element formulations based on a direct manipulation of the boundary integral equations, the Mueller method, and the applications of the impedance boundary condition (IBC) are compared. The basis of the comparison is primarily the numerical performance for solving the classic problem of a conducting sphere in a time harmonic field. It is shown that the Mueller formulation, despite having lower order singularities, can be significantly in error in comparison with the direct and IBC formulations. A short conducting cylinder coaxial with a short current sheet is used to test the direct and Mueller formulations at low penetration-depth values, and good results are obtained.>