Boundary element analysis of multilayer induction problems with rotational symmetry

The problem considered is that of computing the time-harmonic eddy currents induced in a linear multilaver medium with rotational symmetry due to an aziumthal current excitation with arbitrary distribution in space. A system of one-dimensional Fredholm boundary integral equations are developed for the tangential field components at the interfaces. When discretized using boundary elements and the collocation method, a block tridiagonal matrix problem results. Application to one boundary simply connected and multiply connected exterior and interior problems as well as to a multilayer problem is demonstrated. The results are compared with analytical solutions or those obtained by other numerical methods.