Modified surface impedance boundary conditions for 3D eddy current problems

The concept of modified surface impedance boundary conditions (IBCs) is extended to three-dimensional eddy current problems. Approximate expressions for the modified surface impedances near sharp edges and corners are given. The validity of the expressions is examined by solving test problems using the method of fundamental solutions. The results given by the approximate expressions are compared with the true values of surface impedances obtained from the full region solution (i.e., without the use of IBCs), and those agree well with the latter