Dual extremum principles for a class of electrostatic field interface problems

Dual extremum principles (DEP), based on Arthurs’ canonical approach, are applied to solve a class of electrostatic field interface problems. To illustrate the formulation, a rectangular metal tank, half-filled with petroleum products, is considered. The electrostatic potential and field distributions inside the petroleum tank are calculated using the dual finite element method, the method of Kantoro-vich and Ritz procedure. The bounds for the system energy are computed through the dual finite element method. © 1989 Taylor & Francis Group, LLC.