Computer Implementation of Coupled Boundary Integral Equation and Finite Element Methods

摘要

This report describes a method for computing solutions to partial differential equations in unbounded regions. The differential equations and unbounded regions arise in problems such as underwater acoustic and magnetic or electric fields surrounding vehicles or instruments in the sea or air. The method couples finite element and boundary integral equation solutions to compute shock response of submarine hulls, acoustic scattering due to elastic structures, electromagnetic signatures of ships and submarines, etc. The finite element method is used in the bounded region occupied by the vehicle or instrument. In this region there may be acoustic, magnetic or electric sources and the material properties may be nonuniform. The boundary integral equation method is used in the unbounded region occupied by the surrounding sea or atmosphere. This method requires that the unbounded region be assumed to be free of sources and have uniform material properties. The coupled method produced good results for a sample problem in which the temperature distribution was computed for a two-dimensional steady state heat flow. (Author)