We characterize the behavior of solutions to systems of boundary integral equations
associated with Laplace transmission problems in composite media consisting of
regions with polygonal boundaries. In particular we consider triple junctions, i.e.,
points at which three distinct media meet. We show that, under suitable
conditions, solutions to the boundary integral equations in the vicinity of a triple
junction are well-approximated by linear combinations of functions of the form
,
where
is the distance of the point from the junction and the powers
depend only on the material properties of the media and the angles at which their
boundaries meet. Moreover, we use this analysis to design efficient discretizations of
boundary integral equations for Laplace transmission problems in regions with triple
junctions and demonstrate the accuracy and efficiency of this algorithm with a
number of examples.
Keywords
boundary integral equations, multiple junction interfaces,
corners, singular solutions, potential theory