COMPUTING FLUX INTENSITY FACTORS BY A BOUNDARY METHOD FOR ELLIPTIC-EQUATIONS WITH SINGULARITIES

A simple method for computing the flux intensity factors associated wi th the asymptotic solution of elliptic equations having a large conver gence radius in the vicinity of singular points is presented. The Pois son and Laplace equations over domains containing boundary singulariti es due to abrupt change of the boundary geometry or boundary condition s are considered. The method is based on approximating the solution by the leading terms of the local symptotic expansion, weakly enforcing boundary conditions by minimization of a norm on the domain boundary i n a least-squares sense. The method is applied to the Motz problem, re sulting in extremely accurate estimates for the flux intensity factors . It is shown that the method converges exponentially with the number of singular functions and requires a low computational cost. Numerical results to a number of problems concerned with the Poisson equation o ver an L-shaped domain, and over domains containing multiple singular points, demonstrate accurate estimates for the flux intensity factors. (C) 1998 John Wiley & Sons, Ltd.