A UNIFIED TRAPEZOIDAL QUADRATURE METHOD FOR SINGULAR AND HYPERSINGULAR BOUNDARY INTEGRAL OPERATORS ON CURVED SURFACES

This paper describes a locally corrected trapezoidal quadrature method for the discretization of singular and hypersingular boundary integral operators (BIOs) that arise in solving boundary value problems for elliptic partial differential equations. The quadrature is based on a uniform grid in parameter space coupled with the standard punctured trapezoidal rule. A key observation is that the error incurred by the singularity in the kernel can be expressed exactly using generalized Euler-Maclaurin formulas that involve the Riemann zeta function in 2 dimensions (2D) and the Epstein zeta functions in 3 dimensions (3D). These expansions are exploited to correct the errors via local stencils at the singular point using a novel systematic moment-fitting approach. This new method provides a unified treatment of all common BIOs (Laplace, Helmholtz, Stokes, etc.). We present numerical examples that show convergence of up to 32nd-order in 2D and 9th-order in 3D with respect to the mesh size.