Abstract
The Boundary Element Method (BEM) implemented by the Green's integral equation is used to solve wave field governed by the Laplace equation or the Helmholtz. When a singular function of Source type is used to induce the integral equation, the potential on the singular point is represented by the boundary integral. And when a singular function of potential is represented by the boundary integral.
Usually the former type of the integral equation is used in the normal problem of BEM. But in particular problems, wave field around thin structures or thin barriers, the latter type of the integral equation is useful. However the singularity of Doublet type singular function is very strong. Therefore for the Doublet type it is difficult to obtain necessary accuracy from the numerical boundary integral.
In the present paper, we investigate the accuracy of boundary integral with the trapezoidal rule and with the liner approximation for both the Source type and the Doublet type singular functions.
