Abstract

This study has investigated the wave diffraction due to insular breakwater using analytical solutions based on the Fresnel integral and polynomial approximation solution of Fresnel integrals, and numerical solutions of boundary element method (BEM) based on the boundary integral equation. When using the Fresnel integrals the mathematical equations and the boundary conditions became complicated, but when using the polynomial approximation solution these things became less complex and were able to be expressed in more simple terms. Using the polynomial approximation solution also allowed for a fast approach to going through a great deal of data. The BEM allowed for the simplification of input data, the reduction of memory usage and the allowance of measuring the physical quantity within the boundary. The results of wave diffraction derived from the three methods were compared through implementation of various calculation conditions and has been expressed through graphs and contours. This study aims to provide information on how to use the polynomial approximation solution and the BEM instead of the Fresnel integrals in many practical situations and also in regions or wave fields where a great amount of calculation time is required in order to figure out wave diffraction problems.

Key words: Wave diffraction, insular breakwater, Fresnel integral, polynomial approximation solution, boundary element method.