A fast algorithm to compute shadow areas for Kirchhoff approximation-based underwater acoustic scattering simulation

Abstract

Kirchhoff approximation method is a fast underwater acoustic scattering numerical method which adaptive to engineering application. Shadow areas calculation is one of the most important factors for computational efficiency. In this paper, several existing shadow domain calculation methods for underwater acoustic numerical simulation based on Kirchhoff approximation are introduced. On this basis, a fast sheltering method based on the linked-list search algorithm is proposed. Linked-list search algorithm uses element geometric center to express the element space position and projects the geometric center on incident wave plane along the incident sound ray. And linked-list relationship of elements is established by dividing background mesh cell on the screen. The algorithm achieves fast calculation by using linked-list relationship and optimizing the calculation path. Linked-list search algorithm and all-pair search algorithm are compared and analyzed by an example of numerical simulation. The computational efficiency of the fast shadow domain algorithm is verified by comparing the results of the two algorithms. And the suggestions for further improving the computational efficiency of the algorithm are proposed.