Fast multipole boundary element for acoustic analysis of adhered sound-absorbing materials under seafloor reflection condition

Abstract

This study develops an efficient computational framework for analyzing the acoustic behavior of structures coated with sound-absorbing materials in shallow water environments, explicitly accounting for seafloor reflection effects. Geometric modeling is carried out using isogeometric analysis with Catmull–Clark subdivision surfaces, ensuring high geometric fidelity. The isogeometric boundary element method (IGA-BEM) is then formulated with half-space fundamental solutions to incorporate both impedance boundary conditions of absorbing surfaces and reflection from the seabed. To overcome the computational challenges associated with fully populated system matrices, the fast multipole method (FMM) is integrated to achieve significant reductions in memory usage and computation time. Numerical experiments involving a spherical model and a submarine model demonstrate excellent agreement with analytical benchmarks and confirm the robustness of the proposed approach for complex geometries. The results underline the necessity of jointly considering seafloor reflection and absorbing coatings in high-accuracy ocean acoustic simulations, thereby offering a reliable and scalable tool for marine engineering applications.