Predicting range-dependent underwater sound propagation from structural sources in shallow water using coupled finite element/equivalent source computations

Predictions of underwater sound propagation (USP) from structural sources in complex shallow-water environments are crucial for underwater navigation, communication, and localization. Modeling range-dependent USP in shallow water remains challenging because structural acoustic radiation is coupled with complex waveguide physics. This paper presents a coupled finite element (FE)/equivalent source (ES) computation scheme for predicting the range-dependent USP from a structural source. The scheme involves coupled vibroacoustic FE/ES analyses and waveguide-field ES computations. The former computes the structural vibration response and reproduces the structural-acoustic radiation at arbitrary spatial positions. The coupled vibroacoustic FE/ES analysis provides the input for the waveguide-field ES computations, which couple the structural-acoustic radiation with the shallow-water environment. A multilayer acoustic–elastic ES method (ESM) is developed to accommodate sound speed inhomogeneities and a range-dependent elastic seabed. Numerical simulations demonstrate the interactions of structural-acoustic radiation with two-dimensional topographies and internal solitary waves. The proposed scheme is extended to three dimensions by combining the coupled vibroacoustic FE/ES analysis with a pre-corrected fast Fourier transform-accelerated ESM. The results validate the proposed scheme and demonstrate its benchmark-quality solutions and high numerical efficiency, suggesting great application potential for optimizing the sonar performance at the preliminary design stage. •A coupled FE/ES computation for underwater sound propagation from structural sources.•The coupled FE/ES computation provides high numerical accurcay and efficienty.•The coupling between the acoustic radiation and 3D propagation effects is addressed.•A novel multilayer acoustic–elastic ESM is developed.•The validity of an effective complex density fluid is analyzed for structural sources.