Abstract
Underwater acoustic target scattering measurements rely on high-fidelity modeling for experimental comparison and understanding. Three-dimensional (3D) finite element models are well suited for this purpose, as they can account for arbitrary or unknown target properties and configurations/orientations within complex and asymmetrical seafloor environments. High acoustic frequencies and large physical distances associated with in situ scattering measurements pose challenges to 3D modeling efforts in terms of model sizes and runtimes. Certain model considerations must be made to keep the 3D model computationally efficient, yet accurate in predictive capability. Numerically determined Green’s functions are demonstrated to permit 3D model reduction, while still preserving far-field scattering prediction capability through the Helmholtz–Kirchhoff integral. By determining Green’s functions within the model, they need not be known or estimated for complex ocean environments a priori. Nontraditional scattering formulations and a survey of boundary truncation methods also are explored and implemented for maximal accuracy within small 3D computational domains. Model results for canonical elastic targets within varying seafloor environments are shown and compared to theory and experimentation. [Work supported by the Strategic Environmental Research and Development Program and by the Office of Naval Research, Ocean Acoustics.]
Published Version
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