2019_programme: THREE-DIMENSIONAL FINITE ELEMENT MODELING TECHNIQUES FOR UNDERWATER ACOUSTIC SCATTERING SIMULATIONS



  • Session: 17. Modeling techniques for underwater acoustic scattering and propagation
    Organiser(s): Gunderson Aaron, Isakson Marcia
  • Lecture: THREE-DIMENSIONAL FINITE ELEMENT MODELING TECHNIQUES FOR UNDERWATER ACOUSTIC SCATTERING SIMULATIONS
    Paper ID: 861
    Author(s): Gunderson Aaron, Isakson Marcia, Bonomo Anthony
    Presenter: Gunderson Aaron
    Presentation type: oral
    Abstract: Finite element (FE) modeling is a technique ideally suited for the evaluation and prediction of acoustic scattering and propagation in complicated underwater environments, but requires consideration to keep the problem computationally feasible and efficient when solving over long ranges. Two-dimensional FE solvers are often preferred for efficiency, but are limited to symmetric targets and environments. This work will demonstrate a number of techniques for three-dimensional (3D) FE modeling which facilitate highly accurate evaluation of large-scale 3D scattering solutions from elastic targets in complicated ocean environments. A recently developed numerical Green’s function determination technique allows the 3D FE domain to be kept small, while capturing far-field scattering results through the Helmholtz-Kirchhoff integral. Analytic forms of Green’s functions are generally known for only a set of simple, canonical environments, and approximations are often applied for more general problems. By determining Green’s functions numerically, analytic forms need not be known or imposed ahead of time, and may be determined accurately. A nontraditional scattering formulation is also adopted, which has been shown to improve FE model accuracy in the context of seafloor interface environments. This work will also explore the use of tapered plane wave approaches, Floquet-Bloch formulations, and other approximations within simulations involving targets in a rough or variable interface environment. A 3D model of target scattering in complex seafloor environments which applies these various techniques can be both efficient and accurate, and may strongly aid with underwater object detection and characterization. This work has been supported by the U.S. Office of Naval Research, Ocean Acoustics division, by IR&D funding from Applied Research Laboratories: The University of Texas at Austin, and by the SMART scholarship provided by the American Society for Engineering Education.
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  • Corresponding author: Dr Gunderson Aaron
    Affiliation: Applied Research Laboratories: The University of Texas at Austin
    Country: United States
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