2019_programme: PREDICTING INTERNAL WAVE PACKET CHARACTERISTICS AND ACOUSTIC SIGNAL COHERENCE

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  • Session: 20. Sonar performance modeling and verification. Applications to active and passive sonar
    Organiser(s): Colin Mathieu, Prior Mark, Heaney Kevin, Ellis Dale
  • Lecture: PREDICTING INTERNAL WAVE PACKET CHARACTERISTICS AND ACOUSTIC SIGNAL COHERENCE [invited]
    Paper ID: 982
    Author(s): Duda Timothy F, Newhall Arthur E, Helfrich Karl R, Zhang Weifeng G, Lin Ying-Tsong, Lermusiaux Pierre F J
    Presenter: Duda Timothy
    Presentation type: oral
    Abstract: A handful of experiments, theoretical studies and simulation studies have shown that packets of nonlinear internal waves, which are commonly found in shallow water areas, can have strong impacts on propagating sound. Impacts include rapid changes in the temporal and spatial coherence of the sound, and the occurrence of strongly focused sound accompanied by shadow zones with little or no sound energy. Moreover, the acoustic effects can be anisotropic, so that sound traveling in one direction geographically will have different characteristics than sound traveling another direction (for instance, along and across internal wave crests). To better apply this knowledge to the use of sound, we have developed a system of linked models to study our ability to predict the appearance of the internal wave packets, and to predict characteristics such as packet speed and direction, wave size, and wave shape. The model system links three fluid models: a primitive equation model, an internal tide model, and a nonhydrostatic internal wave model. These are linked in turn to a 3D acoustic propagation model. Output from the model system will be shown, including comparison with experimental data from the Shallow Water 2006 program. Acoustic field and acoustic parameter predictions from the system will also be shown and will be compared with experimental results.
      Download the full paper
  • Corresponding author: Dr Duda Timothy
    Affiliation: Woods Hole Oceanographic Institution
    Country: United States
    e-mail:

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