UACE2017 Proceedings: Determining the Underwater Acoustic Properties of materials, with a Fluid-Filled Impedance Tube and Two Spatial-Modes Reduced-Order Model

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  • Session:
    Poster
  • Paper:
    Determining the Underwater Acoustic Properties of materials, with a Fluid-Filled Impedance Tube and Two Spatial-Modes Reduced-Order Model
  • Author(s):
    Yoav Vered, Izhak Bucher
  • Abstract:
    In this work, a novel method to characterize the underwater acoustics properties of small specimen is being derived. The method is based on the use of a reduced-order model, which is able to capture two or more propagating modes. A separation technique is used to determine the phase velocity and the complex amplitudes of the incident and reflected wave of each mode. Currently, standard tests of acoustic impedance in air-filled tubes neglects the fluid-structure interaction (FSI) under the assumption that the enclosure solid acoustic admittance can be neglected compared to that of air at low frequency. This assumption has been investigated in fluid-filled tubes and was found to be inaccurate. It was shown that at least two propagating modes are present in the tube at all frequencies. Our proposed method uses a finite liquid-filled elastic-walled tube, which is actuated at both ends and between them a specimen is located. We aim to measure the sound field along the tube axis using an array of hydrophones. The method comprises three steps: The first step of the method is the separation of the phase velocity of the participating modes under consideration. The second step is the separation of the incident and reflected wave complex amplitudes. The third step uses a Transfer Matrix based method to determine the specimen acoustic properties using the previously estimated parameters. A numerical experiment of a coupled (FSI) tube is carried to analyze the method sensitivity to measurement noise and hydrophones bias.
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Contact details

  • Contact person:
    Mr Yoav Vered
  • e-mail:
  • Affiliation:
    Faculty of Mechanical Engineering, Technion – Israel Institute of Technology
  • Country:
    Israel

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