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Scattering Behavior of High Frequency Acoustic Waves Due to Blockage in Pressurized Water-Filled Pipe

Author(s): Moez Louati, Mohamed S. Ghidaoui

Linked Author(s): Moez LOUATI

Keywords: Transient waves, pipe system, wave-blockage interaction, wave dispersion, wave scattering

Abstract: Recently, high frequency acoustic waves (HFW) have become of interest to increase the resolution for transient-based defect detection methods. For this purpose, one has to know how these HFW, which are dispersive waves, interact with defects. This paper considers the case of a blockage and studies numerically the scattering behaviour of HFW due to a single blockage in pipe system with non-reflective boundaries. For simplicity, axisymmetry is assumed and only signals that excite up to two radial modes are considered. Although the paper is mainly describing what was obtained from the numerical simulation, it is important to note that the objective is to understand the features of the scattering behaviour of HFW from a blockage that could be used for blockage detection. The results show that wave scattering increases the dispersion and distortion of HFW. This is because the energy of the incoming waves is distributed into multiple transmitted and reflected modes. Moreover, it is shown that the plane wave mode is highly affected by the severity of area reduction. The more severe the reduction is, the more the energy of a plane wave is reflected. However, radial modes have little interaction with the blockage and transmit most of their energy through both severe and shallow blockage cases


Year: 2017

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