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Determination of Plane-wave Reflection Coefficient in Underwater Acoustic Pulse Tube Using Two-dimensional Fourier Filtering

이차원 푸리에 필터링을 이용한 수중음향 펄스 튜브에서의 평면파 반사계수 결정

Kim, Wan-Gu;Kang, Hwi Suk;Yoon, Suk Wang
김완구;강휘석;윤석왕

  • Received : 2015.10.08
  • Accepted : 2015.11.16
  • Published : 2015.11.30

Abstract

Complex acoustic signals can be formed in a water-filled acoustic pulse tube under some exciting conditions. It makes difficult to measure plane-wave reflection coefficient with the pulse tube for low frequency bands. In this study, using COMSOL Multiphysics we show that the tube wall excitation generates complex acoustic field of nonplanar mode as well as planar one. From such field incident or reflected planar mode can be decomposed respectively with a modal decomposition method, two-dimensional Fourier filtering. It makes possible to more accurately determine the plane-wave reflection coefficient of acoustic specimen with time gating.

Keywords

Pulse tube;Mode decomposition;Two-dimensional Fourier filtering;Plane-wave reflection coefficient

References

  1. T. R. Howarth, V. K. Varadan, X. Bao, and V. V. Varadan, "Piezocomposite coating for active underwater sound reduction," J. Acoust. Soc. Am. 91, 823-831 (1992). https://doi.org/10.1121/1.402542
  2. B. Philip, J. K. Abraham, V. K. Varadan, V. Natarajan, and V. G. Jayakumari, "Passive underwater acoustic damping materials with Rho-C rubber-carbon fiber and molecular sieves," Smart Mater. Struct. 13, N99-N104 (2004). https://doi.org/10.1088/0964-1726/13/6/N01
  3. P. S. Wilson, R. A. Roy, and W. M. Carey, "An improved water-filled impedance tube," J. Acoust. Soc. Am. 113, 3245-3252 (2003). https://doi.org/10.1121/1.1572140
  4. J. C. Wilbur, An impedance tube for the in-situ classification of bubbly liquids, (Master Thesis, Boston University, 2004).
  5. L. Martinez, N. Wilkie-Chancellier, B. Sarens, and C. Glorieux, "2D Finite Impulse Response filters for surface wave identification," IEEE International Ultrasonics Symposium Proceedings, 1598-1601 (2009).
  6. D. Alleyne and P. Cawley, "The Interaction of Lamb Waves with Defects," IEEE Trans. UFFC 39, 381-397 (1992).
  7. L. D. Lafleur and F. D. Shields, "Low-frequency propagation modes in a liquid-filled elastic tube waveguide," J. Acoust. Soc. Am. 97, 1435-1445 (1995). https://doi.org/10.1121/1.412981

Acknowledgement

Supported by : 국방과학연구소