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

Wan-Gu Kim; Hwi Suk Kang; Suk Wang Yoon

doi:10.7776/ASK.2015.34.6.493

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2015 Vol.34, Issue 6 Preview Page

Determination of Plane-wave Reflection Coefficient in Underwater Acoustic Pulse Tube Using Two-dimensional Fourier Filtering 이차원 푸리에 필터링을 이용한수중음향 펄스 튜브에서의 평면파 반사계수 결정

30 November 2015. pp. 493-498

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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

물로 채워진 음향 펄스 튜브 내에는 가진 조건들에 따라 복잡한 형태의 음향 신호들이 형성될 수 있다. 이는 펄스 튜브를 이용해 저주파수 대역에서 평면파 반사계수를 측정하는 것을 어렵게 한다. 본 연구에서는 COMSOL Multiphysics를 이용하여 튜브 벽이 가진되는 경우 펄스 튜브 내에 평면파 뿐 아니라 비평면파 모우드의 복잡한 음장이 발생됨을 보였다. 모우드 분리 방법인 이차원 푸리에 필터링으로 입사 또는 반사하는 평면파 모우드만을 각각 분리할 수 있었다. 이에 시간 게이팅을 적용하므로 음향 시편의 평면파 반사계수를 보다 정확하게 결정할 수 있게 하였다.

키워드

펄스 튜브

모우드 분리

이차원 푸리에 필터링

평면파 반사계수

References

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Information

Publisher :The Acoustical Society of Korea
Publisher(Ko) :한국음향학회
Journal Title :The Journal of the Acoustical Society of Korea
Journal Title(Ko) :한국음향학회지
Volume : 34
No :6
Pages :493-498
Received Date : 2015-10-08
Revised Date : 2015-11-09
Accepted Date : 2015-11-16
DOI :https://doi.org/10.7776/ASK.2015.34.6.493

The Journal of the Acoustical Society of KoreaISSN:1225-4428(Print) 2287-3775(Online)한국음향학회

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