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Theoretical analysis of sound reduction property in one-dimensional random duct and its application to noise control

一维随机风道消声特性理论分析及其在噪声控制中的应用

基本信息

批准号：
17560403
负责人：
NAKASAKO Noboru
金额：
$ 1.34万
依托单位：
Kinki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560403/
关键词：
one-dimensional sound field random media random loadings distributed parameter circuit sound reduction property localization computer simulation noise control 分布乗数回路

项目摘要

It is known that a wave cannot propagate long distance in random media and is confined in a small region when the field is excited. In physics it is called the "localization", the phenomenon which is closely related to the cut-off (non-propagating) state of waves in a certain broad frequency band. It is expected that this property can be utilized as a muffler to reduce the sound noise because the sound propagating in random media or random loadings would exhibit strong exponential decay along distance. On the other hand, a one-dimensional acoustic duct can be expressed by a transmission line model commonly used in the study of microwave waveguide. In this research, I focus on the sound decaying property of one-dimensional duct (random duct) and demonstrate the validity of the proposed theory through a computer simulation. The results I obtained in 2005 and 2006 are listed below.[2005 year] : As the first step of research, I expressed the sound field in duct by a transmission line model, on which I theoretically analyzed the ordinary one-dimensional duct and carried out computer simulation. Based on the circuit representation, I theoretically proposed the sound reduction property in a case when there exist random media in duct. To confirm the validity of the analysis, I performed the computer simulation and showed the existence of the strong exponential decay. These results have been published in a scientific journal and presented in domestic conference.[2006 year] : Following to the fundamental consideration on the sound reduction problem with randomness in 2005, I theoretically proposed the sound reduction property in a case when there exist random loadings in duct and the extensive simulation makes it clear that the proposed method also enables us to cause the strong exponential decay. These results have been presented in international conferences.

众所周知，波不能在随机介质中长距离传播，并且当场被激发时波被限制在一个小区域内。物理学上称之为“局域化”，这种现象与波在某一宽频带内的截止（非传播）状态密切相关。预计该特性可用作消声器以减少声音噪声，因为在随机介质或随机负载中传播的声音将沿距离表现出强烈的指数衰减。另一方面，一维声波导可以用微波波导研究中常用的传输线模型来表示。在这项研究中，我重点研究一维管道（随机管道）的声音衰减特性，并通过计算机模拟证明了所提出理论的有效性。我在2005年和2006年取得的成果如下： [2005年]：作为研究的第一步，我用传输线模型表达了管道内的声场，在此基础上对普通一维管道进行了理论分析并进行了计算机模拟。基于电路表示，我从理论上提出了管道中存在随机介质的情况下的降噪特性。为了确认分析的有效性，我进行了计算机模拟并证明了强指数衰减的存在。这些成果已发表在科学期刊上，并在国内会议上发表。 [2006年]：继2005年对随机性降噪问题的基本思考之后，我从理论上提出了管道中存在随机载荷的情况下的降噪特性，并且广泛的模拟表明，所提出的方法也使我们能够引起强指数衰减。这些成果已在国际会议上发表。