Development of a New Method for Alleviation of Impulsive Aerodynamic - Noise by Means of Water - Sheet

开发一种利用水板减轻脉冲气动噪声的新方法

• 批准号: 01850044
• 负责人: MATSUO Kazuyasu
• 金额: $ 4.8万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1991
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-01850044/
• 关键词: Impulsive noise; Aerodynamic noise; Attenuation of compression wave; Water - sheet; Wave motion

1. When a compression wave propagates along a tube and reaches its open end, an impulsive wave is emitted outward from its exit toward the surrounding area, which causes an impulsive noise. In the present study, the attenuation and change of waveform of a propagating compression wave, the generation process of the impulsive wave at the exit, and some practical means for alleviation of the impulsive noise have been investigated.2. The strength of a compression wave decreases exponentially with the distance. Numerical calculation has been carried out taking unsteady friction into account instead of steady one. Unsteady friction causes more distortion of the compression waveform and the calculated waveform is in better agreement with the measured one.3. The magnitude of an impulsive wave generated at the open end is nearly proportional to the maximum rate of pressure change of the compression wave coming to the exit. The experimental results of the magnitude at the exit agree well with the results by aeroacoustic analysis where an open end correction is considered.4. A method for alleviation of the magnitude of impulsive noises by means of water-sheet has been developed, and it is confirmed that the present method is quite useful, although the directivity of the controlled noise field is rather strong. Some other methods for reducing the magnitude of impulsive noises such as an application of active noise control system have been developed in the present investigation. The active control system may be the most useful method in these ones.

1.当压缩波沿着管道传播并到达其开口端时，从其出口向周围区域向外发射脉冲波，这引起脉冲噪声。本文研究了压缩波传播过程中波形的衰减和变化，出口处脉冲波的产生过程，以及抑制脉冲噪声的一些实用方法.压缩波的强度随距离呈指数下降。数值计算中考虑了非定常摩擦力而不是定常摩擦力。非定常摩擦使压缩波形畸变较大，计算波形与实测波形吻合较好.在开口端处产生的冲击波的幅度几乎与到达出口的压缩波的最大压力变化率成比例。出口处的实验结果与考虑开口修正的气动声学分析结果吻合较好.本文提出了一种利用水膜抑制脉冲噪声的方法，并证实了这种方法是十分有用的，尽管受控噪声场的方向性很强。在本研究中还提出了其他一些降低脉冲噪声幅度的方法，如应用有源噪声控制系统。主动控制系统是解决这类问题最有效的方法。

项目成果

Toshiaki Setoguchi: "A study of negative impulsive wave generator for reducing impulsive noise" Preprint of Japan Society of Mechanical Engineering. (1992)

Toshiaki Setoguchi：“用于减少脉冲噪声的负脉冲波发生器的研究”日本机械工程学会预印本。

Toshiaki Setoguchi: "Discharge of a weak shock wave from an open end of a tube" Proceedings of the 1989 National Symposium on Shock Wave Phenomena. 31-40 (1990)

Toshiaki Setoguchi：“从管的开口端释放弱冲击波”1989 年全国冲击波现象研讨会论文集。

青木 俊之: "圧縮波の開口端からの放出によるパルス音" 日本機械学会講演論文集. 914. 131-133 (1991)

Toshiyuki Aoki：“开放端压缩波发射产生的脉冲声”日本机械工程师学会会议记录 914. 131-133 (1991)。

Toshiaki Setoguchi: "Reduction of impulsive noise induced by a weak shock wave discharged from an open end of a tube" Preprint of Japan Society of Mechanical Engineers. 914. 134-136 (1991)

Toshiaki Setoguchi：“减少从管的开口端释放的弱冲击波引起的脉冲噪声”日本机械工程师学会预印本。

松尾 一泰: "Discharge of a weak shock wave from an open end of a tube" Proceedings of the 1989 National Symposium on Shock Wave Phenomena. 31-40 (1990)

Kazuyasu Matsuo：“从管的开口端释放弱冲击波”1989 年全国冲击波现象研讨会论文集 31-40 (1990)。