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STUDY ON THEREDUCTION OF AERODYNAMIC NOISE BY VORTEX CONTROL

涡控制降低气动噪声的研究

基本信息

批准号：
15560151
负责人：
TOYODA Kuniaki
金额：
$ 2.05万
依托单位：
HOKKAIDO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560151/
关键词：
AERODYNAMIC NOISE JET VORTEX CONTROL SEPARATED FLOW SOUND SOURCE

项目摘要

The objective of the present study is to obtain the basic materials for the vortex control techniques to reduce the aerodynamic noise. The results are summarized as follows.(1)The effect of tabs (vortex generators) on jet noise was investigated by flow visualization experiments and phase-average measurements. The results reveal the interaction mechanism of vortex rings and streamwise vortices to lead to the suppression of sound generation. In particular, it is very important in engineering applications to make clear the cut-and-reconnection mechanism of the streamwise vortices wound around the vortex rings and to confirm the suppression of vortex pairing.(2)The effect of pile-fabrics on reducing aerodynamic noise was investigated by measuring the noise from a square cylinder in uniform flow. The results show that the pile-fabrics on the cylinder are effective to suppress the vortex evolution and pairing of separated flow and to reduce the noise related to the vortex motions.(3)The sound source of the separated mixing layer from a fence was discussed by the measurements of velocity and pressure fluctuations. The results reveal that the sound source intensity is high in the regions of vortex evolution and pairing. The propagated sound detected simultaneously with flow visualization also suggests that the sound source is closely related to the vortex motions.(4)Based on the results of the present study and the related studies, the vortex control techniques to reduce aerodynamic noise are proposed, and the future works are suggested.

本研究的目的是为涡流控制技术降低气动噪声提供基础材料。主要研究结果如下：(1)通过流动显示实验和相平均测量，研究了翼片(涡流发生器)对射流噪声的影响。结果揭示了涡环与流向涡相互作用导致发声抑制的机理。特别是在工程应用中，弄清涡环周围流向涡的切割和重联机理，并证实涡对的抑制作用。(2)通过测量均匀流中方柱的噪声，研究了绒面织物对气动噪声的抑制作用。结果表明，圆柱体上的绒布能有效地抑制分离流的旋涡演化和配对，降低与旋涡运动相关的噪声。(3)通过速度和压力脉动的测量，讨论了栅栏分离混合层的声源。结果表明，在涡旋演化和配对区，声源强度较高。在流动显示的同时探测到的传播声也表明声源与涡流运动密切相关。(4)基于本文的研究结果和相关研究，提出了降低气动噪声的涡流控制技术，并对下一步的工作进行了展望。