National Aerospace Laboratory
宇宙航空研究開発機構
宇宙航空研究開発機構
著者所属（英）
National Aerospace Laboratory
Japan Aerospace Exploration Agency
Japan Aerospace Exploration Agency
出版者
宇宙航空研究開発機構
出版者（英）
Japan Aerospace Exploration Agency (JAXA)
雑誌名
宇宙航空研究開発機構特別資料: 境界層遷移の解明と制御研究会講演論文集 第40回
雑誌名(英)
JAXA Special Publication: Proceedings of the 40th JAXA Workshop on Investigation and Control of Boundary-Layer Transition
巻
JAXA-SP-07-026E
ページ
25 - 26
発行年
2008-02-29
抄録（英）
The generation of tonal noise by airfoils has been a continuing problem of which the overall mechanism still remains yet to be uncovered. Results of an experimental investigation on tonal noise generation are presented. Quantitative measurements were obtained by use of hotwire and microphone. Furthermore, a flow visualization of the phenomenon was carried out by use of a smoke wire technique. Based on these experiments, a detailed description of the flow close to the trailing edge is obtained. The sound generation process takes place on the pressure side in the near-trailing edge region, where a thin layer of separated flow exists, which is essential to the mechanism. A Kelvin-Helmholtz instability appears to be the cause of the vortex generation. The interaction of shedding eddies with the trailing edge, resulting in the emission of pressure waves, represents the noise source. Events on the suction side are found to be of no significant influence to the sound generation mechanism. The role of TS (Tollmien Schlichting) waves in the sound generation process is re-evaluated and a novel self-excited feedback loop is proposed to explain the occurrence of tonal noise generation.
An investigation on airfoil tonal noise generation
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