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NACA翼形における後流渦形成と離散周波数騒音の関係に関する実験的研究


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Title: NACA翼形における後流渦形成と離散周波数騒音の関係に関する実験的研究
Other Titles: Relationship between Wake Vortex Formation and Discrete Frequency Noise in NACA Blades
Authors: 林, 秀千人 / 児玉, 好雄 / 深野, 徹 / 池田, 昌浩
Authors (alternative): Hayashi, Hidechito / Kodama, Yoshio / Fukano, Tohru / Ikeda, Masahiro
Issue Date: 25-Jun-1995
Publisher: 社団法人日本機械学会 / The Japan Society of Mechanical Engineers
Citation: 日本機械学會論文集. B編, 61(586), pp.2109-2114; 1995
Abstract: Effects of blade thickness on discrete frequency noise (DFN) have been investigated using symmetrical NACA blades of three different thicknesses. It was clarified that the mechanism of DFN generation was different depending on the thickness of the blade. In the case of a thin blade, NACA 0008, the air flow was separated upstream of the trailing edge on the suction side of the blade, but was attached to the trailing edge of the blade on the pressure side. Therefore the frequency and the sound pressure level of DFN were varied with the variation of the attack angle. On the other hand, in the case of a thick blade, NACA 0015 or NACA 0018, the flow was separated upstream of the trailing edge on the pressure side while it was attached to the trailing edge on the suction side. The frequency and sound pressure level of DFN did not vary with the variation of the attack angle in these cases. The location of the rolling up of Karman vortices was very important in the generation of DFN. When rolling up of the Karman vortex took place far from the trailing edge of the blade, the Karman vortices did not have a strong effect on the flow around the blade. However, when Karman vortices rolled up in the vicinity of the blade, the interaction of the Karman vortices with the blade was strong, causing DFN generation.
Keywords: Vortex / Aerodynamic Acoustics / Wake / Separation / Unsteady Flow / Blade Thickness
URI: http://hdl.handle.net/10069/22749
ISSN: 03875016
Relational Links: http://ci.nii.ac.jp/naid/110002394435/
Rights: 社団法人日本機械学会 / 本文データは学協会の許諾に基づきCiNiiから複製したものである
Type: Journal Article
Text Version: publisher
Appears in Collections:Articles in academic journal

Citable URI : http://hdl.handle.net/10069/22749

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