著者

劉 本柱 三上 真人 小嶋 直哉

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集B編 (ISSN:03875016)

巻号頁・発行日

vol.62, no.600, pp.3220-3226, 1996

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The flow induced noise from an expansion cavity-type muffler increases abruptly for some sizes of mufflers and flow velocities. This phenomenon is strongly related to the resonance of the tail pipe and the cavity of the muffler ; therefore, it is called the predominance of resonance″When the cavity length is increased, the measured resonance frequency shows periodic jumps. The cause of the predominance of resonance is assumed to be the generation of vortex rings with a particular frequency in the cavity. The generation of vortex rings is verified by analyzing fluctuating velocities in the cavity when the predominance of resonance occurs. The phenomenon is induced not only by the tail pipe resonance, but also by the cavity resonance. It is suggested that there exists the feedback phenomenon from the sound to the flow and it is strongly related to the sound pressure level in the cavity.

著者

劉 本柱 三上 真人 小嶋 直哉

雑誌

日本騒音制御工学会技術発表会講演論文集

巻号頁・発行日

vol.1995, pp.205-208, 1995-09

参考文献数

4

著者

劉 本柱 三上 真人 小嶋 直哉

出版者

一般社団法人日本機械学会

雑誌

日本機械学会論文集. B編 (ISSN:03875016)

巻号頁・発行日

vol.62, no.600, pp.3220-3226, 1996-08-25

参考文献数

11

被引用文献数

2

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The flow induced noise from an expansion cavity-type muffler increases abruptly for some sizes of mufflers and flow velocities. This phenomenon is strongly related to the resonance of the tail pipe and the cavity of the muffler ; therefore, it is called the predominance of resonance゛When the cavity length is increased, the measured resonance frequency shows periodic jumps. The cause of the predominance of resonance is assumed to be the generation of vortex rings with a particular frequency in the cavity. The generation of vortex rings is verified by analyzing fluctuating velocities in the cavity when the predominance of resonance occurs. The phenomenon is induced not only by the tail pipe resonance, but also by the cavity resonance. It is suggested that there exists the feedback phenomenon from the sound to the flow and it is strongly related to the sound pressure level in the cavity.

著者

劉 本柱 岡 智弘 三上 真人 小嶋 直哉

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. B編 (ISSN:03875016)

巻号頁・発行日

vol.63, no.611, pp.2500-2506, 1997-07-25

被引用文献数

1

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Predominant resonance can occur in flow-induced noise from an expansion-cavity-type muffler for particular combinations of muffler configuration and flow velocity. This phenomenon is caused by self-excited oscillation based on the feedback response from acoustic resonances of the muffler to shear flow. Usually, the sound pressure level is much higher when predominance of tail pipe resonance rather than cavity resonance occurs. The predominance of tail pipe resonance is shown to be strongly influenced by both the frequency characteristics of acoustic amplification of the tail pipe and the frequency of velocity fluctuation with a certain phase criterion. The predominance phenomena can be generalized using a new dimensionless independent variable, (L/l')(1/M), where L, l' and M are cavity length, acoustically equivalent tail pipe length and Mach number in the tail pipe, respectively.