空洞形消音器で発生する気流騒音 : 第2報, 騒音特性におよぼす空洞内共鳴の影響

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This paper describes the relationship between the flow noise generated secondarily in cylindrical expansion chambers and chamber resonance. In a sound pressure spectrum measured inside each chamber tested, the resonance components appear at the frequency determined by the chamber dimensions and the mode of vibration in the cylindrical sound field produced in the chamber. The resonance in connection with the radial vibration mode is intensified when its frequency approaches that of the dominant component of flow-generated noise caused by the impact of the jet to the exit of the chamber of which the length is less than four times of pipe diameter. In this case, the sound pressure level of flow noise emitted from the tail-pipe end excels by a very large amount at the frequency close to the resonance frequency, so that its overall value increases. The ranges of chamber size and mean flow velocity, in which the amplified chamber resonance occurs, may be presumed by using Fig. 11 arranged with a Strouhal number and the formula for resonance frequency on the circular sound field.
社団法人日本機械学会の論文
1992-02-25