A study on the Acoustic Mode and Cavity-Tone in a Perforated Tube Muffler

다공형 소음기의 음향 모우드와 공동음에 관한 연구

The acoustic mode of a perforated tube muffler was investigated both theoretically and experimentally to explain the cavity-tones induced by through-flow. The cutoff frequencies for the axisymmetric modes were obtained and confirmed experimentally. It was found that the cutoff frequencies are decreased significantly by the perforated tube. The onset frequencies of the cavity-tones were compared with the cutoff frequencies of the acoustic mode and it was found that the cavity-tones are induced by the radial acoustic modes and their frequency stages are coincident with the discrete cutoff frequencies.