Study of arrayed side branch silencer for ventilation door (Theoretical analysis and measurement of transmission loss)

Sakamoto, Shuichi; Tatsuza, Seiya; Ishida, Munehiro; Nakano, Arata; Nagai, Kuniaki; Katou, Toshio

doi:10.1299/jamdsm.2015jamdsm0028

Cited by 4 publications

(1 citation statement)

References 16 publications

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“…In this case, the natural frequency and damping ratio of a damped dynamic vibration absorber must be optimally tuned. Acoustic Keisuke YAMADA*, Tatsuya SHIMIZU*, Hideo UTSUNO*, Junichi KURATA* and Yoshihiro MURAKAMI* silencers such as side-branches and Helmholtz resonators are types of dynamic vibration absorbers (Chanaud, 1994;Ichiyanagi and Nishiumu, 2008;Ingard, 1953;Sakamoto et al, 2015;Ishihara, 2010, 2011); however, damped acoustic silencers have not been studied sufficiently thus far. Therefore, the first purpose of this study is to derive the optimum tuning conditions for damped acoustic silencers.…”

Section: Introductionmentioning

confidence: 99%

Optimum tuning of damped side-branch silencer using equivalent discrete model and considering open-end correction

Yamada

Shimizu

Utsuno

et al. 2021

Mechanical Engineering Journal

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This paper describes the optimum tuning of damped side-branch silencers. As is well known, a side-branch silencer is a type of vibration absorber; however, damped side-branch silencers have not yet been sufficiently studied. In this study, to derive the optimum tuning conditions of a side-branch silencer, modal analysis was applied to wave equations of a host acoustic field and a side-branch silencer. Using the equations of motion with the modal coordinate system, an equivalent discrete model of the coupled vibration system between the host acoustic field and side-branch silencer was obtained. The degrees of freedom of the equivalent discrete model were reduced to two by ignoring the non-related acoustic modes, and the two fixed point method was applied to the two degree of freedom vibration system to derive the optimum natural frequency ratio and optimum loss factor of the side-branch silencer. In addition, open-end correction of the side-branch silencer was formulated considering the effect of residual acoustic modes of the host acoustic field. A theoretical analysis with respect to the optimum tuning conditions and open-end correction was validated through simulations and experiments.

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Section: Introductionmentioning

confidence: 99%

Optimum tuning of damped side-branch silencer using equivalent discrete model and considering open-end correction

Yamada

Shimizu

Utsuno

et al. 2021

Mechanical Engineering Journal

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Sound reduction of side-branch resonators: An energy-based theoretical perspective

Li,

Chang Gea

2024

AIP Advances

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For over a century, side-branch resonators have served as effective acoustic filters, yet the explanation for their sound reduction capability has varied. This paper introduces a novel theory applicable to all types of side-branch resonators from an energy perspective and explains sound reduction as a consequence of acoustic energy redistribution. Our theory posits that a standing wave inside the resonator induces air vibration at the opening, which then acts as a secondary sound source, emitting acoustic energy predominantly in the form of kinetic energy. Due to the formation process of the standing wave, the sound wave generated by the resonator undergoes a phase shift relative to the original sound wave in the main pipe. Consequently, this generated sound wave, while matching the amplitude, possesses an opposite phase compared to the original noise wave within the main pipe. This antiphase relationship results in the cancellation of sound waves when they interact post-resonator in the main pipe. Our theory, grounded in an energy perspective, is derived from the principles of standing wave vibration and energy conservation.

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A silencer incorporated within the thickness of the edge of the door for increasing sound transmission loss

Sakamoto

Koseki

Chinda

et al. 2018

The Journal of the Acoustical Society of America

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The present study focuses on a silencer built within the thick portion of a door edge and reports on the results of evaluating silencers by determining sound transmission loss via theoretical analysis and experiments on three types of silencers. The theoretical analysis involved determining the calculated values of sound transmission loss obtained using the transfer matrix method. The change in cross-sectional shape was analyzed by elemental division of the transfer matrix. Using the above, simulations were performed with respect to the optimum shape of the silencer. These theoretical analyses were then compared with the measurement results. Furthermore, the study includes the results of an experiment that attempted to restrain the dip in sound transmission loss by adding a non-woven fabric to the opening of the silencer. In a side branch silencer with an increasing shape wherein the longitudinal cross-section is a linear or an exponential function, the peak of the transmission loss was shifted to the lower frequency side when compared with that in the case of a rectangular side branch silencer. Furthermore, in comparisons between the two, the sound attenuation peak frequency was lower in the case of the exponential shape. The resonance of the side branch was suppressed by adding a non-woven fabric to the opening of the side branch silencer. As a result, the peak and dip of sound attenuation were alleviated, and the sound attenuation characteristics could be adjusted.

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Study of arrayed side branch silencer for ventilation door (Theoretical analysis and measurement of transmission loss)

Cited by 4 publications

References 16 publications

Optimum tuning of damped side-branch silencer using equivalent discrete model and considering open-end correction

Optimum tuning of damped side-branch silencer using equivalent discrete model and considering open-end correction

Sound reduction of side-branch resonators: An energy-based theoretical perspective

A silencer incorporated within the thickness of the edge of the door for increasing sound transmission loss

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