Absorption and transmission of boundary layer noise through flexible multi-layer micro-perforated structures

Bravo, Teresa; Maury, Cédric; Pinhède, Cédric

doi:10.1016/j.jsv.2017.02.018

Cited by 34 publications

(7 citation statements)

References 40 publications

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“…It can be seen from the open public literature that there has been a considerable number of noise reduction methods available for the piping systems, e.g., (i) arrangement of elastic joints, corrugated pipe/bellows, or other components to the piping systems [5][6][7][8]; (ii) installation of a muffler elbow and micro-perforated plates [9,10]; (iii) avoidance of short-radius elbow, sharp bends, and branch pipes in pipeline [11]; (iv) laying damping materials [9]; (v) active control technologies [12][13][14][15]; and installation of pipe mufflers [16][17][18][19], etc. Particularly, installation of a pipe muffler is the most widely used means among these methods.…”

Section: Introductionmentioning

confidence: 99%

Transmission of Low-Frequency Acoustic Waves in Seawater Piping Systems with Periodical and Adjustable Helmholtz Resonator

Liu

Yang

2017

JMSE

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Abstract:The characteristics of acoustic wave transmitting in a metamaterial-type seawater piping system are studied. The metamaterial pipe, which consists of a uniform pipe with air-water chamber Helmholtz resonators (HRs) mounted periodically along its axial direction, could generate a wide band gap in the low-frequency range, rendering the propagation of low-frequency acoustic waves in the piping system dampened spatially. Increasing the air volume in the Helmholtz chamber would result in a sharply decrease in the central frequency of the resonant gap and an extension in the bandwidth in the beginning, yet very slowly as the air volume is further augmented. Acoustic waves will experience a small amount of energy loss if the acoustic-structure interaction effect is considered. Also, the structure-borne sound will be induced because of the interaction effects. High pressure loadings on the system may bring in a shrink in the band gap; nevertheless, the features of broad band gaps of the system is still be maintained.

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Section: Introductionmentioning

confidence: 99%

Transmission of Low-Frequency Acoustic Waves in Seawater Piping Systems with Periodical and Adjustable Helmholtz Resonator

Liu

Yang

2017

JMSE

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“…The energy loss increases with the frequency increasing. 15 When the tube shrink to capillary, the energy loss no longer increases with the frequency increasing. The energy loss has a positive relationship with the hole radius, and the porosity.…”

Section: Discussionmentioning

confidence: 99%

Numerical simulations and experiments on thermal viscous power dissipation of perforated plates

Gang

Liu

et al. 2018

AIP Advances

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The micro-perforated plates (MPPs) are widely used in sound absorption structures. As perforations become smaller, the energy loss caused by viscous dissipation and thermal radiation of the medium should be considered on calculation and design of the MPPs. In this paper, the energy loss of thin tube, micro tube and capillary tube are analyzed by using the finite element method (FEM). The acoustic finite element models of MPPs are created, and the power dissipation, impedance, resonant frequency, absorption coefficient and correction length of perforated plates are analyzed. The impedance experiments are carried to test the numerical results. This paper approves that the energy loss caused by thermal and viscous should be considered on MPPs, which is determined by air viscous, and affected by the diameter of perforations, porosity and frequency. The resonant frequency is affected by viscous. The theoretical formula of Helmholtz resonator cause great error for micro-perforated plates usage, and it should be calculated by numerical simulation in the field of MPPs design and application.

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“…Panels of Foam: Foam panels are useful for absorbing mid-to high-frequency sounds since they are lightweight and adaptable (Bravo et al, 2017).…”

Section: Sound Absorbing Materialsmentioning

confidence: 99%

Enhancing Sound Transmission Loss in Hybrid Mufflers with Change in Pipe Perforation and Using Absorptive Material

Jatola,

Gupta

2023

IJERR

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It is well known that baffled exhaust mufflers enhance sound transmission loss while lowering noise emissions. Sound transmission loss can be further reduced by adding sound-absorbing material inside the silencer. It has been demonstrated that carefully placed baffles in exhaust silencer systems improve acoustic performance by successfully lowering noise emissions. Sound waves are redirected and disrupted by baffles, which lessens the transmission of undesired noise and creates a more controlled and tranquil acoustic environment. The incorporation of sound-absorbing materials into mufflers is a significant development in noise control technology. Specialized materials are added to the muffler to improve sound wave absorption and drastically reduce noise emissions. This novel method not only enhances acoustic performance but also improves a variety of applications—from industrial gear to automobile exhaust systems—making them quieter and more enjoyable to use. A silencer was constructed for this research project using the finite volume method. The design's efficacy was demonstrated through experimental validation. The research project then used the finite volume technique to produce a silencer with the same dimensions. It then adjusted the design based on different flow percentages, adding a baffle and making pipe perforations, until the optimal silencer design was found. Additionally, this approach provides an optimal design and indicates which sound-absorbing material has the largest sound transmission loss.

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Absorption and transmission of boundary layer noise through flexible multi-layer micro-perforated structures

Cited by 34 publications

References 40 publications

Transmission of Low-Frequency Acoustic Waves in Seawater Piping Systems with Periodical and Adjustable Helmholtz Resonator

Transmission of Low-Frequency Acoustic Waves in Seawater Piping Systems with Periodical and Adjustable Helmholtz Resonator

Numerical simulations and experiments on thermal viscous power dissipation of perforated plates

Enhancing Sound Transmission Loss in Hybrid Mufflers with Change in Pipe Perforation and Using Absorptive Material

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