Noise attenuation performance improvement by adding Helmholtz resonators on the periodic ducted Helmholtz resonator system

Cai, Chenzhi; Mak, Cheuk Ming; Wang, Xu

doi:10.1016/j.apacoust.2017.02.006

Cited by 36 publications

(20 citation statements)

References 19 publications

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“…These resonators are often Helmholtz resonators (HRs) or quarter-wavelength resonators (QWRs), but each independent resonator operates efficiently only in a relatively narrow frequency range. Detuned HRs are thus arranged in series, parallel, or both [2][3][4][5][6] to broaden the silencer efficiency frequency range. These detuned HR arrays can then be optimized.…”

Section: Introductionmentioning

confidence: 99%

Optimized reactive silencers composed of closely-spaced elongated side-branch resonators

Červenka

Bednařı́k

Groby

2019

The Journal of the Acoustical Society of America

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This paper reports a theoretical study of the sound propagation in a rectangular waveguide loaded by closely-spaced elongated side-branch resonators forming a simple low-frequency broadband reactive silencer. Semi-analytical calculations account for the evanescent modes both in the main waveguide and side-branch resonators and for the viscothermal losses in the silencer elements. Reasonable accuracy is maintained in the evaluation of transmission, reflection, and absorption coefficients, while the calculation time is reduced by a few hundred times in comparison with the finite element method. Therefore, the proposed method is particularly suitable for optimization procedure. The lengths of the individual equally spaced side-branch resonators are optimized by a heuristic evolutionary algorithm that maximizes the minimum transmission loss (TL) over a pre-defined frequency range. Numerical results indicate that the minimum TL of the optimized silencers is reduced due to the destructive effect of the evanescent coupling from the resonators of the nearest side-branches. In the opposite, the TL increases linearly with the number of the side-branch resonators. V

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Section: Introductionmentioning

confidence: 99%

Optimized reactive silencers composed of closely-spaced elongated side-branch resonators

Červenka

Bednařı́k

Groby

2019

The Journal of the Acoustical Society of America

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“…In theoretical works, 3,4 the authors studied the transmission properties of a duct with periodically mounted identical HRs; interaction of several pieces of these arrays was also studied. 5 Transmission properties of periodic ducted HRs with added parallel HRs were theoretically and numerically studied in Cai et al, 6 hybrid noise control using dual periodic HRs was also presented. 7 Coulon et al 8 studied the role of the distances between differently tuned HRs in an array, they used an optimization approach to improve the overall wide-band transmission properties.…”

Section: Introductionmentioning

confidence: 99%

“…It is also assumed that the waveguide downstream the silencer is infinite (or anechoic), so that there is no wave impinging from the right side. Within this work, as it has been adopted in the previous works, [3][4][5][6][7][8][9][10][11] the fluid is considered non-dissipative (all forms of acoustic energy dissipation are neglected), and stationary. Even if in almost all practical applications the fluid would be moving, the assumption of stationary fluid does not represent too much simplification, as Tang and Li 12 have reported that slow in-duct airflow does not affect the transmission loss of single or double sidebranch arrangements very much.…”

Section: Introductionmentioning

confidence: 99%

Optimized reactive silencers with narrow side-branch tubes

Červenka

Bednařı́k

2018

The Journal of the Acoustical Society of America

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This paper presents a theoretical study of the sound propagation in a waveguide loaded by an array of flush-mounted narrow side-branch tubes, forming a simple low-frequency reactive silencer. The individual tube-lengths and the distances between the adjacent tubes are optimized in order to maximize the minimum transmission loss over a given frequency range. The transmission properties of the silencer are calculated using the transfer matrix method, heuristic evolutionary approach is employed for the determination of the optimal parameters. The numerical results are validated against the finite element method simulation. A comprehensive parametric study is performed to demonstrate the optimized silencer performance as a function of the number of side-branch tubes, and the frequency range. It is shown that for the given frequency range, the minimum transmission loss of the optimized silencer increases linearly with the number of the side-branch tubes.

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“…Propagation of waves inside periodic structures has yielded increasing attention in the last years [25][26][27][28][29][30]. The interest of the SC has concentrated on increasing their acoustical focalization [31] and attenuation properties in the last years [22,32].…”

Section: Introductionmentioning

confidence: 99%

Designing, constructing and testing of a new generation of sound barriers

Negahdari

Javadpour

Moattar

2019

J Environ Health Sci Engineer

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Purpose Nowadays, noise pollution is considered a major environmental problem which has affected the health and comfort of millions of people around the world. Solving the mentioned problems need to design a new generation of acoustic barriers. Acoustics experts believe that stopping and absorbing the low-frequency sound is difficult. The aims of this study were to remove the harmful frequency in industries and cities. This study concentrates on the reduction of the noise level and increasing the mass law and resonance at low frequencies. Methods Sound measurement and frequency analysis did to fix the harmful frequency in the Shiraz city and in the Shiraz Gas Power Plant. COMSOL 5.3a software used for simulation. Suitable material chose for the manufacture of the sound barrier through the Cambridge engineering selection software 2013. The meta-material sound barrier made and tested in the acoustic room and in the free space. Results analyzed and optimized by Design of Experiment (DOE) and Response Surface Methodology (RSM) software. Mini Tab. 18.1 software used for Statistical Calculations. New sound barriers manufactured with adding new strategies to previous studies to improve the performance of meta-materials like beautification inspired from the flowers of nature and increasing of resonance in internal pipes. Results Three mechanisms used in this scatterer model which included, resonance phenomenon, Band Gap (BG) without absorption mechanism and inner-fractal-like structure. Our technique showed an advantage to reduce at frequencies below 100 Hz without adsorbent usage. The results showed that reduced noise exposures about 17.8 dB at frequency 50 Hz, about 9.1 dB within the range of 250 Hz according to EN 1793-2 standard (Lab Highlights Resonance phenomenon in IQFSCAB can reduce noise pollution. The Stopping and Absorbing of the low-frequency noise is difficult. Noise pollution is one of the most important environmental challenges in many countries. New barriers have added a number of new strategies to previous studies. Our technique shows a clear advantage to resonance at frequencies below 100 Hz without adsorbent usage. Three mechanisms have been used in this scatterer model including resonance phenomenon, BG and inner-fractal-like structure without absorption mechanism.

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Noise attenuation performance improvement by adding Helmholtz resonators on the periodic ducted Helmholtz resonator system

Cited by 36 publications

References 19 publications

Optimized reactive silencers composed of closely-spaced elongated side-branch resonators

Optimized reactive silencers composed of closely-spaced elongated side-branch resonators

Optimized reactive silencers with narrow side-branch tubes

Designing, constructing and testing of a new generation of sound barriers

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