Technical Note. Effect of Liner Characteristics on the Acoustic Performance of Duct Systems

Othmani, Chokri; Hentati, Taissir; Taktak, Mohamed; Elnady, Tamer; Fakhfakh, Tahar; Haddar, Mohamed

doi:10.1515/aoa-2015-0014

Cited by 10 publications

(6 citation statements)

References 20 publications

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“…It presents an intrinsic characteristic of the duct element. For this, many researchers [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] have focused their attention on the use of the scattering matrix in their studies. In these studies, this matrix has been obtained from experimental and theoretical methods.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the Uncertainties propagation in the measurement of the scattering matrix of a duct containing porous material

Hannachi,

Trabelsi,

Taktak

et al. 2023

Preprint

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The objective of a theoretical simulation of an experiment is the identification of the experience parameters which are the most sensitive to errors to take them into account during the measurement and to reduce their corresponding errors. In this study, a simulation of the experiment procedure of measurement of the scattering matrix and the acoustic power attenuation of a duct element containing porous material is presented. The influence of the errors of measurement parameters like the separation distance, the length of the porous material and the modulus of the incident pressure on the measured quantities (scattering matrix coefficients and the acoustic power attenuation) is evaluated using the Monte Carlo technique. This method is considered as a benchmark for examining uncertainty diffusion on theoretical methods. The results of the uncertainty simulation are used to determine the 95% confidence intervals and the maximum and minimum errors for each measured parameter. The obtained results show that errors on the estimation of the length of the porous material has a great influence on the transmission and reflection coefficients as well as the acoustic power attenuation of the studied duct. For the other parameters, their effects are negligible.

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Section: Introductionmentioning

confidence: 99%

Simulation of the Uncertainties propagation in the measurement of the scattering matrix of a duct containing porous material

Hannachi,

Trabelsi,

Taktak

et al. 2023

Preprint

Self Cite

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“…Currently, porous liners can be modelled using the normal impedance (Bauer, 1977; Dhief et al, 2020; Othmani et al, 2015; Troian et al, 2017; Tuasikal et al, 2021; Tounsi, 2022) or a cavity with the equivalent fluid (Hou, 2020; Jiang and Wang, 2020; Li et al, 2019; Satcunanathan et al, 2019; Qiu et al, 2020a; Qiu et al, 2020b). However, the normal impedance is not sufficient to characterize the acoustic behaviour of a porous liner.…”

Section: Introductionmentioning

confidence: 99%

An investigation on the modelling of a finite porous liner for the sound propagation in a rectangular duct

Song

Yuan

et al. 2022

Journal of Vibration and Control

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Acoustic liners take an essential role in the noise attenuation in ducts. In this work, the multimodal method based on the finite-difference method is extended to predict the acoustic field in a rectangular duct lined with a finite porous material and validated by the experiment. A modified immersed interface method is developed for the air–porous interface problem in the extended multimodal method without flow. When the flow exists, the treatments of the air–porous interface problem and the continuity of pressure between the wall and liner are also given. Three ways of describing the porous liner using the surface impedance at normal incidence named normal impedance, the surface impedance at grazing incidence named shear impedance and a cavity filled with the equivalent fluid of porous material are introduced. The comparison among the three ways reveals that the extended method of treating liners using a cavity filled with the equivalent fluid is more accurate for the acoustic evaluation of porous liners. The analysis finds that the shear impedance can reasonably present the influence of porous material during the comparisons of transmission loss curves of the liners with different lengths and depths at different Mach numbers. In most cases, the prediction by the shear impedance is closer to that simulated by the cavity filled with porous material than the normal impedance. Normal impedance is hardly utilized to describe the porous material and is only reliable when the cavity is very short and deep.

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“…In a previous work, Othmani et al (2015) used this method to evaluate the effect of liner characteristics on the acoustic power attenuation of lined duct, then Masmoudi et al (2017) investigated the effect of geometry and impedance on the acoustic behavior of wall and porous material lined duct but using the simple model of Delany-Bazely which depends only on the flow resistivity. This was carried out for two configurations of duct diameter increase and duct diameter decrease with liner composed of a porous material and a perforated plate.…”

Section: Introductionmentioning

confidence: 99%

Archives of Acoustics

Tounsi,

Taktak,

Dhief

et al. 2022

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Duct silencers provide effective noise reduction for heating, ventilation and air conditioning systems. These silencers can achieve an excellent sound attenuation through the attributes of their design. The reactive silencer works on the principle of high reflection of sound waves at low frequencies. On the other hand, the dissipative silencer works on the principle of sound absorption, which is very effective at high-frequencies. Combining these two kinds of silencers allowed covering the whole frequency range. In this paper, the effect of liner characteristics composed of a perforated plate backed by a porous material and geometry discontinuities on the acoustic power attenuation of lined ducts is evaluated. This objective is achieved by using a numerical model to compute the multimodal scattering matrix, thus allowing deducing the acoustic power attenuation. The numerical results are obtained for six configurations, including cases of narrowing and widening of a radius duct with sudden or progressive discontinuities. Numerical acoustic power attenuation shows the relative influence of the variation in the values of each parameter of the liner, and of each type of radius discontinuities of ducts.

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Technical Note. Effect of Liner Characteristics on the Acoustic Performance of Duct Systems

Cited by 10 publications

References 20 publications

Simulation of the Uncertainties propagation in the measurement of the scattering matrix of a duct containing porous material

Simulation of the Uncertainties propagation in the measurement of the scattering matrix of a duct containing porous material

An investigation on the modelling of a finite porous liner for the sound propagation in a rectangular duct

Archives of Acoustics

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