Passive and active acoustic properties of a diaphragm at low Mach number

Trabelsi, H.; Zerbib, Nicolas; Ville, Jean‐Michel; Foucart, Félix

doi:10.3166/ejcm.20.49-71

Cited by 10 publications

(10 citation statements)

References 8 publications

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“…For silencer B, only a continuous increase of the TL is observed and discrepancies do not exceed 3 dB even when using only N = 5 layers. The presence of three small peaks at 325 Hz, 486 Hz and 583 Hz are caused by the vibration of the duct wall [23].…”

Section: Resultsmentioning

confidence: 99%

“…The measurements were performed on a test bench (Fig. 3) designed for the multimodal characterization of the acoustic properties of obstacles (the dissipative silencer is considered as an obstacle in this context) in the presence (or not) of a low Mach number flow [23]. The duct facility is a rigid rectangular duct of 0.2 m × 0.1 m section with an anechoic termination at either end.…”

Section: Test Bench and Experimental Proceduresmentioning

confidence: 99%

“…The results are given within the frequency band [200 Hz -3.5 kHz] which limits the number of propagative modes in the duct to a maximum of M s = 10. The 2M s -port scattering matrix, which contains the modal reflection and transmission coefficients, is measured using a multi-source method described in [23]. The experimental procedure is carried out for silencer A (Fig.…”

Section: Test Bench and Experimental Proceduresmentioning

confidence: 99%

See 2 more Smart Citations

On the Efficiency of Parallel Baffle-Type Silencers in Rectangular Ducts: Prediction and Measurement

Binois¹,

Perrey‐Debain²,

Lanfranchi³

et al. 2015

Acta Acustica united with Acustica

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To estimate the efficiency of parallel baffle-type silencers in rectangular ducts, a two-dimensional multi-layer model is presented for predicting their transmission loss. The approach takes into account an arbitrary number of bulk reacting baffles of finite length bounded at both ends by a metallic fairing. Each layer is described by a mean pressure, which allows computing a piecewise constant modal basis for the mean pressure over the cross section. The continuity between the incoming and outgoing waves is performed by axial mode matching at the inlet and outlet cross-sections of the baffle silencer. It is shown that the model is easy to implement and suitable for optimization purposes based on design parameters such as the height of each baffle, their relative positions in the duct, and material properties. Relatively complex configurations can be simulated with relatively modest computational effort. An experimental campaign was carried out on a reduced scale test bench for standard configurations. The numerical results are in good agreement with the measurements. Noise reduction performances are analyzed in terms of reflected and dissipated sound powers. Finally, more complex geometric configurations are simulated in order to examine the influence of the relative transverse and axial positions of each baffle as well as the effect of a resistive screen between the baffles and the airways.

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Section: Resultsmentioning

confidence: 99%

Section: Test Bench and Experimental Proceduresmentioning

confidence: 99%

Section: Test Bench and Experimental Proceduresmentioning

confidence: 99%

See 1 more Smart Citation

On the Efficiency of Parallel Baffle-Type Silencers in Rectangular Ducts: Prediction and Measurement

Binois¹,

Perrey‐Debain²,

Lanfranchi³

et al. 2015

Acta Acustica united with Acustica

View full text Add to dashboard Cite

show abstract

“…Measurements are made on a test bench (Fig. 3) designed for the acoustic multimodal characterization of test section in the presence (or not) of a low Mach number flow 31,50 . The duct facility is a rigid rectangular duct of 0. of M s = 10.…”

Section: B Test Bench and Experimental Proceduresmentioning

confidence: 99%

“…The duct facility is a rigid rectangular duct of 0. of M s = 10. The 2M s -port scattering matrix, which contains the modal reflection and transmission coefficients, is measured using a multi-source method described in 50 . The set-up is generally used to study transmission problems, see Fig.…”

Section: B Test Bench and Experimental Proceduresmentioning

confidence: 99%

A transverse isotropic equivalent fluid model combining both limp and rigid frame behaviors for fibrous materials

Nennig

Binois

Dauchez

et al. 2018

The Journal of the Acoustical Society of America

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Due to the manufacturing process, some fibrous materials like glasswool may be transversely isotropic (TI): fibers are mostly parallel to a plane of isotropy within which material properties are identical in all directions whereas properties are different along the transverse direction. The behavior of TI fibrous material is well described by the TI Biot's model, but it requires one to measure several mechanical parameters and to solve the TI Biot's equations. This paper presents an equivalent fluid model that can be suitable for TI materials under certain assumptions. It takes the form of a classical wave equation for the pressure involving an effective density tensor combining both limp and rigid frame behaviors of the material. This scalar wave equation is easily amenable to analytical and numerical treatments with a finite element method. Numerical results, based on the proposed model, are compared with experimental results obtained for two configurations with a fibrous material. The first concerns the absorption of an incident plane wave impinging on a fibrous slab and the second corresponds to the transmission loss of a splitter-type silencer in a duct. Both configurations highlight the effect of the sample orientation and give an illustration of the unusual TI behavior for fluids.

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Poroelastic lamellar metamaterial for sound attenuation in a rectangular duct

Nennig

Perrey‐Debain

et al. 2021

Applied Acoustics

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The sound attenuation of a silencer consisting of a lamella network made with melamine foam inserted in rectangular duct is investigated numerically and experimentally. The lamella arrangement is designed so that skeleton bending elastic resonances appear at low frequency. In addition to this phenomenon, viscothermal losses in the porous material ensure broadband attenuation. The lamella network provides a natural sub-wavelength resonator, without any other kind of inclusions, and create an easy to manufacture metamaterial with high tunability and broadband efficiency. Experimental transmission losses compare well with three dimensional finite element model obtained either on the whole silencer, either on a periodic cell. A parametric study is conducted on the periodic model to identify the effect of different geometrical parameters, like dimensions of the lamella and air gap, as well as physical parameters, like air flow resistivity, elastic modulus and loss factor of the poroelastic material, on the sound attenuation in the silencer.

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Passive and active acoustic properties of a diaphragm at low Mach number

Cited by 10 publications

References 8 publications

On the Efficiency of Parallel Baffle-Type Silencers in Rectangular Ducts: Prediction and Measurement

On the Efficiency of Parallel Baffle-Type Silencers in Rectangular Ducts: Prediction and Measurement

A transverse isotropic equivalent fluid model combining both limp and rigid frame behaviors for fibrous materials

Poroelastic lamellar metamaterial for sound attenuation in a rectangular duct

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