Asymptotic modeling of Helmholtz resonators including thermoviscous effects

Brandão, Rodolfo; Schnitzer, Ory

doi:10.1016/j.wavemoti.2020.102583

Cited by 14 publications

(54 citation statements)

References 31 publications

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“…This way of considering the problem, which was proposed in [53,54,20,17], is an essential ingredient to reveal the resonant phenomena. From this perspective, our work shares similarities with [29,9,10] (see also references therein). On the other hand, we will observe in the asymptotic procedure that when ε tends to zero, everything happens like if punctual sources were located at the junction points between the resonators and the main part of the waveguide (see e.g.…”

Section: Introductionsupporting

confidence: 59%

Acoustic passive cloaking using thin outer resonators

Chesnel,

Heleine,

Nazarov

2021

Preprint

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We consider the propagation of acoustic waves in a 2D waveguide unbounded in one direction and containing a compact obstacle. The wavenumber is fixed so that only one mode can propagate. The goal of this work is to propose a method to cloak the obstacle. More precisely, we add to the geometry thin outer resonators of width ε and we explain how to choose their positions as well as their lengths to get a transmission coefficient approximately equal to one as if there were no obstacle. In the process we also investigate several related problems. In particular, we explain how to get zero transmission and how to design phase shifters. The approach is based on asymptotic analysis in presence of thin resonators. An essential point is that we work around resonance lengths of the resonators. This allows us to obtain effects of order one with geometrical perturbations of width ε. Various numerical experiments illustrate the theory.

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Section: Introductionsupporting

confidence: 59%

Acoustic passive cloaking using thin outer resonators

Chesnel,

Heleine,

Nazarov

2021

Preprint

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“…A similar approach could also be developed for three-dimensional hole resonators [32]. An analogous theory for acoustic Helmholtz resonators embedded in a wall and arrays thereof has recently been developed by two of us [26]. We conclude with comments regarding the generalised electromagnetic-acoustic analogy identified in this paper.…”

Section: Discussionmentioning

confidence: 82%

“…It is this observation, together with the above scaling rules, by which we have identified the distinguished scaling (2.15). We note that an alternative scaling analysis could be carried out based on energy-dissipation arguments [26].…”

Section: Asymptotic Analysis For a Single Slitmentioning

confidence: 99%

Boundary-layer effects on electromagnetic and acoustic extraordinary transmission through narrow slits

2020

Self Cite

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We study the problem of resonant extraordinary transmission of electromagnetic and acoustic waves through subwavelength slits in an infinite plate, whose thickness is close to a half-multiple of the wavelength. We build on the matched-asymptotics analysis of Holley & Schnitzer (2019 Wave Motion 91 , 102381 (doi:10.1016/j.wavemoti.2019.102381)), who considered a single-slit system assuming an idealized formulation where dissipation is neglected and the electromagnetic and acoustic problems are analogous. We here extend that theory to include thin dissipative boundary layers associated with finite conductivity of the plate in the electromagnetic problem and viscous and thermal effects in the acoustic problem, considering both single-slit and slit-array configurations. By considering a distinguished boundary-layer scaling where dissipative and diffractive effects are comparable, we develop accurate analytical approximations that are generally valid near resonance; the electromagnetic–acoustic analogy is preserved up to a single parameter that is provided explicitly for both scenarios. The theory is shown to be in excellent agreement with GHz-microwave and kHz-acoustic experiments in the literature.

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“…Several studies have discussed Helmholtz resonators as well as their influence on sound absorption and sound transmission loss (STL). Research conducted by Brandao and Schnitzer [14] created modeling about the acoustic performance of the Helmholtz resonator. The geometrical Helmholtz has been created with various long dimensions of the Helmholtz resonator neck.…”

Section: Water Hyacinth Based Composite and Ceramic Application In Architecturementioning

confidence: 99%

The Acoustical Performance of Water Hyacinth Based Porous-Ceramic Compared to the Biomass Fiber Composites for Architecture Application

Setyowati¹,

Hardiman²,

Grafiana³

2021

cea

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The hyacinth plant (Eichhornia crassipes) is an aquatic weed that causes the silting of swamps. The water hyacinth research was developed because of concerns over the threat of biodiversity in swamps by utilizing water hyacinth for ceramic and composite mixtures. This current research highlights the comparative acoustical performances of ceramic and composite with water hyacinth contents. Dried water hyacinth was added to the clay ceramic mixture with a weight percentage of 2, 6, 8, and 10 wt%. The ceramic dough was then shaped hexagonally with an interlock system and molded overlay respectively before burning and biscuits, while the composite dough consisted of 200 ml polyester resin: 25 mg water hyacinth: 20 ml catalyst. The acoustic test methods refer to ASTM 1050-98 and ASTM E2611-09 for sound absorption and sound transmission loss respectively. The result showed that the 8 wt% water hyacinth mixture of porous ceramic had an average absorption coefficient of 0.29 and a sound transmission loss of a wide range of frequencies with an average of 59.1 dB. Meanwhile, the resin composite has a poor average of sound absorption of 0.10 -0.11 and 58.08 -58.36 dB on its STL. The innovation of the water hyacinth-ceramic, however, had a promising character as a Helmholtz-based diffuser-absorber.

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Asymptotic modeling of Helmholtz resonators including thermoviscous effects

Cited by 14 publications

References 31 publications

Acoustic passive cloaking using thin outer resonators

Acoustic passive cloaking using thin outer resonators

Boundary-layer effects on electromagnetic and acoustic extraordinary transmission through narrow slits

The Acoustical Performance of Water Hyacinth Based Porous-Ceramic Compared to the Biomass Fiber Composites for Architecture Application

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