On the role of resonance and thermoviscous losses in an implementation of “acoustic black hole” for sound absorption in air

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21230%2F22%3A00359147" target="_blank" >RIV/68407700:21230/22:00359147 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1016/j.wavemoti.2022.103039" target="_blank" >https://doi.org/10.1016/j.wavemoti.2022.103039</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.wavemoti.2022.103039" target="_blank" >10.1016/j.wavemoti.2022.103039</a>

Jazyk výsledku

angličtina

Název v původním jazyce

On the role of resonance and thermoviscous losses in an implementation of “acoustic black hole” for sound absorption in air

Popis výsledku v původním jazyce

In this work, we propose a mathematical model of a sound-absorbing structure for anechoic duct termination, commonly called the acoustic black hole. The structure consists of a set of rigid rings separated by narrow fluid-filled cavities. There are holes in the centers of the rings, whose radii smoothly vary along the structure. According to the previously published works, wave speed in this structure can theoretically decrease to zero value, which results in the reduction of the reflection coefficient. The proposed model is based on the linearized Navier–Stokes equations formulated in 2D axisymmetric cylindrical coordinates, which are solved numerically in the frequency domain employing the finite element method. This way, thermoviscous losses in the acoustic boundary layer adjacent to the fluid–solid interfaces, especially in the narrow cavities, are accounted for properly. The numerical results show that the absorption of acoustic energy in this structure is connected with resonances taking place in the cavities forming annular resonators, rather than with the acoustic wave slow-down. This effect has not been captured in the previously published models. It is shown that the geometrical details of the structure strongly influence its behavior, indicating the possibility of its optimization to serve as an efficient absorber of acoustic energy in a relatively wide frequency range.

Název v anglickém jazyce

On the role of resonance and thermoviscous losses in an implementation of “acoustic black hole” for sound absorption in air

Popis výsledku anglicky

In this work, we propose a mathematical model of a sound-absorbing structure for anechoic duct termination, commonly called the acoustic black hole. The structure consists of a set of rigid rings separated by narrow fluid-filled cavities. There are holes in the centers of the rings, whose radii smoothly vary along the structure. According to the previously published works, wave speed in this structure can theoretically decrease to zero value, which results in the reduction of the reflection coefficient. The proposed model is based on the linearized Navier–Stokes equations formulated in 2D axisymmetric cylindrical coordinates, which are solved numerically in the frequency domain employing the finite element method. This way, thermoviscous losses in the acoustic boundary layer adjacent to the fluid–solid interfaces, especially in the narrow cavities, are accounted for properly. The numerical results show that the absorption of acoustic energy in this structure is connected with resonances taking place in the cavities forming annular resonators, rather than with the acoustic wave slow-down. This effect has not been captured in the previously published models. It is shown that the geometrical details of the structure strongly influence its behavior, indicating the possibility of its optimization to serve as an efficient absorber of acoustic energy in a relatively wide frequency range.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10307 - Acoustics

Projekt

<a href="/cs/project/GA22-33896S" target="_blank" >GA22-33896S: Pokročilé metody řízení zvukových a elastických vlnových polí: akustické černé díry, metamateriály a funkčně gradované materiály</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2022

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Wave Motion

ISSN

0165-2125

e-ISSN

1878-433X

Svazek periodika

114

Číslo periodika v rámci svazku

103039

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

10

Strana od-do

—

Kód UT WoS článku

000841594100006

EID výsledku v databázi Scopus

2-s2.0-85135899825