Complex frequency analysis and source of losses in rectangular sonic black holes

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21230%2F24%3A00370486" target="_blank" >RIV/68407700:21230/24:00370486 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1016/j.jsv.2023.118107" target="_blank" >https://doi.org/10.1016/j.jsv.2023.118107</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.jsv.2023.118107" target="_blank" >10.1016/j.jsv.2023.118107</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Complex frequency analysis and source of losses in rectangular sonic black holes

Popis výsledku v původním jazyce

The amount and practical source of losses required by rectangular sonic black holes in air to effectively absorb low-frequency sound are analyzed numerically and experimentally. In the sole presence of viscothermal losses, only high-order (high frequency) Fabry-Perrot resonances are likely to be critically coupled in realistic rectangular sonic black holes. This results in sharp absorption peaks that do not reach unity at low frequencies, because the quality factors of the associated resonances are high. To avoid these drawbacks, slits of rectangular sonic black holes are partially filled with porous materials so that a profile of porous filled slits is superimposed on the sonic black hole profile itself. The improvement in the absorption coefficient is significant, particularly at frequencies below the viscous/inertial transition frequency of the porous material. This transition frequency is assumed to be the limit of possible perfect absorption of the bulk porous material layer. The numerical results are supported by experimental results, which also show that the vibrations of the plates forming the acoustic black hole must be considered with caution.

Název v anglickém jazyce

Complex frequency analysis and source of losses in rectangular sonic black holes

Popis výsledku anglicky

The amount and practical source of losses required by rectangular sonic black holes in air to effectively absorb low-frequency sound are analyzed numerically and experimentally. In the sole presence of viscothermal losses, only high-order (high frequency) Fabry-Perrot resonances are likely to be critically coupled in realistic rectangular sonic black holes. This results in sharp absorption peaks that do not reach unity at low frequencies, because the quality factors of the associated resonances are high. To avoid these drawbacks, slits of rectangular sonic black holes are partially filled with porous materials so that a profile of porous filled slits is superimposed on the sonic black hole profile itself. The improvement in the absorption coefficient is significant, particularly at frequencies below the viscous/inertial transition frequency of the porous material. This transition frequency is assumed to be the limit of possible perfect absorption of the bulk porous material layer. The numerical results are supported by experimental results, which also show that the vibrations of the plates forming the acoustic black hole must be considered with caution.

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

2024

Kód důvěrnosti údajů

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

Název periodika

Journal of Sound and Vibration

ISSN

0022-460X

e-ISSN

1095-8568

Svazek periodika

571

Číslo periodika v rámci svazku

únor

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

7

Strana od-do

—

Kód UT WoS článku

001109663700001

EID výsledku v databázi Scopus

2-s2.0-85175318986