Estimating viscous losses in recycled granular microparticles : a time-domain wave decomposition impedance tube with boundary condition approximation

Železnik, Anže (avtor), Čurović, Luka (avtor), Murovec, Jure (avtor), Cerkovnik, Nejc (avtor), Prezelj, Jurij (avtor)

The sound absorption coefficient of a material represents the fraction of acoustic energy not reflected from its surface. The absorption is influenced by viscous losses in porous structures and sample resonances. This study proposes a novel method for measuring absorption coefficients in extended impedance tubes, specifically designed to distinguish between viscous losses and resonances, but can also be used to estimate the sound absorption coefficient in a standard impedance tube. The method is based on a time-domain wave decomposition for its simplicity of use and ability to visualize sound impulse reflections, revealing reflections of sound within the sample. A long vertical impedance tube was used to achieve sufficient separation of the sound impulses. Random noise was used as the excitation signal and spectral division deconvolution was used to calculate the sound wave impulses in the impedance tube. The proposed method was validated against the transfer function method using samples of rock wool, reconstituted foam, and polyether foam. The advantage of the proposed method was demonstrated on measurements of several granular fractions of recycled silica sand to determine the granule sizes where the main mechanism of sound absorption is viscous losses as opposed to resonances. It was found that the sound absorption caused by viscous losses is greatest for granule diameters around 500 μm.

• Jezik: Angleški jezik
• Ključne besede: absorption coefficient, impedance tubes, time-domain wave decomposition, deconvolution, granular materials
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FS - Fakulteta za strojništvo
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2025
• Št. strani: 11 str.
• Številčenje: Vol. 228, [art. no.] 110372
• PID: 20.500.12556/RUL-164583
• UDK: 534/535
• ISSN pri članku: 0003-682X
• DOI: 10.1016/j.apacoust.2024.110372
• COBISS.SI-ID: 213564419
• Datum objave v RUL: 04.11.2024

Gradivo je del revije

• Naslov: Applied acoustics
• Skrajšan naslov: Appl. Acoust.
• Založnik: Elsevier Science
• ISSN: 0003-682X
• COBISS.SI-ID: 24982016

Licence

• Licenca: CC BY-NC-ND 4.0, Creative Commons Priznanje avtorstva-Nekomercialno-Brez predelav 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by-nc-nd/4.0/deed.sl
• Opis: Najbolj omejujoča licenca Creative Commons. Uporabniki lahko prenesejo in delijo delo v nekomercialne namene in ga ne smejo uporabiti za nobene druge namene.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: koeficient absorpcije, impedančne cevi, valovna dekompozicija v časovni domeni, dekonvolucija, granulirani materiali

Projekti

• Financer: ARIS - Javna agencija za znanstvenoraziskovalno in inovacijsko dejavnost Republike Slovenije
• Številka projekta: P2-0401 (B)
• Naslov: Energy engineering