A Study on Sound Absorption Characteristics of Elastic Resonance Panel Considering Flow Environment

Author(s):  
Yo-Seb Choi ◽  
Suk-Yoon Hong ◽  
Jee-Hun Song ◽  
Hyun-Wung Kwon ◽  
Hee-Min Noh
2014 ◽  
Vol 76 ◽  
pp. 28-34 ◽  
Author(s):  
Kimihiro Sakagami ◽  
Yusaku Fukutani ◽  
Motoki Yairi ◽  
Masayuki Morimoto

2021 ◽  
Vol 263 (2) ◽  
pp. 4532-4537
Author(s):  
Toru Otsuru ◽  
Reiji Tomiku ◽  
Noriko Okamoto ◽  
Siwat Lawanwadeekul

The authors have been published a series of papers on a measurement method for sound absorption characteristics of materials using ensemble averaging technique, i.e., EA method. The papers' results included measurement mechanisms, measurement uncertainty, and so on. Herein, to examine adaptability, especially in in-situ conditions, the EA method is applied to measure absorption characteristics of materials installed in two gymnasiums. A glass-wool panel with the dimension of 0.5 m by 0.5 m by 0.05 m and with the density of 32 kg m^-3 was brought around and measured to check the measurement consistency. Several measurements were conducted during badminton plays were undergoing. Measured sound absorption coefficients revealed that most results agree well with those measured in reverberation rooms. Certain improvement is necessary for the specimen brought to the in-situ measurement to keep the consistency. The inconsistency is considered to originate from unstable conditions between the specimen and floor.


2021 ◽  
Author(s):  
Kimihiro Sakagami ◽  
Midori Kusaka ◽  
Takeshi Okuzono ◽  
Shigeyuki Kido ◽  
Daichi Yamaguchi

There are various measures currently in place to prevent the spread of COVID-19; however, in some cases, these can have an adverse effect on the acoustic environment in buildings. For example, transparent acrylic partitions are often used in eating establishments, meeting rooms, offices, etc., to prevent droplet infection. However, acrylic partitions are acoustically reflective; therefore, reflected sounds may cause acoustic problems such as difficulties in conversation or the leakage of conversation. In this study, we performed a prototyping of transparent acrylic partitions to which a microperforated panel (MPP) was applied for sound absorption while maintaining transparency. The proposed partition is a triple-leaf acrylic partition with a single acrylic sheet without holes between two MPP sheets, as including a hole-free panel is important to a possible droplet penetration. The sound absorption characteristics were investigated by measuring the sound absorption in a reverberation room. As the original prototype showed sound absorption characteristics with a gentle peak and low values due to the openings on the periphery, it was modified by closing the openings of the top and sides. The sound absorption performance was improved to some extent when the top and sides were closed, although there remains the possibility of further improvement. This time, only the sound absorption characteristics were examined in the prototype experiments. The effects during actual use will be the subject of future study.


2021 ◽  
Vol 28 (12) ◽  
Author(s):  
A. A. Mahmoud ◽  
E. A. Nasr ◽  
Sonia Zulfiqar ◽  
Muhammad Ilyas Sarwar ◽  
A. A. Maamoun

2020 ◽  
Vol 307 ◽  
pp. 291-296 ◽  
Author(s):  
Meifal Rusli ◽  
Fakhrur Rahman ◽  
Hendery Dahlan ◽  
Gusriwandi ◽  
Mulyadi Bur

A micro-perforated panel (MPP) works as a Helmholtz-type resonance absorber formed by an air-gab cavity in order to minimize the reflected sound effectively at a selective resonance frequency. Furthermore, the use of natural fibers as sound absorbing materials recently has attracted more attention because it is completely biodegradable, environmental friendly and more economical. In this paper, the combination of MPP and natural fiber as sound absorptive material is investigated. The MPP is made of a transparent acrylic board with 1.5 mm thickness and backed by a coconut fiber panel. The effect of the fiber panel that inserted in the air-gab cavity to the sound absorption characteristic of a single leaf MPP is observed. Sound absorption coefficient is measured by transfer function method using two microphones-impedance tube. It is found that the sandwich model of MPP backed by a coconut fiber changes the sound absorption characteristics of MPP by shifting the maximum absorption coefficient into the lower frequency and making a wider band of frequency absorption. Moreover, the air-gab cavity between MPP and fiber panel give fewer contribution to construct the MPP frequency resonant than the natural fiber panel one.


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