Abstract
The sound absorption and the surface impedance of a micro-perforated panel (MPP) backed by a trapezoid acoustic cavity with varying depth are numerically investigated. The coupled acoustic problem between the MPP and the acoustic cavity is formulated using a modal expansion method, which allows the determination of the acoustic pressure and velocity over the MPP surface. The validity of the solution is examined by comparing the predicted sound absorption curves with existing results provided by literature in a special case where a commonly used MPP absorber is involved. Numerical results based on the verified model reveal that, around the first cavity resonance, the irregular-shaped MPP absorber demonstrates similar sound absorption characteristics as that of a regular one having the same depth. However, the irregular-shaped MPP absorber can achieve a good/moderate sound absorption level in between the first and second resonances, as opposed to conventional MPP absorbers with constant cavity depth for which the sound absorption is usually negligible. Further investigation shows that this phenomenon is caused by the local resonances occurring in the irregular-shaped cavity. This phenomenon can be further explored for improving the acoustic performance of MPP absorbers.
Original language | English |
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Title of host publication | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 |
Pages | 1004-1012 |
Number of pages | 9 |
Volume | 2 |
Publication status | Published - 1 Dec 2009 |
Event | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 - Ottawa, ON, Canada Duration: 23 Aug 2009 → 26 Aug 2009 |
Conference
Conference | 38th International Congress and Exposition on Noise Control Engineering 2009, INTER-NOISE 2009 |
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Country/Territory | Canada |
City | Ottawa, ON |
Period | 23/08/09 → 26/08/09 |
ASJC Scopus subject areas
- Acoustics and Ultrasonics