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10楼的各门也太不够意思了，
呵呵，我找成教授要到了他的一篇比较详细的论文，建议大家去下载，
Sound absorption of a micro-perforated panel backed by an
irregular-shaped cavity
Chunqi Wanga and Li Chengb
Department of Mechanical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong
Jie Pan
School of Mechanical Engineering, The University of Western Australia, 35 Stirling Highway, Crawley,
Western Australia 6009, Australia
Ganghua Yu
Department of Mechanical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong
Received 23 April 2009; revised 6 October 2009; accepted 7 October 2009
In the pursuit of more effective noise control devices, the cavity backed micro-perforated panel
absorber CBMPPA is developed in this study. A CBMPPA differs from the conventional
micro-perforated panel MPP absorber in that the MPP is backed by a trapezoidal cavity, which
allows more effective vibroacoustic coupling between the MPP and the cavity. A two-dimensional
theoretical model is established and tested both numerically and experimentally. Based on the
verified theoretical model, sound absorption performance of a trapezoidal CBMPPA is investigated
numerically. Results show that the shape of the backing cavity can significantly alter the sound
absorption mechanisms and frequency distribution of overall sound absorption coefficient of the
absorber. Further analyses show that acoustic modes that are initially decoupled from the MPP in the
rectangular configuration are coupled with the air motion in the MPP, which accounts for the change
in absorption pattern of the trapezoidal CBMPPA. By the same token, it also provides the flexibility
for tuning the effective absorption range of the absorber. Due to the varying impedance matching
conditions, the absorption performance of the trapezoidal CBMPPA exhibits obvious local
characteristics over the MPP surface, which contrasts with the spatially uniform absorption in the
conventional MPP absorber. © 2009 Acoustical Society of America. DOI: 10.1121/1.3257590
It is an extension of Internoise-2009 paper, which contains more details. |
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发表于 2009-11-19 11:04
显身卡
下来了看不了
还是 不行 为什么
