| Author: | Leung, Kwan-hao |
| Title: | Investigation of higher order mode transmission loss in a rectangular air duct with no flow |
| Degree: | M.Eng. |
| Year: | 2008 |
| Subject: | Hong Kong Polytechnic University -- Dissertations. Sound -- Transmission. Air ducts -- Noise control. |
| Department: | Department of Building Services Engineering |
| Pages: | xvi, 84, xiii leaves : ill. (some col.) ; 30 cm. |
| Language: | English |
| Abstract: | This dissertation examined, experimentally and theoretically, the higher order mode sound power transmission losses of single branching installed along a rectangular duct in stationary medium. Special efforts were made to develop the high order sound attenuation model, mathematically, which based on the predications of sound power transmission loss by plane wave theory. A set of duct together with single branch and anechoic terminations were designed and produced for experimental purpose. Using the advanced equipment such as frequency pulse analyzer and conditioning amplifier, measurement were conducted in the laboratory of Department of Building Services Engineering at The Hong Kong Polytechnic University. The transmission loss effect of the single branching duct was investigated experimentally. The study found that higher order sound transmission resulted more transmission loss than that on low frequency sound transmission. It has been showed that the single branching took away more acoustical energy at high order mode, and thus reduction of sound power transmission to downstream of the main duct occurred. Further investigations on high order transmission in flow condition should recommend for the provision of accurate and comprehensive information of this behavior for ductwork designers in reality. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| b22319979.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 6.95 MB | Adobe PDF | View/Open |
Copyright Undertaking
As a bona fide Library user, I declare that:
- I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
- I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
- I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.
Please use this identifier to cite or link to this item:
https://theses.lib.polyu.edu.hk/handle/200/3986