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On the attenuation of sound by three-dimensionally segmented acoustic liners in a rectangular duct
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Koch, W. |
| Copyright Year | 1979 |
| Description | Axial segmentation of acoustically absorbing liners in rectangular, circular or annual duct configurations is a very useful concept for obtaining higher noise attenuation with respect to the bandwidth of absorption as well as the maximum attenuation. As a consequence, advanced liner concepts are proposed which induce a modal energy transfer in both cross-sectional directions to further reduce the noise radiated from turbofan engines. However, these advanced liner concepts require three-dimensional geometries which are difficult to treat theoretically. A very simple three-dimensional problem is investigated analytically. The results show a strong dependence on the positioning of the liner for some incident source modes while the effect of three-dimensional segmentation appears to be negligible over the frequency range considered. |
| File Size | 1018517 |
| Page Count | 30 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19790019761 |
| Archival Resource Key | ark:/13960/t2w42jw8p |
| Language | English |
| Publisher Date | 1979-06-01 |
| Access Restriction | Open |
| Subject Keyword | Acoustics Sound Transmission Noise Reduction Linings Segments Turbofan Engines Acoustic Ducts Energy Transfer Acoustic Attenuation Wave Reflection Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
