Attenuation of sound in lined circular ducts
April 1975
| Main Authors: | , |
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| Other Authors: | |
| Format: | Technical Report |
| Published: |
Cambridge : Gas Turbine Laboratory, Massachusetts Institute of Technology, [1975]
2016
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| Online Access: | http://hdl.handle.net/1721.1/104405 |
| _version_ | 1826199138906144768 |
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| author | Cho, Young-chung Ingard, K. Uno |
| author2 | Massachusetts Institute of Technology. Gas Turbine Laboratory |
| author_facet | Massachusetts Institute of Technology. Gas Turbine Laboratory Cho, Young-chung Ingard, K. Uno |
| author_sort | Cho, Young-chung |
| collection | MIT |
| description | April 1975 |
| first_indexed | 2024-09-23T11:15:01Z |
| format | Technical Report |
| id | mit-1721.1/104405 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T11:15:01Z |
| publishDate | 2016 |
| publisher | Cambridge : Gas Turbine Laboratory, Massachusetts Institute of Technology, [1975] |
| record_format | dspace |
| spelling | mit-1721.1/1044052019-04-12T16:13:11Z Attenuation of sound in lined circular ducts Cho, Young-chung Ingard, K. Uno Massachusetts Institute of Technology. Gas Turbine Laboratory TJ778.M41 G24 no.120 Sound-waves -- Scattering April 1975 This is an addendum to Gas Turbine Laboratory Report No. 119. --Preface In the previous report, we have used approximate expressions for the wall impedance for the discussion of sound attenuation in lined circular ducts. For instance, Eq. (2.5) has been used for the wall impedance of a circular duct lined with a resonator with a resistive screen, and Eq. (2.8) for a circular duct lined with a porous material. If the ratio of the duct radius to the liner thickness (D/L) is large and the sound frequency is large, the impedance given in Eq. (2.5) or Eq. (2.8) is a good approximation for a lined circular duct. However, when either one of these conditions is not fulfilled, the radial spread of the wave in the liner imposes some effects on the sound attenuation, whereas no wave spreading takes place in the liner of a rectangular duct. In this addendum we derive expressions for the wall impedance of lined circular ducts, accounting for the cylindrical spreading of the waves within the liner. The assumption of a locally reacting surface is still made. On the basis of the impedance thus obtained, the attenuation characteristics of a circular lined duct are computed for a wide range of parameters. This research was carried out in the Gas Turbine Laboratory, M.I.T., supported by the Office of Noise Abatement, Department of Transportation, under Grant DOT-OS-30011 2016-09-27T19:58:59Z 2016-09-27T19:58:59Z 1975 Technical Report http://hdl.handle.net/1721.1/104405 02085982 GTL report #120 GTL report #119 115 pages application/pdf Cambridge : Gas Turbine Laboratory, Massachusetts Institute of Technology, [1975] |
| spellingShingle | TJ778.M41 G24 no.120 Sound-waves -- Scattering Cho, Young-chung Ingard, K. Uno Attenuation of sound in lined circular ducts |
| title | Attenuation of sound in lined circular ducts |
| title_full | Attenuation of sound in lined circular ducts |
| title_fullStr | Attenuation of sound in lined circular ducts |
| title_full_unstemmed | Attenuation of sound in lined circular ducts |
| title_short | Attenuation of sound in lined circular ducts |
| title_sort | attenuation of sound in lined circular ducts |
| topic | TJ778.M41 G24 no.120 Sound-waves -- Scattering |
| url | http://hdl.handle.net/1721.1/104405 |
| work_keys_str_mv | AT choyoungchung attenuationofsoundinlinedcircularducts AT ingardkuno attenuationofsoundinlinedcircularducts |