MIT Libraries logoDSpace@MIT

MIT
View Item 
  • DSpace@MIT Home
  • Department of Aeronautics and Astronautics
  • Gas Turbine Laboratory
  • Gas Turbine Laboratory Reports
  • View Item
  • DSpace@MIT Home
  • Department of Aeronautics and Astronautics
  • Gas Turbine Laboratory
  • Gas Turbine Laboratory Reports
  • View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.

Attenuation of sound in lined circular ducts

Author(s)
Cho, Young-chung; Ingard, K. Uno
Thumbnail
Download02085982.pdf (3.038Mb)
Other Contributors
Massachusetts Institute of Technology. Gas Turbine Laboratory
Metadata
Show full item record
Abstract
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.
Description
April 1975
 
This is an addendum to Gas Turbine Laboratory Report No. 119. --Preface
 
Date issued
1975
URI
http://hdl.handle.net/1721.1/104405
Publisher
Cambridge : Gas Turbine Laboratory, Massachusetts Institute of Technology, [1975]
Series/Report no.
GTL report #120GTL report #119

Collections
  • Gas Turbine Laboratory Reports

Browse

All of DSpaceCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

My Account

Login

Statistics

OA StatisticsStatistics by CountryStatistics by Department
MIT Libraries
PrivacyPermissionsAccessibilityContact us
MIT
Content created by the MIT Libraries, CC BY-NC unless otherwise noted. Notify us about copyright concerns.