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Effects of mean flow on duct mode optimum suppression ratesThe nature of the solution to the convected acoustic wave equation and associated boundary conditions for rectangular ducts containing uniform mean flow is examined in terms of the complex mapping between the wall admittance and characteristic mode eigenvalues. It is shown that the Cremer optimum suppression criteria must be modified to account for the effects of flow below certain critical values of the nondimensional frequency parameter of duct height divided by sound wavelength. The implications of these results on the design of low frequency suppressors are considered.
Document ID
19770003368
Document Type
Conference Paper
Authors
Kraft, R. E.
(General Electric Co. Philadelphia, PA, United States)
Wells, W. R.
(Cincinnati Univ.)
Date Acquired
August 8, 2013
Publication Date
January 1, 1976
Publication Information
Publication: NASA. Langley Res. Center Advan. in Eng. Sci., Vol. 3
Subject Category
Acoustics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19770003363Analytic PrimaryAdvances in Engineering Science, Volume 3