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Shock associated noise of inverted-profile coannular jets. II - Condition for minimum noise. III - Shock structure and noise characteristicThe generation of noise by the shock-turbulence interaction with shock cells in an inverted-profile coannular jet with nozzle exit velocity aligned with the jet axis is investigated analytically, interpreting the optical measurements of Tanna et al. (1985). The noise-intensity minimum at slightly supersonic primary-flow velocities is related to the weakness of the primary-stream shock-cell structure and the lack of such a pattern in the outer fan stream. The discrepancies between this finding and those of Dosanjh et al. (1977 and 1978) are attributed to nozzle design, the definition of minimum noise, and different interpretative approaches. A first-order shock-cell model is then developed to derive formulas for the peak frequencies and the scaling of noise intensity. The results of computations using these formulas are presented in graphs and found to be in good agreement with the experimental data.
Document ID
19850053149
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Tam, C. K. W.
(Florida State University Tallahassee, FL; Lockheed-Georgia Co., Marietta, GA, United States)
Tanna, H. K.
(Lockheed-Georgia Co. Marietta, GA, United States)
Date Acquired
August 12, 2013
Publication Date
January 8, 1985
Publication Information
Publication: Journal of Sound and Vibration
Volume: 98
ISSN: 0022-460X
Subject Category
Acoustics
Accession Number
85A35300
Funding Number(s)
CONTRACT_GRANT: NAS1-15971
Distribution Limits
Public
Copyright
Other

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