NDLI: Jet noise scaling in dual stream nozzles

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Jet noise scaling in dual stream nozzles

Content Provider	NASA Technical Reports Server (NTRS)
Author	Khavaran Sr., Abbas Bridges Sr., James
Copyright Year	2010
Description	Power spectral laws in dual stream jets are studied by considering such flows a superposition of appropriate single-stream coaxial jets. Noise generation in each mixing region is modeled using spectral power laws developed earlier for single stream jets as a function of jet temperature and observer angle. Similarity arguments indicate that jet noise in dual stream nozzles may be considered as a composite of four single stream jets representing primary/secondary, secondary/ambient, transition, and fully mixed zones. Frequency filter are designed to highlight spectral contribution from each jet. Predictions are provided at an area ratio of 2.0--bypass ratio from 0.80 to 3.40, and are compared with measurements within a wide range of velocity and temperature ratios. These models suggest that the low frequency noise in unheated jets is dominated by the fully mixed region at all velocity ratios, while the high frequency noise is dominated by the secondary when the velocity ratio is larger than 0.80. Transition and fully mixed jets equally dominate the low frequency noise in heated jets. At velocity ratios less than 0.50, the high frequency noise from primary/bypass becomes a significant contributing factor similar to that in the secondary/ambient jet.
File Size	5527692
Page Count	25
File Format	PDF
Alternate Webpage(s)	http://archive.org/details/NASA_NTRS_Archive_20110000527
Archival Resource Key	ark:/13960/t2d849n6g
Language	English
Publisher Date	2010-11-01
Access Restriction	Open
Subject Keyword	Acoustics Bypass Ratio Jet Aircraft Noise Temperature Ratio Laws Aerodynamic Noise Spectra High Frequencies Noise Generators Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science
Content Type	Text
Resource Type	Article

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