NDLI: Ejector noise suppression with auxiliary jet injection

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Ejector noise suppression with auxiliary jet injection

Content Provider	NASA Technical Reports Server (NTRS)
Author	Berman, Charles H. Andersen Jr., Otto P.
Copyright Year	1997
Description	An experimental program to reduce aircraft jet turbulence noise investigated the interaction of small auxiliary jets with a larger main jet. Significant reductions in the far field jet noise were obtained over a range of auxiliary jet pressures and flow rates when used in conjunction with an acoustically lined ejector. While the concept is similar to that of conventional ejector suppressors that use mechanical mixing devices, the present approach should improve thrust and lead to lower weight and less complex noise suppression systems since no hardware needs to be located in the main jet flow. A variety of auxiliary jet and ejector configurations and operating conditions were studied. The best conditions tested produced peak to peak noise reductions ranging from 11 to 16 dB, depending on measurement angle, for auxiliary jet mass flows that were 6.6% of the main jet flow with ejectors that were 8 times the main jet diameter in length. Much larger reductions in noise were found at the original peak frequencies of the unsuppressed jet over a range of far field measurement angles.
File Size	2268243
Page Count	54
File Format	PDF
Alternate Webpage(s)	http://archive.org/details/NASA_NTRS_Archive_19970025021
Archival Resource Key	ark:/13960/t5gb71j7k
Language	English
Publisher Date	1997-06-01
Access Restriction	Open
Subject Keyword	Acoustics Turbulence Jet Aircraft Noise Noise Reduction Research Aircraft Far Fields Flow Velocity Mechanical Devices Injection Complex Systems Suppressors Mass Flow Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science
Content Type	Text
Resource Type	Technical Report

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