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Manipulation of upstream rotor leading edge vortex and its effects on counter rotating propeller noiseThe leading edge vortex of a counter rotating propeller (CRP) model was altered by using shrouds and by turning the upstream rotors to a forward sweep configuration. Performance, flow, and acoustic data were used to determine the effect of vortex impingement on the noise signature of the CRP system. Forward sweep was found to eliminate the leading edge vortex of the upstream blades. Removal of the vortex had little effect on the tone noise at the forward and rear blade passing frequencies (BPF's) but significantly altered both the sound pressure level and directivity of the interaction tone which occurs at the sum of the two BPF's. A separate manipulation of the leading edge vortex performed by installing shrouds of various inlet length on the CRP verified that diverting the vortex path increases the noise level of the interaction tone. An unexpected link has been established between the interaction tone and the leading edge vortex-blade interaction phenomenon.
Document ID
19930036137
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Squires, Becky
(North Carolina State Univ. Raleigh, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1993
Subject Category
Acoustics
Report/Patent Number
AIAA PAPER 93-0012
Meeting Information
Meeting: AIAA, Aerospace Sciences Meeting and Exhibit
Location: Reno, NV
Country: United States
Start Date: January 11, 1993
End Date: January 14, 1993
Sponsors: AIAA
Accession Number
93A20134
Funding Number(s)
CONTRACT_GRANT: NAG3-855
Distribution Limits
Public
Copyright
Other

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