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Comparison of Tone Mode Measurements for a Forward Swept and Baseline Rotor FanA forward swept fan, designated the Quite High Speed Fan (QHSF), was tested in the NASA Glenn 9- by 15-foot Low Speed Wind Tunnel to investigate its noise reduction relative to a baseline fan of the same aerodynamic performance. The design objective of the QHSF was a 6 dB reduction in Effective Perceived Noise Level relative to the baseline fan at the takeoff condition. The design noise reduction was to be a result of lower levels of multiple pure tone noise due to the forward swept rotor, and lower rotor/stator interaction tone noise from a leaned stator. Although the design 6 dB reduction was observed in far-field measurements, the induct mode measurements revealed the reasons for goals. All of the noise reduction was from the blade passing tone and its harmonics and most of this was unexpectedly from rotor/strut interaction modes. The reason for large differences in rotor/strut noise sources could not be determined with certainty. The reductions in the multiple pure tone noise for the forward swept rotor were not observed. this reduction were not the ones related to the design
Document ID
20030063234
Acquisition Source
Glenn Research Center
Document Type
Technical Memorandum (TM)
Authors
Heidelberg, Laurence J. (NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
September 7, 2013
Publication Date
June 1, 2003
Subject Category
Aeronautics (General)
Report/Patent Number
NASA/TM-2003-212378
E-13953
AIAA Paper 2003-3293
NAS 1.15:212378
Meeting Information
Meeting: Ninth Aeroacoustics Conference and Exhibit
Location: Hilton Head, SC
Country: United States
Start Date: May 12, 2003
End Date: May 14, 2003
Sponsors: Confederation of European Aerospace Societies, American Inst. of Aeronautics and Astronautics
Funding Number(s)
WBS: WBS 22-781-30-12
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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