Comparison of Tone Mode Measurements for a Forward Swept and Baseline Rotor Fan
- Heidelberg, Laurence J.
- June 2003.
- Physical Description:
- 1 electronic document
- Restrictions on Access:
- Unclassified, Unlimited, Publicly available. and Free-to-read Unrestricted online access
- A 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
- NASA Technical Reports Server (NTRS) Collection.
- Document ID: 20030063234., NAS 1.15:212378., AIAA Paper 2003-3293., E-13953., NASA/TM-2003-212378., and Ninth Aeroacoustics Conference and Exhibit; 12-14 May 2003; Hilton Head, SC; United States.
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