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Application of an Aligned and Unaligned Signal Processing Technique to Investigate Tones and Broadband Noise in Fan and Contra-Rotating Open Rotor Acoustic SpectraThe study of noise from a two-shaft contra-rotating open rotor (CROR) is challenging since the shafts are not phase locked in most cases. Consequently, phase averaging of the acoustic data keyed to a single shaft rotation speed is not meaningful. An unaligned spectrum procedure that was developed to estimate a signal coherence threshold and reveal concealed spectral lines in turbofan engine combustion noise is applied to fan and CROR acoustic data in this paper (also available as NASA/TM-2015-218865). The NASA Advanced Air Vehicles Program, Advanced Air Transport Technology Project, Aircraft Noise Reduction Subproject supported the current work. The fan and open rotor data were obtained under previous efforts supported by the NASA Quiet Aircraft Technology (QAT) Project and the NASA Environmentally Responsible Aviation (ERA) Project of the Integrated Systems Research Program in collaboration with GE Aviation, respectively. The overarching goal of the Advanced Air Transport (AATT) Project is to explore and develop technologies and concepts to revolutionize the energy efficiency and environmental compatibility of fixed wing transport aircrafts. These technological solutions are critical in reducing the impact of aviation on the environment even as this industry and the corresponding global transportation system continue to grow.
Document ID
20150023101
Acquisition Source
Glenn Research Center
Document Type
Presentation
Authors
Miles, Jeffrey Hilton
(NASA Glenn Research Center Cleveland, OH United States)
Hultgren, Lennart S.
(NASA Glenn Research Center Cleveland, OH United States)
Date Acquired
December 15, 2015
Publication Date
October 25, 2015
Subject Category
Acoustics
Aircraft Propulsion And Power
Report/Patent Number
ISABE 2015-20243
GRC-E-DAA-TN27580
Meeting Information
Meeting: International Society of Airbreathing Engines (ISABE 2015)
Location: Phoenix, AZ
Country: United States
Start Date: October 25, 2015
End Date: October 30, 2015
Sponsors: International Society for Air Breathing Engines (ISABE)
Funding Number(s)
WBS: WBS 081876.02.03.50.03.06
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
Aeroacoustics
Noise
Turbomachinery
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