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Advances in tilt rotor noise predictionThe two most serious tilt rotor external noise problems, hover noise and blade-vortex interaction noise, are studied. The results of flow visualization and inflow velocity measurements document a complex, recirculating highly unsteady and turbulent flow due to the rotor-wing-body interactions characteristic of tilt rotors. The wing under the rotor is found to obstruct the inflow, causing a deficit in the inflow velocities over the inboard region of the rotor. Discrete frequency harmonic thickness and loading noise mechanisms in hover are examined by first modeling tilt rotor hover aerodynamics and then applying various noise prediction methods using the WOPWOP code. The analysis indicates that the partial ground plane created by the wing below the rotor results in a primary sound source for hover.
Document ID
19930035187
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
George, A. R.
(NASA Ames Research Center Moffett Field, CA, United States)
Coffen, C. D.
(NASA Ames Research Center Moffett Field, CA, United States)
Ringler, T. D.
(Cornell Univ. Ithaca, NY, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1992
Publication Information
Publication: In: DGLR(AIAA Aeroacoustics Conference, 14th, Aachen, Germany, May 11-14, 1992, Proceedings. Vol. 2 (A93-19126 05-71)
Publisher: Deutsche Gesellschaft fuer Luft- und Raumfahrt
Subject Category
Acoustics
Accession Number
93A19184
Funding Number(s)
CONTRACT_GRANT: NAG2-554
CONTRACT_GRANT: NAS1-19000
CONTRACT_GRANT: NAS1-19145
Distribution Limits
Public
Copyright
Other

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