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Localized, Non-Harmonic Active Flap Motions for Low Frequency In-Plane Rotor Noise ReductionA first-of-its-kind demonstration of the use of localized, non-harmonic active flap motions, for suppressing low frequency, in-plane rotor noise, is reported in this paper. Operational feasibility is verified via testing of the full-scale AATD/Sikorsky/UTRC active flap demonstration rotor in the NFAC's 40- by 80-Foot anechoic wind tunnel. Effectiveness of using localized, non-harmonic active flap motions are compared to conventional four-per-rev harmonic flap motions, and also active flap motions derived from closed-loop acoustics implementations. All three approaches resulted in approximately the same noise reductions over an in-plane three-by-three microphone array installed forward and near in-plane of the rotor in the nearfield. It is also reported that using an active flap in this localized, non-harmonic manner, resulted in no more that 2% rotor performance penalty, but had the tendency to incur higher hub vibration levels.
Document ID
20120010107
Acquisition Source
Ames Research Center
Document Type
Conference Paper
External Source(s)
hdl:http://handle.dtic.mil/100.2/ADA558227
Authors
Sim, Ben W. (Army Research Development and Engineering Command Moffett Field, CA, United States)
Potsdam, Mark (Army Research Development and Engineering Command Moffett Field, CA, United States)
Kitaplioglu, Cahit (NASA Ames Research Center Moffett Field, CA, United States)
LeMasurier, Philip (Sikorsky Aircraft Corp. Stratford, CT, United States)
Lorber, Peter (Sikorsky Aircraft Corp. Stratford, CT, United States)
Andrews, Joseph (Sikorsky Aircraft Corp. Stratford, CT, United States)
Date Acquired
August 25, 2013
Publication Date
May 1, 2012
Subject Category
Aircraft Design, Testing And Performance
Report/Patent Number
AD-A558227
ARC-E-DAA-TN4949
Meeting Information
Meeting: American Helicopter Society 68th Annual Forum
Location: Fort Worth, TX
Country: United States
Start Date: May 1, 2012
End Date: May 3, 2012
Funding Number(s)
CONTRACT_GRANT: W911W6-08-2-0004
Distribution Limits
Public
Copyright
Public Use Permitted.

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