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The Effect of Non-Harmonic Active Twist Actuation on BVI NoiseThe results of a computational study examining the effects of non-harmonic active-twist control on blade-vortex interaction (BVI) noise for the Apache Active Twist Rotor are presented. Rotor aeroelastic behavior was modeled using the Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics code and the rotor noise was predicted using the acoustics code PSU-WOPWOP. The application of non-harmonic active-twist inputs to the main rotor blade system comprised three parameters: azimuthal location to start actuation, azimuthal duration of actuation, and magnitude of actuation. The acoustic analysis was conducted for a single low-speed flight condition of advance ratio mu=0.14 and shaft angle-of-attack, a(sub s)=+6deg. BVI noise levels were predicted on a flat plane of observers located 1.1 rotor diameters beneath the rotor. The results indicate significant reductions of up to 10dB in BVI noise using a starting azimuthal location for actuation of 90?, an azimuthal duration of actuation of 90deg, and an actuation magnitude of +1.5 ft-lb.
Document ID
20110011563
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Fogarty, David E.
(National Inst. of Aerospace Associates Hampton, VA, United States)
Wilbur, Matthew L.
(Army Research Lab. Hampton, VA, United States)
Sekula, Martin K.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 25, 2013
Publication Date
May 3, 2011
Subject Category
Acoustics
Report/Patent Number
NF1676L-12015
Meeting Information
Meeting: AHS International 67th Annual Forum and Technology Display
Location: Virginia Beach, VA
Country: United States
Start Date: May 3, 2011
End Date: May 5, 2011
Funding Number(s)
WBS: WBS 877868.02.07.07.03.02.01
Distribution Limits
Public
Copyright
Other

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