HHC study in the DNW to reduce BVI noise - An analysisThe noise of an aeroelastically scaled helicopter rotor has been studied in the German-Dutch wind tunnel in order to assess the utility of higher-harmonic control (HHC) in reducing blade-vortex interaction (BVI) noise. Acoustic data are presented for 3/rev, 4/rev, and 5/rev HHC, as applied to a typical landing approach rotor operating condition; noise reduction of up to 6 dB were found for advancing-blade BVI noise radiating upstream of the rotor, as well as for retreating blade BVI noise radiating below and downstream of the rotor.
Document ID
19930045408
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Brooks, Thomas F. (NASA Langley Research Center Hampton, VA, United States)
Booth, Earl R., Jr. (NASA Langley Research Center Hampton, VA, United States)
Boyd, D. D., Jr. (NASA Langley Research Center Hampton, VA, United States)
Splettstoesser, Wolf R. (NASA Langley Research Center Hampton, VA, United States)
Schultz, Klaus -J. (NASA Langley Research Center Hampton, VA, United States)