Tip-path-plane angle effects on rotor blade-vortex interaction noise levels and directivityAcoustic data of a scale model BO-105 main rotor acquired in a large aeroacoustic wind tunnel are presented to investigate the parametric effects of rotor operating conditions on blade-vortex interaction (BVI) impulsive noise. Contours of a BVI noise metric are employed to quantify the effects of rotor advance ratio and tip-path-plane angle on BVI noise directivity and amplitude. Acoustic time history data are presented to illustrate the variations in impulsive characteristics. The directionality, noise levels and impulsive content of both advancing and retreating side BVI are shown to vary significantly with tip-path-plane angle and advance ratio over the range of low and moderate flight speeds considered.
Document ID
19890031543
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Burley, Casey L. (Planning Research Corp. Hampton, VA, United States)
Martin, Ruth M. (NASA Langley Research Center Hampton, VA, United States)