Rotorcraft blade/vortex interaction noise - Its generation, radiation, and controlRecent results are presented from several research efforts aimed at the understanding of rotorcraft blade-vortex interaction noise generation, directivity, and control. The results are based on work performed by researches at the NASA Langley Research Center, both alone and in collaboration with other research organizations. Based on analysis of a simplified physical model, the critical parameters controlling the noise generation are identified. Detailed mapping of the acoustic radiation field reveals the extreme sensitivity of directivity to rotor advance ratio and disk attitude. A means of controlling blade-vortex interaction noise by higher harmonic pitch control is discussed.
Document ID
19910039717
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Preisser, J. S. (NASA Langley Research Center Hampton, VA, United States)
Brooks, T. F. (NASA Langley Research Center Hampton, VA, United States)
Martin, R. M. (NASA Langley Research Center Hampton, VA, United States)