A study of Propfan propagation noiseA study of Propfan far-field noise is carried out based on geometrical acoustics theory. The analysis traces the acoustic rays and ray tube areas carrying the acoustic disturbances to the far-field. Sound attenuation due to nonlinear steepening, atmospheric absorption and turbulence scattering are also investigated. A comparison of our prediction methodology with experimental acoustics measurement shows good agreement. Geometrical decay and atmospheric absorption are identified as the primary noise attenuating mechanisms. Nonlinear effects are negligible. It is determined that the acoustic footprints of advanced propellers are dominated by caustics. Details of the formation of these caustics may provide a basis for future noise minimization efforts.
Document ID
19930040731
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Sim, Ben W.-C. (NASA Langley Research Center Hampton, VA, United States)
George, A. R. (Cornell Univ. Ithaca, NY, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1993
Subject Category
Acoustics
Report/Patent Number
AIAA PAPER 93-0602
Meeting Information
Meeting: AIAA, Aerospace Sciences Meeting and Exhibit