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Accession Number N20120010289
Title Framework for Simulation of Aircraft Flyover Noise Through a Non-Standard Atmosphere.
Publication Date Jun 2012
Media Count 17p
Personal Author D. G. Simons H. G. Visser M. Arntzen S. A. Rizzi
Abstract This paper describes a new framework for the simulation of aircraft flyover noise through a non-standard atmosphere. Central to the framework is a ray-tracing algorithm which defines multiple curved propagation paths, if the atmosphere allows, between the moving source and listener. Because each path has a different emission angle, synthesis of the sound at the source must be performed independently for each path. The time delay, spreading loss and absorption (ground and atmosphere) are integrated along each path, and applied to each synthesized aircraft noise source to simulate a flyover. A final step assigns each resulting signal to its corresponding receiver angle for the simulation of a flyover in a virtual reality environment. Spectrograms of the results from a straight path and a curved path modeling assumption are shown. When the aircraft is at close range, the straight path results are valid. Differences appear especially when the source is relatively far away at shallow elevation angles. These differences, however, are not significant in common sound metrics. While the framework used in this work performs off-line processing, it is conducive to real-time implementation.
Keywords Aeroacoustics
Aerodynamic noise
Aircraft noise
Elevation angle
Noise generators
Ray tracing
Real time operation
Reference atmospheres
Time lag

Source Agency National Aeronautics and Space Administration
NTIS Subject Category 46A - Acoustics
51A - Aerodynamics
Corporate Author National Aeronautics and Space Administration, Hampton, VA. Langley Research Center.
Document Type Conference proceedings
Title Note N/A
NTIS Issue Number 1226
Contract Number N/A

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