Abstract
A method for estimating achievable attenuation for broadband noise in an inlet duct, consistent with Dyer's suggestion that an appropriate model includes all propagating acoustic modes at equal power and random phase, is proposed. Broadband noise is represented in a frequency domain analysis by a statistical distribution of propagating duct modes. The required number of modes is estimated by Rice's approximation method and verified in FEM modeling. For each propagating circumferential mode propagating radial modes have equal acoustic power and random phase. Source acoustic power is distributed among circumferential modes according to the number of propagating radial modes in the circumferential mode. A new parallel architecture version of an established propagation code, designed to include all propagating modes on a statistical basis, is described. Examples for prediction of acoustic power attenuation of broadband noise at low and moderate frequencies are used to estimate attenuation achievable by acoustic treatment designed for multiple pure tones. Comparison is made with a previously reported approach, based on equipartition of acoustic power in each circumferential mode, but distributing circumferential modes based on source intensity at a measurement point. Conclusions drawn from the two methods are similar, though differ in detail.
Recommended Citation
W. Eversman, "A Statistical Approach to Broadband Noise Suppression," 22nd AIAA/CEAS Aeroacoustics Conference, 2016, American Institute of Aeronautics and Astronautics, Jan 2016.
The definitive version is available at https://doi.org/10.2514/6.2016-2921
Department(s)
Mechanical and Aerospace Engineering
Publication Status
Full Access
International Standard Book Number (ISBN)
978-162410386-5
Document Type
Article - Conference proceedings
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2024 American Institute of Aeronautics and Astronautics, All rights reserved.
Publication Date
01 Jan 2016
