Beamforming is an imaging tool for the investigation of aeroacoustic phenomena and results in high-dimensional data that are broken down to spectra by integrating spatial regions of interest. This paper presents two methods that enable the automated identification of aeroacoustic sources in sparse beamforming maps and the extraction of their corresponding spectra to overcome the manual definition of regions of interest. The methods are evaluated on two scaled airframe half-model wind tunnel measurements and on a generic monopole source. The first relies on the spatial normal distribution of aeroacoustic broadband sources in sparse beamforming maps. The second uses hierarchical clustering methods. Both methods are robust to statistical noise and predict the existence, location, and spatial probability estimation for sources based on which regions of interest are automatically determined.
References
1.
Abramowitz
, M.
(1974
). Handbook of Mathematical Functions, with Formulas, Graphs, and Mathematical Tables
(Dover Publications
, New York
).2.
Ahlefeldt
, T.
(2013
). “Aeroacoustic measurements of a scaled half-model at high Reynolds numbers
,” AIAA J.
51
(12
), 2783
–2791
.3.
Ahlefeldt
, T.
(2017
). “Microphone array measurement in European transonic wind-tunnel at flight Reynolds numbers
,” AIAA J.
55
(1
), 36
–48
.4.
Antoni
, J.
(2012
). “A Bayesian approach to sound source reconstruction: Optimal basis, regularization, and focusing
,” J. Acoust. Soc. Am.
131
(4
), 2873
–2890
.5.
Bahr
, C. J.
, and Horne
, W. C.
(2015
). “Advanced background subtraction applied to aeroacoustic wind tunnel testing
,” in Proceedings of the 21st AIAA/CEAS Aeroacoustics Conference
, June 22–26, Dallas, TX.6.
Bahr
, C. J.
, Humphreys
, W. M.
, Ernst
, D.
, Ahlefeldt
, T.
, Spehr
, C.
, Pereira
, A.
, Leclère
, Q.
, Picard
, C.
, Porteous
, R.
, Moreau
, D.
, Fischer
, J. R.
, and Doolan
, C. J.
(2017
). “A comparison of microphone phased array methods applied to the study of airframe noise in wind-tunnel testing
,” in Proceedings of the 23rd AIAA/CEAS Aeroacoustics Conference
, June 5–9, Denver, CO.7.
Bianco
, M. J.
, Gerstoft
, P.
, Traer
, J.
, Ozanich
, E.
, Roch
, M. A.
, Gannot
, S.
, and Deledalle
, C. A.
(2019
). “Machine learning in acoustics: Theory and applications
,” J. Acoust. Soc. Am.
146
(5
), 3590
–3628
.8.
Blacodon
, D.
(2011
). “Array processing for noisy data: Application for open and closed wind-tunnels
,” AIAA J.
49
(1
), 55
–66
.9.
Campello
, R. J. G. B.
, Moulavi
, D.
, and Sander
, J.
(2013
). “Density-based clustering based on hierarchical density estimates
,” in Advances in Knowledge Discovery and Data Mining
(Springer
, Berlin
).10.
Dobrzynski
, W.
(2010
). “Almost 40 years of airframe noise research: What did we achieve?
,” J. Aircraft
47
(2
), 353
–367
.11.
Dobrzynski
, W.
, and Pott-Pollenske
, M.
(2001
). “Slat noise source studies for farfield noise prediction
,” in Proceedings of the 7th AIAA/CEAS Aeroacoustics Conference and Exhibit
, May 28–30, Maastricht, Netherlands.12.
Dong
, B.
, Antoni
, J.
, Pereira
, A.
, and Kellermann
, W.
(2016
). “Blind separation of incoherent and spatially disjoint sound sources
,” J. Sound Vib.
383
, 414
–445
.13.
Dong
, B.
, Antoni
, J.
, and Zhang
, E.
(2014
). “Blind separation of sound sources from the principle of least spatial entropy
,” J. Sound Vib.
333
(9
), 2643
–2668
.14.
Ernst
, D.
(2020
). “Akustischer Kohärenzverlust in Offenen Windkanälen Aufgrund Der Turbulenten Scherschicht” (“Acoustic coherence loss in open wind tunnels due to the turbulent shear layer”)
, Ph.D. thesis, Technische Universität Berlin
.15.
Goudarzi
, A.
, Spehr
, C.
, and Herbold
, S.
(2020
). “Expert decision support system for aeroacoustic classification from deconvolved beamforming maps
,” in Proceedings of the AIAA Aviation 2020 Forum
, June 15–19.16.
Guo
, Y. P.
, and Joshi
, M. C.
(2003
). “Noise characteristics of aircraft high lift systems
,” AIAA J.
41
(7
), 1247
–1256
.17.
Howe
, M. S.
(1982
). “On the generation of side-edge flap noise
,” J. Sound Vib.
80
(4
), 555
–573
.18.
19.
McInnes
, L.
, Healy
, J.
, and Astels
, S.
(2017
). “hdbscan: Hierarchical density based clustering
,” J. Open Source Softw.
2
(11
), 205
.20.
Merino-Martínez
, R.
, Sijtsma
, P.
, Rubio Carpio
, A.
, Zamponi
, R.
, Luesutthiviboon
, S.
, Malgoezar
, A.
, Snellen
, M.
, Schram
, C.
, and Simons
, D.
(2019a
). “Integration methods for distributed sound sources
,” Int. J. Aeroacoust.
18
, 444
–469
.21.
Merino-Martínez
, R.
, Sijtsma
, P.
, Snellen
, M.
, Ahlefeldt
, T.
, Antoni
, J.
, Bahr
, C. J.
, Blacodon
, D.
, Ernst
, D.
, Finez
, A.
, Funke
, S.
, Geyer
, T. F.
, Haxter
, S.
, Herold
, G.
, Huang
, X.
, Humphreys
, W. M.
, Leclère
, Q.
, Malgoezar
, A.
, Michel
, U.
, Padois
, T.
, Pereira
, A.
, Picard
, C.
, Sarradj
, E.
, Siller
, H.
, Simons
, D. G.
, and Spehr
, C.
(2019b
). “A review of acoustic imaging methods using phased microphone arrays
,” CEAS Aeronaut. J.
10
(1
), 197
–230
.22.
Müller
, E.-A.
(1979
). Mechanics of Sound Generation in Flows: IUTAM Symposium
(Springer-Verlag
, Berlin
).23.
Schwarz
, G.
(1978
). “Estimating the dimension of a model
,” Ann. Stat.
6
(2
), 461
–464
.24.
Sijtsma
, P.
(2004
). “Experimental techniques for identification and characterisation of noise sources
,” Technical Report NLR-TP-2004-165
(National Aerospace Laboratory NLR
, Amsterdam, Netherlands
).25.
Sijtsma
, P.
(2007
). “Clean based on spatial source coherence
,” Int. J. Aeroacoust.
6
, 357
–374
.26.
Zhang
, E.
, Antoni
, J.
, Dong
, B.
, and Snoussi
, H.
(2012
). “Bayesian space-frequency separation of wide-band sound sources by a hierarchical approach
,” J. Acoust. Soc. Am.
132
(5
), 3240
–3250
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