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Synthesizing coherence loss by atmospheric turbulence in virtual microphone array signals

Lincke, Dorothea and Schumacher, Timo and Pieren, Reto (2023) Synthesizing coherence loss by atmospheric turbulence in virtual microphone array signals. Journal of the Acoustical Society of America, 153 (1), pp. 456-466. Acoustical Society of America. doi: 10.1121/10.0016847. ISSN 0001-4966.

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Official URL: https://dx.doi.org/10.1121/10.0016847


Phased microphone array methods are increasingly used to localize and quantify noise sources of aircraft under flight condition. However, beamforming results suffer from loss of image resolution and corruption of sound levels due to atmospheric turbulence causing coherence loss between microphones. A synthesis method is presented that reproduces these effects in a virtual environment. Sound propagation through turbulent atmosphere is described by models by Ostashev and Wilson and by von Kármán turbulence spectra. Spatial coherence is calculated based on the parabolic equation for statistically inhomogeneous, isotropic turbulence. Decorrelation of signals is achieved by time-varying mixing of mutually independent signals with identical PSD based on coherence factors. The concept of auralization is employed to account for propagation delay, geometrical spreading, Doppler effect, air absorption, and ground effect. The application is demonstrated for a virtual 56 m aperture microphone array. The impact of different meteorological conditions on the beamforming and deconvoluted results are presented. For increasing turbulence strength, the results show decreasing sound levels and increasingly blurred images. The proposed method allows us to reproduce the effects of turbulence-induced coherence loss in phased microphone array measurements and to optimize array designs and algorithms in a virtual, controllable environment.

Item URL in elib:https://elib.dlr.de/194540/
Document Type:Article
Title:Synthesizing coherence loss by atmospheric turbulence in virtual microphone array signals
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Lincke, DorotheaUNSPECIFIEDhttps://orcid.org/0000-0002-3805-1781UNSPECIFIED
Schumacher, TimoUNSPECIFIEDhttps://orcid.org/0000-0001-8349-2570134154288
Pieren, RetoUNSPECIFIEDhttps://orcid.org/0000-0001-5280-2230UNSPECIFIED
Date:January 2023
Journal or Publication Title:Journal of the Acoustical Society of America
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:pp. 456-466
Publisher:Acoustical Society of America
Keywords:Acoustics, Flyover, Auralization, Coherence Loss, Microphone Array, Beamforming
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Clean Propulsion
DLR - Research area:Aeronautics
DLR - Program:L CP - Clean Propulsion
DLR - Research theme (Project):L - Future Engines and Engine Integration
Location: Berlin-Charlottenburg
Institutes and Institutions:Institute of Propulsion Technology > Engine Acoustic
Deposited By: Schumacher, Timo
Deposited On:02 May 2023 10:13
Last Modified:02 May 2023 10:13

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