Deconvolution of azimuthal mode detection measurements

Pieter Sijtsma, Harry Brouwer

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

Abstract

Unequally spaced transducer rings make it possible to extend the range of detectable azimuthal modes. The other side of the coin is that the response of the mode detection algorithm to a single mode is distributed over all detectable modes, similarly to the Point Spread Function of Conventional Beamforming with microphone arrays. With multiple modes the response patterns interfere, leading to a relatively high “noise floor” of spurious modes in the detected mode spectrum, in other words, to a low dynamic range. In this paper a deconvolution strategy is proposed for increasing this dynamic range. It starts with separating the measured sound into shaft tones and broadband noise. For broadband noise modes, a standard Non-Negative Least Squares solver appeared to be a perfect deconvolution tool. For shaft tones a Matching Pursuit approach is proposed, taking advantage of the sparsity of dominant modes. The deconvolution methods were applied to mode detection measurements in an AneCom fan rig. An increase in dynamic range of typically 10 to 15 dB was found.

Original languageEnglish
Title of host publication23rd AIAA/CEAS Aeroacoustics Conference
Subtitle of host publication5-9 June 2017, Denver, Colorado
PublisherAmerican Institute of Aeronautics and Astronautics Inc. (AIAA)
Number of pages14
ISBN (Electronic)9781624105043
DOIs
Publication statusPublished - 2017
Event23rd AIAA/CEAS Aeroacoustics Conference - Denver, United States
Duration: 5 Jun 20179 Jun 2017
Conference number: 23
https://doi.org/10.2514/MAA17

Conference

Conference23rd AIAA/CEAS Aeroacoustics Conference
CountryUnited States
CityDenver
Period5/06/179/06/17
Internet address

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