Correlations of near-And far-field acoustic data in a high-speed jet

Jacques Lewalle, Kerwin R. Low, Mark N. Glauser, Zachary P. Berger

Research output: Contribution to conferencePaper

Abstract

The cross-correlations of near- and far-field pressure in a M=0.6 cold jet are oscillatory, which implies some phaselocking. A simple model and synthetic signals show that the locking may be related to the steep attenuation with distance from the near-field sensors. In the near-field, wavelet-based nonlinear filtering separates fluctuations that are recognizable at x/D = 3 and 6 ('matched') from the others ('residue'). This decomposition yields distinct signatures in the crosscorrelations. The corresponding time lags and frequencies in the cross-correlations point to several categories of sources and their locations. The interpretation is consistent with the eddy pairing or breakdown (i.e. loss of identity) as the sources of noise for short lags, but the longer time lags require another explanation.

Original languageEnglish (US)
StatePublished - Jan 1 2011
Event7th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2011 - Ottawa, Canada
Duration: Jul 28 2011Jul 31 2011

Other

Other7th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2011
CountryCanada
CityOttawa
Period7/28/117/31/11

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Nonlinear filtering
Acoustic fields
Decomposition
Sensors

All Science Journal Classification (ASJC) codes

  • Fluid Flow and Transfer Processes

Cite this

Lewalle, J., Low, K. R., Glauser, M. N., & Berger, Z. P. (2011). Correlations of near-And far-field acoustic data in a high-speed jet. Paper presented at 7th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2011, Ottawa, Canada.
Lewalle, Jacques ; Low, Kerwin R. ; Glauser, Mark N. ; Berger, Zachary P. / Correlations of near-And far-field acoustic data in a high-speed jet. Paper presented at 7th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2011, Ottawa, Canada.
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Lewalle, J, Low, KR, Glauser, MN & Berger, ZP 2011, 'Correlations of near-And far-field acoustic data in a high-speed jet' Paper presented at 7th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2011, Ottawa, Canada, 7/28/11 - 7/31/11, .

Correlations of near-And far-field acoustic data in a high-speed jet. / Lewalle, Jacques; Low, Kerwin R.; Glauser, Mark N.; Berger, Zachary P.

2011. Paper presented at 7th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2011, Ottawa, Canada.

Research output: Contribution to conferencePaper

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AB - The cross-correlations of near- and far-field pressure in a M=0.6 cold jet are oscillatory, which implies some phaselocking. A simple model and synthetic signals show that the locking may be related to the steep attenuation with distance from the near-field sensors. In the near-field, wavelet-based nonlinear filtering separates fluctuations that are recognizable at x/D = 3 and 6 ('matched') from the others ('residue'). This decomposition yields distinct signatures in the crosscorrelations. The corresponding time lags and frequencies in the cross-correlations point to several categories of sources and their locations. The interpretation is consistent with the eddy pairing or breakdown (i.e. loss of identity) as the sources of noise for short lags, but the longer time lags require another explanation.

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Lewalle J, Low KR, Glauser MN, Berger ZP. Correlations of near-And far-field acoustic data in a high-speed jet. 2011. Paper presented at 7th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2011, Ottawa, Canada.