Weitere Artikel dieser Ausgabe durch Wischen aufrufen
The online version of this article (doi:10.1007/s00348-013-1531-5) contains supplementary material, which is available to authorized users.
This work was first presented in condensed form at the 16th Int Symp on Applications of Laser Techniques to Fluid Mechanics in Lisbon, Portugal, 09–12 July, 2012.
This article is part of the Topical Collection on Application of Laser Techniques to Fluid Mechanics 2012.
Time-resolved particle image velocimetry (TR-PIV) has become a valuable tool for spatio-temporally resolved flow measurements. Current camera and laser technology has advanced such that time-domain events leading to sound generation can now be resolved over a reasonable spatial extent. This paper reports on the application of TR-PIV for the analysis of aeroacoustic sources in a free jet using the direct correlation between in-flow velocity fluctuations on the jet center-line and near-field pressure fluctuations. This correlation is considered both in the time domain and in the frequency domain (coherence), and the effect of TR-PIV errors on these estimates is considered by comparison to hot-wire anemometer measurements. In addition, a recently developed wavelet filtering technique is used to separate the acoustic and hydrodynamic components of recorded near-field pressure signals, enabling a gain in the signal-to-noise ratio. The results show that TR-PIV can recover the same time-domain correlation available from hot-wire and traditional PIV measurements, but that the frequency-domain estimates are corrupted by error, particularly at high frequencies. This result negates the principal benefit of using TR-PIV over PIV (the availability of coherence estimates). Despite this result, an analysis of the correlation signature gives evidence that large-scale, convecting, wave-like structures are associated with sound production, a result consistent with observations by many recent investigators. The analysis shows that in the presence of such large-scale structures, noise source localization based on the traditional correlation technique is ambiguous.
Bitte loggen Sie sich ein, um Zugang zu diesem Inhalt zu erhalten
Sie möchten Zugang zu diesem Inhalt erhalten? Dann informieren Sie sich jetzt über unsere Produkte:
TXT (4.12 KB)348_2013_1531_MOESM1_ESM.txt
Bridges J, Wernet M (2007) Effect of temperature on jet velocity spectra. Technical Memorandum NASA/TM—2007-214993; AIAA-2007-3628, NASA Glenn Research Center, Cleveland, Ohio
Henning A, Ehrenfried K (2008) On the accuracy of one-point and two-point statistics measured via high-speed PIV. In: Proceedings of the 14th international symposium on the application of laser techniques to fluid mechanics. Lisbon, Portugal
Henning A, Koop L, Ehrenfried K (2010a) Causality correlation in aeroacoustic experiments by means of simultaneous PIV and microphone-array. In: Proceedings of the 3rd Berlin beamforming conference. Berlin, Germany
Henning A, Schröder A, Krebs I, Agocs J (2010b) Aeroacoustic investigations on a cold jet by means of simultaneous PIV and microphone measurements. In: Proceedings of the 15th international symposium on applications of laser techniques to fluid mechanics
Kennedy J (2010) The influence of chevrons on the turbulent characteristics of jets. PhD thesis, University of Dublin, Trinity College
Kennedy J, Fitzpatrick J (2010) The effect of chevrons on the turbulence characteristics of jets. In: Proceedings of the 16th AIAA/CEAS aeroacoustics conference. Stockholm, Sweden
Kerhervé F, Fitzpatrick J (2010) Measurement and analysis of the turbulent length scales in jet flows. Exp Fluids. doi: 10.1007/s00348-010-0957-2
Panda J (2005) Identification of noise sources in high speed jets via correlation measurements: a review. Contractor Rep. CR-2005-213817, NASA Glenn Research Center, Cleveland, Ohio
Rackl R (1973) Two causality correlation techniques applied to jet noise. PhD thesis, University of British Columbia, Vancouver, BC
Raffel M, Willert C, Wereley S, Kompenhans J (2007) Particle image velocimetry: a practical guide, 2nd edn. Springer, Berlin, Germany
Richarz WG (1978) Direct correlation of noise and flow of a jet using laser doppler. UTIAS report 230, University of Toronto Institute for Aerospace Studies, Toronto
Schröder A, Dierksheide U, Wolf J, Herr M, Kompenhans J (2004) Investigation on trailing-edge noise sources by means of high-speed PIV. In: Proceedings of the 12th international symposium on the application of laser techniques to fluid mechanics. Lisbon, Portugal
Torrence C, Compo GP (1998) A practical guide to wavelet analysis. Bull Am Meteorol Soc 79(1):6178. doi: 10.1175/1520-0477(1998)079<0061:APGTWA>2.0.CO;2
Violato D, Scarano F (2011) Three-dimensional evolution of flow structures in transitional circular and chevron jets. Phys Fluids 23(12):124,104–124,104–125. doi: 10.1063/1.3665141
Willert C, Gharib M (1991) Digital particle image velocimetry. Exp Fluids 10. doi: 10.1007/BF00190388
- Aeroacoustic source analysis using time-resolved PIV in a free jet
David E. S. Breakey
John A. Fitzpatrick
in-adhesives, MKVS, Zühlke/© Zühlke