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On the Contribution of Higher Azimuthal Modes to the Near- and Far-Field of Jet Mixing Noise

Neifeld, A. und Ewert, R. (2012) On the Contribution of Higher Azimuthal Modes to the Near- and Far-Field of Jet Mixing Noise. 18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference), 2012-06-04 - 2012-06-06, Colorado Springs, CO, USA.

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Offizielle URL: http://www.aiaa.org

Kurzfassung

The prediction of jet mixing noise is studied using a stochastic realization of the Tam & Auriault source model. The acoustical sources are generated by means of the Random Particle-Mesh Method (RPM), which utilizes turbulence statistics as provided by solu- tions to the Reynolds Averaged Navier-Stokes (RANS) equations. The generated stochas- tic sound sources closely realize the two-point cross-correlation function used in the jet noise model to prescribe the fine-scale sound source. The RPM code is coupled with the DLR CAA solver PIANO. The azimuthal-modal decomposed linearized Euler equations are applied as governing equations. With this approach, it is possible to evaluate jet noise spectra at any position in the near-field. Based on an azimuthal decomposition, 3-D sound radiation from the jet can be reproduced at the computational price of a few axisymmetric 2-D computations. Furthermore, it will be shown, that we are able to verify the imple- mented methodology with the results published for the genuine model. The spectra are correctly predicted in terms of sound pressure levels, Mach scaling exponent and spectral shape. A Strouhal number range of up to St = 10 can be covered using the first six az- imuthal mode components of the broadband source. To reach higher Strouhal numbers more azimuthal modes have to be adopted. The presented results reveal the importance of individual azimuthal contributions to the total spectra. To evaluate the spectra in the far-field, the generated near-field noise is extrapolated with a modal Ffowcs-Williams & Hawkings (FWH) method. For the static single stream jet (Ma = 0.9) two different kinds of extrapolation were used - a simplified extrapolation and the modal FWH method. With this computational case, it was possible to predict a jet noise spectrum in the range of St = 0.01 . . . 20. To investigate the effect of different nozzle configurations on sound gener- ation, different nozzle configurations, i.e. dual-stream nozzles with and without nozzle lip treatments are simulated. Good agreement with experimental data for the noise reduction potential of nozzle lip treatments is found.

elib-URL des Eintrags:https://elib.dlr.de/76046/
Dokumentart:Konferenzbeitrag (Vortrag, Paper)
Titel:On the Contribution of Higher Azimuthal Modes to the Near- and Far-Field of Jet Mixing Noise
Autoren:
AutorenInstitution oder E-Mail-AdresseAutoren-ORCID-iDORCID Put Code
Neifeld, A.andrej.neifeld (at) dlr.deNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Ewert, R.roland.ewert (at) dlr.deNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Datum:4 Juni 2012
Open Access:Ja
Gold Open Access:Nein
In SCOPUS:Nein
In ISI Web of Science:Nein
Name der Reihe:Conference Proceedings online
Status:veröffentlicht
Stichwörter:jet noise, sound source modeling, azimuthal modes, far-field extrapolation
Veranstaltungstitel:18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference)
Veranstaltungsort:Colorado Springs, CO, USA
Veranstaltungsart:internationale Konferenz
Veranstaltungsbeginn:4 Juni 2012
Veranstaltungsende:6 Juni 2012
Veranstalter :AIAA/CEAS
HGF - Forschungsbereich:Luftfahrt, Raumfahrt und Verkehr
HGF - Programm:Luftfahrt
HGF - Programmthema:Starrflügler (alt)
DLR - Schwerpunkt:Luftfahrt
DLR - Forschungsgebiet:L AR - Starrflüglerforschung
DLR - Teilgebiet (Projekt, Vorhaben):L - Simulation & Validierung (alt)
Standort: Braunschweig
Institute & Einrichtungen:Institut für Aerodynamik und Strömungstechnik > Technische Akustik
Hinterlegt von: Neifeld, Dr.-Ing. Andrej
Hinterlegt am:09 Aug 2012 09:58
Letzte Änderung:24 Apr 2024 19:42

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