Abstract : This paper presents a methodology to account for some mean-flow effects on thermo-acoustic instabilities when using the zero-Mach-number assumption. It is shown that when a computational domain is represented under the M=0 assumption, a nonzero-Mach-number element can simply be taken into account by imposing a proper acoustic impedance at the boundaries so as to mimic the mean flow effects in the outer, not computed flow domain. A model that accounts for the coupling between acoustic and entropy waves is presented. It relies on a "delayed entropy coupled boundary condition" (DECBC) for the Helmholtz equation satisfied by the acoustic pressure. The model proves able to capture low-frequency entropic modes even without mean-flow terms in the fluctuating pressure equation.
https://hal.archives-ouvertes.fr/hal-00905802
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Soumis le : lundi 18 novembre 2013 - 16:44:52
Dernière modification le : jeudi 13 septembre 2018 - 14:20:03
Document(s) archivé(s) le : mercredi 19 février 2014 - 12:15:12
Emmanuel Motheau, Laurent Selle, Franck Nicoud. Accounting for convective effects in zero-Mach-number thermoacoustic models. Journal of Sound and Vibration, Elsevier, 2014, vol. 333, pp. 246-262. 〈10.1016/j.jsv.2013.08.046〉. 〈hal-00905802〉
