Spontaneous and explicit symmetry breaking of thermoacoustic eigenmodes in imperfect annular geometries

Autor:	Nicolas Noiray, Thomas Indlekofer, Abel Faure Beaulieu, James Dawson
Rok vydání:	2022
Předmět:	Mechanics of Materials Reacting Flows: Combustion Acoustics: Acoustics Mechanical Engineering Applied Mathematics Nonlinear Dynamical Systems: Nonlinear Dynamical Systems Combustion Nonlinear Dynamical Systems: Nonlinear Dynamical Systems [Reacting Flows] Condensed Matter Physics
Zdroj:	Journal of Fluid Mechanics, 944
ISSN:	1469-7645 0022-1120
Popis:	This article deals with the symmetry breaking of azimuthal thermoacoustic modes in annular combustors. Using a nominally symmetric annular combustor, we present experimental evidence of a predicted spontaneous reflectional symmetry breaking, and also an unexpected explicit rotational symmetry breaking in the neighbourhood of the Hopf bifurcation which separates linearly stable azimuthal thermoacoustic modes from self-oscillating modes. We derive and solve a multidimensional Fokker-Planck equation to unravel a unified picture of the phase space topology. We demonstrate that symmetric probability density functions of the thermoacoustic state vector are elusive, because the effect of asymmetries, even imperceptible ones, is magnified close to the bifurcation. This conclusion implies that the thermoacoustic oscillations of azimuthal modes in real combustors will systematically exhibit a statistically dominant orientation of the mode in the vicinity of the Hopf bifurcation. Journal of Fluid Mechanics, 944 ISSN:0022-1120 ISSN:1469-7645
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7ce29500dd0229e0145c0ebdafedd972 https://doi.org/10.1017/jfm.2022.468 Zobrazit plný text záznamu