Synchronization and chimeras in a network of four ring-coupled thermoacoustic oscillators

Yu Guan, Kihun Moon, Kyu Tae Kim, Larry K.B. Li

Research output: Journal article publicationJournal articleAcademic researchpeer-review

18 Citations (Scopus)

Abstract

We take a complex systems approach to investigating experimentally the collective dynamics of a network of four self-excited thermoacoustic oscillators coupled in a ring. Using synchronization metrics, we find a wide variety of emergent multi-scale behaviour, such as (i) a transition from intermittent frequency locking on a quasiperiodic attractor to a breathing chimera, (ii) a two-cluster state of anti-phase synchronization on a periodic limit cycle, and (iii) a weak anti-phase chimera. We then compute the cross-transitivity from recurrence networks to identify the dominant direction of the coupling between the heat-release-rate and pressure fluctuations in each individual oscillator, as well as that between the pressure (and) fluctuations in each pair of coupled oscillators. We find that networks of non-identical oscillators exhibit circumferentially biased - coupling, leading to mode localization, whereas networks of identical oscillators exhibit globally symmetric - coupling. In both types of networks, we find that the - coupling can be symmetric or asymmetric, but that the asymmetry is always such that exerts a greater influence on than vice versa. Finally, we show through a cluster analysis that the - interactions play a more critical role than the - interactions in defining the collective dynamics of the system. As well as providing new insight into the interplay between the and coupling, this study shows that even a small network of four ring-coupled thermoacoustic oscillators can exhibit a wide variety of collective dynamics. In particular, we present the first evidence of chimera states in a minimal network of coupled thermoacoustic oscillators, paving the way for the application of oscillation quenching strategies based on chimera control.

Original languageEnglish
Article numberA5
JournalJournal of Fluid Mechanics
Volume938
DOIs
Publication statusPublished - 10 May 2022
Externally publishedYes

Keywords

  • instability
  • Nonlinear dynamical systems
  • turbulent reacting flows

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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