Mondal S, Pawar S A, Sujith R I
Indian Institute of Technology Madras, Chennai 600036, India.
Chaos. 2017 Oct;27(10):103119. doi: 10.1063/1.4991744.
Thermoacoustic instability, caused by a positive feedback between the unsteady heat release and the acoustic field in a combustor, is a major challenge faced in most practical combustors such as those used in rockets and gas turbines. We employ the synchronization theory for understanding the coupling between the unsteady heat release and the acoustic field of a thermoacoustic system. Interactions between coupled subsystems exhibiting different collective dynamics such as periodic, quasiperiodic, and chaotic oscillations are addressed. Even though synchronization studies have focused on different dynamical states separately, synchronous behaviour of two coupled systems exhibiting a quasiperiodic route to chaos has not been studied. In this study, we report the first experimental observation of different synchronous behaviours between two subsystems of a thermoacoustic system exhibiting such a transition as reported in Kabiraj et al. [Chaos 22, 023129 (2012)]. A rich variety of synchronous behaviours such as phase locking, intermittent phase locking, and phase drifting are observed as the dynamics of such subsystem change. The observed synchronization behaviour is further characterized using phase locking value, correlation coefficient, and relative mean frequency. These measures clearly reveal the boundaries between different states of synchronization.
热声不稳定性是由燃烧室中不稳定热释放与声场之间的正反馈引起的，是大多数实际燃烧器（如火箭和燃气轮机中使用的燃烧器）面临的主要挑战。我们采用同步理论来理解热声系统中不稳定热释放与声场之间的耦合。研究了表现出不同集体动力学（如周期、准周期和混沌振荡）的耦合子系统之间的相互作用。尽管同步研究分别关注不同的动力学状态，但尚未研究表现出准周期通向混沌路径的两个耦合系统的同步行为。在本研究中，我们首次通过实验观察到热声系统两个子系统之间不同的同步行为，该系统表现出如Kabiraj等人[《混沌》22, 023129 (2012)]所报道的这种转变。随着此类子系统动力学的变化，观察到了丰富多样的同步行为，如锁相、间歇锁相和相位漂移。使用锁相值、相关系数和相对平均频率进一步表征观察到的同步行为。这些度量清楚地揭示了不同同步状态之间的界限。
