Coupling of three combustion oscillators with large amplitudes

We investigate synchronization phenomena in systems of two and three coupled combustion oscillators. An alcohol lamp is employed as a combustion oscillator to realize stable limit-cycle oscillations with large amplitudes, i.e., far from a Hopf bifurcation point. The time evolution of the flame brightness is measured experimentally using a photodiode, and the phase of each oscillator is extracted from the recorded time series to identify synchronization modes. In the two-oscillator system, stable in-phase synchronization is observed at short flame-to-flame distances, whereas anti-phase synchronization becomes stable as the distance increases. In the three-oscillator system, in-phase, partial-in-phase, and tri-phase synchronization modes emerge with increasing flame-to-flame distances. Based on these experimental observations, we discuss the underlying interaction mechanisms between the oscillators within the framework of a phase model.