Synchronization of a thermoacoustic oscillator by an external sound source
Résumé
Since the pioneering works of Christiaan Huygens about the sympathy of pendulum clocks, synchronization phenomena have been widely observed in nature and science. In this paper, we describe a simple experiment which exhibits several aspects of synchronization when making use of a ther-moacoustic oscillator driven by an external sound source. Both the synchronization region of leading order around the natural frequency f0 of the oscillator and the ones of higher order (around f0/2 and f0/3) are measured as functions of the loudspeaker voltage and frequency. We also show that increasing the coupling between the loudspeaker and the thermoacoustic oscillator gives rise under some circumstances to the death of self-sustained oscillations (quenching). Moreover, two additional set of experiments are performed : the first one aims at investigating the effect of a feedback loop for which the signal captured by the microphone is delivered to the loudspeaker through a phase-shifter; the second set of experiments aims at investigating the non-trivial interaction between the loudspeaker and the thermoacoustic oscillator when this last one acts as a relaxation oscillator (spontaneous and periodic onset/damping of self-sustained oscillations). The experiment is easy to build and highly demonstrative; it might be of interest for classroom demonstrations or physics lab dealing with nonlinear dynamics.
Domaines
Acoustique [physics.class-ph]
Origine : Fichiers produits par l'(les) auteur(s)
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