Experimental Investigations on the Interplay between a thermoacoustic oscillator and an external acoustic driver with different waveforms

Abstract

Recent studies have reported on the various nonlinear behaviors (e.g., synchronization) resulting from the mutual interaction between a thermoacoustic oscillator and an external acoustic driver producing sinusoidal waves. This work extends previous research by experimentally investigating the dynamic behavior of a thermoacoustic oscillator subjected to external disturbances with different waveforms including triangular and irregular waves. The experimental data are analyzed using various signal processing techniques such as Fast Fourier Transform, wavelet transform, and phase space trajectories. Results reveal that apart from sinusoidal waves, both triangular and irregular waves can be utilized to synchronize the thermoacoustic oscillator. When synchronization occurs, the oscillator will transit from initial periodic oscillations at the natural frequency to final periodic oscillations at the driving frequency. The acoustic pressure resembles the external disturbance at the open end (e.g., triangular waves) but shifts towards sinusoidal waves when approaching the closed end. It is found that synchronization can happen if the dominant frequency of the external disturbance closely aligns with the natural frequency of the oscillator, even in the presence of harmonic components. This study provides an experimental framework for investigating the dynamic behavior of thermoacoustic oscillators under external disturbances, enhancing our understanding of synchronization phenomena in thermoacoustic devices.