Dynamics and acoustics of bubbles detached from non-rigid orifices

The presence of natural gas hydrates often coincides with the formation of bubble plumes, serving as evidence for their existence and potential exploitation. Bubble formation boundaries are non-rigid and differ from those formed at rigid boundaries. This study employed an image and acoustic signal synchronization acquisition device in the experimental area to investigate the effects of gas flow rate on the dynamics and acoustics of bubble release from particle layers. The results indicate that as gas flow rate increases, bubble size, production frequency, and particle displacement range increase, while the primary frequency of bubble acoustics decreases. Additionally, the time domain waveform of bubble formation changes from triangular to spindle-shaped; the primary frequency of acoustic signals decreases from 1072 to 625 Hz, with a gradual concentration in distribution. Acoustic frequencies calculated using the Minnaert formula and equivalent diameter are higher than those measured by hydrophones. The initial bubble's acoustic signal intensity and duration are greater than those of subsequent bubbles. This work contributes to the advancement of natural gas hydrate detection techniques and the analysis of their distribution patterns.