JRP analysis of synchronization loss between signals recording during bubble departures

Abstract

The synchronization between the air pressure fluctuations and the depth of liquid penetration into the nozzle during bubble departures was investigated using joint recurrence quantification analysis. In the experiment, the bubbles were generated from a glass nozzle into distilled water. During the analysis, the recurrent rate coefficients were calculated for the depth of liquid penetration into the glass nozzle and pressure changes in the gas supply system. The study was conducted by two air volume flow rates, i.e. 0.023 l/min and 0.026 l/min. The air volume flow rates were selected so that the appearance and disappearance of period bubble departures were clearly visible. It has been shown that the synchronization of the pressure changes and the depth of liquid penetration appears when periodic changes in the depth of liquid penetration occur in a relatively long period of time. The process of changing the distance between the extremes of liquid penetration into the nozzle and pressure changes in the gas supply system was observed. It has been found that the decrease in the distance between these extremes is responsible for the appearance of periodic bubble departures. This behaviour has not been reported in previous papers. This process was modelled by numerical simulations.

A hydrodynamic interaction between bubbles and gas supply system during gas bubble departures in liquids: an experimental study

“…In 10 , it was shown that the chaotic character of bubble trajectories is caused by the departed bubble’s shape and liquid flow generated by the moving bubble in the bubble column. Moreover, two groups of phenomena responsible for the chaotic nature of bubble behaviours (the first group—bubble interface oscillations, liquid flow around the needle, and the second group—processes which appear in the gas supply system) are proposed 12 – 14 . It can be assumed that the liquid flow above the needle can modify the processes that appear in the needle, and consequently, the pressure fluctuation in the gas supply system.…”