Experimental study of the growth period of wall-attached bubbles

Abstract

Abstract Due to dam discharge, waterfalls, sudden increases in water temperature and oxygen production by photosynthesis, the total dissolved gas (TDG) in water is often supersaturated, which may have serious effects on aquatic ecology. Wall-attached bubbles formed during the TDG release process and the generation and departure of wall-attached bubbles influenced the release of TDG from water. Therefore, an experiment was performed to simulate the growth of wall-attached bubbles at various water flow velocities, a quantitative relationship between the wall-attached bubble growth period and flow velocity was obtained. Another quantitative relationship, between the wall-attached bubble departure diameter and turbulent kinetic energy of flowing water, was also determined. The analysis results of the TDG release rate proved that the adsorption of TDG on solid walls was considerably affected by flow velocity. The analysis models the TDG release mechanism through complex experiments and provides a method to better identify sites for supersaturated TDG adsorption. This study serves as an important theoretical basis for revealing the mechanism by which solid surfaces promote the release process of supersaturated TDG in natural water.