Numerical simulation of underwater air bubble formation under rolling conditions

Underwater gas bubbles are universal phenomenon in various industries. These bubbles appear under ocean conditions especially rolling conditions, that affect the mass transfer and produce different acoustic signals. The bubble formation and oscillation frequency characteristics under rolling conditions were investigated in this study by using a numerical method. Results showed that the bubbles followed two basic steps under rolling conditions, namely, expansion and detachment. The bubble detachment surface area and shape exhibited periodic changes because of the periodical motion of the surrounding water. A correlation was established to predict the bubble detachment surface area under rolling conditions. Similar to the bubble detachment surface area, the bubble oscillation frequency periodically changed. The oscillation mode of the bubbles under rolling conditions was the same as those under motionless condition, that is zeroth mode. A modified Minnaert formula was established to predict the bubble oscillation frequency under rolling conditions.