Abstract
In this study, back light imaging measurements were performed for estimating bubble size distributions and simultaneous bubble velocity for electolytically-generated bubbles. We find that the bubble sizes are well approximated by a log-normal distribution with empirical parameters uniquely determined by the current density of electrolysis, and the motions of bubbles formed at high number density become unstable owing to a so-called clustering effect. The statistical analyses for the measured bubble and fluid velocities provide novel empirical models of the rise velocity and drag force for clustered micro-bubbles, which may be applicable to bubbly flows under breaking waves.
