On the velocity of expanding spherical gas bubbles rising in line in supersaturated hydroalcoholic solutions: Application to bubble trains in carbonated beverages

We report in this paper measurements of the rising velocity of champagne bu bbles, investigated by using a camera and a stroboscopic light. It is shown that the velocity of bubbles during ascent is intermediate between that of a rigid sphere and that of a fluid sphere free from surface-active compoun ds. We show that our experimental results are compatible with a model of su rfactant diffusive flux toward a moving sphere, suited to the case of risin g and expanding gas bubbles. The critical surface concentration of contamin ants needed to completely rigidify the bubble interface may not be reached in real conditions, i.e., in a flute. The rising velocity of champagne bubb les is then compared with the velocity of bubbles in beer. Contrary to cham pagne bubbles, beer bubbles are found to behave hydrodynamically as rigid s pheres.