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 bubbles, 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 compounds. We show that our experimental results are compatible with a model of surfactant diffusive flux toward a moving sphere, suited to the case of rising and expanding gas bubbles. The critical surface concentration of contaminants needed to completely rigidify the bubble interface may not be reached in real conditions, i.e., in a flute. The rising velocity of champagne bubbles is then compared with the velocity of bubbles in beer. Contrary to champagne bubbles, beer bubbles are found to behave hydrodynamically as rigid spheres.