Bubble Cutting by Cylinder – Elimination of Wettability Effects by a Separating Liquid Film

Experiments and simulations are presented for the interaction of single bubbles rising in a viscous liquid against a horizontal cylinder (Ø = 4 mm) of varying wettability. The slide-off of small and the cutting of larger bubbles into two daughter bubbles observed in the experiment are reproduced by phase-field simulations. It is shown that in the entire process bubble and cylinder are separated by a liquid film, which eliminates any influence of cylinder wettability. Before the mother bubble splits, a thinning gas thread develops below the cylinder. The rupture of this gas thread can lead to a different number of satellite bubbles depending on the conditions.