Dynamique de bulles traversant l'interface séparant deux liquides

Abstract

We investigate experimentally and computationally the passage of air bubbles through an initially flat horizontal interface separating two Newtonian liquids. We use various liquids in such a way that their viscosity ratio can vary by more than two orders of magnitude; the density contrast and the interfacial tension also vary to a certain extent. Two different injection systems are used and allow us to generate bubbles with diameters ranging typically from 1 mm to 2 cm, the biggest bubbles being toroidal. In parallel we carry out axisymmetric computations based on two distinct approaches, namely an interface capturing technique (a VOF approach without interface reconstruction) and a Cahn-Hilliard model coupled with the Navier-Stokes equations. © AFM, EDP Sciences 2011.