Capillary-driven two-dimensional buoyancy in vertical soap films

The present study aims to investigate the capillary-driven buoyant effects in nearly two-dimensional systems. The case of rising rings in vertical soap films is studied both experimentally and theoretically. Since the pioneering works of Mysels and coworkers, the thickness differences and related two- dimensional densities are considered as the motor leading to two- dimensional buoyancy. We show how this effect can be re- interpreted in terms of the surface tension profiles present at the film interfaces. We propose a model involving surface tension profiles, as well as an adapted expression for the mass of the rising rings, and compare it to experimental data. Copyright (C) EPLA, 2014