Motion of a foam lamella in a circular channel under a relaxing small pressure jump

The drag force of a foam lamella moving along a circular tube under low pressure drop was measured experimentally. We applied a small pressure jump on one side of the lamella and followed its trajectory until this pressure jump is relaxed. The experimental trajectories were found to be significantly different from those resulted from theoretical model based on a viscous resistance of the Plateau border. An alternative model is suggested. The model is based on the assumption that strong deformation of surface around the Plateau border causes considerable variation of the surface tension and the variation controls the lamella motion.