Slow rupture of viscous film: theory and experiment

A rupture of viscous levitating horizontal film between parallel needles is considered. The system reaches remarkable steady-state propagation mode. Profile of the rupture is similar to U-shape. Visually, the system resembles many classical problems such as rising long bubble in the tube, or Hele-Shaw tongue. The system has a clear separation of scales: the rim on the rupture front is substantially thicker than the film itself, but much smaller than distance between the needles. This allows to develop a simple theory of the rupture propagation. The theory agrees well with the experiments.