Revisiting Taylor-Culick retractions

A freely suspended liquid film, upon rupture, spontaneously retracts under the action of surface tension. If the film is surrounded by a passive medium, the retraction velocity of the film is known to approach the classical Taylor-Culick velocity, which is independent of the viscosity of the film. However, if the external medium is viscous, the dissipation within that medium can play a role in determining the magnitude of the retraction velocity. In the present work, we experimentally study the retraction of a liquid (water) film sandwiched between air and another viscous liquid (oil). The measured retraction velocity is found to have a weaker dependence on the viscosity of the oil phase as compared to the configuration where the water film is completely covered by oil. We reveal an unprecedented regime in the We-Oh (or Ca-Oh) phase space for retracting liquid films, governed by the localized viscous dissipation in the vicinity of the three phase contact line. Furthermore, the retraction velocity was found to depend only on the viscosity of the surrounding medium and not on that of the film itself.