Dripping of a suspended thin viscous film

Thin viscous films are ubiquitous in nature and industry, such as bubble draining, polymer processing and glass manufacturing. In this report, we investigate, both experimentally and numerically, the sagging and dripping of a thin viscous film due to gravity, which is suspended in air and hinged at the rim. Initially the bending forces dominate in the film; for intermediate times, the stretching forces become more significant as the deformation of the film increases; at late times a “blob” forms at the center of the film due to thickening and detaches from the film. Then, the film recovers the intermediate-time behavior and starts another cycle until it breaks up due to the loss of mass from dripping at the center. Our model incorporates both gravity and surface tension effects and the numerical results are in good agreement with the experiments.