Cylindrical versus spherical self-similar capillary cavity collapse

Drop tower experiments have been performed to study the capillary collapse of large high-aspect-ratio cavities. Cavities are formed by momentarily impinging the free surface of a liquid bath with a jet of air in the microgravity environment of a drop tower. The collapse may give rise to a jet and three distinct jetting regimes are identified. Simulations are performed to further investigate the phenomena. The abrupt emergence of a thin high velocity jet is observed experimentally and numerically at a specific initial cavity aspect ratio. Different power laws are identified in different regions of the cavity during the collapse providing further understanding of cavity collapse phenomena. In particular, it shows that the spherical and cylindrical self-similar collapses can compete simultaneously, that is, during the same collapse, for determining the final thin jet formation.