Dynamics of the rapid creation and collapse of dry spot regions int fluid layers*

When the free surface of a fluid under gravity creates a dry spot by intersecting a confining bottom boundary, the evolution of the fluid system and the subsequent collapse of the dry spot pose many fundamental questions, from both mathematical and physical viewpoints. Models of the dynamics of this phenomenon can be valuable in isolating relevant mechanisms governing the collapse. This talk will present results from applying such simplified models to the above setup, and show their effectiveness, and limitations, by comparing model predictions with results from both direct numerical simulations and data from experiments of dry spot collapse. In particular, we present a novel way to overcome the experimental challenge of creating a dry-spot cavity without generating significant initial velocity in the bulk of the fluid.