Axisymmetric cavity collapse in parametrically forced gravity waves at varying liquid depth

Experiments are carried out in a circular cylinder (2R=10cm) for: deep, intermediate and shallow conditions to compare the jetting behavior. The presence of bottom wall increases the dissipation that dampens the disturbances. In the breaking regime, cavity formed by the large amplitude wave results in intense jet from free surface demonstrated by previous researchers in deep water. A critical fluid depth is identified in intermediate depth up to which the collapse exhibits similar behavior. Beyond this depth the cavity aspect ratio (depth to radius) and implosion is strongly affected by the bottom wall, resulting in reduced jet velocity. A power law dependence of radial length scale of the cavity with time remaining for collapse has been observed. Power law exponent at initial stage is found to be ½, which crosses over to 1 in the later stages indicating an inertial-viscous crossover. At intermediate depth, when the cavity touches the bottom wall such a transition is not well identified. At very shallow depth, eventually very small aspect ratio, leads to multiple transition like viscous-inertia-viscous to approach the collapse that is similar to a pinch-off of liquid bridges in highly viscous medium. With available resolution a viscous-inertial transition is captured.