A Serendipitous Application of Supercavitation Theory to the Water-Running Basilisk Lizard

The classic study of the water entry of a body has applications ranging from hydroballistics to behavior of basilisk lizards. The availability of Russian supercavitation theory in recent years has allowed for an even greater understanding, and was used to develop a model to predict the dynamic size, shape, and pressure of a naturally or artificially produced underwater cavity. This model combines supercavitation theory, rigid body dynamics, and hydrodynamic theory into a comprehensive model capable of determining the motional behavior of underwater objects. This model was used as the basis for modeling the vertical water entry of solid objects into a free water surface. Results from simulation of water entry of various-sized thin disks compared favorably with published experimental data from the technical literature. Additional simulated data support a disk radius dependence on a relative object depth at cavity closure that was not previously recognized. Cavity closure times are also presented.