A NUMERICAL STUDY OF THE BREAKING OF AN INTERNAL SOLITON AND ITS INTERACTION WITH A SLOPE

The full Navier-Stokes and diffusion equations are applied to study th e breaking of an internal soliton on the continuously stratified pycno cline in a two-layer system and its interaction with a slope. First, t hese equations are solved numerically to study the limiting height and breaking of the soliton in the case of constant total depth. Breaking occurs when the particle velocity in a region of flow field exceeds t he wave celerity. This results in a gravitational instability with a p atch of dense water entraining into the upper layer in the lee of the wave. The numerically determined breaking criterion is supported by an estimate using the first-order Korteweg-de Vries (KdV) theory. Then, the model is used to examine the interaction of the soliton with a slo pe-shelf topography and a uniform slope. In both cases, the relative d epths of the layers change at the turning point along the slope. Mecha nisms of the wave breaking and wave propagation processes for both cas es are described. Scaled bottom stresses and total wave run-up on the slope are also presented.