Wave generation through the interaction of a mode-2 internal solitary wave and a broad, isolated ridge

The passage of a mode-2 internal solitary wave (ISW) over a broad, isolated ridge was explored using both numerical simulations and laboratory experiments. At sufficient incident wave amplitude and speed, the interaction with the ridge caused a deceleration of the incident wave while also generating three wave types: leading mode-1 ISWs, a trailing mode-1 wave-packet, and a trailing mode-2 ISW. The trailing mode-2 ISW was formed as the second piece of the fissioned incident wave. While mode-mode interactions are not part of typically applied weakly nonlinear theories, the fissioning of the leading mode-2 ISW into two mode-2 waves is predicted qualitatively by weakly-nonlinear theory. However, the present study is, to our knowledge, the first experimental and numerical confirmation of the detailed evolution of this phenomenon. In contrast to the previously studied transit of a mode-2 ISW onto a shelf, the parameters quantifying the strength of each resultant wave are found to be independent, having no singular predictor existing for all waves. Lastly, cross-boundary layer transport was found to be more strongly dependent on Reynolds number than on incident wave or background conditions.