Mechanism analysis of internal solitary waves breaking encountering submarine ridges based on laboratory experiments

Internal solitary waves are commonly present in global oceans, and these waves encounter submarine ridges during their propagation, resulting in breaking. In this study, a two-layer fluid model and the gravity collapsing method were used to simulate the breaking process of internal solitary waves encountering submarine ridges in the laboratory, and particle image velocimetry was used to monitor the flow field. Based on the different roles of motion mechanisms in the wave-breaking process, the breaking types were classified. Moreover, the relationship between the topography, the initial parameters of internal solitary waves, and the breaking types was studied, and the movement parameters during the wave-breaking process were analyzed. The experiments showed that the Iribarren number and Bisw parameter proposed based on the gentle slope breaking process could not effectively classify the breaking types when internal solitary waves encountered submarine ridges because the permeability of the submarine ridges was different from that of gentle slopes, which significantly affected the motion mechanism during the breaking process. The movement parameter γ clearly reflected the roles of different motion mechanisms during the wave-breaking process. Another parameter δ established the relationship between the motion mechanisms and the topography and initial wave parameters.