Numerical study on trenching performances of the underwater jet flow for submarine cable laying

Submarine cables are becoming a primary solution for transmitting electricity between the mainland and the islands. Underwater trenching using the jet flow is widely employed in cable laying engineering. The numerical studies on underwater trenching performance can provide valuable information to practical engineering for enhancing operational efficiency and reducing construction costs. In this study, a numerical model based on the commercial computational fluid dynamics software Flow3D® was established and validated by corresponding experimental data. It was found that the jet flow velocity significantly influences the trench width and depth and has minor effects on the ramp slope. An increase in the trench width can be observed as the jet-flow velocity increases. The variation in the trench depth depends on the back siltation caused by the variation of the jet-flow velocity. In addition, the nozzle motion also affects the trench width and depth, decreasing as the translation velocity of the jet nozzle increases.