Numerical investigation on motion response and load characteristics of interaction between internal solitary wave and multi-unmanned underwater vehicles

Internal Solitary Waves (ISWs) pose the significant threat to the operational safety of multiple Unmanned Underwater Vehicles (multi-UUVs) due to the immense energy they carry. In this paper, the motion response and load characteristics of multi-UUVs encountering ISW in an immiscible two-layer fluid system are investigated. Three key parameters, including wave amplitude, relative distance, and advancing speed, have been considered to analyze their effect on the hydrodynamic performance. The results show that as the wave amplitude rises, the relative motion trajectory changes from water drop to triangle. In the lower layer of the fluid, both horizontal and vertical forces increase with advancing speed. In addition, the dangerous diving depth parameter is defined, and empirical formations are derived for the velocity and control time in the suspended state of the multi-UUVs and the vertical velocity in the self-propelled state, respectively.