Dynamic response of the self-propelled underwater vehicle interacting with internal solitary waves

Internal solitary waves (ISWs) generate unsteady loads that pose significant risks to the safety of underwater vehicles. In this study, a numerical model for simulating the interaction between ISWs and an underwater vehicle is established based on the N–S equation combined with the shear stress transport k−ω turbulence model and initialization wave-making. By numerical simulation, the relationship between ISWs-vehicle of initial velocity and recovery stiffness, the planar trajectories and load characteristics of underwater vehicles encountering ISWs are investigated. The results show that at lower initial velocities, the underwater vehicle's trajectory is primarily waveform; as the initial velocity increases, it transitions to fluttering and finally to a diving trajectory. For a higher initial velocity condition, the lift loss of the vehicle with Δh*=0.05 is 2.98 times larger than that with Δh*=0.2. As dimensionless initial velocity u0*>1.47, the vehicle is in danger of “falling deep.”