Research on Water-Entry Hydrodynamics for a Cross-Wing Underwater Vehicle

The optimization of the water-entry strategy for cross-wing underwater vehicles has become a research hotspot in the field of engineering, and its water-entry process is quite different from that of wedges and cylinders. In order to address this problem, a water-entry numerical model for the cross-wing underwater vehicle was first established based on the CFD method. The governing equations and boundary conditions of the dynamic model were defined, along with the basic principles of discretization and turbulent flow of the governing equations. The overset mesh and the VOF multiphase flow model were introduced, and a mesh size independence analysis of the numerical model was conducted. Furthermore, the numerical results were compared with the experimental results to ensure the accuracy of the numerical model. The research focused on the cross-wing underwater vehicle’s impact with calm water and regular waves, respectively. The results show that: (1) the numerical simulations are in good agreement with the experimental results (the maximum predictive error is less than 10%), which verifies the accuracy of the numerical model in this paper; (2) when the cross-wing underwater vehicle impacts calm water, the slamming pressure curve firstly shows a trend of increasing, reaching a peak, and then decreasing sharply, and finally stabilizes. As the water-entry velocity increases, the peak slamming pressure exhibits a gradual increase; (3) during the water entry of the cross-wing underwater vehicle into calm water, the acceleration profile demonstrates a trend of initial increase, followed by a decrease, another increase, and then a subsequent decrease as the entry velocity continues to rise. It should be noted that there are two peaks in the acceleration, with the first peak being significantly smaller than that of the second; (4) when the cross-wing underwater vehicle impacts a regular wave, the slamming pressure is lowest when impacting the crest and highest when impacting the trough.