Research on characterization of solid -liquid separation of cylindrical water entry based on the ALE method

The separation of the solid-liquid interface and the morphological evolution of the free surface during cyl inder water entry are closely correlated with surface roughness. Based on the Arbitrary Lagrangian-Eulerian (ALE) method, which accounts for the friction characteristics of rough surfaces, this paper establishes finite element models for the vertical and oblique water entry of rough cylinders. The separation position and the characterise tics of the free surface morphology are investigated. The validity of this numerical method is verified by comparing the simulation results with experimental data. Furthermore, the study focuses on analyzing the effects of varying surface roughness and entry velocities on the impact response and flow separation characteristics of the cylinder. The results show that the free liquid surface change of the cylinder water entry process simulated by the ALE method is in good agreement with the test, and the upward velocity of the solid-liquid-gas three-phase contact line of the cylinder water entry on the rough surface is lower than that on the smooth surface, so that the liquid surface is easier to be separated from the surface of the cylinder; as the roughness decreases, the separation angle exhibits a trend of initially increasing, then decreasing, and finally increasing again; as the water entry velocity increases, the separation angle of the cylinder consistently decreases.