Multi-Medium ALE Algorithm-Based Simulation of Vertical and High-Speed Water Entry of Cylinder

Aiming at the problem of high-speed water entry load of large-caliber flat-head revolving body launched by offshore platform in the future, the validity of the multi-medium arbitrary Lagrange-Euler(ALE) algorithm for calculating such problems is verified via water entry load and cavity in order to investigate the dynamic response of the round chamfer of cylinder head to the vertical water entry of the cylinder, so as to make the shape design of flat-headed cylinder with the round chamfer meet the requirement for high-speed water entry strength. The vertical water entry process of the cylinders with different chamfers at a velocity of 300 m/s is numerically simulated, and the dynamic responses under the impact of water entry are obtained. By analyzing the velocity and acceleration of the cylinder in water entry, conclusions are drawn as follows: 1) In the initial stage of water entry, with the increase of the cylinder head chamfer, the attenuation of velocity becomes smaller; 2) The impact acceleration of the cylinder oscillates as it enters water; 3) The round chamfer of a certain size can effectively reduce the impact acceleration of the cylinder when it enters the water, and the peak value of impact acceleration of spherical-headed cylinder entering water is less than one tenth of that of flat-headed cylinder; and 4) The peak load of a flat-headed cylinder in vertical water entry process is linearly and positively correlated with the area of its head dome. This study may provide reference for the research on the impact process of cylindrical structure and the design of high-speed body.