Reduction of high-speed water entry load for slender projectiles by using linear buffers

This research examines the influence of a linear buffer on the impact load experienced during the high-speed water entry of slender projectiles, employing both experimental and numerical simulation methods. Experiments were carried out using a custom-designed high-speed water entry testing platform. In this setup, projectiles were propelled by an air gun, and their water entry dynamics were recorded with a high-speed camera. The results show that implementing a linear buffer significantly reduces the impact load during water entry. Compared with the prototype projectile, the impact load of the projectile equipped with a buffer can be decreased by up to 91.34%. The investigation further determined that buffer stiffness and the mass ratio between the projectile's body and head play crucial roles in determining the impact load. Within the effective range of buffer stiffness, lower values, and mass ratios are associated with enhanced load reduction. As the velocity of water entry increases, the effect of buffer stiffness on peak impact load weakens, while the influence of mass ratio becomes more prominent. These findings have important engineering implications for designing high-speed water entry systems, providing a viable strategy for reducing impact loads and improving safety and reliability.