<p>This paper presents a numerical analysis of the flow field around projectiles with varying tip geometries entering water, with the aim of elucidating the phenomena of underwater shock waves and supercavitation in maritime science. The study combines high-speed visualization experiments and numerical simulations to investigate the underlying mechanisms. Three types of projectiles are launched into water using a high-pressure gas release system, and numerical simulations are performed using the smoothed particle hydrodynamics (SPH) method. The results demonstrate that the SPH method effectively reproduces experimental observations of water surface deformation and the flow field surrounding the projectiles. The intensity of underwater shock waves and the formation of cavities around the projectiles are shown to depend on both the impact velocity and the projectile's tip geometry. Moreover, cavity formation is identified as a critical factor in reducing fluid resistance.</p>