Deflection law in trajectory of large caliber conical-nosed projectile at high-speed oblique water entry.

This article systematically investigates the deflection behavior of a large-caliber conical-nosed projectile during high-speed oblique water entry through integrated high-speed experiments and numerical simulations based on the arbitrary Lagrange–Euler (ALE) fluid–structure interaction method. The study validates the simulation model against ballistic test data and analyzes the force modes, pitching moments, and cavity evolution influencing projectile trajectory under varying impact velocities, oblique angles, and attack angles. Key findings indicate that projectile instability is primarily caused by pitching moments affected by entry conditions; higher impact velocities accelerate deflection rates, oblique angles influence both deflection degree and rate with distinct behaviors below 15°, between 30°–60°, and at 75°, and attack angles significantly affect deflection direction and magnitude. The research provides insights relevant for predicting underwater ballistic trajectories and optimizing projectile design and impact conditions in underwater weapon applications.