关键词: 小角度入水, 超空泡射弹, 空泡, 入水稳定性

Abstract: The initial angle of attack and sideslip angle are critical parameters in the small-angle water entry process of supercavitating projectiles, significantly influencing the stability during water entry. This study established a numerical simulation model for the small-angle water entry of supercavitating projectiles based on the Schnerr-Sauer cavitation model, multiphase flow model, and overset grid technology. To verify the effectiveness of the model, high-speed small angle water entry tests were conducted using high-speed cameras and ballistic guns. The experimental results showed good agreement with the numerical simulations, confirming the reliability of the developed numerical method.Using the validated numerical model, this study systematically investigated the water entry process of supercavitating projectiles under different initial angles of attack and sideslip angles. The research focused on analyzing the characteristics of cavity evolution, flow field distribution, and the variations in projectile motion parameters (including velocity, pitch angle, angle of attack, etc.) and hydrodynamic parameters. The results indicate that a small positive angle of attack can enhance the stability of the projectile during water entry. However, beyond a certain critical value, the hydrodynamic coefficients exhibit significant fluctuations, leading to trajectory instability. In contrast, a negative angle of attack, regardless of its magnitude, reduces the stability of the projectile during water entry. An increase in the sideslip angle causes asymmetric compression of the cavity, resulting in a distinctly asymmetric cavity distribution and intensified tail-slapping phenomena, which significantly degrade the projectile's motion stability.

Key words: small angle water entry, supercavitating projectile, cavity, stability of water entry