Structural Optimization and Stability Analysis for Supercavitating Projectiles

Stability is the key issue for kinetic-energy supercavitating projectiles. Our previous work established a six degrees of freedom (DOF) dynamic model for supercavitating projectiles. However, the projectile’s structure did not meet our current design specifications (its sailing distance could reach 100 m at an initial speed of 500 m/s). The emphasis of this study lies in optimizing the projectile’s configuration. Therefore, a program was developed to optimize the projectile’s structure to achieve an optimal design or the largest sailing distance. The program is a working optimal method based on the genetic algorithm (GA). Additionally, the convergence standard and population producing strategy were improved, which greatly elevated the calculation speed and precision. To meet design specifications, the improved GA was combined with the 6DOF model, which establishes a dynamic optimization problem. The new projectile’s structure was obtained by solving this problem. Then, the new structures’ dynamic features were compared with the ideals proposed in this paper. The criterion of stability, which is called weakened self-stability, was redefined based on the results. The weakened self-stability is the optimal stability for an actual kinetic projectile motion, and it is instructive for the design of supercavitating projectiles in the future.