入水空泡振荡对弹体载荷与弹道特性的影响研究OA

To investigate the cavitation oscillation phenomenon caused by the water-skimming motion of high-speed projectiles during water entry and its impact on hydrodynamic loads and ballistic characteristics,a numerical calculation method for high-speed water entry of trans-media vehicles using a fluid volume multiphase flow model and dynamic grid technology was established in this paper.The effectiveness of this method was verified through water entry experiments.Based on this,numerical simulation were conducted on the evolution stages of water entry cavitation,including generation,development,and collapse.The formation mechanism of cavitation wall fluctuations and the impact of oscillatory loads on hydrodynamic characteristics and ballistic stability were systematically analyzed.The results show that cavitation wall fluctuations occur during the"deep closure"stage of water entry cavitation,with the cavitation wall near the cylindrical section of the projectile exhibiting a"corrugated"feature,and the oscillation transmission stagnates at the cone-cylinder junction.The cavitation oscillation stage significantly affects the hydrodynamic characteristics of the projectile,with hydrodynamic coefficients exhibiting severe pulsation characteristics.However,the total force increase due to the pulsating load on the model does not exceed 10％,and the characteristic frequency of this load is concentrated below 2 000 Hz.The stable ballistic characteristics formed at the initial stage of water entry can effectively resist the complex mechanical environment caused by cavitation oscillation,ensuring good consistency between the actual water entry trajectory and the ideal trajectory.This study provides theoretical references for a deeper understanding of the cavitation oscillation mechanism during water entry,optimizing the hydrodynamic design of cross-media projectiles,and improving ballistic stability.