高速射弹小角度入水弹道特性分析

Analysis of Trajectory Characteristics of Water-Entry of the High-Speed Projectile at Small Angel

摘要:

为了研究高速射弹小角度入水空泡发展与弹道特性，开展了入水角度为20°时的高速入水试验研究。高速射弹由空气炮加速获得入水初速，利用高速摄像实现对入水空泡形态的记录，由内测单元记录射弹入水过程的运动参数。试验发现，入水初期形成了光滑透明的空泡，射弹以超空泡状态近直线弹道运动;由于横滚角速度和俯仰角速度的存在，射弹入水后形成了尾拍+旋转滑水耦合运动特征；基于VOF多相流模型和空化模型，结合动网格技术，对试验工况进行数值仿真。结果表明：仿真获得的空泡形态、弹道特性与试验结果吻合度高，该方法可有效预报入水弹道。

Abstract:

In order to study the trajectory characteristics of water-entry of the high-speed projectile at small angle, the experimental study is carried out when the water angle is 20°. An air cannon is set up to provide the initial velocity of high-speed projectile, the flow pattern in water-entry is captured by using a high-speed video camera, and the variations of the parameters are recorded by using a built-in measuring system. The experiment result show that the smooth and transparent vacuoles are formed at the initial stage of water-entry, the projectile moves in a liner trajectory in a supercavitation state. When entering the water, due to existence of roll angular velocity and oitch angular velocity, the projectile forms the motion characteristics of tail beat + spin water skiing coupling. Based on the VOF multiphase flow model and cavitation model, combined with the dynamic grid technology, the numerical simulation of the experimental conditions was carried out. The results indicate that the cavitation shape and trajectory characteristics obtained by simulation are in good agreement with the experiment result, it can effectively predict the water-entry trajectory.