动能弹体跨声速斜入水弹道稳定及机理研究

The trajectory stability and damage of kinetic energy projectiles oblique water-entry at velocities from subsonic to supersonic are complicated problems and serious challenges which researchers have to be faced. The research has very important scientific significance and wide technical application. Laboratory small scale model experiment is the main method for projectile oblique water entry. In this study, by using advanced high speed digital orthogonality imaging and visualizition techniques, and rotatable light-gas gun system and water tanks, the characterizations of trajectory stability and damage of projectiles launched from air to water will be performed experimentally with four different nosed-shapes, four kinds of L/D ratios, initial entry attitude, at a range of velocities from 500m/s to 2000 m/s, in oblique incident angles from 0-75 degree. The pressures and velocities field history around oblique water entry projectile are obtained by using pressure transducers and high-speed particle image velocimetry system (PIV). The projectile three dimensional flight attitude trajectory cartesian coordinates and supercavitaion characteristics under the conditions of initial water impact and underwater flight are captured by the high-speed digital imaging cameras placed orthogonally. Combining with the theory and simulation analysis, the compressible effet, basing on the projectile water entry hydrodynamic equation and motion equation, and flight attitude trajectory cartesian coordinates and supercavitaion characteristics at different times caused by different experimental conditions, the theoretical analytical model to predict the trajectory stability and damage of water entry projectiles can be obtained. It will discuss and gain insights into the mechanisms on trajectory stability and damage of different projectiles. The work in this study is very valuable and beneficial to provide theory support and scientific basis for kinetic energy projectile engineering structure design and control of high speed oblique water entry.

动能弹以亚声速和超声速斜入水的弹道稳定性和损伤是研究者必须面对的复杂难题和严重挑战。对其开展研究具有重要的科学意义和广阔的技术应用前景。小尺寸模型实验技术是研究弹体入水问题的主要方法之一。本项目采用高速数字正交成像和可视化技术,可转动的轻气炮系统和水箱，针对不同头形和长径比的弹体在500m/s-2000m/s速度范围内，以0-75度的入射角度，进行弹体从空气高速入水弹道稳定和损伤特性的试验研究。通过压力传感器和高速粒子图像测速技术分析弹体入水的压力场和速度场特性。利用正交分布的高速相机来获取弹体入水和水下运行的三维姿态轨迹坐标及空泡特性。结合理论与数值分析，考虑流体压缩效应，利用弹体入水动力学及运动学方程，弹体各个时刻姿态和空间运行轨迹坐标及空泡特性，建立弹体跨声速斜入水弹道稳定性和损伤特性的预报模型。

本项目采用高速数字正交成像和可视化技术,可转动的轻气炮系统和水箱，针对不同头形和长径比的弹体开展了弹体从空气高速入水的试验研究。利用弹体入水动力学及运动学方程，进行了弹体入水动力学和空泡扩展理论研究；通过压力传感器和高速阴影成像技术分析了弹体入水冲击波的压力和传播特性，结合理论及数值模拟进行了弹体高速入水冲击波理论及分布规律的研究；利用正交分布的高速相机获取了弹体入水和水下运行的三维姿态轨迹坐标及空泡特性，进行了弹体高速入水弹道稳定性的研究。本项研究为动能弹工程结构设计和高速斜入水控制提供了有益的理论支持和科学依据。