不同头型运动体高速入水空泡数值模拟

Numerical simulation of high-speed water entry cavity of cylinders

运动体头型对其入水流场的流动分布、流体动力及入水弹道均有较大的影响.针对此问题基于有限体积法离散、求解雷诺平均的Navier-Stokes方程,考虑空化效应,并引入动网格技术,对带有不同角度锥头圆柱体的高速入水问题开展数值模拟研究,得到不同头型条件下高速入水运动参数及空泡形态发展规律、流场的压力分布及速度分布规律,分析了头型对入水空泡流场的影响.研究结果表明,空泡半径的扩张规律受头型及其阻力系数的影响,半径大小与阻力系数近似满足一定的关系式;入水初期,运动体头部受到极强的冲击载荷,锥角越大,压力峰值也越高;锥体表面压力系数与锥角大小直接相关,锥角较大时压力系数也较大.同时,锥角大小对运动体肩部排开水的速度也有较大影响,运动体在相同速度下,锥角较大时,肩部排开水的速度也较大.

The fluid dynamics of the multiphase flow induced by water entry of high speed projectiles with various heads are different. Numerical simulation for modeling the high-speed water entry problem of projectiles with different heads at an initial impact velocity was performed. Finite Volume Method was introduced to solve the Reynolds Averaged Navier-Stokes equations, and the motion of the projectiles and cavity formation were obtained. The results showed that the cavity radius was related to the angle and the drag coefficient of the cone heads. The distribution of pressure coefficient on the cone and velocity around the shoulder of the projectiles were also obtained. During the initial stage of the water entry, there will be an extremely high pressure load. When the angle of the cone head is larger, the pressure gets higher, the pressure coefficient is larger, and the velocity of the water which is arranged by the projectile is higher.