射弹斜入水时流体动力特性及弹体水动力冲击载荷研究

Hydrodynamic characteristics of projectile oblique entry into water and hydrodynamic impulse load of projectile body

为了更好地研究射弹倾斜入水时流体的动力特性和弹体水动力冲击载荷的变化规律,基于雷诺平均的Navier-Stokes方程,结合STAR-CCM+软件的重叠网格技术,建立了圆柱弹体斜入水计算模型,利用欧拉多相流模型中的流体体积法计算分析了射弹斜入水时的流体动力特性和弹体受力规律,获得了弹体初始入水速度对入水深度的影响规律。研究发现:阻力系数峰值与初始入水速度正相关,射弹完全进入水中后,射弹所受阻力迅速趋于稳定;射弹入水撞击阶段产生的水雾会填充空泡内部,并促进空泡扩张,重力会影响空泡外形并使之不对称;当射弹出现尾拍现象时,会在尾部形成压差力。数值计算与实验结果对比表明:所采取的数值计算方法是可靠的、有效的。

In order to explore the hydrodynamic characteristics of projectile oblique entry into water and the variation law of hydrodynamic impulse load of projectile body,based on Reynolds averaged Navier-Stokes equations and combined STAR-CCM+software overlap grid technology,a calculating model of the cylindrical projectile angle into the water was set up.The projectile initial entry speed on the entry depth of the water was found by employing volume method using Eulerian multiphase flow model of fluid.The results show that the peak value of the resistance coefficient is positively correlated with the initial water entry velocity.The resistance instantly levels out with the projectile entry into the water.The water mist generated during the impact stage of the projectile will fill the interior of the cavity and promote the expansion of the cavity.Gravity will affect the shape of the cavity and make it asymmetric.When the tail beat phenomenon appears with the projectile,the pressure difference force will be formed in the tail.The comparison between numerical calculation and experimental results shows that the numerical calculation method is reliable and effective.