返回舱垂直自由入水砰击过程的数值模拟

文章数值研究返回舱垂直自由入水砰击过程中水气流场与返回舱运动之间的动力学与运动学耦合问题。水气两相流的流动方程选为非定常雷诺平均Navier-Stokes(URANS）方程和Realizable k-ε湍流模型，返回舱的运动方程选为刚体的一维平动方程，水气交界面的追踪采用流体体积函数（VOF）方法，返回舱与水面之间的相对运动采用动网格技术实现。在计算方法得到试验验证的基础上，数值研究了返回舱的不同触水速度、质量对入水过程中砰击力、加速度等参数的影响规律；给出了入水过程中加速度峰值与触水速度及质量之间的定量关系式；发现了返回舱底部的入水砰击压强峰值发生在入水初期，且压强峰值始终位于喷溅射流的根部。

Numerical Simulation on Vertical Water Entry Impact of a Recovery Module

The complex multiphase and fluid-structure interaction problem of the vertical water entry of a recovery module was numerically researched. The two-dimensional axisymmetrical unsteady Reynolds averaged Navier-Stokes(URANS) equation and Realizable k-ε turbulent equations were solved by the SIMPLE algorithm. The water impact on the recovery module in single-degree-of-freedom motion was simulated by dynamic mesh method. The air-water interface was tracked using the volume of fluid (VOF) model. The employed numerical methods were firstly validated by comparing simulation results with experimental data. The effects of slamming velocity and weight on slamming force were investigated. A relationship formula of the acceleration peak to variable velocities and weights was obtained. The maximum shock pressure on the recovery module occurred in the early stage when entrying into the water and the pressure peak is always located in the splash root close to the recovery module.