考虑相互碰撞影响的月壤颗粒运动轨迹计算方法研究

针对登月着陆器下降过程扬起月壤颗粒的运动轨迹及空间分布问题, 提出了考虑月壤颗粒发生完全弹性碰撞和非完全弹性碰撞两种情况的月壤颗粒运动轨迹计算方法. 根据质量守恒和能量守恒定律确定月壤颗粒相互碰撞后的速度, 通过羽流场与月壤颗粒的流固耦合相互迭代计算方法, 获得被扬起的月壤颗粒在羽流场和相互碰撞共同作用下随时间的运动轨迹和空间分布. 基于美国Apollo 11登月过程实测数据, 采用数值模拟对该方法进行验证. 结果表明, 考虑月壤颗粒相互碰撞的影响后, 其运动规律出现较明显的扩散趋势. 进一步考虑月壤颗粒相互碰撞引起能量损失的影响后, 月壤颗粒的扩散趋势有所减弱, 并且扬起的高度随着恢复系数的减小而降低. 

Method on Calculation of Lunar Soil Particles Trajectories Considering Collision Effect

Regarding to the trajectory and mass distribution of lunar soil particles which are lifted by the lunar lander during the descending stage, a method considering the particles' collision effect is proposed. Based on the law of mass and energy conservation, the speed of regolith particles after collision is determined, and through the iterative calculations of fluid-structure interactions, the mass distribution caused both by collision effect and lunar lander effect on the lunar soil particles is presented. Through the measured data from the US Apollo 11 descending and landing on the lunar surface, the method are tested and verified by the numerical simulation. The analysis result shows that after the regolith particles colliding with each other having been considered, their trajectories have a more obvious tendency to spread. Furthermore, after the collision energy loss having been considered, the tendency to spread of regolith particles is weakened. And the smaller the coefficient of restitution is, the lower the raising height of the lunar soil particle will be.