水滴撞击固体界面问题的Level Set数值模拟

Level Set Method for Numerical Simulation of Droplets Impacting on Solid Interface

摘要: Level Set界面追踪方法对于大变形及复杂拓扑结构变化的多相流问题具有一定的优势。本文利用RGFM(Riemann Ghost Fluid Method)定义界面边界条件，然后求解可压缩欧拉方程，用五阶WENO格式推进Level Set函数从而更准确的捕捉界面，处理界面两边密度比为1000的水气多相流运动问题，通过模拟两个不同形状的水滴与平板撞击后的形态变化及其运动过程，并计算运动过程中的水滴损失率，验证方法的准确性，进而了解水滴撞击特性，为研究飞行器部件表面结冰数值模拟提供技术积累。

Abstract: Level Set method show advantage of dealing with multiphase flows where interfaces can make large deformation and complex topological change. In this paper, we first use the Riemann ghost fluid method (RGFM) advanced by Wang et al. to define the boundary conditions and then solve the compressible Euler equations, using 5th WENO scheme to update level set function which can capture interface more accurately. Based on the current scheme we can easily simulate the multiphase flows which have density ratio of 1000 between two fluids, such as water and gas .In this work, we simulate the movement and topological changes of two droplets which are different in shape when they impact and splash on the solid interface. At the same time we compute the lost ratio of droplet to validate the accuracy of accurate algorithm. Based on the obtained numerical results, we can get the trajectory of droplets. It is helpful to accurately simulate the procedure of icing on the surface of aircraft.