论文标题
能量稳定的方法，用于对表面活性剂的液滴撞击的相位模拟
Energy stable methods for phase-field simulation of droplet impact with surfactants
论文作者
论文摘要
本文致力于在存在表面活性剂的情况下对液滴影响固体底物的数值研究。我们在能量变化的框架中提出问题，并引入了不可压缩的Cahn-Hilliard-Navier-Stokes系统，用于两相流的相位模型。 Flory-Huggins潜力和广义Navier边界条件用于解释可溶性表面活性剂和移动接触线。基于凸的分裂和压力稳定技术，我们为该模型开发了无条件的能量稳定方案。针对一阶方案，严格证明了原始能量的离散能量耗散法。使用有限差方法在具有轴对称的三维圆柱坐标中实现数值方法。使用该模型的建议方法，我们在一系列数值实验中系统地研究了清洁和受污染的液滴（带有表面活性剂）的影响动力学。通常，在干净的情况下，受污染滴落的冲击动力学的耗散量小，并且造成污染的滴滴更有可能发生拓扑变化。添加表面活性剂可以显着影响影响现象，从而增强对亲水性表面的依从性效应并在疏水表面上飞溅。还获得了一些与实验的定量协议。
This paper is devoted to the numerical study of droplet impact on solid substrates in presence of surfactants. We formulate the problem in an energetically variational framework and introduce an incompressible Cahn-Hilliard-Navier-Stokes system for the phase-field modeling of two-phase flows. Flory-Huggins potential and generalized Navier boundary condition are used to account for soluble surfactants and moving contact lines. Based on the convex splitting and pressure stabilization technique, we develop unconditionally energy stable schemes for this model. The discrete energy dissipation law for the original energy is rigorously proved for the first-order scheme. The numerical methods are implemented using finite difference method in three-dimensional cylindrical coordinates with axisymmetry. Using the proposed methods for this model, we systematically study the impact dynamics of both clean and contaminated droplets (with surfactants) in a series of numerical experiments. In general, the dissipation in the impact dynamics of a contaminated drop is smaller than that in the clean case, and topological changes are more likely to occur for contaminated drops. Adding surfactants can significantly influence the impact phenomena, leading to the enhancement of adherence effect on hydrophilic surfaces and splashing on hydrophobic surfaces. Some quantitative agreements with experiments are also obtained.
