Spontaneous shrinkage of drops and mass conservation in phase-field simulations
Spontaneous shrinkage of drops and mass conservation in phase-field simulations
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DOI：
10.1016/j.jcp.2006.11.020
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发表时间：
2007-04
期刊：
影响因子：
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通讯作者：
P. Yue;Chunfeng Zhou;James J. Feng
中科院分区：
文献类型：
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作者：
P. Yue;Chunfeng Zhou;James J. Feng
在这篇文章中，我们研究了使用相场模型模拟两相流时Cahn-Hilliard扩散对质量守恒的影响。即使相场变量λ是全局守恒的，当λ从体相中的预期值偏移时，液滴会自发地收缩。这些变化被发现是成比例的界面厚度，我们建议的准则，以尽量减少质量损失。此外，存在一个临界半径，低于该半径，液滴将最终消失。然而，在适当选择迁移率参数的情况下，该过程将比感兴趣的物理过程慢得多，因此对模拟几乎没有不良影响。
In this note, we examine the implications of Cahn–Hilliard diffusion on mass conservation when using a phase-field model for simulating two-phase flows. Even though the phase-field variable ϕ is conserved globally, a drop shrinks spontaneously while ϕ shifts from its expected values in the bulk phases. Those changes are found to be proportional to the interfacial thickness, and we suggest guidelines for minimizing the loss of mass. Moreover, there exists a critical radius below which drops will eventually disappear. With a properly chosen mobility parameter, however, this process will be much slower than the physics of interest and thus has little ill effect on the simulation.