A diffuse-interface immersed-boundary method for two-dimensional simulation of flows with moving contact lines on curved substrates
A diffuse-interface immersed-boundary method for two-dimensional simulation of flows with moving contact lines on curved substrates
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用于二维模拟弯曲基底上移动接触线流动的扩散界面浸入边界方法
DOI：
10.1016/j.jcp.2015.03.059
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发表时间：
2015-08
影响因子：
4.1
通讯作者：
Ding, Hang
中科院分区：
文献类型：
--
作者：
Liu, Hao-Ran;Ding, Hang
我们提出了一种在笛卡尔网格上模拟弯曲衬底上移动接触线(MCL)流动的方法。该方法结合了浸没边界方法、三分量扩散界面模型和特征MCL模型。浸没边界法能够在固体表面精确地执行无滑移边界条件，从而绕过气体和液体通过对流进入固体的情况。另一方面，采用三组分扩散界面模型可以防止气体和液体在界面演化过程中通过扩散通量渗入到固体基材中。这两种方法的结合似乎有效地保存了计算中的相质量。特征MCL模型不仅允许接触线在弯曲的边界上移动，而且使气液界面以与规定接触角一致的角度与固体相交，即使在固体衬底表面切线变化的情况下也是如此。我们通过各种数值实验来检验该方法的性能。通过模拟液滴在圆柱体上的扩散，验证了液滴在平衡状态下的质量守恒和界面形状。通过模拟液滴在平板衬底上的扩散，验证了运动接触线的动力学行为，并将数值结果与理论预测和先前的实验观测结果进行了比较。该方法还被应用于具有弯曲边界和移动接触线的流动的模拟，例如球体的跌落冲击和球体的入水。最后，我们研究了二维液滴在由一簇圆柱体组成的多孔衬底中的穿透过程。
We propose an approach to simulate flows with moving contact lines (MCLs) on curved substrates on a Cartesian mesh. The approach combines an immersed boundary method with a three-component diffuse-interface model and a characteristic MCL model. The immersed boundary method is able to accurately enforce the no-slip boundary condition at the solid surface, thereby circumventing the penetration of the gas and the liquid into the solid by convection. On the other hand, using the three-component diffuse-interface model can prevent the gas and liquid from infiltrating into the solid substrate through the diffusive fluxes during the interface evolution. A combination of these two methods appears to effectively conserve the mass of the phases in the computation. The characteristic MCL model not only allows the contact lines to move on the curved boundaries, but makes the gas–liquid interface to intersect the solid object at an angle in consistence with the prescribed contact angle, even with the variation of surface tangent at the solid substrate. We examine the performance of the approach through a variety of numerical experiments. The mass conservation and interface shapes at equilibrium were tested through the simulation of drop spreading on a circular cylinder. The dynamic behaviors of moving contact lines were validated by simulating the droplet spreading on a flat substrate, and we compared the numerical results against theoretical predictions and previous experimental observations. The method was also applied to the simulations of flows with curved boundaries and moving contact lines, such as drop impact on a sphere and water entry of a sphere. Finally, we studied the penetration process of a two-dimensional drop into a porous substrate that consists of a cluster of circular cylinders.
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影响因子：
3.7
作者：
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通讯作者：
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影响因子：
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作者：
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影响因子：
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作者：
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通讯作者：
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