Stability of gravity-driven liquid films overflowing microstructures with sharp corners
Stability of gravity-driven liquid films overflowing microstructures with sharp corners
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DOI：
10.1103/physrevfluids.5.094001
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发表时间：
2020-09-02
影响因子：
2.7
通讯作者：
Repke, Jens-Uwe
中科院分区：
文献类型：
--
作者：
Bonart, Henning;Rajes, Sangitha;Repke, Jens-Uwe
我们报告的稳定性的薄液膜溢出单个微结构与尖角。微观结构为矩形和三角形。它们的高度和宽度分别是努塞尔膜厚度的0.25、0.5和0.75倍。为了观察稳定的，波浪形的，非常不稳定的膜，我们进行了模拟，雷诺数范围从10到70。通过耦合Cahn-Hilliard方程和Navier-Stokes方程描述了液膜和溢流气相的动力学过程。由此产生的模型形成了一个非常紧密耦合的非线性方程组。因此，我们仔细选择了解决方案策略，以实现高效和准确的大规模模拟。我们的研究结果表明，波的形成转移到更高的雷诺数相比，在光滑表面上的膜。如果最终形成波浪，则微结构导致不规则波浪。结果表明，微结构的形状和尺寸对溢流液膜的稳定性有很大的影响。
We report on the stability of thin liquid films overflowing single microstructures with sharp corners. The microstructures were of rectangular and triangular shape. Their heights and widths were 0.25, 0.5, and 0.75 times the Nusselt film thickness. To observe steady, wavy, and very unstable films we performed simulations with Reynolds numbers ranging from 10 to 70. The dynamics of the liquid film and the overflowing gas phase were described by the coupling between the Cahn-Hilliard and the Navier-Stokes equations. The resulting model forms a very tightly coupled and nonlinear system of equations. Therefore we carefully selected the solution strategy to enable efficient and accurate large-scale simulations. Our results showed that the formation of waves was shifted to higher Reynolds numbers compared to the film on a smooth surface. If waves were finally formed, the microstructures led to irregular waves. Our results indicate a great influence of the microstructure's shape and dimension on the stability of the overflowing liquid film.