Early stage of bubble spreading in a viscous ambient liquid
Early stage of bubble spreading in a viscous ambient liquid
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DOI：
10.1017/jfm.2023.404
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发表时间：
2023-06-07
影响因子：
3.7
通讯作者：
Gao，Peng
中科院分区：
文献类型：
--
作者：
Ming，He;Qin，Jian;Gao，Peng
我们以数值方式研究了粘性液体中气泡与光滑固体基质接触时的扩散动力学。基底具有部分润湿性，采用纳维滑移模型缓解了动接触线的奇异性。斯托克斯方程通过采用边界元法与自适应网格细化相结合来求解。这使我们能够实现足够小的滑移长度直至无量纲形式，这对于解决扩散早期阶段的局部界面结构至关重要。结果表明，气泡的早期扩散始终以接近接触线的反润湿液缘的生长和推进为特征，而宏观界面保持不变。接触线和边缘形态的演变取决于润湿性和滑移长度，并进行了参数研究。基于质量守恒，建立了边缘尺寸和扩散半径之间的关系。我们还提出了对传播早期接触线半径时间变化的分析预测，发现它遵循对数校正的线性关系而不是纯幂律。此外，对于二维和轴对称结构，气泡扩散的早期阶段在性质上是相似的。
We investigate numerically the spreading dynamics of a bubble coming into contact with a smooth solid substrate in a viscous liquid. The substrate is partially wettable, and the singularity of the moving contact line is relieved by adopting the Navier-slip model. The Stokes equations are solved by employing a boundary element method coupled with adaptive mesh refinement. This allows us to realize sufficiently small slip lengths down to in dimensionless form, which is crucial to resolve the local interface structures at the early stage of spreading. The results show that the early-stage spreading of the bubble is always characterized by the growth and propulsion of a dewetting liquid rim close to the contact line, while the macroscopic interface remains unchanged. The evolution of the contact line and the morphology of the rim depends on the wettability and the slip length, and a parametric investigation is performed. Based on mass conservation, a relation between the rim size and the spreading radius is established. We also propose an analytical prediction of the temporal variation in the contact line radius at the early stage of spreading, which is found to follow a logarithmically corrected linear relation rather than a pure power law. Moreover, the early stages of bubble spreading are qualitatively similar for two-dimensional and axisymmetric configurations.