论文标题
被薄和厚的流体膜覆盖的固体上的滴水吞没
Engulfment of a drop on solids coated by thin and thick fluid films
论文作者
论文摘要
当水滴接触不混溶的油膜时，它会显示复杂的界面动力学。接触后，油会扩散到液滴的液体空气界面上，首先形成曲率，该曲率驱动明显的下降运动，然后完全吞噬滴水。我们使用基于保守相位场模型和实验的三相晶格玻璃体模拟研究了这一流。使用ohnesorge数字$ oh $作为$ r/h $的功能，惯性和粘性有限的动态，这是初始滴度半径$ r $和胶片高度$ h $之间的比率。这两个制度都表明，明显的传播半径$ r $相当独立于胶片高度，并且随时间$ t $作为$ r \ sim t^{1/2} $ for $ oh \ ll 1 $，而$ oh \ gg 1 $ as $ r \ r \ r \ sim t^{2/5} $。对于$ OH \ gg 1 $，我们通过实验表明，这种不混溶的表观扩散运动与可混杂的滴影胶合融合案例类似。但是，与明显的传播相反，我们发现较晚的吞噬动力和最终接口概况受到$ h/r $的比率显着影响。
When an aqueous drop contacts an immiscible oil film, it displays complex interfacial dynamics. Upon contact the oil spreads onto the drop's liquid-air interface, first forming a curvature that drives an apparent drop spreading motion and later fully engulfing the drop. We study this flow using both 3-phase Lattice-Boltzmann simulations based on the conservative phase field model and experiments. Inertially and viscously limited dynamics are explored using the Ohnesorge number $Oh$ as a function of $R/H$, the ratio between the initial drop radius $R$ and the film height $H$. Both regimes show that the apparent spreading radius $r$ is fairly independent of the film height, and scales with time $T$ as $r\sim T^{1/2}$ for $Oh\ll 1$ and for $Oh\gg 1$ as $r\sim T^{2/5}$. For $Oh\gg 1$ we show experimentally that this immiscible apparent spreading motion is analogous with the miscible drop-film coalescence case. Contrary to the apparent spreading, however, we find that the late time engulfment dynamics and final interface profiles are significantly affected by the ratio of $H/R$.
