论文标题
合并或不结合：液滴和表面张力梯度
To coalesce or not to coalesce: Droplets and surface tension gradients
论文作者
论文摘要
我们在数值上研究了两个无线电液滴$ r_0 $的共聚动力学。将液滴放置在刚性基板的顶部，其接触角为$θ_{eq。} =π/9 $。具有高度润湿的基材（$θ_{eq} \llπ/2 $）理论预测，桥高（$ h_0 $）根据$ h_0（t）\ sim t^{2/3}缩放。$可以通过例如。表面张力梯度（$ \partial_xγ\ neq 0 $）。例如，这些梯度出现在传热，表面活性剂或具有不同但可溶的液体的情况下。这些梯度不是合并的，而是导致稳定的两个液滴状态。在这项工作中，我们专注于这个问题的两个方面。第一个是表面张力的具体选择，因此使其在空间上相关。第二个是降低尺度朝着一个脱节压力变得重要的制度。我们发现，鉴于表面张力有急剧的梯度，可以抑制合并。如果将此梯度涂抹，我们找到了与$ 2/3 $ power-Law的中间协议。在较大的涂抹宽度的极限下，我们观察到不对称的聚结。
We numerically study the coalescence dynamics of two sessile droplets with radii $R_0$. The droplets are placed on top of a rigid substrate with a contact angle of $θ_{eq.} = π/9$. Having a highly wettable substrate ($θ_{eq} \ll π/2$) theory predicts that the bridge height ($h_0$) scales according to $h_0(t) \sim t^{2/3}.$ This behavior can be altered with e.g. surface tension gradients ($\partial_xγ\neq 0$). These gradients appear for example with heat transfer, surfactants or having different but miscible liquids. Instead of coalescence, these gradients can lead to a stable two droplet state. In this work, we focus on two aspects of this problem. The first one is the concrete choice of the surface tension, therefore making it spatially correlated. The second one is the reduction of scale towards a regime in which the disjoining pressure becomes important. We find that coalescence can be suppressed, given that there is a sharp gradient in surface tension. If this gradient is smeared, we find an intermediate agreement with the $2/3$ power-law. In the limit of large smearing width, we observe an asymmetric coalescence.
