When a low-viscosity drop coalesces with a pool surface of the same liquid, it often portrays partial coalescence, where it pinches off a daughter droplet from its top. Such partial coalescence can also occur for a drop spreading on a strongly hydrophilic solid surface. Herein, we investigate the partial coalescence of a low-viscosity drop with a pool surface, when the viscosity of the miscible pool is changed from low to very high, in other words, spanning the conditions from a pool to a solid surface. We find that above a certain pool viscosity, the partial coalescence transitions to second-stage coalescence with a much smaller satellite droplet. This occurs because higher pool viscosity prevents drainage from the drop into the pool, which, in turn, increases the axial curvature in the neck connecting the primary satellite to the drop, thereby preventing the first-stage pinch-off.

中文翻译：

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较大粘度池上液滴的部分聚结

当低粘度液滴与相同液体的池表面聚结时，它通常表现出部分聚结，在那里它从顶部夹断子液滴。对于在强亲水性固体表面上铺展的液滴，也可能发生这种部分聚结。在这里，我们研究了低粘度液滴与池表面的部分聚结，当混溶池的粘度从低变为非常高时，换句话说，从池到固体表面的条件。我们发现，高于一定的池粘度，部分聚结转变为具有小得多的卫星液滴的第二阶段聚结。发生这种情况是因为较高的水池粘度阻止了水滴从水滴流入水池，这反过来又增加了连接主要卫星和水滴的颈部的轴向曲率，