When a partially filled glass is gently tilted, the liquid can go over its brim without spilling. This happens because of the surface tension and has a direct indication when studying the emptying of a partially filled capillary by modifying the present mathematical criteria of critical emptying. Here, we present an experimental study of the edge effect on emptying a finite-lengthed horizontal capillary, a condition that has never been studied before. We observed that due to the edge meniscus from the finite length of the capillary, critical emptying conditions are significantly altered. Furthermore, by optimizing the edge parameters and the brim wetting effect, water can hold onto much wider capillary brims. We performed numerical simulations using realistic geometries and found excellent agreements with our experimental results. Our results generalize the capillary emptying criterion so that they can be used in realistic geometries and provide guidance in understanding a wide range of phenomena in microfluidics and optofluidics.

中文翻译：

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有限长毛细管的通用排空准则

当部分填充的玻璃轻轻倾斜时，液体可以越过其边缘，而不会溢出。这是由于表面张力而发生的，并且在通过修改当前的临界排空数学标准来研究部分填充的毛细管的排空时有直接的指示。在这里，我们提供了一个实验研究，该研究对清空有限长度的水平毛细管的边缘效应进行了研究，而这种条件以前从未被研究过。我们观察到，由于毛细管有限长度的边缘弯液面，严重的排空条件发生了显着变化。此外，通过优化边缘参数和边缘湿润效果，水可以固定在宽得多的毛细管边缘上。我们使用实际的几何形状进行了数值模拟，并发现与实验结果极好的一致性。