Valves used to control liquid filling and draining processes from storage typically need to be actuated. Here, we show that similar flow enabling and restricting operations can be achieved through millimeter scale holes that function according to the amount of hydrostatic pressure applied without any other intervention. This phenomena is exhibited using receptacles where the base is made of either a hydrophilic or superhydrophobic substrate with hole sizes ranging from 1.0–2.0 mm. The construction is such that the drainage flow velocities are of the same order in both substrates and follow Torricelli’s law trends. Nevertheless, the primary mechanisms responsible for resisting the onset of flow in each substrate are different; nonbreaching of the advancing contact angle threshold in the former, and stable maintenance of an elastic-like deformation of the liquid–gas interface that is connected to the surrounding plastron in the latter. These differences are demonstrated using an upward jet of water delivered to the orifice, where a discharging flow from the hydrophilic base occurred before the threshold hydrostatic pressure condition was attained, while liquid from the jet is subsumed into the liquid body of the receptacle with the superhydrophobic base without any leakage. These findings portend advantages in simplicity and robustness for a myriad of liquid-related processes.

中文翻译：

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毫米大小的孔阻尼

通常需要控制用于控制液体从存储中的填充和排放过程的阀门。在此，我们表明，通过毫米级的孔可以实现类似的流量启用和限制操作，这些孔根据所施加的静水压力大小而起作用，而无需任何其他干预。这种现象在使用底座由亲水性或超疏水性基材制成且孔尺寸范围为1.0-2.0 mm的容器中表现出来。这样的构造使得在两个基板上的排水流速都处于相同的数量级，并且遵循托里切利定律的趋势。然而，负责抵抗每种基质中的流动开始的主要机制是不同的。在前者中不违反前进接触角阈值，并稳定维持液-气界面的弹性状变形，该界面与周围的门相连。这些差异通过向孔口输送水的向上喷射来证明，其中从亲水性基体排出的水在达到阈值静水压条件之前就已发生，而来自喷射流的液体则以超疏水性被吸收到容器的液体中底座无任何泄漏。这些发现预示了无数与液体有关的过程在简单性和耐用性方面的优势。其中在达到阈值静水压条件之前发生了从亲水性碱的排出流，而来自射流的液体被包含在具有超疏水性碱的容器的液体中而没有任何泄漏。这些发现预示了无数与液体有关的过程在简单性和耐用性方面的优势。其中在达到阈值静水压条件之前发生了从亲水性碱的排出流，而来自射流的液体被包含在具有超疏水性碱的容器的液体中而没有任何泄漏。这些发现预示了无数与液体有关的过程在简单性和耐用性方面的优势。