Symmetry breaking in drop bouncing on curved surfaces.
Symmetry breaking in drop bouncing on curved surfaces.
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DOI：
10.1038/ncomms10034
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发表时间：
2015-11-25
影响因子：
16.6
通讯作者：
Wang Z
中科院分区：
文献类型：
--
作者：
Liu Y;Andrew M;Li J;Yeomans JM;Wang Z
液滴对固体表面的冲击在自然界中是普遍存在的，并且在许多工业过程中具有实际重要性。撞击平面的液滴在整个撞击过程中保持圆形对称。在这里，我们表明，一个下降撞击Echevaria叶表现出不对称的弹跳动态与不同的扩展和收缩沿着两个垂直的方向。这是圆柱形叶片的直接结果，圆柱形叶片具有与液滴相当的大小的凸/凹结构。系统的模拟表面和格子玻尔兹曼模拟实验研究表明，这种新的现象的结果从一个不对称的动量和质量分布，允许优先流体泵周围的下降边缘。弹跳的不对称性导致接触时间减少约40%。 设计水不会润湿的超疏水表面对于从水收集到自清洁的许多应用至关重要。在这里，Liu等人展示了如何最小化液滴与固体表面的接触，该固体表面具有与液滴大小相当的凸和凹宏观纹理。
The impact of liquid drops on solid surfaces is ubiquitous in nature, and of practical importance in many industrial processes. A drop hitting a flat surface retains a circular symmetry throughout the impact process. Here we show that a drop impinging on Echevaria leaves exhibits asymmetric bouncing dynamics with distinct spreading and retraction along two perpendicular directions. This is a direct consequence of the cylindrical leaves that have a convex/concave architecture of size comparable to the drop. Systematic experimental investigations on mimetic surfaces and lattice Boltzmann simulations reveal that this novel phenomenon results from an asymmetric momentum and mass distribution that allows for preferential fluid pumping around the drop rim. The asymmetry of the bouncing leads to ∼40% reduction in contact time. Designing superhydrophobic surfaces that water does not wet is crucial for many applications ranging from water harvesting to self-cleaning. Here, Liu et al. show how to minimize the contact of liquid drops impacting on solid surfaces with convex and concave macrotextures comparable to the size of drops.