Liu Qingzhe, Lo Jack Hau Yung, Li Ye, Liu Yuan, Zhao Jinyu, Xu Lei
Department of Physics, The Chinese University of Hong Kong, Hong Kong, China.
CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
Nat Commun. 2021 May 24;12(1):3068. doi: 10.1038/s41467-021-23138-4.
The impact and splash of liquid drops on solid substrates are ubiquitous in many important fields. However, previous studies have mainly focused on spherical drops while the non-spherical situations, such as raindrops, charged drops, oscillating drops, and drops affected by electromagnetic field, remain largely unexplored. Using ferrofluid, we realize various drop shapes and illustrate the fundamental role of shape in impact and splash. Experiments show that different drop shapes produce large variations in spreading dynamics, splash onset, and splash amount. However, underlying all these variations we discover universal mechanisms across various drop shapes: the impact dynamics is governed by the superellipse model, the splash onset is triggered by the Kelvin-Helmholtz instability, and the amount of splash is determined by the energy dissipation before liquid taking off. Our study generalizes the drop impact research beyond the spherical geometry, and reveals the potential of using drop shape to control impact and splash.
液滴对固体基底的撞击和飞溅在许多重要领域中普遍存在。然而，以往的研究主要集中在球形液滴上，而诸如雨滴、带电液滴、振荡液滴以及受电磁场影响的液滴等非球形情况在很大程度上仍未得到探索。我们利用铁磁流体实现了各种液滴形状，并阐明了形状在撞击和飞溅中的基本作用。实验表明，不同的液滴形状在铺展动力学、飞溅起始和飞溅量方面产生了很大差异。然而，在所有这些差异之下，我们发现了适用于各种液滴形状的通用机制：撞击动力学由超椭圆模型控制，飞溅起始由开尔文 - 亥姆霍兹不稳定性触发，飞溅量由液体起飞前的能量耗散决定。我们的研究将液滴撞击研究扩展到了非球形几何形状之外，并揭示了利用液滴形状控制撞击和飞溅的潜力。
