Drop splash and breakup on cylindrical surfaces play an important role in a wide variety of industrial applications. In this work, water drops with a wide range of impact velocities (1.4 m/s–4.5 m/s) and cylindrical stainless steels with different diameters (1 mm–20 mm) are employed to investigate the asymmetric splash and breakup characteristics of drops impacting on cylindrical superhydrophobic surfaces. We identify two interesting phenomena, asymmetric splash and converging breakup. The splash behavior is found to be asymmetric in different directions, and the drops preferentially splash in the axial direction. Fundamentally, we propose two disparate splash thresholds, referring to the Weber number We and the diameter ratio D^* = D/D₀, in the azimuthal and axial directions, respectively. The converging breakup is caused by the much more rapid converging of the liquid rim in the axial direction than in the azimuthal direction. The aspect ratio β_zmax/β_xmax, governing the converging breakup, increases with We and decreases with D^*. Fortuitously, the splashing angle θ is demonstrated to only depend on D^* rather than We, and the relational expression of θ and D^* is provided. Ultimately, we put forward universal relations between the mean diameter and velocity of secondary droplets, resulting from the converging breakup, and the dimensionless parameter We/D^*. The results of this work are expected to provide valuable insights into anti-icing and microfluidics fields.

中文翻译：

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非对称飞溅和液滴破裂影响圆柱形超疏水表面

圆柱表面上的液滴飞溅和破裂在各种工业应用中都起着重要作用。在这项工作中，采用具有广泛冲击速度的水滴（1.4 m / s–4.5 m / s）和具有不同直径（1 mm–20 mm）的圆柱形不锈钢来研究水滴的非对称飞溅和破裂特性。撞击圆柱形超疏水表面。我们确定了两个有趣的现象，非对称飞溅和收敛破裂。发现飞溅行为在不同方向上是不对称的，并且液滴优选在轴向上飞溅。从根本上讲，我们提出了两个不同的飞溅阈值，分别是韦伯数We和直径比D ^* = D /D ₀分别在方位角和轴向。收敛破裂是由液体边缘在轴向上比在方位方向上更快的收敛所引起的。纵横比β _ZMAX / β _XMAX，治汇聚分手，与增加我们与降低d ^*。幸运地，证明了飞溅角θ仅取决于D ^*而不是We，并且θ和D ^*的关系表达式提供。最终，我们提出了由收敛破裂引起的次级液滴平均直径和速度之间的通用关系，以及无量纲参数We / D ^*。预期这项工作的结果将为防冰和微流体领域提供有价值的见解。