Abstract Droplets impacting on superhydrophobic surfaces with submillimetric or millimetric macrotextures can rebound completely after a short contact time, which is of practical importance in applications like self-cleaning and anti-icing. Many researches have been done on the centered impact, but the off-centered impact is rarely studied, even though it occurs more often. In the present work, we investigate the off-centered droplet impact on single-ridge superhydrophobic surfaces and focus on the morphologic evolution and contact time. We identify six typical morphologic evolution types as off-centered distance changes, with the centered impact and flat impact being the two extreme types. A theoretical classification model is proposed to predict the ranges of off-centered distance for different types and the regime maps of morphologic evolution types are presented. The effects of Weber number, off-centered distance and structural parameters on the contact time are explored. Under the current experimental conditions, the contact time increases linearly with off-centered distance when the off-centered distance exceeds a certain value, and the linear relationship is independent of Weber number and structural parameters. This work extends the fundamental knowledge of droplet impact and could be useful for related engineering applications.

中文翻译：

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偏心液滴对单脊超疏水表面的影响

摘要 液滴撞击具有亚毫米或毫米宏观纹理的超疏水表面可以在很短的接触时间后完全反弹，这在自清洁和防冰等应用中具有重要的实际意义。许多研究已经对中心影响进行了研究，但很少对偏离中心的影响进行研究，尽管它发生的频率更高。在目前的工作中，我们研究了偏心液滴对单脊超疏水表面的影响，并专注于形态演变和接触时间。我们将六种典型的形态演化类型确定为偏心距离变化，中心影响和平面影响是两种极端类型。提出了一种理论分类模型来预测不同类型的偏心距离范围，并给出了形态演化类型的状态图。探讨了韦伯数、偏心距离和结构参数对接触时间的影响。在目前的实验条件下，当偏心距离超过一定值时，接触时间随偏心距离线性增加，且这种线性关系与韦伯数和结构参数无关。这项工作扩展了液滴撞击的基础知识，可能对相关工程应用有用。当偏心距离超过一定值时，接触时间随偏心距离线性增加，且线性关系与韦伯数和结构参数无关。这项工作扩展了液滴撞击的基础知识，可能对相关工程应用有用。当偏心距离超过一定值时，接触时间随偏心距离线性增加，且线性关系与韦伯数和结构参数无关。这项工作扩展了液滴撞击的基础知识，可能对相关工程应用有用。