论文标题
水滴的影响力落在超疏水表面
Impact forces of water drops falling on superhydrophobic surfaces
论文作者
论文摘要
由于正常的反作用力，在对刚性底物的影响后，液态下降，变形和扩散。随后，如果底物不润湿，则滴缩回然后跳下。正如我们在这里显示的那样，不仅影响本身与正常力的时间演变中的独特峰有关，而且是迄今为止未知的脱离峰。我们表征了峰值并阐明它们与降落冲击过程的不同阶段的关系。第二个峰出现的时间与沃辛顿射流的形成相吻合，通过流动式涌入，它与冲击速度无关。但是，该峰的大小由滴的惯性和表面张力决定。我们表明，即使是低速影响也可能导致正常力的高峰，即当由于滴水中的空气腔崩溃而发生更明显的奇异沃辛顿射流时。
A falling liquid drop, after impact on a rigid substrate, deforms and spreads, owing to the normal reaction force. Subsequently, if the substrate is non-wetting, the drop retracts and then jumps off. As we show here, not only is the impact itself associated with a distinct peak in the temporal evolution of the normal force, but also the jump-off, which was hitherto unknown. We characterize both peaks and elucidate how they relate to the different stages of the drop impact process. The time at which the second peak appears coincides with the formation of a Worthington jet, emerging through flow-focusing, and it is independent of the impact velocity. However, the magnitude of this peak is dictated by the drop's inertia and surface tension. We show that even low-velocity impacts can lead to a surprisingly high peak in the normal force, namely when a more pronounced singular Worthington jet occurs due to the collapse of an air cavity in the drop.
