论文标题
粘性液滴撞击软底物
Viscous droplet impingement on soft substrates
论文作者
论文摘要
撞击软底物上的粘性液滴可能会表现出几种不同的行为，包括反复弹跳，润湿和盘旋，即在撞击后散布和缩回而不会反弹或润湿。我们通过系统地改变底物弹性，影响速度和液体粘度来实验研究实现这些特征行为的条件。对于每种底物弹性，对润湿的过渡被确定为Weber数的依赖性，我们在Ohnesorge数字上测量了液滴的动能对其表面能的依赖性，这将粘度与惯性和毛细血管进行了比较。我们发现，尽管对于相对刚性的底物，我们在润湿过渡时单调降低，但它表现出违反直觉的行为，它首先增加，然后逐渐减少较软的底物。我们通过实验确定最大WEBER数量的依赖性，允许对底物弹性产生非润湿影响，并表明它为从液体到软表面和不可构造表面的各种表面提供了极好的定量液体驱除度的定量度量。
Viscous droplets impinging on soft substrates may exhibit several distinct behaviours including repeated bouncing, wetting, and hovering, i.e., spreading and retracting after impact without bouncing back or wetting. We experimentally study the conditions enabling these characteristic behaviours by systematically varying the substrate elasticity, impact velocity and the liquid viscosity. For each substrate elasticity, the transition to wetting is determined as the dependence of the Weber number We, which measures the droplet's kinetic energy against its surface energy, on the Ohnesorge number Oh, which compares viscosity to inertia and capillarity. We find that while We at the wetting transition monotonically decreases with Oh for relatively rigid substrates, it exhibits a counter-intuitive behaviour in which it first increases then gradually decreases for softer substrates. We experimentally determine the dependence of the maximum Weber number allowing non-wetting impacts on the substrate elasticity and show that it provides an excellent quantitative measure of liquid repellency for a wide range of surfaces, from liquid to soft surfaces and non-deformable surfaces.
