Computing the viscous effect in early-time drop impact dynamics
Computing the viscous effect in early-time drop impact dynamics
复制标题
DOI：
10.1017/jfm.2022.445
复制
发表时间：
2018-11
影响因子：
3.7
通讯作者：
Shruti Mishra;S. Rubinstein;C. Rycroft
中科院分区：
文献类型：
--
作者：
Shruti Mishra;S. Rubinstein;C. Rycroft
液滴对固体表面的冲击涉及许多相互交织的物理效应，受液滴速度、表面张力、环境压力和液体粘度等因素的影响。Kolinski等人的实验。(物理。Rev.Lett.，第112卷，第13期，2014b，134501页)表明，液-气界面甚至在接触之前就开始偏离固体表面。他们发现，界面的提离开始于一个关键时间，该时间与液体运动粘度的平方根成比例。为了理解这一点，我们研究了在存在中间气体层的情况下，液滴向固体表面的靠近。我们采用数值方法来求解流体的Navier-Stokes方程，以及气体的可压缩润滑方程。用这种方法，我们恢复了实验中捕获的液体粘度对液滴撞击的早期时间效应，但我们的结果表明，提离时间和液体运动粘度具有比平方根标度关系更复杂的依赖关系。我们还预测了液气界面的界面张力对液滴碰撞的影响，结果表明，液气界面张力对提离行为起中介作用。
Abstract The impact of a liquid drop on a solid surface involves many intertwined physical effects, and is influenced by drop velocity, surface tension, ambient pressure and liquid viscosity, among others. Experiments by Kolinski et al. (Phys. Rev. Lett., vol. 112, no. 13, 2014b, p. 134501) show that the liquid–air interface begins to deviate away from the solid surface even before contact. They found that the lift-off of the interface starts at a critical time that scales with the square root of the kinematic viscosity of the liquid. To understand this, we study the approach of a liquid drop towards a solid surface in the presence of an intervening gas layer. We take a numerical approach to solve the Navier–Stokes equations for the liquid, coupled to the compressible lubrication equations for the gas, in two dimensions. With this approach, we recover the experimentally captured early time effect of liquid viscosity on the drop impact, but our results show that lift-off time and liquid kinematic viscosity have a more complex dependence than the square-root scaling relationship. We also predict the effect of interfacial tension at the liquid–gas interface on the drop impact, showing that it mediates the lift-off behaviour.