Inertia dominated drop collisions. I. On the universal flow in the lamella
Inertia dominated drop collisions. I. On the universal flow in the lamella
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DOI：
10.1063/1.3129282
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发表时间：
2009-05-01
影响因子：
4.6
通讯作者：
Tropea, Cam
中科院分区：
文献类型：
--
作者：
Roisman, Ilia V.;Berberovic, Edin;Tropea, Cam
这项研究致力于分析以惯性为主的轴对称液滴与干衬底或其他液滴的碰撞。所有以前的液滴碰撞理论和半经验模型都是基于这样的假设，即液滴在液膜中的流动和厚度主要由撞击条件决定，主要由雷诺数和韦伯数决定。在这项研究中，将现有的实验数据与现有的和新的关于不同撞击条件下跌落碰撞早期产生的薄层形状的数值模拟进行了比较。结果表明，在雷诺数和韦伯数足够高的情况下，薄膜厚度的演化几乎不依赖于粘度和表面张力。因此，这些结果完全改变了我们对液滴碰撞产生的流动的理解。此外，我们还证明了基于圆盘形变液滴形状近似的理论模型和基于能量平衡方法的模型是不正确的。最后，通过对液滴撞击对称平面的数值模拟，得到了液滴厚度、速度和压力的普遍无量纲分布。这些普适分布对于高影响的韦伯数和雷诺数是有效的。
This study is devoted to the analysis of inertia dominated axisymmetric drop collisions with a dry substrate or with another liquid drop. All the previous theoretical and semiempirical models of drop collisions are based on the assumption that the flow in the lamella and its thickness are determined by the impact conditions, mainly by the Reynolds and Weber numbers. In this study the existing experimental data are compared to existing and new numerical simulations for the shape of the lamella generated at the early times of drop impact for various impact conditions. The results show that if the Reynolds and Weber numbers are high enough, the evolution of the lamella thickness almost does not depend on the viscosity and surface tension. Therefore these results completely change our understanding of the flow generated by drop collisions. Moreover, we demonstrate that the theoretical models based on the approximation of the shape of the deforming drop by a disk and the models based on the energy balance approach are not correct. Finally, universal dimensionless distributions for the lamella thickness, velocity, and pressure are obtained from the numerical simulations of drop impact onto a symmetry plane (associated with the binary drop collisions). These universal distributions are valid for high impact Weber and Reynolds numbers.