Chu Hong-Yu, Fei Hsiang-Ting
Department of Physics, National Chung Cheng University, ChiaYi 62102, Taiwan.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Jun;89(6):063011. doi: 10.1103/PhysRevE.89.063011. Epub 2014 Jun 19.
We have investigated the behavior of bouncing drops on a liquid surface by using particle image velocimetry analysis. A drop on an oscillating liquid surface is observed to not coalesce with the liquid and to travel along the surface if the oscillation is strong enough. A streaming vortex pair, induced by the alternatively distorted liquid surface, shows up below a bouncing drop. The time-averaged flow fields of the vortices are measured. In our quasi-one-dimensional setup, there are three stable distances for the drops, which can be characterized by the Faraday wavelength. The interactions of the vortex-mediated bouncing drops are deduced from the streamlines in the liquid bulk. We further show that a three-dimensional vortex ring is induced by a bouncing drop in a square cell.
我们通过粒子图像测速分析研究了液面上弹跳液滴的行为。观察到，如果振荡足够强烈，振荡液面上的液滴不会与液体合并，而是会沿着液面移动。由交替变形的液面诱导产生的一对流动涡旋出现在弹跳液滴下方。测量了涡旋的时间平均流场。在我们的准一维装置中，液滴存在三个稳定距离，这些距离可以用法拉第波长来表征。从液体主体中的流线推导出涡旋介导的弹跳液滴之间的相互作用。我们进一步表明，方形单元中的弹跳液滴会诱导产生三维涡环。
