The formation and expansion of a toroidal drop moving in a viscous fluid
The formation and expansion of a toroidal drop moving in a viscous fluid
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在粘性流体中运动的环形液滴的形成和膨胀
DOI：
10.1063/1.864511
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发表时间：
1984
影响因子：
4.6
通讯作者：
A. Acrivos
中科院分区：
文献类型：
--
作者：
M. Kojima;E. Hinch;A. Acrivos
在液滴雷诺数较小的情况下，研究了初始球形液滴在重力作用下在与其完全相容的另一种流体中运动的变形。实验发现，这样的液滴演化成一个随后膨胀的开放环面，并从理论上分析了两种极限液滴几何形状：(I)轻微变形的球形液滴和(Ii)高度膨胀、细长的开放环面。在零界面张力和蠕变流动的假设下，该理论对液滴演化的初始阶段提供了定性的描述[情况(I)]，但不能解释在变形后期观察到的液滴扩展[情况(II)]。另一方面，如果在分析中保留小惯性效应，该理论预测具有任意截面几何形状的细长开放流体环将在不改变形状到雷诺数的一阶的情况下膨胀。理论预测的膨胀速率与实验测量的定量比较表明，液滴界面上可能存在一个与时间相关的小界面张力。
The deformation of an initially spherical liquid drop moving under the action of gravity in another fluid with which it is completely miscible is investigated under conditions of small values of the drop Reynolds number. It is found experimentally that such a drop evolves into an open torus which subsequently expands, and this phenomenon is examined theoretically for two limiting drop geometries: (i) a slightly deformed spherical drop, and (ii) a highly expanded, slender open torus. Under the assumptions of zero interfacial tension and creeping flow, the theory provides a qualitative description for the initial stages of the drop evolution [case (i)], but is unable to account for the observed drop expansion during latter stages of deformation [case (ii)]. On the other hand, if small inertial effects are retained in the analysis, the theory predicts that a slender open fluid torus possessing an arbitrary cross‐sectional geometry will expand without change of shape to first order in Reynolds number. Quantitative comparisons of theoretically predicted rates of expansion with experimental measurements suggest the possible existence of a small, time‐dependent interfacial tension across the drop interface.