Clogging and avalanches in quasi-two-dimensional emulsion hopper flow
Clogging and avalanches in quasi-two-dimensional emulsion hopper flow
复制标题
准二维乳液料斗流中的堵塞和雪崩
DOI：
10.1103/physreve.105.014603
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发表时间：
2022
影响因子：
2.4
通讯作者：
Weeks, Eric R.
中科院分区：
文献类型：
--
作者：
Hong, Xia;Desmond, Kenneth W.;Chen, Dandan;Weeks, Eric R.
我们通过实验和计算研究了准二维乳化液通过收缩漏斗形状的流动。我们的面积分数高于干扰，因此液滴总是彼此接触，并且在许多情况下高度变形。在最低的流速下，液滴经常堵塞，从而通过间歇性的雪崩离开料斗。在最高流速下，液滴连续流出。这两种行为之间的转变是平均应变速率的一个相当平滑的函数。雪崩的特征是液滴离开料斗的时间间隔呈幂律分布，雪崩之间的间隔很长。我们的计算研究通过向系统添加柔性顺应性（换句话说，样品室的有限刚度）来再现实验观察结果。这种顺应性导致高流量下的连续流动，并允许系统在低流量下堵塞导致雪崩。计算结果表明，流速和柔度的相互作用控制着雪崩的发生。
We experimentally and computationally study the flow of a quasi-two-dimensional emulsion through a constricting hopper shape. Our area fractions are above jamming such that the droplets are always in contact with one another and are in many cases highly deformed. At the lowest flow rates, the droplets often clog and thus exit the hopper via intermittent avalanches. At the highest flow rates, the droplets exit continuously. The transition between these two types of behaviors is a fairly smooth function of the mean strain rate. The avalanches are characterized by a power-law distribution of the time interval between droplets exiting the hopper, with long intervals between the avalanches. Our computational studies reproduce the experimental observations by adding a flexible compliance to the system (in other words, a finite stiffness of the sample chamber). The compliance results in continuous flow at high flow rates, and allows the system to clog at low flow rates leading to avalanches. The computational results suggest that the interplay of the flow rate and compliance controls the presence or absence of the avalanches.