Droplet formation and scaling in dense suspensions
Droplet formation and scaling in dense suspensions
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DOI：
10.1073/pnas.1111060109
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发表时间：
2012-03-20
影响因子：
11.1
通讯作者：
Jaeger, Heinrich M.
中科院分区：
文献类型：
--
作者：
Miskin, Marc Z.;Jaeger, Heinrich M.
当从喷嘴挤出稠密悬浮液时，液滴分离可以发生类似于纯液体的分离。虽然在纯液体中，液滴分离过程通过自相似轮廓和已知的标度定律得到了很好的表征，但我们在这里表明，颗粒的简单存在会导致悬浮液以一种新的方式分解。使用高速成像，我们发现悬浮液滴的分离由幂律描述;具体地，我们发现颈部最小半径r（m），在时间τ = 0处接近破裂时的尺度如τ（2/3）。我们展示了各种颗粒/液体组合，包装分数，溶剂粘度和初始条件下的数据崩溃。我们认为，这种缩放是一个后果的粒子变形的颈部表面，从而创造一个压力，是由惯性平衡，并显示它是如何出现的拓扑约束，与宏观高斯曲率的粒子配置。这种新类型的缩放，独特的强制执行的几何形状和调节的颗粒，显示其初始条件的记忆，未能自相似，并在通用悬浮界面给出的压力的影响。
When a dense suspension is squeezed from a nozzle, droplet detachment can occur similar to that of pure liquids. While in pure liquids the process of droplet detachment is well characterized through self-similar profiles and known scaling laws, we show here the simple presence of particles causes suspensions to break up in a new fashion. Using high-speed imaging, we find that detachment of a suspension drop is described by a power law; specifically we find the neck minimum radius, r(m), scales like tau(2/3) near breakup at time tau = 0. We demonstrate data collapse in a variety of particle/liquid combinations, packing fractions, solvent viscosities, and initial conditions. We argue that this scaling is a consequence of particles deforming the neck surface, thereby creating a pressure that is balanced by inertia, and show how it emerges from topological constraints that relate particle configurations with macroscopic Gaussian curvature. This new type of scaling, uniquely enforced by geometry and regulated by the particles, displays memory of its initial conditions, fails to be self-similar, and has implications for the pressure given at generic suspension interfaces.