A hydrodynamic model for discontinuous shear-thickening in dense suspensions
A hydrodynamic model for discontinuous shear-thickening in dense suspensions
复制标题
稠密悬浮液中不连续剪切增稠的流体动力学模型
DOI：
10.1122/1.5134036
复制
发表时间：
2020
影响因子：
3.3
通讯作者：
J. Brady
中科院分区：
文献类型：
--
作者：
Mu Wang;S. Jamali;J. Brady
胶体颗粒的受限滑动或旋转运动在不连续剪切增稠（DST）的出现中起着关键作用。从粘度函数到施加变形下的接触邻居的数量，对滑动运动的阻碍显着改变了所有尺度上的稠密悬浮液的行为。在这项工作中，隐式地通过使用修改后的流体动力学模型的基础上斯托克斯动力学和明确地通过解决非光滑胶体的流体动力学，我们表明，润滑力，从表面粗糙有效地提供了这样的约束切向粒子运动。观察到从连续剪切增稠到DST的过渡，因为颗粒的表面粗糙度系统地增加。在这个DST流体力学模型中，法向应力差在剪切增稠状态（STS）中保持为负。空间应力分布的研究表明，DST的发病是一个高度本地化的事件，然而，粒子自扩散和微观结构的网络建议在STS一个相当均匀的结构。
Restricted sliding or rotational motion of colloidal particles plays a key role in the emergence of discontinuous shear thickening (DST). From viscometric functions to the number of contacting neighbors under an applied deformation, a hindrance to sliding motion significantly changes the behavior of dense suspensions on all scales. In this work, implicitly by using a modified hydrodynamic model based on Stokesian dynamics and explicitly by solving for the hydrodynamics of nonsmooth colloids, we show that lubrication forces that arise from surface asperities effectively provide such constraints to tangential particle motion. A transition from continuous shear thickening to DST is observed as the surface roughness of the particles is systematically increased. In this hydrodynamic model for DST, normal stress differences remain negative in the shear-thickened state (STS). Study of the spatial stress distribution indicates the onset of DST to be a highly localized event; however, particle self-diffusivity and the microstructural network suggest a rather uniform structure in the STS.