Microscopic Origin of Frictional Rheology in Dense Suspensions: Correlations in Force Space.
Microscopic Origin of Frictional Rheology in Dense Suspensions: Correlations in Force Space.
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致密悬浮液中摩擦流变学的微观起源：力空间中的相关性。
DOI：
10.1103/physrevlett.121.128002
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发表时间：
2018
影响因子：
8.6
通讯作者：
B. Chakraborty
中科院分区：
文献类型：
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作者：
Jetin E. Thomas;K. Ramola;Abhinendra Singh;R. Mari;J. Morris;B. Chakraborty
我们基于表示力的空间中的相关性（与位置空间对偶），开发了用于致密非布朗悬浮液流变学的统计框架。利用二维悬浮液模拟获得的稳态构型系综，我们发现力空间中成对相关函数的各向异性随着围限剪切应力 (σ_{xy}) 和堆积分数 (phi) 的变化而变化。利用这些微观相关性，我们建立了宏观摩擦系数的统计理论：应力张量的各向异性，μ=σ_{xy}/P。我们发现，(i) 随着 phi 的增加，μ 减小，(ii) 随着 σ_{xy} 的增加，μ 减小。使用稠密悬浮液的 μ 和粘度之间的新本构关系（推广了与速率无关的关系），我们表明我们的理论预测了与数值模拟非常一致的不连续剪切增稠流动图，以及导致实验中观察到的不连续剪切增稠流体的通用流动图的 μ 的定性特征。
We develop a statistical framework for the rheology of dense, non-Brownian suspensions, based on correlations in a space representing forces, which is dual to position space. Working with the ensemble of steady state configurations obtained from simulations of suspensions in two dimensions, we find that the anisotropy of the pair correlation function in force space changes with confining shear stress (σ_{xy}) and packing fraction (ϕ). Using these microscopic correlations, we build a statistical theory for the macroscopic friction coefficient: the anisotropy of the stress tensor, μ=σ_{xy}/P. We find that μ decreases (i) as ϕ is increased and (ii) as σ_{xy} is increased. Using a new constitutive relation between μ and viscosity for dense suspensions that generalizes the rate-independent one, we show that our theory predicts a discontinuous shear thickening flow diagram that is in good agreement with numerical simulations, and the qualitative features of μ that lead to the generic flow diagram of a discontinuous shear thickening fluid observed in experiments.