Driven colloidal fluids: construction of dynamical density functional theories from exactly solvable limits
Driven colloidal fluids: construction of dynamical density functional theories from exactly solvable limits
复制标题
驱动胶体流体：从精确可解的极限构建动态密度泛函理论
DOI：
10.1088/0953-8984/28/24/244023
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
J. Brader
中科院分区：
文献类型：
--
作者：
A. Scacchi;M. Krüger;J. Brader
经典的动力学密度泛函理论(DDFT)提供了平衡密度泛函的近似推广，用于处理服从布朗动力学的非平衡系统。然而，当该方法应用于驱动系统时，例如剪切胶体分散体，该方法失败。DDFT的崩溃可以追溯到对对关联函数的流动引起的失真处理不当。通过考虑流量对关联到二阶的扭曲，我们展示了如何系统地校正被驱动系统的DDFT。作为我们方法的一个应用，我们考虑Poiseuille流。该理论预测，颗粒将聚集在局部剪切率较小的空间区域，这种效应被称为剪切诱导迁移。我们将这些预测与布朗动力学模拟进行了比较，结果基本一致。
The classical dynamical density functional theory (DDFT) provides an approximate extension of equilibrium DFT to treat nonequilibrium systems subject to Brownian dynamics. However, the method fails when applied to driven systems, such as sheared colloidal dispersions. The breakdown of DDFT can be traced back to an inadequate treatment of the flow-induced distortion of the pair correlation functions. By considering the distortion of the pair correlations to second order in the flow-rate we show how to systematically correct the DDFT for driven systems. As an application of our approach we consider Poiseuille flow. The theory predicts that the particles will accumulate in spatial regions where the local shear rate is small, an effect known as shear-induced migration. We compare these predictions to Brownian dynamics simulations with generally good agreement.