Magnetoviscosity of semidilute ferrofluids and the role of dipolar interactions: comparison of molecular simulations and dynamical mean-field theory.
Magnetoviscosity of semidilute ferrofluids and the role of dipolar interactions: comparison of molecular simulations and dynamical mean-field theory.
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DOI：
10.1103/physreve.71.031205
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发表时间：
2005-03
期刊：
影响因子：
--
通讯作者：
P. Ilg;M. Kröger;S. Hess
中科院分区：
文献类型：
--
作者：
P. Ilg;M. Kröger;S. Hess
为了研究半稀磁流体中的磁粘性和粘弹性现象，对模型磁流体进行了广泛的分子模拟。给出了非平衡磁化强度、剪切粘度和法向应力差的模拟结果。分析了转动和构型对剪切粘度的贡献，并讨论了它们对磁粘性效应的影响。非相互作用磁偶极子的简化模型描述了非平衡磁化强度和转动粘性，但没有考虑位形粘滞贡献和法向应力差。改进的平均场模型克服了这些限制，对弱偶极子相互作用的模拟结果与模型应该应用的地方的模拟结果吻合得很好。通过与不同相互作用强度的模拟结果的比较，我们可以确定平均场模型的有效范围。
Extensive molecular simulations on a model ferrofluid are performed in order to study magnetoviscous and viscoelastic phenomena in semidilute ferrofluids. Simulation results of the nonequilibrium magnetization, shear viscosity, and normal stress differences are presented. Rotational and configurational contributions to the shear viscosity are analyzed and their influence on the magnetoviscous effect is discussed. The simplified model of noninteracting magnetic dipoles describes the nonequilibrium magnetization and the rotational viscosity, but does not account for configurational viscosity contributions and normal stress differences. Improved mean-field models that overcome these limitations show good agreement with the simulation results for weak dipolar interactions where the models should apply. Comparisons to simulation results for various interaction strengths allow us to determine the range of validity of the mean-field models.