Hansen J S, Daivis Peter J, Todd B D
Centre for Molecular Simulation, Swinburne University of Technology, Hawthorn, Victoria, Australia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Oct;80(4 Pt 2):046322. doi: 10.1103/PhysRevE.80.046322. Epub 2009 Oct 28.
In this paper we present equilibrium molecular-dynamics results for the shear, rotational, and spin viscosities for fluids composed of linear molecules. The density dependence of the shear viscosity follows a stretched exponential function, whereas the rotational viscosity and the spin viscosities show approximately power-law dependencies. The frequency-dependent shear and spin viscosities are also studied. It is found that viscoelastic behavior is first manifested in the shear viscosity and that the real part of the spin viscosities features a maximum for nonzero frequency. The calculated transport coefficients are used together with the extended Navier-Stokes equations to investigate the effect of the coupling between the intrinsic angular momentum and linear momentum for highly confined fluids. Both steady and oscillatory flows are studied. It is shown, for example, that the fluid flow rate for Poiseuille flow is reduced by up to 10% in a 2 nm channel for a buta-triene fluid at density 236 kg m(-3) and temperature 306 K. The coupling effect may, therefore, become very important for nanofluidic applications.
在本文中，我们给出了由线性分子组成的流体的剪切黏度、转动黏度和自旋黏度的平衡分子动力学结果。剪切黏度的密度依赖性遵循拉伸指数函数，而转动黏度和自旋黏度则呈现出近似幂律依赖性。我们还研究了频率依赖的剪切黏度和自旋黏度。结果发现，黏弹性行为首先在剪切黏度中表现出来，并且自旋黏度的实部在非零频率处出现最大值。计算得到的输运系数与扩展的纳维-斯托克斯方程一起用于研究高度受限流体中固有角动量和线性动量之间耦合的影响。我们研究了稳态流动和振荡流动。例如，结果表明，对于密度为236 kg m⁻³、温度为306 K的丁三烯流体，在2 nm的通道中泊肃叶流动的流体流速降低了高达10%。因此，这种耦合效应对于纳米流体应用可能变得非常重要。
