论文标题
简单流体中剪切诱导的远程相关性的分子动力学研究
Molecular dynamics study of shear-induced long-range correlations in simple fluids
论文作者
论文摘要
我们研究了使用分子动力学（MD）仿真引起的剪切流诱导的远程相关性（LRC）。我们通过将MD结果与线性的波动流体动力学（LFH）进行比较来观察LRC。我们发现MD结果具有很大的有限尺寸效果，并且可以防止小型系统中LRC的发生。我们使用由超过一千万个颗粒组成的足够大的系统检查有限尺寸的效果，并验证剪切诱导的LRC的存在而没有歧义。此外，我们表明MD结果与大型系统的LFH解决方案在定量上是一致的。随着我们降低系统尺寸$ l $或增加剪切速率$ \dotγ$，流体动力描述逐渐在长波长区域中分解。 We define a characteristic wavenumber $k^{\rm vio}$ associated with the breakdown and find the nontrivial scaling relations $k^{\rm vio} \propto L^{-ω}$ and $k^{\rm vio} \propto \dotγ$, where $ω$ is an exponent depending on $\dotγ$.这些关系使我们能够在较小系统的大尺寸模拟中估算有限尺寸的效果。
We investigate long-range correlations (LRCs) induced by shear flow using the molecular dynamics (MD) simulation. We observe the LRCs by comparing the MD results with the linearized fluctuating hydrodynamics (LFH). We find that the MD result has large finite-size effects, and it prevents the occurrence of LRCs in small systems. We examine the finite-size effects using a sufficiently large system consisting of more than ten million particles, and verify the existence of shear-induced LRCs without ambiguity. Furthermore, we show that MD result is quantitatively consistent with the LFH solution for the large system. As we reduce the system size $L$ or increase the shear rate $\dotγ$, the hydrodynamic description gradually breaks down in the long-wavelength region. We define a characteristic wavenumber $k^{\rm vio}$ associated with the breakdown and find the nontrivial scaling relations $k^{\rm vio} \propto L^{-ω}$ and $k^{\rm vio} \propto \dotγ$, where $ω$ is an exponent depending on $\dotγ$. These relations enable us to estimate the finite-size effects in a larger-size simulation from a smaller system.
