Hybrid molecular-continuum simulations using smoothed dissipative particle dynamics.
Hybrid molecular-continuum simulations using smoothed dissipative particle dynamics.
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DOI：
10.1063/1.4905720
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发表时间：
2015-01
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影响因子：
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通讯作者：
Nikolai D. Petsev;L. Leal;M. S. Shell
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文献类型：
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作者：
Nikolai D. Petsev;L. Leal;M. S. Shell
本文提出了一种新的多尺度模拟方法，用于将分子动力学（MD）模拟的具有原子细节的区域与光滑耗散粒子动力学（SDPD）得到的波动Navier-Stokes方程的数值解耦合起来。在这种方法中，化学势梯度是由于整个系统内的分辨率差异而产生的，并通过在两个区域之间的缓冲区内引入成对的热动力而减小，其中颗粒从MD类型转变为SDPD类型。当与Kulkarni等人提出的多分辨率SDPD方法相结合时[J]。化学。物理学报，138,234105(2013)]，该方法可以将原子模型系统地耦合到任意粗连续域上，这些域被建模为不同分辨率的SDPD流体。我们对该技术进行了测试，证明它正确地再现了简单Lennard-Jones流体的整个模拟域的热力学性质。此外，通过对剪切流启动的模拟，我们证明了该方法也适用于非平衡问题。用两种不同的流动情况说明了该方法的鲁棒性，在两种不同的流动情况下，剪切力在分离连续体和原子域的界面平行和垂直方向上作用。在这两种情况下，我们都得到了正确的瞬态速度剖面。我们还进行了三尺度剪切流模拟，其中我们包括两个不同分辨率的SDPD区域以及一个MD域，说明了三尺度耦合的可行性。
We present a new multiscale simulation methodology for coupling a region with atomistic detail simulated via molecular dynamics (MD) to a numerical solution of the fluctuating Navier-Stokes equations obtained from smoothed dissipative particle dynamics (SDPD). In this approach, chemical potential gradients emerge due to differences in resolution within the total system and are reduced by introducing a pairwise thermodynamic force inside the buffer region between the two domains where particles change from MD to SDPD types. When combined with a multi-resolution SDPD approach, such as the one proposed by Kulkarni et al. [J. Chem. Phys. 138, 234105 (2013)], this method makes it possible to systematically couple atomistic models to arbitrarily coarse continuum domains modeled as SDPD fluids with varying resolution. We test this technique by showing that it correctly reproduces thermodynamic properties across the entire simulation domain for a simple Lennard-Jones fluid. Furthermore, we demonstrate that this approach is also suitable for non-equilibrium problems by applying it to simulations of the start up of shear flow. The robustness of the method is illustrated with two different flow scenarios in which shear forces act in directions parallel and perpendicular to the interface separating the continuum and atomistic domains. In both cases, we obtain the correct transient velocity profile. We also perform a triple-scale shear flow simulation where we include two SDPD regions with different resolutions in addition to a MD domain, illustrating the feasibility of a three-scale coupling.