A hybrid multiscale dissipative particle dynamics method coupling particle and continuum for complex fluid
A hybrid multiscale dissipative particle dynamics method coupling particle and continuum for complex fluid
复制标题
DOI：
10.1007/s10404-015-1623-z
复制
发表时间：
2015-08
影响因子：
2.8
通讯作者：
Yanggui Li;Xingguo Geng;J. Ouyang;D. Zang;Xin Zhuang
中科院分区：
文献类型：
--
作者：
Yanggui Li;Xingguo Geng;J. Ouyang;D. Zang;Xin Zhuang
提出了一种模拟复杂流体的混合多尺度耗散粒子动力学(HMDPD)方法，其中中尺度流动采用耗散粒子动力学(DPD)，宏观流动采用连续介质N-S方程。特别是，为了克服有限元方法求解N-S方程的数值不稳定性，引入了变分多尺度方法。连续介质方程和DPD之间的空间耦合是通过重叠区域的约束动力学来实现的。通过对Couette流问题的仿真，验证了HMDPD方法的有效性。然后，将该方法应用于极稀聚合物溶液在Couette流动中的数值模拟。为了更准确地模拟聚合物稀溶液中的高分子链，我们建立了一个修正的有限伸缩非线性弹性链模型，该模型以一段的平衡长度为键长，较好地描述了相邻微珠之间的弹性拉力和弹性斥力。结果表明，使用HMDPD方法不仅可以计算宏观流动速度，而且可以观察到剪切流场影响下高分子链的构象变化和动力学行为等介观分子细节。
A hybrid multiscale dissipative particle dynamics (HMDPD) method is proposed for simulating complex fluid, in which dissipative particle dynamics (DPD) is used in the mesoscale flow region and continuum Navier–Stokes equations in the macroscale one. In particular, the variational multiscale method is introduced to overcome the numerical instabilities of the finite element method for solving the Navier–Stokes equations. The spatial coupling between continuum equations and DPD is achieved through constrained dynamics in an overlap region. The Couette flow problem is simulated to verify the proposed HMDPD method. Then, the method is applied to simulate extremely dilute polymer solution in Couette flow. In order to more accurately imitate the polymer chain in the dilute polymer solution, we develop a modified finitely extensible nonlinear elastic chain model, which perfectly describes both the elastic tension and the elastic repulsion between the adjacent beads with bond length as the equilibrium length of one segment. It is found that, using the proposed HMDPD method, not only the macroscopic flow velocity can be calculated, but also the mesoscopic molecular details such as conformational changes as well as dynamic behaviors of polymer chain under the influence of shear flow field can be observed.