Multiscale modeling of particle in suspension with smoothed dissipative particle dynamics
Multiscale modeling of particle in suspension with smoothed dissipative particle dynamics
复制标题
DOI：
10.1063/1.3676244
复制
发表时间：
2012-01-01
影响因子：
4.6
通讯作者：
Adams, Nikolaus A.
中科院分区：
文献类型：
--
作者：
Bian, Xin;Litvinov, Sergey;Adams, Nikolaus A.
我们应用平滑耗散粒子动力学（SDPD）[Espanol 和 Revenga，Phys。 Rev. E 67, 026705 (2003)] 模拟悬浮液中的固体颗粒。 SDPD 是平滑粒子流体力学 (SPH) 的热力学一致版本，可以解释为将宏观 SPH 与介观耗散粒子动力学 (DPD) 方法联系起来的多尺度粒子框架。嵌入流体中的任意形状的刚性结构由冻结颗粒建模，在冻结颗粒上分配人工速度，以便精确满足固液界面上的无滑移边界条件。通过求解由周围液体施加的总阻力/扭矩导出的刚体平移/角速度的额外方程，将刚性结构的动力学与溶剂解耦。 SDPD 热波动与流体颗粒尺寸的正确缩放使我们能够描述颗粒悬浮液在空间尺度上的行为，范围从亚微米尺寸物体典型的扩散主导状态到表征宏观连续流条件的非布朗状态。该方法在布朗/非布朗环境中针对二维/三维散装颗粒系统的情况进行了广泛的测试，显示出数值收敛性以及与分析理论的良好一致性。最后，为了说明模型与外部边界几何形状耦合的能力，考虑了限制对微通道内单个球体扩散特性的影响，评估了扩散系数对壁分离距离的依赖性，并与可用的分析结果进行了比较。 (C) 2012 年美国物理研究所。 [号码：10.1063/1.3676244]
We apply smoothed dissipative particle dynamics (SDPD)[Espanol and Revenga, Phys. Rev. E 67, 026705 (2003)] to model solid particles in suspension. SDPD is a thermodynamically consistent version of smoothed particle hydrodynamics (SPH) and can be interpreted as a multiscale particle framework linking the macroscopic SPH to the mesoscopic dissipative particle dynamics (DPD) method. Rigid structures of arbitrary shape embedded in the fluid are modeled by frozen particles on which artificial velocities are assigned in order to satisfy exactly the no-slip boundary condition on the solid-liquid interface. The dynamics of the rigid structures is decoupled from the solvent by solving extra equations for the rigid body translational/angular velocities derived from the total drag/torque exerted by the surrounding liquid. The correct scaling of the SDPD thermal fluctuations with the fluid-particle size allows us to describe the behavior of the particle suspension on spatial scales ranging continuously from the diffusion-dominated regime typical of sub-micron-sized objects towards the non-Brownian regime characterizing macro-continuum flow conditions. Extensive tests of the method are performed for the case of two/three dimensional bulk particle-system both in Brownian/non-Brownian environment showing numerical convergence and excellent agreement with analytical theories. Finally, to illustrate the ability of the model to couple with external boundary geometries, the effect of confinement on the diffusional properties of a single sphere within a micro-channel is considered, and the dependence of the diffusion coefficient on the wall-separation distance is evaluated and compared with available analytical results. (C) 2012 American Institute of Physics. [doi :10.1063/1.3676244]