Anisotropic single-particle dissipative particle dynamics model

JOURNAL OF COMPUTATIONAL PHYSICS

卷:336

Article

Deng, Mingge¹  Pan, Wenxiao²  Karniadakis, George Em¹ 

[1] Brown Univ, Div Appl Math, Providence, RI 02912 USA

[2] Univ Wisconsin, Dept Mech Engn, Madison, WI 53706 USA

关键词: Dissipative particle dynamics;    Single-particle dissipative particle dynamics;    Colloid suspension;    Ellipsoidal particle;   

DOI  :  10.1016/j.jcp.2017.01.033

来源: Elsevier

【 摘 要 】

We have developed a new single-particle dissipative particle dynamics (DPD) model for anisotropic particles with different shapes, e.g., prolate or oblate spheroids. In particular, the conservative and dissipative interactions between anisotropic single DPD particles are formulated using a linear mapping from the isotropic model of spherical particles. The proper mapping operator is constructed between each interacting pair of particles at every time step. Correspondingly, the random forces are properly formulated to satisfy the fluctuation-dissipation theorem (FDT). Notably, the model exactly conserves both linear and angular momentum. We demonstrate the proposed model's accuracy and efficiency by applying it for modeling colloidal ellipsoids. Specifically, we show it efficiently captures the static properties of suspensions of colloidal ellipsoids. The isotropic-nematic transition in an ellipsoidal suspension is reproduced by increasing its volume fraction or the aspect ratio of ellipsoid particles. Moreover, the hydrodynamics and diffusion of a single colloidal ellipsoid (prolate or oblate with moderate aspect ratios) are accurately captured. The calculated drag force on the ellipsoid and its diffusion coefficients (both translational and rotational) agree quantitatively with the theoretical predictions in the Stokes limit. (C) 2017 Elsevier Inc. All rights reserved.

【 授权许可】

Free