Smoothed dissipative particle dynamics with angular momentum conservation
Smoothed dissipative particle dynamics with angular momentum conservation
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DOI：
10.1016/j.jcp.2014.10.017
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发表时间：
2015-01-15
影响因子：
4.1
通讯作者：
Gompper, Gerhard
中科院分区：
文献类型：
--
作者：
Mueller, Kathrin;Fedosov, Dmitry A.;Gompper, Gerhard
光滑耗散粒子动力学(SDPD)结合了光滑粒子流体力学和耗散粒子动力学(DPD)这两种流行的介观方法，是一种改进的耗散粒子动力学方法。尽管SDPD方法比传统的DPD模型有许多优点，但Espano和Revenga(2003)[9]最初的SDPD公式缺乏角动量守恒，导致在角动量守恒必不可少的问题上产生非物理结果。为了克服这一局限性，我们通过引入粒子自旋变量来扩展SDPD方法，从而恢复局部和整体角动量守恒。新的SDPD公式(SDPD+a)直接从含自旋流体的Navier-Stokes方程导出，而热涨落与DPD方法类似。我们测试了新的SDPD方法，并证明它正确地再现了流体输运系数。用两个问题验证了具有角动量守恒的SDPD：(I)具有两个不相容流体的Taylor-Couette流；(Ii)具有内外流体粘性差的剪切流中的槽形气泡。对于这两个问题，新的SDPD方法得到了与相应的解析理论相一致的模拟预测，而原有的SDPD方法由于违反了角动量守恒而未能正确地捕捉到系统的物理特征。总之，具有角动量守恒的扩展SDPD方法为处理多相流和囊泡/细胞悬浮液等流体问题提供了一种新的途径，在这些问题中角动量守恒是必不可少的。(C)2014 Elsevier Inc.保留所有权利。
Smoothed dissipative particle dynamics (SDPD) combines two popular mesoscopic techniques, the smoothed particle hydrodynamics and dissipative particle dynamics (DPD) methods, and can be considered as an improved dissipative particle dynamics approach. Despite several advantages of the SDPD method over the conventional DPD model, the original formulation of SDPD by Espanol and Revenga (2003) [9], lacks angular momentum conservation, leading to unphysical results for problems where the conservation of angular momentum is essential. To overcome this limitation, we extend the SDPD method by introducing a particle spin variable such that local and global angular momentum conservation is restored. The new SDPD formulation (SDPD+a) is directly derived from the Navier-Stokes equation for fluids with spin, while thermal fluctuations are incorporated similarly to the DPD method. We test the new SDPD method and demonstrate that it properly reproduces fluid transport coefficients. Also, SDPD with angular momentum conservation is validated using two problems: (i) the Taylor-Couette flow with two immiscible fluids and (ii) a tank-treading vesicle in shear flow with a viscosity contrast between inner and outer fluids. For both problems, the new SDPD method leads to simulation predictions in agreement with the corresponding analytical theories, while the original SDPD method fails to capture properly physical characteristics of the systems due to violation of angular momentum conservation. In conclusion, the extended SDPD method with angular momentum conservation provides a new approach to tackle fluid problems such as multiphase flows and vesicle/cell suspensions, where the conservation of angular momentum is essential. (C) 2014 Elsevier Inc. All rights reserved.