Particle-based simulations of self-motile suspensions

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• 作者：Denis F. Hinz^a ; ^{dfh@kamstrup.com" class="auth_mail" title="E-mail the corresponding author} ; Alexander Panchenko^b ; ^{panchenko@math.wsu.edu" class="auth_mail" title="E-mail the corresponding author} ; Tae-Yeon Kim^c ; ^{taeyeon.kim@kustar.ac.ae" class="auth_mail" title="E-mail the corresponding author} ; Eliot Fried^d ; ^{eliot.fried@oist.jp" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Dissipative particle dynamics ; Bacterial suspensions ; Hydrodynamic interactions ; Two-dimensional turbulence ; Upscale energy transfer ; Integral length scale
• 刊名：Computer Physics Communications
• 出版年：2015
• 出版时间：November 2015
• 年：2015
• 卷：196
• 期：Complete
• 页码：45-57
• 全文大小：2336 K

文摘

A simple model for simulating flows of active suspensions is investigated. The approach is based on dissipative particle dynamics. While the model is potentially applicable to a wide range of self-propelled particle systems, the specific class of self-motile bacterial suspensions is considered as a modeling scenario. To mimic the rod-like geometry of a bacterium, two dissipative particle dynamics particles are connected by a stiff harmonic spring to form an aggregate dissipative particle dynamics molecule. Bacterial motility is modeled through a constant self-propulsion force applied along the axis of each such aggregate molecule. The model accounts for hydrodynamic interactions between self-propelled agents through the pairwise dissipative interactions conventional to dissipative particle dynamics. Numerical simulations are performed using a customized version of the open-source software package LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) software package. Detailed studies of the influence of agent concentration, pairwise dissipative interactions, and Stokes friction on the statistics of the system are provided. The simulations are used to explore the influence of hydrodynamic interactions in active suspensions. For high agent concentrations in combination with dominating pairwise dissipative forces, strongly correlated motion patterns and a fluid-like spectral distributions of kinetic energy are found. In contrast, systems dominated by Stokes friction exhibit weaker spatial correlations of the velocity field. These results indicate that hydrodynamic interactions may play an important role in the formation of spatially extended structures in active suspensions.