Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Penglais Campus, Aberystwyth, Ceredigion, Wales, SY23 3DA, United Kingdom.
Institute of Mathematics, Physics and Computer Science, Aberystwyth University, Penglais Campus, Aberystwyth, Ceredigion, Wales, SY23 3DB, United Kingdom.
Phys Rev E. 2019 Feb;99(2-1):022602. doi: 10.1103/PhysRevE.99.022602.
Active swarms, consisting of individual agents which consume energy to move or produce work, are known to generate a diverse range of collective behaviors. Many examples of active swarms are biological in nature (e.g., fish shoals and bird flocks) and have been modeled extensively by numerical simulations. Such simulations of swarms usually assume that the swarm is homogeneous; that is, every agent has exactly the same dynamical properties. However, many biological swarms are highly heterogeneous, such as multispecies communities of micro-organisms in soil, and individual species may have a wide range of different physical properties. Here we explore heterogeneity by developing a simple model for the dynamics of a swarm of motile heterogeneous rodlike bacteria in the absence of hydrodynamic effects. Using molecular dynamics simulations of active rods confined within a two-dimensional rectangular channel, we first explore the case of homogeneous swarms and show that the key parameter governing both dynamics is ratio of the motility force to the steric force. Next we explore heterogeneous or mixed swarms in which the constituent self-propelled rods have a range of motilities and steric interactions. Our results show that the confining boundaries play a strong role in driving the segregation of mixed populations.
由消耗能量来移动或产生功的个体组成的主动群体，被认为会产生多种不同的集体行为。许多主动群体的例子都是生物性质的（例如，鱼群和鸟群），并且已经通过数值模拟进行了广泛的建模。这种对群体的模拟通常假设群体是同质的；也就是说，每个个体都具有完全相同的动力学特性。然而，许多生物群体是高度异质的，例如土壤中微生物的多物种群落，并且个体物种可能具有广泛的不同物理特性。在这里，我们通过开发一个简单的模型来探索这种异质性，该模型用于研究无流体动力效应时的运动异质棒状细菌群体的动力学。我们使用二维矩形通道内受限的活性棒的分子动力学模拟，首先探索了同质群体的情况，并表明控制动力学的关键参数是运动力与空间力的比值。接下来，我们研究了异质或混合群体，其中组成的自主推进棒具有一系列的运动性和空间相互作用。我们的结果表明，限制边界在驱动混合群体的分离方面起着重要作用。
