Spontaneous Flows in Suspensions of Active Cyclic Swimmers
Spontaneous Flows in Suspensions of Active Cyclic Swimmers
复制标题
主动循环游泳者悬浮液中的自发流动
DOI：
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发表时间：
2015
影响因子：
3
通讯作者：
D. Saintillan
中科院分区：
文献类型：
--
作者：
Tommaso Brotto;D. Bartolo;D. Saintillan
许多游泳细胞依靠周期性变形来实现运动。在这项工作中，我们介绍了一个理论模型和数值模拟，以阐明这些周期性中风的影响，出现的中尺度结构和集体运动的游泳悬浮液。该模型扩展了以前的动力学理论的人口相同的游泳者的情况下，自推进的粒子之间的推和拉状态的过渡，并施加到量化的流体动力学速度场的不稳定性，每个游泳者人口的贡献，影响自发流动的发病和特征。线性稳定性分析表明，人口平均偶极子的符号确定的均匀各向同性状态的稳定性，与悬浮液为主的推杆受到不断增长的弯曲弯曲波动。然而，随机转换也被认为提供了额外的阻尼机制。为了研究不稳定阈值以上的人口动态，我们还进行了直接粒子模拟的基础上细长体模型，其中的游泳者所产生的有功功率的增长或衰减被发现是一个强大的结构和动力学不稳定性的措施。
Many swimming cells rely on periodic deformations to achieve locomotion. We introduce in this work a theoretical model and numerical simulations in order to elucidate the impact of these cyclic strokes on the emergence of mesoscale structures and collective motion in swimmer suspensions. The model extends previous kinetic theories for populations of identical swimmers to the case of self-propelled particles undergoing transitions between pusher and puller states, and is applied to quantify how the unsteadiness of the hydrodynamic velocity field, to which each swimmer population contributes, affects the onset and characteristics of spontaneous flows. A linear stability analysis reveals that the sign of the population-averaged dipole determines the stability of the uniform isotropic state, with suspensions dominated by pushers being subject to growing nematic bend fluctuations. Stochastic transitions, however, are also seen to provide an additional damping mechanism. To investigate the population dynamics above the instability threshold, we also perform direct particle simulations based on a slender-body model, where the growth or decay of the active power generated by the swimmers is found to be a robust measure of the structural and dynamical instability.
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影响因子：
44.1
作者：
Marchetti, M. C.;Joanny, J. F.;Simha, R. Aditi
通讯作者：
Simha, R. Aditi
绿藻作为生物流体动力学的模型生物。
影响因子：
27.7
作者：
Goldstein RE
通讯作者：
Goldstein RE
影响因子：
8.6
作者：
Drescher, Knut;Goldstein, Raymond E.;Tuval, Idan
通讯作者：
Tuval, Idan
影响因子：
8.6
作者：
Gao T;Blackwell R;Glaser MA;Betterton MD;Shelley MJ
通讯作者：
Shelley MJ