Bacterial activity hinders particle sedimentation
Bacterial activity hinders particle sedimentation
复制标题
细菌活动阻碍颗粒沉降
DOI：
10.1039/d0sm02115f
复制
发表时间：
2021
期刊：
影响因子：
3.4
通讯作者：
Arratia, Paulo E.
中科院分区：
文献类型：
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作者：
Singh, Jaspreet;Patteson, Alison E.;Torres Maldonado, Bryan O.;Purohit, Prashant K.;Arratia, Paulo E.
由于游动微生物在自然和工业过程中的普遍存在，活性流体中的沉积已成为焦点。在这里，我们调查的沉降动力学的被动颗粒在流体中作为细菌E。大肠杆菌浓度。结果表明，游泳细菌的存在显着降低的沉降前的速度，即使在稀的制度，其中的沉降速度预计是独立的颗粒浓度。此外，细菌增加了被动颗粒的分散，这决定了沉降前沿的宽度。在短时间内，颗粒沉降速度与细菌浓度呈线性关系。然而，均方位移数据显示，细菌活性会随着较长的实验（沉降）时间而衰减。一个对流扩散方程耦合到细菌种群动态似乎捕捉浓度分布相对较好。单颗粒速度与细菌流速的比值可以作为预测前锋沉降速度的单一参数。
Sedimentation in active fluids has come into focus due to the ubiquity of swimming micro-organisms in natural and industrial processes. Here, we investigate sedimentation dynamics of passive particles in a fluid as a function of bacteria E. coli concentration. Results show that the presence of swimming bacteria significantly reduces the speed of the sedimentation front even in the dilute regime, in which the sedimentation speed is expected to be independent of particle concentration. Furthermore, bacteria increase the dispersion of the passive particles, which determines the width of the sedimentation front. For short times, particle sedimentation speed has a linear dependence on bacterial concentration. Mean square displacement data shows, however, that bacterial activity decays over long experimental (sedimentation) times. An advection-diffusion equation coupled to bacteria population dynamics seems to capture concentration profiles relatively well. A single parameter, the ratio of single particle speed to the bacteria flow speed can be used to predict front sedimentation speed.