Bacteria hinder large-scale transport and enhance small-scale mixing in time-periodic flows
Bacteria hinder large-scale transport and enhance small-scale mixing in time-periodic flows
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细菌阻碍大规模运输并增强时间周期流动中的小规模混合
DOI：
10.1073/pnas.2108548118
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Arratia, Paulo E.
中科院分区：
文献类型：
--
作者：
Ran, Ranjiangshang;Brosseau, Quentin;Blackwell, Brendan C.;Qin, Boyang;Winter, Rebecca L.;Arratia, Paulo E.
了解被动标量在主动流体中的混合和输运对许多自然（例如，藻华）和工业（例如，生物燃料、疫苗生产）过程。在这里，我们研究了混合的被动标量（染料）在稀释的悬浮液中swimmingEscherichia coli实验使用二维（2D）的时间周期流，并在一个简单的模拟。结果表明，细菌的存在阻碍了大规模的运输，降低了整体混合率。拉伸场，从实验测得的速度场计算，表明细菌活动衰减流体拉伸和降低流动混沌。模拟表明，这种衰减可能归因于细菌沿高拉伸沿着区域的瞬时积累。染料浓度场的空间功率谱和相关函数表明，跨尺度的标量方差的运输也受到细菌活动的阻碍，导致结构的平均尺寸和寿命的增加。另一方面，在小尺度上，活动似乎增强了局部混合。一个证据是，空间浓度梯度的概率分布几乎是对称的，偏度为零。总体而言，我们的研究结果表明，活动和流量之间的耦合可以导致非平凡的混合和运输的影响。
Understanding mixing and transport of passive scalars in active fluids is important to many natural (e.g., algal blooms) and industrial (e.g., biofuel, vaccine production) processes. Here, we study the mixing of a passive scalar (dye) in dilute suspensions of swimmingEscherichia coliin experiments using a two-dimensional (2D) time-periodic flow and in a simple simulation. Results show that the presence of bacteria hinders large-scale transport and reduces overall mixing rate. Stretching fields, calculated from experimentally measured velocity fields, show that bacterial activity attenuates fluid stretching and lowers flow chaoticity. Simulations suggest that this attenuation may be attributed to a transient accumulation of bacteria along regions of high stretching. Spatial power spectra and correlation functions of dye-concentration fields show that the transport of scalar variance across scales is also hindered by bacterial activity, resulting in an increase in average size and lifetime of structures. On the other hand, at small scales, activity seems to enhance local mixing. One piece of evidence is that the probability distribution of the spatial concentration gradients is nearly symmetric with a vanishing skewness. Overall, our results show that the coupling between activity and flow can lead to nontrivial effects on mixing and transport.
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DOI：
--
发表时间：
2001
期刊：
影响因子：
--
作者：
G. Voth;G. Haller;J. Gollub
通讯作者：
J. Gollub
影响因子：
8.6
作者：
Hill, Jane;Kalkanci, Ozge;Koser, Hur
通讯作者：
Koser, Hur
影响因子：
4.6
作者：
Benjamin S. Williams;D. Marteau;J. Gollub
通讯作者：
J. Gollub
DOI：
10.1073/pnas.1819613116
发表时间：
2019-06-04
影响因子：
11.1
作者：
Dehkharghani, Amin;Waisbord, Nicolas;Guasto, Jeffrey S.
通讯作者：
Guasto, Jeffrey S.
KCl 替代对大肠杆菌 (ATCC 25922) 和选定益生菌细菌活力的影响。
影响因子：
3.5
作者：
A. Gandhi;Yuxiang Cui;M. Zhou;N. Shah
通讯作者：
N. Shah