| Autor: |
Maldonado, Bryan O. Torres, Pradeep, Shravan, Ran, Ranjiangshang, Jerolmack, Douglas, Arratia, Paulo E. |
| Předmět: |
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| Zdroj: |
Journal of Fluid Mechanics; 6/10/2024, Vol. 988, p1-16, 16p |
| Abstrakt: |
Microorganisms are ubiquitous in nature and technology. They inhabit diverse environments, ranging from small river tributaries and lakes, to oceans, as well as wastewater treatment plants and food manufacturing. In many of these environments, microorganisms coexist with settling particles. Here, we investigate the effects of microbial activity (swimming E. coli) on the settling dynamics of passive colloidal particles using particle tracking methods. Our results reveal the existence of two distinct regimes in the correlation length scale (Lu) and the effective diffusivity of the colloidal particles (Deff), with increasing bacterial concentration (fb). At low fb, the parameters Lu and Deff increase monotonically with increasing fb. Beyond critical fb, a second regime is found where both Deff and Lu are independent of fb. We demonstrate that the transition between these regimes is characterized by the emergence of bioconvection. We use experimentally measured particle-scale quantities Lu and Deff to predict the critical bacterial concentration for the diffusion-bioconvection transition. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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