Pair dispersion in dilute suspension of active swimmers
Ensembles of biological and artificial microswimmers produce long-range velocity fields with strong nonequilibrium fluctuations, which result in a dramatic increase in diffusivity of embedded particles (tracers). While such enhanced diffusivity may point to enhanced mixing of the fluid, a rigorous q...
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| Format: | Article |
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American Institute of Physics (AIP)
2019
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| Online Access: | https://hdl.handle.net/1721.1/121455 |
| _version_ | 1811080159378276352 |
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| author | Belan, Sergey Kardar, Mehran |
| author2 | Massachusetts Institute of Technology. Department of Physics |
| author_facet | Massachusetts Institute of Technology. Department of Physics Belan, Sergey Kardar, Mehran |
| author_sort | Belan, Sergey |
| collection | MIT |
| description | Ensembles of biological and artificial microswimmers produce long-range velocity fields with strong nonequilibrium fluctuations, which result in a dramatic increase in diffusivity of embedded particles (tracers). While such enhanced diffusivity may point to enhanced mixing of the fluid, a rigorous quantification of the mixing efficiency requires analysis of pair dispersion of tracers, rather than simple one-particle diffusivity. Here, we calculate analytically the scale-dependent coefficient of relative diffusivity of passive tracers embedded in a dilute suspension of run-and-tumble microswimmers. Although each tracer is subject to strong fluctuations resulting in large absolute diffusivity, the small-scale relative dispersion is suppressed due to the correlations in fluid velocity which are relevant when the inter-tracer separation is below the persistence length of the swimmer's motion. Our results suggest that the reorientation of swimming direction plays an important role in biological mixing and should be accounted in the design of potential active matter devices capable of effective fluid mixing at microscale. |
| first_indexed | 2024-09-23T11:26:48Z |
| format | Article |
| id | mit-1721.1/121455 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T11:26:48Z |
| publishDate | 2019 |
| publisher | American Institute of Physics (AIP) |
| record_format | dspace |
| spelling | mit-1721.1/1214552022-10-01T03:42:23Z Pair dispersion in dilute suspension of active swimmers Belan, Sergey Kardar, Mehran Massachusetts Institute of Technology. Department of Physics Ensembles of biological and artificial microswimmers produce long-range velocity fields with strong nonequilibrium fluctuations, which result in a dramatic increase in diffusivity of embedded particles (tracers). While such enhanced diffusivity may point to enhanced mixing of the fluid, a rigorous quantification of the mixing efficiency requires analysis of pair dispersion of tracers, rather than simple one-particle diffusivity. Here, we calculate analytically the scale-dependent coefficient of relative diffusivity of passive tracers embedded in a dilute suspension of run-and-tumble microswimmers. Although each tracer is subject to strong fluctuations resulting in large absolute diffusivity, the small-scale relative dispersion is suppressed due to the correlations in fluid velocity which are relevant when the inter-tracer separation is below the persistence length of the swimmer's motion. Our results suggest that the reorientation of swimming direction plays an important role in biological mixing and should be accounted in the design of potential active matter devices capable of effective fluid mixing at microscale. 2019-06-28T16:46:19Z 2019-06-28T16:46:19Z 2019-02 2018-11 2019-03-28T19:49:50Z Article http://purl.org/eprint/type/JournalArticle 0021-9606 1089-7690 https://hdl.handle.net/1721.1/121455 Belan, Sergey and Mehran Kardar. “Pair Dispersion in Dilute Suspension of Active Swimmers.” The Journal of Chemical Physics 150, 6 (February 2019): 064907 © 2019 Author(s) http://dx.doi.org/10.1063/1.5081006 Journal of Chemical Physics Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf American Institute of Physics (AIP) arXiv |
| spellingShingle | Belan, Sergey Kardar, Mehran Pair dispersion in dilute suspension of active swimmers |
| title | Pair dispersion in dilute suspension of active swimmers |
| title_full | Pair dispersion in dilute suspension of active swimmers |
| title_fullStr | Pair dispersion in dilute suspension of active swimmers |
| title_full_unstemmed | Pair dispersion in dilute suspension of active swimmers |
| title_short | Pair dispersion in dilute suspension of active swimmers |
| title_sort | pair dispersion in dilute suspension of active swimmers |
| url | https://hdl.handle.net/1721.1/121455 |
| work_keys_str_mv | AT belansergey pairdispersionindilutesuspensionofactiveswimmers AT kardarmehran pairdispersionindilutesuspensionofactiveswimmers |