Nonmonotonic Diffusion in Sheared Active Suspensions of Squirmers
-
1.
University of British Columbia
-
2.
Royal Institute of Technology
-
3.
California Institute of Technology
Abstract
We investigate how shear influences the dynamics of active particles in dilute to concentrated suspensions. Using apolar active suspensions of squirmers as model systems, we show how their longtime diffusive dynamics can surprisingly slow down and vary nonmonotonically with the shear rate arising from an interplay between the activity-induced persistent motion and shear-induced reorientation and diffusion. Further simulations of self-propelled particles with tunable persistence exhibit richer dynamics and confirm the observed coupling, suggesting that nonmonotonic diffusion may be a general feature of fluids endowed with an underlying microstructure and large persistence. Our results reveal a nonlinear effect of shear on diffusion in active suspensions, elucidate how internal and external forcing interact, and provide new possibilities to modulate transport in active fluids.
Copyright and License
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by Bibsam.
Acknowledgement
We are grateful to Boyuan Chen for help in the code development and thank Eva Kanso, Tingtao Zhou, and the anonymous referees for useful comments. Z. G. acknowledges support from the Swedish Research Council under Grant No. 2021-06669VR.
Funding
Z. G. acknowledges support from the Swedish Research Council under Grant No. 2021-06669VR.
Data Availability
The data that support the findings of this article are openly available [58].
Supplemental Material
The supplemental files include a text description of our simulation method, setup and verification, supporting results mentioned in the main text, as well as two videos showing the shaker dynamics under three shear rates at 10% and 40% volume fractions, respectively.
Files
54qq-1s51.pdf
Additional details
Related works
- Is new version of
- Discussion Paper: arXiv:2505.09457 (arXiv)
- Is supplemented by
- Software: https://github.com/GeZhouyang/FSD (URL)
Funding
- Swedish Research Council
- 2021-06669VR
Dates
- Submitted
-
2025-05-13
- Accepted
-
2025-11-12
Caltech Custom Metadata
- Caltech groups
- Division of Chemistry and Chemical Engineering (CCE)
- Publication Status
- Published