| Autor: |
Felix Rühle, Johannes Blaschke, Jan-Timm Kuhr, Holger Stark |
| Jazyk: |
angličtina |
| Rok vydání: |
2018 |
| Předmět: |
|
| Zdroj: |
New Journal of Physics, Vol 20, Iss 2, p 025003 (2018) |
| Druh dokumentu: |
article |
| ISSN: |
1367-2630 |
| DOI: |
10.1088/1367-2630/aa9ed3 |
| Popis: |
We perform hydrodynamic simulations using the method of multi-particle collision dynamics and a theoretical analysis to study a single squirmer microswimmer at high Péclet number, which moves in a low Reynolds number fluid and under gravity. The relevant parameters are the ratio α of swimming to bulk sedimentation velocity and the squirmer type β . The combination of self-propulsion, gravitational force, hydrodynamic interactions with the wall, and thermal noise leads to a surprisingly diverse behavior. At $\alpha \gt 1$ we observe cruising states, while for $\alpha \lt 1$ the squirmer resides close to the bottom wall with the motional state determined by stable fixed points in height and orientation. They strongly depend on the squirmer type β . While neutral squirmers permanently float above the wall with upright orientation, pullers float for α larger than a threshold value ${\alpha }_{\mathrm{th}}$ and are pinned to the wall below ${\alpha }_{\mathrm{th}}$ . In contrast, pushers slide along the wall at lower heights, from which thermal orientational fluctuations drive them into a recurrent floating state with upright orientation, where they remain on the timescale of orientational persistence. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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