Snapping elastic disks as microswimmers: swimming at low Reynolds numbers by shape hysteresis
| Autor: | Wischnewski, Christian, Kierfeld, Jan |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Soft Matter 16, 7088-7102 (2020) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1039/D0SM00741B |
| Popis: | We illustrate a concept for shape-changing microswimmers, which exploits the hysteresis of a shape transition of an elastic object, by an elastic disk undergoing cyclic localized swelling. Driving the control parameter of a hysteretic shape transition in a completely time-reversible manner gives rise to a non-time-reversible shape sequence and a net swimming motion if the elastic object is immersed into a viscous fluid. We prove this concept with a microswimmer which is a flat circular elastic disk that undergoes a transition into a dome-like shape by localized swelling of an inner disk. The control parameter of this shape transition is a scalar swelling factor of the disk material. With a fixed outer frame with an additional attractive interaction in the central region, the shape transition between flat and dome-like shape becomes hysteretic and resembles a hysteretic opening and closing of a scallop. Employing Stokesian dynamics simulations of a discretized version of the disk we show that the swimmer is effectively moving into the direction of the opening of the dome in a viscous fluid if the swelling parameter is changed in a time-reversible manner. The swimming mechanism can be qualitatively reproduced by a simple 9-bead model. Comment: 16 pages, 14 figures |
| Databáze: | arXiv |
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