The autophoretic torus
arXiv:1702.00574
Abstract
Phoretic swimmers provide new avenues to study non-equilibrium statistical physics and are also hailed as a promising technology for bioengineering at the cellular scale. Exact solutions for the locomotion of such swimmers have been restricted so far to spheroidal shapes. In this paper we solve for the flow induced by the canonical non-simply connected shape, namely an axisymmetric phoretic torus. The analytical solution takes the form of an infinite series solution, which we validate against boundary element computations. For a torus of uniform chemical activity, confinement effects in the hole allow the torus to act as a pump, which we optimize subject to fixed particle surface area. Under the same constraint, we next characterize the fastest swimming Janus torus for a variety of assumptions on the surface chemistry. Perhaps surprisingly, none of the optimal tori occur in the limit where the central hole vanishes.
13 pages, 8 figures
References in corpus (6)
- Self-motile colloidal particles: from directed propulsion to random walk
- Propulsion of a molecular machine by asymmetric distribution of reaction--products
- Phoretic Motion of Spheroidal Particles Due To Self-Generated Solute Gradients
- Autophoretic locomotion from geometric asymmetry
- Surface tank-treading: propulsion of Purcell's toroidal swimmer
- The other optimal Stokes drag profile