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arXiv · 2006.08282

Lord Kelvin's isotropic helicoid

Darci Collins·Rami J. Hamati·Fabien Candelier·Kristian Gustavsson·Bernhard Mehlig·Greg A. Voth
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Abstract

Nearly 150 years ago, Lord Kelvin proposed the isotropic helicoid, a particle with isotropic yet chiral interactions with a fluid, so that translation couples to rotation. An implementation of his design fabricated with a three-dimensional printer is found experimentally to have no detectable translation-rotation coupling, although the particle point-group symmetry allows this coupling. We explain these results by demonstrating that in Stokes flow, the chiral coupling of such isotropic helicoids made out of non-chiral vanes is due only to hydrodynamic interactions between these vanes. Therefore it is small. In summary, Kelvin's predicted isotropic helicoid exists, but only as a weak breaking of a symmetry of non-interacting vanes in Stokes flow.

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Darci Collins, Rami J. Hamati, Fabien Candelier, Kristian Gustavsson, Bernhard Mehlig, Greg A. Voth. 2021-07-21. Lord Kelvin's isotropic helicoid. https://doi.org/10.1103/physrevfluids.6.074302

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