Helicity Decay in Vortex Rings
ORAL
Abstract
The helicity of vortex loops is captured in the loops' linking, writhe, and twist. In viscous fluids, helicity loses its conserved status and is dissipated through only one of these modes -- twist. By generating helical vortices using hydrofoils, we are able to measure their helicity and its decay over a range of viscosities. We report the dissipation and exchange dynamics and interpret them in terms of the evolution of the vortex core geometry and size, which we resolve using a novel method.
*This work was funded by U.S. NSF grant DMR-1351506 and Army Research Office grant W911NF-18-1-0046. Additional support was provided by the Chicago MRSEC (U.S. NSF grant DMR 1420709), which is also gratefully acknowledged for access to its shared experimental facilities.
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Presenters
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Robert Morton
- James Franck Institute, University of Chicago