Passive directors in turbulence
arXiv:1707.06037 · doi:10.1103/PhysRevFluids.4.054602
Abstract
In experiments and numerical simulations we measured angles between the symmetry axes of small spheroids advected in turbulence ("passive directors"). Since turbulent strains tend to align nearby spheroids, one might think that their relative angles are quite small. We show that this intuition fails in general because angles between the symmetry axes of nearby particles are anomalously large. We identify two mechanisms that cause this phenomenon. First, the dynamics evolves to a fractal attractor despite the fact that the fluid velocity is spatially smooth at small scales. Second, this fractal forms steps akin to scar lines observed in the director patterns for random or chaotic two-dimensional maps.
16 pages, 7 figures, revised version
References in corpus (8)
- Burgers Turbulence
- Rotation Rate of Rods in Turbulent Fluid Flow
- Caustic activation of rain showers
- Measurements of the coupling between the tumbling of rods and the velocity gradient tensor in turbulence
- Preferential sampling and small-scale clustering of gyrotactic microswimmers in turbulence
- Time-symmetry breaking in turbulence
- Angular dynamics of a small particle in turbulence
- Emergent scar lines in chaotic advection of passive directors
Cited by in corpus (5)
- Navigation of micro-swimmers in steady flow: the importance of symmetries
- Alignment statistics of rods with the Lagrangian stretching direction in a channel flow
- Anisotropic particles in two-dimensional convective turbulence
- Prolate spheroids settling in a quiescent fluid: clustering, microstructures and collisions
- Folding dynamics and its intermittency in turbulence