Inverse centrifugal effect induced by collective motion of vortices in rotating turbulent convection
arXiv:2010.15384 · doi:10.1038/s41467-021-25838-3
Abstract
When a fluid system is subject to strong rotation, centrifugal fluid motion is expected, i.e., denser (lighter) fluid moves outward (inward) from (toward) the axis of rotation. Here we demonstrate, both experimentally and numerically, the existence of an unexpected outward motion of warm and lighter vortices in rotating turbulent convection. This anomalous vortex motion occurs under rapid rotations when the centrifugal buoyancy is sufficiently strong to induce a symmetry-breaking in the vorticity field, i.e., the vorticity of the cold anticyclones overrides that of the warm cyclones. We show that through hydrodynamic interactions the densely populated vortices can self-aggregate into coherent clusters and exhibit collective motion in this flow regime. Interestingly, the correlation of the vortex velocity fluctuations within a cluster is scale-free, with the correlation length being about 30% of the cluster length. Such long-range correlation leads to the collective outward motion of cyclones. Our study provides new understanding of vortex dynamics that are widely present in nature.
References in corpus (7)
- Large scale dynamics in turbulent Rayleigh-Benard convection
- Scale-free correlations in bird flocks
- Prandtl-, Rayleigh-, and Rossby-number dependence of heat transport in turbulent rotating Rayleigh-Benard convection
- Power-law versus exponential distributions of animal group sizes
- Deep rotating convection generates the polar hexagon on Saturn
- Multiple-resolution scheme in finite-volume code for active or passive scalar turbulence
- Fine vortex structure and flow transition to the geostrophic regime in rotating Rayleigh-Bénard convection