### Abstract

Vortical columns are key features of rapidly rotating turbulent Rayleigh-Benard convection. In this work we probe the structure of the sidewall boundary layers experimentally and show how they affect the spatial vortex distribution in a cylindrical cell. The cell has a diameter-to-height aspect ratio 1/2 and is operated at Rayleigh number $5.9 \times 10^9$ and Prandtl number 6.4. The vortices are detected using particle image velocimetry. We find that for inverse Rossby numbers 1/Ro > 3 (expressing the rotation rate in a dimensionless form) the sidewall boundary layer exhibits a rotation-dependent thickness and a characteristic radial profile in the root-mean-square azimuthal velocity with two peaks rather than a single peak typical for the non-rotating case. These properties point to Stewartson-type boundary layers, which can actually cover most of the domain for rotation rates just above the transition point. A zonal ordering of vortices into two azimuthal bands at moderate rotation rates 3 < 1/Ro < 7 can be attributed to the sidewall boundary layer. Additionally, we present experimental confirmation of the tendency of like-signed vortices to cluster on opposite sides of the cylinder for 1 < 1/Ro < 5. At higher rotation rates and away from the sidewall the vortices are nearly uniformly distributed.

Original language | Undefined |
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Pages (from-to) | 54002 |

Number of pages | 7 |

Journal | Europhysics letters |

Volume | 104 |

Issue number | 5 |

DOIs | |

Publication status | Published - Dec 2013 |

### Keywords

- Thermal Convection
- EWI-24133
- Rotating and swirling flows
- IR-88723
- METIS-302577

## Cite this

Kunnen, R. P. J., Corre, Y., & Clercx, H. J. H. (2013). Vortex plume distribution in confined turbulent rotating convection.

*Europhysics letters*,*104*(5), 54002. https://doi.org/10.1209/0295-5075/104/54002