Physics of Fluids - Publications

Effect of aspect-ratio on vortex distribution and heat transfer in rotating Rayleigh-Bénard convection

arΧiv
Journal of Physics: Conference Series 318, 082009 (2011)

Authors

	Jim Overkamp
	Richard Stevens
	Detlef Lohse
	Herman J. H. Clercx

BibTeΧ

@article{1742-6596-318-8-082009,
  author={J Overkamp and R J A M Stevens and Detlef Lohse and Herman J H Clercx},
  title={Effect of aspect-ratio on vortex distribution and heat transfer in rotating Rayleigh-Bénard convection},
  journal={Journal of Physics: Conference Series},
  volume={318},
  number={8},
  pages={082009},
  url={http://stacks.iop.org/1742-6596/318/i=8/a=082009},
  year={2011},
  abstract={Numerical and experimental data for the heat transfer as function of the Rossby number Ro in rotating Rayleigh-Benard are presented for Pr = 4.38 and up to Ra = 4.52 × 10 9 . The aspect ratio is varied between Γ = 0.5 and Γ = 2.0. Without rotation, where the aspect ratio influences the global flow structure, we see a small aspect-ratio dependence in the Nusselt number. For stronger rotation, i.e. 1/ Ro ##IMG## [http://ej.iop.org/icons/Entities/gg.gif] {gg} 1/ Ro c , the heat transport becomes independent of the aspect-ratio. We interpret this finding as follows: In the rotating regime the heat is mainly transported by vertically-aligned vortices. Since these vortices are local, the aspect ratio has a negligible effect on the heat transport in the rotating regime. Indeed, an analysis of the vortex statistics shows that the fraction of the horizontal area that is covered by vortices is aspect-ratio independent when 1/ Ro ##IMG## [http://ej.iop.org/icons/Entities/gg.gif] {gg} 1/ Ro c . In agreement with the results of Weiss & Ahlers (2011) we find a vortex-depleted area close to the sidewall. Here, we show that there is also an area with enhanced vortex concentration next to the vortex-depleted edge region and that the absolute widths of both regions are independent of the aspect ratio. This proceeding is a summary of Stevens et al. (2011).}
}