Similarities between characteristics of convective turbulence in confined and extended domains

Ambrish Pandey, Dmitry Krasnov, Jörg Schumacher, Ravi Samtaney, Katepalli R. Sreenivasan

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


To understand turbulent convection at very high Rayleigh numbers typical of natural phenomena, computational studies in slender cells are an option if the needed resources have to be optimized within available limits. However, the accompanying horizontal confinement affects some properties of the flow. Here, we explore the characteristics of turbulent fluctuations in the velocity and temperature fields in a cylindrical convection cell of aspect ratio 0.1 by varying the Prandtl number Pr between 0.1 and 200 at a fixed Rayleigh number Ra=3×1010, and find that the fluctuations weaken with increasing Pr, quantitatively as in aspect ratio 25. The probability density function (PDF) of temperature fluctuations in the bulk region of the slender cell remains mostly Gaussian, but increasing departures occur as Pr increases beyond unity. We assess the intermittency of the velocity field by computing the PDFs of velocity derivatives and of the kinetic energy dissipation rate, and find increasing intermittency as Pr decreases. In the bulk region of convection, a common result applicable to the slender cell, large aspect ratio cells, as well as in 2D convection, is that the turbulent Prandtl number decreases as Pr−1/3.
Original languageEnglish (US)
Pages (from-to)133537
JournalPhysica D: Nonlinear Phenomena
StatePublished - Oct 20 2022

Bibliographical note

KAUST Repository Item: Exported on 2022-10-31
Acknowledged KAUST grant number(s): URF/1/4342-01
Acknowledgements: We are honored to contribute to this special issue for Charlie Doering, who inspired our research via fruitful discussions over several decades; he was a positive force and will be missed. KRS, JS and AP are dismayed to note the untimely demise on July 24 of their coauthor, Ravi Samtaney, during the revision of this manuscript. JS wishes to thank the Isaac Newton Institute for Mathematical Sciences, Cambridge, United Kingdom, for support and hospitality during the program Mathematical aspects of turbulence: where do we stand? where part of this work was undertaken. This research was supported by the KAUST, Saudi Arabia Office of Sponsored Research under Award URF/1/4342-01, and also by EPSRC, United Kingdom grant EP/R014604/1. The three-dimensional large-aspect-ratio data were obtained at the SuperMUC-NG compute cluster within the project pn68ni of the Leibniz Rechenzentrum Garching. The authors gratefully acknowledge SHAHEEN II of King Abdullah University of Science and Technology, Saudi Arabia (under Project No. k1491), as well as DALMA and JUBAIL clusters at NYU Abu Dhabi for providing computational resources via the Center for Space Science (grant G1502).

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Condensed Matter Physics


Dive into the research topics of 'Similarities between characteristics of convective turbulence in confined and extended domains'. Together they form a unique fingerprint.

Cite this