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  • Open Access

Convective heat transfer patterns in plane-layer Rayleigh-Bénard convection revealed by transient almost-invariant sets

Aleksandar Badza1, Gary Froyland1,*, Roshan J. Samuel2, and Jörg Schumacher2

  • 1School of Mathematics and Statistics, UNSW Sydney, Sydney, NSW 2052, Australia
  • 2Institute of Thermodynamics and Fluid Mechanics, Technische Universität Ilmenau, P.O. Box 100565, D-98684 Ilmenau, Germany

  • *Contact author: g.froyland@unsw.edu.au
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Phys. Rev. Research 8, 023040 – Published 13 April, 2026

DOI: https://doi.org/10.1103/f9kk-jkvz

Abstract

Horizontally extended plane-layer convection flows are characterized by characteristic patterns of turbulent heat transfer due to the convective fluid motion consisting of a nearly regular ridge network where hot fluid rises and cold fluid sinks. Here, we analyze this transport behavior by the so-called inflated generator framework, which identifies quasistationary families of almost-invariant sets, derived from leading inflated generator eigenvectors. We demonstrate the effectiveness of this data-driven analysis framework in three-dimensional turbulent flow, by extracting transient characteristic heat transfer patterns as families of almost-invariant sets subject to a gradual evolution, which contribute least to the convective heat transfer.

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Phys. Rev. Research 8, 023040– Published 13 April, 2026
  • Received 8 October 2025
  • Accepted 11 March 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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