Richard J.A.M. Stevens

Physics of Fluids · University of Twente

Publication 11 · Thermal convection

Connecting flow structures and heat flux in turbulent Rayleigh-Bénard convection

E.P. van der Poel, R.J.A.M. Stevens, D. Lohse, Phys. Rev. E 84, 045303(R) (2011).

Main finding

Aspect-ratio changes can switch the number and stability of turbulent rolls, creating sharp jumps, coexistence, and initial-condition dependence in the heat transfer of two-dimensional convection.

Heat transport and roll-state occupancy against aspect ratio in two-dimensional convection
How to read the figure. (a, c) Heat transport against aspect ratio at two Prandtl numbers; (b, d) the fraction of time each roll state occupies, beneath. Sharp steps in transport coincide with changes in the dominant roll state - near an aspect ratio of 0.5 the triple-roll state gives way and the Nusselt number rises from about 16 to 24. Open the full-resolution figure. Figure 1. E.P. van der Poel et al. (2011). No separate licence is stated here; consult the original publication and credited source before reuse.

Why this matters

It provides a direct example of long-lived turbulent flow branches carrying measurably different heat fluxes at the same control parameters.

Research context

The roll-state transitions connect the earlier reversal mechanism to the later probe-classification warning. Wider-domain, free-slip, and superstructure studies test how these state-dependent heat-flux branches change when lateral confinement is relaxed.

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