Richard J.A.M. Stevens

Physics of Fluids · University of Twente

Publication 8 · Thermal convection

Finite-size effects lead to supercritical bifurcations in turbulent rotating Rayleigh-Bénard convection

S. Weiss, R.J.A.M. Stevens, J.Q. Zhong, H.J.H. Clercx, D. Lohse, G. Ahlers, Phys. Rev. Lett. 105, 224501 (2010).

Main finding

Heat-transfer enhancement begins above a finite 1/Ro_c in the measured and simulated finite cylinders. At fixed post-onset rotation, the horizontal vortex-covered fraction grows approximately linearly and is depleted near the sidewall.

Critical inverse Rossby number against inverse aspect ratio
How to read the figure. The onset of rotational heat-transport enhancement, as the critical inverse Rossby number, against the inverse aspect ratio of the cell. The points fall on a straight line through the origin: the onset is set by the cell's finite width, near 0.4 at aspect ratio one and vanishing as the cell becomes infinitely wide. What looks like a transition of the flow is in part a property of the container. Figure 4 carries the vortex-covered fraction that grows after onset. Open the full-resolution figure. Figure 2. S. Weiss et al. (2010). No separate licence is stated here; consult the original publication and credited source before reuse.

Why this matters

Finite aspect ratio can shift an apparent transition and alter its observed bifurcation.

Research context

Rotation produces vertically aligned vortices and Ekman pumping, while sidewall exclusion suppresses their cross-sectional area in smaller cells. The related aspect-ratio study tests the post-onset collapse more fully.

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