Richard J.A.M. Stevens

Physics of Fluids · University of Twente

Publication 14 · Thermal convection

The role of Stewartson and Ekman layers in turbulent rotating Rayleigh-Bénard convection

R.P.J. Kunnen, R.J.A.M. Stevens, J. Overkamp, C. Sun, G.J.F. van Heijst, H.J.H. Clercx, J. Fluid Mech. 688, 422-442 (2011).

Main finding

The mean vertical sidewall-temperature gradient persists in regimes II and III after the coherent first-mode LSC signal becomes weak. Full-field DNS shows radial Ekman transport near the plates, return flow through sidewall Stewartson layers, and localized vertical motion consistent with the measured wall gradient.

Fourier mode energies against inverse Rossby number with three rotation regimes marked
How to read the figure. Energy in the azimuthal Fourier modes of the sidewall temperature against the inverse Rossby number, with the three rotation regimes marked, and the large-scale circulation strength beneath. The first-mode signal that identifies a coherent large-scale roll collapses as rotation increases while the residual grows: the global roll is lost. The sidewall temperature gradient that persists after that, and the Ekman and Stewartson transport that explains it, are in Figures 9 and 12. Open the full-resolution figure. Figure 5. R.P.J. Kunnen et al. (2011). No separate licence is stated here; consult the original publication and credited source before reuse.

Why this matters

A local sidewall signal can persist after the global large-scale roll has broken down.

Research context

Ekman suction drives radial transport along the plates, which returns through nested Stewartson sidewall layers. This pathway explains why a vertical wall-temperature gradient persists after the coherent first-mode circulation becomes weak.

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