Richard J.A.M. Stevens

Physics of Fluids · University of Twente

Publication 10 · Thermal convection

Effect of aspect ratio on vortex distribution and heat transfer in rotating Rayleigh-Bénard convection

R.J.A.M. Stevens, J. Overkamp, D. Lohse, H.J.H. Clercx, Phys. Rev. E 84, 056313 (2011).

Main finding

Rotation enhances heat transfer after a geometry-dependent onset. The onset moves to larger 1/Ro as Γ decreases. Above onset, the sampled absolute DNS Nu curves and vortex-covered fractions approximately collapse across aspect ratios even though their nonrotating values differ.

Heat transport ratio against inverse Rossby number for four cell aspect ratios
How to read the figure. Nusselt number under rotation, normalised by its non-rotating value, against the inverse Rossby number, in cells of aspect ratio 0.5, 1, 4/3 and 2, with both experiment and simulation at several Rayleigh numbers. The onset of enhancement moves to larger inverse Rossby number as the cell becomes more slender: where rotation begins to help depends on the geometry. Above onset the curves collapse across aspect ratios even though their non-rotating heat transport differs. Open the full-resolution figure. Figure 2. R.J.A.M. Stevens et al. (2011). No separate licence is stated here; consult the original publication and credited source before reuse.

Why this matters

Local vortices can erase the aspect-ratio dependence of global heat transfer above the rotation-dependent onset.

Research context

The onset moves to stronger rotation as the cylinder becomes more slender. Above onset, the simulated Nusselt-number curves and vortex-covered fractions approximately collapse across the four tested aspect ratios, linking the result to the related finite-size model.

Read the article View in the complete publication list Related thermal convection research