Thermal convection is one of the most important heat transport mechanism and as such plays a crucial
role in many geo- and astrophysical systems. We study experimentally different aspects of thermal convection
using the Rayleigh-Bénard (RB) setup, where a fluid layer of height L, is confined by a warm plate from
below and a cold one from above.

A schematic of a cylindrical RB cell is depicted in figure 1. When the temperature difference Δ
between the plates is large enough, the fluid enclosed by the cylinder will start to transport heat by
buoyancy induced convection in addition to conduction. The temperature difference can be expressed in non-dimensional
form by the Rayleigh number * Ra * and is a measure of the system's driving strength. Likewise, the resulting
heat flux that passes through the plates and the fluid can be expressed by the non-dimensional Nusselt number
* Nu *. One important question is the dependence of *Nu(Ra) *.

A schematic of a cylindrical Rayleigh-Bénard convection (RBC) cell with diameter |

· Two-phase convection

· Rotating RBC

· Turbulent RBC and the ultimate-state transition

· Non-Oberbeck Boussinesq convection

To experimentally investigate turbulent heat convection at high

*Ra*numbers our group features the Göttingen "U-Boot".

References

[1] G. Ahlers, S. Grossmann, and D. Lohse, Rev. Mod. Phys.

**81**, 503 (2009)