Post-doc at Politecnico di Milano

Numerical experiments will be conducted to study turbulent Rayleigh-Bernard convection. This kind of flow is generated when a layer of fluid at rest is sufficiently heated from below and cooled from above. Increasing the temperature difference, the flow from steady progressively becomes a periodic oscillation and then a turbulent motion. The main dimensionless parameter governing this phenomenon is the Rayleigh number, representing a non-dimensional measure of the temperature difference applied across the fluid layer. The other fundamental parameter is the Prandtl number, which measures the relative propensity of the fluid to diffuse momentum and heat. In the study of this complex system, the aim is to find an asymptotic regime at very high Rayleigh and/or Prandtl numbers in which any of the currently proposed theories would be exactly true. Unfortunately, to perform physical experiments and numerical simulations in the asymptotic regime is challenging due to the current technological limitations. An additional complication is the difficulty of exactly representing the ideal case in the experiments. For these reasons there are discrepancies between data obtained by the different research groups. Direct numerical simulations will be performed to produce a contribution to this controversy that is dividing the scientific community.