Numerical experiments of turbulent thermal convection at high Rayleigh numbers

Understanding turbulent thermal convection is crucial for industrial, geophysical, and astrophysical problems but experiments at high Rayleigh numbers (Ra) sometimes show contradictory results. This is due to unavoidable technical limitations of the experimental set-ups that produce flows slightly different from the ideal Rayleigh-Benard problem. Numerical simulations intended as ideal experiments can help understanding these issues since all the extraneous factors can be cleanly sorted out. In this paper Direct Numerical Simulations (DNS) of a turbulent Boussinesq convection in a cylindrical cell of aspect-ratio Gamma = 1/2 up to Ra = 2.10(14) are presented and discussed.