Conditional statistics of thermal dissipation rate in turbulent Rayleigh-Bénard convection.

The statistical properties of the thermal dissipation rate in turbulent Rayleigh-Bénard convection in a cylindrical cell are studied by means of three-dimensional direct numerical simulations for a fixed Prandtl number Pr = 0.7 and aspect ratio Γ = 1. The Rayleigh numbers Ra are between 10(7) and 3 × 10(10).

Lagrangian tracer dynamics in a closed cylindrical turbulent convection cell.

Turbulent Rayleigh-Bénard convection in a closed cylindrical cell is studied in the Lagrangian frame of reference with the help of three-dimensional direct numerical simulations. The aspect ratio of the cell Γ is varied between 1 and 12, and the Rayleigh number Ra between 10(7) and 10(9). The Prandtl number Pr is fixed at 0.