Direct Numerical Simulations of Non-Oberbeck-Boussinesq Effects in Turbulent Rayleigh-Bénard Convection of Water

Turbulent Rayleigh-Bénard convection of water is studied by means of three-dimensional Direct Numerical Simulations. The generated flow fields are analysed with respect to deviations from the Oberbeck-Boussinesq case. For this purpose simulations in a cylindrical domain with various temperature differences between the plates are performed. We obtain an asymmetry in the boundary layers and the plume dynamics, an enhancement of the bulk temperature and a decrease of the Nusselt number with increasing temperature difference