Direct numerical simulation of turbulent rotating Rayleigh-Benard convection

The influence of rotation on turbulent convection is investigated with direct numerical simulation. The classical Rayleigh-Benard configuration is augmented with steady rotation about the vertical axis. Correspondingly, characterisation of the dynamics requires both the dimensionless Rayleigh number Ra and the Taylor number Ta. With increasing Ta. the root-mean-square (rms) velocity-variations are found to decrease, while the rms temperature variations increase. Under rotation a mean vertical temperature gradient develops in the bulk. Compared to the non-rotating case, at constant Ra = 2.5 x 10(6) the Nusselt number increases up to approximately 5% at relatively low rotation rates, Ta less than or similar to Ta-m = 10(6), and decreases strongly when To. is further increased. A striking change in the boundary layer structure arises when Ta traverses an interval about Ta-m, as is expressed by the near-wall vertical-velocity skewness.