Direct numerical simulation of turbulent rotating Rayleigh–Bénard convection

The influence of rotation on turbulent convection is investigated with direct numerical simulation. The classical Rayleigh-Bénard configuration is augmented with steady rotation about the vertical axis. Correspondingly, characterization of the dynamics requires both the dimensionless Rayleigh number Ra and the Taylor number Ta. With increasing Ta the root-mean-square (rms) velocityvariations are found to decrease, while the rms temperature variations increase. Due to rotation a mean vertical temperature gradient develops, to partially compensate for the reduced convective heat transfer. Compared to the non-rotating case, at constant Ra = 2.5 10 the Nusselt number increases up to ≈ 5% at relatively low rotation rates, Ta < Tam ≈ 10 , and decreases strongly when Ta is further increased. A striking change in the boundary layer structure arises when Ta traverses an interval about Tam, as is expressed by the near-wall vertical-velocity skewness.