Kinetic energy transport in Rayleigh-B\'enard convection

Convective systems are often characterized by scaling laws for the heat transport. Several studies have indicated that these scaling laws are inextricably linked to the viscous dissipation rate and therefore to the kinetic energy balance. In the present study, direct numerical simulations of turbulent Rayleigh-B\'enard convection are analyzed with respect to the horizontally averaged kinetic energy balance. Based on this budget equation, distinct regions where energy is produced, dissipated and transported by several flux processes are identified. These regions depend strongly on the Prandtl number, which gives new insights into the flow dynamics in the different Prandtl number regimes.