Mean flow structure in horizontal convection

Abstract

We analyse the global flow structures in horizontal convection systems, where the heat supply and removal takes place through separated parts of a lower horizontal surface of a fluid layer. The results are based on direct numerical simulations for the length-to-height aspect ratio of the convection cell $\unicode[STIX]{x1D6E4}=10$, Rayleigh number $\mathit{Ra}$ from $3\times 10^{8}$ to $3\times 10^{11}$ and Prandtl number $\mathit{Pr}$ from 0.05 to 50. The structure of the mean flows in horizontal convection is described in terms of time-averaged spatial distributions of the temperature, velocity, kinetic energy, thermal and kinetic dissipation rates. A possible scenario of transition to turbulent horizontal convection in the whole convection cell of a large aspect ratio is discussed.