Natural convection in eccentric spherical annuli

This article presents a numerical study of the natural convection of a fluid within an eccentric spherical annuli in the Boussinesq approximation. The inner spherical boundary is set at a higher temperature than that of the outer spherical boundary. The presence of a constant body force drives the convective flow. A two-component thermal lattice Boltzmann method was used to perform the numerical experiments. As temperature difference increases, results show a transition from a conductive energy transport regime to a steady convective one. The convective flow becomes unsteady at higher temperatures. Numerical results are used to characterize the convective instability, the evolution of the flow patterns and the dependence of the Nusselt number on the Rayleigh number through these transitions.