Lattice boltzmann method simulation of flows in cylinder with internal slotted hollow

The lattice Boltzmann method is used to simulate the natural convection in a cylindrical enclosure with an internal concentric slotted hollow. The Rayleigh number varied from 10⁴ to 10⁶ and the slotted ratio ranged from 0.1 to 0.5. Isotherms are used to observe the flow and heat transfer characteristics. Time variation of dimensionless temperature at a certain point is inspected and the u-v phase diagrams are mapped showing different flow patterns that include steady flow, periodic oscillatory flow, and quasi-periodic oscillatory flow. By comparing with experimental and numerical results in the existing literature, it is concluded that the oscillation phenomenon in this model is mainly caused by its own intrinsic features.