Numerical simulation of natural convection in vertical cylinders partially cooled from above

Steady natural convection in vertical cylinders heated from below and partially cooled from above is studied from a numerical point of view. The governing equations for natural convection are discretized employing a mixed Fourier - Finite volume method using the SIMPLEC algorithm as velocity decoupling strategy. Calculations are performed for constant Prandtl number, Pr=6.667, and Rayleigh number over a range of $10^3 \leq Ra \leq 10^5$ and cooler size $0.125\leq \gamma \leq 1$ and for an aspect ratio (height/diameter) $0.5\leq a \leq 1.25$. Convective complex three-dimensional flow structures are presented.