Preliminary Analysis of the Dynamics of Buoyancy-driven Flows from an Enclosed Cylindrical Heat Source

The study presents a numerical analysis of the dynamics of time-dependent natural convection flow regimes, generated by a con- fined thermal source. The physical system considered is a 2D cavity of square cross-section, containing a horizontal cylindrical source, placed in central position. The heat carrier fluid is air at Prandtl number Pr = .7. The resulting flow is investigated with respect to the variation of the Grashof number, based on the gap between the upper cavity wall and the cylinder top. The relative dimensions of both cavity and source are fixed. The numerical scheme is based on a second order finite-volume discretization of the Navier-Stokes equations, solved on orthogonal Cartesian grids. Internal boundaries non-aligned with the grid are subjected to special treatment. Computations are carried out for four supercritical values of the Grashof number. Some preliminary con- siderations are drawn on the dynamical behaviour of the system, while representing the attractors of the computed time series in phase space, and observing their morphological structure.