Large-eddy simulation of turbulent buoyancy-driven flow in a rectangular cavity

Turbulent buoyancy-driven flow in a rectangular cavity with two differentially heated opposite walls is investigated numerically by means of large-eddy simulation (LES). Different dynamic global-coefficient subgrid-scale models for weakly compressible flows are applied to simulate the natural convective flow. It is shown that transition of the boundary layer is delayed in cases where the model coefficients are fixed or changing dynamically according to the Germano identity. On the contrary, in the ‘global equilibrium’ approach, the result shows an earlier change in flow regime due to lower subgrid-scale viscosity. Further, it is also demonstrated that three-dimensional effects of the natural convective flow may be significant due to the presence of adiabatic side walls.

► Dynamic global-coefficient models are applied to turbulent natural convection.
► Reasonable agreement is found for the mean flow and thermal quantities.
► Turbulence quantities show larger discrepancies in capturing onset of transition.
► Presence of adiabatic side walls seems to induce disturbances in the cavity.