Large eddy simulations of an air-helium buoyant jet in a two vented enclosure: influence of the outlet boundary condition.
Résumé
We present numerical results from large eddy simulations (LES) of an air-helium buoyant jet in a two
vented enclosure. The geometrical configuration mimics the experimental setup studied at CEA Saclay.
The dimension of the enclosure was chosen to ensure a laminar/turbulent transition occurring at about the middle height of the cavity. This study focuses on the influence of the boundary conditions on the jet development and its entrainment behavior. We observe that applying constant pressure outlet boundary conditions directly at the vent surfaces underestimates the volumetric flow rate of air entering the enclosure. On the contrary, modeling an exterior region in the computational domain better predicts the air flow-rate entrance. Results are then in good agreement with the experimental PIV data.