Analysis of the interfacial mixing in the gravity-driven counterflow through a large vertical opening using Large Eddy Simulation

Abstract

The study of natural convection flows in multizone enclosures is a topic of great importance due to its direct influence on room air circulation patterns, distribution of indoor air contaminants, and thermal comfort inside buildings. In this research, ANSYS Fluent is used to investigate the density-driven bidirectional flow through a large vertical opening connecting two isothermal reservoirs, the so-called bulk flow regime. Many research works on the natural convection flow through a large vertical opening between two enclosures have been done. However, they paid less attention to the unsteady flow structures generated by the sophisticated bidirectional flow, especially in the middle of the doorway. Large Eddy Simulation (LES) results show the development of unsteady flow structures in the middle of the doorway, a phenomenon called “interfacial mixing”. This phenomenon has been hardly documented in the literature, only using experiments. Even though unsteady flow structures develop, they do not significantly affect bulk quantities such as the discharge coefficient (Cd).