On sub-grid scale modeling in a differentially heated cavity using coarse large eddy simulation

Abstract: Two widely used sub-grid scale models, the standard and the dynamic Smagorinsky models were tested in a simulation of the flow in a thermally driven 3D cavity at Rayleigh number of Ra=1E9. The main focus of the research is the response of the subgrid scale models to the coarse mesh and their ability to predict the flow in a thermally driven 3D cavity with the mesh resolution below generally accepted LES standards. The research is motivated by investigating a feasible modeling strategy for the particulate flow in the wall-bounded side-wall heated cavity. As URANS and hybrid RANS-LES models fail to produce modeled energy due to laminarization, the alternative is LES applied on the coarse mesh. In a quantitative manner, first and second-moment statistics are com-pared against both reference LES and experimental databases from literature. For first moment statistics, both models globally predict the flow field well. However, for higher moments, the dynamic model outperforms the standard Smagorinsky model using the same mesh resolution. In a qualitative fashion, we report the contours of both temperature and velocity fields as well as the near-wall turbulent coherent structures. Results of flow quantities are globally in very good agreement with both reference LES and experimental measurements at a fraction of the CPU power needed for conventional LES.