Large eddy simulation of thermal driven cavity: Evaluation of sub-grid scale models and flow physics

Three eddy-viscosity and one non-eddy-viscosity type sub-grid scale models have been evaluated in large eddy simulations of buoyant turbulent flows in the three-dimensional thermal driven cavity of aspect ratio 4. The eddy-viscosity models considered include the traditional dynamic Smagorinsky model, and the recently developed dynamic Vreman and constant coefficient Sigma models. The non-eddy-viscosity Stretched Vortex model has also been evaluated. A high-order numerical framework has been used for the present LES of buoyant turbulent flows. Excellent comparison to DNS data has been obtained using dynamic Smagorinsky, Sigma and Stretched Vortex models, while more tests are required to ascertain the applicability of the dynamic Vreman model for buoyant turbulent flows. The use of WENO advective scheme for scalars has been established by comparing to results using BQUICK scalar advective scheme. Finally, the flow structure in the thermal cavity has been examined in detail, and features such as inhomogeneity, wave-vortical interactions, the turbulent kinetic energy budget, and the boundary layer dynamics have been studied. In particular, the near wall behavior of the turbulent shear stress and the turbulent streamwise heat flux has been studied in conjunction with their respective production terms.