INVESTIGATION OF SUBGRID-SCALE TURBULENT KINETIC ENERGY IN CHANNEL FLOWS

We investigate the subgrid-scale (SGS) turbulent kinetic energy (hereafter referred to as SGS energy) and its transport equation by employing the stabilized mixed model (SMM) developed by Abe (2013). The prediction of the budget for the modeled transport equation is qualitatively well compared with the filtered DNS via the Gaussian filter. In addition, the production term balances with the dissipation rate in the outer region, which suggests that the transport equation can be reduced by assuming the equilibrium between them. We investigate five algebraic expressions for the SGS energy. Among them, the equilibrium form with a newly introduced damping function yields the best compared with the SMM. The zero-equation SMM (ZE-SMM) that employs the equilibrium form instead of the transport equation for the SGS energy provides quantitatively equivalent results as the original SMM. This study paves the way for constructing a convenient anisotropic SGS model that is robust even in coarse grid resolutions.