A subgrid-scale mixing model for large-eddy simulations of turbulent reacting flows using the filtered density function

摘要

The filtered density function approach [ Colucci et al., Phys. Fluids 10, 499 ( 1999); Jaberi et al., J. Fluid Mech. 401, 85 ( 1999)] for large- eddy simulations of initially nonpremixed turbulent reacting flows is extended to encompass the flamelet regime. This is done by developing a model which describes the effect of realistic, Arrhenius chemical kinetics on the subgrid mixing time scale for reactive scalars. The model is based on mapping closure and flamelet modeling and can readily be applied to many existing micro- mixing models where the time scales of the reacting scalars appear explicitly in the formulation. Testing of the model using spatially filtered direct numerical simulation data of a turbulent reacting jet [ Boersma, Center for Turbulence Research Annual Research Briefs ( Stanford University/ NASA Ames, 1999), pp. 59 - 72] show a significant improvement over the generally used estimate of substituting the time scale of the reacting scalars by that of a conserved scalar. The impact of internal intermittency on the performance of the new model is discussed. (C) 2003 American Institute of Physics. [References: 34]