Dynamic structure subgrid‐scale models for large eddy simulation

Abstract

AbstractLarge eddy simulation (LES) is based on separation of variable of interest into two parts—resolved and subgrid. The resolved part is obtained numerically using modified transport equation while the effect of the subgrid part is modelled using subgrid‐scale (SGS) models. In this paper we present and discuss new one‐equation LES models for SGS scalar flux, SGS scalar dissipation and SGS energy dissipation. The proposed models belong to a new family of SGS models—dynamic structure (DS) models. The DS models borrow the structure of the modelled term from the corresponding Leonard term, and a special scaling factor is then used which does not contain user‐specified constants. The models are evaluated a priori using available DNS data for a non‐reacting mixing layer and decaying isotropic turbulence; the evaluation results compare well with viscosity and similarity models. During the a priori tests, the DS models were found to perform better than dynamic viscosity and similarity models for various test‐to‐base filter size ratios and non‐symmetric filters. For a posteriori evaluation, the models are implemented into a high‐order finite‐difference code and an LES of decaying isotropic turbulence is performed. The results match the data available from the literature and DNS simulations. Copyright © 2005 John Wiley & Sons, Ltd.