COMPARATIVE-STUDY OF SUBGRID SCALE MODELS IN HOMOGENEOUS ISOTROPIC TURBULENCE

Recently, a number of studies have indicated that Large Eddy Simulatio n (LES) models are fairly insensitive to the adopted Subgrid Scale (SG S) models. In order to study this and to gain further insight into LES , simulations of forced and decaying homogeneous isotropic turbulence have been performed for Taylor Re numbers between 35 and 248 using var ious SGS models, representative of the contemporary state of the art. The predictive capability of the LES concept is analyzed by comparison with DNS data and with results obtained from a theoretical model of t he energy spectrum. The resolved flow is examined by visualizing the m orphology and by analyzing the distribution of resolved enstrophy, rat e of strain, stretching, SGS kinetic energy, and viscosity. Furthermor e, the correlation between eigenvalues of the resolved rate of strain tensor and the vorticity is investigated. Although the gross features of the flow appear independent of the SGS model, pronounced difference s between the models become apparent when the SGS kinetic energy and t he interscale energy transfer are investigated. (C) 1997 American Inst itute of Physics.