A comparative study of subgrid scale models in homogeneous isotropic turbulence

TLDR

Large‑eddy simulation models appear largely insensitive to the choice of subgrid‑scale model, according to recent studies. The study aims to investigate LES sensitivity to SGS models by simulating forced and decaying homogeneous isotropic turbulence across Taylor Reynolds numbers 35–248 with contemporary SGS models. The authors performed LES of forced and decaying homogeneous isotropic turbulence at Taylor Reynolds numbers 35–248 with various SGS models, compared the results to DNS and a theoretical energy‑spectrum model, and analyzed the resolved flow through morphology, enstrophy, strain, stretching, SGS kinetic energy, viscosity, and eigenvalue–vorticity correlations. While overall flow characteristics are largely SGS‑model independent, significant differences emerge in SGS kinetic energy and interscale energy transfer.

Abstract

Recently, a number of studies have indicated that Large Eddy Simulation (LES) models are fairly insensitive to the adopted Subgrid Scale (SGS) 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 various 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 the energy spectrum. The resolved flow is examined by visualizing the morphology and by analyzing the distribution of resolved enstrophy, rate of strain, stretching, SGS kinetic energy, and viscosity. Furthermore, 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 differences between the models become apparent when the SGS kinetic energy and the interscale energy transfer are investigated.