In:
Physics of Fluids, AIP Publishing, Vol. 21, No. 10 ( 2009-10-01)
Abstract:
Large eddy simulation (LES), in which the large scales of turbulence are simulated while the effects of the small scales are modeled, is an attractive approach for predicting the behavior of turbulent flows. However, there are a number of modeling and formulation challenges that need to be addressed for LES to become a robust and reliable engineering analysis tool. Optimal LES is a LES modeling approach developed to address these challenges. It requires multipoint correlation data as input to the modeling, and to date these data have been obtained from direct numerical simulations (DNSs). If optimal LES is to be generally useful, this need for DNS statistical data must be overcome. In this paper, it is shown that the Kolmogorov inertial range theory, along with an assumption of small-scale isotropy, the application of the quasinormal approximation and a mild modeling assumption regarding the three-point third-order correlation are sufficient to determine all the correlation data required for optimal LES modeling. The models resulting from these theoretically determined correlations are found to perform well in isotropic turbulence, with better high-wavenumber behavior than the dynamic Smagorinsky model. It is expected that these theory-based optimal models will be applicable to a wide range of turbulent flows, in which the small scales can be modeled as isotropic and inertial. The optimal models developed here are expressed as generalized quadratic and linear finite-volume operators. There are significant quantitative differences between these optimal LES operators and standard finite-volume operators, and these differences can be interpreted as the model of the subgrid effects. As with most other LES models, these theory-based optimal models are expected to break down near walls and other strong inhomogeneities.
Type of Medium:
Online Resource
ISSN:
1070-6631
,
1089-7666
Language:
English
Publisher:
AIP Publishing
Publication Date:
2009
detail.hit.zdb_id:
1472743-2
detail.hit.zdb_id:
241528-8
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