Modeling the test SGS tensor T-ij: An issue in the dynamic approach

摘要

Based on Taylor series expansions for the filtered velocity field, we present an analytical study of the "Germano identity" used in the dynamic sub-grid scale (SGS) model for large eddy simulation (LES). We consider the case of explicit filtering defined in physical space and show that the choice of the length scale which characterizes the test SGS tensor T-ij is a main issue in modeling the "Germano identity." In the field of eddy-viscosity models, we demonstrate the accuracy of a Gaussian formulation l(fg)(2)=l(f)(2)+l(g)(2), based on a priori tests of fully developed pipe flow. More than a generalization of formal results [B. Vreman, B. Geurts, and H. Kuerten, J. Fluid Mech. 339, 357 (1997)], our study reveals constraints and limitations of the dynamic approach. (C) 2001 American Institute of Physics. [References: 35]