Dynamic testing of subgrid models in LES based on the Germano identity

Charles Meneveau and Joseph Katz
Department of Mechanical Engineering, The Johns Hopkins University
Baltimore MD 21218

ABSTRACT: Normally the Germano identity is used in LES of turbulent flows to evaluate model coefficients so as to minimize the square error associated with replacing a particular model in the identity. However, one can also explicitly evaluate this error and thus establish the accuracy with which a particular model is capable of reproducing the flow features at scales between the grid and test filters. This idea is tested a-priori based on top-hat filtered experimental data in the far field of a round jet [Liu et al., J. Fluid Mech. 275, p. 83 (1994)]. Of the models considered, the mixed nonlinear model yields the smallest error. This approach offers the capability to dynamically choose among available parameterizations, based only on the resolved fields during LES.

Phys. Fluids 11, p. 245 (1999)

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Reused with permission from Charles Meneveau, Physics of Fluids, 11, 245 (1999). Copyright 1999, American Institute of Physics.