Verification of SGS-Stress Models by Direct Numerical Simulation of Compressible Homogeneous Isotropic Turbulence.

Abstract

Direct numerical simulation of three-dimensional compressible homogeneous isotropic turbulence was conducted by a spectral method to verify SGS stress models of large eddy simulation. A linear combination model and dynamic SGS model were compared with the exact SGS stress evaluated from the DNS data. From this study, the following conclusions are obtained. (1)Correlation coefficients between the exact cross-term and the modeled ones predicted by the linear combination model and the model following the original scale-similarity hypothesis show values as high as 90%. (2) The SGS-Reynolds stress predicted by the assumption of scale similarity shows the highest correlation, whereas the correlation between the exact one and the linear combination model is low. (3) The dynamic SGS model and the exact stress show low correlation which depends on the kind of filter and the averaging volume.