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 models of large eddy simulation. The results obtained using a linear combination model and dynamic eddy viscosity model were compared with the exact SGS stress evaluated from the DNS data. The following conclusions are obtained. (1) Correlation coefficients between the exact cross term and the one predicted using the linear combination model and the original scale similarity hypothesis show values as high as 90%. (2) The SGS Reynolds stress predicted using the assumption of scale similarity shows the highest correlation with the filtered DNS data, while the correlation between the exact value and the value predicted using the linear combination model is low. (3) The stress predicted using the dynamic SGS model and the exact stress show low correlation which depends on the filter selection and the averaging volume.