ASSESSMENT OF SUBGRID-SCALE MODELS BY DIRECT NUMERICAL-SIMULATION OF A TEMPORALLY DEVELOPING TURBULENT MIXING LAYER

Assessment of subgrid-scale (SGS) models in large eddy simulation was conducted using direct numerical simulation data base of a temporally developing turbulent mixing layer. The direct numerical simulation dat a base carefully calculated by means of a spectral method was used for comparison of SGS models. In this paper, various SGS models for incom pressible turbulence were tested to clarify the characteristics of the models. The Smagorinsky model, the Bardina model and the GNS model pr edict the mean value of Reynolds stress very well, whereas the local s tructure of the Reynolds stress cannot be well represented by these mo dels. Among the three models, the Bardina model predicts the local str ucture best. As for the Cross terms, the Bardina model shows high corr elation with DNS data. The dynamic eddy viscosity model for total SGS stress predicts very small stress which is close to the Reynolds stres s.