Comment on “A dynamic nonlinear subgrid-scale stress model” [Phys. Fluids 17, 035109 (2005)]

In these expressions, S̄ij = ūi,j + ūj,i /2 is the filtered rate-ofstrain tensor, and S̄ = 2S̄ikS̄ki 1/2 is a characteristic strain rate. The SGS viscosity SGS=CS̄ 2 S̄ , where ̄ refers to the length scale associated with the filter size. To simplify the comparisons presented below the last two terms of 1 are written here in terms of CS and S̄ , but the use of SGS =CS̄ 2 S̄ in 1 and 2a – 2c reveals that these two terms are actually independent of CS and S̄ . By adopting a methodology suggested by Wong, the model parameters CS, CW, and CN are calculated such that the local error function is minimized. The latter constraint implies the following linear equation system for CS, CW, and CN see the corresponding definitions of Wang and Bergstrom :