High reynolds-number assessment of a multifractal subgrid-scale model

We report further results from our a priori assessment of a multifractal subgrid-scale model for large-eddy simulation. In this paper, we compare the model's ability to recover components of the subgrid-stress tensor T*ij and the subgrid energy-production V* field in low and high Reynolds-number turbulence, (Reλ ~ 160 and Reλ ~ 2550). We find that in comparisons with DNS data, the model recovers T*ij with correlations of p ~ 0.855 and p ~ 0.635 in the lower and higher-Re cases, respectively. We also report correlations between DNS and model values for the SGS energy-production field V* of p ~ 0.860 in the lower Reynolds-number context and p ~ 0.804, in the more turbulent flow. We further examine the model's ability to recover components of the averaged subgrid-velocity field u^sgs, which shows correlations of p ~ 0.915. We also analyze the individual terms within the decomposition of T*ij itself. These tests in sum indicate that the present multifractal model recovers significant structural characteristics of the subgrid field. The comparisons also suggest possible higher-order refinements to the model. Finally, we set forth in some detail a multifractal model for the Reynolds stresses in the Reynolds-Averaged Navier-Stokes equations.