Highly turbulent solutions of the Lagrangian-averaged Navier-Stokes alpha model and their large-eddy-simulation potential.

摘要: We compute solutions of the Lagrangian-averaged Navier-Stokes alpha - (LANS ) model for significantly higher Reynolds numbers (up to Re approximately 8300 than have previously been accomplished. This allows sufficient separation scales observe a inertial range followed by second specific LANS model. Both fully helical and nonhelical flows are examined, up 1300. Analysis third-order structure function scaling supports predicted l3 scaling; it corresponds k-1 energy spectrum smaller alpha. The itself shows different scaling, which goes as k1. latter is consistent with absence stretching in subfilter due Taylor frozen-in hypothesis employed closure derivation These two scalings conjectured coexist spatial portions flow. [E(k) k-1] subdominant k1 spectrum, but responsible direct cascade, no cascade can result from motions internal degrees freedom. demonstrate verification prediction size attractor resulting this scaling. From this, we give methodology either arriving at grid-independent model, or obtaining formulation large eddy simulation optimal context models. converged may not be best approximation numerical equations, since minimum error balance between truncation errors using instead primitive equations. Furthermore, small-scale behavior contributes reduction flux constant energy, leading shallower features, however, do preclude reproducing correctly intermittency properties high-Reynolds-number