2011/09/28 by Victor Yakhot, Yakhot, Victor, John Wanderer +1
Earth and Planetary Sciences · Engineering · Physics and Astronomy · #Computational Fluid Dynamics and Aerodynamics #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #Fluid Dynamics and Turbulent Flows #Meteorological Phenomena and Simulations #physics.flu-dyn
paper · pdf · doi:10.48550/arxiv.1109.6188
arxiv created 2011/09/28 · openalex publication_date 2011/09/28 · arxiv updated 2011/09/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The original goal of Large Eddy Simulations of fully developed turbulent flows was to accurately describe large-scale flow features \bf u(Δ) at the scales r≥ Δ where Δ is a size of computational mesh. The effect of small-scale velocity fluctuations (r<Δ) was to be accounted for by effective transport coefficients (subgrid models) in the coarse-grained Navier-Stokes equations. It is shown in this paper that, due to anomalous inertial range scaling (intermittency) of the moments of velocity difference, the existing subgrid models are intrinsically incapable of quantitatively describing flow features at the scales r<NΔ with N≈ 10. This increases computational work approximately by a factor 103-104. The breakdown of the widely used Smagorinsky relation for the subgrid viscosity on the scales Δ/L<1 is demonstrated and a modification accounting for intermittency of the filtered out small-scale fluctuations is proposed.