Stochastic modelling of turbulent flows for numerical simulations
Résumé
The stochastic model proposed by Mémin (2014) for turbulent flow simulations is analysed, both theoretically and numerically. It is shown to be a generalisation of the classical large-eddy simulation approach, and to describe a richer physics. The model does not lead to the eddy-viscosity assumption and can be reduced to Smagorisky model under restrictive hypotheses; hence, it can be considered as a generalisation of classical models. Simulations of a turbulent channel flow at Re τ = 590 shows the presence of physical phenomena usually not reproduced; namely a weak turbophoresis and of a turbulent compressibility linked to streaks structures. The turbulent kinetic energy budget suggests that the model is more effective in dissipating energy near the wall. For the sake of completeness, alternative and detailed derivation of the stochastic model is reported in detail in the appendix.
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