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Nonlocality and intermittency in three-dimensional turbulence

type de publication      article dans une revue internationale avec comité de lecture
date de publication 2001
auteur(s) Laval Jean-Philippe; Dubrulle Bérengère; Nazarenko Sergey V.
journal (abréviation) Physics of Fluids (Phys. Fluids)
volume (numéro) 13
numéro de papier 7
pages 1995 – 2012
résumé Numerical simulations are used to determine the influence of the non-local and local interactions on the intermittency corrections in the scaling properties of 3D turbulence. We show that neglect of local interactions leads to an enhanced small-scale energy spectrum and to a significantly larger number of very intense vortices (tornadoes) and stronger intermittency. On the other hand, neglect of the non-local interactions results in even stronger small-scale spectrum but significantly weaker intermittency. Based on these observations, a new model of turbulence is proposed, in which non-local (RDT-like) interactions couple large and small scale via a multiplicative process with additive noise and the local interactions are modeled by a turbulent viscosity. This model is used to derive a simple toy version of the Langevin equations for small-scale velocity increments. A Gaussian approximation for the large scale fields yields the Fokker-Planck equation for the probability distribution function of the velocity increments. Steady state solutions of this equation allows to qualitatively explain the anomalous corrections and the skewness generation along scale.
mots clés turbulence, simulation, model
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