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Fast numerical simulations of 2D turbulence using a dynamic model for subfilter motions

type de publication      article dans une revue internationale avec comité de lecture
date de publication 01-05-2004
auteur(s) Laval Jean-Philippe; Dubrulle Bérengère; Nazarenko Sergey V.
journal (abréviation) Journal of Computational Physics (J. Comp. Phys.)
volume (numéro) 196 (1)
  
pages 184 – 207
résumé We present numerical simulations of 2D turbulent flow using a new model for the subfilter scales which are computed using a dynamic equation linking the subfilter scales with the resolved velocity. This equation is not postulated, but derived from the constitutive equations under the assumption that the non-linear interactions of subfilter scales between themselves are small compared to their distortions by the resolved scales. Such an assumption results in a linear stochastic equation for the subfilter scales, which can be numerically solved by a decomposition of the subfilter scales into localized wave packets. The wave packets are randomly produced by the smallest of the resolved scales. They are further transported by the resolved-scale velocity and they have wavenumbers and amplitudes which evolve according to the resolved strain. Performance of our model is compared with direct numerical simulations of decaying and forced turbulence. For the same resolution, numerical simulations using our model allow for a significant reduction of the computational time (of the order of 100 in the case we consider), and allow to achieve of significantly larger Reynolds number than the direct method.
mots clés turbulence, simulation, LES
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