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Accueil > Actualités > Séminaires > Séminaires 2017

Mardi 7 novembre 2017 à 11h00 en salle K118

Simon Thalabard, Laboratoire Lagrange, Observatoire de la Cote d’Azur

Titre/Title : Turbulent dispersion from a point-source : insights from Markovian models.

Contact : Achim Wirth (direction LEGI)

Résumé/Abstract : Modeling how particles separate in a turbulent environment is a long-standing problem, that can be traced back to Richardson’s seminal description of the dispersion of particles clusters in terms of a scale-dependent diffusivity.
A practical outcome is to determine the concentration field induced by localized sources of particles, whose spatial correlation stem from an intricate interplay between the source statistics and the Lagrangian statistics of the turbulent field.
In this talk, I will highlight this interplay in the idealized ``point-source’’ setting, using simple Markovian models for the turbulent velocity field, such as the Kraichnan model and variations thereof. While unrealistic, those models provide an insightful framework to analyze genuine turbulent datasets, as obtained from direct numerical simulations. If time permits, I will then discuss various modeling strategies that can be used to incorporate Non-Markovian effects, in order to better capture the statistics of extreme Lagrangian events.