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Conf’luence Mickaël Bourgoin

13 février 2011

Turbulent Transport of material particles : finite size and density effects
24 février 2011 à 10h30
Amphithéâtre Nougaro
Mickaël Bourgoin, Chargé de Recherche au Laboratoire des Ecoulements Géophysiques et Industriels, Grenoble.

Résumé :
Predicting the dynamics of inertial particles dispersed and transported in a turbulent flow remains a challenge with important applications in industrial and natural systems : dust and pollutants dispersion, industrial mixers, sediments in rivers, dispersion of gametes of marine animals, water droplets in clouds, atmospheric balloons, etc. One of the main difficulties lies in the intrinsic multi-scale nature of turbulence : depending on their size and density, particles will interact with structures of the carrier flow at different time and spatial scales. How the coupling between particle dynamics and fluid dynamics is influenced by size and density effects remains an open question and a very active field of research.
The goal of the present work is to investigate inertial dynamics of material particles in a turbulent flow. To achieve this, we have performed a systematic experimental investigation of how size and density affect the turbulent dynamics of particles. In a first step we have considered isolated particles and the focus is put on the characterization of the turbulent forcing experienced by the particle. An important aspect of this work has therefore focused on characterizing particles velocity and acceleration as a function of size and density. We find that while some features do exhibit specific size and density effects, others preserve an extremely robust turbulent signature, regardless of particles size and density, in contrast with usual point particle models predictions.