Dr. Y. Dubief moved to Vermont in 2005 from the Center for Turbulence Research (Stanford University) where he was a research associate working on drag reduction in turbulent flows by addition of polymers . At UVM, Dr. Dubief has been developing and collaborating research programs in turbulence control by complex fluids, flow-surface interactions with application to erosion and ablation by turbulent flows, biophysics of blood coagulation under flow and lubrication in articular joints. Dr. Dubief is a fellow of the Vermont Advanced Computing Center. He contributes to the teaching of fluid-related and computing-related undergraduate and graduate courses.

Elasto Inertial Turbulence: A Numerical Discovery

Abstract: Elasto inertial turbulence (EIT) is a chaotic state os polymer flows, first discovered in numerical simulations of channel flows. The process behind the discovery of EIT provides critical information about the physics at play. The polymer model most commonly used for simulation of drag reduction with polymer additives, the FENE-P model, is notoriously hyperbolic, or stiff. Using appropriate numerical methods and resolutions not only revealed the existence of the phenomenon, it led to the identification of the key scales involved in the self-sustaining cycle of EIT. This seminar will present the current state of knowledge of EIT, including the different regimes (see Figure), a first coherent structure, and its existence in natural convection flows. The mechanism of EIT will be discussed in the context of energy transfer between polymers and flow. The talk will end on a few remarks about the possible connection between EIT and elastic turbulence, a chaotic state observed in inertialess flows.

14 October 2021, 16h3017h30

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14 November 2024

Webinar Elizabeth GUAZELLI

Bodies of revolution in shear flows at low inertia

Elisabeth Guazzelli's research interests are in the field of particulate multiphase flows, such as fluidized beds, suspensions, sedimentation and sediment transport. She has spent her entire career as a CNRS researcher, leading an active and diversified research group at the IUSTI laboratory of the University of Aix-Marseille, and has now moved to the MSC (Matière et Systèmes Complexes) laboratory of the University Paris Cité. She is Rector of the International Center for Mechanical Sciences in Udine (Italy). She has been Associate Editor of the Journal of Fluid Mechanics since 2005 and is currently JFM Rapids Editor. Fellow of the American Physical Society and of the European Mechanics Society (EUROMECH), she is the recipient of the EUROMECH Fluid Mechanics Prize in 2016 and the APS Fluid Dynamics Prize in 2023. She was elected an international member of the Istituto Veneto di Scienze, Lettere ed Arti in 2020 and of the US National Academy of Engineering in 2021.