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Lecture

Flow Instabilities: Understanding Unstable Flows

In course

ME-466: Instability

This course focuses on the physical mechanisms at the origin of the transition of a flow from laminar to turbulent using the hydrodynamic instability theory. ...

Description

This lecture covers various flow instabilities, including Vortex shedding, Saffman-Taylor, Flow separation, Tollmien-Schlichting, Rayleigh-Taylor, Lift-up and Streaks, Traffic waves, Meandering instability, Gravito-capillary waves, Taylor-Couette, Rayleigh-Plateau, Tearing instability, Rayleigh-Benard, Coiling instability, and Benard-Marangoni Kelvin-Helmholtz. The instructor explains methods to solve the Rayleigh equation, concepts of parallel flow instabilities, and the influence of viscosity on Kelvin-Helmholtz instability. The lecture also discusses the stability of plane Poiseuille flow and the influence of confinement on instability. MATLAB simulations and boundary layer analysis at increasing Reynolds numbers are demonstrated.

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Instructor

François Gallaire

Né le 26 février 1975, François Gallaire obtient, en 1998, le diplôme dingénieur de lEcole Polytechnique à Paris et, en 1999, un master en « Physique des liquides » à lUniversité Pierre et Marie Curie, toujours à Paris. Il rejoint ensuite le Laboratoire dhydrodynamique (LadHyX) à lEcole polytechnique où il soutient, en 2003, une thèse sur le thème des instabilités des jets tournants et sur le contrôle de léclatement tourbillonnaire sous la direction de Jean-Marrc Chomaz. En 2003, il est nommé chargé de recherche au CNRS au Laboratoire J.A. Dieudonné de lUniversité de Nice Sophia-Antipolis.En 2009, il rejoint l'EPFL pour y fonder le laboratoire des mécanique des fluides et instabilités (LFMI). Ses recherches se concentrent sur létude des propriétés fondamentales de stabilité des écoulements de fluides et sont guidées par les applications réelles, en particulier le contrôle des écoulements. Récemment, il a réalisé dimportantes contributions dans les domaines de la micro-fluidique (lanalyse de la manipulation par laser dune goutte dans un micro-canal) et la dynamique des bio-fluides (le descriptif mécanique de lanévrisme de laorte abdominale).

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