Descriptif

INSTABILITIES AND TURBULENCE

Résumé

Les écoulements turbulents sont au coeur de nombreux problèmes physiques, environnementaux et industriels. La turbulence est due généralement à la destabilisation d'un écoulement "laminaire", conduisant à un comportement "chaotique" de différentes quantités physiques. Dans ce cours, nous allons présenter comment prendre en compte la complexité de ces écoulements, partant de l'étude de l'instabilité des écoulements jusqu'à la description statistique de la turbulence et montrant à la fois les concepts fondamentaux de la turbulence et leurs applications pratiques.

Scope
Instability, unpredictability and disorder are very often encountered in natural, technological, ecological, economic and social systems with important consequences on forecasting, design and decision making. These concepts have been historically introduced in the study of the laminar-turbulent transition in fluid flows, where they still represent an active field of research. Some questions of interest in this context are: Why `laminar' solutions, having a maximum degree of symmetry, become unstable and are replaced by less symmetric solutions? What are the reasons of unpredictability in non-linear systems? Is there anything predictable in turbulent flows?  The scope of this course is to present our current understanding of these issues.

Instructor
Christophe Josserand, Ecole Polytechnique

Requirements : A basic knowledge of fluid mechanics (e.g. MEC432 or MEC433) is useful

Evaluation mechanism : Written exam  

ECTS Credits  : 4