Christian Geindreau, Univ. Grenoble Alpes, 3SR, Director of the Fed3G, Deputy Director of Tec21
CNRS, Laboratoire de physique, ENS (Lyon)
In spite of centuries of active research Turbulence remains one of the deepest mysteries of fluid mechanics. The complexity relies on the random and multi-scale nature of the phenomenon. This lecture will review the origin and the characteristics of fluid Turbulence, as well as the phenomenological framework and statistical tools commonly used to describe the phenomenon. These rely on the concept of energy cascade, introduced by L. Richardson in the 1920’s, later refined by A. Kolmogorov, who’s ideas still dominate the Turbulence research community.
INPT, Institut de Mécanique des Fluides de Toulouse
CNRS, LRP (Grenoble)
Courses objectives are the characterization of the link between the flow mechanical properties (flow field, shear or extensional stresses, viscoelasticity moduli) and the structural organizations (aggregation, orientation, phase changes). The goal is to bring an understanding of the mechanisms controlling the flows properties of colloidal dispersions used in several processes (membrane separation, extrusion, film casting) involved in several industrial applications (chemical, bio- and agro-industries, pharmaceutical, water treatment...)
Univ. Grenoble Alpes, LIPhy
Suspensions are encountered in nature as well as in various industrial processes. Suspensions refer to particles immersed in a liquid like mud, fresh concrete, blood, paints or ink to site but a few examples. A very recent interest with an exponential growing number of publications concerns active suspensions where particles can actively swim in the liquid phase like planktonic suspensions. Usually, the small size of the particles often means that the surrounding flow is dominated by viscous effects, and therefore that inertial forces can be neglected relative to viscous forces. This means that the Reynolds number associated with the particles is small and the flow can be considered as a Stokes flow. The present course aims at providing a physically based introduction to the dynamics of particulate suspensions and focuses on hydrodynamical aspects. We will also briefly summarize recent researches concerning active suspensions.
Univ. Grenoble Alpes, 3SR
The macroscopic mechanical behaviour of heterogeneous material strongly depends on the arrangement of the constituents according to various microstructures (granular or porous media, fibrous network) and the physical phenomena involved at the microscale (heterogeneity scale). A fine scale description of such material is often impossible due to the large number of heterogeneities.
In practice, a macroscopic equivalent modelling is more efficient. An overview of the different methods that can be used to derived such equivalent macroscopic behaviour will be given.
All participants are kindly asked to prepare a poster about their work that will be exposed over the whole school.
Please don't forget to bring your poster with you on Monday morning.
CNRS, Laboratoire de Physique, ENS (Lyon)
Because of its intrinsic multi-scale nature, the experimental characterization of turbulence requires dedicated metrological tools, capable to resolve (simultaneously if possible) the whole range of relevant involved scales (both in time and space). The present lecture will review the main contemporary instruments used by the scientific community for such high resolution and multi-scale disgnosis. These include Eulerian methods (such as hot-wire anemometry, laser-Doppler velocimetry and Particle Image Velocimetry) as well as new Lagrangian methods, based on acoustical and optical 3D particle tracking.
Turbulent flows are characterized by a large range of motion scales. When turbulent flows are studied by numerical simulations, the explicit discretization of the overall range of scales is still an issue, even with the exponential rise in computational capability over the last few decades. In this presentation, some methods to overcome this limitation will be presented. The methods can consist to model a part of the turbulent fields (RANS and LES approaches), but the methods can also consist to develop numerical algorithm to allow direct numerical simulation with a lower computational cost (hybrid method for turbulent mixing).
Univ. Grenoble Alpes, 3SR
Various advanced modeling approaches have been proposed to describe intriguing phenomena in solid mechanics. However, such models require experimental results, at the appropriate scales, with the appropriate sensitivities and under the appropriate loading conditions, to identify and characterize the important mechanisms controlling the material responses, to provide ground truth and to identify model input parameters. Unfortunately, traditional experimental methods often fall short of providing the necessary data for the increasingly ambitious modeling approaches. To address such shortcomings, new (advanced) experimental methods have been under development in recent years. This lecture summarizes some of the key developments in this area, with specific examples mostly (but not only) from geomechanics.
The macroscopic effective properties or behaviour of heterogeneous materials are commonly invstigated by solving specific boundary value problem on Representative Elementary Volume (i.e. at the microscale) arising from the homogenization process. Nowadays, these boundary value problems (BVP) are commonly solved on 3D images of the material obtained by microtomography or idealized microstructure. Different numerical methods (Finite volume differences, Finite Element method, Discret Element method…) can used to solved the BVP. An overview of these methods is presented and illustrated.
The participants will attend 2 out of the 10 proposed lab-courses (1 on Wednesday, the other one on Thursday). Groups of 4-5 participants will be made and each group will be given its planning and location depending on the chosen topic. The lab-courses will be held in parallel sessions at different places on the campus. The detailed description of the lab-courses can be seen here.
The Gala dinner will take place at the Restaurant "le 5" near the art museum of Grenoble.
The Restaurant is easily accessible by tram, line B, "Notre Dame Musée" stop (about 15 minutes from the university campus). View the map
The indicated schedule may change slightly.
University of Torino, Italy
Univ. Grenoble Alpes, LEGI
CNRS, LAUM, Le Mans, France
CNRS, ISTERRE, Grenoble
CNRS, EPOC, Univ. Bordeaux, France