From dry to wet granular material
Alban SAURET - Surface du Verre et Interface, UMR 125 CNRS/Saint -Gobain
Jeudi 9 avril à 14 h00 Amphithéâtre Nougaro
The mechanical properties of granular matter are affected by the additionof liquid which tunes the cohesion of the system : from dry grains to grains connected by capillary bridges and finally continuous liquid phase between grains.
The first part of this seminar will focus on flowing dry granular media :
the bulldozing motion of a sandpile driven forward by a vertical plate. I will
show that current rheology allows to satisfactorily predict the dynamic of spreading and the topography of the dune.
We will then consider fibers that are an anisotropic granular media, in which the addition of a small amount of liquid leads to the formation of capillary bridges. Unlike the bridges that form between spherical beads, the morphology of the liquid on a pair of fiber s can be tuned by their orientation. In particular, the possibility to tune the morphology has important implications for drying processes in fibrous media.
Finally, in the last part of the talk we will discuss the generation of tsunamis arising from subaerial landslides. This situation is modeled by a granular collapse from air into water using a model experimental setup.
Our study shows the complexity of the interactions between the granular media, the
water and the air.