01/06/2018 – P. Jop – Wet granular material : When the capillarity shapes the interfaces

Séminaire régulier IUSTI – 1 juin 2018 – 11h salle 250

Wet granular material : When the capillarity shapes the interfaces

Pierre Jop – SVI, Aubervilliers

Blending grains with a liquid is often the first step in an industrial process, but the triphasic nature of the medium makes it difficult to give a global description [1]: Cohesion induced by capillary bridges [2] and the progression of liquid in the system create boundaries between zones of different mechanical behavior. Such spatial heterogeneities need to be erase during mixing steps for example. While the static behavior of a homogeneous, partially saturated media is rather well understood, the time evolution of a heterogeneous system requires more work. One key ingredient during this seminar is the capillary forces that constrain the movement of the grains. In the presentation, I will illustrate different situations inspired by industrial applications where the behavior of a granular material evolved with the amount of liquid. From experiments at high level of saturation, I will focus on the role of the liquid interfaces to describe the propagation of the fluid, the morphology of the interfaces and the mechanic of the media.<\br>
[1] S. Herminghaus, Dynamics of wet granular matter, Adv. Phys. 54 221-244 (2005).<\br>
[2] M. Scheel, R. Seemann, M. Brinkmann, M. Di Michiel, A.Sheppard, B. Breidenbach & S. Herminghaus , Morphological clues to wet granular pile stability, Nat. Mater. 7, 189-193 (2008).<\br>
[3]. G. Saingier, A. Sauret & P. Jop, Accretion dynamics on wet granular materials, Phys. Rev. Lett. 118, 208001 (2017).