Séminaire de Mécanique d'Orsay

Le Jeudi 18 novembre 2021 à 14h00 - Salle des séminaires FAST-LPTMS (Bât. 530, salle C.120, 1er)

The effect of cohesion on the stability and collapse of a cohesive granular column

Adrien GANS
IPR - Rennes

Cohesive granular materials are encountered in many geophysical and industrial applications, examples being fine sand, cement, pharmaceutical powders and flours. Whereas many advances have been made in the description of cohesionless granular flows in various configurations, the behavior of cohesive powders remains elusive. In particular, one difficulty lies in the understanding of the cohesion force between the particles. For very small particles (typically below 10 µm in diameter), attractive forces like Van der Walls or electrostatic forces are dominant whereas for larger particles, humidity brings the necessary amount of water to build strong liquid bridges between particles and therefore creates a bulk cohesion. Since the concept of cohesion overlaps a great complexity, there is a need of a simple definition and a good control of the cohesion to perform quantitative experiments. Several experimental studies have been conducted using wet granular materials where the cohesion arises from capillary bonds. However, the main difficulty lies in the ability to control and reproduce the cohesion force between particles. Recently, a new cohesion controlled granular material (CCGM) has been developed where the cohesion originates from a polyborosiloxane coating of the glass particles. This approach has proven to be very useful to develop experimental studies where a bulk cohesion needs to be implemented. In this talk, I will present the results of our investigation about the effect of cohesion on the stability and the dynamics of the collapse of a cohesive granular column performed with the CCGM. The experiments will be compared to continuum numerical simulations based on a cohesive µ(I) rheology performed with the Basilisk Software (www.basilisk.fr).

Accès Salle des séminaires FAST-LPTMS (Bât. 530, salle C.120, 1er)