Seminar - Pierre Rognon - Flow of granular materials
Wednesday 13 May 2009, 1.10 pm - 1.55 pm
Civil Engineering Lecture Theatre 3
The understanding of granular materials is critical to many practical problems in geophysics, soil mechanics and industrial processes. As with other materials, it is important to predict the constitutive response as it is subjected to specific loading conditions. In this talk I will focus on the flowing properties of the granular matter. While their full comprehensive description is complex, or even impossible, I will show that the main characteristics of the granular rheology can be captured and understood from the analysis of a simpler model material.
I first present experiments on natural snow flows, and interpret the corresponding observations using discrete numerical simulations that model cohesive or polydispersed granular material. Then, I consider a model material made of fluid-immersed grains. I will highlight how the squeeze of the fluid between the grains can give rise to a long relaxation time and to an unexpected but often predictive mechanical behavior.