FLUIDISATION BY PORE PRESSURE OF DENSE GRANULAR FLOWS: NUMERICAL SIMULATIONS VERSUS EXPERIMENTS

Alvaro Aravena (1, 2) , Laurent Chupin (3) , Thierry Dubois (3) , Olivier Roche (2)

1 Facultad de Ciencias Básicas
2 LMV - Laboratoire Magmas et Volcans
3 LMBP - Laboratoire de Mathématiques Blaise Pascal

A model accounting for fluidisation by pore gas pressure in dense granular flows is presented. A viscoplastic rheology, based on the Drucker-Prager criterium, is used to describe the granular medium which is a mixture of air and glass beads. The pore gas pressure, which satisfies an advection-diffusion equation, reduces the friction between the particles and thus the value of the apparent viscosity. As a consequence, dense fluidised granular flows can travel longer distances. In laboratory experiments, the run-out distance reached by dense granular columns when collapsing is almost doubled when fluidisation is applied. This fundamental result, in the context of pyroclastic density currents, is reproduced by numerical simulations performed with the fluidised model.

Mots clés: Dense granular flow; Viscoplastic rheology; Multiphase flow; Level Set Method

Domaines: Equations aux dérivées partielles [math.AP]; Analyse numérique [math.NA]

Alvaro Aravena, Laurent Chupin, Thierry Dubois, Olivier Roche. FLUIDISATION BY PORE PRESSURE OF DENSE GRANULAR FLOWS: NUMERICAL SIMULATIONS VERSUS EXPERIMENTS. 8th European Congress on Computational Methods in Applied Sciences and Engineering ( ECCOMAS 2022), Jun 2022, Oslo, Norway. ⟨hal-03726486v2⟩