Eulerian multiphase framework for the simulation of continuum fluid mechanics. Application to granular flows with free surface. Part 1: Numerical aspects, part 2: physical aspects


Granular column collapse under gravity is a benchmark problem for several applications from geophysics to industry. It has been shown experimentally, for 2D and 3D granular columns of initial aspect ratio a=hi/ri (initial height/initial width or radius), that for large enough values of a, the final width or radius r_infinite, reached after spreading, obeys the scaling law (r_infinite- ri) / di ≈ a^2/3 in 2D and a^1/2 in 3D flows. Moreover it was shown that the normalized distance-time data (t, x) plot exhibits a universal shape, independently of the grain type.

In this talk, we present an eulerian multiphase framework, based on parallel finite element techniques to study the pertinence and sensitivity of the mu(I) model to predict the case of 2D and 3D granular column collapse flows. A time-dependent regularized algorithm is proposed to solve this model, combined with anisotropic mesh adaptation to capture accurately the quasi-static vs. inertial flow zones, and using a variational multiscale method. A Level-Set method, based on self-reinitialization of the signed distance function, aims to capture and follow efficiently the interface between the fluid/air domain.


Rudy Valette
Elie Hachem
CEMEF Centre for Material Forming at the Ecole Nationale Supérieure des Mines de Paris