Title : Collapse of dense suspensions: a model to understand unsteady gravity driven flows
Contact : Marie Rastello
Abstract : The slumping of a complex material initially at rest is a useful laboratory configuration to model and mimic several mechanisms observed in geophysical applications (avalanches, debris flows, mud flows, generation of impulse wave…). A classical outcome of interest using such configuration is the prediction of the length on which the front of the current can spread depending on its initial state. Such prediction requires the knowledge of the whole spatio-temporal dynamics, inertial vs viscous or plastic, which can strongly depends on the contents of the considered complex material. For this purpose, we focus here on idealized materials containing solid grains and/or viscous fluids, using both resolved numerical simulations and experiments at the laboratory scale. Complex behaviours, as regime transition in time and/or in space, associated with the internal structure of the flowing material will be highlighted and discussed. Beyond such complexity, attention is paid on resulting to simple scaling laws relating the front spreading or the final state, when relevant, and the initial state.
