LIQSEDFLOW: ROLE OF TWO-PHASE PHYSICS IN SUBAQUEOUS SEDIMENT GRAVITY FLOWS

The paper describes an extension of the computational code LIQSEDFLOW proposed by the authors. The salient features of the code lie in its capability to describe the multi-phased physics of subaqueous sediment gravity flows. Specifically, it combines Navier-Stokes/continuity equations and equations for the advection and hindered settling of grains for a liquefied soil domain, with a consolidation equation for the underlying, progressively solidifying soil domain via a transition layer characterized by zero effective stress and a small yet discernible stiffness. Evolutions of the flow and solidification surfaces are traced as part of the solution using a volume-of-fluid (VOF) technique. The predicted features of the gravity flows of initially fluidized sediments with different concentrations conform to the observed performances in two-dimensional flume tests. The present results demonstrate the crucial role of two-phase physics, particularly solidification, in reproducing the concurrent processes of flow stratification, deceleration, and redeposition in subaqueous sediment gravity flows.