Numerical Modeling of the Submarine Debris Flows Run-Out Using SPH

Abstract

Differing form subaerial debris flows, submarine debris flows transport sediment across the continental shelf into deep ocean overcoming the resistance of seawater. Recently, submarine debris flow has been concerned by increasing researchers, owing to the unique characteristics of large mass movement and long run-out even at gentle slopes. It is therefore a potential threat to the offshore and coastal facilities. To identify the dynamic behaviour and the areas potentially at risk of flows, an accurate numerical method is needed to simulate such submarine debris flows. In this paper, we proposed a mesh-free particle method called smoothed particle hydrodynamics (SPH) method to simulate the dynamic behaviour of submarine debris flows. The Navier-Stokes equations were adopted as the governing equations and a Bingham model was adopted to describe the rheology of the viscoplastic fluids. Besides, a viscosity coefficient was introduced to consider the resistance of sea water. In this paper, we applied the SPH method to a geometric model of submarine debris flow to verify the accuracy of the SPH method. Considering the validity of parameters, we have tested different set of parameters to calculate this submarine debris flow, and compared the simulation results with the existing data. The simulation results provide a better understanding of the flow mechanism involved in submarine debris flows.