Simulation of dredged sediment releases into homogeneous water using a two-phase model

Dredging operations of navigation channels and harbours are regularly planned in order to maintain the nautical depth and to ensure the navigation safety. Depending on the quality of the dredged material (fixed by the Oslo convention, 1972), dredged sediments can be released into the sea or stored at the Earth’s surface to be cleaned up. The present study deals with release operations. We simulate the complete process (generation and settling of a sediment plume, propagation of a density current on the bottom) using a two-phase flow model. We show that in this case, the sediment (or solid) phase strongly differs from the motion of the water (or fluid) phase. Comparisons between numerical results and experiments are carried out in order to illustrate the effects of sediment diameter, initial concentration, and ambient current on the plume dynamics and on the density current. We obtain a correct agreement with experiments for the specific release case.

► A numerical model to solve Navier–Stokes equations for both fluid and solid phases. ► Simulating sediment releases into water with and without ambient currents. ► Justification of the use of a two-phase model. ► Simulating three stages: convective descent, impact and propagation on the bottom.