Numerical modelling of heterogeneous sediment transport: new insights for particulate radionuclide transport and deposition
|Author(s)||Rivier Aurélie1, 2, Le Hir Pierre2, Bailly Du Bois Pascal1, Laguionie Philippe1, Morillon Mehdi1|
|Affiliation(s)||1 : Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PRP - ENV/SERIS/LRC, 50130 Cherbourg - Octeville, France
2 : Ifremer, Centre de Bretagne, DYNECO/DHYSED, CS 10070, 29280 Plouzané, France
|Meeting||Coastal Dynamics 2017. 12-16 June 2017, Helsingør, Denmark|
|Source||Proceedings of Coastal Dynamics 2017. Troels Aagaard, Rolf Deigaard, David Fuhrman. Part 26 Modelling of coastal sediment transport. Paper n°161. pp.1767-1778|
|Keyword(s)||sediment transport, numerical modelling, hiding, exposure, bedload, suspension|
A sediment transport module which solves simultaneously bedload and suspended load is developed, in a context of multiclass sediment transport. Different approaches are used to simulate each transport mode: (i) bedload transport results from divergence of transport capacity and (ii) suspension transport is solved using erosion and settling fluxes associated with advection/diffusion equation. A focus is made on the significance of hiding and exposure processes in case of heterogeneous sediment bed. Their influence is strong on bedload sediment transport, and induces specific trends of sediment sorting in sand dunes. The application to heterogeneous sediment dynamics in the macrotidal area of the Normand Breton Gulf (English Channel), show that hiding and exposure processes enhance the trapping of fine sediments (p articles <64 μm, on which radionuclides are likely to adsorb) in locations where coarsest sediments are dominant.