Modelling of Tide and Tidally Induced Hydro-Sedimentary Processes in the Eastern Part of the English Channel
Abdellatif Ouasine, Hassan Smaoui, and Alexei Senchev
This study used a two-dimensional numerical model to study the hydrodynamical regime (tidal and residual currents) in the eastern English Channel and a one-dimensional vertical model to study the processes of suspended sediment transport in this area. The two-dimensional numerical model used nonuniform grid sizing with local refinement in regions with complex seabed morphology. The model was also applied in conjunction with a Total Variation Diminishing (TVD) numerical scheme to estimate the freshwater width band that characterised a front along the French coast. Results were compared with High Frequency radar velocity measurements of some major tidal constituents: M2, S2, N2, and M4. Differences observed in the amplitudes (semimajor axis), phases, and orientations of synthesised current ellipses were analysed in detail. Eulerian residual circulation appeared to be sensitive to seabed morphology and revealed a central gyre that was not revealed by previous models. This new feature was also observed using high-frequency measurements. In the one-dimensional vertical model, turbulence generated at the seabed was computed using a two-equation closure describing the time-space evolution of turbulent kinetic energy k and turbulent master length l (k–kl model). The total suspended sediment load predicted by this model was compared to measurement data collected from two levels of the water column.