2D and 3D Modelling of Wave-Driven Currents in Presence of a Groin System in a Tidal Sea

摘要

Groins are one of the most used engineering structures for coastal zone and beaches protection. Numerical morphodynamic modelling of the surf zone is one way to assess the efficiency of such structures in terms of shore stability control. We report here some results of 2D and 3D wave-driven currents simulations in presence of a system of two groins, perpendicular to a straight coastline. Wave and current (2D and 3D) models are coupled within the hydro-informatics TELEMAC system, developed at EDF-LNH with the finite element technique. 3D computations particularly enables to account for the roller effect in the upper layer of the water column. A sensitivity analysis is also performed to quantify the influence of the groins spacing, the turbulence model used in the current model, and the bottom friction. Effect of tidal currents, parallel to the coastline, is also investigated by superimposing a positive or negative longshore pressure gradient in the forcing term of the current model. The alternative pressure gradient due to tide generate a dissymetric behaviour of the current pattern between the groins which can be of importance for the sediment transport budget. Further work will mainly consists of integrating the sediment transport model in the numerical system, and looking after the effect of mean sea level variation due to the tide.