Close to the shoreline, 2D modeling has shown weaknesses for sediment transport studies. Flows around the breaking zone being strongly 3 dimensional, a point with a nul current in a 2D circulation model can result from the integration of a current heading to the coast at the surface and an undertow on the bottom.
2D modeling of circulation does not allow a correct representation of sediment transport.
As a quasi-3D model, SHORECIRC gives the analytical solutions to the vertical distribution of horizontal velocities and takes into account the dispersive mixing due to these current variations over depth. Couling of currents over the bottom with orbital velocities enables the study of sediment transport close to the shoreline.
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Orbital velocities are provided by RefDif. |
Quasi 3D circulation provided by SHORECIRC. |
Wind induced circulation, which is important in Languedoc-Roussillon, is included too.
Several improvements of the code have been implemented in order to allow the model to handle realistic simulations: beaches with complex shorelines and/or emerged structures (such as the numerous groins and breakwaters one can find in the region) can now be studied. Coriolis force and Neumann lateral open boudary conditions have also been added.
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Depth integrated speed intensity over a sandbar (SHORECIRC). |
Vertical section of the quasi-3D velocity over a sandbar (SHORECIRC). |
Quasi 3D circulation, along with relevant forcings, evaluates the circulation and induced sediment transport inside the littoral cell (0 to 10m depth). Hence one can quantify the dominant transport mode (crosshore or alongshore) corresponding to typical wind and wave forcings for a given beach.
(credit: périscope.gr.free.fr)
