Flood wave simulation with 1D-2D coupled models.

Urban flooding has become a very important and growing issue around the world. With the need to improve modelling accuracy and gaining computational time, this research is focused on new coupled modelling approaches where the 2D model of a flood plain is combined with the 1D open channel flow model. Both models are based on a conservative upwinding cell-centred finite volume scheme. The topography is represented with cross sections for the 1D model and with DEM (Digital Elevation Model) in a quadrilateral structured grid for the 2D model. Two strategies have been explored: frontal and lateral coupling and results of both are presented. The coupled model has been applied to dam break problems as first calibration test cases, giving satisfactory results. The numerical results have been compared with a fully 1D model and a fully 2D model as well as with experimental measurements. ing in large rivers wanted to be analyzed. 1D models do not give the necessary accuracy in the flood plains and 2D models are too much time consuming. That is the reason of searching for coupled 1D-2D models. 1D free surface flow is governed by the shallow water equations in conservative form representing mass and momentum conservation along the main direction of the flow given by