Biomedical subjects

A Paquier

Publications and source records attributed to A Paquier.

2 recordsLinked to original sources

PubMed2006

One-dimensional GIS-based model compared with a two-dimensional model in urban floods simulation.

A GIS-based one-dimensional flood simulation model is presented and applied to the centre of the city of Nîmes (Gard, France), for mapping flow depths or velocities in the streets network. The geometry of the one-dimensional elements is derived from the Digital Elevation Model (DEM). The flow is routed from one element to the next using the kinematic wave approximation. At the crossroads, the flows in the downstream branches are computed using a conceptual scheme. This scheme was previously designed to fit Y-shaped pipes junctions, and has been modified here to fit X-shaped crossroads. The results were compared with the results of a two-dimensional hydrodynamic model based on the full shallow water equations. The comparison shows that good agreements can be found in the steepest streets of the study zone, but differences may be important in the other streets. Some reasons that can explain the differences between the two models are given and some research possibilities are proposed.

Cities↗

PubMed2006

Comparison of numerical and experimental simulations of a flood in a dense urban area.

Although various numerical methods were used to simulate real floods occurring in cities, the validation of the models was never accurate because of the lack of data about location and event description and about observation for validation. In order to check the capacities of our 2-dimensional shallow water equations model to simulate an urban flood, we then decided to simulate numerically an experimental event with well known characteristics and accurate flow measurements. The physical model presented in (Ishigaki et al, 2003) represents the flooding of the city center of Kyoto in Japan due to an overflow from the Kamo river. The 2-dimensional numerical simulation of this event was then set up and the experimental and computed data were compared. It appears that the event was calculated quite fairly in terms of flow depth and flow rates in the streets and in terms of timing. However, some discrepancies appear between the measurements and the numerical results, mostly due to some topographical local uncertainties and to the capacities of the equations to model the complex flows in the crossroads.

Cities↗