Author(s): Emmanuel Mignot; André Paquier; Nicolas Rivière

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Keywords: 2D shallow water equations; experimental study; junction; numerical validation; supercritical flow

Abstract: During severe urban flooding, the surface flow can become supercritical near some crossroads if the slope of the streets reaches a critical steepness. The present study aims to validate the capacity of a code solving the two-dimensional shallow water equations to simulate the flows in a four-branch supercritical cross junction. An experimental study showed that five main flow patterns can be observed and are determined by the upstream flow characteristics as well as the slope of the channels. Computed and measured flows were compared on five detailed water depth fields and on more than 200 measured flow rate distributions. It appears that the flow rate distribution to the downstream branches and the flow characteristics, computed by the code using a set of reference parameters, compare well with the experimental data. Nevertheless, some discrepancies appear concerning the prediction of the location and of the thickness of the oblique jumps mainly because jumps are set on one cell in the numerical model. Furthermore, the flow patterns remain well predicted when altering the set of numerical parameters though the water depth field is slightly modified when changing the friction coefficients or the other parameters governing energy losses.

DOI: https://doi.org/10.1080/00221686.2008.9521918

Year: 2008