Author(s): Anuel Mignot; Andre Paquier; Nicolas Riviere
Linked Author(s): André Paquier
Keywords: Junction flow; Supercritical flow; Numerical simulation; Experimental study
Abstract: Four typical supercritical flows have been studied experimentally in a four-branch channel intersection. The water depth field of each flow configuration was measured on the physical model and then compared to the water depths computed with a 2-dimensional shallow water equation model using four different mesh densities. This comparison shows that, for all the meshes, the model is able to capture the main observed flow structures: oblique and normal hydraulic jumps, eddying on the downstream corner and deflection planes. Nevertheless, some discrepancies occur concerning the exact locations, shapes and intensities of these structures. Besides, a statistical analysis was performed in order to compare precisely the measured water depths and the computed water depths interpolated on the measurement grid. It appears that the water depth prediction quality depends mainly on the capacities of the code to simulate the width and angle of the measured oblique jump. Furthermore, it was shown that the use of a coarse mesh does not permit to capture the local high water depth zones and that the interpolation of the numerical results using this mesh density on the measurement grid tends to smooth the predicted flow. Finally, we observed that the average standard deviation of the measured water depths is of the same order of magnitude as the root mean square error between computed and observed water depth fields for all the configurations.
Year: 2005