Alex Sanchez from HEC has tested the HEC-RAS a high concentration dam-breach experiment to test some of the mobile bed with mobile bed sediment transport on one laboratory data set from Goutiere et al (2011) a "Dam-break flow on a mobile bed in an abruptly widening channel: experimental data."
The experiment staged a 0.25m clear water reservoir over a 0.1 m mobile bed (median grain size 1.72 mm) at a channel expansion (from a channel with of 0.25m to 0.5m).
They removed the dam in less than 0.1 seconds, releasing a pulse of water and sediment into the expansion zone.
Goutiere et al. (2011) measured water levels during the experiment at gages P1-P8 in the diagram below, and a final bathymetry to capture scour and deposition zones including cross sections C1 though C 9 in the diagram below.
The HEC-RAS model was constructed with the following parameters:
Resolution: 5 x 2.5 cm
Manning’s n: 0.02 s/m1/3
Single grain class
Diameter: 1.72 mm
Transport potential: Wu et al.
Fall velocity: Soulsby
Hindered settling: Richardson and Zaki
This modeling approach yielded the following fluid depth time series at the gages (red) plotted with the measured values (blue).
After the simulation, the following cross sections were extracted at the end of the HEC-RAS mobile bed simulation and compared with the cross sections measured at the end of the experiment.
