Author(s): Volker Weitbrecht; Nils Ruther
Linked Author(s): Nils Rüther, Volker Weitbrecht
Keywords: Laboratory experiments; Numerical modeling; CFD; Sediment transport; Drift wood; Flood protection
Abstract: In the Ettisbuhl river stretch of the Kleine Emme close to Lucerne, Switzerland, a drift wood retention area has been planned to remove at least 50% of the oncoming drift wood during flood events. A new hydropower station will be installed in the same area. The planned configuration has been tested with laboratory experiments. The model is equipped with a movable bed to reproduce unavoidable bed level changes in the expanding section, where incoming drift wood is diverted into the drift wood retention area. The laboratory experiments showed that sediment transfer processes lead to a reduced discharge capacity in the main stream and that flood safety can be improved using a parallel approach flow for the drift wood retention rack. In addition to the experiments, the flow field and sediment transport have been simulated with a 3D CFD model. The purpose of the simulation and the comparison to the measured data was to test the capabilities of the numerical code in such complex flow and to verify the development of the river bed.
Year: 2009