Author(s): Jan Tillmann-Mumm; Mario Oertel
Keywords: Numerical modeling; 2D-Simulation; 3D-Simulation; Water Quality
Abstract: Numerical flow simulations represent a modern tool to determine flow depths and flow velocities in rivers and hydraulic structures. Nowadays, numerical 1D and 2D flow simulations are state-of-the-art measures to analyse hydraulic engineering flow phenomena. But also, numerical 3D CFD simulations become more important due to growing computing and processing capacities. The main aim of the present investigation is the comparison of numerical 2D and 3D results focusing on the flow situation in a small lake system in the city of Lübeck in northern Germany. The investigation area is part of a historically developed flow system, dated back to the Hanseatic history. The River Wakenitz is a side river of the River Trave, which is surrounding the world heritage city of Lübeck. Within the last centuries the system has been continuously developed until the present situation was reached. But low discharge amounts in the formed lake system lead to problems due to water quality and non-existing flow variations. To optimize the hydraulic system, ADCP measurements were performed to measure the bathemetry and to create a digital model of the lake system. This geometrical model will be used for numerical 2D simulations in HEC-RAS and 3D CFD simulations in FLOW-3D to analyse and optimize both, hydraulic and geometrical components.