Numerische Untersuchung von Skaleneffekten auf die Hydrodynamik in einem Buhnenexperiment

Groynes are widely used in hydraulic engineering and are challenging in terms of their effectiveness and suitability as a river engineering measure due to the complex flow conditions depending on the water level and groyne geometry. Physical modeling has been used in hydraulic engineering for around 130 years, combined with field measurements where necessary and more recently combined with numerical models, which also benefits the evaluation of groynes. However, errors can occur due to the scaling of physical models. In this study, groyne variants were investigated in a 1:1 experiment and in an experiment at a scale of 1:5. 3D numerical models of the experiments were created, calibrated and validated using measurements. Contrary to the modeled flow velocity, differences in the modeled turbulent kinetic energy were generally identified between the scales. These differences could also be found exemplarily in measurements. The differences were greater the lower the water level or the higher the groynes were. These findings indicate that the model scale is of great importance for physical modeling. The new hydraulic engineering laboratory at the University of Natural Resources and Life Sciences, Vienna is ideally equipped for large-scale experiments. A more detailed investigation of scaling errors in physical models of groynes and other measures in combination with improved numerical models is recommended in the future to investigate the causes and evaluate their effects on other aspects such as sediment transport, morphodynamics and ecology.