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Flow and Turbulence over an Estuarine Dune − Large-Scale Flume Experiments
No full textBedforms, such as dunes, are found in large parts of estuaries and coastal areas. Dunes influence hydrodynamics and sediment transport in the flowing water by causing flow resistance, whereby flow energy is dissipated. The characteristics of flow over dunes are complex and vary depending on the dune shape. They have rarely been studied for estuarine dunes in particular, although a precise knowledge of the hydrodynamic processes is important, e.g. for a correct representation or parameterization in mathematical hydrodynamic models. Therefore, we conducted the first flume experiments over a typical estuarine dune. The experimental setup allowed for studying flow over a dune on a large scale and in a high level of detail. High-frequency measurements using Acoustic Doppler Velocimetry (ADV) were carried out on a 1:10 scaled experimental setup with a fixed model dune in a closed-circuit flume. Results show that over the steep portion of the dune lee side, a flow separation zone with a recirculating flow cell and a turbulent wake develop. Compared to values reported for triangular and river dunes, a longer flow separation zone (6.5 times the height of steep portion) and a downward oriented, shorter wake (5.5 times the height of the steep portion) were found. The high-quality experimental dataset including the flow velocity timeseries is freely available at [[https://doi.org/10.48437/02.2021.K.9900.0001 https://doi.org/10.48437/02.2021.K.9900.0001]](Bundesanstalt für Wasserbau 2021) and can be used for further studies, e.g. on the dissipative effect of dunes, or as validation data for laboratory experiments and mathematical models. Overall, we give indication for the need to study hydrodynamic processes related to estuarine dunes in more detail and we provide a full description of the experimental setup and the complete collected dataset to support and facilitate the needed further research
Statistische Analysen der Scherfestigkeit, Index- und Kompressibilitätseigenschaften glazilimnischer Sedimente in Norddeutschland
No full textDer Tagungsband "Vorträge der Fachsektionstage Geotechnik - Interdisziplinäres Forum 2023, Congress Centrum Würzburg, 12. - 13. September 2023" erscheint im Open Access und ist hier kostenfrei abrufbar: https://www.dggt.de/index.php?option=com_content&view=article&id=397%3Atagungsband-fstg&catid=45%3Apublikationen&Itemid=6
