Dambreak generator for the Large Wave Flume (GWK+)

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In experimental hydraulic and coastal engineering, dam-break gates are used to create a range of different flows. For this purpose, a wave channel is divided into two sections - in one section the water is impounded, while the other section is kept dry or has a significantly lower water level. With the help of a controlled, very fast opening process of the dam-break generator, different hydraulic phenomena, such as dam-break flows representing flash floods, bores as well as surge and sump waves can be controlled and systematically investigated. In addition to classical wave machines (e.g., piston type with vertical wall), dam breach generators expand the portfolio of hydraulic facilities to include other pioneering research opportunities. The dam-break generator applied for here will be used in the Large Wave Flume+ of the Coastal Research Center. A 4.9 m wide and 3.8 m high dam-break generator, which can be inserted into existing recesses for bulkhead placement, is planned for a functional generation of dam-break waves taking into account the scales and dimensions of the Large Wave Flume+. A maximum opening speed of about 1 s to the target height at the lower edge of the gate to the bottom of the channel of 1.5 m (1.35 m flow depth plus 0.15 m reserve height) creates an almost ideal dam-break flow during the rapid opening, which will serve three lines of research. The type of dam-break flow allows (1) the study of fluid-structure interaction between extreme flow events and buildings in terms of loading during flash floods, tsunami, or wave overtopping events, up to and including progressive collapse, (2) the generation and use of sunk (negative) and surge (positive) waves with a view to natural loading of banks and revetments due to ship waves, and (3) the study of scour and erosion development during transient flow events, with and without the influence of infrastructure elements such as bridges or abutments. The flow depths and velocities enabled with the dam-break generator will be unique, especially when combined with the large width that the dam-break gate will close off in the Large Wave Flume+. Existing research with dam-break flows is most often influenced by scale effects, which, however, can be significantly reduced or even entirely prevented by the achievable length scales in the Large Wave Flume+.