Laboratory technologies III

The decomposition of the water level into incident and reflected wave components is usually a necessary step in numerical or flume studies, as most design variables (overtopping, run-up) are linked to the incoming wave characteristics. Thus, utilizing an appropriate wave reflection analysis is critical for the analysis of such experiments. To this end, scaled experiments with a model salt marsh were carried out at the flume of the Hydraulic Engineering lab of the Delft. Two SICK LMS511 lidar laser scanners (LS) were used to record a dense grid of water levels along the wave flume. At the conference, we will showcase our findings by comparing the results of three wave reflection analyses applied on the LS data, in terms of incoming and reflected wave characteristics, as well as spectrum transformation, for a range of hydrodynamic conditions and geometrical set-ups.

Single layer randomly placed armour units are used in many rubble mound breakwaters around the world. For these armour layers, breakage of armour units due to rocking could be a major damage mechanism, but no good methods exist to evaluate and quantify rocking. The aim of the study is to quantify the rocking impact velocities for irregularly placed single layer armour units. This study utilizes embedded Rocking Sensors to obtain the first measurements of rocking impact velocities of single layer armour units. More generally, the paper will shows how novel measurement techniques can be used for the investigating the stability of single layer armour layers.

The capabilities and performance of the newly built wave generation and passive absorption system in the Coastal & Ocean Basin (COB) wave tank are investigated. Together, both systems are designed to achieve high-quality wave fields inside the measurement volume of COB. An assessment of the accuracy of the generated wave fields is carried out based on measurements obtained during two experimental campaigns, and the results will be presented at the conference.

SEABIM® is a patented scan to BIM process that can generate a reliable and complete 3D model of a rubble-mound breakwater precast protective layer (Xbloc®, Accropode™, Core-loc™ etc.). Using computer vision techniques, the known 3D shape of the Concrete Armour Units is detected in a high-resolution point cloud, which allows to obtain their position and orientation. By superimposing 3D models produced from different scans, the movement of each block can be computed.
This tool has been applied to numerous real-scale projects since 2019 both in the monitoring of newly built infrastructures and in the asset management phase. Breakwater physical models in laboratories, in wave flumes or basins, also require monitoring the movement of reduced-scale blocks between each wave series. With SEABIM this movement can be computed with accuracy for each block, allowing for a consistent evaluation of the armour layer response to wave loads.