A series of two-dimensional (2D) model tests were performed to investigate loads acting on a new artificial block (Starbloc) within a breakwater during regular waves. This block is designed as an interlocking single-layer armor block and is recommended to be placed using a regular placement pattern. Water-particle velocities in the vicinity of the armor layer were measured for several wave heights and wave periods with a laser Doppler velocimeter. A new formula is proposed concerning velocity parallel to the slope in relation to the maximum runup/rundown level. Wave force measurements were carried out on an equipped block placed below still-water level (on the armor slope). The hydrodynamic forces acting on the unit, and the corresponding force coefficients, were shown to be highly dependent on wave breaker characteristics. All the tests were undertaken with regular waves in order to fulfill a wave-by-wave analysis of the velocities and loads more easily.

The EU H2020 MaRINET2 project has a goal to improve the quality, robustness and accuracy of physical modelling and associated testing practices for the offshore renewable energy sector. To support this aim, a round robin scale physical modelling test programme was conducted to deploy a common wave energy converter at four wave basins operated by MaRINET2 partners. Test campaigns were conducted at each facility to a common specification and test matrix, providing the unique opportunity for intercomparison between facilities and working practices. A nonproprietary hinged raft, with a nominal scale of 1:25, was tested under a set of 12 irregular sea states. This allowed for an assessment of power output, hinge angles, mooring loads, and six-degree-of-freedom motions. The key outcome to be concluded from the results is that the facilities performed consistently, with the majority of variation linked to differences in sea state calibration. A variation of 5–10% in mean power was typical and was consistent with the variability observed in the measured significant wave heights. The tank depth (which varied from 2–5 m) showed remarkably little influence on the results, although it is noted that these tests used an aerial mooring system with the geometry unaffected by the tank depth. Similar good agreement was seen in the heave, surge, pitch and hinge angle responses. In order to maintain and improve the consistency across laboratories, we make recommendations on characterising and calibrating the tank environment and stress the importance of the device–facility physical interface (the aerial mooring in this case).

This dataset contains 2-dimensional wave tank testing data for a wave-driven rotating hydrofoil model. The model tested is composed of one or two hydrofoils rotating around a horizontal axis, perpendicular to the wave direction. The model was tested in a range of regular and irregular seas. The data contains measurements of the model in the wave tank including; wave measurement, rotor position, forces on the hydrofoils, and torque on the power take off. This data is the first of two sets of wave tank data generated for the LiftWEC H2020 research project. This first set consists of results for the device tested in 2D, while the second set will contain results for tests conducted in 3D. "LiftWEC Deliverable D4.3 Report on 2D experimental testing dataset" describes this dataset and for a complete description of the test campaign, readers are directed to "LiftWEC Deliverable D4.4. Report on physical modelling of 2D LiftWEC concepts "

The new interlocking concrete armour unit, 'Starbloc (R)', has been developed for coastal protection purposes. This compact armour unit consists of three legs' and two 'noses'. The design is based on finding an optimized placement on the slope with at least three contacts, which is self-stable under the own unit weight. 'Shipshape placement' on a single layer is recommended on steep slopes like 3V: 4H. 2D hydraulic model tests are performed to investigate the hydraulic stability and hydraulic performance of this new unit. The model tests are performed with irregular waves to observe the behaviour of the structure, applying JONSWAP spectrum with a peak enhancement factor gamma = 3.3. Based on hydraulic model tests, the results demonstrate a high hydraulic stability for the interlocked individual units (N-S = 2.9), despite of a satisfactory level of overtopping performance (gamma(r) = 0.45). Global damage (extraction of group of units) on very dense armour placement highlights the importance of considering a minimum porosity, 34%, inside the armour layer (surface) instead of a mean value (volume).

Using Underwater Imagery as a Complementary Tool for Benthos Sampling in an Area with High- Energy Hydrodynamic Conditions Underwater imagery is increasingly being used in the description of communities and habitats, as a tool to aid in the designation and management of marine protected areas. Here, we developed an underwater imagery system to monitor the seafloor and benthic communities in the Raz Blanchard (Aldernez Race), an area in the English Channel characterized by high-energy hydrodynamics. Despite the difficult conditions of acquisition, the underwater images highlighted the heterogeneous nature of the seabed in the Raz Blanchard. In this way, underwater imagery is a useful tool in providing additional information to standard benthic observations, particularly for the description of sessile epifauna and benthic landscapes. This system is flexible, robust and simple enough to be used in coastal and offshore areas, and is suitable as a complementary tool in benthic surveys to monitor the status and changing trends of seabed fauna and could be applied in future surveys.

Tidal bores are believed to induce significant sediment transport in macrotidal estuaries. However, due to high turbulence and very large suspended sediment concentration (SSC), the measurement of sediment transport induced by a tidal bore is actually a technical challenge. Consequently, very few quantitative data have been published so far. This paper presents SSC measurements performed in the Sée River estuary (Mont-Saint-Michel Bay, northwestern France) during the tidal bore passage with direct and indirect (optical) methods. Both methods are calibrated in laboratory in order to verify the consistency of measurements, to calculate the uncertainties, and to correct the raw data. The SSC measurements coupled with ADCP velocity data are used to calculate the instantaneous sediment transport (qs) associated with the tidal bore passage (up to 40kg/m2/s).

Since the end of the Little Ice Age (LIA), Svalbard glaciers have undergone a net retreat in response to changing meteorological conditions. Located between 76°N and 80°N, western Spitsbergen has seen a climatic transition from a glacial to a paraglacial system. On the northern shore of the Brøgger Peninsula (northwest Spitsbergen), the average temperature increased by 3 °C between 1965 and 2015, and cold-based valley glaciers have retreated more than 1 km from their LIA limits. This rapid deglaciation has exposed large areas of glacigenic sediments being easily reworked by runoff. This has led to the formation of extensive glacier-river delta systems and coastal progradation. Post-LIA coastal progradation and formation of new landforms in Kongsfjorden have been controlled predominantly by substantial availability of glacial sediment. A combination of aerial photographic and field data has been employed to estimate the post-LIA evolution of coastal sandur deltas and their submarine parts (named here “prodeltas”). The data set reveals that delta shoreline advance could have reached around 5 m/year. between 1966 and 1990 for the most energetic delta of Austre Lovenbreen, and around 4 m/year between 2011 and 2014 for the most energetic delta of Midtre Lovenbreen. The prodeltas registered a net growth from 2009 to 2012: the biggest, located in the prolongation of deltas of Austre Lovenbreen, measured 1033 m in length in 2009 and 1180 m in length in 2012. This substantial amount of sediment supplied in the fjord has an impact on the fjord ecology, especially on the benthic ecosystem.

Resume : La pose de blocs artificiels necessite une etude economique prenant en compte, d'une part, l'accroissement du cout de construction de la digue en raison du grand nombre de blocs qui doivent etre utilises et, d'autre part, l'augmentation des couts de pose et de reparation de la digue dus aux contraintes associees au placement de blocs elances et/ou fortement imbriques. La methode de pose est un parametre important qui influence la densite de pose des blocs par unite de surface, et donc la porosite surfacique et volumique de la carapace, consequences sur la Dans ce papier, nous presentons deux manieres differentes de considerer les porosites au sein de la carapace et ainsi d'examiner l'evaluation de ce parametre en termes de performances et stabilite. Si la porosite volumique est relativement aisee a determiner en modele physique, ce n’est pas le cas de la porosite surfacique. C’est pourquoi nous avons opte pour une representation virtuelle en trois dimensions a l'aide d'un logiciel DAO. Cette analyse aide a mieux comprendre l'influence de la porosite sur les phenomenes hydrauliques au sein de la carapace et donc les consequences sur la stabilite globale de l’ouvrage de defense. Mots-cles : Carapace – Densite de pose – Digue – Pose de bloc – Porosite – Porosite surfacique – Porosite volumique – Performance hydraulique – Ouvrage de defense