This paper gives a detailed description of the main hydrodynamic characteristics of different types of green water events occurring on a fixed structure in a series of experiments. High-speed video, at 250 fps, was used to capture the flow details from regular waves produced inside a wave flume. The green water events were classified according to their type and the results of the evaluation from the apparent and effective interaction features. The air cavities in the PDB (Plunging Dam Break) type events were almost spherical for longer waves. PDB with large, elliptical cavities, and HF (Hammer Fist) type events occurred with steeper waves. The highest wave front and bow run-up velocities were found in PDB and HF events, respectively. The size of the cavities in PDB events increases and becomes more elliptical for higher bow run-up velocities. The results of these experiments show that not all events can be treated in the same way as the DB (Dam Break) type events when designing structures or implementing models, as not all interactions with the deck happen immediately when the shipping water crosses the bow edge.

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The Atlantic and Pacific coasts of Mexico offer a variety of marine energy sources for exploitation. Although the Mexican government has made important efforts to reduce its dependence on fossil fuels, national participation in clean energies is still limited in terms of electricity production. This paper presents a practical theoretical assessment of marine energy sources around Mexico, with the aim of identifying potential zones for subsequent, more detailed, technical evaluations and project implementations. The energy sources considered are ocean currents, waves, salinity, and thermal gradients. Using global databases, the percentages of energy availability for the defined thresholds were computed to establish the prospective regions with the most persistent power availability. This approach proved to offer more meaningful information than simple averaged values. Moreover, some environmental and socio-economic factors to be considered for future ocean energy resource assessments in Mexico were also discussed. The results show that the wave energy potential is highest in the northwest of Mexico (~2–10 kW/m for more than 50% of the time), and that there is a constant source of ocean current energy off Quintana Roo state (~32–215 W/m2 for more than 50% of the time). The thermal gradient power is more persistent in the southwest and southeast of the country, where ~100–200 MW can be found 70% of the time. The salinity gradient energy is strongest in the southeast of Mexico. The practical approach presented here can be extended to perform preliminary resources assessments in regions where information is scarce.

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Green water occurs when an incoming wave exceeds the freeboard and propagates onto the deck of naval/offshore structures, such as floating production storage and offloading units and platforms. This water can affect the integrity of facilities and equipment that are installed on the deck, compromise the safety of the crew, and affect the dynamic stability of the structure. Traditionally, wave trains have been used to study the green water problem, which is a good approach to analyzing consecutive green water events. However, to carry out systematic studies that allow local details to be identified for different types of green water, an alternative method is to study isolated events generated by a single incoming wave. The purpose of this paper was to experimentally investigate the generation of different types of isolated green water events using the wet dam-break (DB) approach as an alternative to generating the incoming wave. Tests were carried out in a rectangular tank with a fixed internal structure. Different freeboard conditions were tested for two aspect ratios of the wet DB (h0/h1=0.40 and 0.6). Conventional wave probes were used to measure the water levels in the tank, and a high-speed camera was set to capture details of the generated green water events. The results demonstrated the ability of this approach to represent different types of green water, similar to those obtained with unbroken regular waves in barge-shaped fixed structures, including DB, plunging-dam-break (PDB) and hammer-fist (HF).

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Green water events may present different features in the initial stage of interaction with the deck of a structure. It is therefore important to investigate the evolution of different types of green water, since not all the events interact with the deck at the same time. In this paper, the evolution of three types of green water events (dam-break, plunging-dam-break, and hammer-fist) are studied. The water surface elevations and volumes over the deck in consecutive green water events, generated by incident [wave trains in a wave flume, were analyzed using image-based methods. The results show multiple-valued water surface elevations in the early stage of plunging-dam-break and hammer-fist type events. Detailed experimental measurements of this stage are shown for the first time. The effect of wave steepness on the duration of the events, maximum freeboard exceedance, and volumes were also investigated. Although the hammer-fist type showed high freeboard exceedances, the plunging-dam-break type presented the largest volumes over the deck. Some challenges for further assessments of green water propagation are reported.