Evaluation of the influence of deck slope on green water loads using the wet dam-break approach

Studies on wave and structure interaction are essential to design safe and sustainable marine structures for various applications. Specifically, the occurrence of green water phenomenon in marine structures can result in significant hydrodynamic loads. However, no systematic analyses have been undertaken to assess the loads produced by water interacting with sloped decks, due to different types of green water events. This paper describes an experimental and numerical analysis to investigate the impact of deck inclination and length on the overall loads caused by green water on a fixed structure. Wet dam-break methodology was used to generate the green water events, while OpenFOAM software was used for hydrodynamic modelling. The investigation examines three kinds of green water situations, namely dam-break and plunging-dam-break with minor and significant hollows formed at the deck periphery. Validation of the numerical approach was carried out using the results from experiments obtained with a horizontal deck, considering water elevations and loads over the structure deck. Then, numerical simulations were performed to provide a systematic analysis on how the slope and length affect total green water loads. The total loads assessed were those acting perpendicularly on the deck and on a vertical wall that limits the deck length. Experimental results obtained from the three types of green water showed different patterns, mainly distinguished by the features of the breaking wave, the size of the air cavity formed at the edge of the deck, and different amounts of water over the deck. The numerical results show that negative deck slopes and longer deck lengths notably increase the water-on-deck peak loads, while positive deck slopes decrease the loading time. Two main peak forces were consistently seen throughout the majority of the time series data, with their appearance being influenced by deck pitching. Considering the case of a horizontal deck with a vertical wall as reference, and the incident flows of this research, it was discovered that negative deck slopes may increase the peak loads acting on the deck by approximately 150 % , and by five times more the ones acting on the wall. Further research is suggested to determine the maximum peak loads to be used for design purposes in different types of deck configurations. The simplified methodology described in this paper can enhance our understanding of the patterns of green water loads on inclined decks of