The aim of this paper is to define a simple and useful formula to predict wave transmission for a common type of floating breakwater (FB), supplied with two lateral vertical plates protruding downward, named π-type FB. Eight different models, with mass varying from 16 to 76 kg, anchored with chains, have been tested in the wave flume of the Maritime Laboratory of Padova University, under irregular wave conditions. Water elevation in front and behind the structure has been measured with two arrays of four wave gauges. Our starting point for the prediction of wave transmission was the classical relationship established by Macagno in 1954. His relationship was derived for a box-type fixed breakwater assuming irrotational flow. Consequently, he significantly underestimated transmission for short waves and large drafts. This paper proposes an empirical modification of his relationship to properly fit the experimental results and a standardized plotting system of the transmission coefficient, based on a...

This note presents the Seabreath wave energy converter, basically a multi-chamber floating oscillating water column device, and the lumped model used to size its chambers, the ducts and the turbine. The model is based on extensive testing carried out in the wave flume of the University of Padova using fixed and floating models with a dummy power take off and indirect measurement of the produced power. A map with the available energy in the Mediterranean Sea is also proposed, showing possible ideal application sites. The Seabreath is finally dimensioned for a quarter scale test application in the Adriatic Sea, with a 3 kW turbine, and a capacity factor of 40%.

This paper discusses the key aspects of the recent Coastal Plan of the Veneto Region (IT). Its aim is to propose a single mitigation strategy for coastal erosion that is valid for the whole Veneto Region, and possibly elsewhere, as well as a method to assign a priority level to any action. The suggested mitigation action against erosion depends on urbanization level, beach width, as well as cross-shore and long-shore sediment transport. The criterion used to give a priority level to mitigation actions is based on a vulnerability index that takes into account erosive tendency, existing coastal flooding hazards, coast value, environmental relevance, tourist pressure, urbanization level, the presence of production activities, and cultural heritage. A sample case featuring the littoral of Rosolina is also provided and includes a site description, the sediment budget, critical issues and possible mitigation measures.

This paper aims at evaluating the wave overtopping discharge over the pavement of “Piazza S. Marco” (Venice) in order to select the best option to mitigate the risk of flooding of the Piazza and to protect the monuments and historic buildings, e.g., the “Basilica S. Marco”. In fact, the MO.S.E. (MOdulo Sperimentale Elettromeccanico) system is designed to keep the water level below a certain value, for the safety of the lagoon, but it does not guarantee the defence of the Piazza, where flooding is still possible, being its pavement locally much lower than the maximum expected water level. To completely defend the Piazza, specific additional works are planned to prevent the back-flow through the natural drainage system (now the primary pathway) or by filtration or by overtopping. This paper investigates on the overtopping mechanism, under conditions compatible with a fully operational MO.S.E. system, through 2-D experiments. The pavement of the Piazza is gently sloping towards the masonry quay which, in some parts is formed by 5 descending steps, and in some other parts, is just a vertical wall. Close to the “Marciana” Library, a critical part is present, with a slightly lower crest freeboard. In total, three cross-sections were examined in the 36 m long wave flume of the Padova University. The test programme includes 10 irregular wave attacks and three different water levels. The test results differ considerably from the results of the available formulas, since the investigated cross-sections by far exceed their range of applicability. The presence of the steps affects only the reflection coefficient rather than the overtopping discharges. In general, if the waves incident to the Piazza are higher than 40 cm, which is a possible scenario, some other adaptation works must be considered, such as the pavement rise, temporary barriers or the reduction of the waves impacting the quay through, for instance, floating breakwaters.

In recent years, marine flooding and its impacts have become a question of growing interest, since coastal areas are the most heavily populated and developed land zones in the world. This paper presents a rapid tool for mapping at regional scale the hazard associated with coastal flooding due to overflow. The tool merges a recently developed numerical model that solves a simplified form of the Shallow-Water Equations and is suited for Graphic Processing Unit (GPU) acceleration, with a Level II reliability method that allows producing hazard maps of inland flooding propagation. The procedure was applied to two stretches of the Venetian littoral, i.e., Valle Vecchia and Caorle, located in the northern Adriatic Sea. The application includes the site descriptions and the resulting hazard maps that show the probability of failure in each point of the coast for a given inland inundation level.

In view of a potential design of a 2 kW small scale prototype of a wave energy converter named Seabreath, the dimensioning of the power take off, generator and relative electrical equipment is under investigation. This note presents an innovative research focusing on a holistic description of the behaviour of this device. Within a Marinet application (FP7 Research Infrastructure Action) named “Multi-chamber oscillating water column device for harvesting Ocean Renewable Energy” (MORE), electrical experiments have been carried out in the “hardware in the loop” test bench in Tecnalia laboratory, Bilbao, in order to test different control strategies. For these experiments, the Electrical and hydrodynamic response need to be fully coupled. The note describes how the available hydrodynamic model of the Seabreath has been modified to be coupled to the new electric experiments. Since the electrical tests are being used to calibrate an electrical numerical model, the procedure depicts an innovative and complete type of wave-2-wire model of a wave energy converter.