Publications

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Nowadays, renewable energy is a topic widely discussed in scientific community. Specifically wave energy attracts attention because it has a high energy potential distributed throughout the planet. Oscillating Water Column (OWC) wave energy converter is one of the most studied devices that have promising perspectives to be installed commercially. This study aims investigating the influence of chamber sizes and turbine characteristics dimensions of an OWC device located at the southern Brazilian coast is carried out. Numerical simulations for incident waves with period T = 7 s and 10 s and height H = 1.5 m, by using the FLUENT® model, based on the finite volume method (VFM) are carried out. Efficiencies for different chamber sizes and Wells turbine characteristic relations (kt) in each incident wave are determined. The highest efficiencies were obtained by a chamber with 5 x 5 m and kt = 530 Pa.s/m³ in the case of an incident wave with T = 7s (52%), and 30 x 30 m and kt = 15 Pa.s/m³ at T = 10s (65%).

Port terminals downtimes lead to large economic losses and largely affect the port

This paper describes the physical model, experimental setup and tests performed to study the motions and forces of a ship moored to the pier A at the Leixões oil terminal, following the breakwater

HIDRALERTA is a forecast, early warning and risk assessment system for port and coastal areas that uses measurements and estimates of sea-waves and water levels to evaluate overtopping/flooding events. The calculation of the mean overtopping discharge over a maritime structure is performed through artificial neural network-based tools and/or empirical formulae. The system is developed in open source software, mainly using the Python language. This paper presents the application of HIDRALERTA system to reproduce the hurricane Lorenzo conditions and impacts at Lajes das Flores port on October 2nd 2019, the most affected port in Azores. This hurricane was regarded as the strongest storm to hit Azores in 20 years. The system predicted the expected results for the hurricane wave characteristics, as well as overtopping discharge volumes. Further validation still need to be improved with the collaboration of the local authorities and the use of historical data.

Numerical models are useful tools to predict the effects of storms in coastal areas. The objective of this work was to simulate the effects of storms in São Pedro de Moel beach by using XBeach. The nearshore sea state was obtained by propagating offshore conditions using the SWAN model. The XBeach model was divided into two setups to analyse overtopping events and coastal evolution. Sensibility tests, calibration, and validation, using information from different storms, were performed for the different setups. The results from the overtopping simulation were compared against results from an empirical formula. The comparison showed lower values obtained with the empirical formula. The coastal evolution run point out to the necessity of having better field data before and after storms to improve the model setting and accuracy.

The assessment of damage evolution in scale model tests of rubble-mound breakwaters can be achieved by comparing eroded depths and volumes between consecutive surveys. This paper focuses on damage evolution of a model of a rubble-mound breakwater and on the novelty of the non-intrusive survey methodologies such as laser scanning and Time of Flight (ToF) techniques, based on point clouds, enabling the extraction of profiles and the calculation of eroded depths and eroded volumes. The final objective of this work is to evaluate the applicability of the estimation the number of displaced armour units, using a non-dimensional damage parameter based on the calculated eroded volume.The paper will also describe the experiments conducted under the RODBreak, a project sponsored by the HYDRALAB+ Transnational Access Program, in which a stretch of a rubble-mound breakwater was built at the wave-current basin of the Leibniz University Hannover (LUH) to assess the structure behavior. Four scan surveys were conducted using a Faro Focus 3D laser scan, as well as a ToF sensor. Those surveys were carried out before and after two test series, in order to evaluate the eroded volume and profile evolution.

Neste trabalho é efetuada a validação do protótipo To-SEAlert para o porto da Ericeira. Para a validação dos resultados do modelo SWAN foram utilizados os dados de duas boias situadas ao largo da Nazaré e para a validação das previsões do sistema de cálculo do grau de risco foram simuladas as depressões Elsa e Fabien (ocorridas em dezembro de 2019) e que foram responsáveis por fortes danos na cabeça do molhe do porto da Ericeira. Verificou-se uma boa concordância entre os dados das boias e os resultados do modelo SWAN, tendo no entanto o modelo reproduzido melhor a direção média e a altura significativa do que o período de pico. Relativamente aos valores de galgamento, os resultados obtidos na simulação das depressões Elsa e Fabien estiveram em concordância com os valores referidos na literatura como causadores de danos nas estruturas.

This work aims to determine the exploitable wave energy resource at six potential sites, located in the Azores, Madeira and Sines breakwater city harbours. For that purpose, the thirdgeneration wave model SWAN is used to estimate the sea-wave conditions over the last 40 years. Boundary conditions of the sea states and wind fields are provided by the climate reanalysis datasets (ERA5). Using those results as inputs to the SWAN model, the sea-states were propagated shoreward, in order to estimate and analyse the wave climate conditions in the regions of interest. By combining the average energy flux per unit-length of wave front and the probability of occurrence of each sea state, the average exploitable annual energy per unit length of wave crest can be computed. The variability of this energy flux is described, since it is of fundamental importance for the efficiency of the Wave Energy Converters (WEC).

Former investigations on wave run-up and overtopping of (impermeable and permeable) coastal structures aimed at quantifying the influence of oblique waves on mean overtopping discharge, water layer thickness and velocities by developing empirical formulas of a reduction factor for wave obliquity,

In 2017, the RODBreak experiment was conducted. The experiment aimed at characterizing wave run-up, overtopping and damage in rubble-mound breakwaters. The reason for these experiments was the huge impact that climate can have on maritime structures, particularly in rubble mound breakwaters. In fact, the forecast sea level rise associated with more frequent and severe storms will have consequences either on the increase of wave runup, wave overtopping or on damage on existent structures since they were not design for those extreme values. However, for those climate change scenarios, little is known about the actual failure probability of such structures.Within this framework, a stretch of a rubble-mound breakwater was built in a wave basin. Under extreme wave conditions, with different incident wave angles (from 40° to 90°), a total of 49 tests were performed. Each test had different testing parameters, such as significant wave height (Hs), peak period (Tp) and wave direction. Also, for each test, different types of measurements were considered. Incident sea waves were measured with 3 arrays of 6 acoustic wave probes each as well as with isolated acoustic wave probes and 5 Acoustic Doppler Velocimeters (ADV

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