Publications

O Porto de Leixões, localizado na costa norte de Portugal, é um dos maiores do país, recebendo diariamentevários navios de grandes dimensões. Um dos principais postos de acostagem situa-se à entrada do porto e encontra-se sujeito à agitação marítima que é difratada pelo olhe principal de proteção do porto. Para avaliar dos movimentos induzidos no navio estacionado nesse posto de acostagem e as forças exercidas nas suas amarras e defensas pela agitação incidente, utilizou-se o modelo físico de Leixões, construído num dos tanques do LNEC. Neste modelo físico, encontra-se representada a envolvente do porto de Leixões, assim como a sua batimetria. O modelo do navio

An alternative to the energy matrix expansion, due to the increase of global electricity demand, is the renewable sea wave energy source, which has high energy potential. The Oscillating Water Column (OWC) converter is one of the most studied, although it is not yet used at commercial scale. Therefore, searching the optimal geometric configuration is fundamental to turn this device viable. This study proposes a numerical analysis of an onshore OWC for different slopes of chamber walls (from 40o to 90o) and equipped with a Wells turbine. Simulations of incompressible 2D flows are performed by means of the FLUENT® software, which is based on Reynolds-averaged Navier-Stokes (RANS) equations. The k-

The most studied device used for extracting wave energy is the Oscillating Water Column (OWC). In general, numerical simulations of these cases by means of models based on Reynolds Averaged Navier-Stokes equations adopt the Volume of Fluid method to deal with the free surface flow which is considered incompressible in both water and air. The aim of this study is to investigate the influence of the compressibility effect on the air inside the OWC chamber by the FLUENT® numerical model. A methodology is implemented, taking into account both water and air flows incompressible, but, at every instant, a pressure condition is imposed on the top boundary of the chamber to consider the compressibility effect. This pressure condition is based on an analytical equation that considers the isentropic transformation of the air and effects of Wells and impulse turbines. Results of compressible and incompressible numerical models are compared. The amplification factor, the root mean square of air pressure inside the chamber and OWC efficiency in relation to incident wave period, wave height and turbine characteristic relation are analyzed. Results show that air compressibility effects can diminish the predicted OWC efficiency up to about 20% in both Wells and impulse turbines.

In this study, a numerical analysis of the performance of two Oscillating Water Column (OWC) wave energy converters, at different front and back wall slopes, was carried out. The first device had vertical front and back walls and the second one had its wall slopes of 40° in relation to the horizontal plane. The FLUENT® numerical model, which is based on the Reynolds-Averaged Navier-Stokes (RANS) equations, was used. The Volume of Fluid (VoF) method was employed to take into account free surface flows. The case study comprised a 10 m deep flume with an onshore OWC at its end, equipped with a Wells turbine. A 2D hydrodynamic mathematical model was employed and a 3D air pressure effect inside the OWC air-chamber was considered. Analyses of the hydrodynamics behavior, fluid-structure interaction outside (run-up/down, reflected waves) and inside the chamber (free surface elevation, sloshing) and energy distribution (pneumatic extracted energy, reflected wave energy and energy losses) were conducted. Results showed that the device with inclined walls had the best efficiency in comparison with the other one. However, the latter showed lower variation in efficiency in the wave period range than the former.

The main objective of this study is to investigate differences of random incident waves from regular ones in performance of wave energy converters (WEC). A numerical analysis of an onshore oscillating water column (OWC) WEC is carried out by means of the FLUENT® software, which is based on Reynolds - Averaged Navier-Stokes equations. Analyses of the efficiency of an onshore OWC device with similar characteristics of the Pico

Atualmente, mais importante que assegurar a resistência de um aglomerado urbano a um eventual invasor, importa garantir a sobrevivência a catástrofes naturais das infraestruturas críticas que garantem a salubridade das condições de vida nesse aglomerado, a mobilidade dos habitantes e o abastecimento de bens essenciais. Em rigor, face ao carater aleatório destas solicitações, pretende-se que, uma vez terminadas essas solicitações extremas, eventuais estragos causados pelas mesmas não impeçam o restabelecimento, em tempo útil, das atividades normais da população. Nesta comunicação apresentam-se ferramentas e procedimentos para avaliação do risco associado a infraestruturas críticas com um viés para o controlo de cheias urbanas e de infraestruturas de transporte marítimo.

The current program of Systematic Observation of Maritime Works (OSOM+), under development at the National Laboratory for Civil Engineering (LNEC), is essentially applied to rubble mound breakwaters. The OSOM

HIDRALERTA is a forecast and early warning system for coastal and port regions capable of predicting emergency situations, as well as carrying out risk assessment. The system concentrates on evaluating wave overtopping and flooding scenarios. It uses offshore sea-wave and wind forecast data, as well as tide data, as input to determine wave overtopping at specific locations. The calculation of the mean overtopping discharge over a structure is made through artificial neural network (ANN) tools and/or empirical formulae, which are able to define the spatial distribution of the flow behind the structure.The HIDRALERTA system is composed of four modules developed in Open Source Web Technology, mainly using the Python Language. The Warning System can be configured and adapted for specific scenarios. The system has been successfully tested for the Port and Bay of Praia da Vitória, Terceira Island, Azores, Portugal, and is now under development and being implemented at the ports of Madalena do Pico and S. Roque do Pico.This paper describes the work carried out to date on the system and its application to these two ports in the Pico Island, Azores.

A set of scale-model tests carried out to enlarge the range of wave steepness values analysed in run-up, overtopping and armour layer stability studies, focusing on oblique extreme wave conditions and on their effects on a gentler slope breakwater

Mechanical constraints have a non-negligible influence in the motion of oscillating wave surge converter (OWSC) devices. The key novelty of this paper is a numerical simulation tool for OWSCs that does not neglect or significantly compromise mechanical constraints such as hydraulic power take-off (PTO) system, revolute joints and frictional contacts among components. The paper is aimed at presenting the key components of the numerical simulation tool and at validating it with laboratory data featuring an OWSC with mechanical constraints under regular and irregular waves. It is based on the implementation of the multibody solver of Project Chrono under the Smoothed Particle Hydrodynamics (SPH) model of DualSPHysics, where the SPH solver resolves the interaction between wave and flap and the multibody solver resolves the interaction between flap and mechanical constraints. Comparison between numerical results and experimental data show that the numerical simulation tool properly predicts the dynamics of the OWSC. Furthermore, in what concerns hydrodynamics of the near-flap flow, the computed and measured free-surface elevations and phase-averaged flow field show reasonable agreement. Once properly validated, the numerical simulation tool is then applied to study the influence of several mechanical constraints, PTO damping characteristics and flap inertia on the hydrodynamic of the OWSC. The viability of OWSC design solutions based on the developed numerical simulation tool is emphasised, in view of its performance in the test cases to which it was subjected.

An aerial monitoring system was developed for the maritime structures protecting the foundation columns of the airport infrastructure of the Madeira Island Airport, in the scope of research project MEGE, to complement the already existing monitoring program of visual observations. For the aerial monitoring of the berm breakwater, with about 770 m in length, a fast data acquisition system was envisaged. Imaging techniques acquired through a high-resolution camera coupled to an unmanned aerial vehicle (UAV) were used, which allowed for a very fast and efficient automated procedure, compatible with the difficult accessibility to the structure on the seaside. Point clouds corresponding to the breakwater geometry were obtained from the set of aerial images from the camera on board of the UAV, using photogrammetric techniques. In this paper, the two complementary parts of the monitoring of this structure are described and corresponding results are shown.

This paper aims to evaluate the impact of ships on fenders during the berthing process. Physical tests and numerical simulations with MOORNAV tool were performed with versions of the GulfStream ship in still water and under a set of different conditions. A comparative analysis was made between outputs of the two models considering specific conditions. The MOORNAV application resulted in a standard deviation from the physical model of 3% to 6% in relation to the maximum force exerted on each fender.

This paper aims to evaluate the impact of ships on fenders during the berthing process. Physical tests and numerical simulations with MOORNAV tool were performed with versions of the GulfStream ship in still water and under a set of different conditions. A comparative analysis was made between outputs of the two models considering specific conditions. The MOORNAV application resulted in a standard deviation from the physical model of 3% to 6% in relation to the maximum force exerted on each fender.

Neste trabalho, descreve-se a aplicação do programa OSOM+ às obras marítimas do Porto de Sines, em especial ao quebra-mar oeste. Assim, serão apresentados resultados de comparação entre as situações observadas em 2018 e 2020 no âmbito de inspeções visuais e com drone, mediante apreciação e análise de fotografias georreferenciadas, ortomosaicos, nuvens de pontos, modelos numéricos de superfície e perfis selecionados. É também ilustrada a forma como a aplicação e base de dados ANOSOM-WEB pode ser empregue quer durante as campanhas de observação, quer em gabinete. Conclui-se este trabalho com a apresentação das vantagens da recente atualização da metodologia e do que se julga ser a sua importância na tomada de decisões sobre a necessidade ou não de realizar obras de manutenção e/ou reparação nestas estruturas, ou similares.

Os mapas de risco costeiro, integrados em modelos de risco, são excelentes ferramentas de apoio à tomada de decisão no âmbito da gestão e proteção costeira em situações normais e de emergência [1], ajudando aproteger as populações e infraestruturas em risco de inundação costeira e galgamento oceânico proteger as populações e infraestruturas em risco de inundação costeira e galgamento oceânico.

SAFEPORT safety system aims at forecasting and alerting, on a regular basis, emergency situations regarding ships operation in port areas caused by extreme weather-oceanographic conditions. It uses forecasts provided offshore of the area under study of sea agitation, wind and tide. The characterization of the response of the free and moored ships at a berth is performed using the numerical package SWAMS. The system issue alerts, through danger levels associated with risk levels of exceedance of recommended values for movements and forces imposed on ship mooring systems. SAFEPORT can be adapted to any port. So far, it has been developed and adapted to three terminals of the port of Sines, where three different ships were simulated. This paper presents the developments made to date of the safety system, which includes tests performed in storm situations. The numerical models run every day, in real-time mode, in a computer cluster and the system provide forecast results for the next 72 hours. The results are disseminated on a web page and a mobile application in a variety of formats. It was concluded that the SAFEPORT safety system issued alerts according to the observed reality during the storm Dora. It has also been shown to be a computer tool for the optimization of ship mooring systems. The system is currently in testing and validation phase therefore, forecasts should be interpreted as indicative.

A autoridade portuária do arquipélago dos Açores, Portos dos Açores, SA, identificou a necessidade de dispor de um sistema de alerta precoce para os riscos associados à agitação marítima, nomeadamente os relacionados com os galgamentos costeiros e com os navios amarrados. No âmbito do Projeto ECOMARPORT, associaram-se com a Universidade dos Açores e o LNEC para o desenvolvimento de três novos protótipos do sistema HIDRALERTApara os portos de S. Roque do Pico, Madalena do Pico e Praia da Vitória. Os novos protótipos têm, para além da previsão de eventos de galgamento das proteções portuárias, a capacidade de prever esforços e movimentos de navios amarrados. As situações de emergência podem ser previstas, permitindo que as autoridades portuárias possam tomar medidas de mitigação para evitar a perda de vidas e minimizar os danos.

Early warning systems (EWS) are fundamental tool to reduce risks in coastal areas since they provide in advance the necessary information for the responsible authorities to mitigate the effects of possible emergency situation due to storms.

The case studies are Costa da Caparica coastal area and Ericeira port, both on the West Portuguese Coast.

The To-SEAlert project (Fortes et al. 2019) aims to include a set of tools/methodologies into the Early Warning Systems (EWS) HIDRALERTA, (Poseiro, 2019, Fortes et al., 2021, Santos et al., 2020, Zózimo et al., 2021, Ferreira, et al. 2021a) to make it more efficient reliable and robust.

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