Publications

This paper presents the analysis of the probability of occurrence of wave overtopping events as well as its consequences at the Port of Las Nieves in Agaete, Gran Canaria Island, with the evaluation of the resulting level of flood risk. The study has been conducted using a third-generation spectral wave model to reproduce wave propagation from deep to shallow water depths considering the associated mean sea level, and a neural network-based model, for estimating mean wave overtopping discharges. Results reveal that overtopping in the initial sections of the port, located in the port access area, is substantially higher than that associated with the cross-sections of the main body of the breakwater, so that control actions to reduce overtopping are required due to the important socioeconomic implications regarding the infrastructure inoperability.

Neste trabalho, descreve-se a aplicação ao porto e baía da Praia da Vitória, na ilha Terceira, Açores, Portugal, da metodologia de avaliação do risco de galgamentos em estruturas marítimas em desenvolvimento no LNEC, considerando duas ferramentas neuronais para cálculo dos galgamentos baseadas em resultados da aplicação de redes neuronais artificiais, nomeadamente a ferramenta NN_Overtopping2 e a Overtopping Predictor v1.1. Em particular, avalia-se comparativamente quais as implicações que a utilização de cada uma destas ferramentas tem em termos de número de eventos de galgamento e magnitude dos caudais médios galgados, bem como consequente grau de risco, para as 9 secções-tipo de estruturas marítimas estudadas no porto e baía da Praia da Vitória. O período de estudo é de 5 anos (2008 a 2012).

O galgamento de estruturas portuárias consiste na passagem de água sobre o coroamento da estrutura pela ação da agitação marítima e é um dos fenómenos com maior impacto na integridade da estrutura e na segurança da zona por ela protegida. O principal objetivo deste trabalho é estudar o galgamento num quebra-mar de taludes, com um importante muro cortina, protegido por um quebra-mar submerso. Em particular, pretende-se otimizar a geometria do quebra-mar submerso situado a barlamar do quebra-mar de taludes, no qual se pretende diminuir o galgamento.A estrutura marítima em estudo é o molhe norte do Porto de Leixões, em frente ao qual já existe um quebra-mar submerso na zona da cabeça. Pretende-se estender a zona do molhe protegida pelo quebra-mar submerso e, para tal, é necessário estudar qual a melhor geometria e posição a adotar para este quebra-mar.Para estudar a influência da geometria e da posição do quebra-mar submerso no galgamento do molhe norte, utilizou-se o modelo numérico IH2VOF. Simularam-se três condições de agitação regular, que diferem somente na altura de onda, e sete geometrias do quebra-mar submerso, que diferem da configuração original (a existente atualmente) em três características: a distância entre o quebra-mar submerso e o molhe, a cota de coroamento do quebra-mar submerso e a sua largura de coroamento.Com a realização deste estudo, para as condições de agitação consideradas, verificou-se que as características com maior impacto na redução do galgamento no molhe norte do Porto de Leixões são: o aumento da distância entre o quebra-mar submerso e o molhe e o aumento da cota de coroamento do quebra-mar submerso. O caudal médio de galgamento para as condições de agitação em estudo reduziu-se de um valor máximo de 0,71 l/s/m para a configuração original para 0,02 l/s/m em duas das novas configurações analisadas, ou seja, uma redução de 97% face à configuração original.

The susceptibility of bridge decks to vortex induced oscillations can b eaddressed through wind-tunnel testing. This paper considers the case of the Vila-Real Bridge, in the north of Portugal, which has the highest deck above ground (230m), among concrete-deck bridges cable-stayed in the central plane. It has a single-cell rectangular box girder with a wide top flange supported by regularly spaced inclined struts. Aeroelastic studies of this precise type of deck seem nonexistent in the literature.Results of sectional model tests are presented for a selection of three distinct angles of attack and three deck configurations, including a solution, alternative to the usual mitigation measures, that solved the susceptibility to vortex induced vibration of the deck and that has no relevant additional design or building costs.With the proposed approach, bridge designers may be able to relegate the use of sections with high aerodynamic performance

Wave-induced flow velocity and turbulence may cause scouring in the seabed around coastal structures depending on the wave climate and tidal water depth. A 3-D physical modelling study was conducted to investigate the possible causes of the sinking of two submerged coastal structures on the Santa Maria del Mar (SMM) beach, Spain. The experimental investigation was conducted by employing a Froude similarity law with a geometric scale of 1:20, and the submerged modular structure was subjected to different wave climates and tidal water levels. The combinations of the significant wave height and peak period were chosen from in-situ real wave conditions thatwere monitored during the sinking of the prototype structures. Linking and unlinking conditions for the modules in the structure were investigated in this study. The results show that the modules sank to approximately 48% of their height at the end of the tests with storm waves and semi-linking conditions of low water depth. Most of the experimental results were compatible with the prototype monitoring results. Tests with proper linking among themodules and testswith an appropriate gravel foundation resulted in a sustainable solution because they presented much less or almost no scouring and sinking.

Despite the simplicity of the geometry of the circular cylinders, the uniform flow around them is complex,since it may induce unsteady forces on structures associated with vortex shedding. This paper describes the study of two circular cylinders (the downstream one is elastically mounted in transversal direction) in tandem arrangement subject to bi-dimensional uniform laminar flows at low Reynolds numbers. The academic numerical model Ifeinco, which is based on the finite element method and uses a partitioned scheme that considers two-way interaction of fluid flow and structure, has been employed to the analysis.Firstly, both stationary cylinders in tandem arrangement for Re = 100 are analysed for center to center distance between the cylinders, L/D, from 1.5 to 6.0. Results of lift and drag coefficients and Strouhal number are compared with other numerical results and good agreement is found. Secondly, numerical results for L/D = 5.25, considering downstream elastically mounted cylinder, are analysed for Reynolds numbers ranging from 100 to 140. It shows that the resonance occurs for Reynolds numbers between 115 and 120 and the maximum dimensionless amplitude of oscillation is 0.721 for Re = 118.

Techniques based on artificial neural networks (ANNs) have been increasingly applied to predict emergency situations, such as extreme wave conditions, wave overtopping or flooding, and damage to maritime structures, in coastal and port areas. In this work, a fuzzy adaptive resonance theory with mapping (FAM) ANN was trained to predict the wave regime both inside and at the entrance to the Port of Sines, one of the major trade and economic gateways of the Iberian Peninsula, located on the Portuguese west coast. In situ measurements using pressure sensors, wave buoy data, and results from two numerical wave propagation models

The main goal of this paper is to develop a photogrammetric method in order to obtain arobust tool for damage assessment and quantification of rubble-mound armour layers during physicalscale model tests. With the present work, an innovative approach based on a reduced number ofdigital photos is proposed to support the identification of affected areas. This work considers twosimple digital photographs recording the instants before and after the completion of the physicaltest. Mathematical techniques were considered in the development of the procedures, enabling thetracking of image differences between photos. The procedures were developed using an open-sourceapplication, Scilab, nevertheless they are not platform dependent. The procedures developed enablethe location and identity of eroded areas in the breakwater armour layer, as well as the possibilityof quantifying them. This ability is confirmed through the calculation of correlation coefficients ineach step of the search for the more damaged area. It is also possible to make an assessment of themovement of armour layer units.

An investigation of the applicability of the SWASH model for wave overtopping estimation of a porous structure with a recurved wall was carried out. The results demonstrate the capability of SWASH to predict with good accuracy the mean overtopping discharges when compared to data from physical model tests. Also, detailed validation of the instantaneous wave overtopping shows a reasonable agreement.Whilst free surface is well represented without considering several parametrizations, even for one-layer mode, wave overtopping is very sensitive to any variation in numerical and physical parameters. Wave overtopping simulations are very sensitive to the non-linear Forchheimer coefficient,

This paper focus on the study of different methodologies for surveying two-dimensional scale models of a rubble mound breakwaters.Tests were conducted in one of the LNEC

Este artigo descreve os mais recentes desenvolvimentos do sistema SWAMS ALERT. O sistema consiste em quatro módulos: I - Características da agitação marítima; II - Navegação em áreas portuárias; III - Avaliação de Risco e IV - Sistema de Alerta. O sistema está a ser desenvolvido e implementado numa plataforma web totalmente interativa e amigável.O sistema SWAMS ALERT usa as características da agitação marítima medidas ou previstas para determinar os seus efeitos em termos de movimento vertical excessivo de uma embarcação em manobras que entra ou sai de uma bacia portuária ou em termos de forças em amarras e defensas, bem como de movimentos de um navio amarrado. Para isso, o sistema utiliza um conjunto de modelos numéricos. A comparação dos valores calculados das variáveis relevantes com valores máximos pré-definidos permite a avaliação em tempo real de possíveis situações de emergência ou quando a segurança das operações portuárias estiver em risco e emitir avisos às autoridades competentes; e ainda a construção de mapas de risco, considerando longas séries temporais de ondas de mar medidas ou previstas ou cenários predefinidos associados a alterações climáticas ou eventos extremos.Ilustra-se a aplicação deste sistema ao porto da Praia da Vitória.

The design of certain seawalls / breakwaters has often been required to achieve very low target overtopping discharges when these structures protect vulnerable infrastructure or activities. The balance between economically viable protection and performance requirements is often difficult to achieve without good knowledge on low overtopping. The paucity of data in this space and the high uncertainties associated with existing methods, increase the challenge. The occurrence of a low number of overtopping waves has the consequence that any test results are substantially more affected by the inherent variation of random waves, therefore more uncertain. The physical model test results presented hereafter were successful in obtaining low to very low overtopping discharge data. For low / very low overtopping, these test data present considerable scatter relative to the latest empirical prediction. A number of repetitions was performed for conditions giving very low overtopping discharges, which illustrated the inherent uncertainty associated with low overtopping.

Rubble mound breakwaters (RMB) are the most common maritime structures in Portugal. Their main goal is to reduce the action of waves on the sheltered area of the structure to achieve safety conditions for ships, people and harbour activities.To account and define the need for maintenance or repair works on such structures, it is necessary to evaluate its evolution along its expected lifetime. To predict damages that may occur in those structures and evaluate its importance in terms of structural safety and functionality, it is therefore of utmost importance to follow a monitoring program on such structures. For that purpose, a monitoring mobile tool to be used onsite by the observer would be very useful, adding in this way more efficiency to the existing traditional monitoring techniques used nowadays at LNEC, where visual, systematic, observations are made to attain relevant qualitative evaluation of those structures.Hence, a responsive WebGIS system was developed (Maia et al., 2017) for assisting the observation campaigns, enabling the introduction of photos and videos, their accurate georeferencing, the automatic evaluation of the current, and evolutive, structural state of the structure, and also the checking of physical characteristics of the structure and materials.Besides briefly describing the monitoring tool, this paper focuses primarily on demonstrating its application to a real case scenario of an inspection campaign to the RMB of Ericeira,Portugal, on the 20th of April 2017.

O LNEC tem implementado, desde 1986, um programa designado por OSOM (Observação Sistemática de Obras Marítimas) para quebra-mares de talude localizados em Portugal continental. Para armazenamento, consulta e análise da informação que vai sendo recolhida sobre os diferentes quebramares no programa OSOM, desenvolveu-se no LNEC a aplicação ANOSOM (Análise de Observação Sistemática de Obras Marítimas), a qual tem vindo a ser alvo de diversas atualizações, inclusivamente o manuseamento de nuvens de pontos provenientes de levantamentos dos quebra-mares com sistema de sondador multifeixe e/ou com a ajuda de UAV. Presentemente está em desenvolvimento uma aplicação Web a, ANOSOM_SIG, a qual virá a ser utilizada como interface da base de dados ANOSOM que inclui as funcionalidades de um Sistema de Informação Geográfica (SIG), transformando-se assim, numa ferramenta de gestão de risco em estruturas de proteção costeira e portuária.O objetivo desta comunicação é descrever a aplicação ANOSOM_SIG, bem como as suas funcionalidades até agora implementadas, apresentando alguns exemplos de aplicação.

This paper ilustrates lhe application of a non-linear shallow water numerical model, AMAZON, to study Oscillating Water Column Wave Energy Converters (OWC-WEC) inregrated in vertical breakwaters. This application has been performed within the scope of the research project DITOWEC - Development of an Integrated Tool for Numerical Modelling of Oscillating Water Cohumn Wave Energy Converters Integrated in Vertical Breakwaters. The main objective of DITOWEC is the development of an innovative integrated tool for numerical modeling of wave propagation from offshore to nearshore, of wave-structure interaction and of the complex nonlinear hydrodynamic and aerodynamic phenomena that occur in an OWC-WEC. This development is supported by field data from PICO power plant (Azores) and from two-dimensional experimental data, from physical model tests carried out at LNEC, which are used here for AMAZON calibration/validation. A sensitivity analysis on AMAZON parameters (grid resolution and momentum adjustment factor at vertical barrier) is presented and discussed, centered on wave height obtained near and inside lhe water chamber, amplification factor and phase lag. The obtained AMAZON results are encouraging though more tests are required for different water depths, vertical openings and incoming wave periods, allowing further calibration and validation of the momentum adjustment factor.

Com base em 10 anos de dados de temporais medidos na boía ondógrafo de Sines entre os anos 2001 e 2010, analisaram-se as características de diversos parâmetros da agitação, entre as quais as alturas de onda (significativa e máxima), o período médio e a direção de agitação. Em particular estudou-se a relação entre alturas de onda máxima e alturas de onda significativa durante condições de temporal, compararam-se as relações encontradas com as propostas na literatura e usualmente aplicadas no dimensionamento de quebra-mares verticais, e analisou-se a sua influência na estabilidade dessas estruturas. Verificou-se que os coeficientes de segurança calculados com base em valores de altura máxima registada são inferiores aos calculados com a relação proposta na literatura.

O dispositivo de aproveitamento de energia das ondas de tipo coluna de água oscilante (CAO) é um sistema que foi desenvolvido há já algumas décadas. Em condições de agitação marítima forte, pode ocorrer entrada de ar na câmara-de-ar do dispositivo, pela abertura submersa, comprometendo assim o seu rendimento. A colocação de uma parede vertical submersa, em frente ao dispositivo (UCAO), permite evitar este problema, mas altera o seu desempenho. Neste artigo, o modelo SPH é utilizado para uma primeira análise comparativa da hidrodinâmica dos dois dispositivos. Verifica-se que o factor de amplificação é fortemente condicionado pela dimensão da abertura submersa, reduzindo-se para uma abertura pequena, particularmente para os períodos de onda mais baixos. A amplitude da cava, na câmara de água e em frente ao dispositivo, é menor na configuração de UCAO que na CAO. É, assim, evidente que a UCAO reduz fortemente o risco de sucção de ar na câmara, embora reduza o factor de amplificação, quando comparada com a CAO.

The phenomenon of scour in the vicinity of coastal and harbour protection structures, wind farms, offshore platforms and marine outfalls is one of the causes associated with its collapse. During the design of such structures, the prediction of the maximum erosion depth located in the vicinity of the structure is of utmost importance, requiring, frequently, a validation by scale-model tests. The objective of this study is to validate the use of stereo photogrammetry in such tests. To accomplish this goal, two sets of tests were conducted: A stereo photogrammetric survey of a well-known shape molded in a sand box was carried out in order to infer on the accuracy of the technique when applied to a sand bed. The second set of tests consisted on the survey of the scour around a pile, using the stereo photogrammetric method as well as a bed profiler in order to compare the results obtained with both methods.

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A major objective of TRA LISBON 2022 Conference is to boost research and innovation capacity for the transport sector, throughout a full innovation cycle, from idea to market. Having this in view, the project

The demonstration area will be one of the main focus points of TRA LISBON 2022, presenting multifunctional spaces and being prepared to receive a large number of different types of on-site demonstrations (indoor and outdoor). On-line demonstrations will also be an option, allowing for the widest possible coverage of access for all the participants.The dedicated areas will allow for interactive demonstrations of technological innovations to be carried out by and for industry partners, researchers, and other stakeholders. Demonstrations are an excellent opportunity to introduce conference attendees in an engaging way, as well as to promote new contacts and promising business.

According to the CSA project plan, WP5.2 task objective is to organize technical tours that feature attractive and interactive showcases aiming at engaging participants into novel technologies for all transport modes and enabling stakeholders and their companies to disseminate and even sell their products and applications to all interested parties.

This report is part of HYDRALAB+ Work Package 10, which seeks to strengthen the coherence of experimental hydraulic and hydrodynamic research undertaken by the HYDRALAB+ partner organisations. It outlines the work carried out by Samui Design & Management Ltd, supported by HR Wallingford, in relation to the development of a data repository structure that can be adopted by participants of the HYDRALAB+ project.

Reliable prediction of wave run-up/overtopping and structure damage is a key task in the design and safety assessment of coastal and harbor structures. Run-up/overtopping and damage must be below acceptable limits, both in extreme and in normal operating conditions, to guarantee the stability of the structure and the safety of people and assets on and behind the structure. The mean-sea-level rise caused by climate change and its effects on wave climate may increase the number and intensity of run-up/overtopping events and make the existing coastal/harbor structures more vulnerable to damage.Accurate estimates, through physical modelling, of the statistics of overtopping waves for a set of climate change conditions, are needed. The research project HYDRALAB+ (H2020-INFRAIA-2014-2015) gathers an advanced network of environmental hydraulic institutes in Europe, which provides access to a suite of environmental hydraulic facilities. They play a vital role in the development of climate change adaptation strategies, by allowing the direct testing of adaptation measures and by providing data for numerical model calibration and validation. The use of physical (scale) models allows the simulation of extreme events as they are now, and as they are projected to be under different climate change scenarios.The enclosed dataset refers to the experimental work developed at LNEC within HYDRALAB+ and considers 2D damage and overtopping tests for a rock armor slope, with four different approaches to represent storms. Data of free surface elevation, overtopping and damage is presented.

The HYDRALAB+ project is aimed at strengthening the coherence of experimental hydraulic and hydrodynamic research undertaken across its partner organisations. This report is D10.2 of the HYDRALAB+ project, entitled

The HYDRALAB+ project is aimed at strengthening the coherence of experimental hydraulic and hydrodynamic research undertaken across its partner organisations. This report is D10.3 of the HYDRALAB+ project, entitled

This deliverable is related to task 8.2

Neste relatório inicial são apresentadas a arquitetura e as caraterísticas gerais dos protótipos do sistema de previsão, alerta e gestão de riscos causados pela agitação marítima para os portos de Madalena do Pico, São Roque do Pico e Praia da Vitória. Os três protótipos em desenvolvimento têm por base uma arquitetura semelhante, com características distintas, nomeadamente no que respeita à localização dos dados de base, às malhas computacionais utilizadas e às características físicas das fronteiras, tanto no plano horizontal (interface terra-mar), como no vertical (batimetria dos fundos). Caracteriza-se o layout geral dos portos, bem como a sua morfologia e operabilidade.

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