Publicações

Nowadays, the use of RANS-based models for simulating numerical wave flumes and studying coastal engineering structures is common and allows investigating accurately phenomena that occur in current/wavestructure interactions. Comprehension of energy transformations in these processes can support designers tooptimize the system. In this study, a methodology to evaluate the terms of the energy rate balance in coastalengineering problems is developed. The methodology is applied to the propagation of regular waves in numericalwave flumes, onshore oscillating water column wave energy converter integrated into a vertical breakwater, andtwo types of rubble-mound breakwaters. The direct determination of the energy rate due to viscous and urbulencelosses and the porous resistance in rubble-mound breakwaters are carried out by time integration insidethe computational domain. Besides, the reflected and transmitted energy rates in the flume are calculated bymeans of this methodology, instead of the standard gauge methods, commonly used in physical and numericalflumes. Complementary, studies may be carried out for random incident waves and the methodology can beapplied to 3D wave tanks.

The evaluation of damage progression caused by wave action on physical models of rubble-mound breakwaters can be accomplished through two types of methods: quantifying the movements and falls of the resistant armor elements by visual inspection (the traditional, classical method) or determining the eroded volumes and depths between consecutive surveys of armor layers using sensors and photogrammetric methods (3D scanning methods). Of the latter, one may use techniques such as the so-called "Kinect", "Photogrammetry" and "LiDAR". The end-product of these techniques is, among others, point clouds, which allow obtaining three-dimensional surface models. In this paper, four of the latter techniques (3D scanning methods) are briefly described, and a comparison is made between them regarding their usability in current tests, their advantages and disadvantages, among themselves for a study case of the physical 3D model of the Ericeira breakwater. In evaluating survey quality across the four methods, RMSE (root mean square error) was employed to align obtained point clouds with ground control points (GCP). Notably, Photogrammetry, Kinect, and Azure techniques showed excellent RMSE values. Conversely, the LiDAR-derived-method cloud, using a smartphone with LiDAR sensor and 3dScanner app, fails to yield acceptable and accurate results for the research objectives of this paper.

Data of wave dissipation over vegetation fields was collected from laboratory flume experiments, fordifferent vegetation and wave conditions. An analytical model and a numerical model are applied to estimatethe wave dissipation obtained in the experiments, through the calibration of the bulk drag coefficient (CD).Results and conclusions will analyse and compare each model behaviour and obtained CD values.

Downtime of port terminals results in large economic losses and has a major impact on the overallcompetitiveness of ports. EarlyWarning Systems (EWS) are an effective tool to reduce ports

Coastal hazards such as flooding and erosion can cause large economic and human losses. Under this threat, early warning systems can be very cost-effective solutions for disaster preparation. The goal of this study was todevelop, test, and implement an operational coastal erosion early warning system supported by a particularmethod of machine learning. Thus, the system combines Bayesian Networks, and state-of-the-art numericalmodels, such as XBeach and SWAN, to predict storm erosion impacts in urbanized areas. This system wasdeveloped in two phases. In the development phase, all information required to apply the machine learningmethod was generated including the definition of hundreds of oceanic synthetic storms, modeling of the erosioncaused by these storms, and characterization of the impact levels according to a newly defined eerosion iimpactindex. This adimensional index relates the distance from the edge of the dune/beach scarp to buildings and theheight of that scarp. Finally, a Bayesian Network that acted as a surrogate of the previously generated informationwas built. After the training of the network, the conditional probability tables were created. These tablesconstituted the ground knowledge to make the predictions in the second phase. This methodology was validated(1) by comparing 6-h predictions obtained with the Bayesian Network and with process-based models, the latestconsidered as the benchmark, and (2) by assessing the predictive skills of the Bayesian Network through theunbiased iterative k-fold cross-validation procedure. Regarding the first comparison, the analysis considered theentire duration of three large storms whose return periods were 10, 16, and 25 years, and it was observed that theBayesian Network correctly predicted between 64% and 72% of the impacts during the course of the storms,depending on the area analyzed. Importantly, this method was also able to identify when the hazardous conditionsdisappeared after predicting potential consequences. Regarding the Regarding the second validationapproach, second validation approach, the k-fold cross-validation procedure was applied to the peak of a set ofvarying storms and it demonstrated that the predictive skills were maximized (63%

This paper investigates the influence of sea severity and mooring line pretension configuration on the operabilityof a moored vessel at a modified berthing site inside a port. A physical model was constructed to replicate thenew layout of the port of Leix

A wave flume is used to study a scaled model of a stepped bottom dual-chamber Oscillating Water Column (OWC) installed onshore. Compared to traditional single-chamber OWCs, the use of dual-chambers is expected to widen the range of sea states in which the OWC is more efficient, and the step, in front of the first chamber, boosts the capturing energy capacity of the device. The Power Take-Off (PTO) system is modelled as an air opening in the pneumatic chambers. Several experiments combining regular incident waves and PTO damping conditions are performed. Results of the amplitudes of the free surface elevations inside the chambers show that the device can amplify the incident wave amplitude up to 1.57 times in chamber 2. Results of the primary efficiency show that the device is highly dependent on the PTO damping characteristics and can reach around 40% for a wide range of wave periods. Results of the reflection analysis show that the reflection coefficient is also dependent on the PTO damping characteristics but remain lower than 0.6 for all the studied cases. Sloshing phenomenon (mostly in the cross-section direction) was observed for a wavelength close to the cross-section dimension, impacting negatively on the device pneumatic performance.

Laboratory experiments of wave propagation over rigid and flexible vegetation fields, with the same configurations, were conducted to understand the effect of vegetation flexibility on the drag coefficient (CD). The direct method and the least squares method (LSM), based on force and flow measurements, are applied to calculate the CD in the experimental conditions. The formulations of both methods are extended to estimate the CD for flexible vegetation cases. A video analysis was performed to account for the swaying motion. Typically, wave dissipation is lower for flexible than for rigid vegetation of the same configuration, under the same flow condition. Therefore, a proportional effect in the corresponding CD results, obtained from common CD calibration to wave dissipation without considering vegetation motion, is usually observed. However, the present results show that although the wave dissipation was 34% lower for flexible relative to rigid vegetation, the respective CD values were close. CD estimations considering vegetation motion and inertia suggest that CD of flexible vegetation was up to 13% higher relative to rigid vegetation. Accounting for inertia reduced the CD for rigid vegetation up to 7%, while raised the CD for flexible vegetation up to 13%.

Aquatic vegetation in the littoral zone plays a crucial role in attenuating wave energy andprotecting coastal communities from hazardous events. This study contributes to the developmentof numerical models aimed at designing nature-based coastal defense systems. Specifically, a novelnumerical application for simulating wave

Neste trabalho, descreve-se a aplicação ao porto da Praia da Vitória, na ilha Terceira, Açores, Portugal,da metodologia de avaliação do risco de galgamentos em estruturas marítimas em desenvolvimento no LNEC.Em particular, avalia-se a influência da variação do nível de maré na caracterização da agitação marítima e asconsequentes implicações na determinação do risco de galgamentos.Esta metodologia é constituída por três etapas: a caracterização da agitação marítima, a determinação dosgalgamentos sobre as estruturas e a avaliação do risco de galgamentos.A caracterização da agitação é feita com recurso a modelos numéricos de propagação de ondas. Utilizandoos resultados do modelo de previsão de larga escala WAVEWATCH III como dados de entrada para os modelosregionais de propagação de ondas, modelos SWAN e DREAMS, é caracterizada a agitação marítima na zona doporto da Praia da Vitória, para o período de 2009 a 2010, tendo em conta a variação do nível de maré nesseperíodo. Mais concretamente, define-se o regime de agitação incidente para duas estruturas selecionadas noâmbito deste estudo: o quebramar sul do porto e a defesa frontal da baía. O cálculo dos galgamentos é efetuadocom o modelo neuronal NN_OVERTOPPING2 que, através da introdução dos parâmetros característicos daagitação incidente (altura significativa da onda, período e direção de agitação) e das característicasgeométricas de cada estrutura, permite obter o caudal médio galgado por metro linear de estrutura. A avaliaçãodo risco baseia-se no produto do grau de probabilidade de ocorrência de galgamentos superiores a um dadolimiar pré-estabelecido pelo grau de consequências que advém desse limiar ser ultrapassado. Após a definiçãodos limiares associados a cada estrutura, baseados nas tabelas de Pullen et al. (2007), determina-se afrequência de ocorrência de valores de caudais médios galgados superiores a esses limites e define-se o tipo deconsequências que a excedência desses valores de caudal médio crítico acarreta. Com estes valores, associamsegraus de probabilidade de ocorrência de galgamentos e de consequências, cujo produto permite obter o graude risco associado a cada estrutura.Os resultados assim obtidos nas estruturas selecionadas, quer em termos de alturas de onda significativas,de caudal médio galgado ou de grau de risco associado aos galgamentos, são comparados com os obtidos nasituação em que o nível de maré foi considerado constante e igual a +1.4 m (Z.H.).

No âmbito do projeto de investigação

marítima no litoral setentrional do Rio Grande do Norte, entre os municípios de Macau e Guamaré, durante osperíodos em que se efectuaram três campanhas de medição de ondas e correntes nessa zona: 11 a 12 e 20 a 27de Dezembro/2010 e 15 a 22 de Fevereiro/2011.Assim, partindo dos resultados do modelo de previsão da agitação marítima de larga escala, WAVEWATCHIII, dos dados de vento recolhidos na estação meteorológica de Macau e dos dados de maré da estaçãomarégrafica de Macau para as datas referidas, foram efetuados cálculos com o modelo SWAN em regimeestacionário e compararam-se as simulações com as medições in situ. Os resultados obtidos permitem aferir odesempenho do modelo numérico avaliando as suas potencialidades e limitações, e contribuem para ampliar oconhecimento da hidrodinâmica desta região costeira no Nordeste do Brasil.

Neste artigo é aplicado o método de separação de ondas incidentes e refletidas de Mansard eFunke (1980), para fundo horizontal, considerando duas técnicas de absorção passiva das reflexõesdas ondas implementadas na extremidade do canal oposta ao batedor. Assim, consideraram-se sériestemporais de elevação da superfície livre provenientes de simulações físicas efetuadas no canal deondas irregulares COI3 do LNEC e efetuaram-se ensaios para diversas condições de agitação regularcom períodos de onda de 1.1, 1.5, 2.0 e 2.5 s e alturas de onda de 8 e 10 cm, considerando duastécnicas de absorção passiva, i.e., utilizando tijolos ou tapetes porosos colocados no chão do canal nasimediações da parede oposta ao gerador de ondas. Os coeficientes de reflexão obtidos para estassoluções, usando o referido método, foram comparados com os obtidos considerando uma paredevertical na extremidade do canal.

Nesta comunicação descreveseum procedimento para avaliação das forças exercidas pelaagitação marítima incidente num navio colocado no interior de uma bacia abrigada.O procedimento referido resolve o problema da difracção das ondas com base nos potenciais dasondas radiadas pelos movimentos do navio e no potencial da onda incidente na posição do navioquando ele lá não está. Este último potencial contém toda a informação relativa à propagação dasondas no interior da bacia abrigada. Deste modo e utilizando as relações de Haskind é possívelcalcular as forças de excitação no navio devidas às ondas nele incidentes. Tratasede uma abordagempromissora pois evita a resolução directa do problema de difracção, o que implicaria a discretização datotalidade da fronteira da bacia portuária.Os resultados apresentados nesta comunicação foram obtidos utilizando o potencial da onda incidentefornecido pelo modelo DREAMS, baseado na versão elíptica da equação de declive suave, e opotencial de radiação fornecido pelo modelo WAMIT, que simula o comportamento de corposflutuantes isolados.

A set of procedures to evaluate the time series of the diffraction forces on a moored ship inside a harbor basin ispresented. Nonlinear wave propagation is obtained using a Boussinesq finite element numerical model, BOUSSWMH.Determination of hydrodynamic forces acting on the ship is achieved using a modified version of the WAMITmodel. Finally, time series of the wave forces on the ship and of the inherent motions of the moored ship are obtainedusing BAS numerical model. The main focuses of this work are: the coupling of these three models and themodification of the method used in WAMIT to determine diffraction forces. Some simple and practical applicationsof this procedure are presented as well.

Este trabalho avalia o desempenho de dois modelos do tipo Boussinesq (COULWAVE) e RANS (FLUENT,versão 6.3.26) na zona de rebentação, aferindo as potencialidades e limitações de cada um, quandoaplicados ao caso de teste, estudado experimentalmente no LNEC, de simulação da propagação de ondassobre um fundo de batimetria variável. O modelo COULWAVE é um modelo de diferenças finitas para apropagação de ondas fortemente não-lineares e dispersivas, em zonas de profundidade variável. O modeloFLUENT é um modelo de volumes finitos que utiliza um método de captura de interface VOF paradeterminação da posição da superfície livre.Os resultados numéricos de ambos os modelos são analisados para as várias condições de agitação testadas(ondas monocromáticas com 2 períodos e 2 alturas diferentes). É efectuada uma análise no tempo ecomparados os valores experimentais com os numéricos referentes à altura de onda significativa, e aosvalores mínimo, máximo e médio da velocidade horizontal ao longo do canal (a meio da coluna de água).Determinaram-se parâmetros estatísticos de modo a quantificar a diferença entre os resultados numéricos eexperimentais no caso da altura da onda e da velocidade. É também realizada uma análise espectral demodo a caracterizar o desempenho dos modelos e a sua capacidade na simulação dos efeitos não lineares.Com o modelo FLUENT é ainda apresentada uma comparação entre valores numéricos e experimentais deperfis de velocidade ao longo da coluna de água.

A interacção entre uma onda, em condição de tempestade, e um quebramarde taludes,Zeebrugge na Bélgica, é estudada usando um modelo numérico SPH

A confirmação da eficácia do dimensionamento prévio do manto resistente de um quebra-mar é conseguidaatravés de ensaios em modelo físico reduzido, onde é feita a análise do comportamento hidráulico e/ouestrutural dos seus elementos constituintes.Para avaliar o nível de dano ocorrido ao longo dos ensaios em modelo reduzido, recorre-se por vezes aolevantamento de perfis transversais do perfil ensaiado. De modo a facilitar essa tarefa, tem vindo a testar-serecentemente, no LNEC, a utilização de um método de levantamento da envolvente de taludes de quebra-mares,baseado em estereofotogrametria - técnica de extrair de fotografias, a forma, as dimensões e a posição dosobjetos nelas contidos.

Neste artigo, descreve-se o estudo de ressonância efetuado no Terminal XXI do Porto deSines, com base na análise de dados de campo medidos in situ, durante um conjunto representativo deepisódios considerados ressonantes, e na determinação dos períodos de oscilação própria da baciaportuária, utilizando o modelo numérico DREAMS (Fortes, 1993). Os dados de campo foram obtidospor um marégrafo, do Instituto Hidrográfico, localizado num ponto do interior da bacia portuária, apartir de Março de 2011. Os resultados do modelo são comparados com os dados medidos no interiorda bacia portuária em períodos de ocorrência de fenómenos de ressonância.

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C2IMPRESS is a multi-disciplinary project which aims to enhance understanding and public awareness on multi-hazard risk, based on innovative models, methods, frameworks, tools and technologies to develop decision-making platforms with a fine-grained spatio-temporal data to better assess impacts, vulnerability and resilience on natural hazards. This Report is the Deliverable 1.1 and belongs to Work Package 1, which is mainly addressed to identify the past climate and physical processes that underlie natural disaster events and their consequences

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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