Publications

Numerical modeling of the interaction between waves and coastal structures is a challenge due to the many nonlinearphenomena involved, such as wave propagation, wave transformation with water depth, interaction between incident andreflected waves, runup/rundown and wave overtopping. For simulating such complex free-surface flows, numerical modelsbased on Lagrangian formulation, such as Smoothed Particle Hydrodynamics (SPH), are on option. Even though validationof these numerical models is essential, comparing numerical results with experimental data is not an easy task. In thepresent paper, an SPH numerical model is validated comparing numerical results of waves interacting with a compositebreakwater with data obtained from physical model tests carried out in one of the LNEC

Groins are cross shore structures built to promote shoreline stabilization. However, the specific impact of these structures on the wave conditions and velocity field nearshore (and hence, on sediment transport) is still poorly understood. Therefore, this study wishes to extend this knowledge using a numerical model, COULWAVE, previously validated with field data. For that, a typical bar-trough profile is considered and different groin lengths and orientations are tested, under the influence of different significant incident-wave heights and sea-surface levels.The hydrodynamics factors are found to have a greater impact on the nearshore wave conditions than the groin geometry. The variation of significant incident-wave height imparts the greater changes in wave height nearshore, where the groin would be located. The typical tidal range is also important, since a 2 m change in sea surface level can cause great depth changes over bathymetric features and thus influence wave propagation. Although less important, the geometry of the groin should also be considered. The greater the length, the greater the sheltering effect expected, extending further to the lee-side of the groin. The impact will also reach a broader region. With a smaller impact verified, the best orientation of the groin is hard to unravel.

The study of ways of converting ocean wave energy into a useful one and the improvement of theexisting equipment are complex engineering problems and very important issues in today

The length of the Portuguese coast, the severity of the sea conditions and the concentration of population and economic activities on its coastal zone justify the importance of studying wave-induced risks and, in particular, flooding due to wave action. Indeed, emergency situations caused by adverse sea conditions are frequent and put in danger the safety of people and goods, with negative impacts for society, economy and natural heritage. So, assessing the risk of flooding of coastal and port areas is essential for the proper planning and management of these areas. In this framework, a methodology for the flood risk assessment in coastal and port areas is under development. The methodology is embedded into the HIDRALERTA system, a novel integrated system for port and coastal management, designed to prevent emergency situations, to support their management and to forecast incidental long-term interventions. The present paper describes the methodology, the HIDRALERTA system and a case study, the São João da Caparica beach, on the Lisbon

Para reducir la agitación en el interior del puerto de Vila do Porto, Azores, se ha proyectado una modificación del muelle interior de atraque de los ferries, con el objetivo de aminorar la reflexión y disminuir el rebase, sin que con eso se reduzca demasiado el área útil de la dársena portuaria. La solución propuesta es una plataforma de forma triangular en planta apoyada en pilares rectangulares, bajo la cual se ha colocado un talud de escollera para disminuir la reflexión. Se presentan los resultados de ensayos en modelo físico 3D y los obtenidos con dos modelos numéricos RANS en lo que se refiere a presiones en la plataforma y reducción de la reflexión (el modelo IH-2VOF y el FLUENT).

Submarine outfalls need to be evaluated as part of an integrated environmental protection system forcoastal areas. Although outfalls are tight with the diversity of economic activities along a denselypopulated coastline being effluent treatment and effluent reuse a sign of economic prosperity, precautionsmust be taken in the construction of these structures. They must be designed so as to have the leastpossible impact on the environment and at the same time be economically viable. This paper outlines theinitial phases of a risk assessment procedure for submarine outfall projects. This approach includesa cost-benefit analysis in which risks are systematically minimized or eliminated. The methods used inthis study also allow for randomness and uncertainty. The input for the analysis is a wide range ofinformation and data concerning the failure probability of outfalls and the consequences of an operationalstoppage or failure.As part of this risk assessment, target design levels of reliability, functionality, and operationality weredefined for the outfalls. These levels were based on an inventory of risks associated with suchconstruction projects, and thus afforded the possibility of identifying possible failure modes. Thisassessment procedure was then applied to four case studies in Portugal. The results obtained were thevalues concerning the useful life of the outfalls at the four sites and their joint probability of failureagainst the principal failure modes assigned to ultimate and serviceability limit states. Also defined werethe minimum operationality of these outfalls, the average number of admissible technical breakdowns,and the maximum allowed duration of a stoppage mode. It was found that these values were inconsonance with the nature of the effluent (tourist-related, industrial, or mixed) as well as its importancefor the local economy. Even more important, this risk assessment procedure was able to measure theimpact of the outfalls on human health and the environment.

Neste artigo descreve-se a ferramenta numérica SWAMS que se baseia nos modelosnuméricos DREAMS, BOUSS-WMH e MOORNAV para caracterizar a resposta dum navioamarrado no interior dum porto sujeito à acção da agitação marítima. Os dois primeirosmodelos simulam a propagação de ondas lineares e não lineares em zonas abrigadas deprofundidade variável, tendo em conta os fenómenos da refracção, difracção, reflexãoparcial, dissipação de energia devida ao atrito de fundo e rebentação das ondas. Enquantoo modelo DREAMS é um modelo linear baseado na equação de declive suave, o modelonão linear BOUSS-WMH é baseado nas equações de Boussinesq. O comportamento donavio amarrado é simulado com o pacote numérico MOORNAV que engloba um modelonumérico para resolver, no domínio da frequência, os problemas de radiação e de difraçãoda interacção de corpos flutuantes com ondas e um modelo que converte os resultadosdaqueles problemas do domínio do tempo para o domínio da frequência e que monta eresolve as equações do movimento do navio amarrado, BAS.Apresentam-se asmodificações introduzidas no modelo WAMIT para calcular as forças de difracção com basenas relações apresentadas em Haskind. Tais relações, porque utilizam o potencial develocidades obtido com o modelo DREAMS ou com o modelo BOUSS-WMH, permitemlevar em conta a refracção, difracção ou reflexão que podem ocorrer na propagação dasondas para o interior de uma bacia abrigada. Para além da descrição dos modelosnuméricos na ferramenta SWAMS, apresenta-se a forma como os resultados sãotransferidos entre eles bem como aplicações da mesma para ilustrar as suas capacidades.

The current study proposes prediction formulas both for random wave runup and mean overtopping discharge at seawalls constructedon land or in very shallow water. Although several existing formulas for runup and overtopping use the incident wave characteristicsat the toes of seawalls, this study adopts the equivalent deepwater wave characteristics and an imaginary seawall slope for easy application of theformulas, especially in relation to seawalls constructed on land. The prediction formulas for overtopping use the predicted runup values. For thewave runup prediction formulas two sets of experimental data are used; i.e., a new set of data and the data obtained in a previous study. For thewave overtopping prediction formulas, the experimental data measured in a previous study are used. Comparisons with measurements showgood performances of both new prediction methods.

This paper presents the new boundary condition implemented in the LNEC SPH numerical model based on theSPHysics model and on a standard Smoothed Particle Hydrodynamic formulation: the piston-type wave maker includesnow dynamic wave absorption and allows simulating a semi-infinite flume. Verification of the active wave makerabsorption is carried out through the simulation of the interaction between a regular incident wave and an impermeablevertical breakwater. Results show that the active wave-maker allows outgoing waves to be absorbed and reflection at thewave-maker to be avoided

Este artigo aborda a análise comparativa entre as medições de agitação marítima efectuadas na Praia da Cornélia (Costa da Caparica, Portugal), durante os dias 12 a 14 de Maio de 2010, e os resultados numéricos da aplicação do modelo não-linear do tipo Boussinesq, COULWAVE. Esta análise tem como principal objectivo a avaliação do desempenho deste modelo numérico na simulação da propagação de ondas em condições reais, pretendendo evidenciar, deste modo, as suas potencialidades e limitações.As condições de fronteira do modelo foram geradas com base em séries temporais de elevação medidas a uma profundidade aproximada de 7.6 m (relativa ao zero hidrográfico

O objetivo do presente trabalho foi avaliar o desempenho da metodologia de análise de vídeo Timestack na estimativa do espraiamento e na identificação de eventos de galgamento em modelos físicos de quebra-mares de talude com manto resistente composto por cubos Antifer.No primeiro caso, foi avaliado o espraiamento num modelo físico tridimensional do quebra-mar de taludes, para condições de agitação com incidência frontal e oblíqua relativamente ao talude. No segundo caso, identificaram-se os eventos de galgamento considerando ensaios realizados num modelo físico bidimensional do quebra-mar de taludes. Todos os casos de teste realizados mostraram resultados muito satisfatórios, evidenciando a versatilidade da técnica.

Marginal protection structures or adherent longitudinal defenses, whose main function is to mitigate overtopping, are structures parallel to the coast. They are intended to serve as protection and shelter against flooding, due to overtopping, dissipating wave energy in their interaction with the structure, and in areas strongly affected by coastal erosion, minimizing the risk of damage to roads, walkways or buildings in the proximity.The evaluation of run-up and overtopping in marginal protection structures is determined according to the conditions of incident sea agitation and the characteristics of the structure, being fundamental for the design of new structures and in the verification of the safety of existing structures.

O SAFEPORT é um sistema de previsão e alerta de perigos associados a navegação dentro do Porto de Sines. Este documento apresenta uma aplicação deste sistema, mais especificamente, descreve a modelação numérica que permitiu simular o comportamento de três navios amarrados em três terminais do Porto de Sines, sob as condições de agitção marítima causadas pela tempestade Dora. Os alertas emitidos aos movimentos dos navios e às forças exercidas nos seus cabos de amarração permitiram concluir que o sistema SAFEPORT é capaz de prever e emitir alertas em situações potencialmente perigosas.

Damage progression in wave-exposed physical models of rubble-mound breakwaters can be assessed using two methods: traditional quantification of armor element movements or newer approaches involving non-intrusive surveys, utilizing photogrammetry, RGB sensors, Time of Flight depth sensors, and LiDAR laser scanning sensors to determine eroded volumes and depths between consecutive armor layer surveys. These techniques allow for the creation of three-dimensional surface models with varying accuracy, depending on survey conditions and post-processing methodologies. The performance, suitability, and usability of these techniques in assessing damage progression are comparatively evaluated. Furthermore, the advantages and disadvantages of each technique are identified, and a sensitivity analysis is presented for each one.

No âmbito do projeto das obras de expansão e requali

A avaliação da evolução dos danos causados pela agitação incidente em modelos físicos de quebra-mares de taludes pode ser efetuada através da quantificação de movimentos e quedas dos elementos do manto resistente (métodos tradicionais), ou pela determinação de volumes e profundidades erodidas entre levantamentos consecutivos dos respetivos taludes (métodos mais atuais). Para se efetuarem esses levantamentos dos taludes, podem aplicar-se técnicas fotogramétricas com sensores RGB, sensores de profundidade baseados na metodologia ToF (Time of Flight) e sensores de laser LiDAR (Light Detection And Ranging).No presente trabalho, aplicam-se essas técnicas ao modelo físico do quebra-mar do porto da Ericeira, que está presentemente a ser ensaiado no LNEC, e avalia-se, comparativamente, o respetivo desempenho, adequabilidade e usabilidade na determinação da evolução dos danos, identificando vantagens e desvantagens de cada uma destas técnicas.

A praia da Vagueira está localizada no Município de Vagos, distrito de Aveiro e é protegida por uma estrutura de defesa frontal aderente que foi requali

O projeto

A avaliação do dano causado pela agitação incidente em modelos físicos de quebra mares de taludes pode ser realizada comparando volumes e profundidades erodidas entre levantamentos consecutivos de cada talude. Atualmente, estes levantamentos podem ser realizados de forma não intrusiva, recorrendo a técnicas fotogramétricas, a laser scan ou a sensores de posição baseados na metolodologia Time of Flight (ToF). Dependendo das condições de levantamento e da metodologia de pós-processamento das nuvens de pontos obtidas, estas técnicas permitem obter modelos tridimensionais de superfície, com elevada precisão.

This paper presents the prototype of HIDRALERTA for the port of Aveiro, showing the potential of the system, both as a tool for forecasting and warning of emergency situations and as a tool for planning and managing the risk in climate change scenarios. The prototype for Aveiro harbour showcases a new feature of HIDRALERTA system, which is the early warning system for maneuvering ships along the entrance channel, following the work of the BlueSafePort project.

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