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Simulation of wave action on a moored container carrier inside Sines’ Harbour
No full textThe integrated numerical tool SWAMS (Simulation of Wave Action on Moored Ships) is used to simulate the behavior of a moored container carrier inside Sines’ Harbour. Wave, wind, currents, floating ship and moorings interaction is discussed. Several case scenarios are compared differing in the layout of the harbour and wind and wave conditions. The several harbour layouts correspond to proposed alternatives for the future expansion of Sines’ terminal XXI that include the extension of the East breakwater and of the quay. Additionally, the influence of wind on the behavior of the ship moored and the introduction of pre tensioning the mooring lines was analyzed. Hydrodynamic forces acting on the ship are determined using a modified version of the WAMIT model. This modified model utilizes the Haskind relations and the non-linear wave field inside the harbour obtained with finite element numerical model, BOUSS-WMH (Boussinesq Wave Model for Harbors) to get the wave forces on the ship. The time series of the moored ship motions and forces on moorings are obtained using BAS solver.1113-1121ppDHA/NP
An interactive WebGIS observatory platform for enhanced support of integrated coastal management
No full textA new WebGIS observatory platform is presented, tailored for risk assessment and emergency preparation and response
in coastal areas. The tool combines a sophisticated forecast modeling system for multi-scale analysis of water bodies,
including waves, hydrodynamics and oil spills prediction, with real-time monitoring networks for forcing and
continuous validation purposes. Tailor-made visualization and analysis products, conceptualized for multiple uses
through a service-oriented framework, provide an easy and interactive access to both data and predictions. The system
was customized for oil spills risk assessment and the rapid response to an oil spill emergency, and applied to the Aveiro
lagoon. The tool addresses oil spill problems in two complementary ways: 1) a detailed risk assessment through
georeferenced hazard and vulnerability maps and GIS layers of information to support the definition of contingency
plans; and 2) the visualization of georeferenced oil spill predictions produced by a real-time oil spill forecasting system.
Improvements relative to existing risk systems are 1) the possibility of selecting quick-access predictions for fast
emergency response or high-quality, georeferenced GIS prediction products, 2) the flexibility in accessing products to
evaluate local impacts of oil spills both in the water column and in the intertidal areas, and 3) the enhanced hazard and
risk analysis through a combination of a multi-scenarios approach with the historical database of spill predictions,
forced by daily hydrodynamic forecasts. Dependability of information, for both model results and monitoring data, is
being implemented through innovative ways, targeting the robustness and quality control of the WebGIS platform.7507 - 512Vol. 70DHA/GTIJournal of Coastal Researc
Characterisation and numerical modelling of the geometry of rock joints
No full textThis paper describes the measurement and analysis of the roughness of natural rock joints with the
aim of proceeding to their characterisation and comparison. Eight rock joints (corresponding to
sixteen surfaces) were scanned with a three-dimensional scanner. This was followed by the
description and characterisation of the surface roughness, as well as its reproduction and generation
using techniques such as fractal models and Fourier transforms. Shear tests under constant normal
load were performed, the joint surfaces were again scanned, and the resulting roughness surfaces were
compared allowing the evaluation of asperity breakage and surface wear. One of the joint specimens
was tested under several normal stresses, which allowed the estimation of its mechanical
characteristics, and was scanned after each test to evaluate the influence of the normal and shear load
on the variation of roughness.
The scans of the rock joints produced accurate numerical descriptions of their topologies, allowing
countless possibilities of future studies, such as the study of the matching of rock joints by the
numerical adjustment of bottom and top surfaces, the statistical and geostatistical characterisation of
rock joints or the degradation of roughness after normal and shear tests. This paper presents an
overview of the research work that is still under way.10pDT/NI
Construction of decision rules for early detection of a developing concrete arch dam failure scenario. A discriminant approach
No full textTo improve the effectiveness of concrete dam safety control in real time, a method is presented for the
construction of decision rules for the early detection of developing failure scenarios. The decision rules
are based on the use of linear discriminant models developed with data obtained through mathematical
models of the dam’s behaviour. The aim is to combine the physical quantities measured by the automated
monitoring system of the dam, appropriately weighted, into a new single index allowing the classification
of the observations into one of two classes (normal behaviour and development of a failure scenario).959142DBB/NOComputers and Structure
Simulação numérica do comportamento de um navio amarrado no Terminal XXI do Porto de Sines
No full textEste trabalho apresenta a aplicação da ferramenta numérica SWAMS para caracterizar o comportamento de um navio amarrado na bacia do Terminal de Contentores do Porto de Sines. São analisados os movimentos do navio, as forças nas amarras e nas defensas. Analisa-se ainda a influência do vento e da introdução de pré tensionamento nas amarras assim como a resposta do sistema quando sujeito a ondas longas. Os resultados permitem avaliar qual destes fatores tem maior influência sobre os movimentos do navio e a sua segurança.349-357pp.DHA/NP
Modelagem numérica e física de um quebra-mar poroso
No full textOs modelos Lagrangianos de tipo Smoothed Particle Hydrodynamics (SPH) apresentam-se como uma alternativa interessante para modelar a interação entre ondas e estruturas costeiras e marítimas. Estes modelos permitem representar corretamente a física dos fenômenos. No entanto, como qualquer modelo numérico, a precisão dos resultados depende fortemente da resolução, i.e. da dimensão das partículas. O estudo de análise da convergência com a resolução, para a elevação da superfície livre e o galgamento, mostra assim que a convergência é obtida para resoluções diferentes em função do tipo de fenômeno analisado e para resoluções mais finas quando a não-linearidade dos fenômenos aumenta. Os resultados numéricos foram comparados com os dados experimentais obtidos em canal de ondas evidenciando a convergência quer da elevação de superfície livre quer do galgamento com a resolução.8pDHA/NP
Comparison between time, spectral and wavelet analysis on wave breaking and propagation
No full textThe present work focuses on the comparison between three types of data analysis (time
analysis; Fourier transform spectral analysis; and wavelet transform spectral analysis) applied
to different types of waves (monochromatic, bichromatic and irregular). The main objective is
to study experimentally wave shoaling and breaking over a set of different gentle slopes for
several incident waves.
The data and results from time, Fourier and wavelet analysis presented include: free surface
elevation along the flume and the corresponding amplitude spectra; significant wave height,
Hs, and significant wave period, Ts, along the flume.11010pDHA/NPE201414 a 16 de abri
Influência das correntes no comportamento do modelo SWAN na zona de Diogo Lopes, Brasil
No full textA zona de Diogo Lopes, situada no estado do Rio Grande do Norte, Brasil, foi alvo de
vários estudos interdisciplinares, que incluíram a caracterização da agitação marítima ao longo
desta costa (Ângelo et al. 2012, Matos et al. 2013). Esta é dominada por um regime de alternância
de brisa marítima e terrestre que colocou certas dificuldades. Para obviar a estas, recorre-se,
novamente, ao modelo SWAN para a simulação do estado de mar, mas com um domínio de
cálculo alargado, um campo de ventos, obtido na estação meteorológica de Macau, diferente e
com a introdução da interacção das ondas e correntes. Estas são provenientes do modelo
hidrodinâmico SISBAHIA desenvolvido na referida Universidade. O forçamento ao largo é obtido
recorrendo ao modelo Wavewatch III. Para a verificação das simulações, utilizaram-se medições
de sensores AWAC para o período de 11 a 12 de Dezembro de 2010, em dois pontos distintos da
malha computacional.62199-202ppDHA/NPE201424 a 26 de junh
Relatório do Trabalho Realizado pelo Bolseiro Rui Reis (Setembro 2012 – Março 2014)
No full textEste registo pertence ao Repositório Científico do LNEC007pDHA/NP
Opções de compartimentação na habitação
No full textTrata-se da possibilidade de juntar e dividir compartimentos e espaços, da escolha entre ter mais compartimentos mais pequenos ou menos compartimentos maiores e, finalmente, da separação entre zonas mais sociais ou mais íntimas.1 fig3 pInfohabitar, Ano X, n.º 495DED/NUTRevista Infohabita