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Wave overtopping and flood risk assessment in harbours: a case study of the port of Las Nieves, Gran Canaria
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.
Year: 2017
Number Pages:
1-10pp.
Author(s): Santana-Ceballos, J.; Fortes, C. J. E. M.; Reis, M. T. L. G. V.; Rodríguez, G.
: WIT Transactions on the Built Environment
Editor: WIT Press
Volume:
Vol. 170.
Keywords: Port of Las Nieves; Neural networks; Flood risk; Wave overtopping
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Avaliação comparativa de ferramentas neuronais. Aplicação à Praia da Vitória, Terceira, Açores
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).
Year: 2016
Number Pages:
49-68pp.
Author(s): Reis, R.; Fortes, C. J. E. M.; Reis, M. T. L. G. V.; Poseiro, P.; Santos, J. A.
: Vetor
Editor: FURG
Volume:
Volume 26, n. 1.
Keywords: Galgamentos; Risco; Praia da Vitória; Porto; Overtopping predictor V1.1; NN_Overtopping2; Ferramentas neuronais
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Galgamento de uma estrutura portuária protegida por um quebra-mar submerso: o caso do Porto de Leixões, Portugal
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.
Year: 2016
Number Pages:
121-131pp.
Author(s): Bairrão, M.; Neves, M. G.; Reis, M. T.; Taveira-Pinto, F.
: Revista de Gestão Costeira Integrada / Journal of Integrated Coastal Zone Management
Editor: APRH
Volume:
16 (2).
Keywords: Modelação física; IH2VOF; Modelação numérica
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Improving the aerodynamic performance of Vila-Real Bridge deck-section
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
Year: 2016
Number Pages:
72-83pp.
Author(s): Vaz, D.; Almeida , R.A.S.B; Didier, E.; Urgueira, A.P.V.; Borges, A.R.J.
: Journal of Wind Engineering and Industrial Aerodynamics
Editor: Elsevier
Volume:
Volume 156.
Keywords: Box girder; Wind tunnel testing; Sectional model; Oscillations mitigation; Bridge aeroelasticity
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Mechanics of the scouring and sinking of submerged structures in a mobile bed: A physical model study
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.
Year: 2016
Number Pages:
50
Author(s): Khan-Mozahedy, A.B.M.; Muñoz-Perez, J.; Neves, M. G.; Sancho, F. E.; Cavique, R.
: Coastal Engineering
Editor: Elsevier
Volume:
110.
Keywords: Gravel bed; Sandy bed; Pumice stone; Submerged modular structure; Sinking; Scour
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Numerical simulation of flow interaction between stationary and downstream elastically mounted cylinders in tandem at low Reynolds numbers
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.
Year: 2016
Number Pages:
11p.
Author(s): Teixeira, P.; Didier, E.
: Journal of the Brazilian Society of Mechanical Sciences and Engineering
Editor: Springer
Keywords: Wake interference; Tandem arrangement; Circular cylinders; Flow-induced vibration; Finite element method
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Numerical simulation of wave interacting with a submerged cylinder using a 2D RANS model
A 2D RANS numerical model (IH2VOF) is employed to study wave interacting with a circular cylinder with a diameter of 0.02 m in a water depth of 0.27 m, with a wave period of 1.08 s and a wave height of 0.047 m. The influence of the wall proximity on the forces is analyzed for ratiosbetween the pipe (i.e. circular cylinder) distance from the bottom and the pipe diameter varying from 0.04 to 1.5. Results of lift forces and streamlines are compared with the experimental results of Jarno-Druaux et al. (1995) and good agreement is found. Lift, drag and inertia coefficients are also compared with experimental results and the same trend of fundamental quantities with the gap between the cylinder and the bottom was obtained with the model giving slightly larger values. Finally, the influence of the method to estimate the drag and inertia coefficients in the force calculated using Morison equation is analyzed and Morison method shows the better agreement.
Year: 2016
Number Pages:
1
Author(s): Inverno, J.; Neves, M. G.; Didier, E.; Lara, J. L.
: Journal of Hydro-environment Research
Editor: Elsevier
Volume:
12.
Keywords: Hydrodynamic forces; Submerge circular cylinder; Drag and inertia coefficients; RANS modeling
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Performance of a fuzzy ARTMAP artificial neural network in characterizing the wave regime at the Port of Sines (Portugal)
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
Year: 2016
Number Pages:
1362
Author(s): Santos, F.; Reis, M. T. L. G. V.; Fortes, C. J. E. M.; Lotufo, A.; Neves, D. R.; Poseiro, P.; Maciel, G.
: Journal of Coastal Research
Editor: Coastal Education and Research Foundation
Volume:
Volume 32, Issue 6.
Keywords: Artificial neural network (ANN) training and validation; In situ measurements; Wave buoy data; Numerical wave propagation modeling
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Photogrammetric analysis of rubble mound breakwaters scale model tests
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.
Year: 2016
Number Pages:
541
Author(s): Lemos, R.; Loja, M.A.R.; Rodrigues, J.; Rodrigues, J.A.S.
: AIMS Environmental Science
Editor: AIMS Press
Volume:
3(3).
Keywords: Scale model tests; Pphotogrammetric analysis; Rubble-mound breakwaters
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Smoothed particle hydrodynamics numerical model for modelling an oscillating water chamber
This paper presents theapplicatio nand thevalidation of the SPH numerical model SPHyCE, based on astandard Smoothed Particle Hydrodynamics formulation, for modeling anonshore oscillating waterchamber, comparing results of amplification factor and phase lag with those obtained by a mesh-basedRANS model .Firstly, ananalysis of the results for differentre solutions (i.e.particle dimension) showedthe independence of results with refinement. Secondly, the amplification factor of mean free surfaceelevation inside th eoscillating water chamber and the phase lag between time series of free surfaceelevation outside and inside the water chamber were analysed. A good agreement was achieved between the mesh free SPHyCE model and the mesh-based RANS model. SPHyCE model was finally applied to analyse the hydrodynamic fluid flow inside and outside the water chamber and to quantify the forces onthe vertical wall and the amplification factor for different incident wave heights for a rough sea state with complex wave breaking, impact loads and overtopping, contributing to the future applications ofSPH models for development and studies of OWC devices.
Year: 2016
Number Pages:
397
Author(s): Didier, E.; Neves, D. R.; Teixeira, P.; Dias, J.; Neves, M. G.
: Ocean Engineering
Editor: Elsevier
Volume:
123.
Keywords: Coastal engineering; Hydrodynamic forces; Wave
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A nonlinear finite element method for wave propagation over gently varying depths
N/A
Year: 2000
Author(s): Fortes, C. J. E. M.; Fernandes, J. L. M.
Editor: ******
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Diagnóstico de Obras de Protecção Portuária
N/A
Year: 2000
Number Pages:
50 p.
Author(s): Neves, M. G.; Santos, J. A.; Ferreira, Ó
Editor: ******
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Fenómenos de turbulência e correntes geradas pela rebentação de ondas
N/A
Year: 2000
Number Pages:
18 p.
Author(s): Sancho, F. E.; Neves, M. G.; Tomasicchio, G.; Archetti, R.
Editor: ******
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Modelação Numérica da Evolução de Praias Estuarinas - Programa PDCTM (FCT)
N/A
Year: 2000
Author(s): Freire, P.; Oliveira, F. S. B. F.; Fortes, C. J. E. M.
Editor: ******
Morfodinâmica de Embocaduras Estuarinas: Análise a médio e longo prazo
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Quebra-mares perfurados: da caracterização do processo de interacção ondas-estrutura ao desenvolvimento de modelos de dimensionamento
N/A
Year: 2000
Number Pages:
50 p.
Author(s): Sarmento, A.; Neves, M. G.; Pita, C.; Oliveira, I. M.; Pontes, T.
Editor: ******
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BRISA: Breaking waves interaction with sandbars
N/A
Year: 1999
Number Pages:
30 p.
Author(s): Sancho, F. E.
Editor: ******
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Funcionalidade e estabilidade de estruturas de abrigo à acção de agitação marítima
N/A
Year: 1999
Number Pages:
16 p.
Author(s): Neves, M. G.; Losada, M. A.
Editor: ******
Morfodinâmica de Embocaduras Estuarinas: Análise a médio e longo prazo
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PRIMO: Prediction and impacts of runup and overwashes
N/A
Year: 1999
Number Pages:
33 p.
Author(s): Ferreira, Ó; Sancho, F. E.
Editor: ******
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