Papers
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Energy rate balance applied to coastal engineering problems by using RANS-VoF models in numerical wave flumes 
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.
Year: 2025
Author(s): Teixeira, P.; Didier, E.
: Ocean Engineering
Editor: Elsevier
Keywords: Rubble-mound breakwater; Oscillating water column wave energy converter; Energy rate balance; Coastal engineering; Numerical wave flume; RANS models
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An assessment of 3D scanning methods in physical models
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.
Year: 2024
Author(s): Capitão, R.; Lemos, R.; Fortes, C. J. E. M.; Jónatas, R.
Editor: COSE
Keywords: 3D scans; Reconstruction Techniques; Damage Progression; Breakwater; Physical Modelling
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Analytical and numerical modelling of wave dissipation over rigid and flexible vegetation in a flume: Drag coefficient calibration
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.
Year: 2024
Author(s): Reis, R.; Fortes, C. J. E. M.; Suzuki , T.
Editor: IARH EUROPE CONGRESS
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Deep Neural Network Enhanced Early Warning System for Ports Operations
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
Year: 2024
Author(s): Pinheiro, L.; Fortes, C. J. E. M.; Gomes, A.
Editor: IARH EUROPE CONGRESS
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Development of a Bayesian network-based early warning system for storm-driven coastal erosion
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 to develop, test, and implement an operational coastal erosion early warning system supported by a particular method of machine learning. Thus, the system combines Bayesian Networks, and state-of-the-art numerical models, such as XBeach and SWAN, to predict storm erosion impacts in urbanized areas. This system was developed in two phases. In the development phase, all information required to apply the machine learning method was generated including the definition of hundreds of oceanic synthetic storms, modeling of the erosion caused by these storms, and characterization of the impact levels according to a newly defined eerosion iimpact index. This adimensional index relates the distance from the edge of the dune/beach scarp to buildings and the height of that scarp. Finally, a Bayesian Network that acted as a surrogate of the previously generated information was built. After the training of the network, the conditional probability tables were created. These tables constituted 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 latest considered as the benchmark, and (2) by assessing the predictive skills of the Bayesian Network through the unbiased iterative k-fold cross-validation procedure. Regarding the first comparison, the analysis considered the entire duration of three large storms whose return periods were 10, 16, and 25 years, and it was observed that the Bayesian 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 conditions disappeared after predicting potential consequences. Regarding the Regarding the second validation approach, second validation approach, the k-fold cross-validation procedure was applied to the peak of a set of varying storms and it demonstrated that the predictive skills were maximized (63%
Year: 2024
Number Pages:
1-15pp.
Author(s): Garzon, J.L.; Ferreira, Ó.; PLOMARITIS, T.A.; Zózimo, A. C.; Fortes, C. J. E. M.; Pinheiro, L.
: Coastal Engineering
Editor: Elsevier
Volume:
Vol 189 (104460).
Keywords: HIDRALERTA; Sandy beaches; Bayesian networks; Numerical modeling; Prediction system
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Development of a Bayesian network-based early warning system for storm-driven coastal erosion
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%
Year: 2024
Author(s): Garzon, J.L.; Ferreira, O.; PLOMARITIS, T.A.; Zózimo, A. C.; Fortes, C. J. E. M.; Pinheiro, L.
: Coastal Engineering
Editor: Elsevier
Volume:
189 (2024) 104460.
Keywords: HIDRALERTA; Sandy beaches; Bayesian networks; Numerical modeling; Prediction system
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Experimental investigation of wave severity and mooring pretension on the operability of a moored tanker in a port terminal
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
Year: 2024
Author(s): Abdelwahab, H.S.; Pinheiro, L.; Santos, J. A.; Fortes, C. J. E. M.; Guedes Soares, C.
: Ocean Engineering
Editor: Elsevier
Volume:
291 (2024) 116243.
Keywords: Mooring pretension; Moored ship; Ship motions; Port downtime; Ship operability; Physical modelling
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Experimental study of an onshore dual chamber oscillating water column device
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.
Year: 2024
Number Pages:
16p..
Author(s): Gadelho, J.; REZANEJAD, K.; Guedes Soares, C.; Santos, J. A.; Anastas, G.; Fortes, C. J. E. M.
: Ocean Engineering
Editor: Elsevier
Volume:
Volume 300 (117240).
Keywords: Reflection coefficients; Efficiency improvement; Breakwater; Experiments; Oscillating water column
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Experimental study on drag coefficient of flexible vegetation under non-breaking waves
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%.
Year: 2024
Number Pages:
14p..
Author(s): Reis, R.; Fortes, C. J. E. M.; Rodrigues, J.; HU, Z.; Suzuki , T.
: Ocean Engineering
Editor: Elsevier
Volume:
Volume 296.
Keywords: Wave dissipation; Inertia; Vegetation motion; Flexible vegetation; Drag coefficient
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Exploring Wave
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
Year: 2024
Author(s): El Rahi, J.; Martinez-Estevez, I.; Reis, R.; Tagliafierro, B.; Dominguez, J.M.; Crespo, A.J.C.; Stratigaki, V.; Suzuki, T.; Troch, P.
Editor: MDPI
Keywords: Project chrono; DualSPHysics; SPH-FEA coupling; Fluid
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Comunicação
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Metodologia de propagação de regimes de agitação marítima do largo para a costa: análise dos modelos BACKTRACK-REFSPEC e SWAN
N/A
Year: 2002
Number Pages:
17 p.
Author(s): Coli, A. B.; Santos, J. A.; Fortes, C. J. E. M.; Capitão, R.; Carvalho, M. M.
Editor: ******
Info
Agitação marítima no interior do porto de Vila do Conde.
N/A
Year: 2001
Number Pages:
21 p.
Author(s): Zózimo, A. C.; Capitão, R.; Neves, M. G.; Fortes, C. J. E. M.; Carvalho, M. M.
Editor: ******
Info
Controle por Piloto Automático do Modelo Numérico do Lnec para Comportamento de Navios em Manobra
N/A
Year: 2001
Number Pages:
17 p.
Author(s): Santos, J. A.; Marcos Rita, M.
Editor: ******
Info
Doca de recreio do porto de Vila do Conde - Estudos de agitação marítima
N/A
Year: 2001
Number Pages:
19 p.
Author(s): Zózimo, A. C.; Capitão, R.; Neves, M. G.; Fortes, C. J. E. M.; Carvalho, M. M.
Editor: ******
Info
Estabilidade e galgamento de quebra mares de taludes. Influência do modo e densidade de colocação de blocos cúbicos
N/A
Year: 2001
Number Pages:
13 p.
Author(s): Neves, M. G.; Silva, L. G.; Reiter, S.
Editor: ******
Info
Estudos de agitação e ressonância em modelo matemático
N/A
Year: 2001
Number Pages:
34 p.
Author(s): Fortes, C. J. E. M.; Covas, J. A.
Editor: ******
Info
Ferramentas de inspecção e diagnóstico de obras de protecção portuária
N/A
Year: 2001
Number Pages:
7 p.
Author(s): Santos, J. A.; Silva, L. G.; Neves, M. G.; Silvestre, C.; Oliveira, P.; Pascoal, A.
Editor: ******
Info
Modelo de propagação e deformação de ondas irregulares em zonas portuárias
N/A
Year: 2001
Number Pages:
18 p.
Author(s): Zózimo, A. C.; Fortes, C. J. E. M.; Neves, M. G.; Fernandes, J. L. M.
Editor: ******
Info
Observação Sistemática de Obras Marítimas. Súmula da actividade desenvolvida pelo LNEC
N/A
Year: 2001
Author(s): Silva, L. G.; Santos, J. A.; Neves, M. G.; Damião, A. D.
Editor: ******
Info
Pacote de software geral para tratamento e geração de agitação marítima de curto prazo. Aplicação à geração em canal de ondas irregulares de perfis de agitação pré-estabelecidos
N/A
Year: 2001
Number Pages:
20 p.
Author(s): Capitão, R.; Carvalho, M. M.
Editor: ******
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Hydraulics and Environment Department
