This paper describes a first approach on the risk assessment in port navigation using GUIOMAR, an... more This paper describes a first approach on the risk assessment in port navigation using GUIOMAR, an integrated system for port and coastal engineering modelling developed at the National Civil Engineering Laboratory (LNEC), Portugal, using a GIS software environment. A set of automatic procedures was designed to include a new methodology based on the amplitude of the wave-induced vertical movement of a ship along its trajectory. In this methodology, the risk in port navigation is assessed on the basis of a combination of the probability of exceedance of a pre-set threshold for the ship's vertical movements and its consequences. To test the new procedures, a set of sea wave records obtained at the Sines wave-buoy from 1988 to 2002 was transferred into Sines Port using two numerical models of sea wave propagation and deformation (SWAN and DREAMS), included in the GUIOMAR system. The numerical model WAMIT was used for estimating the wave-induced ship's vertical movements inside the port. By applying the new procedures, automatic generation of risk maps was carried out for navigation in the vicinity of the West breakwater of the Port of Sines. The recent developments contribute towards a more versatile and efficient GUIOMAR system, which results in a more adequate tool to support decision-making processes in port and coastal management.
A 2D numerical investigation of the power absorption of a constrained wave energy hyperbaric conv... more A 2D numerical investigation of the power absorption of a constrained wave energy hyperbaric converter (WEHC) under full-scale sea wave conditions is presented. A fully non-linear numerical model DualSPHysics, based on the coupling of a smoothed particle hydrodynamics (SPH) fluid solver with a multibody dynamics solver, is used to model the interaction between wave and WEHC sub-systems. The numerical model was first validated against experimental data for a similar device, with a good accordance between PTO position and velocity. The model is then employed to study the hydrodynamics of a constrained WEHC considering several sea states, different hydraulic power take-off (PTO) damping and breakwater geometries. It is observed that the capture width ratio (CWR) is particularly sensitive to variations in the PTO damping, although the CWR absolute maximum is less sensitive considering mild variations applied to the PTO damping. Both wave height and wave period have an important effect o...
O presente trabalho descreve a aplicação do sistema integrado para modelação numérica em engenhar... more O presente trabalho descreve a aplicação do sistema integrado para modelação numérica em engenharia portuária e costeira, GUIOMAR, na avaliação do risco para a navegação em zonas portuárias. Trata-se de um sistema desenvolvido no Laboratório Nacional de Engenharia Civil (LNEC) com o software comercial de Informação Geográfica, ArcGIS TM . Naquele sistema foi criado um conjunto de procedimentos automáticos que implementa uma metodologia de avaliação do risco para a navegação, com base na altura do movimento vertical de um ponto de um navio provocado pela agitação incidente no navio ao longo da sua trajectória. Estes novos procedimentos foram testados para dois portos portugueses, o porto de Sines e o porto de praia da Vitória.
The presented work describes a wide range of wave channel tests performed at the National Laborat... more The presented work describes a wide range of wave channel tests performed at the National Laboratory of Civil Engineering (LNEC) with the main objective of introducing an extensive wave analysis regarding mainly the directional spreading analysis of the wave propagation under conditions of wave breaking on complex bathymetries. Therefore, this paper shows the experimental setup, the incident wave conditions, the measurements (free surface elevation and particle velocity) along the wave channel, especially at the wave breaking zone. Based upon the time series of the wave data measurements, a time, spectral and statistical analysis was performed and presented. Analyses are presented relating to: (i) the relative wave height (H/d); (ii) the wave celerity; (iii) the two-dimensional distribution of the particle velocities components; finally (iv) the average wave direction and spreading angle were carried out. The directional spreading analysis was supported by all the other calculated quantities in order to have an effective analysis on the wave breaking phenomena. The work performed contributed for a better understanding of the wave breaking process and especially at the end part of it. Moreover, the data obtained and the results of the performed analysis constitute an important basis for the establishment/improvement of numerical wave breaking models and its validation.
The presented work describes a wide range of wave channel tests performed at the National Laborat... more The presented work describes a wide range of wave channel tests performed at the National Laboratory of Civil Engineering (LNEC), considering different incident wave conditions, with the objective of studying the wave breaking hydrodynamics. Special attention was made to the end of the wave breaking process. The experimental setup, the incident wave conditions, the equipment and the performed measurements (free surface elevation and particle velocity) are herein described. Time, spectral and statistical analysis based upon the measured data are also performed and presented. Moreover, a more deepen analysis related: (i) the relative wave height (H/d); (ii) the wave celerity; (iii) the two-dimensional distribution of the particle velocities components in the xy, xz and yz planes and; (iv) the average wave direction and spreading angle is carried out and presented. Vertical velocity profiles are also presented.
O presente trabalho ilustra uma metodologia desenvolvida no Laboratório Nacional de Engenharia Ci... more O presente trabalho ilustra uma metodologia desenvolvida no Laboratório Nacional de Engenharia Civil (LNEC) com a colaboração do Departamento de Ciências e Engenharia do Ambiente da Universidade Nova de Lisboa para avaliação do risco de inundação de uma zona costeira e a sua aplicação à praia de Vale do Lobo, concelho de Loulé. A metodologia baseia-se em quatro etapas principais: a) divisão da área em estudo em sub-áreas com características semelhantes em termos de defesa costeira; b) determinação da probabilidade de ocorrência de cotas de inundação que excedem limiares pré-estabelecidos para cada área de estudo; c) estabelecimento de factores qualitativos associados às consequências da ocorrência de cotas de inundação que excedem esses limiares; d) combinação dos passos acima para avaliação expedita dos riscos de inundação.
GUIOMAR is an integrated system for coastal engineering modeling, developed with a commercial sof... more GUIOMAR is an integrated system for coastal engineering modeling, developed with a commercial software of Geographical Information Systems (GIS). This system allows the utilization of both wave propagation models and of all the functionalities that are inherent to the GIS software, and it is being designed to help in the decision making process in coastal areas. GUIOMAR system is composed of three main components: a GIS commercial software, a set of modules/models of wave propagation and other pre and post processing algorithms programmed in FORTRAN, and a Graphical User Interface (GUI) developed in VBA for ArcGIS, which is responsible for the communication between the user and the system. At the moment, are available six wave propagation models and a program that automatically generates unstructured grids for the numerical models. In this paper, GUIOMAR structure and a general overview of its interface are presented. In order to achieve important information about the system operab...
This work presents the new developments and the validation of a Smoothed Particle Hydrodynamics (... more This work presents the new developments and the validation of a Smoothed Particle Hydrodynamics (SPH) numerical model used in the National Laboratory of Civil Engineering (Laboratório Nacional de Engenharia Civil - LNEC) for studies in coastal engineering processes. Although the model requires a high CPU time, it proved to be very promising in the simulation of complex flows, such as the wave-structure interaction and the wave breaking phenomenon. For the SPH model validation, physical modeling tests were performed in one LNEC’s flume to study the interaction between an impermeable structure and an incident regular wave. The comparison between numerical and experimental results, i.e. free surface elevation, overtopping volume and pressure, shows the good accuracy of the SPH model to reproduce the various phenomena involving on the wave propagation and interaction with the structure, namely the wave breaking, the wave overtopping and the pressure field on the structure.
ABSTRACT Prediction of wave forces on caisson-type breakwaters is challenging, especially in the ... more ABSTRACT Prediction of wave forces on caisson-type breakwaters is challenging, especially in the case of impact loads that strongly depend on wave reflection, and wave breaking which affects the wave characteristics near the structure. In recent years, numerical models have been further developed and their use is becoming increasingly attractive, such as the Smoothed Particle Hydrodynamics (SPH) numerical models which enable the simulation of complex free surface flows. The SPH numerical model developed at the National Laboratory for Civil Engineering (LNEC) is validated by comparing the numerical results of the wave interaction with a vertical wall using data obtained from physical modeling tests carried out in one of the LNEC׳s flumes. The numerical results presented a good agreement with the physical model tests. The free surface level was well estimated, with a concordance index between numerical results and experimental data of about 90.5–99.1%, presenting an average value of 95.5%. Pressure at the vertical wall shows high intensity and short duration impact loads, and presented a concordance index between numerical results and experimental data about 68.8–94.4%, with an average value about 86.2%. Considering the complex phenomena involved, which is highly difficult to be accurately modeled, numerically and experimentally, a good agreement between physical tests and numerical results was accomplished.
O estuário do rio Douro apresenta-se como uma região muito sensível do ponto de vista ambiental d... more O estuário do rio Douro apresenta-se como uma região muito sensível do ponto de vista ambiental dada a elevada concentração populacional na sua envolvente e a importância das actividades económicas desenvolvidas nesta região. A gestão de um sistema estuarino constitui uma tarefa de elevada dificuldade dada a complexidade dos processos físicos, químicos e biológicos que nele ocorrem. As ferramentas de modelação matemática poderão constituir meios eficientes para a avaliação de alternativas de gestão e para a simulação de situações normais ou excepcionais (cheias e descargas acidentais de poluentes) de funcionamento do estuário. No presente trabalho apresentam-se resultados obtidos na aplicação de modelos hidrodinâmicos e de transporte de massa ao estuário do rio Douro em duas situações distintas: antes e depois da presença das estruturas hidráulicas executadas na sua embocadura. Os modelos foram implementados com o software RMA2, RMA4 e SED2D. O fundo do estuário foi definido usando ...
The main purpose of this work was to develop a mathematical model capable to describe the main ph... more The main purpose of this work was to develop a mathematical model capable to describe the main phytoplankton dynamics at four different oceanic locations of the Portuguese economic exclusive zone. Model implementation was based on data from satellite sensors: wind data (U10), significant wave heights (Hs), forth order spectral momentum of the wave regime (m4), chlorophyll–a (Chl-a), sea surface temperature (SST), cloud fraction; and nutrients data collected through buoy databases (nitrate, phosphate and silica). The developed model considers the main food chain mechanisms associated to the solar irradiation and the nutrients availability at the surface oceanic waters. The model was formulated with a system of mass conservation equations for five state variables: phytoplankton, herbivorous zooplankton, nitrate, phosphates and silicate. The numerical integration of this system of equations allows the performance assessment of the adopted biogeochemical reactions kinetics and to procee...
The knowledge of wave transformation and breaking characteristics near coastline is essential for... more The knowledge of wave transformation and breaking characteristics near coastline is essential for the nearshore hydrodynamics and the design of coastal structures. This paper describes a wide range of wave flume tests performed at the National Laboratory for Civil Engineering (LNEC), located in Lisbon (Portugal), which main objective was to study wave shoaling and breaking over a set of different gentle slopes for several incident waves and thus to contribute for a better understand of the hydrodynamics of wave transformation. The experimental conditions, the measurement equipment, the incident wave characteristics, the type of measurements performed (free surface elevation and particle velocity) and the data obtained are described. Time and spectral analysis based upon the measured data are also performed and presented. For a regular wave with a period of 1.5s and a height of 0.1m are presented and discussed the following results: free surface elevation at selected sections along t...
This paper describes a first approach on the risk assessment in port navigation using GUIOMAR, an... more This paper describes a first approach on the risk assessment in port navigation using GUIOMAR, an integrated system for port and coastal engineering modelling developed at the National Civil Engineering Laboratory (LNEC), Portugal, using a GIS software environment. A set of automatic procedures was designed to include a new methodology based on the amplitude of the wave-induced vertical movement of a ship along its trajectory. In this methodology, the risk in port navigation is assessed on the basis of a combination of the probability of exceedance of a pre-set threshold for the ship's vertical movements and its consequences. To test the new procedures, a set of sea wave records obtained at the Sines wave-buoy from 1988 to 2002 was transferred into Sines Port using two numerical models of sea wave propagation and deformation (SWAN and DREAMS), included in the GUIOMAR system. The numerical model WAMIT was used for estimating the wave-induced ship's vertical movements inside the port. By applying the new procedures, automatic generation of risk maps was carried out for navigation in the vicinity of the West breakwater of the Port of Sines. The recent developments contribute towards a more versatile and efficient GUIOMAR system, which results in a more adequate tool to support decision-making processes in port and coastal management.
A 2D numerical investigation of the power absorption of a constrained wave energy hyperbaric conv... more A 2D numerical investigation of the power absorption of a constrained wave energy hyperbaric converter (WEHC) under full-scale sea wave conditions is presented. A fully non-linear numerical model DualSPHysics, based on the coupling of a smoothed particle hydrodynamics (SPH) fluid solver with a multibody dynamics solver, is used to model the interaction between wave and WEHC sub-systems. The numerical model was first validated against experimental data for a similar device, with a good accordance between PTO position and velocity. The model is then employed to study the hydrodynamics of a constrained WEHC considering several sea states, different hydraulic power take-off (PTO) damping and breakwater geometries. It is observed that the capture width ratio (CWR) is particularly sensitive to variations in the PTO damping, although the CWR absolute maximum is less sensitive considering mild variations applied to the PTO damping. Both wave height and wave period have an important effect o...
O presente trabalho descreve a aplicação do sistema integrado para modelação numérica em engenhar... more O presente trabalho descreve a aplicação do sistema integrado para modelação numérica em engenharia portuária e costeira, GUIOMAR, na avaliação do risco para a navegação em zonas portuárias. Trata-se de um sistema desenvolvido no Laboratório Nacional de Engenharia Civil (LNEC) com o software comercial de Informação Geográfica, ArcGIS TM . Naquele sistema foi criado um conjunto de procedimentos automáticos que implementa uma metodologia de avaliação do risco para a navegação, com base na altura do movimento vertical de um ponto de um navio provocado pela agitação incidente no navio ao longo da sua trajectória. Estes novos procedimentos foram testados para dois portos portugueses, o porto de Sines e o porto de praia da Vitória.
The presented work describes a wide range of wave channel tests performed at the National Laborat... more The presented work describes a wide range of wave channel tests performed at the National Laboratory of Civil Engineering (LNEC) with the main objective of introducing an extensive wave analysis regarding mainly the directional spreading analysis of the wave propagation under conditions of wave breaking on complex bathymetries. Therefore, this paper shows the experimental setup, the incident wave conditions, the measurements (free surface elevation and particle velocity) along the wave channel, especially at the wave breaking zone. Based upon the time series of the wave data measurements, a time, spectral and statistical analysis was performed and presented. Analyses are presented relating to: (i) the relative wave height (H/d); (ii) the wave celerity; (iii) the two-dimensional distribution of the particle velocities components; finally (iv) the average wave direction and spreading angle were carried out. The directional spreading analysis was supported by all the other calculated quantities in order to have an effective analysis on the wave breaking phenomena. The work performed contributed for a better understanding of the wave breaking process and especially at the end part of it. Moreover, the data obtained and the results of the performed analysis constitute an important basis for the establishment/improvement of numerical wave breaking models and its validation.
The presented work describes a wide range of wave channel tests performed at the National Laborat... more The presented work describes a wide range of wave channel tests performed at the National Laboratory of Civil Engineering (LNEC), considering different incident wave conditions, with the objective of studying the wave breaking hydrodynamics. Special attention was made to the end of the wave breaking process. The experimental setup, the incident wave conditions, the equipment and the performed measurements (free surface elevation and particle velocity) are herein described. Time, spectral and statistical analysis based upon the measured data are also performed and presented. Moreover, a more deepen analysis related: (i) the relative wave height (H/d); (ii) the wave celerity; (iii) the two-dimensional distribution of the particle velocities components in the xy, xz and yz planes and; (iv) the average wave direction and spreading angle is carried out and presented. Vertical velocity profiles are also presented.
O presente trabalho ilustra uma metodologia desenvolvida no Laboratório Nacional de Engenharia Ci... more O presente trabalho ilustra uma metodologia desenvolvida no Laboratório Nacional de Engenharia Civil (LNEC) com a colaboração do Departamento de Ciências e Engenharia do Ambiente da Universidade Nova de Lisboa para avaliação do risco de inundação de uma zona costeira e a sua aplicação à praia de Vale do Lobo, concelho de Loulé. A metodologia baseia-se em quatro etapas principais: a) divisão da área em estudo em sub-áreas com características semelhantes em termos de defesa costeira; b) determinação da probabilidade de ocorrência de cotas de inundação que excedem limiares pré-estabelecidos para cada área de estudo; c) estabelecimento de factores qualitativos associados às consequências da ocorrência de cotas de inundação que excedem esses limiares; d) combinação dos passos acima para avaliação expedita dos riscos de inundação.
GUIOMAR is an integrated system for coastal engineering modeling, developed with a commercial sof... more GUIOMAR is an integrated system for coastal engineering modeling, developed with a commercial software of Geographical Information Systems (GIS). This system allows the utilization of both wave propagation models and of all the functionalities that are inherent to the GIS software, and it is being designed to help in the decision making process in coastal areas. GUIOMAR system is composed of three main components: a GIS commercial software, a set of modules/models of wave propagation and other pre and post processing algorithms programmed in FORTRAN, and a Graphical User Interface (GUI) developed in VBA for ArcGIS, which is responsible for the communication between the user and the system. At the moment, are available six wave propagation models and a program that automatically generates unstructured grids for the numerical models. In this paper, GUIOMAR structure and a general overview of its interface are presented. In order to achieve important information about the system operab...
This work presents the new developments and the validation of a Smoothed Particle Hydrodynamics (... more This work presents the new developments and the validation of a Smoothed Particle Hydrodynamics (SPH) numerical model used in the National Laboratory of Civil Engineering (Laboratório Nacional de Engenharia Civil - LNEC) for studies in coastal engineering processes. Although the model requires a high CPU time, it proved to be very promising in the simulation of complex flows, such as the wave-structure interaction and the wave breaking phenomenon. For the SPH model validation, physical modeling tests were performed in one LNEC’s flume to study the interaction between an impermeable structure and an incident regular wave. The comparison between numerical and experimental results, i.e. free surface elevation, overtopping volume and pressure, shows the good accuracy of the SPH model to reproduce the various phenomena involving on the wave propagation and interaction with the structure, namely the wave breaking, the wave overtopping and the pressure field on the structure.
ABSTRACT Prediction of wave forces on caisson-type breakwaters is challenging, especially in the ... more ABSTRACT Prediction of wave forces on caisson-type breakwaters is challenging, especially in the case of impact loads that strongly depend on wave reflection, and wave breaking which affects the wave characteristics near the structure. In recent years, numerical models have been further developed and their use is becoming increasingly attractive, such as the Smoothed Particle Hydrodynamics (SPH) numerical models which enable the simulation of complex free surface flows. The SPH numerical model developed at the National Laboratory for Civil Engineering (LNEC) is validated by comparing the numerical results of the wave interaction with a vertical wall using data obtained from physical modeling tests carried out in one of the LNEC׳s flumes. The numerical results presented a good agreement with the physical model tests. The free surface level was well estimated, with a concordance index between numerical results and experimental data of about 90.5–99.1%, presenting an average value of 95.5%. Pressure at the vertical wall shows high intensity and short duration impact loads, and presented a concordance index between numerical results and experimental data about 68.8–94.4%, with an average value about 86.2%. Considering the complex phenomena involved, which is highly difficult to be accurately modeled, numerically and experimentally, a good agreement between physical tests and numerical results was accomplished.
O estuário do rio Douro apresenta-se como uma região muito sensível do ponto de vista ambiental d... more O estuário do rio Douro apresenta-se como uma região muito sensível do ponto de vista ambiental dada a elevada concentração populacional na sua envolvente e a importância das actividades económicas desenvolvidas nesta região. A gestão de um sistema estuarino constitui uma tarefa de elevada dificuldade dada a complexidade dos processos físicos, químicos e biológicos que nele ocorrem. As ferramentas de modelação matemática poderão constituir meios eficientes para a avaliação de alternativas de gestão e para a simulação de situações normais ou excepcionais (cheias e descargas acidentais de poluentes) de funcionamento do estuário. No presente trabalho apresentam-se resultados obtidos na aplicação de modelos hidrodinâmicos e de transporte de massa ao estuário do rio Douro em duas situações distintas: antes e depois da presença das estruturas hidráulicas executadas na sua embocadura. Os modelos foram implementados com o software RMA2, RMA4 e SED2D. O fundo do estuário foi definido usando ...
The main purpose of this work was to develop a mathematical model capable to describe the main ph... more The main purpose of this work was to develop a mathematical model capable to describe the main phytoplankton dynamics at four different oceanic locations of the Portuguese economic exclusive zone. Model implementation was based on data from satellite sensors: wind data (U10), significant wave heights (Hs), forth order spectral momentum of the wave regime (m4), chlorophyll–a (Chl-a), sea surface temperature (SST), cloud fraction; and nutrients data collected through buoy databases (nitrate, phosphate and silica). The developed model considers the main food chain mechanisms associated to the solar irradiation and the nutrients availability at the surface oceanic waters. The model was formulated with a system of mass conservation equations for five state variables: phytoplankton, herbivorous zooplankton, nitrate, phosphates and silicate. The numerical integration of this system of equations allows the performance assessment of the adopted biogeochemical reactions kinetics and to procee...
The knowledge of wave transformation and breaking characteristics near coastline is essential for... more The knowledge of wave transformation and breaking characteristics near coastline is essential for the nearshore hydrodynamics and the design of coastal structures. This paper describes a wide range of wave flume tests performed at the National Laboratory for Civil Engineering (LNEC), located in Lisbon (Portugal), which main objective was to study wave shoaling and breaking over a set of different gentle slopes for several incident waves and thus to contribute for a better understand of the hydrodynamics of wave transformation. The experimental conditions, the measurement equipment, the incident wave characteristics, the type of measurements performed (free surface elevation and particle velocity) and the data obtained are described. Time and spectral analysis based upon the measured data are also performed and presented. For a regular wave with a period of 1.5s and a height of 0.1m are presented and discussed the following results: free surface elevation at selected sections along t...
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