Diogo Neves | National Laboratory for Civil Engineering (original) (raw)

Papers by Diogo Neves

Research paper thumbnail of Managing wave-induced risks in port operations

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Research paper thumbnail of Application to the Port of Sines of a new tool for risk assessment in port navigation

Journal of Coastal Conservation, 2012

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Research paper thumbnail of Numerical Model of Constrained Wave Energy Hyperbaric Converter under Full-Scale Sea Wave Conditions

Journal of Marine Science and Engineering

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...

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Research paper thumbnail of Wave propagation in a wave channel, physical modelling

Thermal Engineering

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Research paper thumbnail of Avaliação do risco para a navegação em dois

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Research paper thumbnail of Directional spreading model in a wave channel: Wave propagation and wave breaking

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Research paper thumbnail of Physical modelling of wave propagation and wave breaking in a wave channel

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.

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Research paper thumbnail of A Comparison of Wave Breaking with RANS and SPH numerical models

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Research paper thumbnail of Avaliação do Risco de Inundação na Praia de Vale do Lobo

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.

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Research paper thumbnail of GUIOMAR: Geo(graphical) User Interface for cOastal and MARine Modeling. Wave regime at Sines

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...

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Research paper thumbnail of Modelling of Hydrodynamics Around an Impermeable Breakwater: Comparison Between Physical and SPH Numerical Modeling

Revista de Engenharia Térmica

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.

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Research paper thumbnail of Wave interaction with a vertical wall: SPH numerical and experimental modeling

Ocean Engineering, 2014

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.

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Research paper thumbnail of Hidrodinâmica da zona oceânica adjacente à Península Ibérica

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Research paper thumbnail of Modelação matemática da hidrodinâmica e da intrusão salina no estuário do rio Douro

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Research paper thumbnail of Probabilistic assessment of the safety of sea defences using level II and level III methods

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Research paper thumbnail of Efeito Das Obras Da Embocadura Na Hidrodinâmica, Intrusão Salina e Dinâmica Sedimentar Do Estuário Do Rio Douro

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 ...

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Research paper thumbnail of Avaliação comparativa do risco de galgamentos na Praia da Vitória, Terceira, Açores

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Research paper thumbnail of Primary production analysis within the Portuguese coastal zone using mathematical modelling based on satellite data

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...

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Research paper thumbnail of Wave Propagation on a Flume: Physical Modelling

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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Research paper thumbnail of Risk assessment methodology for the overtopping of maritime structures. application to the port and bay of Praia da Vitória, Azores, Portuga

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Research paper thumbnail of Managing wave-induced risks in port operations

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Research paper thumbnail of Application to the Port of Sines of a new tool for risk assessment in port navigation

Journal of Coastal Conservation, 2012

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Research paper thumbnail of Numerical Model of Constrained Wave Energy Hyperbaric Converter under Full-Scale Sea Wave Conditions

Journal of Marine Science and Engineering

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...

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Research paper thumbnail of Wave propagation in a wave channel, physical modelling

Thermal Engineering

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Research paper thumbnail of Avaliação do risco para a navegação em dois

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Research paper thumbnail of Directional spreading model in a wave channel: Wave propagation and wave breaking

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Research paper thumbnail of Physical modelling of wave propagation and wave breaking in a wave channel

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.

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Research paper thumbnail of A Comparison of Wave Breaking with RANS and SPH numerical models

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Research paper thumbnail of Avaliação do Risco de Inundação na Praia de Vale do Lobo

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.

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Research paper thumbnail of GUIOMAR: Geo(graphical) User Interface for cOastal and MARine Modeling. Wave regime at Sines

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...

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Research paper thumbnail of Modelling of Hydrodynamics Around an Impermeable Breakwater: Comparison Between Physical and SPH Numerical Modeling

Revista de Engenharia Térmica

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.

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Research paper thumbnail of Wave interaction with a vertical wall: SPH numerical and experimental modeling

Ocean Engineering, 2014

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.

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Research paper thumbnail of Hidrodinâmica da zona oceânica adjacente à Península Ibérica

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Research paper thumbnail of Modelação matemática da hidrodinâmica e da intrusão salina no estuário do rio Douro

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Research paper thumbnail of Probabilistic assessment of the safety of sea defences using level II and level III methods

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Efeito Das Obras Da Embocadura Na Hidrodinâmica, Intrusão Salina e Dinâmica Sedimentar Do Estuário Do Rio Douro

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 ...

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Research paper thumbnail of Avaliação comparativa do risco de galgamentos na Praia da Vitória, Terceira, Açores

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Primary production analysis within the Portuguese coastal zone using mathematical modelling based on satellite data

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...

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Research paper thumbnail of Wave Propagation on a Flume: Physical Modelling

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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Research paper thumbnail of Risk assessment methodology for the overtopping of maritime structures. application to the port and bay of Praia da Vitória, Azores, Portuga

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