Articles de revistahttp://hdl.handle.net/2117/35052024-03-28T20:27:40Z2024-03-28T20:27:40ZInfluence of seagrass meadow length on beach morphodynamics: an experimental studyAstudillo Gutiérrez, Carlos SalvadorGracia Garcia, VicenteCáceres Rabionet, IvánSierra Pedrico, Juan PabloSánchez-Arcilla Conejo, Agustínhttp://hdl.handle.net/2117/4054732024-03-27T14:30:21Z2024-03-27T14:27:42ZInfluence of seagrass meadow length on beach morphodynamics: an experimental study
Astudillo Gutiérrez, Carlos Salvador; Gracia Garcia, Vicente; Cáceres Rabionet, Iván; Sierra Pedrico, Juan Pablo; Sánchez-Arcilla Conejo, Agustín
A novel flume experiment was conducted to compare the sheltering effect of surrogate seagrass meadows of two different lengths against a bare beach (benchmark). The analyses focused on assessing the impact of meadow cross-shore extent on wave height attenuation, behaviour of wave orbital velocity components, sediment transport, and shoreline erosion. Throughout the tests conducted in the large-scale CIEM wave flume at LIM/UPC Barcelona, meadow density and submergence ratio remained constant, while irregular waves were run over an initial 1:15 sand beach profile. In both meadow layouts, a persistent decrease in wave height from the offshore area in front of the meadow to the breaking zone was found. This reduction was directly correlated with the length of the seagrass meadow. As a result of the reduction in wave energy, less erosion occurred at the shoreline in accordance with the decrease in wave height. The mean velocities exhibited changes in the velocity profile from the meadow area to the immediate zone behind the meadow, a phenomenon not observed in more onshoreward positions. Orbital velocities displayed a reduction exclusively for the long meadow case. This decrease was persistent up to the breaking zone. As a consequence of these changes, the long meadow layout led to a decrease in the volume of sediment transport and a breaker bar closer to the shoreline. The short meadow layout resulted in a higher volume of sediment transport compared to the long meadow layout, although still less than the benchmark layout. Furthermore, in the short meadow layout, the final bar was situated in a location similar to that observed in the benchmark layout.
2024-03-27T14:27:42ZAstudillo Gutiérrez, Carlos SalvadorGracia Garcia, VicenteCáceres Rabionet, IvánSierra Pedrico, Juan PabloSánchez-Arcilla Conejo, AgustínA novel flume experiment was conducted to compare the sheltering effect of surrogate seagrass meadows of two different lengths against a bare beach (benchmark). The analyses focused on assessing the impact of meadow cross-shore extent on wave height attenuation, behaviour of wave orbital velocity components, sediment transport, and shoreline erosion. Throughout the tests conducted in the large-scale CIEM wave flume at LIM/UPC Barcelona, meadow density and submergence ratio remained constant, while irregular waves were run over an initial 1:15 sand beach profile. In both meadow layouts, a persistent decrease in wave height from the offshore area in front of the meadow to the breaking zone was found. This reduction was directly correlated with the length of the seagrass meadow. As a result of the reduction in wave energy, less erosion occurred at the shoreline in accordance with the decrease in wave height. The mean velocities exhibited changes in the velocity profile from the meadow area to the immediate zone behind the meadow, a phenomenon not observed in more onshoreward positions. Orbital velocities displayed a reduction exclusively for the long meadow case. This decrease was persistent up to the breaking zone. As a consequence of these changes, the long meadow layout led to a decrease in the volume of sediment transport and a breaker bar closer to the shoreline. The short meadow layout resulted in a higher volume of sediment transport compared to the long meadow layout, although still less than the benchmark layout. Furthermore, in the short meadow layout, the final bar was situated in a location similar to that observed in the benchmark layout.Numerical simulation of a flexible net in currents with the smoothed particle hydrodynamics methodGonzález Ávalos, Raúl AlexisMartinez Estevez, IvanDomínguez Alonso, José ManuelAltomare, CorradoGironella Cobos, XavierCabrera Crespo, Alejandro Jacobohttp://hdl.handle.net/2117/4050202024-03-25T01:37:19Z2024-03-20T13:30:02ZNumerical simulation of a flexible net in currents with the smoothed particle hydrodynamics method
González Ávalos, Raúl Alexis; Martinez Estevez, Ivan; Domínguez Alonso, José Manuel; Altomare, Corrado; Gironella Cobos, Xavier; Cabrera Crespo, Alejandro Jacobo
The aim of this study is to evaluate the applicability and suitability of the Smoothed Particle Hydrodynamics (SPH) method in modelling a flexible flat net in currents. SPH is a meshless Lagrangian method that discretises the system into particles, making it particularly suitable for modelling turbulent and highly nonlinear flows with the presence of a free surface. For the modelling of the flexible net, a methodology is proposed that uses fluid-driven elements (spheres) and dynamic links to discretise the geometry of the net within the SPH framework. This numerical approach allows the determination of the deformation of the net elements in the numerical model, the analysis of the fluid velocity field through the discrete elements and the calculation of the drag forces on the system under different flow regimes. The proposed method for the numerical modelling of the net is based on the coupling of DualSPHysics and MoorDyn+. DualSPHysics is a fully Lagrangian and meshless open-source code based on weakly compressible SPH that solves the fluid-structure interaction. MoorDyn+ is a dynamic library based on a lumped-mass numerical model, which solves tensions in the lines and allows the establishment of connections between the floating elements. In addition, an in-house algorithm is used to generate the configuration of the net in the numerical model, preserving the hydrodynamic and structural properties of the studied net. The proposed method for the discretisation of the net is validated by a comparative analysis of the drag forces obtained in the numerical model for a flat net fixed in a rigid frame, with different solidity values and those obtained by analytical solutions. Then, the method is applied to simulate a flexible flat net in steady currents with different velocities. The results are compared with those obtained from physical modelling tests and show a satisfactory agreement of the proposed method in the majority of the cases analysed, with a difference of less than 11%.
2024-03-20T13:30:02ZGonzález Ávalos, Raúl AlexisMartinez Estevez, IvanDomínguez Alonso, José ManuelAltomare, CorradoGironella Cobos, XavierCabrera Crespo, Alejandro JacoboThe aim of this study is to evaluate the applicability and suitability of the Smoothed Particle Hydrodynamics (SPH) method in modelling a flexible flat net in currents. SPH is a meshless Lagrangian method that discretises the system into particles, making it particularly suitable for modelling turbulent and highly nonlinear flows with the presence of a free surface. For the modelling of the flexible net, a methodology is proposed that uses fluid-driven elements (spheres) and dynamic links to discretise the geometry of the net within the SPH framework. This numerical approach allows the determination of the deformation of the net elements in the numerical model, the analysis of the fluid velocity field through the discrete elements and the calculation of the drag forces on the system under different flow regimes. The proposed method for the numerical modelling of the net is based on the coupling of DualSPHysics and MoorDyn+. DualSPHysics is a fully Lagrangian and meshless open-source code based on weakly compressible SPH that solves the fluid-structure interaction. MoorDyn+ is a dynamic library based on a lumped-mass numerical model, which solves tensions in the lines and allows the establishment of connections between the floating elements. In addition, an in-house algorithm is used to generate the configuration of the net in the numerical model, preserving the hydrodynamic and structural properties of the studied net. The proposed method for the discretisation of the net is validated by a comparative analysis of the drag forces obtained in the numerical model for a flat net fixed in a rigid frame, with different solidity values and those obtained by analytical solutions. Then, the method is applied to simulate a flexible flat net in steady currents with different velocities. The results are compared with those obtained from physical modelling tests and show a satisfactory agreement of the proposed method in the majority of the cases analysed, with a difference of less than 11%.Copernicus Ocean State Report, issue 6. Chapter 4: Specific events during the year 2020Álvarez Fanjul, EnriquePérez Gómez, BegoñaAlonso Muñoyerro, Marta de AlfonsoLorente Jiménez, PabloGarcía Sotillo, MarcosLin Ye, JueAznar Lecocq, RolandRuiz Gil de la Serna, María IsabelPérez Rubio, SusanaClementi, EmanuelaMestres Ridge, MarcMösso Aranda, Césarhttp://hdl.handle.net/2117/4047092024-03-17T05:16:06Z2024-03-15T11:10:24ZCopernicus Ocean State Report, issue 6. Chapter 4: Specific events during the year 2020
Álvarez Fanjul, Enrique; Pérez Gómez, Begoña; Alonso Muñoyerro, Marta de Alfonso; Lorente Jiménez, Pablo; García Sotillo, Marcos; Lin Ye, Jue; Aznar Lecocq, Roland; Ruiz Gil de la Serna, María Isabel; Pérez Rubio, Susana; Clementi, Emanuela; Mestres Ridge, Marc; Mösso Aranda, César
2024-03-15T11:10:24ZÁlvarez Fanjul, EnriquePérez Gómez, BegoñaAlonso Muñoyerro, Marta de AlfonsoLorente Jiménez, PabloGarcía Sotillo, MarcosLin Ye, JueAznar Lecocq, RolandRuiz Gil de la Serna, María IsabelPérez Rubio, SusanaClementi, EmanuelaMestres Ridge, MarcMösso Aranda, CésarEffectiveness of dune reconstruction and beach nourishment to mitigate coastal erosion of the Ebro Delta (Spain)Costa, Giuseppe PioMarino, MassimilianoCáceres Rabionet, IvánMusumeci, Rosaria Esterhttp://hdl.handle.net/2117/4040462024-03-11T00:14:36Z2024-03-08T19:58:42ZEffectiveness of dune reconstruction and beach nourishment to mitigate coastal erosion of the Ebro Delta (Spain)
Costa, Giuseppe Pio; Marino, Massimiliano; Cáceres Rabionet, Iván; Musumeci, Rosaria Ester
Coastal areas facing increasing erosion are resorting to sand displacement strategies to mitigate the erosive impact, which is exacerbated by climate change. In the face of climate change, coastal managers are more frequently resorting to sand displacement strategies to recover eroding coastlines. These vulnerable coastal zones require innovative approaches to minimize the need for frequent sand replenishment, extend their effectiveness and lower their maintenance expenses. This study undertakes a comparison of four primary nourishment strategies—a conventional uniform nourishment technique and the placement of a single sand dune evaluated at three different positions—in contrast to a scenario where no intervention is carried out. The investigation employs the XBeach numerical model to assess the outcomes of these diverse strategies under both low- and high-energetic storm conditions. The case study is a degraded coastal beach in the Ebro Delta (Spain). The results reveal a significant decrease in erosion when the dune is positioned closest to the shoreline. However, this erosion mitigation effect diminishes as the dune is situated further inland. Conversely, the sand nourishment measure exhibits minimal fluctuations in the volume of eroded sand when compared to the scenario with no intervention.
2024-03-08T19:58:42ZCosta, Giuseppe PioMarino, MassimilianoCáceres Rabionet, IvánMusumeci, Rosaria EsterCoastal areas facing increasing erosion are resorting to sand displacement strategies to mitigate the erosive impact, which is exacerbated by climate change. In the face of climate change, coastal managers are more frequently resorting to sand displacement strategies to recover eroding coastlines. These vulnerable coastal zones require innovative approaches to minimize the need for frequent sand replenishment, extend their effectiveness and lower their maintenance expenses. This study undertakes a comparison of four primary nourishment strategies—a conventional uniform nourishment technique and the placement of a single sand dune evaluated at three different positions—in contrast to a scenario where no intervention is carried out. The investigation employs the XBeach numerical model to assess the outcomes of these diverse strategies under both low- and high-energetic storm conditions. The case study is a degraded coastal beach in the Ebro Delta (Spain). The results reveal a significant decrease in erosion when the dune is positioned closest to the shoreline. However, this erosion mitigation effect diminishes as the dune is situated further inland. Conversely, the sand nourishment measure exhibits minimal fluctuations in the volume of eroded sand when compared to the scenario with no intervention.Influence of beach slope on morphological changes and dediment transport under irregular wavesDionisio António, Saravan der Werf, JebbeHorstman, ErikCáceres Rabionet, IvánAlsina Torrent, José Maríavan der Zanden, JoepHulscher, Suzanne J.M.H.http://hdl.handle.net/2117/4038742024-03-11T00:14:04Z2024-03-06T13:20:56ZInfluence of beach slope on morphological changes and dediment transport under irregular waves
Dionisio António, Sara; van der Werf, Jebbe; Horstman, Erik; Cáceres Rabionet, Iván; Alsina Torrent, José María; van der Zanden, Joep; Hulscher, Suzanne J.M.H.
This paper presents new data from large-scale wave flume experiments. It shows the beach profile evolution and sediment transport for two different bed slopes (1:15 and 1:25), and three irregular high-energy erosive wave conditions and one low-energy accretive wave condition. The bulk cross-shore net sediment transport was investigated for the total active profile and for the surf and swash zone separately. It is shown that the steep slope is morphologically more active than the gentle slope, with faster and more pronounced morphological changes and larger sediment transport rates. For both slopes, the total and surf zone net sediment transport were offshore-directed for erosive waves and onshore-directed for the accretive wave condition. However, the net swash zone transport for the erosive wave conditions was offshore-directed for the steep slope and onshore-directed for the gentle slope. The direction and magnitude of the total and surf zone sediment transport correlate well with the slope-corrected Dean criterion with increasing offshore-directed sediment transport (erosion) observed for increasing wave energy and bed slope. This relation does not hold for the swash zone sediment transport along the gentle slope, suggesting that swash zone sediment transport processes are not well captured when using a simple predictor such as the (modified) Dean number. Differences in sediment transport in the swash for the different slopes are likely influenced by differences in incoming wave energy, wave–swash interactions and the relative importance of long- and short-waves.
2024-03-06T13:20:56ZDionisio António, Saravan der Werf, JebbeHorstman, ErikCáceres Rabionet, IvánAlsina Torrent, José Maríavan der Zanden, JoepHulscher, Suzanne J.M.H.This paper presents new data from large-scale wave flume experiments. It shows the beach profile evolution and sediment transport for two different bed slopes (1:15 and 1:25), and three irregular high-energy erosive wave conditions and one low-energy accretive wave condition. The bulk cross-shore net sediment transport was investigated for the total active profile and for the surf and swash zone separately. It is shown that the steep slope is morphologically more active than the gentle slope, with faster and more pronounced morphological changes and larger sediment transport rates. For both slopes, the total and surf zone net sediment transport were offshore-directed for erosive waves and onshore-directed for the accretive wave condition. However, the net swash zone transport for the erosive wave conditions was offshore-directed for the steep slope and onshore-directed for the gentle slope. The direction and magnitude of the total and surf zone sediment transport correlate well with the slope-corrected Dean criterion with increasing offshore-directed sediment transport (erosion) observed for increasing wave energy and bed slope. This relation does not hold for the swash zone sediment transport along the gentle slope, suggesting that swash zone sediment transport processes are not well captured when using a simple predictor such as the (modified) Dean number. Differences in sediment transport in the swash for the different slopes are likely influenced by differences in incoming wave energy, wave–swash interactions and the relative importance of long- and short-waves.Numerical validations and investigation of a semi-submersible floating offshore wind turbine platform interacting with ocean waves using an SPH frameworkTagliafierro, BonaventuraKarimirad, MadjidAltomare, CorradoGöteman, MalinMartinez Estevez, IvanCapasso, SalvatoreDomínguez Alonso, José ManuelViccione, GiacomoGómez Gesteira, MonchoCabrera Crespo, Alejandro Jacobohttp://hdl.handle.net/2117/4038432024-03-11T00:14:04Z2024-03-06T11:59:55ZNumerical validations and investigation of a semi-submersible floating offshore wind turbine platform interacting with ocean waves using an SPH framework
Tagliafierro, Bonaventura; Karimirad, Madjid; Altomare, Corrado; Göteman, Malin; Martinez Estevez, Ivan; Capasso, Salvatore; Domínguez Alonso, José Manuel; Viccione, Giacomo; Gómez Gesteira, Moncho; Cabrera Crespo, Alejandro Jacobo
In this work, we propose numerical validations of the DeepCwind semi-submersible floating platform configuration for a single horizontal axis wind turbine using data from two experimental testing investigations. A Smoothed Particle Hydrodynamics solver is employed to estimate fluid induced loads, whereas the mooring connections are handled via an external library. The first validation setup is based on the DeepCwind offshore wind semi-submersible concept moored with a system of taut-lines and tested for free-decay surge and heave motion (OC6-Phase Ia). The damping evaluation yields a fair estimation of the heave damping behavior, whereas much more dissipation is experienced for the surge. The second validation features a full hydrodynamic characterization of the frequency-related load patterns induced by three different sea-state representations (mono-, bi-chromatic, and irregular waves) (OC6-Phase Ib). The model accurately matches the hydrodynamic load estimation for the whole spectrum of investigated wave components, perfectly capturing the non-linear behavior shown by the considered wave patterns. This work concludes with a systematic study on the motion response, mooring tension, pressure and vorticity, suggesting that: the wave steepness criterion alone cannot identify the most restrictive load case; waves with spectral characteristics close to the heave resonance period lead to higher tensions in the mooring systems, whereas the maximum fluid-induced loads on the hull are decoupled from displacement peaks, showing an average reduction of 30% with respect to the maxima; very steep waves maximize the likelihood of wave overtopping and slamming loads, resulting in locally induced overpressure on the free-board of up to 100% higher than expected for similar wave heights with milder profiles. The input data for these last tests is released for the sake of reproduction.
2024-03-06T11:59:55ZTagliafierro, BonaventuraKarimirad, MadjidAltomare, CorradoGöteman, MalinMartinez Estevez, IvanCapasso, SalvatoreDomínguez Alonso, José ManuelViccione, GiacomoGómez Gesteira, MonchoCabrera Crespo, Alejandro JacoboIn this work, we propose numerical validations of the DeepCwind semi-submersible floating platform configuration for a single horizontal axis wind turbine using data from two experimental testing investigations. A Smoothed Particle Hydrodynamics solver is employed to estimate fluid induced loads, whereas the mooring connections are handled via an external library. The first validation setup is based on the DeepCwind offshore wind semi-submersible concept moored with a system of taut-lines and tested for free-decay surge and heave motion (OC6-Phase Ia). The damping evaluation yields a fair estimation of the heave damping behavior, whereas much more dissipation is experienced for the surge. The second validation features a full hydrodynamic characterization of the frequency-related load patterns induced by three different sea-state representations (mono-, bi-chromatic, and irregular waves) (OC6-Phase Ib). The model accurately matches the hydrodynamic load estimation for the whole spectrum of investigated wave components, perfectly capturing the non-linear behavior shown by the considered wave patterns. This work concludes with a systematic study on the motion response, mooring tension, pressure and vorticity, suggesting that: the wave steepness criterion alone cannot identify the most restrictive load case; waves with spectral characteristics close to the heave resonance period lead to higher tensions in the mooring systems, whereas the maximum fluid-induced loads on the hull are decoupled from displacement peaks, showing an average reduction of 30% with respect to the maxima; very steep waves maximize the likelihood of wave overtopping and slamming loads, resulting in locally induced overpressure on the free-board of up to 100% higher than expected for similar wave heights with milder profiles. The input data for these last tests is released for the sake of reproduction.Transport and accumulation of floating marine litter in the Black Sea: insights from numerical modelingCastro Rosero, Leidy MaricelaHernandez, IvanAlsina Torrent, José MaríaEspino Infantes, Manuelhttp://hdl.handle.net/2117/3998142024-01-21T19:34:21Z2024-01-18T13:55:03ZTransport and accumulation of floating marine litter in the Black Sea: insights from numerical modeling
Castro Rosero, Leidy Maricela; Hernandez, Ivan; Alsina Torrent, José María; Espino Infantes, Manuel
Floating marine litter (FML) is a global problem with significant risks to marine life and human health. In semi-enclosed basins like the Black Sea, slow water replenishment and strong input from European rivers create conditions that can lead to the accumulation of FML. This study aims to validate and utilize an FML dispersion and accumulation numerical model. Additionally, it assesses the influence of Stokes drift on the accumulation patterns of marine litter in the Black Sea, focusing on the contribution from the main river discharge points.
2024-01-18T13:55:03ZCastro Rosero, Leidy MaricelaHernandez, IvanAlsina Torrent, José MaríaEspino Infantes, ManuelFloating marine litter (FML) is a global problem with significant risks to marine life and human health. In semi-enclosed basins like the Black Sea, slow water replenishment and strong input from European rivers create conditions that can lead to the accumulation of FML. This study aims to validate and utilize an FML dispersion and accumulation numerical model. Additionally, it assesses the influence of Stokes drift on the accumulation patterns of marine litter in the Black Sea, focusing on the contribution from the main river discharge points.Understanding allochthonous marine litter in a protected area in the Amazon coastFerreira da Silva Assis, LucianeCajueiro Carneiro Pereira, LuciJiménez Quintana, José AntonioRibeiro Padilha da Silva, Brendada Costa Pereira, Remo Marinhoda Costa, Rauquírio Marinhohttp://hdl.handle.net/2117/3989632024-01-17T13:15:37Z2024-01-09T20:23:59ZUnderstanding allochthonous marine litter in a protected area in the Amazon coast
Ferreira da Silva Assis, Luciane; Cajueiro Carneiro Pereira, Luci; Jiménez Quintana, José Antonio; Ribeiro Padilha da Silva, Brenda; da Costa Pereira, Remo Marinho; da Costa, Rauquírio Marinho
Studies on international waste on the Amazon coast are lacking, leaving a substantial knowledge gap concerning the socioeconomic, cultural, and environmental repercussion of this issue. In this context, the objective of this study is to comprehensively characterize and trace the origins of allochthonous litter discovered on a beach situated within a Protected Area. Given this, the hypothesis of this study is that the international litters comes from vessels operating in the region. A total of 384 containers were collected, originating from 36 countries, with those located in Asia and Africa showing the highest prevalence. Among the bottles with identified expiration dates, 76 % are newly arrived, confirming our hypothesis. The presence of older waste may result from a combination of the absence of beach cleaning public services and local dynamic processes. While international engagement is necessary, local communities, along with the scientific community, have taken proactive measures to address the problem.
2024-01-09T20:23:59ZFerreira da Silva Assis, LucianeCajueiro Carneiro Pereira, LuciJiménez Quintana, José AntonioRibeiro Padilha da Silva, Brendada Costa Pereira, Remo Marinhoda Costa, Rauquírio MarinhoStudies on international waste on the Amazon coast are lacking, leaving a substantial knowledge gap concerning the socioeconomic, cultural, and environmental repercussion of this issue. In this context, the objective of this study is to comprehensively characterize and trace the origins of allochthonous litter discovered on a beach situated within a Protected Area. Given this, the hypothesis of this study is that the international litters comes from vessels operating in the region. A total of 384 containers were collected, originating from 36 countries, with those located in Asia and Africa showing the highest prevalence. Among the bottles with identified expiration dates, 76 % are newly arrived, confirming our hypothesis. The presence of older waste may result from a combination of the absence of beach cleaning public services and local dynamic processes. While international engagement is necessary, local communities, along with the scientific community, have taken proactive measures to address the problem.Large-scale wave breaking over a barred beach: SPH numerical simulation and comparison with experimentsAltomare, CorradoScandura, PietroCáceres Rabionet, IvánVan Der A, DominicViccione, Giacomohttp://hdl.handle.net/2117/3989502024-01-17T13:20:51Z2024-01-09T17:44:06ZLarge-scale wave breaking over a barred beach: SPH numerical simulation and comparison with experiments
Altomare, Corrado; Scandura, Pietro; Cáceres Rabionet, Iván; Van Der A, Dominic; Viccione, Giacomo
Wave breaking plays a crucial role in several areas of interest in coastal engineering, such as flooding, wave loading on structures and coastal morphodynamics. In the present study, Smoothed Particle Hydrodynamics (SPH) simulations of monochromatic waves breaking over a rigid barred beach profile are presented. The numerical results comprise wave heights, phase average velocities, time-averaged velocities, vorticity dynamics, and radiation stress, and are validated versus detailed water surface and velocity measurements carried out in a large-scale laboratory wave flume. The experimental data include velocity profiles below the wave trough measured at 22 cross-shore locations in the bar region using acoustic and optical techniques and water surface elevation measured along the flume using resistive gauges, acoustic gauges and pressure sensors. This study is novel in that it analyses the hydrodynamics of wave breaking at a scale close to natural conditions, thus significantly reducing the scale effects of most previous studies, which were conducted at a much smaller scale. In general, water surface elevation is well reproduced by SPH, but discrepancies with the experiments are observed in the highly aerated breaking region, depending on the measurement technique. The SPH simulation shows that wave breaking generates a recirculating cell, immediately above the trough of the bar. Within this cell, near the bed, the flow is offshore directed, while in the upper part of the water column it is onshore oriented. This flow is probably one of the mechanisms that determine the growth of the bar when the bed is made of mobile material. The time-averaged velocity profiles are reproduced with reasonable accuracy by the numerical model, except at the edges of the bar trough, where discrepancies with respect to the measurements are observed. The numerical results provide detailed information, particularly interesting in areas lacking experimental data. One of the main surprising features revealed by the SPH simulations is the generation of a vortex pair that occurs when the cavities formed by the plunge jet collapse. These vortices can occasionally deform the free surface. Based on the numerical results, an analysis of the terms contributing to radiation stress shows that the product between the horizontal and the vertical velocity components does not make a significant contribution. Through comparisons with the SPH results, it is observed that the linear wave theory provides correct estimates of the radiation stress in the shoaling region sufficiently far from the bar crest, while in the surf zone it reproduces incorrect results. Information about the appropriate SPH model setup to correctly capture the physical processes involved in the breaking phenomenon are also presented.
2024-01-09T17:44:06ZAltomare, CorradoScandura, PietroCáceres Rabionet, IvánVan Der A, DominicViccione, GiacomoWave breaking plays a crucial role in several areas of interest in coastal engineering, such as flooding, wave loading on structures and coastal morphodynamics. In the present study, Smoothed Particle Hydrodynamics (SPH) simulations of monochromatic waves breaking over a rigid barred beach profile are presented. The numerical results comprise wave heights, phase average velocities, time-averaged velocities, vorticity dynamics, and radiation stress, and are validated versus detailed water surface and velocity measurements carried out in a large-scale laboratory wave flume. The experimental data include velocity profiles below the wave trough measured at 22 cross-shore locations in the bar region using acoustic and optical techniques and water surface elevation measured along the flume using resistive gauges, acoustic gauges and pressure sensors. This study is novel in that it analyses the hydrodynamics of wave breaking at a scale close to natural conditions, thus significantly reducing the scale effects of most previous studies, which were conducted at a much smaller scale. In general, water surface elevation is well reproduced by SPH, but discrepancies with the experiments are observed in the highly aerated breaking region, depending on the measurement technique. The SPH simulation shows that wave breaking generates a recirculating cell, immediately above the trough of the bar. Within this cell, near the bed, the flow is offshore directed, while in the upper part of the water column it is onshore oriented. This flow is probably one of the mechanisms that determine the growth of the bar when the bed is made of mobile material. The time-averaged velocity profiles are reproduced with reasonable accuracy by the numerical model, except at the edges of the bar trough, where discrepancies with respect to the measurements are observed. The numerical results provide detailed information, particularly interesting in areas lacking experimental data. One of the main surprising features revealed by the SPH simulations is the generation of a vortex pair that occurs when the cavities formed by the plunge jet collapse. These vortices can occasionally deform the free surface. Based on the numerical results, an analysis of the terms contributing to radiation stress shows that the product between the horizontal and the vertical velocity components does not make a significant contribution. Through comparisons with the SPH results, it is observed that the linear wave theory provides correct estimates of the radiation stress in the shoaling region sufficiently far from the bar crest, while in the surf zone it reproduces incorrect results. Information about the appropriate SPH model setup to correctly capture the physical processes involved in the breaking phenomenon are also presented.Assessment of trophic status in Amazonian estuaries: a reinterpretation of TRIX values in mangrove estuariesCajueiro Carneiro Pereira, LuciJiménez Quintana, José AntonioGonzalez Pineda, MarionaRodrigues da Costa, Adila Kellyda Silva Sousa, Natalia do SocorroGomes de Oliveira, Antonio rafaelda Costa, Rauquirio Marinhohttp://hdl.handle.net/2117/3953812023-10-29T23:16:17Z2023-10-25T17:28:36ZAssessment of trophic status in Amazonian estuaries: a reinterpretation of TRIX values in mangrove estuaries
Cajueiro Carneiro Pereira, Luci; Jiménez Quintana, José Antonio; Gonzalez Pineda, Mariona; Rodrigues da Costa, Adila Kelly; da Silva Sousa, Natalia do Socorro; Gomes de Oliveira, Antonio rafael; da Costa, Rauquirio Marinho
stal waters is a key issue in environmental management, and for this purpose, in addition to other methods, indices have been widely used to evaluate the trophic status of these waters (e.g., Bricker et al., 2003). Among the various existing indices to characterize the trophic status of an estuary (Zaldívar et al., 2008; Borja et al., 2012), the Trophic Status Index (TRIX) developed by Vollenweider et al. (1998) has been widely used because it aggregates the main cause-effect variables of eutrophi-cation, including pressure response, biological response, and environ-mental disturbance (e.g., Devlin et al., 2011; Jayachandran and Bijoy Nandan, 2011; Cabrita et al., 2015). The present study evaluates and compares the trophic state of two estuaries located on the Amazon coast.
2023-10-25T17:28:36ZCajueiro Carneiro Pereira, LuciJiménez Quintana, José AntonioGonzalez Pineda, MarionaRodrigues da Costa, Adila Kellyda Silva Sousa, Natalia do SocorroGomes de Oliveira, Antonio rafaelda Costa, Rauquirio Marinhostal waters is a key issue in environmental management, and for this purpose, in addition to other methods, indices have been widely used to evaluate the trophic status of these waters (e.g., Bricker et al., 2003). Among the various existing indices to characterize the trophic status of an estuary (Zaldívar et al., 2008; Borja et al., 2012), the Trophic Status Index (TRIX) developed by Vollenweider et al. (1998) has been widely used because it aggregates the main cause-effect variables of eutrophi-cation, including pressure response, biological response, and environ-mental disturbance (e.g., Devlin et al., 2011; Jayachandran and Bijoy Nandan, 2011; Cabrita et al., 2015). The present study evaluates and compares the trophic state of two estuaries located on the Amazon coast.