Pub Date : 2026-03-15Epub Date: 2025-12-11DOI: 10.1016/j.coastaleng.2025.104934
Rafail Ioannou , Vasiliki Stratigaki , Eva Loukogeorgaki , Peter Troch
Fluid-flexible floating structure interaction studies in Computational Fluid Dynamics (CFD) remain predominantly two dimensionals, limiting the exploration of three dimensional effects crucial for the design of Very Flexible Floating Structures (VFFSs). To address this gap, this work extends a previously developed Applied Element Method (AEM) beam formulation into a plate formulation within the coupling of the weakly compressible Smoothed Particle Hydrodynamics (SPH) solver of DualSPHysics and the Multibody Dynamics (MBD) module of Project Chrono. The new structural scheme demonstrates comparable accuracy to established non-linear shell formulations in problems dominated by large displacements. Incorporated into an SPH variable resolution scheme for the fluid phase, the proposed formulation is validated experimentally for flexible floating plates, confirming both the accuracy of the three dimensional AEM framework in fluids and the robustness of the coupling under variable resolution conditions. Thus, the developed fluid-flexible structure interaction model establishes a foundation for advancing the design analysis of VFFSs, including future applications with complex mooring line configurations or large-scale interconnected modular arrays.
{"title":"A novel thin floating plate formulation in SPH: Extension to a three dimensional Applied Element Method framework","authors":"Rafail Ioannou , Vasiliki Stratigaki , Eva Loukogeorgaki , Peter Troch","doi":"10.1016/j.coastaleng.2025.104934","DOIUrl":"10.1016/j.coastaleng.2025.104934","url":null,"abstract":"<div><div>Fluid-flexible floating structure interaction studies in Computational Fluid Dynamics (CFD) remain predominantly two dimensionals, limiting the exploration of three dimensional effects crucial for the design of Very Flexible Floating Structures (VFFSs). To address this gap, this work extends a previously developed Applied Element Method (AEM) beam formulation into a plate formulation within the coupling of the weakly compressible Smoothed Particle Hydrodynamics (SPH) solver of DualSPHysics and the Multibody Dynamics (MBD) module of Project Chrono. The new structural scheme demonstrates comparable accuracy to established non-linear shell formulations in problems dominated by large displacements. Incorporated into an SPH variable resolution scheme for the fluid phase, the proposed formulation is validated experimentally for flexible floating plates, confirming both the accuracy of the three dimensional AEM framework in fluids and the robustness of the coupling under variable resolution conditions. Thus, the developed fluid-flexible structure interaction model establishes a foundation for advancing the design analysis of VFFSs, including future applications with complex mooring line configurations or large-scale interconnected modular arrays.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104934"},"PeriodicalIF":4.5,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145749734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Over the past decades, seagrasses have drastically declined worldwide, reducing their capacity to regulate flow conditions. Intertidal species have been particularly affected by this decline, yet there is limited understanding of how intertidal seagrass loss influences hydrodynamics in shallow coastal lagoons. In this study, we use a 3D flow-vegetation model that accounts for vegetation effect on mean and turbulent flow, as well as flow-induced leaf bending, to investigate how tidal hydrodynamics respond to seasonal and multi-decadal changes in intertidal seagrass characteristics. The model is applied to the Arcachon lagoon (France), colonized by extensive Zostera noltei and Zostera marina meadows. This study reveals that a short-leaf and flexible seagrass species such as Zostera noltei can regulate tidal hydrodynamics throughout the lagoon due to the presence of broad and dense meadows on the tidal flats. In summer, seagrass decline leads to a significant increase in the 75th percentile in bottom flow velocities (+100 %) on the tidal flats, but to a decrease in the channels (−20 %). However, in winter, the response of tidal hydrodynamics to the reduction in seagrass coverage is far less pronounced. Comparison of simulated scenarios reveals that the multi-decadal decline of Zostera meadows with summer characteristics and the seasonal loss between summer and winter lead to modifications in tidal-flow parameters (current velocities, tidal asymmetry, high-tide water level) of a comparable magnitude. These changes in hydrodynamics likely enhance suspended sediment concentration, reducing light availability, contributing to further seagrass loss, and modifying sediment management for stakeholders due to enhanced siltation in channels.
{"title":"Drastic changes in tidal hydrodynamics following seagrass decline and their seasonal variations in a shallow lagoon","authors":"Arnaud Le Pevedic , Mathis Cognat , Aldo Sottolichio , Florian Ganthy","doi":"10.1016/j.coastaleng.2026.104948","DOIUrl":"10.1016/j.coastaleng.2026.104948","url":null,"abstract":"<div><div>Over the past decades, seagrasses have drastically declined worldwide, reducing their capacity to regulate flow conditions. Intertidal species have been particularly affected by this decline, yet there is limited understanding of how intertidal seagrass loss influences hydrodynamics in shallow coastal lagoons. In this study, we use a 3D flow-vegetation model that accounts for vegetation effect on mean and turbulent flow, as well as flow-induced leaf bending, to investigate how tidal hydrodynamics respond to seasonal and multi-decadal changes in intertidal seagrass characteristics. The model is applied to the Arcachon lagoon (France), colonized by extensive <em>Zostera noltei</em> and <em>Zostera marina</em> meadows. This study reveals that a short-leaf and flexible seagrass species such as <em>Zostera noltei</em> can regulate tidal hydrodynamics throughout the lagoon due to the presence of broad and dense meadows on the tidal flats. In summer, seagrass decline leads to a significant increase in the 75th percentile in bottom flow velocities (+100 %) on the tidal flats, but to a decrease in the channels (−20 %). However, in winter, the response of tidal hydrodynamics to the reduction in seagrass coverage is far less pronounced. Comparison of simulated scenarios reveals that the multi-decadal decline of <em>Zostera</em> meadows with summer characteristics and the seasonal loss between summer and winter lead to modifications in tidal-flow parameters (current velocities, tidal asymmetry, high-tide water level) of a comparable magnitude. These changes in hydrodynamics likely enhance suspended sediment concentration, reducing light availability, contributing to further seagrass loss, and modifying sediment management for stakeholders due to enhanced siltation in channels.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104948"},"PeriodicalIF":4.5,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145976563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2026-01-06DOI: 10.1016/j.coastaleng.2026.104947
Zhaopei Huang , Gang Wang , Songgui Chen , Hui Fang , Aifeng Tao
The distinct morphology of atolls drives complex three-dimensional hydrodynamics, yet field measurements in these remote environments remain scarce, and numerical models often fail to accurately capture key processes such as wave breaking on steep reef faces. To address this gap, we conducted physical experiments in a wave basin to investigate the propagation of solitary waves across a three-dimensional elliptical atoll under varying water depths and incident wave heights. Results show significant wave reflection, shoaling, and refraction as waves traverse across the atoll. Distinct hydraulic jumps, surge waves, and crest line lag were observed when solitary waves propagated into the lagoon over the emergent reef flat with h = 25 cm and 30 cm. Increased water depth from h = 25 cm to h = 30 cm or 35 cm enhances overtopping at the rear of the lagoon and advances its timing, transforming the leeward wave field from the converged diffracted waves to overtopping transmitted lagoon waves. Importantly, the wave height distribution depends critically on the water depth. When the atoll is emergent with h = 25 cm or 30 cm, wave heights are larger on the windward side and smaller within the lagoon and leeward region. Conversely, when the atoll is submerged with h = 35 cm, significant heights persisted windward, but larger maxima developed at the lagoon-rear and leeward sides. Notably, the measured maximum wave heights significantly exceed those from previous flume studies by a factor of ∼1.4 when the reef flat is at still water level with h = 30 cm and by a factor of ∼2.3 when submerged with h = 35 cm, which is attributed to the inclusion of refraction and diffraction effects in the three-dimensional basin experiments. Furthermore, solitary waves consistently trigger free oscillation within the lagoon across all depths. The free oscillation amplitude increases substantially, and higher-order modes progressively emerge with rising water depth. Future work should extend the study of solitary wave propagation over elliptical atolls by quantifying flow dynamics and incorporating surface roughness effects through high-resolution numerical simulations.
{"title":"Experimental investigation of solitary wave propagation over an elliptical atoll","authors":"Zhaopei Huang , Gang Wang , Songgui Chen , Hui Fang , Aifeng Tao","doi":"10.1016/j.coastaleng.2026.104947","DOIUrl":"10.1016/j.coastaleng.2026.104947","url":null,"abstract":"<div><div>The distinct morphology of atolls drives complex three-dimensional hydrodynamics, yet field measurements in these remote environments remain scarce, and numerical models often fail to accurately capture key processes such as wave breaking on steep reef faces. To address this gap, we conducted physical experiments in a wave basin to investigate the propagation of solitary waves across a three-dimensional elliptical atoll under varying water depths and incident wave heights. Results show significant wave reflection, shoaling, and refraction as waves traverse across the atoll. Distinct hydraulic jumps, surge waves, and crest line lag were observed when solitary waves propagated into the lagoon over the emergent reef flat with <em>h</em> = 25 cm and 30 cm. Increased water depth from <em>h</em> = 25 cm to <em>h</em> = 30 cm or 35 cm enhances overtopping at the rear of the lagoon and advances its timing, transforming the leeward wave field from the converged diffracted waves to overtopping transmitted lagoon waves. Importantly, the wave height distribution depends critically on the water depth. When the atoll is emergent with <em>h</em> = 25 cm or 30 cm, wave heights are larger on the windward side and smaller within the lagoon and leeward region. Conversely, when the atoll is submerged with <em>h</em> = 35 cm, significant heights persisted windward, but larger maxima developed at the lagoon-rear and leeward sides. Notably, the measured maximum wave heights significantly exceed those from previous flume studies by a factor of ∼1.4 when the reef flat is at still water level with <em>h</em> = 30 cm and by a factor of ∼2.3 when submerged with <em>h</em> = 35 cm, which is attributed to the inclusion of refraction and diffraction effects in the three-dimensional basin experiments. Furthermore, solitary waves consistently trigger free oscillation within the lagoon across all depths. The free oscillation amplitude increases substantially, and higher-order modes progressively emerge with rising water depth. Future work should extend the study of solitary wave propagation over elliptical atolls by quantifying flow dynamics and incorporating surface roughness effects through high-resolution numerical simulations.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104947"},"PeriodicalIF":4.5,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-11-24DOI: 10.1016/j.coastaleng.2025.104911
Samuel Rose , Chris Blenkinsopp , Andrew Barnes , William Russell , Charlie Thompson
When collecting coastal monitoring data, it is common practice to survey down to spring low tide to capture the maximum extent of the exposed subaerial beach. However, collecting topographic beach data is possible for only a few days per month. By reducing the seaward extent of the survey, the incurred costs and risks to the survey schedule could be greatly reduced. However, this would result in information loss at the lowest extremes of the subaerial beach. This study assesses the feasibility of predicting this part of the beach using deep learning neural networks based on partial beach profile data. A range of network architectures were tested alongside linear extrapolation, which was used as a baseline model. Each model was tested on three beaches with varying morphology, ranging from steep (reflective) to mildly sloping (dissipative). The presence of morphological features was found to play a dominant role in the accuracy of the predicted profiles; profiles with more pronounced cross-shore morphological features, such as sandbars, produced the highest error. While local connectivity of each network architecture was found to be the key factor in producing realistic profiles, the 1D Convolutional Neural Network was found to be the most effective with an average RMSE of between 0.026–0.119 m. This RMSE is not substantially larger than the vertical accuracy of current survey techniques (0.03 m), and the study found that errors of this magnitude have negligible effects when the survey data is used to calculate beach volumes and conduct numerical wave runup analysis to assess coastal flood risk.
{"title":"Beach monitoring: Do we need to survey to spring low tide?","authors":"Samuel Rose , Chris Blenkinsopp , Andrew Barnes , William Russell , Charlie Thompson","doi":"10.1016/j.coastaleng.2025.104911","DOIUrl":"10.1016/j.coastaleng.2025.104911","url":null,"abstract":"<div><div>When collecting coastal monitoring data, it is common practice to survey down to spring low tide to capture the maximum extent of the exposed subaerial beach. However, collecting topographic beach data is possible for only a few days per month. By reducing the seaward extent of the survey, the incurred costs and risks to the survey schedule could be greatly reduced. However, this would result in information loss at the lowest extremes of the subaerial beach. This study assesses the feasibility of predicting this part of the beach using deep learning neural networks based on partial beach profile data. A range of network architectures were tested alongside linear extrapolation, which was used as a baseline model. Each model was tested on three beaches with varying morphology, ranging from steep (reflective) to mildly sloping (dissipative). The presence of morphological features was found to play a dominant role in the accuracy of the predicted profiles; profiles with more pronounced cross-shore morphological features, such as sandbars, produced the highest error. While local connectivity of each network architecture was found to be the key factor in producing realistic profiles, the 1D Convolutional Neural Network was found to be the most effective with an average RMSE of between 0.026–0.119 m. This RMSE is not substantially larger than the vertical accuracy of current survey techniques (0.03 m), and the study found that errors of this magnitude have negligible effects when the survey data is used to calculate beach volumes and conduct numerical wave runup analysis to assess coastal flood risk.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104911"},"PeriodicalIF":4.5,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-10-09DOI: 10.1016/j.coastaleng.2025.104891
Alexandra E. Schueller , Alec Torres-Freyermuth , Jack A. Puleo
The 3rd International Workshop on Swash-Zone Processes, held in Rome, Italy in September 2024, brought together researchers to discuss the current challenges in swash-zone research. Through review presentations and a structured method, participants identified knowledge gaps and proposed ideas to address those gaps. Areas discussed included: hydrodynamics, runup, sediment transport, morphodynamics, infiltration, and the application of remote sensing and numerical modeling for swash-zone research. The workshop emphasized the need for better integration of spatially extensive data (e.g., from drones and lidar) with traditional methods, and highlighted the importance of collaboration and standardized data sharing. Additionally, discussions focused on improving numerical models of sediment dynamics and understanding of 3D hydrodynamic/morphodynamic processes. This editorial outlines the key knowledge gaps identified and the strategies proposed to address them, offering suggestions for future swash-zone processes research.
{"title":"The 3rd International Workshop on swash-zone processes","authors":"Alexandra E. Schueller , Alec Torres-Freyermuth , Jack A. Puleo","doi":"10.1016/j.coastaleng.2025.104891","DOIUrl":"10.1016/j.coastaleng.2025.104891","url":null,"abstract":"<div><div>The 3rd International Workshop on Swash-Zone Processes, held in Rome, Italy in September 2024, brought together researchers to discuss the current challenges in swash-zone research. Through review presentations and a structured method, participants identified knowledge gaps and proposed ideas to address those gaps. Areas discussed included: hydrodynamics, runup, sediment transport, morphodynamics, infiltration, and the application of remote sensing and numerical modeling for swash-zone research. The workshop emphasized the need for better integration of spatially extensive data (e.g., from drones and lidar) with traditional methods, and highlighted the importance of collaboration and standardized data sharing. Additionally, discussions focused on improving numerical models of sediment dynamics and understanding of 3D hydrodynamic/morphodynamic processes. This editorial outlines the key knowledge gaps identified and the strategies proposed to address them, offering suggestions for future swash-zone processes research.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104891"},"PeriodicalIF":4.5,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-12-17DOI: 10.1016/j.coastaleng.2025.104933
S. Terracciano , J. Montes , R. Brunetta , P. Cabrita , P. Ciavola , C. Armaroli
Beach morphology is influenced by climate-related changes, such as rising sea levels, shifting weather patterns, and storms, as well as human activities, making continuous monitoring essential for understanding its evolution. Within this dynamic context, some beaches develop morphological features that help attenuate the impact of high-energy events, effectively acting as natural barriers against coastal erosion and flooding. This research explores the role of Posidonia oceanica banquettes, natural seagrass accumulations, in influencing beach dynamics, shoreline stability, and dune development, processes that are common along much of the Mediterranean coast. The study developed a new methodological approach by integrating aerial ortophotos with high-temporal-resolution multispectral satellite imagery, to analyse beach evolution in the presence of Posidonia banquettes, with a focus on the impact of storm events. This approach examines shoreline, dune, and Posidonia accumulations through a combination of remote sensing techniques, enabling both medium-term through Satellite-Derived Shoreline (SDS) (∼10 years) and long-term analyses (∼70 years) using orthophotos. The results highlight the complex interactions between human activities, storm events, and natural processes, particularly the role of Posidonia accumulation in shaping beach and dune morphology. Medium-term analysis has offered detailed perspective on recent beach changes, illustrating fluctuations in Posidonia berms related to storm events and correlating shoreline positions with dune evolution. Meanwhile, long-term orthophotos analysis has provided insights into sediment transport dynamics and revealed trend patterns over extended timeframes. This integration of SDS data and aerial imagery leveraged the identification of “hotspot areas” by analysing the relationship between shoreline changes and dune toe retreat.
{"title":"Influence of Posidonia oceanica accumulation on beach morphodynamics: A remote sensing study","authors":"S. Terracciano , J. Montes , R. Brunetta , P. Cabrita , P. Ciavola , C. Armaroli","doi":"10.1016/j.coastaleng.2025.104933","DOIUrl":"10.1016/j.coastaleng.2025.104933","url":null,"abstract":"<div><div>Beach morphology is influenced by climate-related changes, such as rising sea levels, shifting weather patterns, and storms, as well as human activities, making continuous monitoring essential for understanding its evolution. Within this dynamic context, some beaches develop morphological features that help attenuate the impact of high-energy events, effectively acting as natural barriers against coastal erosion and flooding. This research explores the role of <em>Posidonia oceanica</em> banquettes, natural seagrass accumulations, in influencing beach dynamics, shoreline stability, and dune development, processes that are common along much of the Mediterranean coast. The study developed a new methodological approach by integrating aerial ortophotos with high-temporal-resolution multispectral satellite imagery, to analyse beach evolution in the presence of <em>Posidonia</em> banquettes, with a focus on the impact of storm events. This approach examines shoreline, dune, and Posidonia accumulations through a combination of remote sensing techniques, enabling both medium-term through Satellite-Derived Shoreline (SDS) (∼10 years) and long-term analyses (∼70 years) using orthophotos. The results highlight the complex interactions between human activities, storm events, and natural processes, particularly the role of <em>Posidonia</em> accumulation in shaping beach and dune morphology. Medium-term analysis has offered detailed perspective on recent beach changes, illustrating fluctuations in <em>Posidonia</em> berms related to storm events and correlating shoreline positions with dune evolution. Meanwhile, long-term orthophotos analysis has provided insights into sediment transport dynamics and revealed trend patterns over extended timeframes. This integration of SDS data and aerial imagery leveraged the identification of “hotspot areas” by analysing the relationship between shoreline changes and dune toe retreat.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104933"},"PeriodicalIF":4.5,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-12-31DOI: 10.1016/j.coastaleng.2025.104939
Clemens Krautwald , Constantin Schweiger , Jintian Liu , Christian Windt , David Schürenkamp , Markus Böl , Nils Goseberg
The rapid growth of offshore wind energy, motivated by the demand for sustainable energy solutions and the aim of achieving greenhouse gas neutrality, has led to increased attention to the impact of marine biofouling on substructures such as monopiles and jacket structures. Although the effects of hard biofouling have been studied, soft biofouling remains underexplored. This study investigates flow dynamics and vorticity patterns around eight cylindrical structures subjected to wave loading, with hard and soft biofouling surrogates. Soft biofouling is further divided into stiff and flexible models. Physical experiments are conducted with slender piles () in a mid-scale wave flume, covering Reynolds numbers of and Keulegan–Carpenter numbers of . Volumetric flow velocities are measured using Particle-Tracking Velocimetry with the Shake-the-Box method. Results show that biofouling alters flow patterns, creating recirculation zones with reverse flow velocities. Vorticity analysis reveals vortex formation in the wake, expanding with wave period and roughness. For the same fibre lengths, flexible biofouling models allow high levels of vorticity to spread further downstream (up to 133%), while stiff models create distinctive recirculation zones with a 18% larger recirculation length. These findings improve understanding of wave-induced wake development for rough surfaces.
{"title":"Wave-induced wake dynamics of cylinders with surrogates of marine biofouling","authors":"Clemens Krautwald , Constantin Schweiger , Jintian Liu , Christian Windt , David Schürenkamp , Markus Böl , Nils Goseberg","doi":"10.1016/j.coastaleng.2025.104939","DOIUrl":"10.1016/j.coastaleng.2025.104939","url":null,"abstract":"<div><div>The rapid growth of offshore wind energy, motivated by the demand for sustainable energy solutions and the aim of achieving greenhouse gas neutrality, has led to increased attention to the impact of marine biofouling on substructures such as monopiles and jacket structures. Although the effects of hard biofouling have been studied, soft biofouling remains underexplored. This study investigates flow dynamics and vorticity patterns around eight cylindrical structures subjected to wave loading, with hard and soft biofouling surrogates. Soft biofouling is further divided into stiff and flexible models. Physical experiments are conducted with slender piles (<span><math><mrow><mi>D</mi><mo>/</mo><mi>L</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>07</mn></mrow></math></span>) in a mid-scale wave flume, covering Reynolds numbers of <span><math><mrow><mi>R</mi><mi>e</mi><mo>=</mo><mn>2</mn><mi>⋅</mi><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>4</mn></mrow></msup><mo>−</mo><mn>2</mn><mi>⋅</mi><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>5</mn></mrow></msup></mrow></math></span> and Keulegan–Carpenter numbers of <span><math><mrow><mi>K</mi><mi>C</mi><mo>=</mo><mn>2</mn><mo>−</mo><mn>50</mn></mrow></math></span>. Volumetric flow velocities are measured using Particle-Tracking Velocimetry with the Shake-the-Box method. Results show that biofouling alters flow patterns, creating recirculation zones with reverse flow velocities. Vorticity analysis reveals vortex formation in the wake, expanding with wave period and roughness. For the same fibre lengths, flexible biofouling models allow high levels of vorticity to spread further downstream (up to 133%), while stiff models create distinctive recirculation zones with a 18% larger recirculation length. These findings improve understanding of wave-induced wake development for rough surfaces.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104939"},"PeriodicalIF":4.5,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-11-29DOI: 10.1016/j.coastaleng.2025.104923
John T. Goertz , Nikos Kalligeris , Sunghoon Han , James M. Kaihatu , Patrick J. Lynett , Costas E. Synolakis
Observations of coastal inundation on the western coast of South Pagai Island (Indonesia) in the wake of the 2010 Mentawais tsunami revealed up to 50 % more inundation in areas in the shadow zone of a large island (located 4 km offshore of South Pagai) than in open coastal areas. A series of laboratory tests of long waves impacting islands were conducted to verify this observation. Long waves (both solitary waves and evolving “error function” waves) were generated in a large directional wave basin. Laboratory-scale islands were made from sheet metal in two configurations of two different diameters apiece: a full conical cross-section (representing a volcanic island) and a conical section truncated at the water line (representing a fringing reef). The islands were also located at varying distances from the sloping beach. Video imagery taken from cameras mounted on a tank-spanning bridge was used to quantify the runup in the shadow zone of the island. It is shown that the runup inundation on the beach in the shadow zone of each island is amplified relative to the inundation on portions of the beach not facing an island. Comparisons to existing formulations for solitary wave runup on open coast beaches show increasing deviations from these expressions for cases in which the “effective wavelength” of the solitary wave is smaller than the base diameter of the island. In most cases the runup is greatest when the island is closest to the beach, with the next-highest inundation seen when the island is furthest away. This observation is further buttressed by similar trends in energy characteristics and inundation surface area and may be linked to the greater lateral spread of the long wave disturbance seen in larger island distances.
{"title":"Laboratory observations of long wave inundation of shorelines in the shadow of islands","authors":"John T. Goertz , Nikos Kalligeris , Sunghoon Han , James M. Kaihatu , Patrick J. Lynett , Costas E. Synolakis","doi":"10.1016/j.coastaleng.2025.104923","DOIUrl":"10.1016/j.coastaleng.2025.104923","url":null,"abstract":"<div><div>Observations of coastal inundation on the western coast of South Pagai Island (Indonesia) in the wake of the 2010 Mentawais tsunami revealed up to 50 % more inundation in areas in the shadow zone of a large island (located 4 km offshore of South Pagai) than in open coastal areas. A series of laboratory tests of long waves impacting islands were conducted to verify this observation. Long waves (both solitary waves and evolving “error function” waves) were generated in a large directional wave basin. Laboratory-scale islands were made from sheet metal in two configurations of two different diameters apiece: a full conical cross-section (representing a volcanic island) and a conical section truncated at the water line (representing a fringing reef). The islands were also located at varying distances from the sloping beach. Video imagery taken from cameras mounted on a tank-spanning bridge was used to quantify the runup in the shadow zone of the island. It is shown that the runup inundation on the beach in the shadow zone of each island is amplified relative to the inundation on portions of the beach not facing an island. Comparisons to existing formulations for solitary wave runup on open coast beaches show increasing deviations from these expressions for cases in which the “effective wavelength” of the solitary wave is smaller than the base diameter of the island. In most cases the runup is greatest when the island is closest to the beach, with the next-highest inundation seen when the island is furthest away. This observation is further buttressed by similar trends in energy characteristics and inundation surface area and may be linked to the greater lateral spread of the long wave disturbance seen in larger island distances.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104923"},"PeriodicalIF":4.5,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2026-01-17DOI: 10.1016/j.coastaleng.2026.104949
Junwei Ye, Deping Cao
Flexible structures offer a cost-effective, environmentally friendly, and easily installable solution for coastal protection. This study numerically investigates the interaction between a solitary wave and a submerged vertical elastic plate using a fully coupled computational fluid dynamics (CFD) and computational solid mechanics (CSM) model. Model reliability was confirmed via a mesh convergence study, turbulence model selection and validation against existing experimental and numerical data. The effects of key parameters such as incident wave height, stiffness coefficient, mass coefficient, and Poisson's ratio were systematically examined. Results indicate that the incident wave height governs the degree of nonlinearity in the interaction, while the stiffness coefficient is the key structural parameter: its increase effectively reduces plate displacement and horizontal force but increases wave transmission and reflection coefficients. The mass coefficient exhibits negligible influence within the studied parametric range. Poisson's ratio shows limited sensitivity on wave coefficients but significantly affects structural responses (displacement and horizontal force). Based on the parametric study, a set of empirical formulae was developed to predict the wave transmission coefficient, reflection coefficient, peak horizontal load, and maximum horizontal displacement. These formulae provide a beneficial predictive tool for the design and performance assessment of submerged flexible structures.
{"title":"Numerical investigation of solitary wave interaction with a vertical elastic submerged plate","authors":"Junwei Ye, Deping Cao","doi":"10.1016/j.coastaleng.2026.104949","DOIUrl":"10.1016/j.coastaleng.2026.104949","url":null,"abstract":"<div><div>Flexible structures offer a cost-effective, environmentally friendly, and easily installable solution for coastal protection. This study numerically investigates the interaction between a solitary wave and a submerged vertical elastic plate using a fully coupled computational fluid dynamics (CFD) and computational solid mechanics (CSM) model. Model reliability was confirmed via a mesh convergence study, turbulence model selection and validation against existing experimental and numerical data. The effects of key parameters such as incident wave height, stiffness coefficient, mass coefficient, and Poisson's ratio were systematically examined. Results indicate that the incident wave height governs the degree of nonlinearity in the interaction, while the stiffness coefficient is the key structural parameter: its increase effectively reduces plate displacement and horizontal force but increases wave transmission and reflection coefficients. The mass coefficient exhibits negligible influence within the studied parametric range. Poisson's ratio shows limited sensitivity on wave coefficients but significantly affects structural responses (displacement and horizontal force). Based on the parametric study, a set of empirical formulae was developed to predict the wave transmission coefficient, reflection coefficient, peak horizontal load, and maximum horizontal displacement. These formulae provide a beneficial predictive tool for the design and performance assessment of submerged flexible structures.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104949"},"PeriodicalIF":4.5,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-15Epub Date: 2025-12-20DOI: 10.1016/j.coastaleng.2025.104938
Hassan Akbari, Melika MohammadBeiki
Wave interaction with permeable breakwaters has a direct influence on the stability and hydraulic response of these structures. SPH is a Lagrangian model with the ability to track wave particles within the breakwater layers. Modeling the complex 3D flow among the armors usually requires impractical computational effort. An alternative approach, called quasi-3D, is introduced in this research to approximate the wave penetration patterns through permeable layers. The proposed method is applicable to porous media consisting of large materials with interconnected free spaces. The performance of the proposed method is validated against experimental data, full-3D and 2D macroscopic numerical models. Then, wave run-up over different armor shapes is modeled, and the effects of armor arrangement and the layer's porosity on the results are investigated. In general, comparing the computational costs showed that the proposed model is at least 150 times faster than a full-3D model with the same resolution. Based on the results, it is concluded that overlooking the porosity of armor and underneath layers in numerical models leads to underestimated run-up values. In addition, using a macroscopic approach for modeling armor layer can result in underestimated values because it assumes no surface roughness. However, the macroscopic approach remains a suitable method for modeling the permeability of core layers with fine and wide-graded materials. On the other hand, both roughness and porosity of breakwater layers can be taken into account by the proposed model. Its results demonstrated that the arrangements as well as the shape of armor units have a great influence on the wave propagation pattern, its breaking type, and the forces applied to armor layer. Such information helps designers to estimate the stability of armor blocks accurately with low computational effort, as a function of armor shape and arrangement.
{"title":"A quasi-3D SPH model to simulate wave interaction with permeable breakwaters","authors":"Hassan Akbari, Melika MohammadBeiki","doi":"10.1016/j.coastaleng.2025.104938","DOIUrl":"10.1016/j.coastaleng.2025.104938","url":null,"abstract":"<div><div>Wave interaction with permeable breakwaters has a direct influence on the stability and hydraulic response of these structures. SPH is a Lagrangian model with the ability to track wave particles within the breakwater layers. Modeling the complex 3D flow among the armors usually requires impractical computational effort. An alternative approach, called quasi-3D, is introduced in this research to approximate the wave penetration patterns through permeable layers. The proposed method is applicable to porous media consisting of large materials with interconnected free spaces. The performance of the proposed method is validated against experimental data, full-3D and 2D macroscopic numerical models. Then, wave run-up over different armor shapes is modeled, and the effects of armor arrangement and the layer's porosity on the results are investigated. In general, comparing the computational costs showed that the proposed model is at least 150 times faster than a full-3D model with the same resolution. Based on the results, it is concluded that overlooking the porosity of armor and underneath layers in numerical models leads to underestimated run-up values. In addition, using a macroscopic approach for modeling armor layer can result in underestimated values because it assumes no surface roughness. However, the macroscopic approach remains a suitable method for modeling the permeability of core layers with fine and wide-graded materials. On the other hand, both roughness and porosity of breakwater layers can be taken into account by the proposed model. Its results demonstrated that the arrangements as well as the shape of armor units have a great influence on the wave propagation pattern, its breaking type, and the forces applied to armor layer. Such information helps designers to estimate the stability of armor blocks accurately with low computational effort, as a function of armor shape and arrangement.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104938"},"PeriodicalIF":4.5,"publicationDate":"2026-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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