Pub 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":"2025-12-31","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 : 2025-12-29DOI: 10.1016/j.coastaleng.2025.104935
Liangyi Yue, Yuzhu Pearl Li
The buoyancy production term has been recognized as essential in turbulence closure models to address the persistent overestimation of turbulence near the air–water interface in Reynolds-averaged Navier–Stokes (RANS) simulations of breaking waves. While generally effective, two-equation – based turbulence models typically use a simple representation of the buoyancy-production term with a constant closure coefficient in the turbulent kinetic energy equation. This can cause turbulence levels to collapse near the interface, essentially to zero within numerical accuracy, resulting in a loss of coupling between the two turbulence model equations. Such a breakdown inhibits the accurate initiation and evolution of turbulence, particularly during wave breaking onset. In this study, we address the decoupling problem by introducing a variable, turbulence-Reynolds-number-based closure coefficient for the buoyancy-production term. This adaptive formulation directly relates the strength of buoyancy production to local turbulence levels. For simulating spilling breaking waves, period-averaged surface elevation profiles show better agreement with experimental measurements. Wave-to-wave variability analysis further highlights the stabilizing effect of the proposed formulation. The notably improved undertow predictions support the use of this variable-coefficient approach in future RANS simulations of surface waves.
{"title":"On the buoyancy production term for Reynolds-averaged modelling of breaking waves","authors":"Liangyi Yue, Yuzhu Pearl Li","doi":"10.1016/j.coastaleng.2025.104935","DOIUrl":"10.1016/j.coastaleng.2025.104935","url":null,"abstract":"<div><div>The buoyancy production term has been recognized as essential in turbulence closure models to address the persistent overestimation of turbulence near the air–water interface in Reynolds-averaged Navier–Stokes (RANS) simulations of breaking waves. While generally effective, two-equation <span><math><mi>k</mi></math></span>–<span><math><mi>ω</mi></math></span> based turbulence models typically use a simple representation of the buoyancy-production term with a constant closure coefficient in the turbulent kinetic energy equation. This can cause turbulence levels to collapse near the interface, essentially to zero within numerical accuracy, resulting in a loss of coupling between the two turbulence model equations. Such a breakdown inhibits the accurate initiation and evolution of turbulence, particularly during wave breaking onset. In this study, we address the decoupling problem by introducing a variable, turbulence-Reynolds-number-based closure coefficient for the buoyancy-production term. This adaptive formulation directly relates the strength of buoyancy production to local turbulence levels. For simulating spilling breaking waves, period-averaged surface elevation profiles show better agreement with experimental measurements. Wave-to-wave variability analysis further highlights the stabilizing effect of the proposed formulation. The notably improved undertow predictions support the use of this variable-coefficient approach in future RANS simulations of surface waves.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104935"},"PeriodicalIF":4.5,"publicationDate":"2025-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145883954","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 : 2025-12-27DOI: 10.1016/j.coastaleng.2025.104944
Nobuki Fukui , Nobuhito Mori , Sooyoul Kim , Yuto Okajima , Tomoya Shimura , Takuya Miyashita
The applicability of current subgrid models, particularly drag force models (DFMs), for the simulation of large-scale storm surge inundation in highly urbanized coastal megacities remains unclear, particularly in terms of their performance across varying grid resolutions and their ability to capture complex inundation dynamics at the city scale. This paper proposes an enhanced subgrid model, iDFM-MD, for storm surge inundation over a coastal city, incorporating both building drag and volume effects using a wet fraction formulation based on the authors’ previous subgrid model, iDFM. The proposed model was applied to the numerical modeling of storm surge inundation targeting a large coastal city along Tokyo Bay in a pseudo-global warming scenario involving Typhoon Hagibis (2019). The obtained results were compared with a high-resolution structure-resolving model: iDFM-MD produced better estimates of the inundation starting time, depth, and extent, attributed to the consideration of building volumes. The model could reduce the mean absolute error in the water depth to 0.27 m and improve building-scale inundation classification. A sensitivity analysis of the inundation characteristics helped confirm that the model could maintain its accuracy at resolutions of up to 60 m. Our findings demonstrate the capability of iDFM-MD in providing efficient and accurate predictions of urban inundation under future climatic conditions.
{"title":"Subgrid modeling of storm surge inundation in a large coastal city considering building volumes","authors":"Nobuki Fukui , Nobuhito Mori , Sooyoul Kim , Yuto Okajima , Tomoya Shimura , Takuya Miyashita","doi":"10.1016/j.coastaleng.2025.104944","DOIUrl":"10.1016/j.coastaleng.2025.104944","url":null,"abstract":"<div><div>The applicability of current subgrid models, particularly drag force models (DFMs), for the simulation of large-scale storm surge inundation in highly urbanized coastal megacities remains unclear, particularly in terms of their performance across varying grid resolutions and their ability to capture complex inundation dynamics at the city scale. This paper proposes an enhanced subgrid model, iDFM-MD, for storm surge inundation over a coastal city, incorporating both building drag and volume effects using a wet fraction formulation based on the authors’ previous subgrid model, iDFM. The proposed model was applied to the numerical modeling of storm surge inundation targeting a large coastal city along Tokyo Bay in a pseudo-global warming scenario involving Typhoon Hagibis (2019). The obtained results were compared with a high-resolution structure-resolving model: iDFM-MD produced better estimates of the inundation starting time, depth, and extent, attributed to the consideration of building volumes. The model could reduce the mean absolute error in the water depth to 0.27 m and improve building-scale inundation classification. A sensitivity analysis of the inundation characteristics helped confirm that the model could maintain its accuracy at resolutions of up to 60 m. Our findings demonstrate the capability of iDFM-MD in providing efficient and accurate predictions of urban inundation under future climatic conditions.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104944"},"PeriodicalIF":4.5,"publicationDate":"2025-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145883953","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 : 2025-12-26DOI: 10.1016/j.coastaleng.2025.104943
Lili Qu , Scott Draper , Hongwei An , Phil Watson
Squat, shallowly embedded subsea structures are widely used in offshore engineering as foundations to support other structures, but they are particularly vulnerable to local scour and undermining due to their geometric characteristics. This study investigates the effectiveness of various design modifications and protection strategies in mitigating scour around such structures under live-bed flow conditions. A comprehensive experimental program was conducted to examine the influence of corner geometry, skirt depth, skirt configuration, and protective countermeasures including rock berms and concrete mattresses. Results show that rounding corners reduces equilibrium scour depth more than 20 %, while deeper skirts delay undermining but may increase scour due to increased flow blockage. Among the tested designs, a configuration with only an inner skirt achieved the greatest scour reduction, by balancing reduced blockage with undermining resistance. Both reactive (post-scour rock dumping) and proactive (pre-installed protection layers) approaches proved effective, with pre-installed systems offering better long-term stability. These findings provide practical insights into scour control for squat offshore foundations, informing both design optimization and protection planning in erosive marine environments.
{"title":"Scour mitigation for squat, shallowly embedded structures","authors":"Lili Qu , Scott Draper , Hongwei An , Phil Watson","doi":"10.1016/j.coastaleng.2025.104943","DOIUrl":"10.1016/j.coastaleng.2025.104943","url":null,"abstract":"<div><div>Squat, shallowly embedded subsea structures are widely used in offshore engineering as foundations to support other structures, but they are particularly vulnerable to local scour and undermining due to their geometric characteristics. This study investigates the effectiveness of various design modifications and protection strategies in mitigating scour around such structures under live-bed flow conditions. A comprehensive experimental program was conducted to examine the influence of corner geometry, skirt depth, skirt configuration, and protective countermeasures including rock berms and concrete mattresses. Results show that rounding corners reduces equilibrium scour depth more than 20 %, while deeper skirts delay undermining but may increase scour due to increased flow blockage. Among the tested designs, a configuration with only an inner skirt achieved the greatest scour reduction, by balancing reduced blockage with undermining resistance. Both reactive (post-scour rock dumping) and proactive (pre-installed protection layers) approaches proved effective, with pre-installed systems offering better long-term stability. These findings provide practical insights into scour control for squat offshore foundations, informing both design optimization and protection planning in erosive marine environments.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104943"},"PeriodicalIF":4.5,"publicationDate":"2025-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884571","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 : 2025-12-23DOI: 10.1016/j.coastaleng.2025.104942
Ziyan Zhang , Xiaoming Xia , Bing Liu , Tinglu Cai , Huidi Liang , Yining Chen
Small-scale groyne systems in macrotidal environments can stabilize tidal flats. However, their stabilizing performance and functional limits remain poorly quantified. This study investigates a small-scale groyne system in Hangzhou Bay through a 2.5 year monitoring program combining high-frequency Surface Elevation Table (SET) measurements, broad-scale UAV-LiDAR surveys, and sediment dynamic observations. Field observations were subsequently integrated into the SAE-RR framework to enable a systematic assessment of groyne performance. At the site scale, Relative Reduction (RR) metrics reveal that the groyne consistently dampens natural morphodynamics with mean RR values of −0.38 on the sheltered side and −0.14 on the exposed side, and an influence extending approximately five groyne lengths downstream. At the local scale, the Sheltering Asymmetry Efficiency (SAE) metric, derived from SET data, quantifies this effect's strong asymmetry: the groyne suppresses erosion by up to 61 % and reduces accretion by 59 % on its sheltered side compared to the exposed side. Sediment dynamic observations further reveal the underlying mechanism for the damping effect that the groyne creates a gradient in sediment transport capacity by attenuating flow velocity and turbulent kinetic energy. This damping function has an operational limit, diminishing in effectiveness when background variation exceeds ∼0.58 m. These results suggest small-scale groynes as state-dependent morphodynamic dampers whilst SAE-RR as a process-based diagnostic framework for quantifying damping function, thereby providing quantitative constraints essential for implementing adaptive coastal engineering design and management.
{"title":"Small-scale groynes as morphodynamic damper in a macrotidal estuary: A SAE-RR assessment framework","authors":"Ziyan Zhang , Xiaoming Xia , Bing Liu , Tinglu Cai , Huidi Liang , Yining Chen","doi":"10.1016/j.coastaleng.2025.104942","DOIUrl":"10.1016/j.coastaleng.2025.104942","url":null,"abstract":"<div><div>Small-scale groyne systems in macrotidal environments can stabilize tidal flats. However, their stabilizing performance and functional limits remain poorly quantified. This study investigates a small-scale groyne system in Hangzhou Bay through a 2.5 year monitoring program combining high-frequency Surface Elevation Table (SET) measurements, broad-scale UAV-LiDAR surveys, and sediment dynamic observations. Field observations were subsequently integrated into the SAE-RR framework to enable a systematic assessment of groyne performance. At the site scale, Relative Reduction (RR) metrics reveal that the groyne consistently dampens natural morphodynamics with mean RR values of −0.38 on the sheltered side and −0.14 on the exposed side, and an influence extending approximately five groyne lengths downstream. At the local scale, the Sheltering Asymmetry Efficiency (SAE) metric, derived from SET data, quantifies this effect's strong asymmetry: the groyne suppresses erosion by up to 61 % and reduces accretion by 59 % on its sheltered side compared to the exposed side. Sediment dynamic observations further reveal the underlying mechanism for the damping effect that the groyne creates a gradient in sediment transport capacity by attenuating flow velocity and turbulent kinetic energy. This damping function has an operational limit, diminishing in effectiveness when background variation exceeds ∼0.58 m. These results suggest small-scale groynes as state-dependent morphodynamic dampers whilst SAE-RR as a process-based diagnostic framework for quantifying damping function, thereby providing quantitative constraints essential for implementing adaptive coastal engineering design and management.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104942"},"PeriodicalIF":4.5,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840095","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 : 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":"2025-12-20","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}
The flexible cables are prone to scour-induced damage, posing risks to the safe operation of underwater structures. To investigate these impacts, this study carries out three-dimensional laboratory experiments on local scour around a flexible cable. In the experiments, the flow is unidirectional, and only clear-water scour is considered under a constant water depth of 0.45m. By varying the flow intensity (0.7, 0.8, and 0.9), flow incident angle (α = 60°, 75°, 90°), and cable diameter (D = 5 cm and 6 cm), the paper systematically investigates the mechanisms of the local scour, cable motion, strain, lateral scour development velocity, and quasi-equilibrium scour state.
Due to the flexible nature of the cable, its motion differs from that of a rigid pipeline. There is a significant sagging during the scour process, which is quantified by the vertical displacement of the cable. Cable vibration is also observed, which is closely related to its natural frequency and varying test conditions. The deflection of the cable depends on the cable flexibility, test parameters, and the scour process. The result shows that the strain profile along the cable length typically exhibits a parabolic distribution. A point of discontinuity can be observed in the strain time-history curve, which signifies the completion of the lateral expansion of the span shoulder. Visual observations in the texts are consistent with mechanisms previously reported for seepage-induced pipeline-scour initiation, further supporting the applicability of this mechanism for flexible cable. An asymmetric scour pattern is prominent when the flow is oblique to the cable. A large incident angle leads to a more pronounced speed difference between the lateral scour development in two directions. Higher flow intensity results in an increased scour rate and deeper scour depth, as compared to lower flow conditions. As expected, a larger cable diameter yields a larger scour depth.
{"title":"Experimental study on the local scour around flexible submarine cables exposed to three-dimensional current loading","authors":"Fangyu Wang , Jisheng Zhang , Dongfang Liang , Yee-Meng Chiew , Yakun Guo","doi":"10.1016/j.coastaleng.2025.104940","DOIUrl":"10.1016/j.coastaleng.2025.104940","url":null,"abstract":"<div><div>The flexible cables are prone to scour-induced damage, posing risks to the safe operation of underwater structures. To investigate these impacts, this study carries out three-dimensional laboratory experiments on local scour around a flexible cable. In the experiments, the flow is unidirectional, and only clear-water scour is considered under a constant water depth of 0.45m. By varying the flow intensity (0.7, 0.8, and 0.9), flow incident angle (<em>α</em> = 60°, 75°, 90°), and cable diameter (<em>D</em> = 5 cm and 6 cm), the paper systematically investigates the mechanisms of the local scour, cable motion, strain, lateral scour development velocity, and quasi-equilibrium scour state.</div><div>Due to the flexible nature of the cable, its motion differs from that of a rigid pipeline. There is a significant sagging during the scour process, which is quantified by the vertical displacement of the cable. Cable vibration is also observed, which is closely related to its natural frequency and varying test conditions. The deflection of the cable depends on the cable flexibility, test parameters, and the scour process. The result shows that the strain profile along the cable length typically exhibits a parabolic distribution. A point of discontinuity can be observed in the strain time-history curve, which signifies the completion of the lateral expansion of the span shoulder. Visual observations in the texts are consistent with mechanisms previously reported for seepage-induced pipeline-scour initiation, further supporting the applicability of this mechanism for flexible cable. An asymmetric scour pattern is prominent when the flow is oblique to the cable. A large incident angle leads to a more pronounced speed difference between the lateral scour development in two directions. Higher flow intensity results in an increased scour rate and deeper scour depth, as compared to lower flow conditions. As expected, a larger cable diameter yields a larger scour depth.</div></div>","PeriodicalId":50996,"journal":{"name":"Coastal Engineering","volume":"205 ","pages":"Article 104940"},"PeriodicalIF":4.5,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840094","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 : 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":"2025-12-17","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}
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