Pub Date : 2025-11-22DOI: 10.1016/j.apor.2025.104865
Zhu Li , Yujiao Zheng , Suxian Lv , Wude Xie , Lixin Zhu , Lu Wang , Junyang Ma , Chunliu Guo , Yize Zhang , Zhenlin Liang , Zhaoyang Jiang
Artificial reefs (ARs), as one of the important means for restoring marine habitats, largely depend on their structures for hydrodynamic performance. In this study, we combined particle image velocimetry experiment (PIV) and computational fluid dynamics (CFD) to investigate the influence of a grid guide plate structure on the hydrodynamic performance of the cubic-frame reef. The results reveal that the angles of the front guide plates significantly enhance the upwelling efficiency of the cubic-frame reef, with a maximum increase of 13.06 times. The projected area of the plates also has a significant impact on the upwelling flux. Normalized TKE (kn) effectively quantifies wake disturbance intensity and shows a strong correlation with vortex volume. Furthermore, asymmetric plate configurations enhance wake vortex mixing while minimizing energy dissipation. The wake efficiency of the optimized AR structure is 28.31 times greater than that of the cubic-frame reef. These findings demonstrate that optimized guide plate configurations can enhance upwelling efficiency and wake mixing by more than an order of magnitude, providing a practical design basis for constructing artificial reefs that improve water exchange and habitat quality in marine ranching applications.
{"title":"Hydrodynamic performance of artificial reef with guide plates: A combined computational fluid dynamics and particle image velocimetry investigation","authors":"Zhu Li , Yujiao Zheng , Suxian Lv , Wude Xie , Lixin Zhu , Lu Wang , Junyang Ma , Chunliu Guo , Yize Zhang , Zhenlin Liang , Zhaoyang Jiang","doi":"10.1016/j.apor.2025.104865","DOIUrl":"10.1016/j.apor.2025.104865","url":null,"abstract":"<div><div>Artificial reefs (ARs), as one of the important means for restoring marine habitats, largely depend on their structures for hydrodynamic performance. In this study, we combined particle image velocimetry experiment (PIV) and computational fluid dynamics (CFD) to investigate the influence of a grid guide plate structure on the hydrodynamic performance of the cubic-frame reef. The results reveal that the angles of the front guide plates significantly enhance the upwelling efficiency of the cubic-frame reef, with a maximum increase of 13.06 times. The projected area of the plates also has a significant impact on the upwelling flux. Normalized TKE (<em>k<sub>n</sub></em>) effectively quantifies wake disturbance intensity and shows a strong correlation with vortex volume. Furthermore, asymmetric plate configurations enhance wake vortex mixing while minimizing energy dissipation. The wake efficiency of the optimized AR structure is 28.31 times greater than that of the cubic-frame reef. These findings demonstrate that optimized guide plate configurations can enhance upwelling efficiency and wake mixing by more than an order of magnitude, providing a practical design basis for constructing artificial reefs that improve water exchange and habitat quality in marine ranching applications.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104865"},"PeriodicalIF":4.4,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576260","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 : 2025-11-22DOI: 10.1016/j.apor.2025.104868
Giorgia Adami , Riccardo Rocchi , Massimo Figari
The maritime industry faces mounting pressure to reduce its greenhouse gas emissions, with regulatory bodies increasingly targeting decarbonization. While much of this attention has centred on commercial shipping, military fleets continue to operate largely outside the scope of emission regulations, despite their non-negligible environmental footprint. This study investigates the potential of carbon capture technologies as a viable and immediate solution for reducing carbon dioxide emissions from naval vessels, including those employed in military contexts. It examines the current advancements in onboard carbon capture systems and outlines the evolving regulatory landscape and preliminary standards introduced by leading classification societies. Amine-based absorption and calcium looping are selected for detailed analysis through a case study on a modern destroyer. Their implementation is evaluated under realistic operational conditions, focusing on carbon dioxide capture rate, auxiliary power demand, volumetric and mass impact, and integration constraints. The comparative evaluation underscores the trade-offs in technological readiness, effectiveness, and adaptability for maritime use. Ultimately, the research offers valuable insight into the potential role of carbon capture in greening the military maritime sector and advocates for the expansion of decarbonization efforts to encompass naval operations.
{"title":"Exploring carbon capture for maritime decarbonization: A case study on a military vessel","authors":"Giorgia Adami , Riccardo Rocchi , Massimo Figari","doi":"10.1016/j.apor.2025.104868","DOIUrl":"10.1016/j.apor.2025.104868","url":null,"abstract":"<div><div>The maritime industry faces mounting pressure to reduce its greenhouse gas emissions, with regulatory bodies increasingly targeting decarbonization. While much of this attention has centred on commercial shipping, military fleets continue to operate largely outside the scope of emission regulations, despite their non-negligible environmental footprint. This study investigates the potential of carbon capture technologies as a viable and immediate solution for reducing carbon dioxide emissions from naval vessels, including those employed in military contexts. It examines the current advancements in onboard carbon capture systems and outlines the evolving regulatory landscape and preliminary standards introduced by leading classification societies. Amine-based absorption and calcium looping are selected for detailed analysis through a case study on a modern destroyer. Their implementation is evaluated under realistic operational conditions, focusing on carbon dioxide capture rate, auxiliary power demand, volumetric and mass impact, and integration constraints. The comparative evaluation underscores the trade-offs in technological readiness, effectiveness, and adaptability for maritime use. Ultimately, the research offers valuable insight into the potential role of carbon capture in greening the military maritime sector and advocates for the expansion of decarbonization efforts to encompass naval operations.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104868"},"PeriodicalIF":4.4,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576200","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 : 2025-11-21DOI: 10.1016/j.apor.2025.104864
Hamid Ahmadi , Mahdi Ghorbani
The reinforcement of tubular joints in jacket structures, such as the foundations of offshore wind turbines, is a common practice. To establish comprehensive design guidelines for predicting the ultimate strength of two-planar tubular DK-joints reinforced with fiber reinforced polymer (FRP), in the first step, nonlinear finite element (FE) models were developed and verified against experimental data of unreinforced and FRP-reinforced steel tubular Y-joints. The validated FE methodology was then employed to conduct parametric studies. In total, 345 nonlinear FE models were generated and analyzed to investigate the effects of dimensionless geometrical parameters of the joint, the number of FRP layers, the FRP layer orientations, and the FRP sheet length on the static performance of FRP-reinforced two-planar tubular DK-joints. The results of parametric study were utilized to formulate a parametric equation, through nonlinear regression analyses, to predict the ultimate capacity of two-planar tubular DK-connections strengthened with FRP under axial loading. The key findings demonstrated that the FRP reinforcement can significantly enhance the static performance of tubular connections, including improvements in both stiffness and ultimate strength, and the developed parametric equation can be reliably used for the calculation of ultimate strength of FRP-reinforced two-planar tubular DK-joints subjected to axial loading.
{"title":"Static load-bearing capacity of multi-planar tubular DK-joints reinforced with FRP composites in offshore wind turbine foundations","authors":"Hamid Ahmadi , Mahdi Ghorbani","doi":"10.1016/j.apor.2025.104864","DOIUrl":"10.1016/j.apor.2025.104864","url":null,"abstract":"<div><div>The reinforcement of tubular joints in jacket structures, such as the foundations of offshore wind turbines, is a common practice. To establish comprehensive design guidelines for predicting the ultimate strength of two-planar tubular DK-joints reinforced with fiber reinforced polymer (FRP), in the first step, nonlinear finite element (FE) models were developed and verified against experimental data of unreinforced and FRP-reinforced steel tubular Y-joints. The validated FE methodology was then employed to conduct parametric studies. In total, 345 nonlinear FE models were generated and analyzed to investigate the effects of dimensionless geometrical parameters of the joint, the number of FRP layers, the FRP layer orientations, and the FRP sheet length on the static performance of FRP-reinforced two-planar tubular DK-joints. The results of parametric study were utilized to formulate a parametric equation, through nonlinear regression analyses, to predict the ultimate capacity of two-planar tubular DK-connections strengthened with FRP under axial loading. The key findings demonstrated that the FRP reinforcement can significantly enhance the static performance of tubular connections, including improvements in both stiffness and ultimate strength, and the developed parametric equation can be reliably used for the calculation of ultimate strength of FRP-reinforced two-planar tubular DK-joints subjected to axial loading.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104864"},"PeriodicalIF":4.4,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576198","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 : 2025-11-20DOI: 10.1016/j.apor.2025.104863
Giorgio Palma , Andrea Serani , Shawn Aram , David W. Wundrow , David Drazen , Matteo Diez
Digital twins are widely considered enablers of groundbreaking changes in the development, operation, and maintenance of novel generations of products. They are meant to provide reliable and timely predictions to inform decisions along the entire product life cycle. One of the relevant applications in the naval domain is the digital twinning of ship performance in waves, a crucial aspect in operational efficiency and safety. In this paper, a Bayesian extension of the Hankel dynamic mode decomposition is proposed for ship motion nowcasting and compared with its deterministic counterpart. The proposed method meets all the requirements for formulations devoted to digital twinning, being able to adapt the resulting model based on the data from the physical system, using a limited amount of data, producing real-time predictions, and estimating their reliability. Results are presented and discussed for the course-keeping of the 5415M model in beam-quartering sea state 7 irregular waves at Fr = 0.33, using benchmark data from three different CFD solvers, used as a proxy to real vessel operations. The results show reasonably accurate predictions up to five wave encounters, with the Bayesian formulation improving the deterministic forecasts. In addition, a promising relationship between uncertainty and accuracy is found.
{"title":"Bayesian Hankel dynamic mode decomposition for ship motion digital twinning","authors":"Giorgio Palma , Andrea Serani , Shawn Aram , David W. Wundrow , David Drazen , Matteo Diez","doi":"10.1016/j.apor.2025.104863","DOIUrl":"10.1016/j.apor.2025.104863","url":null,"abstract":"<div><div>Digital twins are widely considered enablers of groundbreaking changes in the development, operation, and maintenance of novel generations of products. They are meant to provide reliable and timely predictions to inform decisions along the entire product life cycle. One of the relevant applications in the naval domain is the digital twinning of ship performance in waves, a crucial aspect in operational efficiency and safety. In this paper, a Bayesian extension of the Hankel dynamic mode decomposition is proposed for ship motion nowcasting and compared with its deterministic counterpart. The proposed method meets all the requirements for formulations devoted to digital twinning, being able to adapt the resulting model based on the data from the physical system, using a limited amount of data, producing real-time predictions, and estimating their reliability. Results are presented and discussed for the course-keeping of the 5415M model in beam-quartering sea state 7 irregular waves at Fr = 0.33, using benchmark data from three different CFD solvers, used as a proxy to real vessel operations. The results show reasonably accurate predictions up to five wave encounters, with the Bayesian formulation improving the deterministic forecasts. In addition, a promising relationship between uncertainty and accuracy is found.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104863"},"PeriodicalIF":4.4,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576259","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 : 2025-11-20DOI: 10.1016/j.apor.2025.104871
Wei Chen , Thi Thuy Nga Nguyen , Johannes Pein , Frédéric Jourdin , Ronan Fablet , Joanna Staneva
We introduce an end-to-end deep, physics-informed learning framework, 4DVarNet, for reconstructing high-resolution spatiotemporal fields of suspended particulate matter (SPM) in coastal seas by synergistically combining numerical models and sparse CMEMS observations. The approach employs a novel two-phase transfer learning strategy: (1) pre-training on Observing System Simulation Experiments (OSSEs) where gap-free model outputs are masked with synthetic cloud patterns, and (2) fine-tuning on Observing System Experiments (OSEs) using sparse satellite data and an additional independent validation mask. This design enables the network to transfer the physical dynamics learned from the models to observation-driven reconstructions. The architecture embeds a trainable dynamical prior and a convolutional LSTM solver to iteratively minimize a cost function that balances data agreement with physical consistency. Applied to the German Bight in 2020, the framework demonstrates robust performance under operational conditions, outperforming DInEOF, eDInEOF with a 70% reduction in RMSE and correlations up to . Reconstructions preserve fine-scale spatial patterns while maintaining accuracy, with the structure similarity index increased by 50% compared to the EOF approaches. Half of the errors are within 0.2 mg/L, even when 27% of days lack any observations. Sensitivity experiments reveal that removing available data increases RMSE and smooths fine-scale SPM spatial features. Increasing the assimilation window length degrades data variability. This work establishes that neural networks can successfully bridge model-based and observation-based systems, with immediate applications for coastal monitoring. It also highlights the need to incorporate tidal dynamics and sub-daily variability into future implementations, particularly for applications targeting real-time sediment transport forecasting.
{"title":"Physics-informed neural data assimilation for high-resolution coastal SPM reconstruction from model and satellite data","authors":"Wei Chen , Thi Thuy Nga Nguyen , Johannes Pein , Frédéric Jourdin , Ronan Fablet , Joanna Staneva","doi":"10.1016/j.apor.2025.104871","DOIUrl":"10.1016/j.apor.2025.104871","url":null,"abstract":"<div><div>We introduce an end-to-end deep, physics-informed learning framework, 4DVarNet, for reconstructing high-resolution spatiotemporal fields of suspended particulate matter (SPM) in coastal seas by synergistically combining numerical models and sparse CMEMS observations. The approach employs a novel two-phase transfer learning strategy: (1) pre-training on Observing System Simulation Experiments (OSSEs) where gap-free model outputs are masked with synthetic cloud patterns, and (2) fine-tuning on Observing System Experiments (OSEs) using sparse satellite data and an additional independent validation mask. This design enables the network to transfer the physical dynamics learned from the models to observation-driven reconstructions. The architecture embeds a trainable dynamical prior and a convolutional LSTM solver to iteratively minimize a cost function that balances data agreement with physical consistency. Applied to the German Bight in 2020, the framework demonstrates robust performance under operational conditions, outperforming DInEOF, eDInEOF with a 70% reduction in RMSE and correlations up to <span><math><mrow><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0</mn><mo>.</mo><mn>975</mn></mrow></math></span>. Reconstructions preserve fine-scale spatial patterns while maintaining accuracy, with the structure similarity index increased by 50% compared to the EOF approaches. Half of the errors are within <span><math><mo>±</mo></math></span> 0.2 mg/L, even when 27% of days lack any observations. Sensitivity experiments reveal that removing available data increases RMSE and smooths fine-scale SPM spatial features. Increasing the assimilation window length degrades data variability. This work establishes that neural networks can successfully bridge model-based and observation-based systems, with immediate applications for coastal monitoring. It also highlights the need to incorporate tidal dynamics and sub-daily variability into future implementations, particularly for applications targeting real-time sediment transport forecasting.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104871"},"PeriodicalIF":4.4,"publicationDate":"2025-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576261","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 : 2025-11-19DOI: 10.1016/j.apor.2025.104861
Anupam Das , Tanmoy Konar
Previous research has shown that compliant liquid damper-inerter (CLDI) systems, especially with a negative stiffness (NS) element, effectively reduce vibrations of monopile-supported offshore wind turbine towers (MOWTTs) exposed to multiple hazards, including earthquakes, wind, and waves. These studies assumed the monopile to be fixed at the base. However, in reality, dynamic interaction occurs between the monopile and soil under dynamic loading, which affects the damper system's performance. This study explores the impact of monopile-soil interaction (MSI) on the control effectiveness of a negative stiffness-assisted compliant liquid damper-inerter (NS-CLDI) designed for an MOWTT. The equations of motion are developed for the combined MOWTT-damper system. A 5-MW NREL MOWTT is selected as the case structure for the numerical analysis. Soil parameters are obtained from relevant literature. One hundred earthquake ground motion records, scaled to 0.1 g, and five wind-wave loadings are used to create a multi-hazard scenario. The coupling between the monopile and soil is modelled using distributed springs representing the soil stiffness. Results reveal that MSI increases both displacement and acceleration responses of the uncontrolled tower. During the damper design, the peak seismic responses and root mean square wind-wave responses serve as objective functions (OFs). These OFs are minimized using a genetic algorithm-based multi-objective optimization framework. Two sets of optimal NS-CLDI parameters are identified: one for controlling side-side (SS) vibrations, and another for fore-aft (FA) vibrations. The control effectiveness of NS-CLDI is evaluated considering MSI under multi-hazard conditions in both time and frequency domains. While NS-CLDI can significantly reduce vibrations in both SS and FA directions, neglecting MSI during damper design leads to a serious underestimation of MOWTT responses with NS-CLDI.
{"title":"Effect of monopile-soil interaction on performance of negative stiffness-assisted compliant liquid dampers-inerter designed for offshore wind turbine towers","authors":"Anupam Das , Tanmoy Konar","doi":"10.1016/j.apor.2025.104861","DOIUrl":"10.1016/j.apor.2025.104861","url":null,"abstract":"<div><div>Previous research has shown that compliant liquid damper-inerter (CLDI) systems, especially with a negative stiffness (NS) element, effectively reduce vibrations of monopile-supported offshore wind turbine towers (MOWTTs) exposed to multiple hazards, including earthquakes, wind, and waves. These studies assumed the monopile to be fixed at the base. However, in reality, dynamic interaction occurs between the monopile and soil under dynamic loading, which affects the damper system's performance. This study explores the impact of monopile-soil interaction (MSI) on the control effectiveness of a negative stiffness-assisted compliant liquid damper-inerter (NS-CLDI) designed for an MOWTT. The equations of motion are developed for the combined MOWTT-damper system. A 5-MW NREL MOWTT is selected as the case structure for the numerical analysis. Soil parameters are obtained from relevant literature. One hundred earthquake ground motion records, scaled to 0.1 g, and five wind-wave loadings are used to create a multi-hazard scenario. The coupling between the monopile and soil is modelled using distributed springs representing the soil stiffness. Results reveal that MSI increases both displacement and acceleration responses of the uncontrolled tower. During the damper design, the peak seismic responses and root mean square wind-wave responses serve as objective functions (OFs). These OFs are minimized using a genetic algorithm-based multi-objective optimization framework. Two sets of optimal NS-CLDI parameters are identified: one for controlling side-side (SS) vibrations, and another for fore-aft (FA) vibrations. The control effectiveness of NS-CLDI is evaluated considering MSI under multi-hazard conditions in both time and frequency domains. While NS-CLDI can significantly reduce vibrations in both SS and FA directions, neglecting MSI during damper design leads to a serious underestimation of MOWTT responses with NS-CLDI.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104861"},"PeriodicalIF":4.4,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576196","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 : 2025-11-19DOI: 10.1016/j.apor.2025.104862
Muhammad Moman Shahzad , Muhammad Hassaan Farooq Khan , Daeyong Lee
The worldwide impetus for sustainable energy has catalyzed an expansion in offshore wind farm installations; however, the adaptation of 15 MW turbines to existing jacket foundations introduces novel challenges due to the intricate, non-linear marine load conditions. In this research, comprehensive finite-element analyses were performed to assess two retrofitting strategies under the influence of combined wind, wave, and current forces, evaluated across seven distinct wind-wave orientations and three actual geographic locations (Gunsan, Oido, Buan), in addition to one controlled synthetic environment. The findings reveal that Configuration 2, which integrates optimized bracing and tailored member dimensions, markedly decreases peak stress concentrations by over 50 %, mitigates strain hotspots, and reduces lateral and rotational displacements by nearly 50 % when compared to Configuration 1. These enhancements correspond directly to improved fatigue lifespan and decreased sensitivity to variations in load directions, which are essential for ensuring reliable, low-maintenance operation over extended periods in marine environments. By elucidating how targeted design alterations can modernize original jacket systems for next-generation turbines, this study addresses a critical knowledge deficit and provides actionable insights for engineers involved in the retrofitting of foundations to accommodate increasingly larger offshore wind projects.
{"title":"Analyzing the structural integrity of retrofitted jacket substructures for an offshore wind turbine under nonlinear dynamic loading","authors":"Muhammad Moman Shahzad , Muhammad Hassaan Farooq Khan , Daeyong Lee","doi":"10.1016/j.apor.2025.104862","DOIUrl":"10.1016/j.apor.2025.104862","url":null,"abstract":"<div><div>The worldwide impetus for sustainable energy has catalyzed an expansion in offshore wind farm installations; however, the adaptation of 15 MW turbines to existing jacket foundations introduces novel challenges due to the intricate, non-linear marine load conditions. In this research, comprehensive finite-element analyses were performed to assess two retrofitting strategies under the influence of combined wind, wave, and current forces, evaluated across seven distinct wind-wave orientations and three actual geographic locations (Gunsan, Oido, Buan), in addition to one controlled synthetic environment. The findings reveal that Configuration 2, which integrates optimized bracing and tailored member dimensions, markedly decreases peak stress concentrations by over 50 %, mitigates strain hotspots, and reduces lateral and rotational displacements by nearly 50 % when compared to Configuration 1. These enhancements correspond directly to improved fatigue lifespan and decreased sensitivity to variations in load directions, which are essential for ensuring reliable, low-maintenance operation over extended periods in marine environments. By elucidating how targeted design alterations can modernize original jacket systems for next-generation turbines, this study addresses a critical knowledge deficit and provides actionable insights for engineers involved in the retrofitting of foundations to accommodate increasingly larger offshore wind projects.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104862"},"PeriodicalIF":4.4,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576199","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 : 2025-11-19DOI: 10.1016/j.apor.2025.104857
Feiyang Huang , Yi Pan , Weiqiu Chen , Jianjin He , Xinqiang Wang , Qingtong Cai , Zhaoyang Hu , Aifeng Tao , Jinhai Zheng
A dike-front Wave Dissipation Basin (WDB) is proposed as an engineering measure to reduce wave overtopping discharge over sea dikes. Flume tests are conducted to quantify the overtopping reduction effectiveness of the WDB and to compare it with other engineering measures. The tests are carried out under various wave conditions, water levels, and cross-sectional sea dike configurations. Comparisons are made among the overtopping reduction performances of a Simple Sloped Dike (SSD), a sea dike with a wave dissipation berm, an SSD with WDBs of different lengths, an SSD with a detached breakwater (BW), and an SSD with a Stilling Wave Basin (SWB). Results demonstrate that the application of the WDB leads to significantly lower overtopping discharge across a wide range of relative crest freeboards, including both negative and positive values. Empirical equations are proposed to estimate the overtopping reduction coefficient of the WDB. A comprehensive comparison is made among the functional characteristics of four types of engineering measures, i.e. WDB, berm, BW, and SWB. The findings of this study on the dike-front WDB present a promising approach to enhancing the resilience of sea dikes.
{"title":"Comparative study on wave overtopping reduction performance on a novel dike-front wave dissipation basin and other engineering measures","authors":"Feiyang Huang , Yi Pan , Weiqiu Chen , Jianjin He , Xinqiang Wang , Qingtong Cai , Zhaoyang Hu , Aifeng Tao , Jinhai Zheng","doi":"10.1016/j.apor.2025.104857","DOIUrl":"10.1016/j.apor.2025.104857","url":null,"abstract":"<div><div>A dike-front Wave Dissipation Basin (WDB) is proposed as an engineering measure to reduce wave overtopping discharge over sea dikes. Flume tests are conducted to quantify the overtopping reduction effectiveness of the WDB and to compare it with other engineering measures. The tests are carried out under various wave conditions, water levels, and cross-sectional sea dike configurations. Comparisons are made among the overtopping reduction performances of a Simple Sloped Dike (SSD), a sea dike with a wave dissipation berm, an SSD with WDBs of different lengths, an SSD with a detached breakwater (BW), and an SSD with a Stilling Wave Basin (SWB). Results demonstrate that the application of the WDB leads to significantly lower overtopping discharge across a wide range of relative crest freeboards, including both negative and positive values. Empirical equations are proposed to estimate the overtopping reduction coefficient of the WDB. A comprehensive comparison is made among the functional characteristics of four types of engineering measures, i.e. WDB, berm, BW, and SWB. The findings of this study on the dike-front WDB present a promising approach to enhancing the resilience of sea dikes.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104857"},"PeriodicalIF":4.4,"publicationDate":"2025-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576258","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}
In this paper, a new concept of the floating breakwater with zigzag geometry on the seaside of the floating breakwater body was studied numerically. The hydrodynamic analysis of the zigzag floating breakwater has been investigated using the boundary element method based on the three-dimensional diffraction radiation theory. The zigzag floating breakwater was designed by deforming the seaside wall of the breakwater with three different zigzag angles (60, 90, and 120 degrees). The numerical model was validated against experimental data from a pontoon-type breakwater, demonstrating strong agreement with a root mean square error (RMSE) of 0.093 for the transmission coefficient. The RMSE values for sway, heave, and roll response amplitude operators were 0.28, 0.20, and 0.34, respectively, confirming the reliability of the model. The results revealed that the zigzag geometry significantly increases turbulence within the wave field, disrupting typical wave reflection patterns and enhancing energy dissipation due to the greater upstream surface area of the breakwater compared to conventional straight breakwaters. Notably, the 90° zigzag configuration with a middle heave plate exhibited superior performance, achieving a transmission coefficient of 0.28 at w²B/2g = 0.8, compared to 0.84 for a conventional rectangular breakwater. At higher frequencies (w²B/2g ≥ 1.1), the 90° zigzag breakwater with a heave plate further outperformed other designs, achieving a Ct of 0.15 at w²B/2 g = 1.43, compared to 0.44 for the rectangular breakwater. The inclusion of the heave plate was found to enhance performance for mid-range wave conditions but had minimal impact during longer wave periods. For shorter wave periods, the zigzag design demonstrated significant advantages over traditional configurations, particularly in reducing wave transmission.
{"title":"Numerical analysis to consider effect of zigzag floating breakwater geometry on its performance","authors":"Seyed Mohammadreza Tabatabaee Fard , Mohammad Javad Ketabdari , Hamid Reza Ghafari","doi":"10.1016/j.apor.2025.104855","DOIUrl":"10.1016/j.apor.2025.104855","url":null,"abstract":"<div><div>In this paper, a new concept of the floating breakwater with zigzag geometry on the seaside of the floating breakwater body was studied numerically. The hydrodynamic analysis of the zigzag floating breakwater has been investigated using the boundary element method based on the three-dimensional diffraction radiation theory. The zigzag floating breakwater was designed by deforming the seaside wall of the breakwater with three different zigzag angles (60, 90, and 120 degrees). The numerical model was validated against experimental data from a pontoon-type breakwater, demonstrating strong agreement with a root mean square error (RMSE) of 0.093 for the transmission coefficient. The RMSE values for sway, heave, and roll response amplitude operators were 0.28, 0.20, and 0.34, respectively, confirming the reliability of the model. The results revealed that the zigzag geometry significantly increases turbulence within the wave field, disrupting typical wave reflection patterns and enhancing energy dissipation due to the greater upstream surface area of the breakwater compared to conventional straight breakwaters. Notably, the 90° zigzag configuration with a middle heave plate exhibited superior performance, achieving a transmission coefficient of 0.28 at w²B/2g = 0.8, compared to 0.84 for a conventional rectangular breakwater. At higher frequencies (w²B/2<em>g</em> ≥ 1.1), the 90° zigzag breakwater with a heave plate further outperformed other designs, achieving a Ct of 0.15 at w²B/2 <em>g</em> = 1.43, compared to 0.44 for the rectangular breakwater. The inclusion of the heave plate was found to enhance performance for mid-range wave conditions but had minimal impact during longer wave periods. For shorter wave periods, the zigzag design demonstrated significant advantages over traditional configurations, particularly in reducing wave transmission.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104855"},"PeriodicalIF":4.4,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576197","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 : 2025-11-14DOI: 10.1016/j.apor.2025.104856
Zohreh Mousavi , Ru-Ming Feng , Mohammadreza Farhadi , Mir Mohammad Ettefagh , Meysam Bayat , Sina Varahram , Wei-Qiang Feng
Offshore structures, such as monopile Offshore Wind Turbines (OWTs), are subjected to various dynamic loads including waves, wind, and operational vibrations, which can lead to different types of damage. A key consideration in Structural Health Monitoring (SHM) for offshore structures is how soil-structure interaction influences vibration-based damage detection systems. Extracting features manually from vibration signals is often complex, time-consuming, highlighting the need for automatic methods that can learn relevant features straight from raw data. This paper presents a novel vibration-based method for automatic feature learning and damage detection in offshore structures, taking soil interaction into account. A combined deep Convolutional Neural Network and Long Short-Term Memory (CNN-LSTM) network is developed to extract the relevant features from vibration signals reconstructed using the Variational Mode Decomposition (VMD) technique. Integrating the LSTM network with the CNN enhances the detection accuracy and stability while reducing the oscillation. Notably, the proposed method applies VMD-reconstructed vibration signals directly to the deep CNN-LSTM network without requiring separate feature extraction or selection. The VMD technique removes irrelevant components of the vibration signals that do not pertain to the structure’s nature, thereby refining the signals for a more accurate representation of the structure’s condition. The suggested method is verified utilizing experimental data from a lab-scale monopile offshore model that incorporates soil interaction. Vibration data were collected using various accelerometer sensors across different states, including one healthy state and eight damaged states. The results demonstrate that the proposed method effectively learns features from reconstructed vibration data and outperforms comparative methods, making it a promising approach for SHM system development in offshore structures.
{"title":"Enhanced vibration-based damage detection for monopile offshore structures considering soil interaction based on VMD and deep CNN-LSTM","authors":"Zohreh Mousavi , Ru-Ming Feng , Mohammadreza Farhadi , Mir Mohammad Ettefagh , Meysam Bayat , Sina Varahram , Wei-Qiang Feng","doi":"10.1016/j.apor.2025.104856","DOIUrl":"10.1016/j.apor.2025.104856","url":null,"abstract":"<div><div>Offshore structures, such as monopile Offshore Wind Turbines (OWTs), are subjected to various dynamic loads including waves, wind, and operational vibrations, which can lead to different types of damage. A key consideration in Structural Health Monitoring (SHM) for offshore structures is how soil-structure interaction influences vibration-based damage detection systems. Extracting features manually from vibration signals is often complex, time-consuming, highlighting the need for automatic methods that can learn relevant features straight from raw data. This paper presents a novel vibration-based method for automatic feature learning and damage detection in offshore structures, taking soil interaction into account. A combined deep Convolutional Neural Network and Long Short-Term Memory (CNN-LSTM) network is developed to extract the relevant features from vibration signals reconstructed using the Variational Mode Decomposition (VMD) technique. Integrating the LSTM network with the CNN enhances the detection accuracy and stability while reducing the oscillation. Notably, the proposed method applies VMD-reconstructed vibration signals directly to the deep CNN-LSTM network without requiring separate feature extraction or selection. The VMD technique removes irrelevant components of the vibration signals that do not pertain to the structure’s nature, thereby refining the signals for a more accurate representation of the structure’s condition. The suggested method is verified utilizing experimental data from a lab-scale monopile offshore model that incorporates soil interaction. Vibration data were collected using various accelerometer sensors across different states, including one healthy state and eight damaged states. The results demonstrate that the proposed method effectively learns features from reconstructed vibration data and outperforms comparative methods, making it a promising approach for SHM system development in offshore structures.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104856"},"PeriodicalIF":4.4,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526201","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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