Pub Date : 2025-12-11DOI: 10.1016/j.apor.2025.104892
Benjamin Krull , Kasper Bilde , Christian Kringel , Richard Meller , Victor Molbak , Georgios Papaioannou , Fabian Schlegel , Matej Tekavčič , Filotas Tziaros
Air lubrication can reduce the frictional resistance of ships, leading to significant fuel cost savings. However, the performance of air lubrication systems varies considerably, depending on the operating conditions. Complex gas morphologies play a crucial role here but are difficult to predict. Such a variety of morphologies (bubbly flow, air layers, or mixed regimes) requires morphology-adaptive methods, such as MultiMorph. This method allows for multiple morphologies of a given phase, including the transfer between them. The injection of gas can result in air bubbles, air layers, or a mixed regime, based on local transfer mechanisms. The ability to predict these morphologies is a distinctive feature of this method. Alternative methods prescribe a specific regime a priori, and do not allow a transition. To assess the suitability of MultiMorph for air lubrication problems, two geometries with different complexities are considered. The first test validates the method against flat plate experiments. Various water velocity and gas flow rate combinations were considered to investigate their influence on gas morphology and the associated drag reduction. The second case features a three-dimensional ship hull geometry with two bubble injectors to test the applicability of the method to a more complex scenario, including a curved geometry. The method performs well in both test cases and qualifies as a useful tool for numerical investigations of air lubrication phenomena.
{"title":"Numerical modelling of air-induced drag reduction allowing the transition between bubbly, air layer and mixed regimes","authors":"Benjamin Krull , Kasper Bilde , Christian Kringel , Richard Meller , Victor Molbak , Georgios Papaioannou , Fabian Schlegel , Matej Tekavčič , Filotas Tziaros","doi":"10.1016/j.apor.2025.104892","DOIUrl":"10.1016/j.apor.2025.104892","url":null,"abstract":"<div><div>Air lubrication can reduce the frictional resistance of ships, leading to significant fuel cost savings. However, the performance of air lubrication systems varies considerably, depending on the operating conditions. Complex gas morphologies play a crucial role here but are difficult to predict. Such a variety of morphologies (bubbly flow, air layers, or mixed regimes) requires morphology-adaptive methods, such as MultiMorph. This method allows for multiple morphologies of a given phase, including the transfer between them. The injection of gas can result in air bubbles, air layers, or a mixed regime, based on local transfer mechanisms. The ability to predict these morphologies is a distinctive feature of this method. Alternative methods prescribe a specific regime <em>a priori</em>, and do not allow a transition. To assess the suitability of MultiMorph for air lubrication problems, two geometries with different complexities are considered. The first test validates the method against flat plate experiments. Various water velocity and gas flow rate combinations were considered to investigate their influence on gas morphology and the associated drag reduction. The second case features a three-dimensional ship hull geometry with two bubble injectors to test the applicability of the method to a more complex scenario, including a curved geometry. The method performs well in both test cases and qualifies as a useful tool for numerical investigations of air lubrication phenomena.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104892"},"PeriodicalIF":4.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734800","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 : 2025-12-09DOI: 10.1016/j.apor.2025.104866
Yongsheng Li , Changli Yu , Weibo Wang , Xu Jiang , Xinlong Zuo , Hongyun Li
The catastrophic failure of thick composite cylindrical pressure hulls under high external hydrostatic pressure was investigated by analytical, numerical and experimental methods. Buckling failure and material failure were both considered to identify which failure mode of such thick hulls initiates first. An elastic buckling analytical model for thick composite cylinders based on Sander theory principles was applied to derive the critical buckling load. Meanwhile, a progressive damage model (PDM) was developed to simulate the material behavior in the region between the first-ply failure and ultimate failure, and the effects of failure criteria and geometrical defects on the implosion load of the test model were investigated. Then ultimate strength were obtained by comprehensive analysis of buckling failure and material failure via analytical and numerical methods. A group of two thick T700 carbon fiber/epoxy composite cylindrical pressure hulls were designed and manufactured, hydrostatic pressure tests were conducted to derive the catastrophic failure characteristics of thick composite pressure hulls and to validate the analytical and numerical results and methodology for the failure analysis of thick composite cylindrical pressure hulls.
{"title":"The catastrophic failure of thick composite cylindrical pressure hulls: Analytical, numerical and experimental investigations","authors":"Yongsheng Li , Changli Yu , Weibo Wang , Xu Jiang , Xinlong Zuo , Hongyun Li","doi":"10.1016/j.apor.2025.104866","DOIUrl":"10.1016/j.apor.2025.104866","url":null,"abstract":"<div><div>The catastrophic failure of thick composite cylindrical pressure hulls under high external hydrostatic pressure was investigated by analytical, numerical and experimental methods. Buckling failure and material failure were both considered to identify which failure mode of such thick hulls initiates first. An elastic buckling analytical model for thick composite cylinders based on Sander theory principles was applied to derive the critical buckling load. Meanwhile, a progressive damage model (PDM) was developed to simulate the material behavior in the region between the first-ply failure and ultimate failure, and the effects of failure criteria and geometrical defects on the implosion load of the test model were investigated. Then ultimate strength were obtained by comprehensive analysis of buckling failure and material failure via analytical and numerical methods. A group of two thick T700 carbon fiber/epoxy composite cylindrical pressure hulls were designed and manufactured, hydrostatic pressure tests were conducted to derive the catastrophic failure characteristics of thick composite pressure hulls and to validate the analytical and numerical results and methodology for the failure analysis of thick composite cylindrical pressure hulls.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104866"},"PeriodicalIF":4.4,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734801","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 : 2025-12-09DOI: 10.1016/j.apor.2025.104878
Iman Aghajanzadeh , Nima Khodadadi , Prannoy Suraneni , Antonio Nanni
Freshwater scarcity remains a major global concern, particularly in coastal regions. Utilizing seawater for concrete production offers a sustainable approach to conserve freshwater resources while supporting construction in marine environments. This study conducts a systematic and data-driven review of seawater-mixed concrete research using the Scopus database, focusing on durability aspects. The analysis reveals that seawater accelerates the early hydration of ordinary Portland cement (OPC) due to the ionic activity of Cl⁻, Na⁺, and Mg²⁺, leading to a denser early-age microstructure and enhanced initial strength. However, long-term strength and durability outcomes remain inconsistent across studies, influenced by curing conditions, ionic composition, and mixture design. Seawater-mixed concrete generally exhibits improved sulfate resistance but shows variable carbonation behavior and increased susceptibility to alkali–silica reaction (ASR), shrinkage, and freeze–thaw damage. The incorporation of supplementary cementitious materials (SCMs) such as metakaolin (MK), fly ash (FA), and ground granulated blast-furnace slag (GGBS) enhances chloride binding and refines the microstructure, mitigating some adverse effects. Overall, this review identifies key research gaps in long-term durability and emphasizes the need for standardized methodologies and data-driven investigations to optimize seawater-mixed concrete for sustainable coastal and marine infrastructure.
{"title":"Seawater-mixed concrete – A review with focus on durability properties","authors":"Iman Aghajanzadeh , Nima Khodadadi , Prannoy Suraneni , Antonio Nanni","doi":"10.1016/j.apor.2025.104878","DOIUrl":"10.1016/j.apor.2025.104878","url":null,"abstract":"<div><div>Freshwater scarcity remains a major global concern, particularly in coastal regions. Utilizing seawater for concrete production offers a sustainable approach to conserve freshwater resources while supporting construction in marine environments. This study conducts a systematic and data-driven review of seawater-mixed concrete research using the Scopus database, focusing on durability aspects. The analysis reveals that seawater accelerates the early hydration of ordinary Portland cement (OPC) due to the ionic activity of Cl⁻, Na⁺, and Mg²⁺, leading to a denser early-age microstructure and enhanced initial strength. However, long-term strength and durability outcomes remain inconsistent across studies, influenced by curing conditions, ionic composition, and mixture design. Seawater-mixed concrete generally exhibits improved sulfate resistance but shows variable carbonation behavior and increased susceptibility to alkali–silica reaction (ASR), shrinkage, and freeze–thaw damage. The incorporation of supplementary cementitious materials (SCMs) such as metakaolin (MK), fly ash (FA), and ground granulated blast-furnace slag (GGBS) enhances chloride binding and refines the microstructure, mitigating some adverse effects. Overall, this review identifies key research gaps in long-term durability and emphasizes the need for standardized methodologies and data-driven investigations to optimize seawater-mixed concrete for sustainable coastal and marine infrastructure.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104878"},"PeriodicalIF":4.4,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734799","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 : 2025-12-09DOI: 10.1016/j.apor.2025.104880
Zhongliang Meng , Yi Ding , Yanjun Liu , Wahyu Rahmaniar , Zijian Li , Ammar Ahmed
To tackle the challenge of low power generation efficiency of wave energy converters in short-period, low-wave-height sea conditions, this study innovatively proposes a dual-impact horizontal rotor wave energy converter (DHRWEC) system. The system employs a horizontal rotor, designed based on involute principles, as its core component to efficiently capture wave energy through co-rotational motion. The VOF method was employed, and wave types were selected based on wave numerical theory. The Realizableturbulence model was selected to establish a numerical wave tank. In the numerical wave tank, the variations in rotor speed and torque for different blade counts were studied, revealing that a blade count of 22 yielded relatively optimal rotor speed and torque, preliminarily determining 22 as the blade count. A physical model was constructed, and wave flume experiments were conducted under short-period, low-wave-height conditions. Experiments show that rotor speed is a critical factor affecting energy conversion efficiency during stable operation, particularly excelling under short wave periods (1.9 s) and low wave heights (0.10 to 0.14 m). An engineering prototype was manufactured, and sea trial experiments were conducted. Sea trial results show that the DHRWEC system achieved a power generation efficiency of 21.33 % under test conditions, significantly outperforming conventional devices. Numerical simulations and experiments collectively validate its superior energy conversion performance.
{"title":"A high-efficiency dual-impact horizontal rotor wave energy converter: Design, analysis, and experimental tests","authors":"Zhongliang Meng , Yi Ding , Yanjun Liu , Wahyu Rahmaniar , Zijian Li , Ammar Ahmed","doi":"10.1016/j.apor.2025.104880","DOIUrl":"10.1016/j.apor.2025.104880","url":null,"abstract":"<div><div>To tackle the challenge of low power generation efficiency of wave energy converters in short-period, low-wave-height sea conditions, this study innovatively proposes a dual-impact horizontal rotor wave energy converter (DHRWEC) system. The system employs a horizontal rotor, designed based on involute principles, as its core component to efficiently capture wave energy through co-rotational motion. The VOF method was employed, and wave types were selected based on wave numerical theory. The Realizable<span><math><mrow><mi>k</mi><mo>−</mo><mrow><mi>ε</mi></mrow></mrow></math></span>turbulence model was selected to establish a numerical wave tank. In the numerical wave tank, the variations in rotor speed and torque for different blade counts were studied, revealing that a blade count of 22 yielded relatively optimal rotor speed and torque, preliminarily determining 22 as the blade count. A physical model was constructed, and wave flume experiments were conducted under short-period, low-wave-height conditions. Experiments show that rotor speed is a critical factor affecting energy conversion efficiency during stable operation, particularly excelling under short wave periods (1.9 s) and low wave heights (0.10 to 0.14 m). An engineering prototype was manufactured, and sea trial experiments were conducted. Sea trial results show that the DHRWEC system achieved a power generation efficiency of 21.33 % under test conditions, significantly outperforming conventional devices. Numerical simulations and experiments collectively validate its superior energy conversion performance.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104880"},"PeriodicalIF":4.4,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734796","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 : 2025-12-08DOI: 10.1016/j.apor.2025.104891
Alfonso M. Gañán-Calvo , Miguel A. Herrada , José M. López-Herrera
The size distribution of sub-micron sea spray aerosols (SSA) is a critical component of climate models, yet the primary physical mechanism governing their production – specifically the competition between film and jet droplets from bubble bursting – has remained a subject of intense debate. This work presents a revised, first-principles model to quantitatively resolve this controversy and demonstrate the dominance of jetting for producing micron and sub-micron aerosols. Our approach first rules out the film droplet mechanism as a primary contributor for this size range by demonstrating through physical scaling and numerical simulations that the final average ejected volume of sub-micron droplets is significantly smaller than that from jetting. We then construct a comprehensive global probability distribution function (PDF) for SSA by rigorously modeling its fundamental components in sequence: (i) refining the sub-surface bubble size distribution with a simpler and better experimentally supported exponential law, and (ii) deriving novel scaling laws for the number and size distribution of droplets per bursting event from a large set of high-resolution numerical simulations. A key finding is that the droplet size PDF from a single bubble follows a highly-skewed distribution – optimally modeled by a Generalized Inverse Gaussian distribution – revealing a prolific production of nanometric droplets previously unaccounted for by simpler models. When integrated, these components yield a final predictive model for the global SSA size distribution, with parameters derived directly from physical principles and simulations rather than empirical fitting. The model demonstrates strong predictive consistency, showing close qualitative agreement with a wide corpus of experimental data from both laboratory and oceanic measurements, particularly across the critical 25 nm to range. By clarifying that jetting is the dominant pathway and providing a robust, physically-grounded predictive tool, this research significantly enhances the fundamental understanding of marine aerosol generation and provides a more accurate foundation for climate and atmospheric chemistry models.
{"title":"The dominant role of jetting in micron- and sub-micron sea spray produced by bubble bursting: A revised model and comparison with measurements","authors":"Alfonso M. Gañán-Calvo , Miguel A. Herrada , José M. López-Herrera","doi":"10.1016/j.apor.2025.104891","DOIUrl":"10.1016/j.apor.2025.104891","url":null,"abstract":"<div><div>The size distribution of sub-micron sea spray aerosols (SSA) is a critical component of climate models, yet the primary physical mechanism governing their production – specifically the competition between film and jet droplets from bubble bursting – has remained a subject of intense debate. This work presents a revised, first-principles model to quantitatively resolve this controversy and demonstrate the dominance of jetting for producing micron and sub-micron aerosols. Our approach first rules out the film droplet mechanism as a primary contributor for this size range by demonstrating through physical scaling and numerical simulations that the final average ejected volume of sub-micron droplets is significantly smaller than that from jetting. We then construct a comprehensive global probability distribution function (PDF) for SSA by rigorously modeling its fundamental components in sequence: (i) refining the sub-surface bubble size distribution with a simpler and better experimentally supported exponential law, and (ii) deriving novel scaling laws for the number and size distribution of droplets per bursting event from a large set of high-resolution numerical simulations. A key finding is that the droplet size PDF from a single bubble follows a highly-skewed distribution – optimally modeled by a Generalized Inverse Gaussian distribution – revealing a prolific production of nanometric droplets previously unaccounted for by simpler models. When integrated, these components yield a final predictive model for the global SSA size distribution, with parameters derived directly from physical principles and simulations rather than empirical fitting. The model demonstrates strong predictive consistency, showing close qualitative agreement with a wide corpus of experimental data from both laboratory and oceanic measurements, particularly across the critical 25 nm to <span><math><mrow><mn>2</mn><mo>.</mo><mn>5</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> range. By clarifying that jetting is the dominant pathway and providing a robust, physically-grounded predictive tool, this research significantly enhances the fundamental understanding of marine aerosol generation and provides a more accurate foundation for climate and atmospheric chemistry models.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104891"},"PeriodicalIF":4.4,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734798","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 : 2025-12-06DOI: 10.1016/j.apor.2025.104882
Zheng Zhang, Shengyi Cong, Liang Tang, Xianzhang Ling, Yun Shi
Liquefaction-induced lateral spreading significantly contributes to pile bending failure in pile-supported wharves. However, the combined effects of axial and lateral loads under such conditions have been insufficiently investigated, and the efficacy of existing reinforcement measures in mitigating such failures has been inadequately evaluated. In this work, the combined effects of lateral (inertial and kinematic) and axial loads on pile response and bending failure were investigated using centrifuge tests and numerical simulations. Various soil–cement retrofitting schemes were analysed to mitigate unfavourable wharf responses, and their contributions to bending failure were explored. A predictive method was developed to assess critical bending failure under retrofitted conditions. The findings indicate that the interaction between increased lateral and axial loads reduces the bending capacity of piles, heightening their vulnerability to bending failure. Notably, retrofitting the interpile soil effectively diminishes profile responses and enhances resistance to bending failure.
{"title":"Evaluation of the impact of soil–cement retrofitting on the failure behaviour of wharf piles in liquefiable soils","authors":"Zheng Zhang, Shengyi Cong, Liang Tang, Xianzhang Ling, Yun Shi","doi":"10.1016/j.apor.2025.104882","DOIUrl":"10.1016/j.apor.2025.104882","url":null,"abstract":"<div><div>Liquefaction-induced lateral spreading significantly contributes to pile bending failure in pile-supported wharves. However, the combined effects of axial and lateral loads under such conditions have been insufficiently investigated, and the efficacy of existing reinforcement measures in mitigating such failures has been inadequately evaluated. In this work, the combined effects of lateral (inertial and kinematic) and axial loads on pile response and bending failure were investigated using centrifuge tests and numerical simulations. Various soil–cement retrofitting schemes were analysed to mitigate unfavourable wharf responses, and their contributions to bending failure were explored. A predictive method was developed to assess critical bending failure under retrofitted conditions. The findings indicate that the interaction between increased lateral and axial loads reduces the bending capacity of piles, heightening their vulnerability to bending failure. Notably, retrofitting the interpile soil effectively diminishes profile responses and enhances resistance to bending failure.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104882"},"PeriodicalIF":4.4,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683710","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 : 2025-12-06DOI: 10.1016/j.apor.2025.104873
Yujia Wang , Dingqi Yang , Linlin Li , Huabin Shi
Efficient and accurate prediction of tropical cyclone induced storm surge is critical to coastal disaster emergency response and recovery. Recently, machine learning (ML) methods have been widely applied to storm surge predictions but there is still notable room for improvement. In this paper, we focus on optimizing the generalization and accuracy of storm surge ML models by integrating hydrodynamics in data featuring and model setups, which can be extended to all categories of ML methods like recurrent neural networks and self-attention deep learning architectures rather than a specific model. First, a surge-gradient-informed data splitting strategy is proposed, in which the maximum gradient of surge level is used as a priori indicator to identify the outliers in the adopted tropical cyclones and these outliers are compulsorily included in the training dataset to improve the model generalization. It is shown that, compared with the common random data splitting, the surge-gradient-informed data splitting has a non-negligible effect on reducing the errors in the predicted rapid increases of surge levels. Further, based on shallow-water hydrodynamics in the motion of coastal water, a gradient-target setup of ML models is suggested which takes the temporal gradient of surge level, rather than directly the surge level, as the output variable of ML models. Correspondingly, according to a comparison study, the combination of historical surge gradient and meteorological-oceanographic conditions is recommended for the input features of gradient-target ML models. This gradient-target setup is tested in four categories of ML models, i.e., XGBoost, LSTM, DLinear, and Multi-head MLP. It is shown that, for forecasts with a lead time of 1-2 hours, the gradient-target setup improves the performances of all four ML models to different extents, especially those of XGBoost and LSTM models. For forecasts with a lead time of over 3 hours, the improvement of ML model performances by using the gradient-target setup diminishes with the lead time and the performances of XGBoost and MLP models are even worsen. Nevertheless, the gradient-target models capture the rapid rising and falling of surge heights more accurately than the surge-target models. The surge-gradient informed data splitting and gradient-target model setup proposed in this study provide an alternative view to incorporating physics into ML models for ocean hydrodynamic disasters.
{"title":"Gradient-informed data splitting and model setup for machine learning prediction of storm surge","authors":"Yujia Wang , Dingqi Yang , Linlin Li , Huabin Shi","doi":"10.1016/j.apor.2025.104873","DOIUrl":"10.1016/j.apor.2025.104873","url":null,"abstract":"<div><div>Efficient and accurate prediction of tropical cyclone induced storm surge is critical to coastal disaster emergency response and recovery. Recently, machine learning (ML) methods have been widely applied to storm surge predictions but there is still notable room for improvement. In this paper, we focus on optimizing the generalization and accuracy of storm surge ML models by integrating hydrodynamics in data featuring and model setups, which can be extended to all categories of ML methods like recurrent neural networks and self-attention deep learning architectures rather than a specific model. First, a surge-gradient-informed data splitting strategy is proposed, in which the maximum gradient of surge level is used as a priori indicator to identify the outliers in the adopted tropical cyclones and these outliers are compulsorily included in the training dataset to improve the model generalization. It is shown that, compared with the common random data splitting, the surge-gradient-informed data splitting has a non-negligible effect on reducing the errors in the predicted rapid increases of surge levels. Further, based on shallow-water hydrodynamics in the motion of coastal water, a gradient-target setup of ML models is suggested which takes the temporal gradient of surge level, rather than directly the surge level, as the output variable of ML models. Correspondingly, according to a comparison study, the combination of historical surge gradient and meteorological-oceanographic conditions is recommended for the input features of gradient-target ML models. This gradient-target setup is tested in four categories of ML models, i.e., XGBoost, LSTM, DLinear, and Multi-head MLP. It is shown that, for forecasts with a lead time of 1-2 hours, the gradient-target setup improves the performances of all four ML models to different extents, especially those of XGBoost and LSTM models. For forecasts with a lead time of over 3 hours, the improvement of ML model performances by using the gradient-target setup diminishes with the lead time and the performances of XGBoost and MLP models are even worsen. Nevertheless, the gradient-target models capture the rapid rising and falling of surge heights more accurately than the surge-target models. The surge-gradient informed data splitting and gradient-target model setup proposed in this study provide an alternative view to incorporating physics into ML models for ocean hydrodynamic disasters.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104873"},"PeriodicalIF":4.4,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734694","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 : 2025-12-06DOI: 10.1016/j.apor.2025.104890
Tao Peng , Rongwu Xu , Jiarui Zhang , Jinwei Liu , Zhenyu Yao
Accurately separating and quantifying the contributions of individual mechanical equipment from coupled noise in ships is critical for further reducing radiated noise from onboard machinery. Transfer Path Analysis (TPA) and Operational Transfer Path Analysis (OTPA) are widely adopted for vibration-noise transfer characterization; however, their efficiency and accuracy in shipboard noise testing scenarios remain limited. To address this challenge, this paper proposes a Reverse Transfer Path Analysis (RTPA) method based on pseudo-force and reciprocity testing principles. This method eliminates the need for machinery disassembly or installation of large-scale exciters, enabling in-situ measurements of equipment excitation forces and frequency response functions, thereby significantly improving testing efficiency. Validation through underwater noise experiments on a scaled ship model demonstrates the effectiveness of RTPA in decoupling machinery noise contributions. Results show excellent agreement with measured data: shaft-related tonal frequencies and amplitudes fully align with ground-truth values, and the broadband noise level error is only 3.1 dB, compared to a 10.3 dB error for the OTPA method. These findings confirm the enhanced accuracy and effectiveness of the RTPA method in resolving coupled noise separation challenges for shipboard machinery, offering robust support for vibration/noise reduction strategies and acoustic optimization in ship design.
{"title":"A study on the separation method of radiation noise contributions from multiple ship equipment based on reverse transfer path analysis","authors":"Tao Peng , Rongwu Xu , Jiarui Zhang , Jinwei Liu , Zhenyu Yao","doi":"10.1016/j.apor.2025.104890","DOIUrl":"10.1016/j.apor.2025.104890","url":null,"abstract":"<div><div>Accurately separating and quantifying the contributions of individual mechanical equipment from coupled noise in ships is critical for further reducing radiated noise from onboard machinery. Transfer Path Analysis (TPA) and Operational Transfer Path Analysis (OTPA) are widely adopted for vibration-noise transfer characterization; however, their efficiency and accuracy in shipboard noise testing scenarios remain limited. To address this challenge, this paper proposes a Reverse Transfer Path Analysis (RTPA) method based on pseudo-force and reciprocity testing principles. This method eliminates the need for machinery disassembly or installation of large-scale exciters, enabling in-situ measurements of equipment excitation forces and frequency response functions, thereby significantly improving testing efficiency. Validation through underwater noise experiments on a scaled ship model demonstrates the effectiveness of RTPA in decoupling machinery noise contributions. Results show excellent agreement with measured data: shaft-related tonal frequencies and amplitudes fully align with ground-truth values, and the broadband noise level error is only 3.1 dB, compared to a 10.3 dB error for the OTPA method. These findings confirm the enhanced accuracy and effectiveness of the RTPA method in resolving coupled noise separation challenges for shipboard machinery, offering robust support for vibration/noise reduction strategies and acoustic optimization in ship design.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104890"},"PeriodicalIF":4.4,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734797","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 : 2025-12-06DOI: 10.1016/j.apor.2025.104879
Xinxing Tan , Dehua Wang , Pu Sun , Tian Lan
Ship carbon emissions have become a global concern, yet significant challenges persist in precise quantification, real-time assessment, and operational optimization. This study proposes an integrated "direct measurement-emission prediction-speed optimization" framework to bridge these gaps. Firstly, a shipboard CO₂ direct measurement system is deployed to collect high-frequency dynamic data. Through synergistic application of domain expertise, statistical methods, and HDBSCAN clustering, erroneous values, anomalies, and outliers are effectively identified and eliminated, yielding a high-confidence fine-grained dataset for microscopic emission analysis and operational decisions. Secondly, four metaheuristic algorithms are incorporated into a dual-adaptive prediction architecture, expanding its mechanistic boundaries to construct a highly reliable and precise CO₂ prediction model. Finally, an Enhanced Equilibrium Optimizer (EEO) with Cauchy mutation strategy demonstrates superior performance in carbon-oriented speed optimization. During a 6-day coastal voyage, EEO algorithm achieves direct carbon reduction of 12.27 tons and 4.11% energy efficiency improvement, realizing synergistic gains in decarbonization and Energy Efficiency Operational Indicator (EEOI). This research provides a holistic technical framework and granular decision support for shipping decarbonization.
{"title":"A triad framework for ship carbon reduction: Direct CO2 measurement, multi-intelligence fusion prediction, and Cauchy-enhanced speed optimization","authors":"Xinxing Tan , Dehua Wang , Pu Sun , Tian Lan","doi":"10.1016/j.apor.2025.104879","DOIUrl":"10.1016/j.apor.2025.104879","url":null,"abstract":"<div><div>Ship carbon emissions have become a global concern, yet significant challenges persist in precise quantification, real-time assessment, and operational optimization. This study proposes an integrated \"direct measurement-emission prediction-speed optimization\" framework to bridge these gaps. Firstly, a shipboard CO₂ direct measurement system is deployed to collect high-frequency dynamic data. Through synergistic application of domain expertise, statistical methods, and HDBSCAN clustering, erroneous values, anomalies, and outliers are effectively identified and eliminated, yielding a high-confidence fine-grained dataset for microscopic emission analysis and operational decisions. Secondly, four metaheuristic algorithms are incorporated into a dual-adaptive prediction architecture, expanding its mechanistic boundaries to construct a highly reliable and precise CO₂ prediction model. Finally, an Enhanced Equilibrium Optimizer (EEO) with Cauchy mutation strategy demonstrates superior performance in carbon-oriented speed optimization. During a 6-day coastal voyage, EEO algorithm achieves direct carbon reduction of 12.27 tons and 4.11% energy efficiency improvement, realizing synergistic gains in decarbonization and Energy Efficiency Operational Indicator (EEOI). This research provides a holistic technical framework and granular decision support for shipping decarbonization.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104879"},"PeriodicalIF":4.4,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683709","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 : 2025-12-04DOI: 10.1016/j.apor.2025.104859
Meysam Khodaei , Ahmed Reda , Adam Schwartzkopff , Ali Karrech
Corrosion-resistant alloy (CRA) liner wrinkling and strain localisation at the triple point present significant challenges to the structural integrity of mechanically lined pipes (MLPs), particularly in girth-welded and weld overlay configurations subjected to bending. This study combines numerical and experimental approaches to evaluate the onset of liner wrinkling and strain localisation at critical weld interfaces. A finite element model (FEM) was developed in ABAQUS and validated against full-scale bending test (FSBT) results. The FEM accurately predicted the mechanical response of MLPs, including wrinkling initiation, deformation patterns, and local axial strains in the triple point region. Strong agreement was achieved between numerical predictions and experimental data, with wrinkling initiation occurring at global tensile strains above the acceptance criteria defined by the Det Norske Veritas (DNV) Joint Industry Project (JIP) guidelines. A parametric study further explored the influence of weld overlay length and internal pressure on wrinkle formation and strain localisation. The results show that while weld overlay length has little effect on wrinkling onset, its local stiffening reduces strain localisation near the triple point. In contrast, internal pressure has a pronounced stabilising effect, substantially delaying liner wrinkling and allowing the pipe to withstand higher bending strains before instability occurs.
{"title":"Numerical and experimental investigation of liner wrinkling and strain localisation in mechanically lined pipes under bending","authors":"Meysam Khodaei , Ahmed Reda , Adam Schwartzkopff , Ali Karrech","doi":"10.1016/j.apor.2025.104859","DOIUrl":"10.1016/j.apor.2025.104859","url":null,"abstract":"<div><div>Corrosion-resistant alloy (CRA) liner wrinkling and strain localisation at the triple point present significant challenges to the structural integrity of mechanically lined pipes (MLPs), particularly in girth-welded and weld overlay configurations subjected to bending. This study combines numerical and experimental approaches to evaluate the onset of liner wrinkling and strain localisation at critical weld interfaces. A finite element model (FEM) was developed in ABAQUS and validated against full-scale bending test (FSBT) results. The FEM accurately predicted the mechanical response of MLPs, including wrinkling initiation, deformation patterns, and local axial strains in the triple point region. Strong agreement was achieved between numerical predictions and experimental data, with wrinkling initiation occurring at global tensile strains above the acceptance criteria defined by the Det Norske Veritas (DNV) Joint Industry Project (JIP) guidelines. A parametric study further explored the influence of weld overlay length and internal pressure on wrinkle formation and strain localisation. The results show that while weld overlay length has little effect on wrinkling onset, its local stiffening reduces strain localisation near the triple point. In contrast, internal pressure has a pronounced stabilising effect, substantially delaying liner wrinkling and allowing the pipe to withstand higher bending strains before instability occurs.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104859"},"PeriodicalIF":4.4,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683711","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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