Pub Date : 2026-01-01DOI: 10.1016/j.apor.2026.104923
Linlong Mu , Tao Zhou , Yimin Lu , Guangming Yu , Jianguo Sun
Compartmented bucket foundations (CBFs) represent a promising alternative to conventional offshore wind turbine foundations, offering enhanced structural stability and bearing capacity. However, the compartmented internal configuration of CBFs complicates the soil-water-structure interaction and poses unique challenges for suction-assisted installation, particularly in sandy soils where seepage effects are prominent. This study presents a series of model tests investigating the suction penetration behavior of both mono bucket foundations (MBFs) and CBFs in homogeneous sand. By varying bucket wall thickness, bulkhead thickness, and mid-chamber size, the influence of compartment geometry on penetration suction was evaluated. Results show that suction installation significantly reduces penetration resistance compared to jacking, which requires up to 8.7 times resistance for MBFs and 15.8 times for CBFs compared to suction-assisted penetration. Additionally, while increased wall and bulkhead thickness lead to higher suction demands, variations in mid-chamber size have minimal impact. Moreover, a theoretical model originally developed for MBFs was extended to incorporate additional bulkhead-induced resistance. The modified model provides accurate predictions for suction pressure, particularly during the stable penetration phase. This work advances the understanding of CBF installation mechanics and offers practical guidance for optimizing suction bucket designs in offshore wind applications.
{"title":"Experimental investigation of suction-assisted penetration of compartmented bucket foundations","authors":"Linlong Mu , Tao Zhou , Yimin Lu , Guangming Yu , Jianguo Sun","doi":"10.1016/j.apor.2026.104923","DOIUrl":"10.1016/j.apor.2026.104923","url":null,"abstract":"<div><div>Compartmented bucket foundations (CBFs) represent a promising alternative to conventional offshore wind turbine foundations, offering enhanced structural stability and bearing capacity. However, the compartmented internal configuration of CBFs complicates the soil-water-structure interaction and poses unique challenges for suction-assisted installation, particularly in sandy soils where seepage effects are prominent. This study presents a series of model tests investigating the suction penetration behavior of both mono bucket foundations (MBFs) and CBFs in homogeneous sand. By varying bucket wall thickness, bulkhead thickness, and mid-chamber size, the influence of compartment geometry on penetration suction was evaluated. Results show that suction installation significantly reduces penetration resistance compared to jacking, which requires up to 8.7 times resistance for MBFs and 15.8 times for CBFs compared to suction-assisted penetration. Additionally, while increased wall and bulkhead thickness lead to higher suction demands, variations in mid-chamber size have minimal impact. Moreover, a theoretical model originally developed for MBFs was extended to incorporate additional bulkhead-induced resistance. The modified model provides accurate predictions for suction pressure, particularly during the stable penetration phase. This work advances the understanding of CBF installation mechanics and offers practical guidance for optimizing suction bucket designs in offshore wind applications.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104923"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.apor.2026.104922
Ehsan Javanmard , Javad A. Mehr , Michael R. Davis , Damien S Holloway , Jason Ali-Lavroff
Efficient roll motion mitigation is essential for ensuring the structural integrity and passenger comfort of high-speed catamarans in oblique seas. Ride Control Systems (RCSs) used by Incat Tasmania wave-piercing catamarans (WPCs) typically consist of a single centrally mounted bow T-Foil and two stern-mounted trim tabs, and roll control relies solely on the independent action of the stern tabs, limiting their effectiveness for heave and pitch while not providing optimal ability to mitigate roll in beam and oblique seas. This study experimentally evaluates a new RCS that integrates dual demihull-mounted bow T-Foils with stern trim tabs. The system was implemented on a 2.5 m scale model of a 112 m Incat Tasmania WPC and tested in calm water at 2.89 m/s (equivalent to 37 knots full-scale) using open-loop step and frequency response experiments. Step response tests assessed heel responses under various demihull T-Foils and stern tab deflection patterns. The most effective heel excitation was achieved when the port and starboard demihull T-Foils and stern tab control surfaces operated in antiphase, increasing the heel range by about 43% compared to the centre bow mounted T-Foil RCS configuration. Frequency response tests demonstrated that the integration of dual T-Foils enhanced the RCS roll excitation capability by 45%. A lumped parameter approach was employed to derive and solve the roll dynamic equation of the model, which accurately predicted the heel responses observed in step response tests, with an average deviation of just 4.7%. It also predicted roll response and phase lag trends across a range of excitation frequencies, closely aligning with experimental trends. These findings highlight the significant improvement in the system’s roll control capability by incorporating demihull-mounted T-Foils into the RCS configuration, providing strong support for the new RCS design and laying the foundation for the development of a roll control algorithm for future closed-loop control experiments.
{"title":"Mitigating roll response of high-speed catamarans by dual Demihull mounted T-Foils, Part 1: Design and validation in calm water open-loop tests","authors":"Ehsan Javanmard , Javad A. Mehr , Michael R. Davis , Damien S Holloway , Jason Ali-Lavroff","doi":"10.1016/j.apor.2026.104922","DOIUrl":"10.1016/j.apor.2026.104922","url":null,"abstract":"<div><div>Efficient roll motion mitigation is essential for ensuring the structural integrity and passenger comfort of high-speed catamarans in oblique seas. Ride Control Systems (RCSs) used by Incat Tasmania wave-piercing catamarans (WPCs) typically consist of a single centrally mounted bow T-Foil and two stern-mounted trim tabs, and roll control relies solely on the independent action of the stern tabs, limiting their effectiveness for heave and pitch while not providing optimal ability to mitigate roll in beam and oblique seas. This study experimentally evaluates a new RCS that integrates dual demihull-mounted bow T-Foils with stern trim tabs. The system was implemented on a 2.5 m scale model of a 112 m Incat Tasmania WPC and tested in calm water at 2.89 m/s (equivalent to 37 knots full-scale) using open-loop step and frequency response experiments. Step response tests assessed heel responses under various demihull T-Foils and stern tab deflection patterns. The most effective heel excitation was achieved when the port and starboard demihull T-Foils and stern tab control surfaces operated in antiphase, increasing the heel range by about 43% compared to the centre bow mounted T-Foil RCS configuration. Frequency response tests demonstrated that the integration of dual T-Foils enhanced the RCS roll excitation capability by 45%. A lumped parameter approach was employed to derive and solve the roll dynamic equation of the model, which accurately predicted the heel responses observed in step response tests, with an average deviation of just 4.7%. It also predicted roll response and phase lag trends across a range of excitation frequencies, closely aligning with experimental trends. These findings highlight the significant improvement in the system’s roll control capability by incorporating demihull-mounted T-Foils into the RCS configuration, providing strong support for the new RCS design and laying the foundation for the development of a roll control algorithm for future closed-loop control experiments.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104922"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.apor.2026.104917
Kevin J. Maki , Hyo-Jin Park , Wenzhe Xu , Bo Woo Nam
Parametric roll is a nonlinear and intermittent dynamical phenomenon that causes damage to or loss of cargo, and poses significant risks for passenger safety and comfort. The current engineering practice to evaluate susceptibility or likelihood of parametric roll requires hours of nonlinear simulation or model tests in many wave conditions from the long-term operation wave scatter diagram. In this paper a novel generative AI method is proposed to learn the specific conditions that lead to parametric roll without the need to perform exhaustive and time consuming Monte Carlo simulations of all wave conditions. The method uses a low fidelity hydrodynamics model to generate the required large set of training data. A distillation process is employed that produces a series of models that can generate new wave conditions that lead to increasingly severe parametric roll behavior. Then the exceedance probabilities derived from the generated wave conditions are shown to closely match those from Monte Carlo simulations, while requiring significantly fewer computations. Finally, the generated wave conditions are verified by performing simulation with a weakly-nonlinear IRF method, confirming the ability of the method to find conditions that lead to pronounced parametric roll responses at a small fraction of the cost relative to the current practice of using Monte Carlo simulation.
{"title":"A Generative AI Model for irregular wave conditions that induce parametric roll","authors":"Kevin J. Maki , Hyo-Jin Park , Wenzhe Xu , Bo Woo Nam","doi":"10.1016/j.apor.2026.104917","DOIUrl":"10.1016/j.apor.2026.104917","url":null,"abstract":"<div><div>Parametric roll is a nonlinear and intermittent dynamical phenomenon that causes damage to or loss of cargo, and poses significant risks for passenger safety and comfort. The current engineering practice to evaluate susceptibility or likelihood of parametric roll requires hours of nonlinear simulation or model tests in many wave conditions from the long-term operation wave scatter diagram. In this paper a novel generative AI method is proposed to learn the specific conditions that lead to parametric roll without the need to perform exhaustive and time consuming Monte Carlo simulations of all wave conditions. The method uses a low fidelity hydrodynamics model to generate the required large set of training data. A distillation process is employed that produces a series of models that can generate new wave conditions that lead to increasingly severe parametric roll behavior. Then the exceedance probabilities derived from the generated wave conditions are shown to closely match those from Monte Carlo simulations, while requiring significantly fewer computations. Finally, the generated wave conditions are verified by performing simulation with a weakly-nonlinear IRF method, confirming the ability of the method to find conditions that lead to pronounced parametric roll responses at a small fraction of the cost relative to the current practice of using Monte Carlo simulation.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104917"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.apor.2026.104926
Jun Liu , Yun-He Zhao , Shu-Ming Yan , Kai Liang , Wen-Gang Qi , Fu-Ping Gao
Vortex-induced vibrations (VIVs) of cylindrical structures present significant challenges in engineering practices. While most existing studies have focused on wall-free scenarios. This work experimentally investigates the combined effects of bed-proximity and mass-damping on the onset of transverse VIVs of an elastically mounted cylinder subjected to turbulent shear flow in a recirculating water flume. The mass-damping parameter Ks was varied from low to high values, with the gap ratio e/D ranging from 2.0 to 0.20. Flow field measurements were conducted using an innovative upward-illumination PIV, structural vibration and associated wake fluctuation were captured concurrently. Experimental findings demonstrate that the critical reduced velocity (Vrcr) for onset of VIV remains highly consistent at e/D > 1.0 under constant Ks, and increases as Ks increased for a fixed value of e/D. Under low-Ks conditions, Vrcr decreases exponentially as e/D falls below 1.0. Conversely, the opposite trend is observed under high-Ks conditions. These contrasting behaviors may be attributed to the competition among multiple factors: in the former case, stronger disturbances to the cylinder and an increasing Strouhal number facilitate the onset of near-bed VIV; in the latter, however, reduced vortex-shedding strength and enhanced energy dissipation capacity suppress the onset of near-bed VIV. Empirical correlations between Vrcr and e/D were established for various values of Ks. A correction factor ψ is proposed to quantitatively characterize the combined bed-proximity and mass-damping effects on Vrcr. The present study thus provides a valuable supplement to the DNV GL guidelines for predicting the onset of VIVs in submarine pipelines near the seabed.
{"title":"Effects of bed-proximity on VIV onset of an elastically mounted circular cylinder with low to high mass-damping parameters","authors":"Jun Liu , Yun-He Zhao , Shu-Ming Yan , Kai Liang , Wen-Gang Qi , Fu-Ping Gao","doi":"10.1016/j.apor.2026.104926","DOIUrl":"10.1016/j.apor.2026.104926","url":null,"abstract":"<div><div>Vortex-induced vibrations (VIVs) of cylindrical structures present significant challenges in engineering practices. While most existing studies have focused on wall-free scenarios. This work experimentally investigates the combined effects of bed-proximity and mass-damping on the onset of transverse VIVs of an elastically mounted cylinder subjected to turbulent shear flow in a recirculating water flume. The mass-damping parameter <em>K</em><sub>s</sub> was varied from low to high values, with the gap ratio <em>e/D</em> ranging from 2.0 to 0.20. Flow field measurements were conducted using an innovative upward-illumination PIV, structural vibration and associated wake fluctuation were captured concurrently. Experimental findings demonstrate that the critical reduced velocity (<em>Vr</em><sub>cr</sub>) for onset of VIV remains highly consistent at <em>e</em>/<em>D</em> > 1.0 under constant <em>K</em><sub>s</sub>, and increases as <em>K</em><sub>s</sub> increased for a fixed value of <em>e/D</em>. Under low-<em>K</em><sub>s</sub> conditions, <em>Vr</em><sub>cr</sub> decreases exponentially as <em>e/D</em> falls below 1.0. Conversely, the opposite trend is observed under high-<em>K</em><sub>s</sub> conditions. These contrasting behaviors may be attributed to the competition among multiple factors: in the former case, stronger disturbances to the cylinder and an increasing Strouhal number facilitate the onset of near-bed VIV; in the latter, however, reduced vortex-shedding strength and enhanced energy dissipation capacity suppress the onset of near-bed VIV. Empirical correlations between <em>Vr</em><sub>cr</sub> and <em>e/D</em> were established for various values of <em>K</em><sub>s</sub>. A correction factor <em>ψ</em> is proposed to quantitatively characterize the combined bed-proximity and mass-damping effects on <em>Vr</em><sub>cr</sub>. The present study thus provides a valuable supplement to the DNV GL guidelines for predicting the onset of VIVs in submarine pipelines near the seabed.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104926"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.apor.2025.104906
Zhiqiang Liu , Biao Wang , Fuxiang Hu , Rong Wan , Cheng Zhou
Quantitative sampling of ichthyoplankton is a critical tool for estimating recruitment abundance and supporting the sustainable management of fishery resources. This study introduces a novel multiple codend release mechanism utilizing an electromagnetic induction device as part of an autonomous multiple codend opening/closing system for sampling nets. The electromagnetic induction mechanism operates solely on the principle of electromagnetism to open and close codends, significantly reducing the reliance on mechanical components compared to traditional motor-triggered systems. Furthermore, an intelligent control system integrating automatic and remote modes via acoustic communication has been developed, allowing researchers to select the appropriate mode based on varying operational conditions and requirements. These advancements demonstrated strong stability and reliability in both controlled tests and sea trials. Collectively, the newly developed multiple codend release mechanism and intelligent control system offer a foundational reference for enhancing the efficiency and adaptability of multiple sampling nets.
{"title":"Development of a novel intelligent control system for an autonomous multiple codend opening/closing mechanism in sampling nets","authors":"Zhiqiang Liu , Biao Wang , Fuxiang Hu , Rong Wan , Cheng Zhou","doi":"10.1016/j.apor.2025.104906","DOIUrl":"10.1016/j.apor.2025.104906","url":null,"abstract":"<div><div>Quantitative sampling of ichthyoplankton is a critical tool for estimating recruitment abundance and supporting the sustainable management of fishery resources. This study introduces a novel multiple codend release mechanism utilizing an electromagnetic induction device as part of an autonomous multiple codend opening/closing system for sampling nets. The electromagnetic induction mechanism operates solely on the principle of electromagnetism to open and close codends, significantly reducing the reliance on mechanical components compared to traditional motor-triggered systems. Furthermore, an intelligent control system integrating automatic and remote modes via acoustic communication has been developed, allowing researchers to select the appropriate mode based on varying operational conditions and requirements. These advancements demonstrated strong stability and reliability in both controlled tests and sea trials. Collectively, the newly developed multiple codend release mechanism and intelligent control system offer a foundational reference for enhancing the efficiency and adaptability of multiple sampling nets.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104906"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.apor.2026.104918
Daiyu Zhang, Zhenwei Liu, Chaoming Bao, Qian Liu, Junming Hu
In the shape optimization of underwater gliders, conventional geometric parameterization methods usually require a large number of design variables to ensure sufficient shape representation capability, which in turn leads to excessive optimization iterations, high CFD computational cost, and low optimization efficiency. To address this “high-dimensional and high-cost” issue, this paper proposes a shape optimization design method based on principal component analysis (PCA) geometric dimensionality reduction and Kriging inverse mapping for a blended-wing-body underwater glider (BWBUG). In this method, firstly, PCA is employed to the conventional geometric parameterization variables, significantly reducing the dimensionality of the design variables while preserving the principal shape variation features. Subsequently, a Kriging inverse mapping model is constructed between the reduced-dimensional variables and the original parameterization variables, enabling reversible reconstruction from the low-dimensional feature space to the original parameter space. On this basis, a shape optimization design framework based on geometric parameterization dimensionality reduction for a BWBUG is established, which effectively reduces computational cost and significantly improves optimization efficiency. To validate the effectiveness and efficiency of the proposed method, a shape optimization case study is conducted on a BWBUG. The results show that, by reducing 12 geometric parameters to 4 principal components, 98.36% of the shape deformation information is retained, while the number of CFD evaluations during the optimization process is reduced by 64, and the lift-to-drag ratio () is effectively improved.
{"title":"A shape optimization design method based on PCA geometric dimensionality reduction and Kriging inverse mapping for a blended-wing-body underwater glider","authors":"Daiyu Zhang, Zhenwei Liu, Chaoming Bao, Qian Liu, Junming Hu","doi":"10.1016/j.apor.2026.104918","DOIUrl":"10.1016/j.apor.2026.104918","url":null,"abstract":"<div><div>In the shape optimization of underwater gliders, conventional geometric parameterization methods usually require a large number of design variables to ensure sufficient shape representation capability, which in turn leads to excessive optimization iterations, high CFD computational cost, and low optimization efficiency. To address this “high-dimensional and high-cost” issue, this paper proposes a shape optimization design method based on principal component analysis (PCA) geometric dimensionality reduction and Kriging inverse mapping for a blended-wing-body underwater glider (BWBUG). In this method, firstly, PCA is employed to the conventional geometric parameterization variables, significantly reducing the dimensionality of the design variables while preserving the principal shape variation features. Subsequently, a Kriging inverse mapping model is constructed between the reduced-dimensional variables and the original parameterization variables, enabling reversible reconstruction from the low-dimensional feature space to the original parameter space. On this basis, a shape optimization design framework based on geometric parameterization dimensionality reduction for a BWBUG is established, which effectively reduces computational cost and significantly improves optimization efficiency. To validate the effectiveness and efficiency of the proposed method, a shape optimization case study is conducted on a BWBUG. The results show that, by reducing 12 geometric parameters to 4 principal components, 98.36% of the shape deformation information is retained, while the number of CFD evaluations during the optimization process is reduced by 64, and the lift-to-drag ratio (<span><math><mrow><mi>L</mi><mo>/</mo><mi>D</mi></mrow></math></span>) is effectively improved.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104918"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.apor.2025.104898
Shayesteh Hafezi, Xianliang Gong, Yulin Pan
In this paper, we develop an efficient method to evaluate the temporal exceeding probability of ship motion (percentage of time for the ship motion to be above a given high threshold) in an irregular wave field. Our method builds on our previous work Gong et al. (2022), which converts the calculation into a sampling problem in the space of wave group parameters, within which an acquisition-based sequential sampling method is developed to reduce the number of required samples. Two critical advancements are achieved in this paper relative to Gong et al. (2022). (1) We develop a new wave group parameterization method, which allows the framework to be applied to general broadband wave fields. (2) We incorporate the variability regarding each parameterized wave group (e.g., varying wave form and initial condition of the ship encountering the group) into the final estimation of a single value of the temporal exceeding probability. Our complete framework is tested for a ship subject to a wave field with a JONSWAP spectrum, for different ship motion dynamical models, spectral bandwidths, and exceeding thresholds. The results show that for most cases our method provides a result with O(15 %) error or below within 210 samples, with the ground truth obtained from a continuous simulation that is more than 2300 times more expensive than our method. We also demonstrate the benefits of sequential sampling (with an acquisition function updated due to (2)) compared to standard random or Latin hypercube (LH) samplings, in terms of the mean error of the results.
{"title":"Efficient estimation of temporal exceeding probability for ship responses in broadband wave fields","authors":"Shayesteh Hafezi, Xianliang Gong, Yulin Pan","doi":"10.1016/j.apor.2025.104898","DOIUrl":"10.1016/j.apor.2025.104898","url":null,"abstract":"<div><div>In this paper, we develop an efficient method to evaluate the temporal exceeding probability of ship motion (percentage of time for the ship motion to be above a given high threshold) in an irregular wave field. Our method builds on our previous work Gong et al. (2022), which converts the calculation into a sampling problem in the space of wave group parameters, within which an acquisition-based sequential sampling method is developed to reduce the number of required samples. Two critical advancements are achieved in this paper relative to Gong et al. (2022). (1) We develop a new wave group parameterization method, which allows the framework to be applied to general broadband wave fields. (2) We incorporate the variability regarding each parameterized wave group (e.g., varying wave form and initial condition of the ship encountering the group) into the final estimation of a single value of the temporal exceeding probability. Our complete framework is tested for a ship subject to a wave field with a JONSWAP spectrum, for different ship motion dynamical models, spectral bandwidths, and exceeding thresholds. The results show that for most cases our method provides a result with O(15<!--> <!-->%) error or below within 210 samples, with the ground truth obtained from a continuous simulation that is more than 2300 times more expensive than our method. We also demonstrate the benefits of sequential sampling (with an acquisition function updated due to (2)) compared to standard random or Latin hypercube (LH) samplings, in terms of the mean error of the results.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104898"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.apor.2025.104907
Xin Xiong, Rudy R. Negenborn, Yusong Pang
Existing studies on multi-vessel formations rarely combine physically based models of ship–ship hydrodynamic interaction with online formation control, so that energy benefits are typically assessed offline or only approximated through artificial potentials. This paper addresses this gap by embedding a reduced-order, hydrodynamics-aware resistance model into a hierarchical formation control framework for multi vessel systems. A three degree of freedom interaction model is incorporated into the cost function, enabling the supervisory controller to adaptively optimize inter ship spacing and formation geometry in a speed dependent and hydrodynamics aware manner. The lower level MPC ensures accurate trajectory tracking and stability under the guidance of the top level optimization. Four simulation studies are conducted to evaluate the proposed method. The platooning formation is first analyzed as a reference, followed by the triangular formation, which achieves balanced tracking performance and stability. The echelon formation is then examined, demonstrating significant energy savings in medium to high speed regimes while maintaining yaw stability. Finally, an unconstrained optimization scenario is explored, where the system autonomously adapts its geometry without prescribed patterns, revealing emergent energy efficient and stable arrangements across different speed ranges. Results show that the proposed approach not only reduces resistance and improves energy efficiency but also enhances formation adaptability and robustness under varying operating conditions. These findings provide new insights into hydrodynamics aware cooperative control and the development of energy conscious fleet management strategies for future maritime transportation.
{"title":"Energy efficient formation control of multi vessel systems via hydrodynamics aware configuration optimization","authors":"Xin Xiong, Rudy R. Negenborn, Yusong Pang","doi":"10.1016/j.apor.2025.104907","DOIUrl":"10.1016/j.apor.2025.104907","url":null,"abstract":"<div><div>Existing studies on multi-vessel formations rarely combine physically based models of ship–ship hydrodynamic interaction with online formation control, so that energy benefits are typically assessed offline or only approximated through artificial potentials. This paper addresses this gap by embedding a reduced-order, hydrodynamics-aware resistance model into a hierarchical formation control framework for multi vessel systems. A three degree of freedom interaction model is incorporated into the cost function, enabling the supervisory controller to adaptively optimize inter ship spacing and formation geometry in a speed dependent and hydrodynamics aware manner. The lower level MPC ensures accurate trajectory tracking and stability under the guidance of the top level optimization. Four simulation studies are conducted to evaluate the proposed method. The platooning formation is first analyzed as a reference, followed by the triangular formation, which achieves balanced tracking performance and stability. The echelon formation is then examined, demonstrating significant energy savings in medium to high speed regimes while maintaining yaw stability. Finally, an unconstrained optimization scenario is explored, where the system autonomously adapts its geometry without prescribed patterns, revealing emergent energy efficient and stable arrangements across different speed ranges. Results show that the proposed approach not only reduces resistance and improves energy efficiency but also enhances formation adaptability and robustness under varying operating conditions. These findings provide new insights into hydrodynamics aware cooperative control and the development of energy conscious fleet management strategies for future maritime transportation.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104907"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.apor.2025.104912
Linjian Wu , Bingli Peng , Jichao Lei , Tingting Li , Mingwei Liu , Bo Liu , Yitao Xiao
Estuarine ship-locks are the navigational structures closest to the sea, which can form a unique seawater corrosive environment characterized by low chlorine-salt concentrations and high-frequency drying‒wetting cycles. Such an environment is caused by the downstream saltwater tides infiltrating into the ship-lock chamber and coupled with the filling and drainage water processes during the ship-lock operation. This unique seawater corrosive environment can seriously threaten the durability of estuarine ship-locks concrete structures. Currently, the chloride transport mechanisms in concrete for estuarine ship-locks under such a unique seawater corrosive environment remain elusive. Particularly, the transport characteristics of chloride invasion into estuarine ship-lock concrete structures, driven by drying-wetting cycle environmental factors, necessitate further study. This paper investigates the effects of drying‒wetting cycle environmental factors of the unique seawater corrosive environment, including the environmental chloride salt concentration, the drying‒wetting frequency, and the drying‒wetting ratio, on the chloride transport in estuarine ship-lock concrete structure by carrying out a physical experimental study. Results indicated an "M"-shaped trend in chloride concentration, surface chloride concentration, and chloride diffusion coefficient of concrete with an increasing drying-wetting ratio. Additionally, the aforementioned chloride transport parameters exhibited a positive correlation with the increase of drying-wetting frequency and environmental chlorine-salt concentration. Notably, the environmental chlorine-salt concentration had the greatest influence on chloride transport, whereas the high-frequency drying-wetting cycles can diminish the promotion degree of environmental chlorine-salt concentration on chloride transport behaviors in concrete. Furthermore, the time-varying patterns of surface chloride concentration and apparent chloride diffusion coefficient in the estuarine ship-lock concrete structures, subjected to different drying-wetting ratios under low chlorine-salt concentrations and high-frequency drying‒wetting cycles, were quantified, and the mathematical relationship between the drying-wetting ratios and ship-lock structural elevation was derived. On the basis of Fick's second law, a computational model of chloride transport in estuarine ship-lock concrete structure was developed, incorporating the influence of structural elevation, i.e., drying-wetting ratios.
{"title":"Chloride transport in estuarine ship-lock concrete structure exposed to a unique seawater corrosive environment with low chlorine-salt concentrations and high-frequency drying‒wetting cycles: Experimental study and computational model","authors":"Linjian Wu , Bingli Peng , Jichao Lei , Tingting Li , Mingwei Liu , Bo Liu , Yitao Xiao","doi":"10.1016/j.apor.2025.104912","DOIUrl":"10.1016/j.apor.2025.104912","url":null,"abstract":"<div><div>Estuarine ship-locks are the navigational structures closest to the sea, which can form a unique seawater corrosive environment characterized by low chlorine-salt concentrations and high-frequency drying‒wetting cycles. Such an environment is caused by the downstream saltwater tides infiltrating into the ship-lock chamber and coupled with the filling and drainage water processes during the ship-lock operation. This unique seawater corrosive environment can seriously threaten the durability of estuarine ship-locks concrete structures. Currently, the chloride transport mechanisms in concrete for estuarine ship-locks under such a unique seawater corrosive environment remain elusive. Particularly, the transport characteristics of chloride invasion into estuarine ship-lock concrete structures, driven by drying-wetting cycle environmental factors, necessitate further study. This paper investigates the effects of drying‒wetting cycle environmental factors of the unique seawater corrosive environment, including the environmental chloride salt concentration, the drying‒wetting frequency, and the drying‒wetting ratio, on the chloride transport in estuarine ship-lock concrete structure by carrying out a physical experimental study. Results indicated an \"M\"-shaped trend in chloride concentration, surface chloride concentration, and chloride diffusion coefficient of concrete with an increasing drying-wetting ratio. Additionally, the aforementioned chloride transport parameters exhibited a positive correlation with the increase of drying-wetting frequency and environmental chlorine-salt concentration. Notably, the environmental chlorine-salt concentration had the greatest influence on chloride transport, whereas the high-frequency drying-wetting cycles can diminish the promotion degree of environmental chlorine-salt concentration on chloride transport behaviors in concrete. Furthermore, the time-varying patterns of surface chloride concentration and apparent chloride diffusion coefficient in the estuarine ship-lock concrete structures, subjected to different drying-wetting ratios under low chlorine-salt concentrations and high-frequency drying‒wetting cycles, were quantified, and the mathematical relationship between the drying-wetting ratios and ship-lock structural elevation was derived. On the basis of Fick's second law, a computational model of chloride transport in estuarine ship-lock concrete structure was developed, incorporating the influence of structural elevation, i.e., drying-wetting ratios.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104912"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.apor.2026.104925
Mohammed Diykh , Mumtaz Ali , Aitazaz Ahsan Farooque , Anwar Ali Aldhafeeri , Abdulhaleem H. Labban
Sea level variability is an urgent climate risk, threatening to vanish islands and coastal areas. Forecasting future sea level rise accurately is fundamental to support experts for flooding and erosion control. In this paper, a novel sea level variability forecast model (CG-CEEMDANHFS-AEM) is proposed integrating correlation graph (CG), a complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), Hilbert feature selection approach (HFS), adaptive ensemble model (AEM), and oppositional learning sparrow search algorithm (OLSSA). The AEM is a novel ensemble model that combines the strengths of GRU, self-attention LSTM and XGBoost models based on dynamic weights assignment strategy, adjusting to real-time changes in sea level rise by updating the weights according to the error and performance of the models. Firstly, the input data is pre-processed using correlation graph to remove lower correlated variables and fill the missing values in the data. After that the CEEMDAN technique is employed to decompose the data, followed by HFS to select the most efficient features. The selected features are then employed into the AEM model where the OLSSA is adopted to select the optimal hyper-parameters of the proposed model. To verify the efficiency of the proposed CG-CEEMDANHFS-AEM against comparing models, extensive experiments were conducted to forecast sea level variability for Hillary and Burnie stations in Australia. The results shows that the proposed model obtained the highest accuracy in terms of goodness-of-fit metrics against the state-of-the-art benchmark comparing models. The proposed model can offer a valuable tool for coastal planning and policy making under the recent climate change.
{"title":"Designing robust adaptive ensemble deep learning based decomposition technique for sea level variability prediction","authors":"Mohammed Diykh , Mumtaz Ali , Aitazaz Ahsan Farooque , Anwar Ali Aldhafeeri , Abdulhaleem H. Labban","doi":"10.1016/j.apor.2026.104925","DOIUrl":"10.1016/j.apor.2026.104925","url":null,"abstract":"<div><div>Sea level variability is an urgent climate risk, threatening to vanish islands and coastal areas. Forecasting future sea level rise accurately is fundamental to support experts for flooding and erosion control. In this paper, a novel sea level variability forecast model (CG-CEEMDAN<img>HFS-AEM) is proposed integrating correlation graph (CG), a complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN), Hilbert feature selection approach (HFS), adaptive ensemble model (AEM), and oppositional learning sparrow search algorithm (OLSSA). The AEM is a novel ensemble model that combines the strengths of GRU, self-attention LSTM and XGBoost models based on dynamic weights assignment strategy, adjusting to real-time changes in sea level rise by updating the weights according to the error and performance of the models. Firstly, the input data is pre-processed using correlation graph to remove lower correlated variables and fill the missing values in the data. After that the CEEMDAN technique is employed to decompose the data, followed by HFS to select the most efficient features. The selected features are then employed into the AEM model where the OLSSA is adopted to select the optimal hyper-parameters of the proposed model. To verify the efficiency of the proposed CG-CEEMDAN<img>HFS-AEM against comparing models, extensive experiments were conducted to forecast sea level variability for Hillary and Burnie stations in Australia. The results shows that the proposed model obtained the highest accuracy in terms of goodness-of-fit metrics against the state-of-the-art benchmark comparing models. The proposed model can offer a valuable tool for coastal planning and policy making under the recent climate change.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"166 ","pages":"Article 104925"},"PeriodicalIF":4.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145921002","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号