Pub Date : 2026-01-09DOI: 10.1016/j.oceaneng.2026.124223
Jing Tang Xing , Guiyong Zhang , Zhe Sun , Jingzhe Jin , Dominic Hudson
This paper provides a type of floating wind-turbine to reduce vibrations excited by sea-waves and to collect wave-energy. The idea is to partly-replace some passive-dampers in current floating-wind-turbines by electromagnetic-isolators to reach the aim. The theoretical analysis and the solution of system are presented, based on which the numerical calculations for dynamic response-curves are given. The results show the proposed system is effective to reduce vibrations of floating wind turbine excited by sea-waves and to collect wave energy for it safely to operate in sea-environments. It is found that due to interactions and water added mass, the pre-designed same frequency of floating-turbine and electromagnetic-isolator as a dynamic absorber is separated, of which the lower frequency about 0.75 is the floating turbine one affected by the water added mass. The numerical results at frequency 0.75 with varying electromagnetic damping values reveal that the best damping 0.15 of electromagnetic isolator with the energy collection rate of constant 0.95. Some guidelines for possible practical design of this type of integrated system by using the developed theory are suggested, which would be an important reference for practical designs. A discussion is given for possible research directions on this integrated floating wave-wind harvesting system.
{"title":"Theoretical and numerical investigations on an integrated sea-wave-floating wind turbine energy harvesting system","authors":"Jing Tang Xing , Guiyong Zhang , Zhe Sun , Jingzhe Jin , Dominic Hudson","doi":"10.1016/j.oceaneng.2026.124223","DOIUrl":"10.1016/j.oceaneng.2026.124223","url":null,"abstract":"<div><div>This paper provides a type of floating wind-turbine to reduce vibrations excited by sea-waves and to collect wave-energy. The idea is to partly-replace some passive-dampers in current floating-wind-turbines by electromagnetic-isolators to reach the aim. The theoretical analysis and the solution of system are presented, based on which the numerical calculations for dynamic response-curves are given. The results show the proposed system is effective to reduce vibrations of floating wind turbine excited by sea-waves and to collect wave energy for it safely to operate in sea-environments. It is found that due to interactions and water added mass, the pre-designed same frequency of floating-turbine and electromagnetic-isolator as a dynamic absorber is separated, of which the lower frequency about 0.75 is the floating turbine one affected by the water added mass. The numerical results at frequency 0.75 with varying electromagnetic damping values reveal that the best damping 0.15 of electromagnetic isolator with the energy collection rate of constant 0.95. Some guidelines for possible practical design of this type of integrated system by using the developed theory are suggested, which would be an important reference for practical designs. A discussion is given for possible research directions on this integrated floating wave-wind harvesting system.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"349 ","pages":"Article 124223"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928575","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 : 2026-01-09DOI: 10.1016/j.oceaneng.2025.124140
Dong-Woo Kim , Myung-Il Roh , Yong-Tai Kim , Minkyu Park , Mun-gwan Choi , Jin-Hyeok Kim
With tightening environmental regulations, demand for eco-friendly fuels has been increasing, driving a steady rise in orders for LNG-fueled ships and LNG carriers. In particular, the demand for membrane-type LNG carriers, which offer excellent safety and economic efficiency, has been growing significantly. However, sloshing during operation significantly impacts the structural integrity of cargo tanks, and high-amplitude sloshing loads can cause permanent damage. Traditional linear-based sloshing assessment methods provide conservative, relatively safe results but fail to capture the nonlinear characteristics of actual sloshing loads adequately. Although several classification societies have proposed assessment procedures that incorporate structural nonlinearity, further refinement is required for practical application. In this study, an improved sloshing assessment methodology that considers structural nonlinearity was proposed, based on Lloyd's Register (LR) procedures, and applied to the MARK III Flex cargo containment system (CCS) of a 174K LNG carrier. Model tests were conducted to define the expected ranges of peak pressure and rising time. In addition, numerical simulations incorporating strain-rate effects and the plastic deformation behavior of R-PUF (reinforced polyurethane foam) under sloshing loads were performed, and the predicted dynamic responses were validated against experimental results. Furthermore, empirical formulations of the dynamic response factor were derived for different failure modes of CCS components. Finally, the utilization factor of the MARK III Flex CCS was evaluated using sloshing loads obtained from the 174K LNG carrier model tests, thereby validating the practicality and reliability of the proposed methodology. The proposed method quantitatively accounts for the structural nonlinear response of the MARK III Flex CCS to sloshing loads while considering hull stiffness, thereby balancing prediction accuracy and engineering practicality for practical applications.
随着环保法规的加强，对环保燃料的需求不断增加，LNG燃料船和LNG运输船的订单稳步增加。特别是，对具有优异安全性和经济性的膜型LNG运输船的需求一直在显著增长。然而，在运行过程中，晃动会严重影响货舱的结构完整性，并且高振幅的晃动载荷会造成永久性损伤。传统的基于线性的晃动评估方法提供了保守的、相对安全的结果，但未能充分捕捉实际晃动载荷的非线性特征。虽然有几个船级社提出了纳入结构非线性的评估程序，但实际应用需要进一步改进。在这项研究中，基于英国劳氏船级社（LR）的程序，提出了一种考虑结构非线性的改进晃动评估方法，并应用于174K LNG运输船的MARK III Flex货物密封系统（CCS）。通过模型试验确定了峰值压力和上升时间的预期范围。结合应变率效应和R-PUF（增强聚氨酯泡沫）在晃动载荷下的塑性变形行为进行了数值模拟，并将预测的动态响应与实验结果进行了验证。在此基础上，推导了不同破坏模式下CCS构件动态响应因子的经验表达式。最后，使用从174K LNG运输船模型试验中获得的晃动载荷对MARK III Flex CCS的利用系数进行了评估，从而验证了所提出方法的实用性和可靠性。提出的方法在考虑船体刚度的同时，定量地考虑了MARK III Flex CCS对晃动载荷的结构非线性响应，从而在实际应用中平衡了预测精度和工程实用性。
{"title":"A nonlinear methodology for the sloshing assessment in the membrane-type LNG cargo containment system","authors":"Dong-Woo Kim , Myung-Il Roh , Yong-Tai Kim , Minkyu Park , Mun-gwan Choi , Jin-Hyeok Kim","doi":"10.1016/j.oceaneng.2025.124140","DOIUrl":"10.1016/j.oceaneng.2025.124140","url":null,"abstract":"<div><div>With tightening environmental regulations, demand for eco-friendly fuels has been increasing, driving a steady rise in orders for LNG-fueled ships and LNG carriers. In particular, the demand for membrane-type LNG carriers, which offer excellent safety and economic efficiency, has been growing significantly. However, sloshing during operation significantly impacts the structural integrity of cargo tanks, and high-amplitude sloshing loads can cause permanent damage. Traditional linear-based sloshing assessment methods provide conservative, relatively safe results but fail to capture the nonlinear characteristics of actual sloshing loads adequately. Although several classification societies have proposed assessment procedures that incorporate structural nonlinearity, further refinement is required for practical application. In this study, an improved sloshing assessment methodology that considers structural nonlinearity was proposed, based on Lloyd's Register (LR) procedures, and applied to the MARK III Flex cargo containment system (CCS) of a 174K LNG carrier. Model tests were conducted to define the expected ranges of peak pressure and rising time. In addition, numerical simulations incorporating strain-rate effects and the plastic deformation behavior of R-PUF (reinforced polyurethane foam) under sloshing loads were performed, and the predicted dynamic responses were validated against experimental results. Furthermore, empirical formulations of the dynamic response factor were derived for different failure modes of CCS components. Finally, the utilization factor of the MARK III Flex CCS was evaluated using sloshing loads obtained from the 174K LNG carrier model tests, thereby validating the practicality and reliability of the proposed methodology. The proposed method quantitatively accounts for the structural nonlinear response of the MARK III Flex CCS to sloshing loads while considering hull stiffness, thereby balancing prediction accuracy and engineering practicality for practical applications.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"349 ","pages":"Article 124140"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928480","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 : 2026-01-09DOI: 10.1016/j.oceaneng.2026.124225
Ziguang Jia , Xin Wang , Wei Li , Sichong Ma , Kuankuan Wu , Yan Qu
To address the challenge of scarce measured data on the structural response of offshore platforms in ice-covered regions, this study proposes a virtual-to-field data-driven modeling approach. Virtual data generated through numerical simulation is used to train a machine learning model, which is then successfully transferred to field measurements for prediction. Based on ice thickness and velocity data from the Bohai Sea, a finite element model of the conical offshore platform is established to simulate the structural response induced by ice loads—these loads are generated from an ice force model. A dataset of 300 cases linking ice parameters to acceleration extremes was constructed and used to train three machine learning models(multilayer perceptron, random forest, and support vector machine)with hyperparameters optimized via particle swarm optimization. The SVM model demonstrated superior performance, achieving high accuracy and strong generalization in both numerical and field validations. The effectiveness of the proposed method for cross-domain prediction are further confirmed through field verification at the JZ20-2 NW platform. This study offers a viable solution for inverting structural responses under data-scarce conditions, demonstrating significant potential for engineering applications.
{"title":"Ice-induced response prediction of offshore platforms via virtual-to-field data-driven modeling under scarce data conditions","authors":"Ziguang Jia , Xin Wang , Wei Li , Sichong Ma , Kuankuan Wu , Yan Qu","doi":"10.1016/j.oceaneng.2026.124225","DOIUrl":"10.1016/j.oceaneng.2026.124225","url":null,"abstract":"<div><div>To address the challenge of scarce measured data on the structural response of offshore platforms in ice-covered regions, this study proposes a virtual-to-field data-driven modeling approach. Virtual data generated through numerical simulation is used to train a machine learning model, which is then successfully transferred to field measurements for prediction. Based on ice thickness and velocity data from the Bohai Sea, a finite element model of the conical offshore platform is established to simulate the structural response induced by ice loads—these loads are generated from an ice force model. A dataset of 300 cases linking ice parameters to acceleration extremes was constructed and used to train three machine learning models(multilayer perceptron, random forest, and support vector machine)with hyperparameters optimized via particle swarm optimization. The SVM model demonstrated superior performance, achieving high accuracy and strong generalization in both numerical and field validations. The effectiveness of the proposed method for cross-domain prediction are further confirmed through field verification at the JZ20-2 NW platform. This study offers a viable solution for inverting structural responses under data-scarce conditions, demonstrating significant potential for engineering applications.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"349 ","pages":"Article 124225"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928478","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 : 2026-01-09DOI: 10.1016/j.oceaneng.2026.124217
Jingkai Chen , Lei Yang , Xiuquan Liu , Dan Sui , Yanting Zhang , Yongwang Liu
Drill string vibration contributes largely to the premature failure of drill pipes and is crucial to ensure the safety and integrity of offshore drilling. However, a fast and accurate drill string vibration prediction is still challenging. This paper begins with a physical model of coupled axial torsional drill string vibrations using the lumped mass method. Based on the fact that vibration propagation can be represented by the modal decomposition, a neural network model is constructed and trained. The dynamic responses on certain locations on the drill string are utilized as the input of neural network model to predict the responses of each mode shapes; and the vibration propagation along the whole drill string can be reconstructed by the super-position of different mode shapes and their corresponding time-variant parameters. Finally, the performance of the neural network model on predicting dynamic responses of the drill string is discussed. The numbers of sensors and the deployment location are critical on the performance of the neural network model and are intensively discussed. This study provides a novel approach available for the real time prediction of drill string vibration and casts light on the future applications of artificial intelligence in offshore drilling engineering.
{"title":"A neural network prediction of drill string axial torsional vibration propagation","authors":"Jingkai Chen , Lei Yang , Xiuquan Liu , Dan Sui , Yanting Zhang , Yongwang Liu","doi":"10.1016/j.oceaneng.2026.124217","DOIUrl":"10.1016/j.oceaneng.2026.124217","url":null,"abstract":"<div><div>Drill string vibration contributes largely to the premature failure of drill pipes and is crucial to ensure the safety and integrity of offshore drilling. However, a fast and accurate drill string vibration prediction is still challenging. This paper begins with a physical model of coupled axial torsional drill string vibrations using the lumped mass method. Based on the fact that vibration propagation can be represented by the modal decomposition, a neural network model is constructed and trained. The dynamic responses on certain locations on the drill string are utilized as the input of neural network model to predict the responses of each mode shapes; and the vibration propagation along the whole drill string can be reconstructed by the super-position of different mode shapes and their corresponding time-variant parameters. Finally, the performance of the neural network model on predicting dynamic responses of the drill string is discussed. The numbers of sensors and the deployment location are critical on the performance of the neural network model and are intensively discussed. This study provides a novel approach available for the real time prediction of drill string vibration and casts light on the future applications of artificial intelligence in offshore drilling engineering.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"349 ","pages":"Article 124217"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928572","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 : 2026-01-09DOI: 10.1016/j.oceaneng.2026.124215
Tao Liu , Junhao Huang , Jintao Zhao , Dongye Liu , Zijian Shen , Zhenglin Li
Autonomous Underwater Vehicles (AUVs) must fulfill multiple critical requirements, including operational safety, navigation efficiency, and environmental adaptability, when performing navigation tasks in complex underwater environments. To address this challenge, this paper proposes a Safe Diffusion Q-learning (SDQ) algorithm. The core of this approach is a diffusion model-based policy network, which leverages the powerful generative capacity of diffusion models to represent complex action distributions, thereby effectively capturing the multi-modal behavioral characteristics inherent in offline datasets. Building upon this architecture, a composite loss function is designed to integrate three key objectives: behavior cloning, value function improvement, and safety constraints. Specifically, this function preserves effective behavioral patterns from the offline data while optimizing the long-term cumulative return through a Q-learning mechanism. Furthermore, it explicitly incorporates a safety constraint based on the Conditional Value at Risk (CVaR) to proactively avoid hazardous actions. Simulation results demonstrate that the proposed SDQ algorithm outperforms several mainstream baseline methods in terms of navigation efficiency, obstacle avoidance safety, and mission success rate. Additionally, in tests involving time-varying ocean current disturbances, SDQ exhibits notable robustness.
{"title":"Safe diffusion Q-learning: A hybrid method combining diffusion model and constrained reinforcement learning for AUV navigation","authors":"Tao Liu , Junhao Huang , Jintao Zhao , Dongye Liu , Zijian Shen , Zhenglin Li","doi":"10.1016/j.oceaneng.2026.124215","DOIUrl":"10.1016/j.oceaneng.2026.124215","url":null,"abstract":"<div><div>Autonomous Underwater Vehicles (AUVs) must fulfill multiple critical requirements, including operational safety, navigation efficiency, and environmental adaptability, when performing navigation tasks in complex underwater environments. To address this challenge, this paper proposes a Safe Diffusion Q-learning (SDQ) algorithm. The core of this approach is a diffusion model-based policy network, which leverages the powerful generative capacity of diffusion models to represent complex action distributions, thereby effectively capturing the multi-modal behavioral characteristics inherent in offline datasets. Building upon this architecture, a composite loss function is designed to integrate three key objectives: behavior cloning, value function improvement, and safety constraints. Specifically, this function preserves effective behavioral patterns from the offline data while optimizing the long-term cumulative return through a Q-learning mechanism. Furthermore, it explicitly incorporates a safety constraint based on the Conditional Value at Risk (CVaR) to proactively avoid hazardous actions. Simulation results demonstrate that the proposed SDQ algorithm outperforms several mainstream baseline methods in terms of navigation efficiency, obstacle avoidance safety, and mission success rate. Additionally, in tests involving time-varying ocean current disturbances, SDQ exhibits notable robustness.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"349 ","pages":"Article 124215"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928482","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 : 2026-01-09DOI: 10.1016/j.oceaneng.2026.124182
Chao Liu , Tong Dong , Sui Wang , Shilei Pan , Liang Kong
In complex marine environments, calcareous sand exhibits significant stress direction dependence. However, the coupling effects of inherent anisotropy and stress-induced anisotropy on the calcareous sand have been rarely investigated. This study indirectly achieved rotation of the principal stress around the σ3-axis (i.e., the bedding direction angle α3) through an advanced specimen preparation method, while employing the Hollow Cylindrical Apparatus (HCA) to rotate the principal stress around the σ2-axis (i.e., the principal stress direction α2). On this basis, a series of biaxial monotonic rotation of principal stress (BMRPS) tests were conducted on calcareous sand. The results show that stress-induced anisotropy is the primary factor influencing the mechanical properties of calcareous sand. The stress-strain relationship is interactively influenced by α2 and α3, with strain hardening being weakest at α2 = 67.5° and α3 = 0°. The maximum and minimum failure strengths qf occur at α2 = 0°, α3 = 22.5° and α2 = 67.5°, α3 = 67.5°, respectively. Meanwhile, the shape and dip angle of shear bands depend on α2. Furthermore, the stress direction dependence of calcareous sand was compared with that of siliceous sand using the anisotropy degree η, and a predictive formula for the anisotropy of calcareous sand was established.
{"title":"Stress-strain relationship and stress direction dependence of calcareous sand under biaxial monotonic rotation of principal stress","authors":"Chao Liu , Tong Dong , Sui Wang , Shilei Pan , Liang Kong","doi":"10.1016/j.oceaneng.2026.124182","DOIUrl":"10.1016/j.oceaneng.2026.124182","url":null,"abstract":"<div><div>In complex marine environments, calcareous sand exhibits significant stress direction dependence. However, the coupling effects of inherent anisotropy and stress-induced anisotropy on the calcareous sand have been rarely investigated. This study indirectly achieved rotation of the principal stress around the <em>σ</em><sub>3</sub>-axis (i.e., the bedding direction angle <em>α</em><sub>3</sub>) through an advanced specimen preparation method, while employing the Hollow Cylindrical Apparatus (HCA) to rotate the principal stress around the <em>σ</em><sub>2</sub>-axis (i.e., the principal stress direction <em>α</em><sub>2</sub>). On this basis, a series of biaxial monotonic rotation of principal stress (BMRPS) tests were conducted on calcareous sand. The results show that stress-induced anisotropy is the primary factor influencing the mechanical properties of calcareous sand. The stress-strain relationship is interactively influenced by <em>α</em><sub>2</sub> and <em>α</em><sub>3</sub>, with strain hardening being weakest at <em>α</em><sub>2</sub> = 67.5° and <em>α</em><sub>3</sub> = 0°. The maximum and minimum failure strengths <em>q</em><sub>f</sub> occur at <em>α</em><sub>2</sub> = 0°, <em>α</em><sub>3</sub> = 22.5° and <em>α</em><sub>2</sub> = 67.5°, <em>α</em><sub>3</sub> = 67.5°, respectively. Meanwhile, the shape and dip angle of shear bands depend on <em>α</em><sub>2</sub>. Furthermore, the stress direction dependence of calcareous sand was compared with that of siliceous sand using the anisotropy degree <em>η</em>, and a predictive formula for the anisotropy of calcareous sand was established.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"349 ","pages":"Article 124182"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928574","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 : 2026-01-09DOI: 10.1016/j.oceaneng.2025.124084
Qais Shehadeh Khraisat , Martin Persson , Rickard E. Bensow
Concerns about shipping noise influence on marine life are motivating mitigation efforts, increasing interest in numerical methods for underwater radiated noise (URN) assessment. A common approach is to use incompressible flow solvers with the Ffowcs Williams-Hawkings (FW-H) method, though reliability is shown to depend on modelling choices.
To advance on this matter, model and full scale simulations are performed for a fully appended ship, operating in mildly cavitating conditions, using the incompressible Reynolds-averaged Navier–Stokes (RANS) framework to investigate pressure pulse and URN levels. Predictions are compared with model scale experiments and full scale sea trial measurements. The permeable FW-H method is used, while also an alternative approach modelling cavitation as a monopole source combined with the solid FW-H formulation and corrections for Lloyd’s mirror effect is proposed and tested.
Further, the effect of blockage on cavitation is investigated and found to affect induced pressure pulse and URN levels due to effects on the ship wakefield in the tunnel section. Although good agreement is found for cavity dynamics and pressure pulses, significant discrepancies are found in URN levels between measurements and numerical predictions, for both methods. Reasons for these differences are partly understood and discussed, while other questions remain open.
对船舶噪声对海洋生物影响的关注正在推动缓解努力，增加了对水下辐射噪声（URN）评估数值方法的兴趣。一种常见的方法是使用Ffowcs williams - hawkins （FW-H）方法求解不可压缩流，尽管可靠性取决于建模选择。为了进一步研究这一问题，对一艘在轻度空化条件下运行的全附加船进行了模型和全尺寸模拟，使用不可压缩reynolds -average Navier-Stokes （RANS）框架来研究压力脉冲和URN水平。预报结果与模型尺度试验和全尺度海上试验测量结果进行了比较。本文采用了可渗透的FW-H方法，并结合固体FW-H公式和劳氏镜效应的修正，提出了一种将空化建模为单极源的替代方法，并进行了测试。进一步，研究了阻塞对空化的影响，发现由于对隧道段船舶尾流场的影响，会影响诱导压力脉冲和URN水平。虽然在空腔动力学和压力脉冲上发现了很好的一致性，但在两种方法的测量和数值预测之间发现了显著的URN水平差异。造成这些差异的原因已被部分理解和讨论，而其他问题仍未解决。
{"title":"Cavitation underwater radiated noise methodology applied to a propeller operating in-behind condition","authors":"Qais Shehadeh Khraisat , Martin Persson , Rickard E. Bensow","doi":"10.1016/j.oceaneng.2025.124084","DOIUrl":"10.1016/j.oceaneng.2025.124084","url":null,"abstract":"<div><div>Concerns about shipping noise influence on marine life are motivating mitigation efforts, increasing interest in numerical methods for underwater radiated noise (URN) assessment. A common approach is to use incompressible flow solvers with the Ffowcs Williams-Hawkings (FW-H) method, though reliability is shown to depend on modelling choices.</div><div>To advance on this matter, model and full scale simulations are performed for a fully appended ship, operating in mildly cavitating conditions, using the incompressible Reynolds-averaged Navier–Stokes (RANS) framework to investigate pressure pulse and URN levels. Predictions are compared with model scale experiments and full scale sea trial measurements. The permeable FW-H method is used, while also an alternative approach modelling cavitation as a monopole source combined with the solid FW-H formulation and corrections for Lloyd’s mirror effect is proposed and tested.</div><div>Further, the effect of blockage on cavitation is investigated and found to affect induced pressure pulse and URN levels due to effects on the ship wakefield in the tunnel section. Although good agreement is found for cavity dynamics and pressure pulses, significant discrepancies are found in URN levels between measurements and numerical predictions, for both methods. Reasons for these differences are partly understood and discussed, while other questions remain open.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"349 ","pages":"Article 124084"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928485","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 : 2026-01-09DOI: 10.1016/j.oceaneng.2026.124245
Wenkai Tan , Yujie Liu , Fapeng Zhang , Qing Li , Zehua Xu , Anling Li , Qiang He
Trans-medium vehicles must achieve efficient propulsion and drag reduction in both air and water, in which large density and Reynolds number disparities pose persistent bottlenecks. We introduce biomimetic leading-edge tubercles and conduct coupled experiments and simulations across the two media. Using NACA 63(4)-021 as the baseline, three propellers were designed: 0 % (P0), 2.5 % (P2.5), and 5 % (P5) tubercle amplitudes. A water towing tank and an air towing facility provided open-water/open-air performance measurements, and STAR-CCM + MRF–RANS simulations resolved the flow fields. P2.5 delivered the best overall performance. In water at J = 0.9, thrust increased by 8.2 % relative to P0 and efficiency rose by 6.8 %; in air at J = 1.0, efficiency improved by 11.6 %, with torque notably reduced at high J. A moderate tubercled leading edge reduces the negative-pressure peak on suction side and segments the low-pressure band, thereby increasing the cavitation inception margin. It promotes redistribution of the wake from a centerline jet toward a broader radial extent, alleviating losses associated with high shear and vortex cores. These results show that a moderate tubercle amplitude can simultaneously reduce drag and enhance efficiency in both media, underscoring the engineering promise of biomimetic tubercled propulsors for trans-medium applications.
{"title":"Experimental and numerical simulation study on drag reduction performance of cross-medium bionic leading-edge propellers","authors":"Wenkai Tan , Yujie Liu , Fapeng Zhang , Qing Li , Zehua Xu , Anling Li , Qiang He","doi":"10.1016/j.oceaneng.2026.124245","DOIUrl":"10.1016/j.oceaneng.2026.124245","url":null,"abstract":"<div><div>Trans-medium vehicles must achieve efficient propulsion and drag reduction in both air and water, in which large density and Reynolds number disparities pose persistent bottlenecks. We introduce biomimetic leading-edge tubercles and conduct coupled experiments and simulations across the two media. Using NACA 63(4)-021 as the baseline, three propellers were designed: 0 % (P0), 2.5 % (P2.5), and 5 % (P5) tubercle amplitudes. A water towing tank and an air towing facility provided open-water/open-air performance measurements, and STAR-CCM + MRF–RANS simulations resolved the flow fields. P2.5 delivered the best overall performance. In water at J = 0.9, thrust increased by 8.2 % relative to P0 and efficiency rose by 6.8 %; in air at J = 1.0, efficiency improved by 11.6 %, with torque notably reduced at high J. A moderate tubercled leading edge reduces the negative-pressure peak on suction side and segments the low-pressure band, thereby increasing the cavitation inception margin. It promotes redistribution of the wake from a centerline jet toward a broader radial extent, alleviating losses associated with high shear and vortex cores. These results show that a moderate tubercle amplitude can simultaneously reduce drag and enhance efficiency in both media, underscoring the engineering promise of biomimetic tubercled propulsors for trans-medium applications.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"349 ","pages":"Article 124245"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928483","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 : 2026-01-09DOI: 10.1016/j.oceaneng.2026.124207
Yue Lu , Weixin Kang , Kun Liu , Zili Wang , C. Guedes Soares
This study experimentally and numerically investigates the damage characteristics of AA6061-T6 aluminium stiffened plates subjected to impact loading. Both quasi-static and drop-weight impact tests are performed on stiffened plates, and the impact positions are designed in the vicinity of the weld seam to reveal the damage characteristics of weld-induced softening zones. Structural responses under different impact velocities are analysed and compared, and the dynamic effects are assessed through an analysis of impact force responses and damage shapes. Numerical simulations are then carried out, incorporating anisotropic mechanical properties, strain rate effects, and welding-induced softening in the material modelling. The results indicate that both strain rate effects and material anisotropy have only a limited influence on the global impact responses and damage characteristics of the investigated aluminium stiffened plates. In contrast, detailed weld softening modelling significantly improves the accuracy of numerical predictions when impact occurs near the weld seam, whereas the one-inch rule approach may lead to notable inaccuracies. The findings provide insight into impact-induced damage mechanisms in welded aluminium structures and offer guidance for the reliable assessment and design of aluminium alloy ship structures.
{"title":"Impact responses of aluminium stiffened plates near weld seams under quasi-static and dynamic loading","authors":"Yue Lu , Weixin Kang , Kun Liu , Zili Wang , C. Guedes Soares","doi":"10.1016/j.oceaneng.2026.124207","DOIUrl":"10.1016/j.oceaneng.2026.124207","url":null,"abstract":"<div><div>This study experimentally and numerically investigates the damage characteristics of AA6061-T6 aluminium stiffened plates subjected to impact loading. Both quasi-static and drop-weight impact tests are performed on stiffened plates, and the impact positions are designed in the vicinity of the weld seam to reveal the damage characteristics of weld-induced softening zones. Structural responses under different impact velocities are analysed and compared, and the dynamic effects are assessed through an analysis of impact force responses and damage shapes. Numerical simulations are then carried out, incorporating anisotropic mechanical properties, strain rate effects, and welding-induced softening in the material modelling. The results indicate that both strain rate effects and material anisotropy have only a limited influence on the global impact responses and damage characteristics of the investigated aluminium stiffened plates. In contrast, detailed weld softening modelling significantly improves the accuracy of numerical predictions when impact occurs near the weld seam, whereas the one-inch rule approach may lead to notable inaccuracies. The findings provide insight into impact-induced damage mechanisms in welded aluminium structures and offer guidance for the reliable assessment and design of aluminium alloy ship structures.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"349 ","pages":"Article 124207"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928484","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 : 2026-01-09DOI: 10.1016/j.oceaneng.2026.124236
Lisong Zhang , Lijie Shan , Xinfeng Pang
An elastoplastic analytical model was developed to investigate the stress–strain behavior of buried pipelines crossing strike–slip faults. The mechanical response of pipelines was divided into the transverse bending (governed by bending moments) and the axial elongation (driven by tensile forces). The transverse bending was analyzed by two approaches: beam–on–elastic–foundation differential equations for low–curvature segments, and elastoplastic–beam differential equations for high–curvature segments. The latter incorporated the axial tensile force as the coupling parameter between the transverse bending and the axial elongation. Furthermore, the axial elongation was solved by the equation of equilibrium and the compatibility of displacements, accounting for both nonlinear pipe–soil interaction and material plasticity of the pipeline steel. In addition, due to the coupling between the transverse bending and the axial elongation during solutions, it was proposed with the solution procedure to calculate bending stresses in plastic segments of pipelines. The total stress was subsequently derived by combining various scenarios of bending and axial stresses, including: (1) bending and axial stresses simultaneous exceeding yield strength, and (2) only one exceeding the yield strength while the other not exceeding. Model validation was performed through comparisons with finite–element simulations across different parameter spaces, such as various fault displacements, D/t ratios, burial depth ratios. Results demonstrated that the proposed analytical model provided reliable stress–strain predictions, with only minor deviations of ≤8.18 %. Finally, the parametric analyses were carried out to investigate effects of pipeline crossing angles, pipe–soil friction coefficients and buried depth on the maximum total strain.
{"title":"An elastoplastic analytical model of stress–strain analysis of buried pipelines under strike–slip faults","authors":"Lisong Zhang , Lijie Shan , Xinfeng Pang","doi":"10.1016/j.oceaneng.2026.124236","DOIUrl":"10.1016/j.oceaneng.2026.124236","url":null,"abstract":"<div><div>An elastoplastic analytical model was developed to investigate the stress–strain behavior of buried pipelines crossing strike–slip faults. The mechanical response of pipelines was divided into the transverse bending (governed by bending moments) and the axial elongation (driven by tensile forces). The transverse bending was analyzed by two approaches: beam–on–elastic–foundation differential equations for low–curvature segments, and elastoplastic–beam differential equations for high–curvature segments. The latter incorporated the axial tensile force as the coupling parameter between the transverse bending and the axial elongation. Furthermore, the axial elongation was solved by the equation of equilibrium and the compatibility of displacements, accounting for both nonlinear pipe–soil interaction and material plasticity of the pipeline steel. In addition, due to the coupling between the transverse bending and the axial elongation during solutions, it was proposed with the solution procedure to calculate bending stresses in plastic segments of pipelines. The total stress was subsequently derived by combining various scenarios of bending and axial stresses, including: (1) bending and axial stresses simultaneous exceeding yield strength, and (2) only one exceeding the yield strength while the other not exceeding. Model validation was performed through comparisons with finite–element simulations across different parameter spaces, such as various fault displacements, <em>D</em>/<em>t</em> ratios, burial depth ratios. Results demonstrated that the proposed analytical model provided reliable stress–strain predictions, with only minor deviations of ≤8.18 %. Finally, the parametric analyses were carried out to investigate effects of pipeline crossing angles, pipe–soil friction coefficients and buried depth on the maximum total strain.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"349 ","pages":"Article 124236"},"PeriodicalIF":5.5,"publicationDate":"2026-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928573","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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