Ocean Engineering最新文献

{"title":"Experimental investigation on hydrodynamic performance of a helmholtz resonator-based floating breakwater array","authors":"Yuhang Zhang ,&nbsp;Jin Xu ,&nbsp;Prakash Kar ,&nbsp;Dezhi Ning","doi":"10.1016/j.oceaneng.2025.121982","DOIUrl":"10.1016/j.oceaneng.2025.121982","url":null,"abstract":"<div><div>Addressing the limitations of traditional floating breakwaters in intermediate to long-period wave attenuation, this research experimentally investigated the hydrodynamic performance of a Helmholtz-type floating breakwater (FB) array. Bloch band theory was employed to predict resonant bands. The mechanism of Helmholtz resonance is explained. The influence of geometrical design parameters is also considered. It is found that Helmholtz resonance, unlike Bragg resonance, can occur in a single structure at a lower frequency, making it suitable for attenuating long waves. In addition, the band gaps derived from Bloch Band theory match well with the experimental results, accurately predicting the frequency ranges of Helmholtz resonance. When Helmholtz resonance is activated, the radiated waves produced inside the FB cavity interact with the incoming waves, leading to the dissipation of wave energy. The maximum dissipation coefficient is observed within the frequency range corresponding to Helmholtz resonance. Meanwhile, as the opening width decreases and the draft increases, the Helmholtz resonant frequency shifts toward lower frequencies, and the resonant intensity weakens. Increasing the number of models in the array enhances the resonant strength and improves wave attenuation performance, although the rate of improvement gradually diminishes. Moreover, combining models with the different opening widths and optimizing their arrangement sequence (i.e., placing models with larger openings at the front) can broaden the resonant frequency band and enhance the overall wave attenuation performance.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121982"},"PeriodicalIF":4.6,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144472434","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}

{"title":"Sine-PSO-RF-SHAP prediction gas-liquid two-phase flow patterns in pipelines","authors":"Wei Li ,&nbsp;Qianqian Liu ,&nbsp;Jinkui Feng ,&nbsp;Jin Deng ,&nbsp;Zhou Fang","doi":"10.1016/j.oceaneng.2025.121995","DOIUrl":"10.1016/j.oceaneng.2025.121995","url":null,"abstract":"<div><div>The identification of gas-liquid two-phase flow patterns in pipelines is of critical significance for industrial process safety and efficiency optimization. However, traditional methods face challenges of insufficient model generalization ability and lack of interpretability. This paper proposes a Sine-PSO-RF-SHAP ensemble model integrating two-stage Sine chaotic mapping, Particle Swarm Optimization (PSO), Random Forest (RF), and SHAP interpretability analysis. Through multi-scale feature analysis and chaos-enhanced parameter optimization strategy, it achieves high-precision prediction of flow pattern classification and mechanistic analysis. Validated by datasets containing gas-liquid combinations of different media and experimental data from complex pipelines such as U-shaped, Z-shaped, and vertical pipes, the model achieves a flow pattern identification accuracy of 94.4 % on the test set, with a single inference time as low as 35.81 ms, significantly outperforming traditional machine learning and deep learning methods. SHAP analysis quantitatively reveals the dominant influence of features such as Surface Gas Velocity and pipe Inclination Angle on flow pattern transition, providing interpretable decision support for industrial scenarios. This study provides a technical paradigm combining efficiency and interpretability for intelligent monitoring of gas-liquid two-phase flows.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121995"},"PeriodicalIF":4.6,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144472392","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}

{"title":"Predicting the lateral capacity of short step-tapered and straight piles in cohesionless soils using an FE-AI hybrid technique","authors":"Ahmed Elsawwaf,&nbsp;Hany El Naggar,&nbsp;Farrukh A. Choksi,&nbsp;Habib Amin","doi":"10.1016/j.oceaneng.2025.121941","DOIUrl":"10.1016/j.oceaneng.2025.121941","url":null,"abstract":"<div><div>Offshore pile foundations are frequently subjected to significant lateral loads, often requiring large-diameter piles. Step-tapered piles have emerged as a cost-effective alternative, offering enhanced lateral capacity with reduced material use. However, reliable and straightforward methods for estimating their lateral bearing capacity remain limited. This study presents a hybrid approach combining three-dimensional finite element (FE) modeling and multi-objective genetic algorithm-based evolutionary polynomial regression (EPR-MOGA) to predict the lateral capacity of short straight and step-tapered piles in cohesionless soils. A parametric study using PLAXIS 3D simulated 580 different pile cases under service-level lateral loads. The mechanisms governing the performance of step-tapered piles were examined and discussed. The FE simulation results were then used to train an artificial intelligence (AI)-based model that produces predictive equations, accurately replicating the FE outputs at a horizontal deflection of 12.5 mm while reducing computational time significantly. The study predictions were compared against the Broms' method, the Characteristic Load Method (CLM), and full-scale field test data. The developed equations account for key geometric and soil parameters, offering a practical and efficient tool for the preliminary design of laterally loaded short piles.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121941"},"PeriodicalIF":4.6,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144472436","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}

{"title":"Memory-based deep reinforcement learning for COLREGs-compliant obstacle avoidance in USV with limited environmental knowledge","authors":"Zhenhong Fan ,&nbsp;Defeng Wu ,&nbsp;Yuqin Li ,&nbsp;Zheng You ,&nbsp;Shangkun Zhong","doi":"10.1016/j.oceaneng.2025.121978","DOIUrl":"10.1016/j.oceaneng.2025.121978","url":null,"abstract":"<div><div>The deployment of collision avoidance algorithms for unmanned surface vehicles is often limited by their capabilities to perceive dynamic and unpredictable marine environments. Influenced by human memory mechanisms, a memory-based deep reinforcement learning (MDRL) algorithm is proposed in this study for autonomous collision avoidance given limited environmental knowledge. A memory space is established to archive historical navigation data, and gated recurrent units are used to integrate these data into short-term memory for network decision-making. Consequently, the algorithm substantially facilitates the optimization of short-term memory and immediate decision-making, further compensating for the deficiencies of immediate perceptual data, enabling precise evaluation of encounter scenarios and the development of avoidance strategies compliant with the Convention on the International Regulations for Preventing Collisions at Sea (COLREGs). Experimental results demonstrate that the MDRL algorithm significantly enhances the collision avoidance capabilities of USV with limited environmental knowledge while ensuring COLREGs compliance.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121978"},"PeriodicalIF":4.6,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144472387","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}

{"title":"Redefining fatigue predictions: A multi-sea state HPC framework for FOWTs","authors":"Prokopios Vlachogiannis ,&nbsp;Christophe Peyrard ,&nbsp;Ajit C. Pillai ,&nbsp;David Ingram ,&nbsp;Pierre Bousseau ,&nbsp;Maurizio Collu","doi":"10.1016/j.oceaneng.2025.121961","DOIUrl":"10.1016/j.oceaneng.2025.121961","url":null,"abstract":"<div><div>Offshore wind is essential in the global transition to Net Zero carbon emission goals. As the industry pushes into deeper waters, fixed offshore wind solutions are no longer viable, increasing the reliance on floating alternatives. During their operational lifespan of at least 25 years, floating wind turbines are exposed to stochastic winds, waves, currents and the non-linear coupled loads, making fatigue assessment critical in their design and maintenance planning. The industry standard approach is to group similar conditions together into bins, each with a corresponding probability of occurrence based on historical data. However, by assuming all bin members are equivalent, this binning approach results in a loss of information, leading to inaccuracies. Here we propose a more detailed approach, called <em>Numerical Prototype approach</em>, where every individual sea state is considered, produces in turn fatigue estimates expected to be closer to reality since less information is lost due to binning. This paper studies the UMaine VolturnUS-S semi-submersible platform with the IEA 15 MW turbine for with a modified tower for an Atlantic site on the west of France. For the turbine tower, the Numerical Prototype results indicate lower cumulative fatigue estimations by 24 % for the principal direction of fatigue than those calculated using the classical binning method, while for the mooring line fairleads fatigue estimations are up to 14 % lower. These findings suggest that a more discretised calculation and more detailed representation of met-ocean loads lead to lower fatigue predictions, revealing the conservative nature of existing industrial methods. The binning methods currently used in industry result in conservative designs with increased material use and increased costs of floating wind turbines. The present results indicate for the first time a detailed methodology for fatigue estimation that allows optimised designs to reduce structural weight with consequent savings in both installation and material costs. Although the proposed methodology is computationally expensive, the potential savings offer significant benefits for project developers.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121961"},"PeriodicalIF":4.6,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144472389","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}

{"title":"Research on mechanism of anti-icing of polar ships based on ultrasonic vibration","authors":"Shi Hua,&nbsp;Youxiang Wang,&nbsp;MengWei Ge,&nbsp;Jian Zhang","doi":"10.1016/j.oceaneng.2025.121994","DOIUrl":"10.1016/j.oceaneng.2025.121994","url":null,"abstract":"<div><div>At present, the methods for ship anti-icing and de-icing are relatively outdated, mainly relying on traditional mechanical de-icing and chemical de-icing. However, these methods are not only inefficient but also may cause damage to the surface of the ship and increase maintenance costs. Based on the mechanism of ultrasonic vibration de-icing, this paper designs and develops the JUST electro-absorption ultrasonic vibrator, and conducts an in-depth discussion on its application in de-icing technology for steel materials of polar ships. By combining the numerical simulation method with the anti-icing and de-icing experiments, a systematic study was conducted on the anti-icing and de-icing effect of the frozen body of the hull steel plate of polar ships. The research covers the simulation and experimental comparative analysis of the electro-absorption ultrasonic vibrator under 11 different working conditions, revealing the influence of key parameters such as the arrangement mode, quantity, vibration frequency and vibration power of the ultrasonic vibrator on performance indicators such as the vibration displacement of the ship's ice cover and the ice cracking time.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121994"},"PeriodicalIF":4.6,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144472432","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}

{"title":"Event-based multi-target enclosing control for multi-ASV systems under DoS attacks","authors":"Jiahui Zhang ,&nbsp;Kezhong Liu ,&nbsp;Yue Yang ,&nbsp;Tieshan Li ,&nbsp;Zehua Jia","doi":"10.1016/j.oceaneng.2025.121989","DOIUrl":"10.1016/j.oceaneng.2025.121989","url":null,"abstract":"<div><div>This paper investigates the issue of multi-target enclosing control for multi-ASV systems under periodic denial-of-service (DoS) attacks with limited energy. To be consistent with the actual task scenarios, the multi-ASV system is subjected to model uncertainties, unmeasured velocity state variables, limited power, mechanical wear, actuator saturation, and external disturbances in this paper. First, an NN-based state observer is designed to estimate the unmeasured velocity state variables based on the nonlinear function approximation by the radial basis function neural network (RBFNN). Next, an event-based sliding mode control protocol is proposed to mitigate the negative effects of DoS attacks launched by the targets. The multi-ASV system can achieve enclosing control while tracking the convex combination of the states of the targets. Besides, the energy consumption and mechanical wear are reduced by the designed dynamic event-triggered mechanism (DETM). In addition, a saturation function is utilized to restrict the control input. Finally, the stability of the closed-loop system is verified by Lyapunov analysis and simulation results.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121989"},"PeriodicalIF":4.6,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144480185","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}

{"title":"Effect of interior restraint plate on the axial resistance of open-ended pipe pile using centrifuge modeling","authors":"Yafei Tian ,&nbsp;Xuefei Wang ,&nbsp;Bo Li ,&nbsp;Deming Li ,&nbsp;Jiale Li","doi":"10.1016/j.oceaneng.2025.121953","DOIUrl":"10.1016/j.oceaneng.2025.121953","url":null,"abstract":"<div><div>Wind energy is a promising renewable resource with vast potential to provide a clean and sustainable global electricity supply. Although pipe pile with interior restraint plate (PPIRP) exhibits significant advantages in bearing performance over open-ended pipe pile (OEPP), comprehensive studies on their bearing characteristics remain limited. This study investigates the compressive and pullout behaviors of OEPP and PPIRP. The research comprises compressive and tensile centrifuge tests of one OEPP and three PPIRPs. Based on recorded load response and soil pressure data, the vertical bearing characteristics of pile foundations are analyzed. The results reveal that the inclusion of an interior restraint plate (IRP) enhances both the compressive bearing capacity and the unit area pullout capacity of OEPP. Furthermore, a soil pressure distribution model at the pile tip is proposed to elucidate the IRP working mechanism. The IRP does not increase the earth pressure near the center of the pile tip, but it enhances the distribution of earth pressure near the pile shaft. A simplified method for evaluating the pile vertical bearing capacity based on the external pullout friction is also proposed. The findings of this study provide valuable insights for optimizing the design and performance of pile foundations.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121953"},"PeriodicalIF":4.6,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144365734","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}

{"title":"Coupled-variable-based tracking control for state-constrained surface ships under external disturbance","authors":"Nan Jiang ,&nbsp;Zhongcai Zhang ,&nbsp;Yang Gao ,&nbsp;Yuqiang Wu","doi":"10.1016/j.oceaneng.2025.121894","DOIUrl":"10.1016/j.oceaneng.2025.121894","url":null,"abstract":"<div><div>This paper investigates the tracking control problem for surface ships subject to position and velocity tracking error constraints, and unknown environmental disturbance. To achieve this, a disturbance observer is designed to estimate and compensate for external disturbance. Furthermore, a coupled-variable constraint is introduced, in which an auxiliary error signal is constrained to simultaneously constrain both position and velocity tracking errors. Meanwhile, the relationship among these three variables is rigorously analyzed. And the pre-specified constraints can be satisfied as long as the barrier Lyapunov function (BLF) remains bounded. Compared with the methods based on BLFs or Nonlinear Mapping to constrain position and velocity tracking errors, the proposed strategy only employs a single constraint condition to simultaneously limit both errors. Moreover, this technique eliminates the need for recursive process and feasibility condition verification, thereby significantly simplifying the control design. The effectiveness of the proposed control algorithm is validated through simulations conducted on the CyberShip II model.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121894"},"PeriodicalIF":4.6,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144365850","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}

{"title":"Research on the braking and sealing performance of rubber cylinder in the new type of two-cylinder anchor sealing mechanism of intelligent pipeline sealing robot","authors":"Jiaqing Xu ,&nbsp;Yang Tang ,&nbsp;Minghai Zhou ,&nbsp;Guorong Wang ,&nbsp;Mingbo Wang ,&nbsp;Renshan Pang","doi":"10.1016/j.oceaneng.2025.121858","DOIUrl":"10.1016/j.oceaneng.2025.121858","url":null,"abstract":"<div><div>Based on the motion model and sealing mechanism of intelligent pipeline plugging robot, the finite element simulation model of braking and sealing mechanism of a new type of double-cylinder anchoring and sealing mechanism was established to determine the influence parameters of the rubber cylinder during braking and sealing stage, analyze the influence of parameter changes of the rubber cylinder joint Angle on the braking and sealing performance of intelligent pipeline plugging robot, and design and build the simulation experiment of braking and sealing process. The rationality and reliability of the design of the new double cylinder anchoring and sealing mechanism are further verified. The results showed that the Mises stress value of the 28° rubber cylinder was 1.296 MPa, and the Mises wall displacement was 9.732 mm during the braking stage, and the braking effect was the best. In the sealing stage, when the joint Angle was 28°, the Mises stress value was 17.42 MPa, the maximum contact stress was achieved, and the sealing effect was best. When the braking hydraulic thrust reaches 64.5 kN, the braking hydraulic cylinder thrust reaches 718.76 kN, and the axial displacement of the rubber cylinder reaches 58.64 mm, the 10 MPa oil and gas pressure can be effectively blocked.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"338 ","pages":"Article 121858"},"PeriodicalIF":4.6,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144365851","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}