Ocean Engineering最新文献

{"title":"Investigation of subcritical flow regime and force characteristics of square cylinder with various corner modification techniques","authors":"Jinyang Liu ,&nbsp;Yonglian Chang ,&nbsp;Yi Hui ,&nbsp;Qingshan Yang ,&nbsp;Xin Guan ,&nbsp;Liang Xu","doi":"10.1016/j.oceaneng.2025.121310","DOIUrl":"10.1016/j.oceaneng.2025.121310","url":null,"abstract":"<div><div>Corner modifications are effective strategies for mitigating flow-induced forces and vibrations, thereby ensuring structural safety in ocean engineering. However, the flow mechanism associated with these modifications for subcritical Reynolds flow remain inadequately understood. This study employs large eddy simulation (LES) to evaluate the flow structure and fluid-induced forces of a square cylinder with different corner modifications, including rounded, chamfered, step cut corner, and corner ribs, at a Reynolds number of <em>R</em>_<em>e</em> = 2.2 × 10⁴. The results indicate that both front and four corner modifications notably alter flow structures and flow stability, characterized by elongated wake vortices and less vigorous flapping of the shear layer. For rounded and chamfered corners, the models with front and four corner modifications exhibit similar flow behaviors and force characteristics. However, for step cut corners and corner ribs, modifications to the rear corners further modify the flow structure compared with those addressing only the front corners. The four step cut corners and corner ribs can induce local recirculation inside the modified corners, which is critical in modifying the flow topology, shear layer behavior, pressure distribution, and resultant forces. The study concludes that front step cut and four corner ribs are optimal strategies for flow control, achieving force reduction ratios of 38.3 % for drag <span><math><mrow><msub><mover><mi>C</mi><mo>‾</mo></mover><mi>d</mi></msub></mrow></math></span> and 84.3 % for lift <em>C'</em>_<em>l</em> in the model with four corner ribs. Furthermore, the rib significantly influences the wake vortex and force characteristics, with deeper ribs improving flow dynamics, reducing vortex intensity, and lowering wall pressure and fluid-induced forces. These findings offer valuable insights for the design and implementation of flow control methods in ocean engineering.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"331 ","pages":"Article 121310"},"PeriodicalIF":4.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865125","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":"Rescue plan of unmanned life-saving vehicle in multi-obstacle waters under multi-strategy innovative ant colony optimization strategy","authors":"Zhilei Liu,&nbsp;Jiaoyi Hou,&nbsp;Dayong Ning,&nbsp;Fengrui Zhang,&nbsp;Gangda Liang","doi":"10.1016/j.oceaneng.2025.121242","DOIUrl":"10.1016/j.oceaneng.2025.121242","url":null,"abstract":"<div><div>To improve the rescue efficiency of the jet propulsion unmanned life-saving vehicles (ULSVs), a novel rescue plan based on improved Ant Colony Optimization (ACO) for multiple ULSVs in multi-obstacle environments is proposed in this research. In the proposed approach, an unevenly initialized pheromone matrix is first employed to help the ant colony search a larger space and maintain population diversity. Secondly, considering the issues of poor search efficiency and accuracy in traditional ACO, this study introduces a position update strategy based on exponential approximation and dynamic tracking of optimal values. Meanwhile, a grid partitioning method based on local grid refinement is designed to further enhance the quality of the planned paths and ensure safety. Finally, a dynamic adaptive optimization mechanism is proposed to endow the ACO with the path planning ability in dynamic environments, enabling it to quickly adapt when the environment changes. In the experimental stage, a large number of simulation experiments and practical tests are carried out, and real-world maps and ocean current data are selected to validate the proposed strategy. The results show that the rescue system can plan paths that best meet actual needs and offer higher safety and reliability compared to other algorithms.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"331 ","pages":"Article 121242"},"PeriodicalIF":4.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865146","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":"Constraint effects on the hydroelasticity of very large floating structures","authors":"Guiyong Zhang ,&nbsp;Qiankun Li ,&nbsp;Changqing Jiang ,&nbsp;Ould el Moctar ,&nbsp;Zhe Sun","doi":"10.1016/j.oceaneng.2025.121304","DOIUrl":"10.1016/j.oceaneng.2025.121304","url":null,"abstract":"<div><div>Offshore structures are continuously subjected to wave-induced loads, resulting in both rigid-body motion and elastic deformation. In very large floating structures (VLFSs), hydroelastic deformation is primarily characterized by vertical displacement, encompassing both oscillatory motion and flexible deflection. Hydroelastic analysis typically involves imposing constraints to restrict body motion in waves, which can significantly influence deformation behavior. To assess the impact of these constraints, this study examines how different boundary conditions affect the hydroelastic response of VLFSs. Specifically, five test cases with distinct constraint conditions are designed to systematically evaluate their effects across multiple wavelengths. A coupled numerical methodology integrating computational fluid dynamics (CFD) and computational structural dynamics (CSD) is developed to analyze hydroelastic deformation under these conditions. Strain distributions at key locations along the floating structure are examined under varying wave conditions. Results indicate that spring constraints provide a stable deformation pattern, aligning well with physical expectations in both long and short waves. This study highlights the critical role of constraint selection in VLFS modeling and suggests that future research should explore multi-directional wave effects and diverse restraint configurations to enhance VLFS design and performance.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"331 ","pages":"Article 121304"},"PeriodicalIF":4.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859677","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":"Investigation of coupled motion and power generation characteristics in a star-CCM-based floating wind-wave-current power generation platform","authors":"Yulong Chen ,&nbsp;Dan Yu ,&nbsp;Yupeng Duan ,&nbsp;Jian Zhang ,&nbsp;Lixue Jiang","doi":"10.1016/j.oceaneng.2025.121255","DOIUrl":"10.1016/j.oceaneng.2025.121255","url":null,"abstract":"<div><div>This study introduces a Floating Wind Wave Current-Power Generation Platform (FWWC-PGP) designed to integrate wind, wave, and tidal energies for electricity production. Through simulations using Star-CCM software, the research examines the platform's coupled motion responses and power generation characteristics under varying wind, wave, and current conditions, specifically analyzing the interactions between the wind turbine, wave energy floaters, and water turbines. The findings indicate that wave periods and the loading on the water turbines significantly influence the platform's motion, whereas the thrust generated by the wind turbines has a comparatively minor effect. Across all operating conditions, wind turbines are the primary source of power generation, with water turbines and moonpool-type floaters contributing comparatively less. At lower wind speeds, the wave energy devices of the moonpool-type floaters deliver substantial power supplementation, while the water turbines ensure stable electricity generation, thereby enhancing the system's adaptability to environmental variations. This study offers innovative approaches to enhancing the utilization efficiency of marine natural resources and holds significant practical implications for the development and exploitation of marine renewable energy.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"331 ","pages":"Article 121255"},"PeriodicalIF":4.6,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859681","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":"Wave transmission of deep-draft box-type bottom-detached breakwaters","authors":"Zihan Liu ,&nbsp;Nils Goseberg ,&nbsp;Lorenzo Cappietti","doi":"10.1016/j.oceaneng.2025.121208","DOIUrl":"10.1016/j.oceaneng.2025.121208","url":null,"abstract":"<div><div>Expanding human activity into offshore marine areas presents significant challenges. Protecting offshore structures and the areas within them from the destructive forces of large waves is of primary importance. Bottom-founded breakwaters are effective in shallow waters, whereas floating or bottom-detached breakwaters are more suitable for deeper waters. This study explored the transmission coefficient (<em>k</em>_<em>t</em>) of fixed box-type bottom-detached breakwaters (BDBs) with various dimensions under different wave conditions. A numerical wave flume based on Computational Fluid Dynamics (CFD) was validated using experimental measurements from a physical wave flume and employed to conduct a parametric study. The results indicated that the changes in wave steepness had a small effect on <em>k</em>_<em>t</em> of BDBs, while significant decreases in <em>k</em>_<em>t</em> were observed with the increase in relative draft (<em>D</em>_<em>FB</em><em>/L</em>_<em>w</em>) and relative width (<em>W</em>_<em>FB</em><em>/L</em>_<em>w</em>), where <em>L</em>_<em>w</em> presents wavelength. A predictive equation for <em>k</em>_<em>t</em> was derived from the numerical results and validated using the numerical data and the experimental data from present and previous studies. Within <em>W</em>_<em>FB</em><em>/L</em>_<em>w</em><em>=</em>0.004–0.43 and <em>D</em>_<em>FB</em><em>/L</em>_<em>w</em> = 0.001–0.21, the proposed equation demonstrated considerable accuracy with a relative error within the range of (−20 %, 20 %). The Root Mean Square Errors (<em>RMSEs</em>) of the <em>k</em>_<em>t</em> predicted by the proposed equation and various experimental datasets were below 0.1.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"331 ","pages":"Article 121208"},"PeriodicalIF":4.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859674","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":"Knowledge extraction from decision-making data for maritime navigation support","authors":"Weiwei Tian,&nbsp;Beatriz Sanguino,&nbsp;Mingda Zhu,&nbsp;Øivind Kåre Kjerstad,&nbsp;Guoyuan Li,&nbsp;Houxiang Zhang","doi":"10.1016/j.oceaneng.2025.121268","DOIUrl":"10.1016/j.oceaneng.2025.121268","url":null,"abstract":"<div><div>As maritime traffic density increases, providing navigation support for enhanced situational awareness and decision-making becomes critical. Extracting expert knowledge is challenging due to its subjective nature, and analyzing raw maritime data is often inefficient due to the overwhelming volume of non-critical information. This work proposes extracting decision-making process knowledge from Automatic Identification System (AIS) data to assist in navigation support. This approach balances the subjectivity of historical navigational decision information and mines critical information from raw traffic data. Specifically, decision-making point data categorized by maneuver type is collected from raw AIS data, followed by statistical analysis in terms of risk indicators and positional information. This analysis facilitates knowledge extraction, which is then applied to develop a rule-based decision-making algorithm. To validate this algorithm, a decision support system is designed in a professional navigation simulator and tested in a challenging encounter scenario by 12 participants with a nautical science background. The results indicate that the developed decision support system effectively provides early warnings for decision-making.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"331 ","pages":"Article 121268"},"PeriodicalIF":4.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854639","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":"Influence of the longitudinal spacing on a two-unit tandem tidal turbine arrangement in turbulent flow","authors":"Yuquan Zhang ,&nbsp;Junhui Xu ,&nbsp;Zhiqiang Liu ,&nbsp;Emmanuel Fernandez-Rodriguez","doi":"10.1016/j.oceaneng.2025.121320","DOIUrl":"10.1016/j.oceaneng.2025.121320","url":null,"abstract":"<div><div>The performance and interactions of turbines within tidal energy arrays are critical to optimizing power generation and minimizing environmental impact. This study experimentally investigates the performance and wake characteristics of a two-unit tandem tidal turbine arrangement under turbulent flow conditions, focusing on longitudinal spacings of 6D and 8D. Compared to a single turbine, the downstream turbine experiences significant power loss and operational limitations due to reduced inflow velocity and elevated turbulence intensity. These effects disrupt wake recovery and enhance energy exchange with the surrounding flow, particularly near the free surface. At optimal conditions, the power coefficient decreases from 0.343 for a single turbine to 0.189 and 0.234 for 6D and 8D longitudinal spacings, respectively. A validated superposition wake model demonstrates improved predictions in the far wake region, offering insights into array layout optimization. This work provides actionable guidance for designing efficient tidal turbine farms, with a specific emphasis on wake dynamics and inter-turbine spacing.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"331 ","pages":"Article 121320"},"PeriodicalIF":4.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854638","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":"Semi-analytical solution on three-layer liquid sloshing in the rectangular tank with bed topography","authors":"Zhanxue Cao ,&nbsp;Mi-An Xue ,&nbsp;Jinhai Zheng ,&nbsp;Xiaoli Yuan ,&nbsp;Yue Cheng ,&nbsp;Zhen Zhang","doi":"10.1016/j.oceaneng.2025.121247","DOIUrl":"10.1016/j.oceaneng.2025.121247","url":null,"abstract":"<div><div>A suitable topography is useful for reducing the impact pressure and lateral loads of the layered liquid sloshing on the structure, which improves its stability and durability. Effect of the bed topography on the layered liquid sloshing in tanks is investigated analytically. The complex liquid domain is naturally decomposed into three subdomains due to the incompatibility of the three types of liquids. The boundary condition between the first liquid layer and the topography is derived. The topography can be considered as a trigonometric function in this study. The formal solution of each sub-domain is derived analytically by applying the separation of variables method. The characteristic equations are determined by substituting the formal solution into the interface boundary conditions and topographic boundary conditions. The dynamic response equation under lateral excitation can be further established. The present method is proved to match well with two other calculation results. The semi-analytic results show that the topography can considerably reduce multilayer liquid sloshing.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"331 ","pages":"Article 121247"},"PeriodicalIF":4.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854640","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":"A rip-current prediction/forecast model employing likelihoods of rip currents beforehand simulated by a phase-resolving wave-current model","authors":"Junwoo Choi","doi":"10.1016/j.oceaneng.2025.121153","DOIUrl":"10.1016/j.oceaneng.2025.121153","url":null,"abstract":"<div><div>This article addressed a new rip-current prediction model by introducing its implementation to produce a sequence of rip-current risk index. The present risk index was evaluated by using the distributions of rip-current likelihoods varied according to wave and tidal properties. The likelihoods were derived from hundreds of in-advance numerical simulations using the phase-resolving wave-current model, FUNWAVE. The numerical simulations of rip currents were conducted with various wave and tidal conditions based on possible ocean scenarios at a specific coast. The risk index can be computed by inputting ocean observations or forecasts into a function combining the distributions of rip-current likelihoods. The performance of the rip current risk index using real-time observations was checked with event snapshots of the video-monitoring records during the summer of 2021 at the Haeundae coast. As a result, it was inferred that the rip-current risk index could support appropriate and useful warning signs at most of the time when significant rip currents occurred.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"331 ","pages":"Article 121153"},"PeriodicalIF":4.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854641","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":"Vibration reduction of floating offshore wind turbine with nonlinear vibration absorber: Concept, numerical analysis and experimental tests","authors":"Hang Zhang ,&nbsp;Binrong Wen ,&nbsp;Xinliang Tian ,&nbsp;Xiaofan Li ,&nbsp;Xin Li ,&nbsp;Zhike Peng","doi":"10.1016/j.oceaneng.2025.121196","DOIUrl":"10.1016/j.oceaneng.2025.121196","url":null,"abstract":"<div><div>Floating offshore wind turbines (FOWTs), as emerging energy systems, are subjected to environmental loads from winds, waves, and currents throughout their operational lifespan. Numerous strategies have been proposed to mitigate FOWT vibrations, aiming to enhance structural safety and stability. However, conventional linear vibration absorbers are often limited in their effectiveness, as they are typically designed for specific frequencies. In this paper, a nonlinear vibration absorber (NVA) is introduced, which achieves nonlinear stiffness through the orthogonal arrangement of springs. A numerical model of the FOWT equipped with the NVA is developed, and a semi-analytic technique is employed to reveal the targeted energy transfer (TET) and resonance capture cascading (RCC) phenomena occurring during the vibration reduction process, with the goal of achieving efficient mitigation performance and multi-modal vibration absorption. Additionally, an integrated FOWT-NVA wave basin test system is established, and extensive experiments are conducted under various offshore environments and absorber operating conditions. The results demonstrate that the NVA exhibits excellent vibration control performance and frequency robustness. Compared to conventional linear absorbers (such as tuned mass dampers, TMDs), the NVA significantly improves vibration reduction in both tower top responses and tower-base loads. This study validates the effectiveness of the NVA and provides a foundation for future experimental techniques and advanced controllers for FOWTs.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"331 ","pages":"Article 121196"},"PeriodicalIF":4.6,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143854637","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}