Ocean Engineering最新文献

{"title":"Investigation of wave spectral climate at key location of the Northern South China sea using a novel modeling framework","authors":"Yuxiang Ma ,&nbsp;Junzheng Li ,&nbsp;Congfang Ai ,&nbsp;Wentao Zheng ,&nbsp;Lei Sun ,&nbsp;Botao Xie","doi":"10.1016/j.oceaneng.2025.121012","DOIUrl":"10.1016/j.oceaneng.2025.121012","url":null,"abstract":"<div><div>Wave spectral climate explains the complexity of local marine environments. The dynamic variations of dominating wave components hamper wave spectral climate analysis, necessitating a precise modeling of climatic wave spectra. In this study, wave spectral datasets are constructed using WavewatchIII for the key location of the Northern South China Sea (NSCS-K). By the improved watershed algorithm, the datasets were classified into five distinct spectral classes, namely wind systems (ClassI), swell systems (ClassII), wind and swell systems (ClassIII), two swell systems (ClassIV), and complex multipeak systems (ClassV). The transformational patterns of wave systems in NSCS-K are revealed using a Markov chain approach. The main spectral class data are modeled by spectrum models. It is found that ClassI (64.80 %) and ClassIII (20.37 %) are the dominant ones in NSCS-K. In addition to the intra-spectral transformations that exceed 85 % in each class, the transformation from ClassI to ClassIII and ClassII to ClassIV deserves to be noticed, with a proportion of 6.66 % and 9.65 %, respectively. The JONSWAP spectrum model provides the most optimal applicability for ClassI, with <em>γ</em> typically between 1.8 and 2.2. For ClassIII, the Ochi-Hubble spectrum model achieves an accurate representation with <em>λ</em>₁ mostly in 2.0–2.5 and <em>λ</em>₂ mostly in 1.5–2.0.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"327 ","pages":"Article 121012"},"PeriodicalIF":4.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685830","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":"Simplified modeling of floating offshore wind farms with shared mooring line configurations","authors":"Qi Pan,&nbsp;Wei Yu,&nbsp;Po Wen Cheng","doi":"10.1016/j.oceaneng.2025.121018","DOIUrl":"10.1016/j.oceaneng.2025.121018","url":null,"abstract":"<div><div>Rising capital expenses for floating wind farms are pushing back their deployments in deep seas. Shared moorings can provide more cost-effective solutions than conventional moorings by reducing material and installation costs. However, current tools are not practical for intensive dynamic simulations of floating wind farms with shared mooring designs, due to their high computational demands. To address this challenge, this paper presents a simplified modeling approach that integrates a low-order multi-body simulation module, a quasi-static mooring model, and a Gaussian-based wake model. The efficiency and prediction accuracy of this approach are verified against a higher-fidelity simulation tool, showing significant reductions in computational effort and strong agreement in predictions for power output, floater surge, and mooring force of a two-turbine floating array under various environmental conditions. This approach is further applied for fast analysis and evaluation of an improved shared mooring design. The findings demonstrate that this method can facilitate design, analysis and evaluation process for shared mooring configurations during the conceptual design phase, advancing the development of more cost-effective solutions for floating wind farms.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"327 ","pages":"Article 121018"},"PeriodicalIF":4.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clamping parameters in full-scale tidal turbine blade tests: A case study","authors":"Miguel A. Valdivia-Camacho ,&nbsp;Sergio Lopez Dubon ,&nbsp;Fergus Cuthill ,&nbsp;Marek J. Munko ,&nbsp;Edward D. McCarthy ,&nbsp;Parvez Alam ,&nbsp;Conchúr M. Ó Brádaigh","doi":"10.1016/j.oceaneng.2025.120722","DOIUrl":"10.1016/j.oceaneng.2025.120722","url":null,"abstract":"<div><div>Full-scale laboratory tests of composite tidal turbine blades follow standards adapted from the testing of much longer wind turbine blades. Due to the much higher density of seawater, when compared to air, the diameter of an equivalent-power marine tidal stream turbine is approximately 4 times less than that of a wind turbine. In this paper, relevant guidelines regarding load introduction points for testing of tidal blades are assessed for the first time, specifically, the dimensions of the exclusion zones surrounding these loading points, that are ordinarily excluded from structural analysis. The dimensions of these zones are determined as a function of the blade chord length at the loading saddle locations, and the relevant standards suggest an exclusion length of up to one chord length at both sides of the load introduction points along the blade length. This study appraises these boundaries via a full-scale composite tidal blade structural test at the FastBlade facility, using a saddle-hydraulic actuator system. Strain measurements and Digital Image Correlation (DIC) are used to quantify the local strain contributions from saddle to blade clamping, during both static and fatigue loading. We propose a reduction of the exclusion zone boundary length from 1 to 0.45 times the chord length, based on the experimental comparison of two clamping methods: a manual torque-wrench method and a hydraulic-pressure method. The saddle material was also assessed by comparing the structural performance of MDF and plywood during these blade tests, with plywood showing better characteristics for high blade design loads. Our analyses could be used to update current standards to better align with the unique characteristics of composite tidal turbine blades, to effectively minimise the number of structural tests required for blade certification.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"327 ","pages":"Article 120722"},"PeriodicalIF":4.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on intra-ply shear and inter-ply sliding behaviors in cryogenic composite hoses","authors":"Yunguang Cui ,&nbsp;Jia Yan ,&nbsp;Qiang Chen ,&nbsp;Zhanqing Liu ,&nbsp;Rubin Zhu ,&nbsp;Juanzi Li ,&nbsp;Zhanjun Wu","doi":"10.1016/j.oceaneng.2025.121003","DOIUrl":"10.1016/j.oceaneng.2025.121003","url":null,"abstract":"<div><div>Cryogenic composite hose is the key equipment for tandem offloading operation of Floating Liquefied Natural Gas (FLNG). During the tandem offloading, the harsh marine environment results in hulls motion responses and complex hose motion characteristics. And the interlayer mechanical properties of the hose are easily affected by the external environment. In this paper, the interlayer behavior under different conditions (cryogenic temperature, dry-wet condition, and normal pressure) were investigated. The results showed that the low temperatures had little effect on the shear and sliding properties, resulting from little effect on the surface friction behaviors of the tows under low-temperature environment. Besides, sliding behavior was more likely to occur in wet condition, which was mainly derived from the presence of a water film between the layers, thus reducing the coefficient of friction (COF). Additionally, the COF decreased first and then reached minimum value followed by a plateau with the increasing of the normal force. Considering the effects of the intra-ply shear behaviors of fabric and normal pressure, a friction model coupling shear and sliding behavior was proposed, which fitted well with the experimental data and provides a reference for future structural design, numerical simulation and life prediction of cryogenic composite hoses.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"327 ","pages":"Article 121003"},"PeriodicalIF":4.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686503","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":"Design, hydrodynamic analysis, and test of a manta ray-inspired soft wing for flapping wing propulsion of underwater gliders","authors":"Yudong Guo ,&nbsp;Yuting Li ,&nbsp;Xiao Yu ,&nbsp;Libing Han ,&nbsp;Wendong Niu ,&nbsp;Tongshuai Sun","doi":"10.1016/j.oceaneng.2025.120998","DOIUrl":"10.1016/j.oceaneng.2025.120998","url":null,"abstract":"<div><div>Mobuliform swimming of manta rays represents a unique propulsion that can potentially be applied to underwater gliders (UGs) to enhance their maneuverability while minimizing noise. Inspired by the flexible pectoral fins of manta rays, this paper proposes a novel form of integral soft wing made of silicone rubber driven by a rigid fin ray insert, instead of flexible skin supported by rigid skeleton, and designs a UG prototype with the proposed soft wings (hereinafter referred to as SWUG). The soft wings reproduce spanwise oscillation and chordwise wave in mobuliform swimming, both of which contribute to thrust generation. The fluid-structure interaction is considered to analyze how the soft wings' physical parameters affect the UGs' hydrodynamic characteristics. The optimal configurations for the airfoil, dihedral angle, and aspect ratio are determined for excellent gliding performance. Further, the kinematic-Computational Fluid Dynamics (CFD) coupling approach is applied to simulate the intricate unsteady flow field resulting from the controlled motion of the soft wings. The evolution of the flow field and the thrust generation mechanism are analyzed, and the influence of flapping kinematic parameters on thrust performance and vehicle maneuverability are determined. Finally, the prototypes of the soft wings and SWUG are constructed to measure thrust and test swimming performance. A single soft wing can generate a maximum thrust of 3.6 N, and the SWUG can reach a top speed of 0.52 m/s. Experimental results validate the simulation findings and demonstrate the effective enhancement of UGs’ maneuverability by the soft wings. This research also offers insights into motion performance improvement and bionic design for other underwater vehicles.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"327 ","pages":"Article 120998"},"PeriodicalIF":4.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686501","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":"Experimental and empirical study of wave attenuation by an immobile dry-type vegetative floating island","authors":"Yuan-Jyh Lan ,&nbsp;Chia-Hsuan She ,&nbsp;Cheuk Yin Fan ,&nbsp;Xiang-Lei Jui ,&nbsp;Jen-Yen Pai","doi":"10.1016/j.oceaneng.2025.121009","DOIUrl":"10.1016/j.oceaneng.2025.121009","url":null,"abstract":"<div><div>This paper presents a systematic experimental and empirical investigation of the wave-attenuation effects of a stationary, dry-type vegetative floating island. In the experimental study, data were collected to analyze the effects of immersion depths, spatial coverage, and compositions of the matrix medium of a dry-type vegetative floating island, along with changing wave conditions. These data were used to evaluate the effects of the floating islands on the non-dimensional coefficients for wave reflection, transmission, and energy dissipation. For the empirical modeling study, dimensional analysis identified the primary non-dimensional parameter groups affecting wave attenuation within the matrix medium of the vegetative floating island. Empirical functions were derived through regression curve fitting to express the relationships between key influencing parameters and to create an empirical model applicable to wave attenuation by dry-type vegetative floating island systems. Based on this empirical model, the effects of the material shape parameters of the matrix medium on wave reflection, transmission, and energy dissipation were examined, including the modifications and analysis of the non-dimensional material shape parameters of the matrix medium. In addition, an algorithm was proposed to account for the conservation of wave energy by modifying the empirical model coefficients for wave reflection, transmission, and energy dissipation.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"327 ","pages":"Article 121009"},"PeriodicalIF":4.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685816","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":"Fault-tolerance analysis and application of tripod parallel manipulator utilized in underwater vectored thruster","authors":"Dexin Jiang ,&nbsp;Zaojun Fang ,&nbsp;Tianjiang Zheng ,&nbsp;Kunpeng Yan ,&nbsp;Dongjie Wang ,&nbsp;Huamin Li ,&nbsp;Chi Zhang ,&nbsp;Guilin Yang","doi":"10.1016/j.oceaneng.2025.120992","DOIUrl":"10.1016/j.oceaneng.2025.120992","url":null,"abstract":"<div><div>Underwater vectored thrusters based on a parallel manipulator have shown a potential to improve the maneuverability of underwater equipment. Owing to the hazardous and remote working environment, it is necessary to promote the fault tolerance of underwater vectored thrusters. One effective method is to deploy redundant actuators. Under the prerequisite of achieving vectored thrust, the structure and the number of redundant actuators should be compact and minimum, respectively. Based on these considerations, the symmetrical tripod parallel manipulator with high stiffness is designed to vectorize the thrust and endow the thruster with fault-tolerant capability. This article delves into the fault-tolerant characteristics of the manipulator and presents the corresponding control methods. Firstly, to explicate the fault tolerance of the presented manipulator, the constraint screw theory is utilized to construct the mobility analysis procedure. The results demonstrate that the manipulator can naturally deal with arbitrary one actuator stuck. Thereafter, the fault-tolerant kinematics model of the manipulator is formulated. Furthermore, one fault-tolerant controller based on the constructed kinematics model is designed to cope with the stuck fault and inaccurate extension fault, which maximizes the structural advantages of the manipulator. Finally, experiments validate the proposed fault-tolerance analysis and the control method, respectively.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"327 ","pages":"Article 120992"},"PeriodicalIF":4.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686500","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 framework to assess the operational state of autonomous ships with multi-component degrading systems","authors":"Xiang-Yu Zhou ,&nbsp;Shiqi Jin ,&nbsp;Xiaohang Ren ,&nbsp;Xu Sun ,&nbsp;Xiangkun Meng ,&nbsp;Shengzheng Nie ,&nbsp;Wenjun Zhang","doi":"10.1016/j.oceaneng.2025.121000","DOIUrl":"10.1016/j.oceaneng.2025.121000","url":null,"abstract":"<div><div>Ensuring that the safety level of autonomous ships is at least equivalent to the expected level of conventionally operated ships is a prerequisite for their smooth introduction into practical operation. Once the autonomous ship deviates from its operational envelope, it will enter a predetermined fallback state and easily lead to accidents. The response mechanism governing the operational state transitions of safety-centric autonomous ships is generally underexplored. This paper aims to develop a novel framework for assessing the operational state of autonomous ships with multi-component degrading systems and predicting the time threshold necessary for effective response actions. Its novelties consist of (1) a novel model to analyze and quantify the operational state of system considering degraded components; (2) an extension of system state assumption from a binary “normal-failure” to multi-state; (3) the utilization of System-Theoretic Process Analysis method to generate a functional control structure facilitating multi-state system modeling; and (4) elucidation of the transition mechanism applicable to the operational state of autonomous ships. The results indicate that the operational state of hardware facilities is less stable than software subsystems under ongoing routine maintenance, and the remotely-controlled ship with crew onboard may deviate from its operational envelope after 189.8 days without implementing any maintenance strategies.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"327 ","pages":"Article 121000"},"PeriodicalIF":4.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685815","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 structural design method based on topology optimization and approximate model for the pressure hull of underwater gliders","authors":"Xinrui Shen ,&nbsp;Yongkang Zhou ,&nbsp;Wei Ma ,&nbsp;Peng Wang ,&nbsp;Shaoqiong Yang ,&nbsp;Gongbo Wang ,&nbsp;Long Zhao ,&nbsp;Ming Yang","doi":"10.1016/j.oceaneng.2025.121022","DOIUrl":"10.1016/j.oceaneng.2025.121022","url":null,"abstract":"<div><div>The underwater glider is one of the most promising autonomous underwater vehicles for long-term ocean observations, whose energy carrying capacity and energy consumption are directly affected by compressibility and mass of the pressure hull. Therefore, this study proposes a design method for the pressure hull of underwater gliders based on topology optimization and approximate model to further increase its compressibility and decrease the mass. Topology optimization design of the pressure hull is realized with the variable density method, and an approximate model of mass and other output responses of the hull is established by the response surface method, which is used to optimize design variables and thus obtain an optimal pressure hull. The proposed design method is applied to optimize the pressure hull of the Petrel-L glider, and verification tests are performed. According to the test results, the deformation of the optimal pressure hull is increased by 39.7 %, which can indirectly reduce the energy consumption of the buoyancy drive unit and improve endurance of Petrel-L. Meanwhile, the mass of the optimal hull is decreased by 12.8 %, increasing the loading capacity of the vehicle under the same pressure. The proposed design method also provides a promising direction for optimizing the pressure hulls of other underwater vehicles.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"327 ","pages":"Article 121022"},"PeriodicalIF":4.6,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143686490","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":"Large-scale wave basin experimental study on the spatio-temporal distribution of wave impact loads on a semi-submersible platform","authors":"Nianfan Zhang ,&nbsp;Longfei Xiao ,&nbsp;Qingping Zou ,&nbsp;Cathal Cummins","doi":"10.1016/j.oceaneng.2025.120991","DOIUrl":"10.1016/j.oceaneng.2025.120991","url":null,"abstract":"<div><div>In recent decades, wave impact has been a highly concerning issue due to its extremely destructive potential in rough sea states. Accurate predictions of local impact loads are critical for the safety and reliability of coastal and offshore structures. However, our understanding of this problem is hindered by strong nonlinearity and violent nature of wave impacts. Large-scale experiments with dense instrumentation were conducted in a 50 m by 40 m by 10 m deepwater offshore basin to investigate the characteristics of wave impact pressure and impulse on a semi-submersible platform, consisting of a deck box, columns, and pontoons, under irregular waves. The temporal and spatial variations of wave impact pressures and pressure impulses are quantified and compared under various irregular waves. The results show that the time series of impact pressure exhibits a quasi-exponential growth and decay around the peak. For the 100-year sea state, the column experiences more severe wave impacts, with the averaged peak impact pressure reaching up to 124.6 kPa and the averaged pressure impulse up to 35.2 kPa<span><math><mo>·</mo></math></span>s, significantly greater than those on the deck box. The increase in significant wave height and spectral peak period not only increases the magnitude of local impact loads, but also the elevation and extent of the impact region. The impact loads induced by irregular waves show greater vertical variations than horizontal variations, with the maximum Coefficient of Variation (COV) exceeding 1, and exhibit similar propagation characteristics to those by regular waves on the fixed structure. The wavelet analysis of impact pressure reveals that the frequency of oscillating pressure varies depending on the volume and state of the entrained air during wave breaking, with distinctive features of aeration impacts. The motion of the platform changes the location, extent, and angle of the wave impinging the structure, consequently affecting the local impact pressure, total impact duration, and resulting impulse. The proposed method is expected to be a powerful tool for experimentally evaluating the spatio-temporal distribution of wave impact loads on offshore structures. The outcome of this study provide guidance for the design of reliable semi-submersible platforms under extreme sea conditions.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"327 ","pages":"Article 120991"},"PeriodicalIF":4.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}