Ocean Engineering最新文献

{"title":"Implicit rigid tube model predictive control for underwater manipulators with adaptive sliding mode strategy","authors":"Jingming Xu,&nbsp;Weidong Liu,&nbsp;Le Li,&nbsp;Guanghao Yang,&nbsp;Liwei Guo","doi":"10.1016/j.oceaneng.2025.120682","DOIUrl":"10.1016/j.oceaneng.2025.120682","url":null,"abstract":"<div><div>This paper presents an innovative control scheme combining implicit rigid tube model predictive control (IRTMPC) with adaptive sliding mode control (ASMC) for the trajectory tracking of underwater manipulators, addressing the challenges posed by model uncertainties and external disturbances in underwater environment. The IRTMPC approach avoids the complexity of explicit set algebra operations by utilizing implicit minimal robust invariant set representations, enabling efficient computation suitable for high-dimensional systems. The auxiliary tube control law in IRTMPC is designed by discrete ASMC, reinforcing the system’s stability and precision. Meanwhile, the dynamic parameters of a newly designed underwater manipulator are identified using a least squares identification method based on the integral operator. Finally, the effectiveness of the proposed IRTMPC-ASMC scheme for controlling the underwater manipulator is validated through trajectory tracking control simulation and experiments.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"324 ","pages":"Article 120682"},"PeriodicalIF":4.6,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465331","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":"Vortex-induced vibration (VIV) fatigue damage characteristics of submarine multispan pipelines","authors":"Yan Lu ,&nbsp;Zhanxiang Liu ,&nbsp;Wanhai Xu ,&nbsp;Yexuan Ma","doi":"10.1016/j.oceaneng.2025.120666","DOIUrl":"10.1016/j.oceaneng.2025.120666","url":null,"abstract":"<div><div>In offshore engineering, the free-spanning phenomenon frequently occurs in submarine pipelines. Multiple free-span pipelines are usually susceptible to more severe vortex-induced vibration (VIV) because of interactive effects between adjacent spans, resulting in potential fatigue damage. However, little attention has been given to the VIV fatigue damage characteristics of multispan pipelines. In this work, considering the pipe‒sediment interaction, model experiments were carried out on multispan pipelines to investigate the VIV fatigue damage features of double-span and triple-span pipelines. The VIV fatigue damage of the pipeline models was calculated via the <em>S</em>–<em>N</em> curve method and the linear accumulative damage law. The effects of the span ratio, burial depth, and axial tension force on VIV fatigue characteristics were studied in terms of the fatigue damage distribution and maximum fatigue damage. The results indicated that neighboring interactions and pipe‒sediment interactions considerably influence VIV fatigue damage in multispan pipelines. The variation in the span ratio significantly affects the fatigue damage distribution of adjacent spans. As the length difference between adjacent-span pipelines increases, the fatigue damage of the longer span greatly intensifies. However, with increasing burial depth, the VIV of the pipeline model decreases, and the fatigue damage is alleviated because the boundary constraint is strengthened. The increasing axial tension force can also somewhat reduce the maximum fatigue damage. Additionally, the suppression effect of the three-start helical strake on the VIV fatigue features of a multispan pipeline was also experimentally studied. The coverage rate of the helical strakes had a pronounced effect on the suppression efficiency. A coverage rate of 75% can have a more effective VIV suppression effect, with the maximum suppression efficiency exceeding 90%.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"324 ","pages":"Article 120666"},"PeriodicalIF":4.6,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465317","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":"The influence of the modeling order on the predictable area of non-linear unidirectional ocean waves","authors":"Marco Klein ,&nbsp;Helene Lünser ,&nbsp;Moritz Hartmann ,&nbsp;Sören Ehlers ,&nbsp;Norbert Hoffmann ,&nbsp;Nicolas Desmars","doi":"10.1016/j.oceaneng.2025.120673","DOIUrl":"10.1016/j.oceaneng.2025.120673","url":null,"abstract":"<div><div>The influence of non-linear modeling of phase-resolved ocean wave fields on the extent of the accessible predictable area is investigated. Assuming that the ocean surface dynamics is known over a limited spatial domain, e.g. via radar backscatter reconstruction, the linear wave theory as well as the high-order spectral method with various orders of non-linearity are used to propagate the surface with different levels of physical fidelity. The prediction accuracy is quantified by comparing the predicted waves to a reference, i.e. a fully known wave field propagated with a high-fidelity wave model. By doing this, it is made possible to track the spatiotemporal evolution of the prediction accuracy and define the predictable area as the region over which the accuracy is higher than a threshold, here defined by a “surface similarity parameter” lower than 0.1. Different unidirectional wave field characteristics are studied, highlighting the effect of the wave steepness, water depth and wave energy spreading around the peak spectral frequency, all impacting significantly the prediction accuracy, thus the predictable area. It is shown that the extent of the predictable area is highly dependent on the order of the considered wave model, and that the third order generally leads to the largest reachable predictable area in all configurations.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"324 ","pages":"Article 120673"},"PeriodicalIF":4.6,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465332","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 and data-driven optimization of vortex-induced vibration for marine energy harvesting","authors":"Peng Xu ,&nbsp;Shanshan Jia ,&nbsp;Yuan Zhang ,&nbsp;Xin Li ,&nbsp;Changqing Jiang","doi":"10.1016/j.oceaneng.2025.120683","DOIUrl":"10.1016/j.oceaneng.2025.120683","url":null,"abstract":"<div><div>Marine current energy, particularly harnessed through vortex-induced vibration (VIV), offers a cost-effective method for renewable energy generation, especially in low-flow velocity environments. In practical applications, VIV harvester performance is influenced by a free surface, making its dynamic behavior challenging to predict, which differs from the extensively studied VIV phenomenon in an infinite water depth. In this study, we propose an alternative approach to predict the optimal VIV working conditions using an artificial neural network (ANN). Physical model tests with varying parameters were conducted, and an ANN algorithm established a nonlinear mapping between these parameters and the energy conversion ratio. Utilizing the established ANN model, we identify the optimal combinations of working parameters that maximize the conversion ratio of the VIV. Experimental validation of the predicted optimal working conditions is conducted, and our predictions agree favorably with experimental measurements. Our results demonstrate that the neural network model, trained with the experimental data, exhibits high prediction accuracy and strong fitting ability. It offers a practical direction for optimizing VIV working parameters and predicting vibration performance at low flow velocities with a free surface, enhancing the potential for efficient marine current energy harvesting.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"324 ","pages":"Article 120683"},"PeriodicalIF":4.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465540","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":"Laboratory experiments on transforming emerged into submerged breakwaters","authors":"Nasrin Hassanpour ,&nbsp;Javier L. Lara ,&nbsp;Diego Vicinanza ,&nbsp;Pasquale Contestabile","doi":"10.1016/j.oceaneng.2025.120610","DOIUrl":"10.1016/j.oceaneng.2025.120610","url":null,"abstract":"<div><div>Traditional emerged breakwaters are frequently used to protect coastal regions from wave-induced damage. Although they are effective at mitigating transmitted wave energy, their advantages are not always evident, and they often have negative environmental impacts, such as seascape degradation, water stagnation, and unintended nearshore currents. In addition, most of these rigid structures around the world are nearing the end of their technical lifespan, consequently requiring significant financial investments for their refurbishment or removal. Sustainable management solutions and alternatives for their upgrading or removal are needed. In the current study, a novel approach to designing submerged breakwaters is introduced: the new submerged cross-section is obtained by reshaping the pre-existing emerged breakwater, i.e., maintaining the same volume and construction materials. The result is a constant-volume hydraulic analysis of different breakwater configurations under various wave climates, analysed through 2-D physical model tests conducted at the University of Campania “L. Vanvitelli” (IT). The comparison serves as a useful preliminary guideline for designers to choose the best solution based on specific wave climate conditions. The transmitted wave energy is analysed using spectral analysis, providing insight into the shape and peak frequency of the transmitted spectrum for each breakwater configuration. By considering the transmitted spectrum, designers can make informed decisions about the most effective shape for submerged breakwaters in different wave climates and to balance the compromise between improved water and sediment circulation patterns, panorama restoration and storm protection.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"324 ","pages":"Article 120610"},"PeriodicalIF":4.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454773","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":"Clustering observed nearshore wave groups in which rogue waves might arise","authors":"Xingjie Jiang ,&nbsp;Daolong Wang ,&nbsp;Qiang Lian ,&nbsp;Dalu Gao ,&nbsp;Xinmei Cui ,&nbsp;Zeyu Wang ,&nbsp;Yongzeng Yang","doi":"10.1016/j.oceaneng.2025.120658","DOIUrl":"10.1016/j.oceaneng.2025.120658","url":null,"abstract":"<div><div>Given that pronounced waves or crests might occur within similar wave group patterns as rogue waves, and have similar formation mechanisms in similar wave environments, this study sought to identify typical wave group configurations prone to form rogue waves from a multitude of observed crest- or wave-height-marked wave groups. On the basis of nine specifically defined wave group characteristic parameters, the Self-Organizing Map technique was used to cluster the selected samples, following which four wave group types with notably higher possibility of producing large crest or wave heights were identified. It was found that large crest and wave heights can be related to wave groups with multiple contributive constituents and one principal component, respectively; the former frequently occur as solitary waves but the latter generally appear in a sequence of large waves. Furthermore, pronounced crests might be more closely related to second-order nonlinearities, while marked wave heights could be associated with both second- and third-order nonlinearities, as well as surface currents travelling in opposite direction to waves. Interestingly, wave groups supposed to have greater chance of producing prominent crests are also more predisposed to exhibit deep wave troughs with flatter crests.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"324 ","pages":"Article 120658"},"PeriodicalIF":4.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454205","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":"Impact of vortex structures on fish hydrodynamics and fluid environment response analysis","authors":"Yiyun Peng,&nbsp;Min Chen,&nbsp;RuiDong An,&nbsp;Jia Li","doi":"10.1016/j.oceaneng.2025.120620","DOIUrl":"10.1016/j.oceaneng.2025.120620","url":null,"abstract":"<div><div>This study systematically investigates the hydrodynamic characteristics of <em>Coreius guichenoti</em>. The analysis focuses on the vorticity field, turbulent kinetic energy, flow field, and forces acting on the fish. By examining these factors, the study provides in-depth insights into the impact of vortex structures on the fish's dynamics. The findings indicate that an increase in the head yaw angle affects the asymmetry of the leading-edge vortex. This intensifies lift force fluctuations and impacts the fish's transverse stability. Similarly, an increase in the tail yaw angle adds complexity to the trailing-edge vortex and the tail vortex ring. As a result, drag on the fish increases. The fish's tolerance to vortex scale lies within the range where the ratio of turbulent integral length scale relative to fish length (<span><math><mrow><msub><mi>L</mi><mi>u</mi></msub><mo>/</mo><msub><mi>L</mi><mrow><mi>f</mi><mi>i</mi><mi>s</mi><mi>h</mi></mrow></msub></mrow></math></span>) is between zero and 65 percent. Beyond this threshold, force fluctuations rise considerably, especially at the tail, compromising stability. However, when 85%&lt; <span><math><mrow><msub><mi>L</mi><mi>u</mi></msub><mo>/</mo><msub><mi>L</mi><mrow><mi>f</mi><mi>i</mi><mi>s</mi><mi>h</mi></mrow></msub></mrow></math></span>, the fluctuation amplitude stabilizes, suggesting a saturation point where vortex scale effects become less significant. Additionally, high vortex shedding frequencies increase the force fluctuation frequency and reduce the fluctuation amplitude. This enhances the fish's posture stability. At the same time, it strengthens the vortex structure and turbulent kinetic energy around the fish. Although high-frequency vortex shedding can improve posture stability, it may reduce propulsion efficiency due to increased tail turbulence frequency. Conversely, low-frequency vortex shedding leads to larger force fluctuations and a more stable flow field, but it reduces posture stability, affecting both swimming direction control and propulsion efficiency. Consequently, protection measures for fish should carefully consider these factors to create suitable hydrodynamic conditions. This research provides valuable insights into fish swimming and foraging in complex flows, offering a scientific foundation for habitat protection and environmental restoration projects.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"324 ","pages":"Article 120620"},"PeriodicalIF":4.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454770","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":"Facilitating Multi-UAVs application for rescue in complex 3D sea wind offshore environment: A scalable Multi-UAVs collaborative path planning method based on improved coatis optimization algorithm","authors":"Hangyu Li ,&nbsp;Fahui Miao ,&nbsp;Xiaojun Mei","doi":"10.1016/j.oceaneng.2025.120701","DOIUrl":"10.1016/j.oceaneng.2025.120701","url":null,"abstract":"<div><div>With the development of marine economy, maritime activities are becoming more frequent, and the importance of maritime rescue missions is becoming increasingly prominent. Multi-UAVs collaborative search and rescue provides a new solution for maritime rescue, and the UAV path planning problem is one of the key challenges. First, this paper uses the lamb-Ossen model to simulate the sea wind and construct a 3D offshore environmental model with sea wind. Secondly, this paper comprehensively considers factors such as sea wind and distance between UAVs, and proposes a multi-UAVs path cost function. Meanwhile, a guided collaborative control mechanism is proposed to form a novel multi-UAVs collaborative path planning method. In addition, the multi-UAVs path solution uses an improved multi-Dimensional Coati Optimization Algorithm (MDCOA), designs new strategies through Levy flight, differential operator, and dynamic opposite learning, and adds a covariance matrix learning (CML) stage to expand the search perspective. Finally, the MDCOA algorithm was used to solve the multi-UAVs paths in different offshore simulation scenarios. The paths obtained by the algorithm reduced the path cost and showed excellent performance compared with other algorithms. Experimental results prove the effectiveness and scalability of the algorithm proposed in this paper.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"324 ","pages":"Article 120701"},"PeriodicalIF":4.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465412","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":"Numerical study on pressure drag reduction for a surface vessel with struts with the drag reduction mode of ventilated supercavitating combined with air layer","authors":"Hai An,&nbsp;Xinquan Liu,&nbsp;Hanyu Zhang,&nbsp;Zihao Cui","doi":"10.1016/j.oceaneng.2025.120727","DOIUrl":"10.1016/j.oceaneng.2025.120727","url":null,"abstract":"<div><div>There are few studies on pressure drag reduction for surface vessels. In this work, pressure drag reduction for a surface vessel model with struts with the joint drag reduction mode of ventilated supercavitating combined with air layer is numerically studied. Based on the VOF model and the SST k-ω turbulence model, the influences of the air flux at the different speed, the air layer thickness, and the distribution proportion of air flux between air vents on the pressure drag of the vehicle are studied. The study results show that first, the injected air provides an additional momentum source for the flow boundary layer and changes the inertia force caused by the migration acceleration of water in the flow field. Secondly, after the formation of air layer drag reduction, the drag reduction rate of the pressure drag of the vehicle increases linearly with the increase of the air layer thickness, while the drag reduction rate of the skin friction drag remains almost constant. Finally, the larger the distribution proportion of air flux of the leading edge air vents, the higher the drag reduction rate of the pressure drag, but the influence on the skin friction drag is small.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"324 ","pages":"Article 120727"},"PeriodicalIF":4.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465335","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":"Study on mechanism of propagation and deformation of random waves over a complex uneven coral reefs","authors":"X. Wang ,&nbsp;K. Qu ,&nbsp;J. Men ,&nbsp;R.Z. Gao ,&nbsp;C. Wang","doi":"10.1016/j.oceaneng.2025.120720","DOIUrl":"10.1016/j.oceaneng.2025.120720","url":null,"abstract":"<div><div>Coral reefs, which are widely distributed in tropical and subtropical seas, generally feature uneven coral reefs platforms. The variation in reef platform topography can significantly influence the propagation and transformation characteristics of incident waves over coral reefs. However, most previous studies are based on a relatively simple coral reef model, whose main structure is a geometric shape similar to a step, ignoring the complex features of the real topography of coral reefs. In this study, complex wave hydrodynamics and nonlinear characteristics of random waves at a composite reef model have been investigated through physical experiments. This coral reef model consists of a composite fore-reef slope, a reef-step connecting the outer reef flat and inner reef flat, and a lagoon. A systematic analysis was conducted to assess the effects of three different incident wave parameters—incident wave height, wave spectral peak period, and reef platform water depth—on wave propagation, transformation, and wave setup. The results indicate that uneven reef platforms enhance the nonlinear transformation of waves, with asymmetry and skewness reaching peak values near the reef platform step, thereby promoting the transfer of wave energy from primary frequency waves to higher harmonics. The stronger the wave's nonlinear transformation, the more significant the wave setup on the second reef platform. Additionally, as the incident wave height and wave spectral peak period increase, both the short-wave height and low-frequency wave height on the second reef platform increase, with the increase in low-frequency wave height being more pronounced in shallower water. When the wave spectral peak period is increased, standing waves may form on the first reef platform due to multiple wave reflections, leading to more wave energy transfer to higher harmonics near the reef platform step. The wave setup on the second reef platform exhibits nonlinear behavior.</div></div>","PeriodicalId":19403,"journal":{"name":"Ocean Engineering","volume":"324 ","pages":"Article 120720"},"PeriodicalIF":4.6,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143454271","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}