Applied Ocean Research最新文献

{"title":"Numerical study on removal of offshore wind turbine monopile foundations using hydraulic pressure","authors":"Mina Shabouee ,&nbsp;Soheil Salahshour ,&nbsp;Muk Chen Ong ,&nbsp;Afrouz Nematzadeh","doi":"10.1016/j.apor.2025.104646","DOIUrl":"10.1016/j.apor.2025.104646","url":null,"abstract":"<div><div>Many offshore wind farms installed in the beginnings of the 90 s and 2000s are approaching the end of their design lifetime, and the need of decommissioning these structures has become imminent. This study introduces a numerical approach for the complete removal of monopiles using hydraulic extraction. The numerical modeling of this study mimics the process of water injection into a pile with a sealed joint at its top, which results in increased internal pressure that ultimately moves the pile upward. A Coupled Eulerian-Lagrangian (CEL) approach within ABAQUS/Explicit is employed in the analysis. Using this approach, water injection process is simulated, and deformations of soil are captured. Moreover, to examine the movement of the pile during the removal process in fully saturated dense sand, modified Mohr-Coulomb (MMC) model is utilized. The MMC model, chosen for its ability to capture the non-linear pre-peak hardening and post-peak softening of dense sand, covers limitations in the conventional Mohr-Coulomb (MC) model. These two tools have been used to analyze pile-soil-water interaction. A parametric study is carried out on water injection rate to assess its effects on extraction rate. Breakout pressure which is required to trigger pile movement is determined for dense sand (<span><math><mrow><msub><mi>I</mi><mi>D</mi></msub><mo>=</mo><mn>0.7</mn></mrow></math></span>) soil. The trend of the extraction rate based on the water injection rate seen in this numerical study for dense sand is in good agreement with the published experimental results.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"160 ","pages":"Article 104646"},"PeriodicalIF":4.3,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144212065","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":"Robust control method for automatic berthing of unmanned ships based on weight optimal loop shaping","authors":"Kai Feng ,&nbsp;Xiaoyuan Wang ,&nbsp;Jingheng Wang ,&nbsp;Yufeng Liang ,&nbsp;Quanzheng Wang ,&nbsp;Junyan Han ,&nbsp;Longfei Chen ,&nbsp;Cheng Shen ,&nbsp;Bin Wang","doi":"10.1016/j.apor.2025.104601","DOIUrl":"10.1016/j.apor.2025.104601","url":null,"abstract":"<div><div>Automatic berthing is one of the key functions for autonomous navigation of unmanned ships, and it is an important technology that assists and ensures ships complete their voyage tasks. To enhance the robustness, scenario universality, and disturbance resistance of automatic berthing technology, an automatic berthing method based on weight optimal loop shaping is proposed in this paper. Firstly, to enhance the robust stability margins of the berthing controller, the concept of weight optimization is introduced to transform the frequency-domain dependent weight optimization into an optimization problem with a finite number of frequency-domain independent constraints. Secondly, to improve the continuity and scenario universality of the algorithm, a transformation model between berth and earth coordinates is constructed using Bézier curves, and a forward Euler signal tracking method is introduced to provide a differentiable reference trajectory for the control system. Finally, the proposed method is validated through the construction of various berthing scenarios. The validation results indicate that the proposed method can achieve automatic berthing in different scenarios with better stability and disturbance resistance, and a theoretical reference is provided for the development of autonomous berthing technology for unmanned ships.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"160 ","pages":"Article 104601"},"PeriodicalIF":4.3,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144203034","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":"Power optimization modelling as a computational tool for power take off design in wave energy converters","authors":"Marcos Blanco ,&nbsp;Isabel Villalba ,&nbsp;Marcos Lafoz ,&nbsp;Jorge Nájera ,&nbsp;Gustavo Navarro ,&nbsp;Miguel Santos-Herrán","doi":"10.1016/j.apor.2025.104628","DOIUrl":"10.1016/j.apor.2025.104628","url":null,"abstract":"<div><div>This study presents a computational tool called Power Take-Off Optimisation Modelling (POM), a methodology for optimizing the design parameters of the Power Take-Off (PTO) in wave energy converters (WECs). POM uses a control optimization algorithm based on a differential evolution multi-objective approach to maximize the electrical power extracted by WECs while minimizing design costs.</div><div>The methodology integrates a wave-to-wire (W2W) model in the time domain, including a PTO loss model. It also considers the sea states where WECs operate, and constraints related to the PTO rated force. These features allow a comprehensive evaluation of the electrical energy generated and the optimization of PTO design parameters.</div><div>POM has been applied to a real case study involving a linear generator-based PTO operating under different sea states. The analysis includes four WEC technologies and two sea states to assess the tool’s effectiveness.</div><div>Results show that PTO length influences not only CAPEX minimization but also optimal modular system design. Additionally, a sensitivity analysis indicates that the number of modules required to meet force requirements is not significantly affected by PTO efficiency.</div><div>In conclusion, POM is a versatile support tool for technology developers and researchers, helping optimize PTO design to balance WEC manufacturing costs and generated power.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"160 ","pages":"Article 104628"},"PeriodicalIF":4.3,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189336","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":"Energy-based ue - εvp coupled incremental model of saturated marine coral sand subjected to cyclic loading","authors":"Yi Fang ,&nbsp;Kai Ren ,&nbsp;Qi Wu ,&nbsp;Qifei Liu ,&nbsp;Guoxing Chen","doi":"10.1016/j.apor.2025.104631","DOIUrl":"10.1016/j.apor.2025.104631","url":null,"abstract":"<div><div>Evaluating the stability of coral islands and reefs in dynamic marine environments, such as waves, tsunamis, storm surges, and earthquakes, is a critical scientific issue in the field of marine geotechnical engineering. Nansha coral sand was used as the study object, and stress-controlled drained and undrained cyclic-loading tests were conducted. The undrained excess pore-water pressure and the drained cumulative volumetric strain of saturated coral sand were determined at various non-plastic fine contents (<em>FC</em>), relative density (<em>D</em>_r), and cyclic stress ratio (CSR). The results indicated that cumulative volumetric strain (<em>ε</em>_vp) developed in coral sand via two modes: cyclic stabilisation and cyclic creep. Analyses revealed that when the potential damage coefficient (DP) × CSR &lt; 0.05, <em>ε</em>_vp remained in the cyclic stabilisation mode and when DP × CSR &gt; 0.05, <em>ε</em>_vp transitioned into the cyclic creep mode. Utilising cumulative dissipation energy as a linking factor showed an arctangent function relationship between the excess pore water pressure ratio (<em>R</em>_u) and <em>ε</em>_vp values of saturated coral sand with different <em>FC, D</em>_r, and CSR. This relationship was applicable to both stress- and strain-controlled cyclic-loading tests. Parameters <em>m</em> and <em>n</em> of the <em>R</em>_u–<em>ε</em>_vp function model increased with an increasing CSR. Additionally, an increase in the <em>D</em>_r or <em>FC</em> resulted in a decrease in <em>m</em> and an increase in <em>n</em>. Multiple regression analysis further revealed that model parameters corrected for compactness and cyclic stress levels exhibited distinct trends as the void ratio (<em>e</em>) increased. Specifically, <em>CSR^α</em> × <em>m^D</em>^r decreased, and <em>CSR</em>^1-<em>^α</em> × <em>n^D</em>^r increased. Both parameters displayed a single power function relationship with <em>e</em>. Based on these findings, a coupled incremental model for the cyclic pore pressure and volumetric strain of saturated coral sand, based on energy conversion, was developed.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"160 ","pages":"Article 104631"},"PeriodicalIF":4.3,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185567","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 ordering of cyclic loading sequences on the short-term performance of offshore monopiles in an overconsolidated clay","authors":"Iwinosa O. Aghedo ,&nbsp;Mohamed Rouainia","doi":"10.1016/j.apor.2025.104630","DOIUrl":"10.1016/j.apor.2025.104630","url":null,"abstract":"<div><div>Wind and wave actions that vary in amplitude, frequency and direction cause irregular cyclic loading on monopiles supporting offshore wind turbines (OWTs), resulting in cumulative deformation. Current design practice apply widely accepted classification methods to decompose a storm history into an idealised series of cyclic load parcels with uniform amplitude, ordered in magnitude. This approach is based on Miner’s rule, which assumes that the final accumulated deformation in the soil is independent of the sequence in which load cycles are applied. Research has shown this approach to be reasonable under drained conditions in sand. This study investigates the validity of this assumption under fully undrained conditions in clay through a series of three dimensional (3D) finite element analyses incorporating an advanced soil constitutive model. A large diameter monopile installed in an overconsolidated clay deposit is subjected to cyclic loading sequences arranged in ascending, descending, and mixed-sorted order. The effect of the load ordering sequence is demonstrated by comparing local soil behaviour in terms of cyclic ratcheting, strain accumulation, clay-structure degradation and excess pore-water pressure buildup and linking these to the global pile response in terms of pile rotation, stiffness, and damping. Findings show that under fully undrained conditions, the ordering of cyclic load sequence notably affects the performance of monopiles in overconsolidated clay deposits. These results suggest that experimental investigations are needed to further explore cyclic loading sequences on monopiles in clay, which could inform the development of improved numerical and design procedures for offshore monopiles.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"160 ","pages":"Article 104630"},"PeriodicalIF":4.3,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185566","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 4 foils hydrofoiler regulation solution and experiments","authors":"Lionel Lapierre ,&nbsp;Laurent Latorre ,&nbsp;Loic Daridon ,&nbsp;Denis Julien ,&nbsp;Vincent Dufour","doi":"10.1016/j.apor.2025.104596","DOIUrl":"10.1016/j.apor.2025.104596","url":null,"abstract":"<div><div>This paper introduces the Black Pearl, a novel 4-foil electric hydrofoiler, by presenting its design, control structure, and experimental findings. The innovative aspect of our approach lies in the redundant design of the sustentation structure, which utilizes four independent foils to control three degrees of freedom: roll, pitch, and altitude above the water.</div><div>This redundancy improves actuation efficiency, significantly reducing the risk of actuation saturation. Moreover, the explicit management of this redundancy ensures robust actuation performance, even in scenarios where one foil becomes locked at a fixed angle.</div><div>The paper also presents experimental trials conducted on the Black Pearl prototype, as well as the proposal and simulation testing of novel guidance laws designed to enhance the hydrofoiler’s flight performance.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"160 ","pages":"Article 104596"},"PeriodicalIF":4.3,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144170262","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 optimisation of the man overboard manoeuvre","authors":"Bas J. de Kruif,&nbsp;Bülent Düz,&nbsp;Victor Ferrari","doi":"10.1016/j.apor.2025.104603","DOIUrl":"10.1016/j.apor.2025.104603","url":null,"abstract":"<div><div>In maritime operations, the safety of crew and passengers is paramount, making the man overboard manoeuvre a critical emergency procedure for all vessels. Among the different ways to perform this manoeuvre, the Williamson turn is used to come back on its own wake to retrieve the man overboard. This manoeuvre is especially useful if it is not precisely known when the person fell overboard. During this manoeuvre the rudder is switched to its extremes at well defined heading deviations. The IAMSAR guideline provides standard values for these, but these values do not guarantee that the vessel will sail back on its own wake.</div><div>In this study we first estimated these switching angles with a numerical model and a data-driven model. Next, we used update rules to fine-tune these switching angles and tested those in a 1:24 model-scale experiment in one of MARIN’s basins.</div><div>After one iteration in the basin the lateral error and heading error were within DNV GL’s guidelines. The predicted switching angles from the numerical model were closer to the experimentally found values. However, the course and speed were better predicted with the data-driven model. The approach lends itself well to minimise commissioning time of a new vessel, and the switching angles found could be included on the wheelhouse-chart for a better execution of the Williamson turn.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"160 ","pages":"Article 104603"},"PeriodicalIF":4.3,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154497","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":"Tall salt marshes play a crucial role in the long-term geomorphic evolution of the Jiuduansha wetland, Yangtze estuary, China","authors":"Hao Ma ,&nbsp;Lihua Wang ,&nbsp;Paula D. Pratolongo ,&nbsp;Guoxiang Wu ,&nbsp;Benwei Shi","doi":"10.1016/j.apor.2025.104623","DOIUrl":"10.1016/j.apor.2025.104623","url":null,"abstract":"<div><div>Salt marshes play a pivotal role in shaping coastal wetlands by influencing hydrodynamics and sediment transport, a topic that has garnered increasing attention in recent studies. However, the specific roles of different vegetation types in driving geomorphic evolution remain unclear. This study aims to assess the impact of varying salt marsh vegetation on the long-term geomorphic evolution of coastal wetlands. Using 1449 satellite images spanning 39 years (1984–2023) from the Google Earth Engine data archive, we investigated how different salt marsh types influences geomorphic changes on Jiuduansha Island, the largest uninhabited island in the Yangtze Estuary, China. Our analysis focused on the long-term salt marsh expansion and geomorphic evolution of Jiuduansha. The results revealed that the total area of Jiuduansha, as well as the extent of tall salt marshes, has increased significantly over the past decade. Notably, tall salt marshes exert a profound influence on geomorphic evolution. Specifically, in the accretionary sections of Jiuduansha Island, the natural expansion of tall salt marshes (<em>Spartina alterniflora</em> and <em>Phragmites australis</em>, with mean heights of 1.8 m and 2.5 m, respectively) drives seaward progradation. Conversely, in erosional sections, these tall salt marshes play a crucial role in mitigating further shoreline erosion. This study underscores the significant role of tall salt marshes in the long-term geomorphic evolution of coastal wetlands, offering valuable insights into the dynamics of wetland ecosystems and their resilience to environmental changes.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104623"},"PeriodicalIF":4.3,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154674","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":"Vegetation stem dynamics under wave loading: Insights from a coupled fluid–structure model","authors":"Inga Prüter ,&nbsp;Felix Spröer ,&nbsp;Oliver Lojek ,&nbsp;Christian Windt ,&nbsp;David Schürenkamp ,&nbsp;Ioan Nistor ,&nbsp;Nils Goseberg","doi":"10.1016/j.apor.2025.104597","DOIUrl":"10.1016/j.apor.2025.104597","url":null,"abstract":"<div><div>Accurate replication of the stem motion of submerged aquatic vegetation is crucial to gain insights into its capacity for coastal protection and adaptability, such as the wave attenuation capacity and local sediment mobilization. The fluid–structure interaction solver within the numerical model REEF3D::CFD is validated, and then further employed to analyze vegetation stem motion and resulting drag forces, under wave loads using reference experiments, and covering a wide range of material properties and hydrodynamic conditions found in natural aquatic vegetation. Good agreement between simulated and experimental results is achieved for most test cases. This is expressed by less than 10<!--> <!-->% deviation of the simulated to the experimental forces and the stem positions relative to the stem length. To investigate possible sources of discrepancies between the numerical and experimental results, the flow field in front of the stem is compared with that measured during the reference experiments. Bending modes of stem movements provide further insights into the complex dynamic behavior of stems. Additionally, the study demonstrates the influence of the model’s built-in damping coefficients on the time-dependent stem movement under wave load for different material types. For all tested material types, the findings suggest that the use of damping coefficients ranging between 1 <span><math><mo>×</mo></math></span> 10^-8 and 1 <span><math><mo>×</mo></math></span> 10^-6 led to the successful replication of the stem dynamics and the resulting drag forces. Accurate predictions of vegetation response to wave loading require careful selection of the governing parameters in the structural model replicating the stem. Considering this, the proposed fluid–structure interaction solver proves highly effective for simulating a wide range of flexible, submerged vegetation stems.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104597"},"PeriodicalIF":4.3,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144135195","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":"Track-to-track association from diverse source ship trajectory based on an improved graph neural network","authors":"Jiangnan Zhang ,&nbsp;Zhenxing Liu ,&nbsp;Yanhai Gan ,&nbsp;Yongshuo Liu ,&nbsp;Junyu Dong","doi":"10.1016/j.apor.2025.104598","DOIUrl":"10.1016/j.apor.2025.104598","url":null,"abstract":"<div><div>With the development of maritime surveillance technologies, large volumes of ship trajectory data have been collected through various monitoring methods. The accuracy of targets tracking can be significantly improved by associating these trajectories, particularly in cases of partial equipment monitoring failures. Different acquisition approaches and data standards of marine monitoring methods lead to differences in the quality and precision of ship trajectory data from diverse sources, which significantly affects the accuracy of track-to-track association. According to AIS and Radar trajectory data, a novel multi-graph neural network combined with Cross-Attention (CA-MGNN) is proposed to realize the association with precision bias. The MGNN module is employed to convert AIS and Radar trajectory points into corresponding features, which are extracted from multiple spatiotemporal dimensions. The interactive features are then constructed by Cross-Attention mechanism, thereby achieving the association based on trajectory features. Experimental results demonstrate that the proposed method achieves high efficiency with association accuracy of 92.61% and inference time of 83.4 (ms), thereby providing more accurate tracking information to meet the demands of maritime awareness application.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104598"},"PeriodicalIF":4.3,"publicationDate":"2025-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130866","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}