Applied Ocean Research最新文献

{"title":"Nonlinear long-term vibration response prediction of offshore wind turbines under full operating conditions based on deep learning","authors":"Hong Bai ,&nbsp;Jianhua Zhang ,&nbsp;Ke Sun ,&nbsp;Won-Hee Kang","doi":"10.1016/j.apor.2025.104625","DOIUrl":"10.1016/j.apor.2025.104625","url":null,"abstract":"<div><div>Efficient prediction of the vibration response of offshore wind turbines plays a crucial role in proactively identifying potential vibration hazards and enabling real-time adjustments to operational strategies. The simulation methods are limited by lengthy computation times. In addition, pure data-driven prediction models suffer from limited adaptability to unseen conditions and lack constraints based on physical mechanisms. This paper presents a new method combining deep learning and OpenFAST simulation to predict the nonlinear long-term vibration response of offshore wind turbines. The approach is designed to encompass all operating conditions. Firstly, a multi-layer stacked BiLSTM architecture is designed to capture long sequences of time-series data. Recursive calculations are implemented using a sliding time window approach, while independent parallel computations are achieved through the multiprocessing technology. Subsequently, the time series data of 68 different wind-wave load scenarios are obtained through OpenFAST analysis, and the vibration response is predicted using the deep learning framework. Furthermore, the multi-input recursive BiLSTM obtained from the novel method is compared with the existing time series model. The results demonstrate that the proposed model accurately replicates both global and local features of time-history responses across diverse offshore wind turbine datasets. The average computation time is only 1/744.97 of that required by simulation models. Moreover, within a 10 s forecast duration, the model maintains an average online prediction accuracy of 91.94 % across all operational conditions. Under extreme conditions, the prediction accuracy is 29.71 % and 17.52 % higher than those of the end-to-end BiLSTM and RNN models, respectively. This proposed method is particularly suitable for applications where traditional numerical methods are limited, such as rapid simulations under real-time changes in operating conditions within complex marine environments.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104625"},"PeriodicalIF":4.3,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144130865","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":"Solid bulk cargo liquefaction: numerical investigation and proposal of safety envelopes","authors":"Piotr Kowalczyk,&nbsp;Susan Gourvenec","doi":"10.1016/j.apor.2025.104607","DOIUrl":"10.1016/j.apor.2025.104607","url":null,"abstract":"<div><div>Liquefaction of solid bulk cargo during marine transportation is a cause of loss of vessels and life at sea, however limited research has been conducted to understand the mechanism and reduce risks. The work presented in this paper addresses this subject from the soil mechanics perspective through simplified numerical assessment carried out by means of a coupled hydromechanical finite element analysis with an advanced effective stress constitutive model (PM4Sand). Typical responses of solid bulk cargo to dynamic loading are discussed in terms of generation of excess pore pressure and its changes during loading, alongside dissipation and changes in the state of the cargo post-loading. Results of parametric studies are presented and show how various geotechnical characteristics of solid bulk cargo contribute to the risk of liquefaction. The parametric analyses are summarized in a proposed new framework of simplified safety envelopes.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104607"},"PeriodicalIF":4.3,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144123879","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":"Combined effect of ice cover and length-to-diameter ratio on the wave resistance of a slender body","authors":"Alexandra Pogorelova","doi":"10.1016/j.apor.2025.104622","DOIUrl":"10.1016/j.apor.2025.104622","url":null,"abstract":"<div><div>In this study we considered the rectilinear motion of a slender body in fluid under an ice cover. The liquid is inviscid and incompressible. The ice cover was modeled as a floating viscoelastic plate, and the slender body was modeled as a source–sink system in a fluid flow. The strength of the sources and sinks and the distances between them depend on the body form. The shape of the bow is elliptical, the middle shape is cylindrical, and the stern has a parabolic shape. We considered bodies with varying length-to-diameter ratios (<em>L</em>/<em>D</em> = 6, 8, 10, 12, 14, and 16) by adjusting the length of the parallel mid-body. The influence of the <em>L</em>/<em>D</em>, ice cover thickness, submergence depth, and speed of the submerged body on the wave resistance was analyzed. Results show that for a thin ice cover, the critical Froude number depends on the <em>L</em>/<em>D</em>. For a thick ice cover, the critical Froude number depends on the ice plate thickness. For all considered cases of the <em>L</em>/<em>D</em> and ice cover thickness, the fully submergence and Milestone depths were obtained.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104622"},"PeriodicalIF":4.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107343","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":"Under-consolidation characteristics of an offshore marine clay from Yellow Sea, China","authors":"Mingzhu Li ,&nbsp;Miaojun Sun ,&nbsp;Zhigang Shan ,&nbsp;Minyun Hu ,&nbsp;Shuaifeng Wu ,&nbsp;Hong Cai ,&nbsp;Mingjing Jiang","doi":"10.1016/j.apor.2025.104591","DOIUrl":"10.1016/j.apor.2025.104591","url":null,"abstract":"<div><div>Consolidation characteristics of marine soils are crucially important to ocean reclamation, pile foundation design and construction, etc. A series of oedometer tests were conducted on samples from three different depths in north Yellow Sea, China, to disclose the consolidation properties of the marine soil. Intact and reconstituted samples, under seawater or freshwater condition, were tested in loading, unloading and reloading processes. The pre-consolidation pressure was determined by double logarithmic method, and the consolidation coefficients were evaluated by Taylor’s method. Results show that the compressibility of the tested marine clay is much lower than other reported marine soils, with low liquid limit (<em>w</em>_L = 35.34∼42.22 %), low water content (<em>w</em> = 23.08∼25.91 %) and low permeability (<em>k</em> = 0.82∼1.57 × 10^-7cm/s). The consolidation coefficient is of 10^-4cm²/s and can be increased up to 416 % when the sample processes reloading after undergoing unloading. The intact sample is lower in compression index and higher in consolidation coefficient than reconstituted samples. Besides, in tests of reconstituted samples with seawater, the compression index of marine sample can be reduced and the consolidation coefficient can be improved. The determined pre-consolidation pressure indicates that the marine samples from different depths are all under-consolidated, which was verified by CPTU tests and explained by Gibson’s theory for clay sedimentation under water.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104591"},"PeriodicalIF":4.3,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107447","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":"Adaptive output feedback control for a two-dimensional flexible riser system based on backstepping method","authors":"Jianhua Zhang ,&nbsp;Meng Wang ,&nbsp;Xiaoyu Wang ,&nbsp;Ke Sun","doi":"10.1016/j.apor.2025.104611","DOIUrl":"10.1016/j.apor.2025.104611","url":null,"abstract":"<div><div>This paper addresses the vibration control problem of a two-dimensional flexible riser system with uncertain parameters and unmeasurable states. Adaptive output feedback controllers are proposed based on the backstepping method to suppress the vibration of the riser system. To this end, parameter adaptive laws are designed to compensate for uncertainties in system parameters. Additionally, high-gain observers and disturbance observers are introduced to estimate and compensate for unmeasurable states and time-varying boundary disturbance caused by environmental loads. The well-posedness and stability of the closed-loop system are mathematically demonstrated. The performance of the proposed controllers is evaluated through simulation.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104611"},"PeriodicalIF":4.3,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107342","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":"Pore-scale investigation of bubble evolution in shallow coastal gassy silt with micro-computed tomography","authors":"Zhenqi Guo ,&nbsp;Yunuo Liu ,&nbsp;Feiyan Jin ,&nbsp;Tao Liu ,&nbsp;Yan Zhang","doi":"10.1016/j.apor.2025.104609","DOIUrl":"10.1016/j.apor.2025.104609","url":null,"abstract":"<div><div>Shallow coastal gassy silts, characterized by isolated bubble trapping and heterogeneous bubble distribution within the sediment matrix, often serve as foundational substrates in nearshore and subsea engineering projects. Understanding the dynamic behavior of bubbles at the pore scale is crucial for evaluating the mechanical strength of gassy silts and their influence on engineering stability at a regional scale. In this study, we employed in-situ micro-computed tomography to investigate the effects of varying initial gas content and applied loading conditions on bubble evolution within gassy silts. Specimens were prepared using zeolite powder to simulate natural gas nucleation processes, with gas content levels of 2.0 % and 3.0 %, representing typical ranges of gas saturation observed in field conditions. These specimens were subjected to incrementally increasing vertical loads from 0 to 60 kPa, corresponding to pore scale stress conditions that simulate changes due to increasing water depths or geotechnical loads in coastal engineering applications. Our findings indicate that, with increasing stress, bubbles generally decrease in size, become more numerous, and shift toward more spherical shapes, aligning preferentially along directions parallel to stress transmission paths. The initial gas content plays a critical role in determining the processes of bubble evolution. Additionally, as loading intensifies, the total surface area of the bubbles decreases, suggesting a progression toward a more stable state for the gassy silt system overall. This work provides new pore-scale insights into bubble evolution in shallow coastal gassy silt.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104609"},"PeriodicalIF":4.3,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070779","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":"An experimental benchmark study on shape effects of structures under forced vertical oscillation: Flow fields, wave radiation, and hydrodynamic coefficients","authors":"Jannik Meyer ,&nbsp;Christian Windt ,&nbsp;Constantin Schweiger ,&nbsp;Clemens Krautwald ,&nbsp;Mario Welzel ,&nbsp;Arndt Hildebrandt ,&nbsp;Torsten Schlurmann ,&nbsp;Nils Goseberg","doi":"10.1016/j.apor.2025.104585","DOIUrl":"10.1016/j.apor.2025.104585","url":null,"abstract":"<div><div>Floating structures play a crucial role in transitioning from fossil fuels to renewable energies, either in floating offshore wind, floating solar, or wave energy applications. However, an accurate and efficient determination of the floating structures’ motion in waves remains a challenging task, particularly in mid-fidelity applications or applications with the aim of real-time capabilities: In particular, evaluating viscous effects and their importance for hydrodynamic damping is crucial. The wave radiation damping is often deemed dominant for vertically oscillating structures, but viscous effects cannot be neglected. The underlying physical processes of such viscous effects are not fully understood due to a lack of high-quality three-dimensional experimental flow field data. The present study investigates structures under forced vertical oscillation and aims at enhancing the physical understanding of the relation between structural shapes and features, the hydrodynamic parameters and the flow field using 3D time-resolved flow field measurements from a <em>particle tracking velocimetry</em> system. These investigations lead to a benchmark dataset for the development and validation of sophisticated numerical models which is published alongside this study. Three different generic box-type shapes are investigated: (i) a sharp-edged box, (ii) a round-edged box, and (iii) a box with a heave plate at the bottom. The experimental results show strong shape effects on the hydrodynamic coefficients, wave radiation, and the flow field. The radiated wave height can differ up to 50% between the three structures. Viscous effects from vortex structures and separation lead to a <span><math><mrow><mi>K</mi><mi>C</mi></mrow></math></span>-related increase of damping values for structures with sharp edges or heave plates. Significant shape effects on the vorticity are reported with a factor of up to 500% between the structures. Additionally to structural shape and features, the vorticity depends on <span><math><mrow><mi>K</mi><mi>C</mi></mrow></math></span> and oscillation frequency, while the vortex size solely depends on <span><math><mrow><mi>K</mi><mi>C</mi></mrow></math></span> and much less on structural shape (with a factor of up to 70%) and frequency. A comparison with potential flow simulations yields qualitatively good agreement to predict shape effects in added mass and radiation damping; however, a comparison between radiated wave heights from experiments and potential flow simulations indicates the necessity to validate potential flow results for quantitatively correct results.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104585"},"PeriodicalIF":4.3,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069679","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":"P-y curve models for laterally loaded lattice-shaped diaphragm wall as sea-crossing bridge foundations","authors":"Jiujiang Wu ,&nbsp;Longjun Pu","doi":"10.1016/j.apor.2025.104610","DOIUrl":"10.1016/j.apor.2025.104610","url":null,"abstract":"<div><div>Lattice-shaped diaphragm walls (LSDWs) are novel foundation systems increasingly used in large-span, deep-water bridges for their exceptional rigidity, cost-efficiency, and adaptability to diverse geotechnical and marine environments. Despite their growing adoption, the lateral load-bearing behavior of LSDWs remains insufficiently studied. The <em>p-y</em> curve method is a widely used approach for analyzing the lateral behavior of deep foundations, relating lateral soil resistance to horizontal displacement. However, conventional <em>p-y</em> curve models, developed primarily for pile foundations, are not directly applicable to LSDWs due to differences in structural configuration and load transfer mechanisms. To address this gap, this study develops improved <em>p-y</em> curve models for single-chamber LSDWs, derived from comprehensive numerical simulations under horizontal static loads in cohesive and sandy soils. The models incorporate foundation dimension and depth effects, accurately predicting ultimate soil resistance and initial subgrade reaction modulus. Validation against published field tests and experimental data confirms their high accuracy in capturing lateral soil-structure interactions. These findings provide valuable guidance for optimizing the design and analysis of LSDW foundations in marine bridge construction.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104610"},"PeriodicalIF":4.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069672","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 investigations of local scour around piles in a single-column and three-columns with multiple rows in steady current","authors":"Ming Gong ,&nbsp;Guoxiang Wu ,&nbsp;Shengtao Du ,&nbsp;Xinying Pan ,&nbsp;Yingxue Lv ,&nbsp;Yunjia Sun ,&nbsp;Guangjia Ding ,&nbsp;Bingchen Liang","doi":"10.1016/j.apor.2025.104608","DOIUrl":"10.1016/j.apor.2025.104608","url":null,"abstract":"<div><div>Local scour around pile groups is a common phenomenon in fluvial and coastal engineering, leading to a reduction in the bearing capacity of pile foundations frequently. In this study, experimental tests were conducted in a flume to investigate local scour around piles arranged in tandems of single-column and three-columns, with rows ranging from 1 to 5. The objective was to examine the effects of upstream piles and lateral piles on local scour around downstream and central piles, respectively. Bed elevation profiles and temporal scour depths were measured and observed, respectively. The results revealed that sediment particles accumulated in the spaces between the third and the fifth rows in the 5 × 1 configuration, while local scour holes extended into these areas in the 5 × 3 configuration. Temporal scour depths were successfully fitted to an equation that divides the local scour process into three stages: initial, developing, and equilibrium scouring. Piles on either side of the central piles contributed to larger and deeper scour holes compared to those observed in a single-column arrangement. Furthermore, the equilibrium scour depth was found to decrease linearly with an increasing number of pile rows. Coefficients for both single-column and three-column configurations were proposed to estimate reductions in equilibrium scour depths, based on well-fitted curves derived from the experimental data.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"159 ","pages":"Article 104608"},"PeriodicalIF":4.3,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069676","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 investigation of passive cavitation control on a cylinder using proper orthogonal decomposition","authors":"Pankaj Kumar ,&nbsp;Ebrahim Kadivar ,&nbsp;Ould el Moctar","doi":"10.1016/j.apor.2025.104569","DOIUrl":"10.1016/j.apor.2025.104569","url":null,"abstract":"<div><div>Cavitation is known for its hazardous effects such as material erosion, noise, vibration and drop in efficiency of hydro turbomachines. There are various approaches to control cavitation: surface roughness, cavity generator (CG), obstacles, and ventilation with air/water jetting. In the present work, we are aiming to examine the cavitation suppression by using riblets on the surface of a circular cylinder. The experiment will be carried out for two kinds of scalloped riblets, horizontal (SC-H) and vertical (SC-V), and compared without riblet cylinder (plain) at Reynolds number 1 × 10⁵. The local force is measured by using a load cell and dynamic pressure is monitored through a pressure sensor. The cavitation structures are first captured through the high-speed camera and analyzed through image processing by using Matlab. It is found that the lift force amplitude varies from 1.2 N of the plain cylinder to 0.57 and 0.48 N for the cylinder with horizontal and vertical riblets respectively. The dynamics of the cavity behind the cylinder are visible in the time-averaged mean image. The image is separated into three regions for a more in-depth examination: the far field, the center field, and the area adjacent to the cylinder. This serves to highlight certain important facts about cavity dynamics. In order to emphasize the spatial and temporal dynamics of coherent structures, the proper orthogonal decomposition (POD) is used. It is discovered that the POD modes of coherent structures can be well explained by the first five modes. Furthermore, it is found that while SC-V is capable of stabilizing the cavitation structures by limiting fragmentation, SC-H substantially controls the cavitation and chaotic behavior.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"158 ","pages":"Article 104569"},"PeriodicalIF":4.3,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886464","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}