Journal of Ocean Engineering and Science最新文献

{"title":"Real-time hybrid test method for floating wind turbines: Focusing on the aerodynamic load identification","authors":"Zhihao Jiang ,&nbsp;Binrong Wen ,&nbsp;Gang Chen ,&nbsp;Xinliang Tian ,&nbsp;Jun Li ,&nbsp;Danxue Ouyang ,&nbsp;Zhike Peng ,&nbsp;Yehong Dong ,&nbsp;Guiyong Zhou","doi":"10.1016/j.joes.2024.06.002","DOIUrl":"10.1016/j.joes.2024.06.002","url":null,"abstract":"<div><div>Since the development of floating wind turbine (FWT) shows a rapid trend towards larger capacity and larger rotor size, the traditional full-model basin test method has encountered limits. Especially the balance between the wind generation system (WGS) size and scale ratio of the model FWT system. Under such circumstances, the hybrid model test method provides the possibility to improve the FWT model test. In the hybrid model test method, the original physical model system is divided into physical subsystem and numerical subsystem, and the data acquisition and process module between the 2 subsystems plays an important role. In this paper, a framework of real-time hybrid test (RTHT) system is setup firstly, which combines physical model wind turbine and motion platform. The damping modification to the corresponding numerical code is applied to improve the motion calculation accuracy. Delay implementation is employed to avoid motion divergence. Then a simulation loop is setup in numerical environment to study the identification of aerodynamic load. The influence of identification accuracy to the RTHT result is analyzed. Lastly, the dual-accelerometer method of aerodynamic load identification is employed in the proposed RTHT system. Decay tests and irregular wave only tests are carried out to validate the aerodynamic load identification method. The capability and potential of the RTHT method of floating wind turbine model test is preliminary proved in the work of this paper.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 4","pages":"Pages 449-461"},"PeriodicalIF":13.0,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141694417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 load identification method based on frequency response pattern recognition and dynamic sensor filter strategy","authors":"Li Sun ,&nbsp;Deyu Wang ,&nbsp;Guijie Shi","doi":"10.1016/j.joes.2024.05.003","DOIUrl":"10.1016/j.joes.2024.05.003","url":null,"abstract":"<div><div>Identification of impact loads plays important role in marine structures health monitoring but is difficult to be measured directly most time. This study investigates a two-stage framework for impact load localization and reconstruction, consisting of load region identification and local refined nodal search. For the region identification, a novel frequency response feature preprocessing method based on FFT is proposed and incorporated into a multi-layer perceptron (MLP) neural network as the embedding function of the Matching Network (MN), the core model adopted for pattern recognition. Based on the region probabilities predicted by MN, a local refined nodal search strategy is provided, which is initialized by a region correction method for amending the possible region misclassification and further guided by error metrics with iteration search strategy. Moreover, the inverse problem in this study is formulated in the discretized state space expression with the reduced modal coordinates. For improving the load inverse accuracy affected by Zero Order Hold (ZOH) simplification in this formulation, a dynamic sensor filter strategy is provided. Eventually, a numerical experiment of impact load identification on a steel plate is performed and discussed, whose results indicate the validity and robustness of the proposed method.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 4","pages":"Pages 411-425"},"PeriodicalIF":13.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141275401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Is a direct numerical simulation (DNS) of Navier-Stokes equations with small enough grid spacing and time-step definitely reliable/correct?","authors":"Shijie Qin ,&nbsp;Yu Yang ,&nbsp;Yongxiang Huang ,&nbsp;Xinyu Mei ,&nbsp;Lipo Wang ,&nbsp;Shijun Liao","doi":"10.1016/j.joes.2024.04.002","DOIUrl":"https://doi.org/10.1016/j.joes.2024.04.002","url":null,"abstract":"<div><p>Turbulence is strongly associated with the vast majority of fluid flows in nature and industry. Traditionally, results given by the direct numerical simulation (DNS) of Navier-Stokes (NS) equations that relate to a famous millennium problem are widely regarded as ‘reliable’ benchmark solutions of turbulence, as long as grid spacing is fine enough (i.e. less than the minimum Kolmogorov scale) and time-step is small enough, say, satisfying the Courant-Friedrichs-Lewy condition (Courant number <span><math><mo>&lt;</mo></math></span> 1). Is this really true? In this paper a two-dimensional sustained turbulent Kolmogorov flow driven by an external body force governed by the NS equations under an initial condition with a spatial symmetry is investigated numerically by the two numerical methods with detailed comparisons: one is the traditional DNS, the other is the ‘clean numerical simulation’ (CNS). In theory, the exact solution must have a kind of spatial symmetry since its initial condition is spatially symmetric. However, it is found that numerical noises of the DNS are quickly enlarged to the same level as the ‘true’ physical solution, which finally destroy the spatial symmetry of the flow field. In other words, the DNS results of the turbulent Kolmogorov flow governed by the NS equations are badly polluted mostly. On the contrary, the numerical noise of the CNS is much smaller than the ‘true’ physical solution of turbulence in a long enough interval of time so that the CNS result is very close to the ‘true’ physical solution and thus can remain symmetric, which can be used as a benchmark solution for comparison. Besides, it is found that numerical noise as a kind of artificial tiny disturbances can lead to huge deviations at large scale on the two-dimensional Kolmogorov turbulence governed by the NS equations, not only quantitatively (even in statistics) but also qualitatively (such as spatial symmetry of flow). This highly suggests that fine enough spatial grid spacing with small enough time-step alone could not guarantee the validity of the DNS of the NS equations: it is only a necessary condition but not sufficient. All of these findings might challenge some of our general beliefs in turbulence: for example, it might be wrong in physics to neglect the influences of small disturbances to NS equations. Our results suggest that, from physical point of view, it should be better to use the Landau-Lifshitz-Navier-Stokes (LLNS) equations, which consider the influence of unavoidable thermal fluctuations, instead of the NS equations, to model turbulent flows.</p></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"9 3","pages":"Pages 293-310"},"PeriodicalIF":7.1,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2468013324000214/pdfft?md5=05f9e31d26b4448a68efd583d1819189&pid=1-s2.0-S2468013324000214-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141164449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Numerical study of a fish swimming in hydrokinetic turbine wake","authors":"Marianela Machuca Macias ,&nbsp;Rafael Castilho Faria Mendes ,&nbsp;José Hermenegildo Garcia-Ortiz ,&nbsp;Taygoara Felamingo Oliveira ,&nbsp;Antonio C.P. Brasil Junior","doi":"10.1016/j.joes.2024.03.001","DOIUrl":"10.1016/j.joes.2024.03.001","url":null,"abstract":"<div><div>The environmental effects of hydrokinetic turbines are still under investigation, reflecting the emerging status of this technology. This study investigates the interaction between hydrokinetic rotor wakes and fish swimming, revealing insights into fish biomechanics in complex flows and assessing the environmental implications of marine energy solutions. We conducted numerical simulations with the URANS approach and <span><math><mrow><mi>k</mi><mspace></mspace><mo>−</mo><mspace></mspace><mi>ω</mi><mspace></mspace><mo>−</mo><mspace></mspace><mi>S</mi><mi>S</mi><mi>T</mi></mrow></math></span> turbulence closure model to predict three-dimensional turbulent flow in the OpenFOAM software. The hydrokinetic rotor wake was simulated employing the actuator line method, providing a computationally efficient alternative to full geometry simulations. For accurate replication of the motion of a fish-like tuna (<em>Thunnus atlanticus</em>), dynamic adaptive mesh discretization was employed. The results offer a comparative analysis of fish swimming performance within the wake rotor, particularly when immersed in the tip blade vortex, contrasted with scenarios where fish swim in undisturbed flow conditions. The analysis encompasses three-dimensional wake structures, force generation, efficiency, and equilibrium states (balancing drag and thrust) across varying Swimming numbers (<span><math><mrow><mi>S</mi><mi>w</mi></mrow></math></span>). Key findings include the enhanced attachment of the leading-edge vortex due to the caudal fin’s interaction with the tip blade vortex, resulting in improved auto-propulsive force production; a reduced tail stride frequency observed in fish swimming downstream of the rotor to achieve longitudinal force balance compared to unperturbed flow; and transverse hydrodynamic forces pushing fish radially away from the wake’s influence zone, potentially mitigating the risk of collision with turbine blades.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 4","pages":"Pages 602-620"},"PeriodicalIF":13.0,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140269457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 transfer learning-based method for marine machinery diagnosis with small samples in noisy environments","authors":"Yongjin Guo ,&nbsp;Chao Gao ,&nbsp;Yang Jin ,&nbsp;Yintao Li ,&nbsp;Jianyao Wang ,&nbsp;Qing Li ,&nbsp;Hongdong Wang","doi":"10.1016/j.joes.2023.12.004","DOIUrl":"10.1016/j.joes.2023.12.004","url":null,"abstract":"<div><div>The operating conditions of marine machinery are demanding, and their operational state significantly affects the safety of marine structures. Detecting faults is crucial for machinery health management and necessitates a highly precise diagnostic method. In this paper, we propose a fault diagnosis framework that employs transfer learning and dynamics simulation. A denoising convolutional autoencoder is used to reduce noise when monitoring vibration data in marine environments. To address the challenge of limited sample sizes in marine machinery fault data, a multibody dynamics simulation model is developed to acquire data under fault conditions. The fault features are extracted using a convolutional neural network model. Parameter transfer is applied to enhance the accuracy of fault diagnosis. The effectiveness and applicability of the framework are demonstrated through a case study of a bearing fault dataset.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 4","pages":"Pages 593-601"},"PeriodicalIF":13.0,"publicationDate":"2023-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139190660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cooperative control for automatic towing operation by multiple DP tugboats with fully unknown model parameters","authors":"Xu Jiang, Yiming Zhu, Lei Wang, Yiting Wang","doi":"10.1016/j.joes.2023.12.005","DOIUrl":"https://doi.org/10.1016/j.joes.2023.12.005","url":null,"abstract":"","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"28 1-2","pages":""},"PeriodicalIF":7.1,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139194492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the dynamic response of a floating wind-aquaculture platform under the combined actions of wind, waves and current","authors":"Qixiang Fan,&nbsp;Yuwang Xu,&nbsp;Qianhui Xie,&nbsp;Mengmeng Zhang,&nbsp;Haojie Ren,&nbsp;Tongxiao Sun","doi":"10.1016/j.joes.2023.11.003","DOIUrl":"10.1016/j.joes.2023.11.003","url":null,"abstract":"<div><div>Floating wind-aquaculture platforms are drawing increasing attention from the academic and engineering communities due to their potential to fully exploit and utilize marine space and its resources. However, these platforms integrate both the hydrodynamics and aerodynamics of floating wind turbines and aquaculture cages, making their mechanical properties more complex. This study aims to evaluate the effects of three different hydrodynamic and aerodynamic damping components on and the contribution of the stochastic environmental loads to the dynamic response of a floating wind-aquaculture platform. A coupled hydro-aero-servo method is established. Decay and forced oscillation tests of the platform in still water are firstly numerically performed, followed by simulation of the dynamic behavior under different combinations of environmental loads, including the fluctuating wind load of the blades, stochastic wave excitation forces on the floating body and viscous force of the aquaculture cage system. The aerodynamic damping of the wind turbine and the hydrodynamic damping of the floating body are dominant in low- and wave-frequency range, respectively. Regarding the environmental load components, the second-order wave force and the turbulent wind load are dominant in the surge direction in the low-frequency range. The dynamic response of the platform in the wave-frequency range is mainly induced by the first-order wave force. Fish nets can suppress the low-frequency motion but have almost no influence on the wave-frequency motion.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 4","pages":"Pages 580-592"},"PeriodicalIF":13.0,"publicationDate":"2023-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139291521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Message from the head, State Key Laboratory of Ocean Engineering","authors":"","doi":"10.1016/S2468-0133(23)00083-9","DOIUrl":"https://doi.org/10.1016/S2468-0133(23)00083-9","url":null,"abstract":"","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"8 6","pages":"Page iv"},"PeriodicalIF":7.1,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2468013323000839/pdfft?md5=0c4bd9cec787c566deaf6415bacc2368&pid=1-s2.0-S2468013323000839-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138335387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Introduction to the discipline of Naval Architecture and Ocean Engineering, Shanghai Jiao Tong University","authors":"","doi":"10.1016/S2468-0133(23)00082-7","DOIUrl":"https://doi.org/10.1016/S2468-0133(23)00082-7","url":null,"abstract":"","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"8 6","pages":"Page iii"},"PeriodicalIF":7.1,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2468013323000827/pdfft?md5=7af20a1be10bb317cc526d2967429681&pid=1-s2.0-S2468013323000827-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138335386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Eight Key Open Questions in Ocean Engineering","authors":"","doi":"10.1016/S2468-0133(23)00084-0","DOIUrl":"https://doi.org/10.1016/S2468-0133(23)00084-0","url":null,"abstract":"","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"8 6","pages":"Pages v-vi"},"PeriodicalIF":7.1,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2468013323000840/pdfft?md5=72e18d53f89692bf051e9381e69cd361&pid=1-s2.0-S2468013323000840-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138404240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}