Applied Ocean Research最新文献_第8页

Enhanced vibration-based damage detection for monopile offshore structures considering soil interaction based on VMD and deep CNN-LSTM 基于VMD和深度CNN-LSTM的考虑土相互作用的海上单桩结构振动损伤增强检测

IF 4.4 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-11-14 DOI: 10.1016/j.apor.2025.104856

Zohreh Mousavi , Ru-Ming Feng , Mohammadreza Farhadi , Mir Mohammad Ettefagh , Meysam Bayat , Sina Varahram , Wei-Qiang Feng

Offshore structures, such as monopile Offshore Wind Turbines (OWTs), are subjected to various dynamic loads including waves, wind, and operational vibrations, which can lead to different types of damage. A key consideration in Structural Health Monitoring (SHM) for offshore structures is how soil-structure interaction influences vibration-based damage detection systems. Extracting features manually from vibration signals is often complex, time-consuming, highlighting the need for automatic methods that can learn relevant features straight from raw data. This paper presents a novel vibration-based method for automatic feature learning and damage detection in offshore structures, taking soil interaction into account. A combined deep Convolutional Neural Network and Long Short-Term Memory (CNN-LSTM) network is developed to extract the relevant features from vibration signals reconstructed using the Variational Mode Decomposition (VMD) technique. Integrating the LSTM network with the CNN enhances the detection accuracy and stability while reducing the oscillation. Notably, the proposed method applies VMD-reconstructed vibration signals directly to the deep CNN-LSTM network without requiring separate feature extraction or selection. The VMD technique removes irrelevant components of the vibration signals that do not pertain to the structure’s nature, thereby refining the signals for a more accurate representation of the structure’s condition. The suggested method is verified utilizing experimental data from a lab-scale monopile offshore model that incorporates soil interaction. Vibration data were collected using various accelerometer sensors across different states, including one healthy state and eight damaged states. The results demonstrate that the proposed method effectively learns features from reconstructed vibration data and outperforms comparative methods, making it a promising approach for SHM system development in offshore structures.

海上结构，如单桩海上风力涡轮机（OWTs），受到各种动态载荷，包括波浪、风和运行振动，这可能导致不同类型的损伤。海洋结构健康监测（SHM）的一个关键问题是土-结构相互作用如何影响基于振动的损伤检测系统。手动从振动信号中提取特征通常是复杂且耗时的，因此需要能够直接从原始数据中学习相关特征的自动方法。本文提出了一种基于振动的海洋结构自动特征学习和损伤检测方法。为了从变分模态分解（VMD）技术重构的振动信号中提取相关特征，建立了一种深度卷积神经网络和长短期记忆（CNN-LSTM）网络。将LSTM网络与CNN相结合，提高了检测精度和稳定性，同时减少了振荡。值得注意的是，该方法将vmd重构的振动信号直接应用到深度CNN-LSTM网络中，而不需要单独提取或选择特征。VMD技术去除振动信号中与结构性质无关的成分，从而改进信号，更准确地表示结构的状态。利用包含土壤相互作用的实验室规模近海单桩模型的实验数据验证了所建议的方法。在不同的状态下，包括一个健康状态和八个损坏状态，使用不同的加速度传感器收集振动数据。结果表明，该方法可以有效地从重构的振动数据中学习特征，并优于其他比较方法，是一种很有前途的海上结构SHM系统开发方法。

{"title":"Enhanced vibration-based damage detection for monopile offshore structures considering soil interaction based on VMD and deep CNN-LSTM","authors":"Zohreh Mousavi , Ru-Ming Feng , Mohammadreza Farhadi , Mir Mohammad Ettefagh , Meysam Bayat , Sina Varahram , Wei-Qiang Feng","doi":"10.1016/j.apor.2025.104856","DOIUrl":"10.1016/j.apor.2025.104856","url":null,"abstract":"<div><div>Offshore structures, such as monopile Offshore Wind Turbines (OWTs), are subjected to various dynamic loads including waves, wind, and operational vibrations, which can lead to different types of damage. A key consideration in Structural Health Monitoring (SHM) for offshore structures is how soil-structure interaction influences vibration-based damage detection systems. Extracting features manually from vibration signals is often complex, time-consuming, highlighting the need for automatic methods that can learn relevant features straight from raw data. This paper presents a novel vibration-based method for automatic feature learning and damage detection in offshore structures, taking soil interaction into account. A combined deep Convolutional Neural Network and Long Short-Term Memory (CNN-LSTM) network is developed to extract the relevant features from vibration signals reconstructed using the Variational Mode Decomposition (VMD) technique. Integrating the LSTM network with the CNN enhances the detection accuracy and stability while reducing the oscillation. Notably, the proposed method applies VMD-reconstructed vibration signals directly to the deep CNN-LSTM network without requiring separate feature extraction or selection. The VMD technique removes irrelevant components of the vibration signals that do not pertain to the structure’s nature, thereby refining the signals for a more accurate representation of the structure’s condition. The suggested method is verified utilizing experimental data from a lab-scale monopile offshore model that incorporates soil interaction. Vibration data were collected using various accelerometer sensors across different states, including one healthy state and eight damaged states. The results demonstrate that the proposed method effectively learns features from reconstructed vibration data and outperforms comparative methods, making it a promising approach for SHM system development in offshore structures.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104856"},"PeriodicalIF":4.4,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526201","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}

引用次数: 0

A new CFD-MBD wave-structure interaction model: Coupling OpenFOAM with Chrono 一种新的CFD-MBD波结构相互作用模型：OpenFOAM与Chrono耦合

IF 4.4 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-11-13 DOI: 10.1016/j.apor.2025.104824

Haifei Chen , Tianyuan Wang , Deborah Greaves , Hongda Shi , Qingping Zou

Interconnected multibody floating structures have gained popularity recently. The dynamic response of moored interconnected floating bodies to wave action, however, are complicated and challenging to model and analyze. To tackle the problem, a novel wave-structure-interaction (WSI) model is developed for the first time by coupling a finite volume CFD model, OpenFOAM, with Project Chrono, a multi-physics simulation engine for multibody dynamics (MBD) and finite element analysis, through linking pre-compiled dynamic libraries. This paper focuses on dynamic behavior of rigid structures restrained with a mooring system. To account for the floating body motion in the fluid solver, both mesh deformation and overset mesh methods are incorporated in the WSI model. The rigid body motion solver integrates two dynamic mooring models (MoorDyn and Moody) to simulate the seakeeping functionality. It also incorporates OpenFAST to simulate the aerodynamics, servo control and structural dynamics of floating offshore wind turbines (FOWTs). The proposed modeling framework is validated and verified against six test cases, ranging from a single floating body such as a floating wind semi-submersible platform and a point absorber wave energy converter (WEC) to a two-body hinged raft. It was found the newly developed WSI modeling framework using only the aforementioned open-source codes achieved the same level of agreement with observations as its commercial counterpart, paving the way for free high-fidelity CFD simulations for the emerging hybrid wind-wave energy and floating solar systems.

近年来，互联多体浮体结构得到了广泛的应用。然而，系泊互联浮体对波浪作用的动力响应是复杂的，建模和分析具有挑战性。为了解决这个问题，通过连接预编译的动态库，将有限体积CFD模型OpenFOAM与Project Chrono（用于多体动力学（MBD）和有限元分析的多物理场模拟引擎）耦合在一起，首次开发了一种新的波-结构-相互作用（WSI）模型。本文主要研究系泊系统约束下刚性结构的动力特性。为了考虑流体求解器中的浮体运动，在WSI模型中引入了网格变形和偏移网格方法。刚体运动求解器集成了两个动态系泊模型（MoorDyn和Moody）来模拟耐浪功能。它还结合了OpenFAST来模拟浮式海上风力涡轮机（FOWTs）的空气动力学、伺服控制和结构动力学。所提出的建模框架通过六个测试案例进行了验证和验证，测试案例包括单浮体，如浮动风半潜式平台和点吸收波能转换器（WEC），以及两体铰链筏。研究发现，仅使用上述开源代码的新开发的WSI建模框架与观测结果达到了与商业对应的相同水平，为新兴的混合风波能和浮动太阳能系统的免费高保真CFD模拟铺平了道路。

{"title":"A new CFD-MBD wave-structure interaction model: Coupling OpenFOAM with Chrono","authors":"Haifei Chen , Tianyuan Wang , Deborah Greaves , Hongda Shi , Qingping Zou","doi":"10.1016/j.apor.2025.104824","DOIUrl":"10.1016/j.apor.2025.104824","url":null,"abstract":"<div><div>Interconnected multibody floating structures have gained popularity recently. The dynamic response of moored interconnected floating bodies to wave action, however, are complicated and challenging to model and analyze. To tackle the problem, a novel wave-structure-interaction (WSI) model is developed for the first time by coupling a finite volume CFD model, OpenFOAM, with Project Chrono, a multi-physics simulation engine for multibody dynamics (MBD) and finite element analysis, through linking pre-compiled dynamic libraries. This paper focuses on dynamic behavior of rigid structures restrained with a mooring system. To account for the floating body motion in the fluid solver, both mesh deformation and overset mesh methods are incorporated in the WSI model. The rigid body motion solver integrates two dynamic mooring models (MoorDyn and Moody) to simulate the seakeeping functionality. It also incorporates OpenFAST to simulate the aerodynamics, servo control and structural dynamics of floating offshore wind turbines (FOWTs). The proposed modeling framework is validated and verified against six test cases, ranging from a single floating body such as a floating wind semi-submersible platform and a point absorber wave energy converter (WEC) to a two-body hinged raft. It was found the newly developed WSI modeling framework using only the aforementioned open-source codes achieved the same level of agreement with observations as its commercial counterpart, paving the way for free high-fidelity CFD simulations for the emerging hybrid wind-wave energy and floating solar systems.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104824"},"PeriodicalIF":4.4,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526203","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}

引用次数: 0

A new integrated numerical wave tank in OpenFOAM for hydrodynamic modelling of offshore renewables OpenFOAM中用于海上可再生能源水动力模拟的新型集成数值波浪槽

IF 4.4 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-11-13 DOI: 10.1016/j.apor.2025.104858

Ranjodh Rai , Zhihua Ma , Ling Qian , Wei Bai , Zaibin Lin

This paper presents a new integrated hydrodynamic modelling framework for wave–structure interaction problems. It is developed by coupling a finite-volume-based fully nonlinear potential flow (FNPF) solver with the native OpenFOAM incompressible ‘interFoam’ solver in a numerical wave tank (NWT). The coupling procedure for this new model, named IntegratedFoam, follows a domain decomposition approach in which an overlapping relaxation zone is utilised to implement a one-way coupling. Consequently, the method for transferring information is made simple and the coupling stable due to the primary advantage that each constituent solver has been developed in the same framework of OpenFOAM, and therefore, are both also based on the same numerical method, i.e., the finite-volume method (FVM). This means that only a method to calculate the volume fraction from the free-surface elevation needs to be implemented: the velocity and pressure are already calculated as part of the FNPF solution and can be transferred accordingly. In addition, existing advanced OpenFOAM functionalities can be used for the required interpolation—easily addressing the problem of nonconforming meshes. These functionalities then also allow for the easy implementation of an overlapping relaxation zone which is key to a stable coupling because it ensures that there is a smooth transition from the FNPF to interFoam solution whilst also absorbing any reflected waves in the NWT. The accuracy and efficiency of the new IntegratedFoam model are then systematically validated through two complex wave–structure interaction test cases: focused wave interaction with a fixed 3-D cylinder acting as a simplified monopile foundation and focused wave interaction with a 3-D wave energy converter (WEC) device. It is shown to produce accurate numerical solutions that agree well with existing numerical results and experimental data, all whilst significantly improving computational efficiency.

本文提出了一种新的波浪-结构相互作用综合水动力模拟框架。它是将基于有限体积的全非线性势流（FNPF）求解器与原生的OpenFOAM不可压缩“interFoam”求解器耦合在数值波槽（NWT）中开发的。这个名为IntegratedFoam的新模型的耦合过程遵循域分解方法，其中使用重叠松弛区来实现单向耦合。因此，由于每个组成求解器都是在OpenFOAM的同一框架中开发的，因此它们也基于相同的数值方法，即有限体积方法（FVM），因此使得传递信息的方法变得简单，耦合稳定。这意味着只需要实现一种从自由表面高程计算体积分数的方法：速度和压力已经作为FNPF解决方案的一部分计算出来，并且可以相应地进行传递。此外，现有的高级OpenFOAM功能可用于所需的插值-轻松解决网格不一致的问题。这些功能还允许轻松实现重叠松弛区，这是稳定耦合的关键，因为它确保了从FNPF到interFoam溶液的平滑过渡，同时也吸收了NWT中的任何反射波。然后，通过两个复杂的波-结构相互作用测试案例，系统地验证了新IntegratedFoam模型的准确性和效率：与固定的三维圆柱体作为简化的单桩基础的聚焦波相互作用，以及与三维波能转换器（WEC）装置的聚焦波相互作用。结果表明，所得到的数值解与已有的数值结果和实验数据吻合较好，同时显著提高了计算效率。

{"title":"A new integrated numerical wave tank in OpenFOAM for hydrodynamic modelling of offshore renewables","authors":"Ranjodh Rai , Zhihua Ma , Ling Qian , Wei Bai , Zaibin Lin","doi":"10.1016/j.apor.2025.104858","DOIUrl":"10.1016/j.apor.2025.104858","url":null,"abstract":"<div><div>This paper presents a new integrated hydrodynamic modelling framework for wave–structure interaction problems. It is developed by coupling a finite-volume-based fully nonlinear potential flow (FNPF) solver with the native OpenFOAM incompressible ‘interFoam’ solver in a numerical wave tank (NWT). The coupling procedure for this new model, named IntegratedFoam, follows a domain decomposition approach in which an overlapping relaxation zone is utilised to implement a one-way coupling. Consequently, the method for transferring information is made simple and the coupling stable due to the primary advantage that each constituent solver has been developed in the same framework of OpenFOAM, and therefore, are both also based on the same numerical method, i.e., the finite-volume method (FVM). This means that only a method to calculate the volume fraction from the free-surface elevation needs to be implemented: the velocity and pressure are already calculated as part of the FNPF solution and can be transferred accordingly. In addition, existing advanced OpenFOAM functionalities can be used for the required interpolation—easily addressing the problem of nonconforming meshes. These functionalities then also allow for the easy implementation of an overlapping relaxation zone which is key to a stable coupling because it ensures that there is a smooth transition from the FNPF to interFoam solution whilst also absorbing any reflected waves in the NWT. The accuracy and efficiency of the new IntegratedFoam model are then systematically validated through two complex wave–structure interaction test cases: focused wave interaction with a fixed 3-D cylinder acting as a simplified monopile foundation and focused wave interaction with a 3-D wave energy converter (WEC) device. It is shown to produce accurate numerical solutions that agree well with existing numerical results and experimental data, all whilst significantly improving computational efficiency.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104858"},"PeriodicalIF":4.4,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526202","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}

引用次数: 0

A generalised analytical solution for pipeline walking considering soil resistance as elastoplastic behaviour 考虑土阻力为弹塑性行为的管道行走的广义解析解

IF 4.4 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-11-12 DOI: 10.1016/j.apor.2025.104835

Yinghui Tian , Wanchao Wu , Mark J. Cassidy

This paper presents a generalised analytical solution for pipeline walking under cyclic temperature and internal pressure variations, incorporating elastoplastic soil resistance. The governing equations are formulated in incremental form, and a closed-form analytical solution is derived. Previously published analytical models that assume rigid plastic soil behaviour are shown to be a special case of this generalised framework, recovered by setting the elastic mobilisation distance to zero. A simplified mathematical expression for pipeline walking rate is obtained, enabling efficient predictions. Calculation examples based on realistic offshore conditions demonstrate the application of the solution in assessing the complete history of pipeline walking. Furthermore, a sensitivity analysis highlights the influence of key parameters on walking behaviour, providing insights for offshore pipeline design and stability assessment.

本文提出了考虑土壤弹塑性阻力的循环温度和内压变化下管道行走的广义解析解。控制方程以增量形式表示，并导出了封闭形式的解析解。以前发表的分析模型假设刚性塑性土壤的行为被证明是这种广义框架的特殊情况，通过将弹性动员距离设置为零来恢复。得到了管道行走速率的简化数学表达式，实现了高效的预测。基于实际海上条件的计算实例证明了该解决方案在评估管道行走完整历史中的应用。此外，灵敏度分析强调了关键参数对行走行为的影响，为海上管道设计和稳定性评估提供了见解。

引用次数: 0

Critical roles of mass, spring, and damping ratios in nonlinear energy sink vortex-induced vibrational control: CFD & optimization 质量、弹簧和阻尼比在非线性能量汇涡激振动控制中的关键作用：CFD与优化

IF 4.4 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-11-10 DOI: 10.1016/j.apor.2025.104852

Ahmed Abuelyamen , Mariam Nagi Amer , Ahmed K. Alkaabi , Saeed A. Alameri , Imran Afgan

Vortex-induced vibration (VIV) poses significant challenges in engineering. Structures subjected to fluid flows necessitate effective suppression mechanisms to avoid vibrations. This study investigates the ability of a nonlinear energy sink (NES) system to reduce VIV under a variety of reduced velocities (

U r

). Over

3, 000

scenarios were examined to assess the impact of NES properties; mass ratio (

β = 0.01 - 0.5

), spring ratio (

γ = 0.01 - 2.0

), and damping ratio (

ξ = 0.01 - 2.0

) on the vibrational response of structures using computational fluid dynamics (CFD) simulations utilizing Reynolds-averaged Navier–Stokes (

R A N S

) turbulence models. The numerical simulations were validated using experimental data demonstrating excellent agreement with the literature. Vibrational contour maps were developed from the CFD predictions over a wide range of

U r, β, γ, a n d ξ

. Our findings indicate that the process of tuning the NES parameters (β, γ, and ξ) can either diminish vibrational amplitudes (

A y / D

), or if not carefully optimized, can amplify them. With optimal NES parameter tuning, an amplitude reduction of

94 %

was found to be possible. Furthermore, Sobol sensitivity analysis was performed, which revealed that while

A y / D

highly depends on

U r

, proper tuning of the

β

in combination with

γ

is critical, especially in regimes where parameter interactions become significant. While global optimization is challenging, it is recommended that the optimized NES parameters for the lock-in region differ from those for the lower-branch vibration region.

涡激振动（VIV）是工程领域的一大难题。受流体流动影响的结构需要有效的抑制机制来避免振动。本文研究了非线性能量汇（NES）系统在不同减速速度（Ur）下降低涡激振动的能力。研究了超过3,000种方案，以评估新环境属性的影响；利用reynolds -average Navier-Stokes （RANS）湍流模型进行计算流体动力学（CFD）模拟，研究了质量比（β=0.01−0.5）、弹簧比（γ=0.01−2.0）和阻尼比（ξ=0.01−2.0）对结构振动响应的影响。用实验数据对数值模拟结果进行了验证，结果与文献结果非常吻合。振动等高线图是根据CFD预测在Ur，β，γ和ξ的广泛范围内开发的。我们的研究结果表明，调整NES参数（β， γ和ξ）的过程可以减小振动幅度（Ay/D），或者如果不仔细优化，可以放大它们。通过最优的NES参数调整，发现幅度降低94%是可能的。此外，Sobol敏感性分析显示，虽然Ay/D高度依赖于Ur，但适当调整β与γ的组合是至关重要的，特别是在参数相互作用变得重要的情况下。虽然全局优化具有挑战性，但建议锁定区域的优化NES参数与低分支振动区域的优化NES参数不同。

{"title":"Critical roles of mass, spring, and damping ratios in nonlinear energy sink vortex-induced vibrational control: CFD & optimization","authors":"Ahmed Abuelyamen , Mariam Nagi Amer , Ahmed K. Alkaabi , Saeed A. Alameri , Imran Afgan","doi":"10.1016/j.apor.2025.104852","DOIUrl":"10.1016/j.apor.2025.104852","url":null,"abstract":"<div><div>Vortex-induced vibration (VIV) poses significant challenges in engineering. Structures subjected to fluid flows necessitate effective suppression mechanisms to avoid vibrations. This study investigates the ability of a nonlinear energy sink (NES) system to reduce VIV under a variety of reduced velocities (<span><math><mrow><mi>U</mi><mi>r</mi></mrow></math></span>). Over <span><math><mrow><mn>3</mn><mo>,</mo><mn>000</mn></mrow></math></span> scenarios were examined to assess the impact of NES properties; mass ratio (<span><math><mrow><mi>β</mi><mo>=</mo><mn>0.01</mn><mo>−</mo><mn>0.5</mn></mrow></math></span>), spring ratio (<span><math><mrow><mi>γ</mi><mo>=</mo><mn>0.01</mn><mo>−</mo><mn>2.0</mn></mrow></math></span>), and damping ratio (<span><math><mrow><mi>ξ</mi><mo>=</mo><mn>0.01</mn><mo>−</mo><mn>2.0</mn></mrow></math></span>) on the vibrational response of structures using computational fluid dynamics (CFD) simulations utilizing Reynolds-averaged Navier–Stokes (<span><math><mrow><mi>R</mi><mi>A</mi><mi>N</mi><mi>S</mi></mrow></math></span>) turbulence models. The numerical simulations were validated using experimental data demonstrating excellent agreement with the literature. Vibrational contour maps were developed from the CFD predictions over a wide range of <span><math><mrow><mi>U</mi><mi>r</mi><mo>,</mo><mspace></mspace><mi>β</mi><mo>,</mo><mspace></mspace><mi>γ</mi><mo>,</mo><mspace></mspace><mi>a</mi><mi>n</mi><mi>d</mi><mspace></mspace><mi>ξ</mi></mrow></math></span>. Our findings indicate that the process of tuning the NES parameters (β, γ, and ξ) can either diminish vibrational amplitudes (<span><math><mrow><mi>A</mi><mi>y</mi><mo>/</mo><mi>D</mi></mrow></math></span>), or if not carefully optimized, can amplify them. With optimal NES parameter tuning, an amplitude reduction of <span><math><mrow><mn>94</mn><mo>%</mo></mrow></math></span> was found to be possible. Furthermore, Sobol sensitivity analysis was performed, which revealed that while <span><math><mrow><mi>A</mi><mi>y</mi><mo>/</mo><mi>D</mi></mrow></math></span> highly depends on <span><math><mrow><mi>U</mi><mi>r</mi></mrow></math></span>, proper tuning of the <span><math><mi>β</mi></math></span> in combination with <span><math><mi>γ</mi></math></span> is critical, especially in regimes where parameter interactions become significant. While global optimization is challenging, it is recommended that the optimized NES parameters for the lock-in region differ from those for the lower-branch vibration region.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104852"},"PeriodicalIF":4.4,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526207","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}

引用次数: 0

Nonlinear effects on wave elevation of a focused water wave group 聚焦水波群波浪高程的非线性效应

IF 4.4 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-11-10 DOI: 10.1016/j.apor.2025.104853

X. Feng , J. Chen , Z. Liu , Z. Zhang , Y. Li

Ocean extreme waves are of both scientific and engineering interests. These extreme waves pose great threats to the safety of coastal and offshore structures. They are highly nonlinear and transient in a real sea state. It is important to study their nonlinear effects for accurate prediction of them. In this study, a focused wave group is used to investigate the nonlinear properties in such transient extreme event experimentally and numerically. An experimental campaign is carried out in a large wave tank facility, and a fully nonlinear potential flow model is employed for numerical simulations. A phase-manipulation approach is applied on wave generation in order to extract clean higher harmonic wave elevations. Comparisons between the measurements and the numerical results show good agreements for higher harmonic elevations. The non-dimensional harmonic coefficients, based on a ‘Stokes-type’ harmonic structure, are found to increase gradually with the wave steepness. This suggests that the classical Stokes model might be used for nonlinear wave group prediction, given proper harmonic coefficients. To further investigate the nonlinear effects, the asymmetric properties of the wave profiles near focusing are explored by analysing the preceding and following wave crests. Clear nonlinearity is demonstrated by evaluating the wave envelope height and group bandwidth.

海洋极端波浪具有科学和工程双重意义。这些极端的海浪对海岸和近海建筑的安全构成了巨大的威胁。它们在实际海况下是高度非线性和瞬态的。研究它们的非线性效应对于准确预测它们具有重要意义。本文采用聚焦波群对瞬态极端事件的非线性特性进行了实验和数值研究。在大型波浪槽设施中进行了实验，采用全非线性势流模型进行了数值模拟。为了提取干净的高次谐波高程，在波形产生中采用了相位处理方法。实测结果与数值结果比较表明，在较高的谐波高程下，实测结果与数值结果吻合较好。基于stokes型谐波结构的无量纲谐波系数随着波浪陡度的增大而逐渐增大。这表明，在给定适当的谐波系数的情况下，经典Stokes模型可以用于非线性波群预测。为了进一步研究非线性效应，通过对前后波峰的分析，探讨了聚焦附近波廓线的不对称特性。通过对包络波高度和群带宽的评估，证明了明显的非线性。

{"title":"Nonlinear effects on wave elevation of a focused water wave group","authors":"X. Feng , J. Chen , Z. Liu , Z. Zhang , Y. Li","doi":"10.1016/j.apor.2025.104853","DOIUrl":"10.1016/j.apor.2025.104853","url":null,"abstract":"<div><div>Ocean extreme waves are of both scientific and engineering interests. These extreme waves pose great threats to the safety of coastal and offshore structures. They are highly nonlinear and transient in a real sea state. It is important to study their nonlinear effects for accurate prediction of them. In this study, a focused wave group is used to investigate the nonlinear properties in such transient extreme event experimentally and numerically. An experimental campaign is carried out in a large wave tank facility, and a fully nonlinear potential flow model is employed for numerical simulations. A phase-manipulation approach is applied on wave generation in order to extract clean higher harmonic wave elevations. Comparisons between the measurements and the numerical results show good agreements for higher harmonic elevations. The non-dimensional harmonic coefficients, based on a ‘Stokes-type’ harmonic structure, are found to increase gradually with the wave steepness. This suggests that the classical Stokes model might be used for nonlinear wave group prediction, given proper harmonic coefficients. To further investigate the nonlinear effects, the asymmetric properties of the wave profiles near focusing are explored by analysing the preceding and following wave crests. Clear nonlinearity is demonstrated by evaluating the wave envelope height and group bandwidth.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104853"},"PeriodicalIF":4.4,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526205","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}

引用次数: 0

Automatic Mooring-Line-Failure Detection Using Hull Motion Sensors and Machine Learning (ML) for 15MW Floating Offshore Wind Turbines (FOWTs) 基于船体运动传感器和机器学习（ML）的15MW浮式海上风力涡轮机系泊线故障自动检测

IF 4.4 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-11-07 DOI: 10.1016/j.apor.2025.104844

JeongYong Park , Ikjae Lee , MooHyun Kim , Chungkuk Jin , Ipsita Mishra , D. Todd Griffith , Mario A. Rotea

Mooring line failure in Floating Offshore Wind Turbines (FOWTs) threatens safety, power production, and nearby structures. This study develops an automated detection framework that combines hull motion sensors with machine learning (ML). A synthetic dataset for the 15MW VolturnUS-S semi-submersible FOWT was created using OpenFAST under intact and failed mooring conditions across 79 wind and wave scenarios. The mean and standard deviation of six degree of freedom (6DOF) motions including surge, sway, heave, roll, pitch, and yaw were used as input features. Different sensor configurations such as inertial measurement units (IMU) and differential GPS (DGPS) were tested under added noise. Artificial neural networks (ANN), random forests (RF), and support vector machines (SVM) were evaluated with optimized hyperparameters. All models achieved excellent accuracy, with RF performing best. However, using raw IMU signals without displacement conversion reduces prediction accuracy due to missing mean offset information. The results demonstrate a reliable approach for near-real-time mooring-integrity monitoring that improves safety while reducing reliance on expensive equipment.

浮式海上风力发电机组的系泊缆绳故障威胁着安全、电力生产和附近结构。本研究开发了一种将船体运动传感器与机器学习（ML）相结合的自动检测框架。15MW VolturnUS-S半潜式FOWT的合成数据集使用OpenFAST在79种风浪情况下完整和失效系泊条件下创建。六自由度（6DOF）运动（包括浪涌、摇摆、升沉、翻滚、俯仰和偏航）的均值和标准差作为输入特征。在附加噪声条件下，对惯性测量单元（IMU）和差分GPS （DGPS）等不同传感器配置进行了测试。利用优化后的超参数对人工神经网络（ANN）、随机森林（RF）和支持向量机（SVM）进行评价。所有模型都实现了出色的精度，其中射频性能最佳。然而，使用未经位移转换的原始IMU信号会由于缺少平均偏移信息而降低预测精度。结果证明了一种可靠的近实时系泊完整性监测方法，可以提高安全性，同时减少对昂贵设备的依赖。

{"title":"Automatic Mooring-Line-Failure Detection Using Hull Motion Sensors and Machine Learning (ML) for 15MW Floating Offshore Wind Turbines (FOWTs)","authors":"JeongYong Park , Ikjae Lee , MooHyun Kim , Chungkuk Jin , Ipsita Mishra , D. Todd Griffith , Mario A. Rotea","doi":"10.1016/j.apor.2025.104844","DOIUrl":"10.1016/j.apor.2025.104844","url":null,"abstract":"<div><div>Mooring line failure in Floating Offshore Wind Turbines (FOWTs) threatens safety, power production, and nearby structures. This study develops an automated detection framework that combines hull motion sensors with machine learning (ML). A synthetic dataset for the 15MW VolturnUS-S semi-submersible FOWT was created using OpenFAST under intact and failed mooring conditions across 79 wind and wave scenarios. The mean and standard deviation of six degree of freedom (6DOF) motions including surge, sway, heave, roll, pitch, and yaw were used as input features. Different sensor configurations such as inertial measurement units (IMU) and differential GPS (DGPS) were tested under added noise. Artificial neural networks (ANN), random forests (RF), and support vector machines (SVM) were evaluated with optimized hyperparameters. All models achieved excellent accuracy, with RF performing best. However, using raw IMU signals without displacement conversion reduces prediction accuracy due to missing mean offset information. The results demonstrate a reliable approach for near-real-time mooring-integrity monitoring that improves safety while reducing reliance on expensive equipment.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104844"},"PeriodicalIF":4.4,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145463565","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}

引用次数: 0

Operational coastal ocean modelling for tidal stream turbine arrays 潮汐流涡轮机阵列的近海操作模拟

IF 4.4 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-11-07 DOI: 10.1016/j.apor.2025.104847

Nguyen Q. Chien , Connor Jordan , Emils Brazovskis , Brian Sellar , João Ribeiro , Adélio Silva , Athanasios Angeloudis

Operational ocean models are widely applied for Earth and ocean observation for real-time predictions of ocean processes at large scales. Adaptations of these systems could cater more specific engineering and finer, metre-scale, applications. With this in mind, we consider the operational modelling for tidal stream turbine arrays, where multiple scales of coastal ocean hydrodynamics must be reconciled to facilitate the conversion of hydrokinetic energy. In monitoring an array’s performance, impact, and ocean interactions, an operational modelling system must resolve both metocean forcing from tens of kilometres away and fine-scale flow patterns around individual turbines. This study demonstrates the functionality, utility, and sensitivity of such a system to support the design of tidal arrays. We focus on a turbine array operating in the Pentland Firth, Scotland. The tidal array operational model is designed to operate in real-time, allows web clients to ingest data, and returns design data summarised and visualised in a web dashboard, alongside a series of appropriate metrics. We note significant trade-offs with respect to the modelling setup balancing resolution and accuracy against measured data. We also demonstrate the value of multi-scale ocean modelling from an operational perspective, which focuses computational effort where it is most needed to deliver near-real-time information reliably.

业务海洋模式广泛应用于地球和海洋观测，用于大尺度海洋过程的实时预测。这些系统的调整可以满足更具体的工程和更精细的、米级的应用。考虑到这一点，我们考虑潮汐流涡轮机阵列的操作建模，其中必须协调沿海海洋水动力学的多个尺度，以促进水动能的转换。在监测阵列的性能、影响和海洋相互作用时，操作建模系统必须同时解决来自几十公里外的海洋强迫和单个涡轮机周围的精细流动模式。本研究展示了该系统的功能性、实用性和灵敏度，以支持潮汐阵的设计。我们专注于在苏格兰Pentland Firth运行的涡轮机阵列。潮汐阵列操作模型旨在实时操作，允许web客户端摄取数据，并在web仪表板中返回汇总和可视化的设计数据，以及一系列适当的指标。我们注意到在建模设置平衡分辨率和测量数据的准确性方面的重大权衡。我们还从操作角度展示了多尺度海洋建模的价值，它将计算工作集中在最需要可靠地提供近实时信息的地方。

{"title":"Operational coastal ocean modelling for tidal stream turbine arrays","authors":"Nguyen Q. Chien , Connor Jordan , Emils Brazovskis , Brian Sellar , João Ribeiro , Adélio Silva , Athanasios Angeloudis","doi":"10.1016/j.apor.2025.104847","DOIUrl":"10.1016/j.apor.2025.104847","url":null,"abstract":"<div><div>Operational ocean models are widely applied for Earth and ocean observation for real-time predictions of ocean processes at large scales. Adaptations of these systems could cater more specific engineering and finer, metre-scale, applications. With this in mind, we consider the operational modelling for tidal stream turbine arrays, where multiple scales of coastal ocean hydrodynamics must be reconciled to facilitate the conversion of hydrokinetic energy. In monitoring an array’s performance, impact, and ocean interactions, an operational modelling system must resolve both metocean forcing from tens of kilometres away and fine-scale flow patterns around individual turbines. This study demonstrates the functionality, utility, and sensitivity of such a system to support the design of tidal arrays. We focus on a turbine array operating in the Pentland Firth, Scotland. The tidal array operational model is designed to operate in real-time, allows web clients to ingest data, and returns design data summarised and visualised in a web dashboard, alongside a series of appropriate metrics. We note significant trade-offs with respect to the modelling setup balancing resolution and accuracy against measured data. We also demonstrate the value of multi-scale ocean modelling from an operational perspective, which focuses computational effort where it is most needed to deliver near-real-time information reliably.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104847"},"PeriodicalIF":4.4,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145463514","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}

引用次数: 0

Rapid evaluation of steady-turning motion parameters for a dual-tail propulsion underwater glider 双尾推进水下滑翔机稳定转向运动参数的快速评估

IF 4.4 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-11-07 DOI: 10.1016/j.apor.2025.104846

Chaoming Bao, Jingqi Zhong, Daiyu Zhang, Daxing Zeng, Qian Liu

The evaluation of steady turning performance for dual-tail propulsion underwater gliders typically relies on high-fidelity unsteady CFD simulations, which remain computationally prohibitive for control optimization and multi-scenario analysis. To overcome this limitation, this paper proposes a rapid prediction framework integrating Kriging surrogate modeling with dynamic equilibrium constraints. The proposed method employs a physics-informed decoupling strategy that isolates the hydrodynamic behavior of the hull from the thrust generation of the propellers. Since these are governed by distinct physical mechanisms and operate at different spatial scales, the decoupling strategy enables efficient and targeted steady-state CFD analysis for each component subsystem. Latin Hypercube Sampling (LHS) is used to generate training data for highly accurate Kriging models, which are subsequently coupled with the glider’s balance equations to form a bidirectional solution system. The forward mode predicts turning performance from control inputs, whereas the inverse mode identifies propeller speeds required for desired trajectories. Validation via fully-coupled 6-DOF unsteady CFD simulations confirms that the framework achieves prediction errors below 10% for key turning parameters while improving computational efficiency by over an order of magnitude. The method provides an effective tool for rapid maneuverability evaluation, control system design, and real-time path planning in dual-tail propulsion underwater gliders.

双尾推进水下滑翔机的稳定转向性能评估通常依赖于高保真的非定常CFD模拟，这在控制优化和多场景分析中仍然存在计算限制。为了克服这一局限性，本文提出了一种结合Kriging代理模型和动态平衡约束的快速预测框架。所提出的方法采用了一种物理解耦策略，将船体的水动力行为与螺旋桨的推力产生分离开来。由于它们受不同的物理机制控制，并且在不同的空间尺度上运行，因此解耦策略可以对每个组件子系统进行高效和有针对性的稳态CFD分析。拉丁超立方体采样（LHS）用于生成高精度克里格模型的训练数据，随后将其与滑翔机的平衡方程耦合形成双向解系统。正向模式根据控制输入预测转弯性能，而逆模式则识别所需轨迹所需的螺旋桨速度。通过全耦合六自由度非定常CFD模拟验证，该框架对关键转弯参数的预测误差低于10%，同时将计算效率提高了一个数量级以上。该方法为双尾推进水下滑翔机的快速机动性评估、控制系统设计和实时路径规划提供了有效工具。

{"title":"Rapid evaluation of steady-turning motion parameters for a dual-tail propulsion underwater glider","authors":"Chaoming Bao, Jingqi Zhong, Daiyu Zhang, Daxing Zeng, Qian Liu","doi":"10.1016/j.apor.2025.104846","DOIUrl":"10.1016/j.apor.2025.104846","url":null,"abstract":"<div><div>The evaluation of steady turning performance for dual-tail propulsion underwater gliders typically relies on high-fidelity unsteady CFD simulations, which remain computationally prohibitive for control optimization and multi-scenario analysis. To overcome this limitation, this paper proposes a rapid prediction framework integrating Kriging surrogate modeling with dynamic equilibrium constraints. The proposed method employs a physics-informed decoupling strategy that isolates the hydrodynamic behavior of the hull from the thrust generation of the propellers. Since these are governed by distinct physical mechanisms and operate at different spatial scales, the decoupling strategy enables efficient and targeted steady-state CFD analysis for each component subsystem. Latin Hypercube Sampling (LHS) is used to generate training data for highly accurate Kriging models, which are subsequently coupled with the glider’s balance equations to form a bidirectional solution system. The forward mode predicts turning performance from control inputs, whereas the inverse mode identifies propeller speeds required for desired trajectories. Validation via fully-coupled 6-DOF unsteady CFD simulations confirms that the framework achieves prediction errors below 10% for key turning parameters while improving computational efficiency by over an order of magnitude. The method provides an effective tool for rapid maneuverability evaluation, control system design, and real-time path planning in dual-tail propulsion underwater gliders.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104846"},"PeriodicalIF":4.4,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145463515","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}

引用次数: 0

Numerical study of the wake evolution behind a shaftless pump-jet propulsor 无轴泵喷推进器尾迹演化的数值研究

IF 4.4 2区工程技术 Q1 ENGINEERING, OCEAN

Applied Ocean Research

Pub Date : 2025-11-06 DOI: 10.1016/j.apor.2025.104854

Peng Li , Jinlei Mu , Zhanzhi Wang , Chao Wang

To identify the evolution of the vortices hidden in the wake behind a shaft-less pump-jet propulsor, the delayed detached eddy simulation is performed on a computational domain comprising 22.8 million cells to analyze the wake evolution behind a shaftless pump-jet propulsor under various uniform freestream conditions. Convergence analysis and validation against available data confirm the reliability of the numerical approach. Vortex structures are visualized by using the Q-criterion iso-surfaces, while instantaneous and phase-locked averaged flow variables are employed to elucidate the detailed wake dynamics. The numerical results reveal a novel wake evolution mechanism characterized by two wake transition points: Before the first wake transition point, duct-induced vortices rapidly dissipate, leaving the wake dominated by blade/stator trailing vortices and the hub vortex. Between the two wake transition points, the wake is primarily governed by the scythe-shaped vortices (evolved from earlier vortex structures) and the persistent hub vortex. Beyond the second wake transition point, the legs of the scythe-shaped vortices merge with each other and detach from the knee region, triggering instability and fragmenting into smaller-scale structures, which eventually turn into the far-field wake. This study provides valuable insights for the hydrodynamic optimization of the shaftless pump-jet propulsor.

为了识别无轴泵喷推进器后尾迹中隐藏的涡的演变，在2280万单元的计算域上进行了延迟分离涡模拟，分析了不同均匀自由流条件下无轴泵喷推进器后尾迹的演变。收敛分析和对现有数据的验证验证了数值方法的可靠性。采用q准则等面来可视化旋涡结构，同时采用瞬时和锁相平均流动变量来阐明详细的尾迹动力学。数值结果揭示了一种新的以两个尾迹过渡点为特征的尾迹演化机制：在第一个尾迹过渡点之前，导管诱导的涡迅速消散，留下由叶片/静叶尾涡和轮毂涡主导的尾迹；在两个尾流过渡点之间，尾流主要由镰刀形涡（由早期的涡结构演变而来）和持续的轮毂涡控制。在第二个尾流过渡点之外，镰刀状漩涡的腿彼此合并并从膝盖区域分离，引发不稳定并分裂成更小的结构，最终变成远场尾流。该研究为无轴泵喷推进器的水动力优化提供了有价值的见解。

{"title":"Numerical study of the wake evolution behind a shaftless pump-jet propulsor","authors":"Peng Li , Jinlei Mu , Zhanzhi Wang , Chao Wang","doi":"10.1016/j.apor.2025.104854","DOIUrl":"10.1016/j.apor.2025.104854","url":null,"abstract":"<div><div>To identify the evolution of the vortices hidden in the wake behind a shaft-less pump-jet propulsor, the delayed detached eddy simulation is performed on a computational domain comprising 22.8 million cells to analyze the wake evolution behind a shaftless pump-jet propulsor under various uniform freestream conditions. Convergence analysis and validation against available data confirm the reliability of the numerical approach. Vortex structures are visualized by using the <em>Q</em>-criterion iso-surfaces, while instantaneous and phase-locked averaged flow variables are employed to elucidate the detailed wake dynamics. The numerical results reveal a novel wake evolution mechanism characterized by two wake transition points: Before the first wake transition point, duct-induced vortices rapidly dissipate, leaving the wake dominated by blade/stator trailing vortices and the hub vortex. Between the two wake transition points, the wake is primarily governed by the scythe-shaped vortices (evolved from earlier vortex structures) and the persistent hub vortex. Beyond the second wake transition point, the legs of the scythe-shaped vortices merge with each other and detach from the knee region, triggering instability and fragmenting into smaller-scale structures, which eventually turn into the far-field wake. This study provides valuable insights for the hydrodynamic optimization of the shaftless pump-jet propulsor.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"165 ","pages":"Article 104854"},"PeriodicalIF":4.4,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145463516","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}

引用次数: 0