Pub Date : 2025-02-01DOI: 10.1016/j.apor.2025.104460
Yuefeng Wu , Qinghe Zhang , Ziming Liu , Chao Ji
In the surf zone, breaking waves generate an air-entraining turbulent region ahead of the wave crest, known as the wave roller, which plays a crucial role in nearshore dynamics. Using image-based techniques, measurements of wave roller areas and their relationships with wave properties were obtained in a laboratory wave tank. The results indicated a positive correlation between wave roller area and both wave height and wavelength. The ratio of roller area to the product of wave height and wavelength varied with factors such as slope, wave steepness, and degree of roller development. A predictive formula for roller area was then developed using a genetic programming model. Furthermore, the fraction of breaking dissipation feeding wave roller energy revealed a gradual decrease along the direction of wave propagation in the surf zone. A substantial portion of breaking dissipation feeds into roller energy in the outer surf zone, while wave rollers stabilize and draw minimal energy from breaking dissipation in the inner surf zone. The measurements and analysis in this study could enhance the understanding of momentum flux caused by wave rollers, improving numerical predictions of hydrodynamics and material transport in the nearshore ocean.
{"title":"Experimental investigation on wave roller area evolution in the surf zone","authors":"Yuefeng Wu , Qinghe Zhang , Ziming Liu , Chao Ji","doi":"10.1016/j.apor.2025.104460","DOIUrl":"10.1016/j.apor.2025.104460","url":null,"abstract":"<div><div>In the surf zone, breaking waves generate an air-entraining turbulent region ahead of the wave crest, known as the wave roller, which plays a crucial role in nearshore dynamics. Using image-based techniques, measurements of wave roller areas and their relationships with wave properties were obtained in a laboratory wave tank. The results indicated a positive correlation between wave roller area and both wave height and wavelength. The ratio of roller area to the product of wave height and wavelength varied with factors such as slope, wave steepness, and degree of roller development. A predictive formula for roller area was then developed using a genetic programming model. Furthermore, the fraction of breaking dissipation feeding wave roller energy revealed a gradual decrease along the direction of wave propagation in the surf zone. A substantial portion of breaking dissipation feeds into roller energy in the outer surf zone, while wave rollers stabilize and draw minimal energy from breaking dissipation in the inner surf zone. The measurements and analysis in this study could enhance the understanding of momentum flux caused by wave rollers, improving numerical predictions of hydrodynamics and material transport in the nearshore ocean.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"155 ","pages":"Article 104460"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Understanding the condition of a ship during operation is crucial for ensuring hull safety. This can be achieved either by directly monitoring the ship's hull or by using response estimation models when the wave field is known. Developing a method for real-time estimation of wave profiles and subsequent ship responses, especially in short-crested irregular waves that closely resemble real sea conditions, is essential. This study aims to develop and validate a Kalman Filter (KF) technique to estimate wave profiles encountered by a ship and unmeasured ship responses from measured response signals in short-crested irregular waves. A tank testing with a scaled model is performed in short-crested irregular waves to validate the method. The wave profiles are represented as a linear superposition of elementary waves, assuming linearity in both the waves and ship responses. The wave amplitudes of these elementary waves are modeled as state variables and estimated in real-time using the KF technique. The results demonstrate that unmeasured ship responses can also be predicted with good accuracy by combining the estimated wave profiles with transfer functions. This research extends the authors’ previous work, which applied the KF technique to long-crested irregular waves. In this study, short-crested irregular waves are modeled using a double-summation method, and a new method for calculating wave directional spectra is proposed. This method accounts for interference among waves of the same frequency but different wave encounter angles.
{"title":"Kalman filter technique for estimating encountered wave profiles and unmeasured ship responses using measurement data in short-crested irregular waves","authors":"Yusuke Komoriyama , Kazuhiro Iijima , Hidetaka Houtani , Akira Tatsumi , Masahiko Fujikubo","doi":"10.1016/j.apor.2025.104453","DOIUrl":"10.1016/j.apor.2025.104453","url":null,"abstract":"<div><div>Understanding the condition of a ship during operation is crucial for ensuring hull safety. This can be achieved either by directly monitoring the ship's hull or by using response estimation models when the wave field is known. Developing a method for real-time estimation of wave profiles and subsequent ship responses, especially in short-crested irregular waves that closely resemble real sea conditions, is essential. This study aims to develop and validate a Kalman Filter (KF) technique to estimate wave profiles encountered by a ship and unmeasured ship responses from measured response signals in short-crested irregular waves. A tank testing with a scaled model is performed in short-crested irregular waves to validate the method. The wave profiles are represented as a linear superposition of elementary waves, assuming linearity in both the waves and ship responses. The wave amplitudes of these elementary waves are modeled as state variables and estimated in real-time using the KF technique. The results demonstrate that unmeasured ship responses can also be predicted with good accuracy by combining the estimated wave profiles with transfer functions. This research extends the authors’ previous work, which applied the KF technique to long-crested irregular waves. In this study, short-crested irregular waves are modeled using a double-summation method, and a new method for calculating wave directional spectra is proposed. This method accounts for interference among waves of the same frequency but different wave encounter angles.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"155 ","pages":"Article 104453"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.apor.2025.104434
Lingxi Han , Lintao Zhou , Maria Mukhtar , A-Man Zhang , Rui Han , Shuai Li
This study examines the impact of hydrostatic pressure on the dynamics of underwater explosion bubbles near a steel plate through numerical and experimental studies. We conduct underwater explosion experiments in a pressure tank, altering the air pressure within the tank using a pressure pump to change the hydrostatic pressure around the bubbles. The interaction between the bubbles and the plate is recorded with a high-speed camera, and we extract and analyze the jet velocity, bubble radius, and plate displacement as functions of hydrostatic pressure. Building on this, we design a numerical framework that encompasses hydrostatic pressures varying from 0.2 MPa to 20 MPa and dimensionless bubble-plate standoff parameters from 0.6 to 2.5 for a more thorough investigation on the bubble-plate interaction. We find that both the maximum jet velocity and the maximum jet volume exhibit scaling relationships with hydrostatic pressure when MPa. Additionally, the dimensionless maximum jet volume shows a non-monotonic relationship with , depending on the degree of bubble-plate interaction at the moment of jet impact. Across a certain span, the maximum plate displacement also follows a scaling relationship with , where the exponent differs according to . This work is intended to offer a foundation for the study of underwater explosion bubble dynamics and fluid–structure interaction characteristics under high hydrostatic pressure or deep water environments.
{"title":"Influence of hydrostatic pressure on underwater explosion bubble-plate interaction","authors":"Lingxi Han , Lintao Zhou , Maria Mukhtar , A-Man Zhang , Rui Han , Shuai Li","doi":"10.1016/j.apor.2025.104434","DOIUrl":"10.1016/j.apor.2025.104434","url":null,"abstract":"<div><div>This study examines the impact of hydrostatic pressure on the dynamics of underwater explosion bubbles near a steel plate through numerical and experimental studies. We conduct underwater explosion experiments in a pressure tank, altering the air pressure within the tank using a pressure pump to change the hydrostatic pressure around the bubbles. The interaction between the bubbles and the plate is recorded with a high-speed camera, and we extract and analyze the jet velocity, bubble radius, and plate displacement as functions of hydrostatic pressure. Building on this, we design a numerical framework that encompasses hydrostatic pressures varying from 0.2 MPa to 20 MPa and dimensionless bubble-plate standoff parameters <span><math><mi>γ</mi></math></span> from 0.6 to 2.5 for a more thorough investigation on the bubble-plate interaction. We find that both the maximum jet velocity and the maximum jet volume exhibit scaling relationships with hydrostatic pressure <span><math><msub><mrow><mi>p</mi></mrow><mrow><mi>∞</mi></mrow></msub></math></span> when <span><math><mrow><msub><mrow><mi>p</mi></mrow><mrow><mi>∞</mi></mrow></msub><mo>></mo><mn>1</mn></mrow></math></span> MPa. Additionally, the dimensionless maximum jet volume shows a non-monotonic relationship with <span><math><mi>γ</mi></math></span>, depending on the degree of bubble-plate interaction at the moment of jet impact. Across a certain span, the maximum plate displacement also follows a scaling relationship with <span><math><msub><mrow><mi>p</mi></mrow><mrow><mi>∞</mi></mrow></msub></math></span>, where the exponent differs according to <span><math><mi>γ</mi></math></span>. This work is intended to offer a foundation for the study of underwater explosion bubble dynamics and fluid–structure interaction characteristics under high hydrostatic pressure or deep water environments.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"155 ","pages":"Article 104434"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143175794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research presents a method for analyzing the Remaining Useful Life (RUL) of pipelines impacted by corrosion defects through the integration of Latin Hypercube Sampling (LHS), Finite Element Analysis (FEA), and Machine Learning (ML). A dataset consisting of 200 samples and 8 random variables is generated, representing various pipeline and corrosion defect specifications. Finite element modeling is performed using ABAQUS software and Python scripting to calculate the Failure Pressure and failure Maximum Von-Mises Stress (MVMS) under varying conditions of longitudinal spacing () and Internal Pressure (IP). This model generates a dataset that includes internal pressure, longitudinal spacing, and other relevant variables for the training and evaluation of ML models. Model performance is assessed through grid search and overfitting checks. A corrosion growth algorithm is incorporated to update input data dynamically, allowing for the prediction of future MVMS values and associated failure probabilities. The Probability of Failure (POF) is calculated, and Probability Density Functions (PDFs) for failure pressure are analyzed using standard distributions and Kolmogorov-Smirnov tests to identify the most accurate model. This approach provides a robust framework for predicting RUL by evaluating pipeline failures and probabilistic failure pressure over time, contributing valuable insights into the reliability and safety of pipeline systems under various conditions and time intervals.
{"title":"Data-driven remaining useful life estimation of subsea pipelines under effect of interacting corrosion defects","authors":"Soheyl Hosseinzadeh, Mohammadreza Bahaari, Mohsen Abyani, Milad Taheri","doi":"10.1016/j.apor.2025.104438","DOIUrl":"10.1016/j.apor.2025.104438","url":null,"abstract":"<div><div>This research presents a method for analyzing the Remaining Useful Life (RUL) of pipelines impacted by corrosion defects through the integration of Latin Hypercube Sampling (LHS), Finite Element Analysis (FEA), and Machine Learning (ML). A dataset consisting of 200 samples and 8 random variables is generated, representing various pipeline and corrosion defect specifications. Finite element modeling is performed using ABAQUS software and Python scripting to calculate the Failure Pressure and failure Maximum Von-Mises Stress (MVMS) under varying conditions of longitudinal spacing (<span><math><msub><mi>S</mi><mi>l</mi></msub></math></span>) and Internal Pressure (IP). This model generates a dataset that includes internal pressure, longitudinal spacing, and other relevant variables for the training and evaluation of ML models. Model performance is assessed through grid search and overfitting checks. A corrosion growth algorithm is incorporated to update input data dynamically, allowing for the prediction of future MVMS values and associated failure probabilities. The Probability of Failure (POF) is calculated, and Probability Density Functions (PDFs) for failure pressure are analyzed using standard distributions and Kolmogorov-Smirnov tests to identify the most accurate model. This approach provides a robust framework for predicting RUL by evaluating pipeline failures and probabilistic failure pressure over time, contributing valuable insights into the reliability and safety of pipeline systems under various conditions and time intervals.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"155 ","pages":"Article 104438"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.apor.2025.104443
Cen Hang , Junning Pan , Liehong Ju , Biyao Zhai , Fan Yang , Dongmei Xie
Mangroves have notable wave attenuation capabilities, crucial for protecting coastal ecosystems. Most studies have focused on Rhizophora, particularly its complex aerial root systems, with limited research on Kandelia obovata, a widespread species characterized by short roots, radiating branches, and large canopies. To address this gap, wave attenuation by juvenile and mature Kandelia obovata, both with and without canopy, was investigated using wave flume experiments. The wave attenuation equation was modified to account for the complex mangrove morphology. The effective bulk drag coefficient of the entire vegetation , the elastic branch and flexible canopy were calculated. The results highlight the wave energy attenuation capabilities of flexible canopy in both mature and juvenile cases.Even sparse canopy of juvenile mangroves can produce wave attenuation comparable to that of mature tree branches. Juvenile mangroves exhibit acceptable energy dissipation primarily due to their canopies, but only at low water levels. Both branches and canopies of mature mangroves significantly attenuate waves, but as water level increases, the canopy gradually dominates. A new parameter, the hydraulic length scale , was proposed to predict the wave damping factor β. A new characteristic length scale hydrodynamic diameter was used to calculate the vegetation Reynolds number and the Keulegan-Carpenter number . Principal component analysis (PCA) indicated that combining and best predicts , with Re alone being the second-best. While correlates with , the underlying mechanism of this relationship may be complex and requires further research. The adaptability of the theoretical model for emergent vegetation is also explored. This study may contribute to the design of eco-coastal defenses using mangroves for protection.
{"title":"Wave attenuation by juvenile and mature mangrove Kandelia Obovata with flexible canopies","authors":"Cen Hang , Junning Pan , Liehong Ju , Biyao Zhai , Fan Yang , Dongmei Xie","doi":"10.1016/j.apor.2025.104443","DOIUrl":"10.1016/j.apor.2025.104443","url":null,"abstract":"<div><div>Mangroves have notable wave attenuation capabilities, crucial for protecting coastal ecosystems. Most studies have focused on <em>Rhizophora,</em> particularly its complex aerial root systems, with limited research on <em>Kandelia obovata</em>, a widespread species characterized by short roots, radiating branches, and large canopies. To address this gap, wave attenuation by juvenile and mature <em>Kandelia obovata</em>, both with and without canopy, was investigated using wave flume experiments. The wave attenuation equation was modified to account for the complex mangrove morphology. The effective bulk drag coefficient of the entire vegetation <span><math><msub><mi>C</mi><mi>D</mi></msub></math></span>, the elastic branch <span><math><mrow><mi>C</mi><msubsup><mrow></mrow><mrow><mi>D</mi><mo>,</mo><mi>b</mi></mrow><mo>′</mo></msubsup></mrow></math></span> and flexible canopy <span><math><mrow><mi>C</mi><msubsup><mrow></mrow><mrow><mi>D</mi><mo>,</mo><mi>c</mi></mrow><mo>′</mo></msubsup></mrow></math></span> were calculated. The results highlight the wave energy attenuation capabilities of flexible canopy in both mature and juvenile cases.Even sparse canopy of juvenile mangroves can produce wave attenuation comparable to that of mature tree branches. Juvenile mangroves exhibit acceptable energy dissipation primarily due to their canopies, but only at low water levels. Both branches and canopies of mature mangroves significantly attenuate waves, but as water level increases, the canopy gradually dominates. A new parameter, the hydraulic length scale <span><math><mrow><mi>H</mi><mi>L</mi></mrow></math></span>, was proposed to predict the wave damping factor <em>β</em>. A new characteristic length scale hydrodynamic diameter <span><math><msub><mi>D</mi><mi>e</mi></msub></math></span> was used to calculate the vegetation Reynolds number <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span> and the Keulegan-Carpenter number <span><math><mrow><mi>K</mi><mi>C</mi></mrow></math></span>. Principal component analysis (PCA) indicated that combining <span><math><mrow><mi>R</mi><mi>e</mi></mrow></math></span> and <span><math><mrow><mi>K</mi><mi>C</mi></mrow></math></span> best predicts <span><math><msub><mi>C</mi><mi>D</mi></msub></math></span>, with <em>Re</em> alone being the second-best. While <span><math><mrow><mi>C</mi><msup><mi>a</mi><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>3</mn></mrow></msup></mrow></math></span> correlates with <span><math><mrow><mi>C</mi><msubsup><mrow></mrow><mrow><mi>D</mi><mo>,</mo><mi>c</mi></mrow><mo>′</mo></msubsup></mrow></math></span>, the underlying mechanism of this relationship may be complex and requires further research. The adaptability of the theoretical model for emergent vegetation is also explored. This study may contribute to the design of eco-coastal defenses using mangroves for protection.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"155 ","pages":"Article 104443"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143174568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.apor.2025.104441
Shimin Yu , Edward Ransley , Ling Qian , Yang Zhou , Scott Brown , Deborah Greaves , Martyn Hann , Anna Holcombe , Emma Edwards , Tom Tosdevin , Sudhir Jagdale , Qian Li , Yi Zhang , Ningbo Zhang , Shiqiang Yan , Qingwei Ma , Bonaventura Tagliafierro , Salvatore Capasso , Iván Martínez-Estévez , Malin Göteman , Javier L. Lara
This paper summarises the work conducted within the 1st FOWT (Floating Offshore Wind Turbine) Comparative Study organised by the EPSRC (UK) ‘Extreme loading on FOWTs under complex environmental conditions’ and ‘Collaborative computational project on wave structure interaction (CCP-WSI)’ projects. The hydrodynamic response of a FOWT support structure is simulated with a range of numerical models based on potential theory, Morison equation, Navier-Stokes solvers and hybrid methods coupling different flow solvers. A series of load cases including the static equilibrium tests, free decay tests, operational and extreme focused wave cases are considered for the UMaine VolturnUS-S semi-submersible platform, and the results from 17 contributions are analysed and compared with each other and against the experimental data from a 1:70 scale model test performed in the COAST Laboratory Ocean Basin at the University of Plymouth. It is shown that most numerical models can predict similar results for the heave response, but significant discrepancies exist in the prediction of the surge and pitch responses as well as the mooring line loads. For the extreme focused wave case, while both Navier–Stokes and potential flow base models tend to produce larger errors in terms of the root mean squared error than the operational focused wave case, the Navier-Stokes based models generally perform better. Given the fact that variations in the solutions (sometimes large) also present in the results based the same or similar numerical models, e.g., OpenFOAM, the study highlights uncertainties in setting up a numerical model for complex wave structure interaction simulations such as those involving a FOWT and therefore the importance of proper code validation and verification studies.
{"title":"Modelling the hydrodynamic response of a floating offshore wind turbine – a comparative study","authors":"Shimin Yu , Edward Ransley , Ling Qian , Yang Zhou , Scott Brown , Deborah Greaves , Martyn Hann , Anna Holcombe , Emma Edwards , Tom Tosdevin , Sudhir Jagdale , Qian Li , Yi Zhang , Ningbo Zhang , Shiqiang Yan , Qingwei Ma , Bonaventura Tagliafierro , Salvatore Capasso , Iván Martínez-Estévez , Malin Göteman , Javier L. Lara","doi":"10.1016/j.apor.2025.104441","DOIUrl":"10.1016/j.apor.2025.104441","url":null,"abstract":"<div><div>This paper summarises the work conducted within the 1st FOWT (Floating Offshore Wind Turbine) Comparative Study organised by the EPSRC (UK) ‘Extreme loading on FOWTs under complex environmental conditions’ and ‘Collaborative computational project on wave structure interaction (CCP-WSI)’ projects. The hydrodynamic response of a FOWT support structure is simulated with a range of numerical models based on potential theory, Morison equation, Navier-Stokes solvers and hybrid methods coupling different flow solvers. A series of load cases including the static equilibrium tests, free decay tests, operational and extreme focused wave cases are considered for the UMaine VolturnUS-S semi-submersible platform, and the results from 17 contributions are analysed and compared with each other and against the experimental data from a 1:70 scale model test performed in the COAST Laboratory Ocean Basin at the University of Plymouth. It is shown that most numerical models can predict similar results for the heave response, but significant discrepancies exist in the prediction of the surge and pitch responses as well as the mooring line loads. For the extreme focused wave case, while both Navier–Stokes and potential flow base models tend to produce larger errors in terms of the root mean squared error than the operational focused wave case, the Navier-Stokes based models generally perform better. Given the fact that variations in the solutions (sometimes large) also present in the results based the same or similar numerical models, e.g., OpenFOAM, the study highlights uncertainties in setting up a numerical model for complex wave structure interaction simulations such as those involving a FOWT and therefore the importance of proper code validation and verification studies.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"155 ","pages":"Article 104441"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143174569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.apor.2025.104431
Hai Zhu , Jiawang Chen , Yuan Lin , Peng Zhou , Kaichuang Wang , Peiwen Lin , Xiaoqing Peng , Haonan Li , Jin Guo , Xueyu Ren , Han Ge , Zhonghui Zhou , Yuping Fang , Zhenjun Jiang , Feng Gao , Wendi Dai , Xuehua Chen , Guoming Cao , Honghe Li , Xu Gao , Yuanjie Chen
This study addresses the critical challenge of inspecting subsea pipelines in the highly turbid waters of the East China Sea, where visibility significantly hinders conventional methods. To overcome these limitations, we developed an advanced unmanned submarine light-scanning system that leverages structured light technology within a large-scale underwater dry cabin. This innovative setup enables high-precision, in-situ external inspections of pipelines by ensuring comprehensive scanning coverage even in poor visibility conditions. The core components of our system include the shipboard-controlled structured light scanning driving system (SLSDS) for precise motion control, enabling seamless full-pipeline coverage in a single deployment, and the shipboard electric control subsystem (SECS), which integrates power supply, sensing, communication, and control functionalities. Applied in the Zhoushan sea area, the dry-cabin scanning system demonstrated a 50–66.7 % reduction in inspection time and a tenfold improvement in data resolution over traditional technologies. These results highlight the system's effectiveness, efficiency, and safety advantages, offering a robust solution for pipeline inspections in offshore environments with compromised visibility. The system's capability to significantly enhance inspection accuracy and operational efficiency underscores its potential for broader application in similar high-turbidity settings.
{"title":"The application of structured light for external subsea pipeline inspection based on the underwater dry cabin","authors":"Hai Zhu , Jiawang Chen , Yuan Lin , Peng Zhou , Kaichuang Wang , Peiwen Lin , Xiaoqing Peng , Haonan Li , Jin Guo , Xueyu Ren , Han Ge , Zhonghui Zhou , Yuping Fang , Zhenjun Jiang , Feng Gao , Wendi Dai , Xuehua Chen , Guoming Cao , Honghe Li , Xu Gao , Yuanjie Chen","doi":"10.1016/j.apor.2025.104431","DOIUrl":"10.1016/j.apor.2025.104431","url":null,"abstract":"<div><div>This study addresses the critical challenge of inspecting subsea pipelines in the highly turbid waters of the East China Sea, where visibility significantly hinders conventional methods. To overcome these limitations, we developed an advanced unmanned submarine light-scanning system that leverages structured light technology within a large-scale underwater dry cabin. This innovative setup enables high-precision, in-situ external inspections of pipelines by ensuring comprehensive scanning coverage even in poor visibility conditions. The core components of our system include the shipboard-controlled structured light scanning driving system (SLSDS) for precise motion control, enabling seamless full-pipeline coverage in a single deployment, and the shipboard electric control subsystem (SECS), which integrates power supply, sensing, communication, and control functionalities. Applied in the Zhoushan sea area, the dry-cabin scanning system demonstrated a 50–66.7 % reduction in inspection time and a tenfold improvement in data resolution over traditional technologies. These results highlight the system's effectiveness, efficiency, and safety advantages, offering a robust solution for pipeline inspections in offshore environments with compromised visibility. The system's capability to significantly enhance inspection accuracy and operational efficiency underscores its potential for broader application in similar high-turbidity settings.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"155 ","pages":"Article 104431"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143176384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.apor.2025.104444
Chenfeng Huang, Yongsheng Dou, Zuojing Su, Xianku Zhang
This paper presents an adaptive prescribed-time control scheme to the dynamic positioning (DP) system of semi-submersible platforms (SSPs) in the presence of asymmetric input saturation. To eliminate the adverse effect induced by the input saturation, a saturated compensating auxiliary system is introduced. The system singularity problem is removed by automatically enlarging and recovering the velocity error by implanting a modification saturated signals into the velocity error. The dynamic errors are transformed into a new error variable by using a fixed-time tracking performance function (FTTPF). After that, the fixed-time funnel boundaries (FTFBs) will no longer need to be redesigned according to various initial attitude errors. Meanwhile, the trajectories of the attitude errors are limited to the designed boundaries over a finite time interval. In addition, the new errors in the closed-loop system are guaranteed to be semi-global uniformly ultimately bounded (SGUUB). Finally, two simulations are performed to illustrate the effectiveness and superiority of the proposed scheme.
{"title":"Neural prescribed-time dynamic positioning control of semi-submersible platforms with asymmetric input saturation","authors":"Chenfeng Huang, Yongsheng Dou, Zuojing Su, Xianku Zhang","doi":"10.1016/j.apor.2025.104444","DOIUrl":"10.1016/j.apor.2025.104444","url":null,"abstract":"<div><div>This paper presents an adaptive prescribed-time control scheme to the dynamic positioning (DP) system of semi-submersible platforms (SSPs) in the presence of asymmetric input saturation. To eliminate the adverse effect induced by the input saturation, a saturated compensating auxiliary system is introduced. The system singularity problem is removed by automatically enlarging and recovering the velocity error by implanting a modification saturated signals into the velocity error. The dynamic errors are transformed into a new error variable by using a fixed-time tracking performance function (FTTPF). After that, the fixed-time funnel boundaries (FTFBs) will no longer need to be redesigned according to various initial attitude errors. Meanwhile, the trajectories of the attitude errors are limited to the designed boundaries over a finite time interval. In addition, the new errors in the closed-loop system are guaranteed to be semi-global uniformly ultimately bounded (SGUUB). Finally, two simulations are performed to illustrate the effectiveness and superiority of the proposed scheme.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"155 ","pages":"Article 104444"},"PeriodicalIF":4.3,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143328412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.apor.2024.104404
Haobo Li , Hu Ding , Tienchong Chang , Liqun Chen
A traditional track nonlinear energy sink (TNES) is very sensitive to input energy. In order to extend effective energy threshold range of a TNES, a track tristable nonlinear energy sink (TTNES) with rotational inertia is proposed. Firstly, motion equations of a linear structure coupled with a TTNES are derived. The TTNES can translate into the track bistable NES (TBNES) and the track monostable NES (TMNES, traditional TNES) by adjusting track shape parameters. Secondly, equilibrium stability and bifurcation of a TTNES are determined. Then, analytical analysis and vibration reduction performance of a TTNES are conducted under impulsive excitations. In addition, approximate analysis and vibration reduction performance of a TTNES are carried out under harmonic excitations. Finally, a TTNES is applied to vibration mitigation of an offshore platform under sea wave excitations. The results show the TTNES exhibits better vibration reduction performance and higher robustness than traditional TNES when subjected to impulsive and harmonic excitations. In addition, the TTNES can effectively reduce the response of an offshore platform under sea wave excitations. This research provides the necessary theoretical basis for designing and applying the TTNES.
{"title":"Optimization and performance analysis of a track tristable nonlinear energy sink subjected to impulsive, harmonic and sea wave excitations","authors":"Haobo Li , Hu Ding , Tienchong Chang , Liqun Chen","doi":"10.1016/j.apor.2024.104404","DOIUrl":"10.1016/j.apor.2024.104404","url":null,"abstract":"<div><div>A traditional track nonlinear energy sink (TNES) is very sensitive to input energy. In order to extend effective energy threshold range of a TNES, a track tristable nonlinear energy sink (TTNES) with rotational inertia is proposed. Firstly, motion equations of a linear structure coupled with a TTNES are derived. The TTNES can translate into the track bistable NES (TBNES) and the track monostable NES (TMNES, traditional TNES) by adjusting track shape parameters. Secondly, equilibrium stability and bifurcation of a TTNES are determined. Then, analytical analysis and vibration reduction performance of a TTNES are conducted under impulsive excitations. In addition, approximate analysis and vibration reduction performance of a TTNES are carried out under harmonic excitations. Finally, a TTNES is applied to vibration mitigation of an offshore platform under sea wave excitations. The results show the TTNES exhibits better vibration reduction performance and higher robustness than traditional TNES when subjected to impulsive and harmonic excitations. In addition, the TTNES can effectively reduce the response of an offshore platform under sea wave excitations. This research provides the necessary theoretical basis for designing and applying the TTNES.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"154 ","pages":"Article 104404"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.apor.2025.104418
Zihao Zhao , Wanqing Wu , Heping Wang , Yu Zhou , Yueyang Sun , Maocheng Huang , Qinggong Zheng
Liquefaction is one of the main causes of catastrophic accidents during sea transport of liquefiable cargo. Complex rheological processes are often required when liquefying liquefiable cargo. In order to study the rheological properties of the liquefaction process, Cyclic Triaxial Test was used to study the liquefaction process of laterite nickel ore under different consolidation pressures and dynamic loads. The rheological properties during the liquefaction process were quantitatively analyzed based on the apparent viscosity ηap. Subsequently, the liquefaction process was quantitatively described using rheological characteristic parameters and phase transition points (Ns, Nl) were defined to divide different stages. The phase transition mechanism was combined with the shear stress-shear strain rate curve, and the effects of initial effective consolidation pressure σ′0, axial dynamic load σd, and number of cycles N on the rheological characteristics of laterite nickel ore were further analyzed. Finally, an explicit expression of ηap during liquefaction was obtained by an intelligent algorithm, which could be a data basis for subsequent risk research of liquefiable cargo during sea transport. This study provides a method for quantitative analysis of load and rheological properties of liquefiable cargo.
{"title":"Research on the influence of environmental loads on the rheological properties of laterite nickel ore during liquefaction","authors":"Zihao Zhao , Wanqing Wu , Heping Wang , Yu Zhou , Yueyang Sun , Maocheng Huang , Qinggong Zheng","doi":"10.1016/j.apor.2025.104418","DOIUrl":"10.1016/j.apor.2025.104418","url":null,"abstract":"<div><div>Liquefaction is one of the main causes of catastrophic accidents during sea transport of liquefiable cargo. Complex rheological processes are often required when liquefying liquefiable cargo. In order to study the rheological properties of the liquefaction process, Cyclic Triaxial Test was used to study the liquefaction process of laterite nickel ore under different consolidation pressures and dynamic loads. The rheological properties during the liquefaction process were quantitatively analyzed based on the apparent viscosity <em>η<sub>ap</sub></em>. Subsequently, the liquefaction process was quantitatively described using rheological characteristic parameters and phase transition points (<em>N<sub>s</sub>, N<sub>l</sub></em>) were defined to divide different stages. The phase transition mechanism was combined with the shear stress-shear strain rate curve, and the effects of initial effective consolidation pressure <em>σ′</em><sub>0</sub>, axial dynamic load <em>σ<sub>d,</sub></em> and number of cycles <em>N</em> on the rheological characteristics of laterite nickel ore were further analyzed. Finally, an explicit expression of <em>η<sub>ap</sub></em> during liquefaction was obtained by an intelligent algorithm, which could be a data basis for subsequent risk research of liquefiable cargo during sea transport. This study provides a method for quantitative analysis of load and rheological properties of liquefiable cargo.</div></div>","PeriodicalId":8261,"journal":{"name":"Applied Ocean Research","volume":"154 ","pages":"Article 104418"},"PeriodicalIF":4.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}