Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100674
Je-In Kim , Bu-Geun Paik , Jong-Woo Ahn , Il-Ryong Park
This study presents a comprehensive estimation of full-scale self-propulsion performance for a high-speed, twin-screw, single-skeg surface vessel using Reynolds-averaged Navier–Stokes (RANS)-based computational fluid dynamics (CFD). Resistance, propeller open-water characteristics, and self-propulsion behavior were analyzed by incorporating recent benchmark data on surface roughness—identified as a critical factor in full-scale CFD analysis. The numerical predictions, including key self-propulsion parameters, were validated against full-scale performance data extrapolated from model tests conducted at KRISO. Additionally, ship speeds were estimated by simulating surge motion induced by thrust from specified propeller RPMs under wave conditions, replicating sea trial environments. Finally, ship speeds corresponding to the prescribed RPMs were compared across CFD simulations, model tests, and actual sea trial results.
{"title":"RANS analysis of the self-propulsion performance for a twin-screw ship","authors":"Je-In Kim , Bu-Geun Paik , Jong-Woo Ahn , Il-Ryong Park","doi":"10.1016/j.ijnaoe.2025.100674","DOIUrl":"10.1016/j.ijnaoe.2025.100674","url":null,"abstract":"<div><div>This study presents a comprehensive estimation of full-scale self-propulsion performance for a high-speed, twin-screw, single-skeg surface vessel using Reynolds-averaged Navier–Stokes (RANS)-based computational fluid dynamics (CFD). Resistance, propeller open-water characteristics, and self-propulsion behavior were analyzed by incorporating recent benchmark data on surface roughness—identified as a critical factor in full-scale CFD analysis. The numerical predictions, including key self-propulsion parameters, were validated against full-scale performance data extrapolated from model tests conducted at KRISO. Additionally, ship speeds were estimated by simulating surge motion induced by thrust from specified propeller RPMs under wave conditions, replicating sea trial environments. Finally, ship speeds corresponding to the prescribed RPMs were compared across CFD simulations, model tests, and actual sea trial results.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100674"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144702178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100688
Xu Geng , Dong Qin
Ships navigating in complex sea conditions typically do not experience catastrophic failure due to a single extreme load; rather, the primary structural components such as stiffened panels of the hull undergo plastic deformation under repeated cyclic loading and may develop cracks under low-cycle fatigue. This leads to a decrease in ultimate bearing capacity and eventual structural failure due to insufficient ultimate strength, resulting in hull buckling. Currently, methods for evaluating the ultimate strength of ship hull stiffened panels under cyclic extreme loading considering the coupling effects of accumulative plasticity and low-cycle fatigue are not well-developed. Therefore, there is a need for research into computational methods for assessing the ultimate strength of stiffened panels structures considering the coupling effects of these two factors. This paper investigates the ultimate load-bearing capacity of pre-cracked stiffened panels under the combined effects of accumulative plasticity and low-cycle fatigue. During the experiments, hysteresis curves of stress-strain relationships and relevant fracture parameters for stiffened panels were obtained under various crack positions and load conditions. Ultimately, the study provides the ultimate load-bearing capacity of stiffened panels considering low-cycle fatigue and accumulative plasticity interactions, offering a foundational calculation basis for designing vessels under severe sea conditions.
{"title":"Experimental study on ultimate bearing capacity of pre-cracked ship hull stiffened panel under low-cycle fatigue and accumulative plasticity coupling","authors":"Xu Geng , Dong Qin","doi":"10.1016/j.ijnaoe.2025.100688","DOIUrl":"10.1016/j.ijnaoe.2025.100688","url":null,"abstract":"<div><div>Ships navigating in complex sea conditions typically do not experience catastrophic failure due to a single extreme load; rather, the primary structural components such as stiffened panels of the hull undergo plastic deformation under repeated cyclic loading and may develop cracks under low-cycle fatigue. This leads to a decrease in ultimate bearing capacity and eventual structural failure due to insufficient ultimate strength, resulting in hull buckling. Currently, methods for evaluating the ultimate strength of ship hull stiffened panels under cyclic extreme loading considering the coupling effects of accumulative plasticity and low-cycle fatigue are not well-developed. Therefore, there is a need for research into computational methods for assessing the ultimate strength of stiffened panels structures considering the coupling effects of these two factors. This paper investigates the ultimate load-bearing capacity of pre-cracked stiffened panels under the combined effects of accumulative plasticity and low-cycle fatigue. During the experiments, hysteresis curves of stress-strain relationships and relevant fracture parameters for stiffened panels were obtained under various crack positions and load conditions. Ultimately, the study provides the ultimate load-bearing capacity of stiffened panels considering low-cycle fatigue and accumulative plasticity interactions, offering a foundational calculation basis for designing vessels under severe sea conditions.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100688"},"PeriodicalIF":3.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100664
Martin Alexandersson , Wengang Mao , Jonas W. Ringsberg , Martin Kjellberg
Ships with wind-assisted propulsion systems (WAPS) are often equipped with large rudders to compensate for WAPS-induced drifting forces. The WAPS also significantly affects the effectiveness of mathematical models used to describe the ship’s maneuvering characteristics. In this study, a modular maneuvering model is proposed to enhance the original MMG model, with the aim of producing accurate maneuvering simulations for ships with WAPS. Methods of virtual captive tests (VCT) are proposed to recreate the forces acting on WAPS ships during free-running model tests (FRMT) in motor mode, identifying all the parameters in the modular model. The hydrodynamic damping coefficients within the model are determined through linear regression of the VCT data. The added masses are then determined from pure yaw and pure sway simulations using a fully nonlinear potential flow (FNPF) panel method. Two ships designed for WAPS, wPCC and Optiwise, are used to validate the proposed method based on the inverse dynamics of their experimental model tests. The wPCC is equipped with a semi-empirical rudder that has previously shown to work well for this twin-rudder ship. The Optiwise single rudder is modeled with a new quadratic version of the MMG rudder model, proposed in this paper. Inverse dynamics analysis, together with state VCTs, is concluded to be an efficient way to analyze the models, and the maneuvering model can be efficiently identified when the correct VCTs are used in the proposed method. However, the inverse dynamics analysis also revealed potential errors in the wPCC VCT data due to false assumptions about wave generation and roll motion. The Optiwise test case, where these assumptions should be more valid, showed much better agreement with the FRMT inverse dynamics.
{"title":"Identification of maneuvering models for wind-assisted ships with large rudders using virtual captive tests","authors":"Martin Alexandersson , Wengang Mao , Jonas W. Ringsberg , Martin Kjellberg","doi":"10.1016/j.ijnaoe.2025.100664","DOIUrl":"10.1016/j.ijnaoe.2025.100664","url":null,"abstract":"<div><div>Ships with wind-assisted propulsion systems (WAPS) are often equipped with large rudders to compensate for WAPS-induced drifting forces. The WAPS also significantly affects the effectiveness of mathematical models used to describe the ship’s maneuvering characteristics. In this study, a modular maneuvering model is proposed to enhance the original MMG model, with the aim of producing accurate maneuvering simulations for ships with WAPS. Methods of virtual captive tests (VCT) are proposed to recreate the forces acting on WAPS ships during free-running model tests (FRMT) in motor mode, identifying all the parameters in the modular model. The hydrodynamic damping coefficients within the model are determined through linear regression of the VCT data. The added masses are then determined from pure yaw and pure sway simulations using a fully nonlinear potential flow (FNPF) panel method. Two ships designed for WAPS, wPCC and Optiwise, are used to validate the proposed method based on the inverse dynamics of their experimental model tests. The wPCC is equipped with a semi-empirical rudder that has previously shown to work well for this twin-rudder ship. The Optiwise single rudder is modeled with a new quadratic version of the MMG rudder model, proposed in this paper. Inverse dynamics analysis, together with state VCTs, is concluded to be an efficient way to analyze the models, and the maneuvering model can be efficiently identified when the correct VCTs are used in the proposed method. However, the inverse dynamics analysis also revealed potential errors in the wPCC VCT data due to false assumptions about wave generation and roll motion. The Optiwise test case, where these assumptions should be more valid, showed much better agreement with the FRMT inverse dynamics.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100664"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100652
Chang Sub Song , Jong-Ho Nam
Currently, the shipbuilding industry is experiencing a surge in orders due to the rising demand for eco-friendly ships, necessitating the optimal use of available resources for production. However, the production workforce has not fully recovered to the level required to meet these increased orders following large-scale industry restructuring. In particular, there is a shortage of highly skilled welders, and concerns are growing about the transfer of expertise due to an aging workforce and a lack of younger workers. Shipbuilders worldwide face similar challenges and are exploring various methods to transfer the tacit knowledge of skilled welders to less experienced workers, which has introduced unforeseen challenges. In this study, we develop a machine learning algorithm that suggests the optimal values of key welding variables for an AR-based welding training system designed to assist less skilled workers. We collected welding data from highly skilled workers using the FCAW (Flux-Cored Arc Welding) technique, which is commonly employed in the shipbuilding process. The welding variables that represent tacit knowledge were identified and trained using the Extra Trees Regressor model. Subsequently, a welding AR training system was implemented, allowing the trained model to guide users on the optimal values for welding variables. Finally, the effectiveness of this system in training welders was verified at a shipyard technical training center.
{"title":"Machine learning-based optimal value calculation for welding variables in AR training","authors":"Chang Sub Song , Jong-Ho Nam","doi":"10.1016/j.ijnaoe.2025.100652","DOIUrl":"10.1016/j.ijnaoe.2025.100652","url":null,"abstract":"<div><div>Currently, the shipbuilding industry is experiencing a surge in orders due to the rising demand for eco-friendly ships, necessitating the optimal use of available resources for production. However, the production workforce has not fully recovered to the level required to meet these increased orders following large-scale industry restructuring. In particular, there is a shortage of highly skilled welders, and concerns are growing about the transfer of expertise due to an aging workforce and a lack of younger workers. Shipbuilders worldwide face similar challenges and are exploring various methods to transfer the tacit knowledge of skilled welders to less experienced workers, which has introduced unforeseen challenges. In this study, we develop a machine learning algorithm that suggests the optimal values of key welding variables for an AR-based welding training system designed to assist less skilled workers. We collected welding data from highly skilled workers using the FCAW (Flux-Cored Arc Welding) technique, which is commonly employed in the shipbuilding process. The welding variables that represent tacit knowledge were identified and trained using the Extra Trees Regressor model. Subsequently, a welding AR training system was implemented, allowing the trained model to guide users on the optimal values for welding variables. Finally, the effectiveness of this system in training welders was verified at a shipyard technical training center.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100652"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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.ijnaoe.2025.100666
Donghyun Park , Jae-Yoon Jung , Beom Jin Park
This paper proposes a novel method for estimating ship operational performance degradation (SOPD) using a fuel oil consumption (FOC) prediction model based on deep neural networks with shortcut connections. The model leverages operational and environmental data from a crude oil tanker over a 21-month period to predict FOC and assess SOPD. A cumulative anchoring effect is introduced as a new feature of the FOC prediction model, capturing the impact of biofouling caused by prolonged anchoring in warm waters. In this study, SOPD is considered the additional fuel rate required for a journey leg due to degradation, which is estimated by comparing predicted FOC with and without the cumulative anchoring effect. The SOPD estimation is illustrated according to increasing journey legs based on the FOC prediction models. The proposed SOPD estimation method provides valuable insights for shipping companies to optimize operational schedules and improve fuel efficiency.
{"title":"Estimation of ship operational performance degradation using deep-learning-based fuel oil consumption prediction models","authors":"Donghyun Park , Jae-Yoon Jung , Beom Jin Park","doi":"10.1016/j.ijnaoe.2025.100666","DOIUrl":"10.1016/j.ijnaoe.2025.100666","url":null,"abstract":"<div><div>This paper proposes a novel method for estimating ship operational performance degradation (SOPD) using a fuel oil consumption (FOC) prediction model based on deep neural networks with shortcut connections. The model leverages operational and environmental data from a crude oil tanker over a 21-month period to predict FOC and assess SOPD. A cumulative anchoring effect is introduced as a new feature of the FOC prediction model, capturing the impact of biofouling caused by prolonged anchoring in warm waters. In this study, SOPD is considered the additional fuel rate required for a journey leg due to degradation, which is estimated by comparing predicted FOC with and without the cumulative anchoring effect. The SOPD estimation is illustrated according to increasing journey legs based on the FOC prediction models. The proposed SOPD estimation method provides valuable insights for shipping companies to optimize operational schedules and improve fuel efficiency.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100666"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144253536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100693
Mafira Ayu Ramdhani, Senthil Kumar Natarajan, Il Hyoung Cho
The Savonius hydrokinetic turbine (SHT), a vertical-axis turbine, efficiently extracts energy from low-speed water currents in rivers, canals, and marine environments. Optimizing the tip speed ratio (TSR), gap ratio (GR), and immersion ratio () enhances its power extraction efficiency. Traditionally, optimization relies on computationally intensive CFD simulations, which are time-consuming. To address this, a machine learning-based approach, specifically an Artificial Neural Network (ANN) model is employed, reducing reliance on extensive CFD simulations while maintaining accuracy. The ANN model was trained using CFD simulations performed in StarCCM+ and then used to predict power coefficients for various design configurations. The CFD simulations are validated against experimental results reported in the literature. The optimal parameters, tip speed ratio (0.7808), gap ratio (−0.0498), and immersion ratio (1.0661) yielded the highest power coefficient (0.2179). This study demonstrates that machine learning accurately predicts turbine performance, reducing reliance on extensive CFD simulations, making turbine optimization more efficient.
{"title":"Design optimization of Savonius hydrokinetic turbine with aid of an artificial neural network model","authors":"Mafira Ayu Ramdhani, Senthil Kumar Natarajan, Il Hyoung Cho","doi":"10.1016/j.ijnaoe.2025.100693","DOIUrl":"10.1016/j.ijnaoe.2025.100693","url":null,"abstract":"<div><div>The Savonius hydrokinetic turbine (SHT), a vertical-axis turbine, efficiently extracts energy from low-speed water currents in rivers, canals, and marine environments. Optimizing the tip speed ratio (TSR), gap ratio (GR), and immersion ratio (<span><math><mrow><mi>Z</mi><mo>/</mo><mi>D</mi></mrow></math></span>) enhances its power extraction efficiency. Traditionally, optimization relies on computationally intensive CFD simulations, which are time-consuming. To address this, a machine learning-based approach, specifically an Artificial Neural Network (ANN) model is employed, reducing reliance on extensive CFD simulations while maintaining accuracy. The ANN model was trained using CFD simulations performed in StarCCM+ and then used to predict power coefficients for various design configurations. The CFD simulations are validated against experimental results reported in the literature. The optimal parameters, tip speed ratio (0.7808), gap ratio (−0.0498), and immersion ratio (1.0661) yielded the highest power coefficient (0.2179). This study demonstrates that machine learning accurately predicts turbine performance, reducing reliance on extensive CFD simulations, making turbine optimization more efficient.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100693"},"PeriodicalIF":3.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145358280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100694
Bingyao Tan , Yulong Tuo , Yuanhui Wang , Zhouhua Peng , Shasha Wang
This paper proposes an adaptive event-triggered anti-windup dynamic positioning (DP) control method for a turret-moored vessel subject to the uncertainties and nonconvex control input constraint. Firstly, by introducing a nonconvex constraint operator, the designed control input is mapped to the actual control input vector with the maximum amplitude constraint in the same direction, thereby ensuring that the actual control input remains within the nonconvex constraint set. Secondly, the uncertainties are ingeniously separated into an unavailable single parameter and available state-related items. The unavailable single parameter is estimated by an adaptive law online. Then, an adaptive nonconvex constraint anti-windup DP controller is proposed based on the single parameter adaptive law and the nonconvex constraint operator. Furthermore, we integrate an adaptive event-triggered mechanism into the DP controller to decrease its execution frequency. The adaptive event-triggered mechanism can effectively balance the control performance and control signal update frequency. Finally, the effectiveness of the proposed methods is validated through simulations.
{"title":"Adaptive event-triggered anti-windup control for dynamic positioning of turret-moored vessels with nonconvex input constraint and uncertainties","authors":"Bingyao Tan , Yulong Tuo , Yuanhui Wang , Zhouhua Peng , Shasha Wang","doi":"10.1016/j.ijnaoe.2025.100694","DOIUrl":"10.1016/j.ijnaoe.2025.100694","url":null,"abstract":"<div><div>This paper proposes an adaptive event-triggered anti-windup dynamic positioning (DP) control method for a turret-moored vessel subject to the uncertainties and nonconvex control input constraint. Firstly, by introducing a nonconvex constraint operator, the designed control input is mapped to the actual control input vector with the maximum amplitude constraint in the same direction, thereby ensuring that the actual control input remains within the nonconvex constraint set. Secondly, the uncertainties are ingeniously separated into an unavailable single parameter and available state-related items. The unavailable single parameter is estimated by an adaptive law online. Then, an adaptive nonconvex constraint anti-windup DP controller is proposed based on the single parameter adaptive law and the nonconvex constraint operator. Furthermore, we integrate an adaptive event-triggered mechanism into the DP controller to decrease its execution frequency. The adaptive event-triggered mechanism can effectively balance the control performance and control signal update frequency. Finally, the effectiveness of the proposed methods is validated through simulations.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100694"},"PeriodicalIF":3.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145463087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100653
SeongMo Yeon, Chang Seop Kwon, Yoo-Chul Kim, Kwang Soo Kim, Yeon Gyu Kim, Yun Ho Kim, Hee Jin Kang
The study investigated a Flettner rotor performance on a hull, analyzing design modifications and wind profiles for a small catamaran which designed by KRISO for the K-Energy Observer platform was analyzed. The rotor mounted on the hull showed a nearly 48% performance degradation in lift coefficient compared to the standalone rotor due to the disturbed flow by the hull at spin ratios 3–4. Two design factors were examined to improve performance: foundation shape and bottom configuration of the rotor. A square foundation shape showed relatively better improvement but it was not significant. On the other hand, it was found that the rotating end plate significantly improved thrust, achieving up to 80% of the standalone rotor’s performance. Comparing uniform and Norwegian Petroleum Directorate (NPD) wind profiles, the NPD profile showed a 12% improvement due to stronger winds at the rotor’s upper section. The study also compared performance under different wind directions and it showed a 20% increase at 30° and 18% at 60° for the original configuration. In contrast, the rotating end plate configuration showed a 6% decrease at 30° but a 10% increase at 60°. However, overall performance improvement was observed in the rotating end plate configuration with increases of 12%, 34%, and 44% for 30°, 60° and 90° compared to the original configuration. Additionally, under a 5° inclined hull condition, performance decreased by 21% for the original configuration but only 13% for the rotating end plate configuration, which highlighted the design’s effectiveness in mitigating performance loss.
{"title":"Performance analysis of Flettner rotor considering Marine wind profile and ship installation using CFD","authors":"SeongMo Yeon, Chang Seop Kwon, Yoo-Chul Kim, Kwang Soo Kim, Yeon Gyu Kim, Yun Ho Kim, Hee Jin Kang","doi":"10.1016/j.ijnaoe.2025.100653","DOIUrl":"10.1016/j.ijnaoe.2025.100653","url":null,"abstract":"<div><div>The study investigated a Flettner rotor performance on a hull, analyzing design modifications and wind profiles for a small catamaran which designed by KRISO for the K-Energy Observer platform was analyzed. The rotor mounted on the hull showed a nearly 48% performance degradation in lift coefficient compared to the standalone rotor due to the disturbed flow by the hull at spin ratios 3–4. Two design factors were examined to improve performance: foundation shape and bottom configuration of the rotor. A square foundation shape showed relatively better improvement but it was not significant. On the other hand, it was found that the rotating end plate significantly improved thrust, achieving up to 80% of the standalone rotor’s performance. Comparing uniform and Norwegian Petroleum Directorate (NPD) wind profiles, the NPD profile showed a 12% improvement due to stronger winds at the rotor’s upper section. The study also compared performance under different wind directions and it showed a 20% increase at 30° and 18% at 60° for the original configuration. In contrast, the rotating end plate configuration showed a 6% decrease at 30° but a 10% increase at 60°. However, overall performance improvement was observed in the rotating end plate configuration with increases of 12%, 34%, and 44% for 30°, 60° and 90° compared to the original configuration. Additionally, under a 5° inclined hull condition, performance decreased by 21% for the original configuration but only 13% for the rotating end plate configuration, which highlighted the design’s effectiveness in mitigating performance loss.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100653"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143735142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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.ijnaoe.2025.100687
Yijie Zhao , Zhenju Chuang , Yan Qu , Haoyang Yin , Zhenze Yang , Lulin Xia
The rapid development of offshore wind power in cold regions drives turbine deployment into deep-sea areas, yet ice-induced loads pose severe challenges to structural safety. This study aims to accurately predict dynamic responses of offshore wind turbines under ice-wind coupling, proposing a Discrete Element Method-Wind Turbine Integrated Analysis (DEM-WTIA) approach. This method synchronously simulates ice fragmentation processes and aero-structural dynamic responses by constructing an integrated model with rotor and control systems. Findings reveal: The model precisely captures transient energy dissipation during ice crushing and characterizes high-low frequency coupling effects with nonlinear superposition of ice-wind-wave loads; Tower-top displacement sensitivity to ice loads significantly exceeds foundation displacement; Under no-wind/cut-in wind speeds (3–5 m/s), ice dominates tower vibration, while aerodynamic damping suppresses ice-induced vibrations at rated/cut-out speeds; Spectral analysis shows dominant displacement frequency shifts from 0.27 Hz (near OWT fundamental frequency) to 0.24 Hz as wind increases; Sensitivity analysis indicates ice thickness sensitivity index (35.6) far exceeds ice velocity (7.2) in parked mode; Anti-ice design identifies 70° cone angle as optimal for monopile foundations. This research provides critical theoretical support and a novel simulation method for anti-ice design of offshore wind structures in cold seas, offering key technical guidance for far-sea wind farm planning.
{"title":"Integrated analysis of ice-induced vibration characteristics of monopile offshore wind turbines","authors":"Yijie Zhao , Zhenju Chuang , Yan Qu , Haoyang Yin , Zhenze Yang , Lulin Xia","doi":"10.1016/j.ijnaoe.2025.100687","DOIUrl":"10.1016/j.ijnaoe.2025.100687","url":null,"abstract":"<div><div>The rapid development of offshore wind power in cold regions drives turbine deployment into deep-sea areas, yet ice-induced loads pose severe challenges to structural safety. This study aims to accurately predict dynamic responses of offshore wind turbines under ice-wind coupling, proposing a Discrete Element Method-Wind Turbine Integrated Analysis (DEM-WTIA) approach. This method synchronously simulates ice fragmentation processes and aero-structural dynamic responses by constructing an integrated model with rotor and control systems. Findings reveal: The model precisely captures transient energy dissipation during ice crushing and characterizes high-low frequency coupling effects with nonlinear superposition of ice-wind-wave loads; Tower-top displacement sensitivity to ice loads significantly exceeds foundation displacement; Under no-wind/cut-in wind speeds (3–5 m/s), ice dominates tower vibration, while aerodynamic damping suppresses ice-induced vibrations at rated/cut-out speeds; Spectral analysis shows dominant displacement frequency shifts from 0.27 Hz (near OWT fundamental frequency) to 0.24 Hz as wind increases; Sensitivity analysis indicates ice thickness sensitivity index (35.6) far exceeds ice velocity (7.2) in parked mode; Anti-ice design identifies 70° cone angle as optimal for monopile foundations. This research provides critical theoretical support and a novel simulation method for anti-ice design of offshore wind structures in cold seas, offering key technical guidance for far-sea wind farm planning.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100687"},"PeriodicalIF":3.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-01DOI: 10.1016/j.ijnaoe.2025.100661
Jingjing Wu, Qichang He
The layout of pipeline supports (LPS) is essential for ensuring the safety of pipeline, which prioritize safety while considering spatial arrangement, pipeline characteristics, and technical constraints. Due to the complexity of the design process, there has been a long-term reliance on manual design, resulting in significant efficiency bottlenecks in the design phase. The research introduces a design framework for LPS based on sequential generation. Initially, a feature vector is defined by focusing on the significant design factors. Subsequently, a knowledge-driven variable-step-size sampling method introduces to optimize efficiency without compromising effectiveness. Then, the sampling sequence is processed through a Multi-Heads-Attention based Encoder (MHA-Encoder) to predict labels for each point in the sequence, which indicating the support type and its index signifying the placement. Finally, the proposed method’s validity was confirmed via real-world design cases, demonstrating an accuracy of 91.55% with minimal errors and a 40-fold reduction in the design cycle.
管道支架的布置是保证管道安全的关键，在考虑管道空间布置、管道特性和技术约束的前提下，将安全放在首位。由于设计过程的复杂性，长期依赖人工设计，导致设计阶段的效率瓶颈显著。介绍了一种基于顺序生成的LPS设计框架。最初，特征向量是通过关注重要的设计因素来定义的。随后，引入知识驱动的变步长采样方法，在不影响效率的前提下优化效率。然后，通过基于多头注意的编码器（Multi-Heads-Attention - based Encoder, MHA-Encoder）对采样序列进行处理，预测序列中每个点的标签，这些标签表示支持类型，其索引表示放置位置。最后，通过实际设计案例验证了该方法的有效性，其精度为91.55%，误差最小，设计周期缩短了40倍。
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