Pub Date : 2025-12-03DOI: 10.1016/j.ijnaoe.2025.100711
Fan Zhang , Qikai Zhang , Dong Peng , Yudi Wang , Yihe Wang , Qi Qin , Shihong Hu , Gang Wu
Recent field observations from the Xuelong icebreaker indicate that line contact induced bending failures of ice sheets are prevalent during consecutive ice breaking processes. However, the corresponding ice force and breaking length have rarely been studied. Against this backdrop, this study proposes a model with seven independent input parameters to characterize the loading scenario without assuming ice sheet geometric symmetry. The normalized governing equation based on the theory of thin plates on elastic foundations is solved by the finite element (FE) method, and the results are further utilized to train a XGBoost model. The established line contact induced bending failure model is implemented into a non-smooth discrete element method (DEM) framework for ship-ice interaction simulations, and the numerical result for ice resistance of the Xuelong 2 icebreaker in level ice is validated against model test data. This study facilitates a more accurate real-time description of ice-sloping structure interactions.
{"title":"Line contact induced bending failures of ice sheets during ship-ice interactions","authors":"Fan Zhang , Qikai Zhang , Dong Peng , Yudi Wang , Yihe Wang , Qi Qin , Shihong Hu , Gang Wu","doi":"10.1016/j.ijnaoe.2025.100711","DOIUrl":"10.1016/j.ijnaoe.2025.100711","url":null,"abstract":"<div><div>Recent field observations from the Xuelong icebreaker indicate that line contact induced bending failures of ice sheets are prevalent during consecutive ice breaking processes. However, the corresponding ice force and breaking length have rarely been studied. Against this backdrop, this study proposes a model with seven independent input parameters to characterize the loading scenario without assuming ice sheet geometric symmetry. The normalized governing equation based on the theory of thin plates on elastic foundations is solved by the finite element (FE) method, and the results are further utilized to train a XGBoost model. The established line contact induced bending failure model is implemented into a non-smooth discrete element method (DEM) framework for ship-ice interaction simulations, and the numerical result for ice resistance of the Xuelong 2 icebreaker in level ice is validated against model test data. This study facilitates a more accurate real-time description of ice-sloping structure interactions.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100711"},"PeriodicalIF":3.9,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789132","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}
Accurate determination of shear and pressure force distributions around a ship's hull is paramount for hydrodynamic optimization tasks, as integrating these fields across the hull's surface provides the total drag force applied on the hull. While Computational Fluid Dynamics (CFD) provides this capability, it is often limited by high computational cost and time-consuming pre-processing, post-processing, and simulation times. The challenge is further amplified during design exploration studies, where simulations are performed across multiple operational conditions. To address these limitations, we propose a soft-constrained Multitask deep neural network, named HydroForceNet, which serves as a surrogate model for CFD simulations on marine vessel hulls. Our proposed architecture can accurately predict pressure and shear distributions on various Wigley-based geometries and calculates the resistance components, using three-dimensional geometric and operational inputs, at a fraction of the computational cost of a traditional CFD evaluation. Finally, to further illustrate its applicability, the proposed artificial neural network is integrated into a genetic algorithm-based optimization task, producing a new hull geometry with a 15.77 % reduction of hydrodynamic resistance compared to a reference hull geometry, after evaluating over 2500 designs within 2 min, while faithfully reproducing the flow field.
{"title":"Predicting ship hull flow-field distributions using a soft-constrained ANN model","authors":"Christoforos Lefkiou , Phoevos (Foivos) Koukouvinis , Sotirios Chatzis , Stefanos Xyfolis","doi":"10.1016/j.ijnaoe.2025.100712","DOIUrl":"10.1016/j.ijnaoe.2025.100712","url":null,"abstract":"<div><div>Accurate determination of shear and pressure force distributions around a ship's hull is paramount for hydrodynamic optimization tasks, as integrating these fields across the hull's surface provides the total drag force applied on the hull. While Computational Fluid Dynamics (CFD) provides this capability, it is often limited by high computational cost and time-consuming pre-processing, post-processing, and simulation times. The challenge is further amplified during design exploration studies, where simulations are performed across multiple operational conditions. To address these limitations, we propose a soft-constrained Multitask deep neural network, named HydroForceNet, which serves as a surrogate model for CFD simulations on marine vessel hulls. Our proposed architecture can accurately predict pressure and shear distributions on various Wigley-based geometries and calculates the resistance components, using three-dimensional geometric and operational inputs, at a fraction of the computational cost of a traditional CFD evaluation. Finally, to further illustrate its applicability, the proposed artificial neural network is integrated into a genetic algorithm-based optimization task, producing a new hull geometry with a 15.77 % reduction of hydrodynamic resistance compared to a reference hull geometry, after evaluating over 2500 designs within 2 min, while faithfully reproducing the flow field.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100712"},"PeriodicalIF":3.9,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145788875","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 : 2025-12-02DOI: 10.1016/j.ijnaoe.2025.100713
Hyun Soo Kim , Myung-Il Roh
The utilization of natural gas is expanding as part of efforts to reduce greenhouse gas (GHG) emissions. Natural gas is typically liquefied at cryogenic temperatures in order to enhance the efficiency of maritime transport. When these cryogenic cargoes are shipped, BOG (Boil-Off Gas) is generated by the external heat and wave-induced ship motion. Proper management of BOG is critical to maintaining the cargo tank pressure within a safe operational range. In the case of LNG (Liquefied Natural Gas) carriers, BOG is used as fuel for main engines and generator engines, with any surplus being burned in the GCU (Gas Combustion Unit) or reliquefied by a reliquefaction system. Accurate prediction of BOG generation and cargo tank pressure is therefore essential for optimizing reliquefaction system operations and voyage planning. Although various experimental and CFD-based studies have been conducted, it remains challenging to capture the complex, irregular characteristics of real marine environments, particularly the effects of ship motion and sloshing. This study presents a framework for developing a data-driven model that predicts cargo tank pressure in LNG carriers. The data-driven model is based on long-term operation data from a 174K-class LNG carrier, enabling consideration of the combined effects of BOG consumption, reliquefaction performance, and marine environmental conditions on cargo tank pressure. The variables related to cargo tank pressure are derived from ship operation, BOG consumption, and marine environmental conditions. Several regression and machine learning algorithms were compared to identify the most effective predictive model. The model's accuracy was verified by comparing predicted values with actual measurements from an LNG carrier that had been in operation for 2 years, and the results confirmed high predictive accuracy. This approach provides a practical framework for data-driven cargo tank pressure prediction and contributes to improving energy efficiency and reducing GHG emissions in LNG carrier operations.
{"title":"Data-driven model for predicting cargo tank pressure of an LNG carrier considering environmental effects","authors":"Hyun Soo Kim , Myung-Il Roh","doi":"10.1016/j.ijnaoe.2025.100713","DOIUrl":"10.1016/j.ijnaoe.2025.100713","url":null,"abstract":"<div><div>The utilization of natural gas is expanding as part of efforts to reduce greenhouse gas (GHG) emissions. Natural gas is typically liquefied at cryogenic temperatures in order to enhance the efficiency of maritime transport. When these cryogenic cargoes are shipped, BOG (Boil-Off Gas) is generated by the external heat and wave-induced ship motion. Proper management of BOG is critical to maintaining the cargo tank pressure within a safe operational range. In the case of LNG (Liquefied Natural Gas) carriers, BOG is used as fuel for main engines and generator engines, with any surplus being burned in the GCU (Gas Combustion Unit) or reliquefied by a reliquefaction system. Accurate prediction of BOG generation and cargo tank pressure is therefore essential for optimizing reliquefaction system operations and voyage planning. Although various experimental and CFD-based studies have been conducted, it remains challenging to capture the complex, irregular characteristics of real marine environments, particularly the effects of ship motion and sloshing. This study presents a framework for developing a data-driven model that predicts cargo tank pressure in LNG carriers. The data-driven model is based on long-term operation data from a 174K-class LNG carrier, enabling consideration of the combined effects of BOG consumption, reliquefaction performance, and marine environmental conditions on cargo tank pressure. The variables related to cargo tank pressure are derived from ship operation, BOG consumption, and marine environmental conditions. Several regression and machine learning algorithms were compared to identify the most effective predictive model. The model's accuracy was verified by comparing predicted values with actual measurements from an LNG carrier that had been in operation for 2 years, and the results confirmed high predictive accuracy. This approach provides a practical framework for data-driven cargo tank pressure prediction and contributes to improving energy efficiency and reducing GHG emissions in LNG carrier operations.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"18 ","pages":"Article 100713"},"PeriodicalIF":3.9,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145735924","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.2025.100658
Chongfei Sun , Huaiyu Teng , Xiaoyan Ma , Hailong Chen , Liming Sun , Cun Shao , Fei Cao , Hengxu Liu
The increasing global demand for marine resource exploration, maritime rights protection, and deep-sea engineering applications highlights the need for the diversification of marine engineering equipment and the expansion of its deep-sea capabilities, presenting significant technical and economic value. As the use of small-scale marine engineering equipment in deep-sea environments becomes more prevalent, optimizing energy supply methods for such equipment is critical to ensure their durability and efficiency in complex marine conditions. This paper proposes an Inertial Tilting Electromagnetic-Triboelectric Hybrid Energy Converter (ITHEC), which efficiently harvests energy from ocean waves to power small marine engineering devices. A comprehensive design and optimization framework was developed for this energy converter. This framework was based on theoretical analysis and simulations of structural dynamics and characteristics. Validation experiments were conducted using a custom-built structural characteristics testing platform. The results showed that under horizontal harmonic motion excitation with an amplitude of d = 60 mm and a frequency of f = 1.5Hz, the open-circuit voltages of the triboelectric nanogenerator (TENG) and electromagnetic generator (EMG) reached 60V and 0.23V, respectively, with short-circuit currents of 1.3 μA and 2.2 mA, and peak power densities of 1.18 mW/m2 and 0.51 mW/m2. When arrayed, the hybrid energy converter can meet the operating current requirements of small marine sensors. This study offers an innovative solution for energy supply challenges in small marine equipment and establishes the practical viability of hybrid power systems for marine energy harvesting.
{"title":"Numerical and experimental investigation of an Inertial Tilting hybrid wave energy converter for powering small-scale marine systems","authors":"Chongfei Sun , Huaiyu Teng , Xiaoyan Ma , Hailong Chen , Liming Sun , Cun Shao , Fei Cao , Hengxu Liu","doi":"10.1016/j.ijnaoe.2025.100658","DOIUrl":"10.1016/j.ijnaoe.2025.100658","url":null,"abstract":"<div><div>The increasing global demand for marine resource exploration, maritime rights protection, and deep-sea engineering applications highlights the need for the diversification of marine engineering equipment and the expansion of its deep-sea capabilities, presenting significant technical and economic value. As the use of small-scale marine engineering equipment in deep-sea environments becomes more prevalent, optimizing energy supply methods for such equipment is critical to ensure their durability and efficiency in complex marine conditions. This paper proposes an Inertial Tilting Electromagnetic-Triboelectric Hybrid Energy Converter (ITHEC), which efficiently harvests energy from ocean waves to power small marine engineering devices. A comprehensive design and optimization framework was developed for this energy converter. This framework was based on theoretical analysis and simulations of structural dynamics and characteristics. Validation experiments were conducted using a custom-built structural characteristics testing platform. The results showed that under horizontal harmonic motion excitation with an amplitude of d = 60 mm and a frequency of <em>f</em> = 1.5Hz, the open-circuit voltages of the triboelectric nanogenerator (TENG) and electromagnetic generator (EMG) reached 60V and 0.23V, respectively, with short-circuit currents of 1.3 μA and 2.2 mA, and peak power densities of 1.18 mW/m<sup>2</sup> and 0.51 mW/m<sup>2</sup>. When arrayed, the hybrid energy converter can meet the operating current requirements of small marine sensors. This study offers an innovative solution for energy supply challenges in small marine equipment and establishes the practical viability of hybrid power systems for marine energy harvesting.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100658"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916875","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.2025.100656
JianYu Xiao , Zhuang Kang , Jing Leng , Ming Chen , Jun Liu
The deep seabed harbors abundant mineral resources. To achieve the economic viability of deep-sea mining, the efficiency of polymetallic nodule lifting is critical. In this study, we investigate the performance of air-lifting systems, which is a key component of deep-sea mining operations. Through two-phase flow simulations, we establish the relationship between the air-injection velocity and water-lifting velocity and validate the experimental data. We constructed a large-scale air-lifting system in a 20-m-deep water tank to explore the feasibility and energy efficiency of lifting water and nodules under varying air-injection velocities and depths. In detailed energy efficiency calculations, we determined the optimal operational parameters which provide novel insights into the design and optimization of deep-sea mining lifting systems. The experimental data and findings offer valuable references for future system designs that can enhance operational stability and economic feasibility.
{"title":"Numerical simulations and large-scale experimental research into air-lifting system for deep-sea mining","authors":"JianYu Xiao , Zhuang Kang , Jing Leng , Ming Chen , Jun Liu","doi":"10.1016/j.ijnaoe.2025.100656","DOIUrl":"10.1016/j.ijnaoe.2025.100656","url":null,"abstract":"<div><div>The deep seabed harbors abundant mineral resources. To achieve the economic viability of deep-sea mining, the efficiency of polymetallic nodule lifting is critical. In this study, we investigate the performance of air-lifting systems, which is a key component of deep-sea mining operations. Through two-phase flow simulations, we establish the relationship between the air-injection velocity and water-lifting velocity and validate the experimental data. We constructed a large-scale air-lifting system in a 20-m-deep water tank to explore the feasibility and energy efficiency of lifting water and nodules under varying air-injection velocities and depths. In detailed energy efficiency calculations, we determined the optimal operational parameters which provide novel insights into the design and optimization of deep-sea mining lifting systems. The experimental data and findings offer valuable references for future system designs that can enhance operational stability and economic feasibility.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100656"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904049","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.2024.100641
Jooho Lee, Seonhong Kim, Jihwan Shin, Jaemoon Yoon, Jinheong Ahn, Minjae Kim
Development of submarine and its safe operational envelope requires an understanding of motion characteristics including emergency rising motion. In this study, the emergency rising motion is investigated using submarine free-running model equipped with ballast systems. The emergency rising test was conducted according to the initial vehicle speed, yaw rate, depth, ballast water discharge ratio and time interval between bow and stern ballast systems. Experimental results reveal that the maximum pitch angle before surface is affected by initial velocity and the operation conditions of ballast systems. In addition, excessive roll occurs after the surface when the submarine passes through the water surface at a negative pitch angle. Furthermore, the system parameters that comprise the emergency rising model are estimated using the collected test data. The identified model is verified by comparing emergency rising simulation with the free-running model test results.
{"title":"Experiment and modeling of submarine emergency rising motion using free-running model","authors":"Jooho Lee, Seonhong Kim, Jihwan Shin, Jaemoon Yoon, Jinheong Ahn, Minjae Kim","doi":"10.1016/j.ijnaoe.2024.100641","DOIUrl":"10.1016/j.ijnaoe.2024.100641","url":null,"abstract":"<div><div>Development of submarine and its safe operational envelope requires an understanding of motion characteristics including emergency rising motion. In this study, the emergency rising motion is investigated using submarine free-running model equipped with ballast systems. The emergency rising test was conducted according to the initial vehicle speed, yaw rate, depth, ballast water discharge ratio and time interval between bow and stern ballast systems. Experimental results reveal that the maximum pitch angle before surface is affected by initial velocity and the operation conditions of ballast systems. In addition, excessive roll occurs after the surface when the submarine passes through the water surface at a negative pitch angle. Furthermore, the system parameters that comprise the emergency rising model are estimated using the collected test data. The identified model is verified by comparing emergency rising simulation with the free-running model test results.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100641"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143164720","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.2025.100643
Yun-jae Kim , Jin Seok Lim , Hae Jong Kim , Sung-Woong Choi
In the present study, technical challenges and their corresponding solutions for each type of foundation—gravity-based, monopile, jacket, tripod, and suction bucket—used in wind turbines were addressed with consideration to different water depths. Along with presenting challenges and their solutions for each foundation, the present study proposed optimizing solutions and methods for addressing these challenges, including numerical approaches and empirical methods derived from field testing. These include enhancing structural stability, improving installation efficiency, and utilizing advanced structural analysis techniques to predict and mitigate environmental impacts. Finally, research cases demonstrating improvements in foundations through shape modifications are summarized. This paper focuses on addressing and proposing an optimal design approach to achieve cost reduction, improved stiffness, and weight minimization. Notably, hybrid foundations incorporating friction wheels achieved a 300% increase in ultimate bearing capacity, while optimization techniques accounting for environmental loads resulted in approximately a 38.24% reduction in foundation weight.
{"title":"A comprehensive review of foundation designs for fixed offshore wind turbines","authors":"Yun-jae Kim , Jin Seok Lim , Hae Jong Kim , Sung-Woong Choi","doi":"10.1016/j.ijnaoe.2025.100643","DOIUrl":"10.1016/j.ijnaoe.2025.100643","url":null,"abstract":"<div><div>In the present study, technical challenges and their corresponding solutions for each type of foundation—gravity-based, monopile, jacket, tripod, and suction bucket—used in wind turbines were addressed with consideration to different water depths. Along with presenting challenges and their solutions for each foundation, the present study proposed optimizing solutions and methods for addressing these challenges, including numerical approaches and empirical methods derived from field testing. These include enhancing structural stability, improving installation efficiency, and utilizing advanced structural analysis techniques to predict and mitigate environmental impacts. Finally, research cases demonstrating improvements in foundations through shape modifications are summarized. This paper focuses on addressing and proposing an optimal design approach to achieve cost reduction, improved stiffness, and weight minimization. Notably, hybrid foundations incorporating friction wheels achieved a 300% increase in ultimate bearing capacity, while optimization techniques accounting for environmental loads resulted in approximately a 38.24% reduction in foundation weight.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100643"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143474584","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.2025.100665
Guoshou Zhao , Heng Liu , Rui Wu , Ning Liang , Linlin Cao
The propulsion pump is widely employed in ocean engineering to generate thrust for surface or underwater vehicles. The cascade provides a simplified way to investigate the flow dynamics inside a propulsion pump considering specific parameters such as solidity and blade stagger. This work develops the foil generation method by in-house code through parametrically controlling the maximum and its position of camber and thickness, the influence of which on the performance obtained by numerical simulation is studied by the multiple statistical regression covering linear and interaction terms. For isolated hydrofoils, the interaction of maximum thickness and its position plays a major role in determining the performance. For cascade configurations with variable foils, besides the thickness interaction terms, other terms influencing lift and drag are not unified for different angles of attack. The solidity insignificantly affects the regression terms. For the cascade with the fixed foils, the solidity, axial velocity, and incidence angle all have an impact on the cascade foil's performance. The statistical loading distributions show that the isolated foil is a typical head-loading type, and the cascade foil is a body-loading type. The cascade cavitation dynamics indicate that a higher solidity and incidence angle would depress the cavitation development owing to the adjacent foil interference. This research aims to provide an instructive guide on pump blade design.
{"title":"Statistical study of cascade hydrodynamics and cavitation dynamics in propulsion pumps","authors":"Guoshou Zhao , Heng Liu , Rui Wu , Ning Liang , Linlin Cao","doi":"10.1016/j.ijnaoe.2025.100665","DOIUrl":"10.1016/j.ijnaoe.2025.100665","url":null,"abstract":"<div><div>The propulsion pump is widely employed in ocean engineering to generate thrust for surface or underwater vehicles. The cascade provides a simplified way to investigate the flow dynamics inside a propulsion pump considering specific parameters such as solidity and blade stagger. This work develops the foil generation method by in-house code through parametrically controlling the maximum and its position of camber and thickness, the influence of which on the performance obtained by numerical simulation is studied by the multiple statistical regression covering linear and interaction terms. For isolated hydrofoils, the interaction of maximum thickness and its position plays a major role in determining the performance. For cascade configurations with variable foils, besides the thickness interaction terms, other terms influencing lift and drag are not unified for different angles of attack. The solidity insignificantly affects the regression terms. For the cascade with the fixed foils, the solidity, axial velocity, and incidence angle all have an impact on the cascade foil's performance. The statistical loading distributions show that the isolated foil is a typical head-loading type, and the cascade foil is a body-loading type. The cascade cavitation dynamics indicate that a higher solidity and incidence angle would depress the cavitation development owing to the adjacent foil interference. This research aims to provide an instructive guide on pump blade design.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100665"},"PeriodicalIF":2.3,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241298","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.2025.100707
Agnieszka Lazarowska
The development of Autonomous Navigation Systems (ANS) constitutes a milestone in the process leading to the achievement of the autonomous operation of different vehicles, such as cars, aircrafts, mobile robots and ships. Obstacle avoidance is a vital task that has to be included in the process of the development of such system. The paper introduces a path planning method to be applied in the Maritime Intelligent Transportation Systems (M-ITS). The method uses the safety indicators such as the Distance at the Closest Point of Approach (DCPA), the Time to the Closest Point of Approach (TCPA), the Bow Crossing Range (BCR) and the Bow Crossing Time (BCT). The method considers the International Regulations for Preventing Collisions at Sea (COLREGs) and safety zones (domains) around target ships. The deterministic nature of the algorithm guarantees the repeatability of solutions for every run of the algorithm with the same input data and very short run-time. The approach was compared with two other algorithms, one deterministic and one heuristic. Results of 100 test cases with different complexity (simple encounters defined in the COLREGs as well as multi-ship encounters with up to 20 target ships) were compared in the paper. The algorithm searches for a solution in a cascade manner, what allows for the achievement of competitive results as compared to other algorithms maintaining short run time. These features allow to apply this collision avoidance (COLAV) method in commercial systems of autonomous ships and Unmanned Surface Vessels (USVs).
{"title":"Safe path planning for autonomous ships based on the point of potential collision concept","authors":"Agnieszka Lazarowska","doi":"10.1016/j.ijnaoe.2025.100707","DOIUrl":"10.1016/j.ijnaoe.2025.100707","url":null,"abstract":"<div><div>The development of Autonomous Navigation Systems (ANS) constitutes a milestone in the process leading to the achievement of the autonomous operation of different vehicles, such as cars, aircrafts, mobile robots and ships. Obstacle avoidance is a vital task that has to be included in the process of the development of such system. The paper introduces a path planning method to be applied in the Maritime Intelligent Transportation Systems (M-ITS). The method uses the safety indicators such as the Distance at the Closest Point of Approach (DCPA), the Time to the Closest Point of Approach (TCPA), the Bow Crossing Range (BCR) and the Bow Crossing Time (BCT). The method considers the International Regulations for Preventing Collisions at Sea (COLREGs) and safety zones (domains) around target ships. The deterministic nature of the algorithm guarantees the repeatability of solutions for every run of the algorithm with the same input data and very short run-time. The approach was compared with two other algorithms, one deterministic and one heuristic. Results of 100 test cases with different complexity (simple encounters defined in the COLREGs as well as multi-ship encounters with up to 20 target ships) were compared in the paper. The algorithm searches for a solution in a cascade manner, what allows for the achievement of competitive results as compared to other algorithms maintaining short run time. These features allow to apply this collision avoidance (COLAV) method in commercial systems of autonomous ships and Unmanned Surface Vessels (USVs).</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100707"},"PeriodicalIF":3.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145614547","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.2025.100709
Yi Eun Kim , Hee Yeong Yang , Yeong Je Kim , Joo Shin Park , Dong Hun Lee , Sang Jin Kim , Do Kyun Kim
This study presents an empirical formula for predicting the ultimate compressive strength of curved plates incorporating welding-induced defects, with the objective of enhancing structural design for Ocean Mobility applications. The proposed formula uniquely considers both initial deflection and welding residual stress, two major sources of imperfection. It introduces the plate slenderness ratio (β) and the flank angle (θ, in radians) as internal variables. It enables the prediction of ultimate strength across eight representative scenarios, defined by combinations of welding direction, loading condition, initial deflection level, and residual stress distribution. The results indicate that welding residual stress can reduce the ultimate strength by up to 10 %, and the proposed formula demonstrates high accuracy with an average deviation within 0.1 % from FEM results. This research improves existing design equations by systematically incorporating the effects of welding defects, and the proposed formula may serve as a reliable tool for accurate ultimate strength assessment in the structural design of welded curved plates.
{"title":"Welding residual stress of curved plate: Development of empirical formula for predicting ultimate compressive strength","authors":"Yi Eun Kim , Hee Yeong Yang , Yeong Je Kim , Joo Shin Park , Dong Hun Lee , Sang Jin Kim , Do Kyun Kim","doi":"10.1016/j.ijnaoe.2025.100709","DOIUrl":"10.1016/j.ijnaoe.2025.100709","url":null,"abstract":"<div><div>This study presents an empirical formula for predicting the ultimate compressive strength of curved plates incorporating welding-induced defects, with the objective of enhancing structural design for Ocean Mobility applications. The proposed formula uniquely considers both initial deflection and welding residual stress, two major sources of imperfection. It introduces the plate slenderness ratio (<em>β</em>) and the flank angle (<em>θ</em>, in radians) as internal variables. It enables the prediction of ultimate strength across eight representative scenarios, defined by combinations of welding direction, loading condition, initial deflection level, and residual stress distribution. The results indicate that welding residual stress can reduce the ultimate strength by up to 10 %, and the proposed formula demonstrates high accuracy with an average deviation within 0.1 % from FEM results. This research improves existing design equations by systematically incorporating the effects of welding defects, and the proposed formula may serve as a reliable tool for accurate ultimate strength assessment in the structural design of welded curved plates.</div></div>","PeriodicalId":14160,"journal":{"name":"International Journal of Naval Architecture and Ocean Engineering","volume":"17 ","pages":"Article 100709"},"PeriodicalIF":3.9,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733057","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}
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