Pub Date : 2025-02-01DOI: 10.1016/j.joes.2023.07.003
Kaiyuan Shi, Renchuan Zhu, Dekang Xu
The challenge of simulating the broad open sea with limited computational resources has long been of interest in ocean engineering research. In view of this issue, this paper proposes a fully nonlinear potential flow method named the spectral coupled boundary element method (SCBEM). By leveraging the approach of domain decomposition, SCBEM achieves significantly reduced computational cost and an order of magnitude increase in computational domain compared to the conventional boundary element method (BEM). The SCBEM encompasses the marine structure with only a tiny BEM domain and employs a high-order spectral layer to simulate the broad water outside the BEM domain. The performance of the SCBEM is evaluated through comparison with the wave damping approach and literature results for regular waves, modulated wave trains, focused waves, and diffraction of a vertical cylinder. The numerical results demonstrate the effectiveness and accuracy of the SCBEM in simulating a wide range of wavelengths and nonlinear wave interactions.
{"title":"A spectral coupled boundary element method for the simulation of nonlinear surface gravity waves","authors":"Kaiyuan Shi, Renchuan Zhu, Dekang Xu","doi":"10.1016/j.joes.2023.07.003","DOIUrl":"10.1016/j.joes.2023.07.003","url":null,"abstract":"<div><div>The challenge of simulating the broad open sea with limited computational resources has long been of interest in ocean engineering research. In view of this issue, this paper proposes a fully nonlinear potential flow method named the spectral coupled boundary element method (SCBEM). By leveraging the approach of domain decomposition, SCBEM achieves significantly reduced computational cost and an order of magnitude increase in computational domain compared to the conventional boundary element method (BEM). The SCBEM encompasses the marine structure with only a tiny BEM domain and employs a high-order spectral layer to simulate the broad water outside the BEM domain. The performance of the SCBEM is evaluated through comparison with the wave damping approach and literature results for regular waves, modulated wave trains, focused waves, and diffraction of a vertical cylinder. The numerical results demonstrate the effectiveness and accuracy of the SCBEM in simulating a wide range of wavelengths and nonlinear wave interactions.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 1","pages":"Pages 123-135"},"PeriodicalIF":13.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45436015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.joes.2023.02.001
Iman Ramzanpoor , Martin Nuernberg , Longbin Tao
This paper presents a fully coupled aero-hydro-servo elastic analysis of a 10MW offshore wind turbine supported by a tension leg buoy (TLB) platform, with a taut mooring system. The study investigates the TLB's dynamic response characteristics under the northern North Sea environmental conditions with water depths of 110 metres, comparing the performance of steel, polyester, and nylon mooring line configurations. Innovating floating wind turbines requires a cost-effective system that achieves reliable performance in operational and survival conditions. The innovative system should compete with other existing FOWT types and fixed-bottom offshore wind turbines in terms of LCOE. The dynamic responses of the relatively less complex TLB platform in terms of construction and installation showed small motion and accelerations for all available mooring materials from the current supply chain, enabling the wind turbine to be installed without significant modifications to their control systems. The mooring materials' elasticity is essential in the system achieving motion response.
{"title":"Coupled aero-hydro-servo-elastic analysis of 10MW TLB floating offshore wind turbine","authors":"Iman Ramzanpoor , Martin Nuernberg , Longbin Tao","doi":"10.1016/j.joes.2023.02.001","DOIUrl":"10.1016/j.joes.2023.02.001","url":null,"abstract":"<div><div>This paper presents a fully coupled aero-hydro-servo elastic analysis of a 10MW offshore wind turbine supported by a tension leg buoy (TLB) platform, with a taut mooring system. The study investigates the TLB's dynamic response characteristics under the northern North Sea environmental conditions with water depths of 110 metres, comparing the performance of steel, polyester, and nylon mooring line configurations. Innovating floating wind turbines requires a cost-effective system that achieves reliable performance in operational and survival conditions. The innovative system should compete with other existing FOWT types and fixed-bottom offshore wind turbines in terms of LCOE. The dynamic responses of the relatively less complex TLB platform in terms of construction and installation showed small motion and accelerations for all available mooring materials from the current supply chain, enabling the wind turbine to be installed without significant modifications to their control systems. The mooring materials' elasticity is essential in the system achieving motion response.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 1","pages":"Pages 29-58"},"PeriodicalIF":13.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44196098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.joes.2022.05.015
Gang Tang , Jinman Lei , Haohao Du , Baoheng Yao , Weidong Zhu , Xiong Hu
The parallel stabilized platform is an important equipment to ensure the stability of marine operations, which can effectively mitigate collisions of lifted goods. The 3UPU_UP parallel stabilized platform system is proposed, and the kinematics and dynamics of the 3UPU_UP parallel stabilized platform are researched, where U denotes universal joint; P denotes prismatic joint. The platform motion can be realized by controlling the actuators to realize compensation ship motion. While conventional control algorithms are difficult to cope with complex nonlinear systems, the optimization control method has been proposed. Based on the back propagation (BP) neural network proportional-integral-derivative (PID) controller, the particle swarm optimization (PSO) is combined with the BP neural network, and the combined PSO-BP PID controller optimization algorithm is introduced into the servo control system. Compared with classic PID and BP PID, the overshoot of PSO-BP PID to the response of step signal is reduced by 10.2% and 11.48%, respectively, and 0.36s and 0.17s reduce the time required to reach stable states. By comparing the reduction of the error under various sea conditions, the upper platform tracking error curve is flatter under a PID controller based on PSO-BP, the tracking motion is closer to the theoretical value and the control accuracy is improved. The maximum tracking error of the upper platform is smaller, the overall motion vibration of the platform is reduced, and the anti-interference ability is enhanced. The PSO-BP PID controller for wave compensated platform servo system control is more reasonable, more adaptable to the complex and changing environment.
{"title":"Proportional-integral-derivative controller optimization by particle swarm optimization and back propagation neural network for a parallel stabilized platform in marine operations","authors":"Gang Tang , Jinman Lei , Haohao Du , Baoheng Yao , Weidong Zhu , Xiong Hu","doi":"10.1016/j.joes.2022.05.015","DOIUrl":"10.1016/j.joes.2022.05.015","url":null,"abstract":"<div><div>The parallel stabilized platform is an important equipment to ensure the stability of marine operations, which can effectively mitigate collisions of lifted goods. The 3UPU_UP parallel stabilized platform system is proposed, and the kinematics and dynamics of the 3UPU_UP parallel stabilized platform are researched, where U denotes universal joint; P denotes prismatic joint. The platform motion can be realized by controlling the actuators to realize compensation ship motion. While conventional control algorithms are difficult to cope with complex nonlinear systems, the optimization control method has been proposed. Based on the back propagation (BP) neural network proportional-integral-derivative (PID) controller, the particle swarm optimization (PSO) is combined with the BP neural network, and the combined PSO-BP PID controller optimization algorithm is introduced into the servo control system. Compared with classic PID and BP PID, the overshoot of PSO-BP PID to the response of step signal is reduced by 10.2% and 11.48%, respectively, and 0.36s and 0.17s reduce the time required to reach stable states. By comparing the reduction of the error under various sea conditions, the upper platform tracking error curve is flatter under a PID controller based on PSO-BP, the tracking motion is closer to the theoretical value and the control accuracy is improved. The maximum tracking error of the upper platform is smaller, the overall motion vibration of the platform is reduced, and the anti-interference ability is enhanced. The PSO-BP PID controller for wave compensated platform servo system control is more reasonable, more adaptable to the complex and changing environment.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 1","pages":"Pages 1-10"},"PeriodicalIF":13.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48600099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.joes.2023.10.003
Yihong Li, Zhiqiang Hu
Offshore oil and gas facilities have been developed for over a century. The current exploration, development, and mining technologies are already perfect. However, the offshore oil and gas facilities in the world's major offshore oil-producing countries face serious aging challenges and many are overdue for service. Moreover, many oil and gas platforms are in urgent need of decommissioning. The cost of decommissioning is one of the most concerning issues for energy companies and governments. This study compared two different approaches to cost assessment models built by using United Kingdom Continental Shelf (UKCS) decommissioned platforms: a model constructed using a popular top-down approach, and one created by a novel bottom-up approach. Both models use the completed decommissioning projects in the UKCS area as research and verification resources. According to the results, although the cost assessment model constructed using the bottom-up method is challenging, it has higher accuracy and more robust versatility. The top-down approach model is more suitable for governments and energy companies to make rough assessments of the market and projects. The bottom-up approach model is more suitable for a more detailed cost assessment of the decommissioning of individual facilities and can be integrated with results from other assessment models (such as risk and impact assessment models) to obtain more accurate cost assessment results. Both approaches have great room for improvement at present, and further integration of disciplines may be the key to breakthroughs in this field.
{"title":"Comparative study of two cost assessment approaches to models for offshore oil and gas platform decommissioning","authors":"Yihong Li, Zhiqiang Hu","doi":"10.1016/j.joes.2023.10.003","DOIUrl":"10.1016/j.joes.2023.10.003","url":null,"abstract":"<div><div>Offshore oil and gas facilities have been developed for over a century. The current exploration, development, and mining technologies are already perfect. However, the offshore oil and gas facilities in the world's major offshore oil-producing countries face serious aging challenges and many are overdue for service. Moreover, many oil and gas platforms are in urgent need of decommissioning. The cost of decommissioning is one of the most concerning issues for energy companies and governments. This study compared two different approaches to cost assessment models built by using United Kingdom Continental Shelf (UKCS) decommissioned platforms: a model constructed using a popular top-down approach, and one created by a novel bottom-up approach. Both models use the completed decommissioning projects in the UKCS area as research and verification resources. According to the results, although the cost assessment model constructed using the bottom-up method is challenging, it has higher accuracy and more robust versatility. The top-down approach model is more suitable for governments and energy companies to make rough assessments of the market and projects. The bottom-up approach model is more suitable for a more detailed cost assessment of the decommissioning of individual facilities and can be integrated with results from other assessment models (such as risk and impact assessment models) to obtain more accurate cost assessment results. Both approaches have great room for improvement at present, and further integration of disciplines may be the key to breakthroughs in this field.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 1","pages":"Pages 136-149"},"PeriodicalIF":13.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135761809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.joes.2023.04.001
Yandong Hu, Yifan Zhao, Min Zhao, Miaolin Feng
Due to sophistications in experimental studies, the implosions in chain reaction, also named as sympathetic implosions, demand numerical models to understand the phenomena caused by various impacts to the primary sphere. We developed a 3D air-solid-water model considering the influence of brittle sphere failures of two alumina spheres to simulate the outbreak of the sympathetic implosion in the seawater of 114 MPa. According to the triggering mode, two cases of simultaneous implosions and five cases of sympathetic implosions of a double-sphere were numerically studied. We found that the induced fracture of the secondary sphere happened before the outbreak of the positive pressure wave, i.e., the induced fracture is caused by the uneven pressure around the sphere lower than the hydrostatic pressure. To our knowledge, the present paper is the first report on the early fracture of the secondary solid sphere in sympathetic implosions. With various triggering modes of the primary sphere, the secondary fractures are all induced at the proximal side and extend to the other side. The formed ring-shaped implosion cores are caused by individual fracture mode. The shifting of the two implosion cores eventually affects the pressure pulses at a position. A higher or similar values of the secondary pulse are found closely related to the double sphere's fracture modes, i.e., related to the triggering modes of the local impacts. This work help to estimate the damage of the sympathetic implosion to the surroundings, and prevent further implosions by understanding spatial superposition of a series of pulses.
{"title":"Double ceramic sphere's sympathetic implosions triggered by local impacts","authors":"Yandong Hu, Yifan Zhao, Min Zhao, Miaolin Feng","doi":"10.1016/j.joes.2023.04.001","DOIUrl":"10.1016/j.joes.2023.04.001","url":null,"abstract":"<div><div>Due to sophistications in experimental studies, the implosions in chain reaction, also named as sympathetic implosions, demand numerical models to understand the phenomena caused by various impacts to the primary sphere. We developed a 3D air-solid-water model considering the influence of brittle sphere failures of two alumina spheres to simulate the outbreak of the sympathetic implosion in the seawater of 114 MPa. According to the triggering mode, two cases of simultaneous implosions and five cases of sympathetic implosions of a double-sphere were numerically studied. We found that the induced fracture of the secondary sphere happened before the outbreak of the positive pressure wave, i.e., the induced fracture is caused by the uneven pressure around the sphere lower than the hydrostatic pressure. To our knowledge, the present paper is the first report on the early fracture of the secondary solid sphere in sympathetic implosions. With various triggering modes of the primary sphere, the secondary fractures are all induced at the proximal side and extend to the other side. The formed ring-shaped implosion cores are caused by individual fracture mode. The shifting of the two implosion cores eventually affects the pressure pulses at a position. A higher or similar values of the secondary pulse are found closely related to the double sphere's fracture modes, i.e., related to the triggering modes of the local impacts. This work help to estimate the damage of the sympathetic implosion to the surroundings, and prevent further implosions by understanding spatial superposition of a series of pulses.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 1","pages":"Pages 59-69"},"PeriodicalIF":13.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43832983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.joes.2023.10.004
Min-Ho Park , Jae-Jung Hur , Won-Ju Lee
To this day, diesel generator (DG) continues to play an indispensable role in all industries and smart engines and engines with eco-friendly technologies are being developed. However, with the advent of the unmanned automation era, countermeasures are required when DG sensors are non-functional. Therefore, an optimized AI model for backing up sensor data, which is necessary for the safety of smart engines equipped with eco-friendly facilities, was developed. To develop an AI model for this purpose, an experiment was conducted to obtain the engine and emission data to be used and 11 models were created. By predicting 16 variables related to the engine performance and emissions using a total of five sensor data, including three sensors essential for the engine safety, the proposed AI model could back up data when some sensors failed. Moreover, various hyperparameter tunings were applied and compared to maximize the model performance. Consequently, the decision tree (DT)-based models and genetic algorithm showed a good performance, and the weighted average of ensemble (DT) model showed the best performance with R2 value of 0.9981, and a SMAPE value of 0.7244. Additionally, to confirm the generalization performance of the model, the prediction performance of the models was measured using new data, and the blending of ensemble (ALL) model had the best performance with R2 value of 0.9266, and a SMAPE value of 5.585. Finally, the application of the concept used to develop the AI model and the future direction of the work were discussed.
{"title":"Prediction of diesel generator performance and emissions using minimal sensor data and analysis of advanced machine learning techniques","authors":"Min-Ho Park , Jae-Jung Hur , Won-Ju Lee","doi":"10.1016/j.joes.2023.10.004","DOIUrl":"10.1016/j.joes.2023.10.004","url":null,"abstract":"<div><div>To this day, diesel generator (DG) continues to play an indispensable role in all industries and smart engines and engines with eco-friendly technologies are being developed. However, with the advent of the unmanned automation era, countermeasures are required when DG sensors are non-functional. Therefore, an optimized AI model for backing up sensor data, which is necessary for the safety of smart engines equipped with eco-friendly facilities, was developed. To develop an AI model for this purpose, an experiment was conducted to obtain the engine and emission data to be used and 11 models were created. By predicting 16 variables related to the engine performance and emissions using a total of five sensor data, including three sensors essential for the engine safety, the proposed AI model could back up data when some sensors failed. Moreover, various hyperparameter tunings were applied and compared to maximize the model performance. Consequently, the decision tree (DT)-based models and genetic algorithm showed a good performance, and the weighted average of ensemble (DT) model showed the best performance with R<sup>2</sup> value of 0.9981, and a SMAPE value of 0.7244. Additionally, to confirm the generalization performance of the model, the prediction performance of the models was measured using new data, and the blending of ensemble (ALL) model had the best performance with R<sup>2</sup> value of 0.9266, and a SMAPE value of 5.585. Finally, the application of the concept used to develop the AI model and the future direction of the work were discussed.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 1","pages":"Pages 150-168"},"PeriodicalIF":13.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136160570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.joes.2022.06.005
Mohamed T. Elnabwy , Emad Elbeltagi , Mahmoud M. El Banna , Mohamed Y. Elsheikh , Ibrahim Motawa , Jong Wan Hu , Mosbeh R. Kaloop
Sedimentation is one of the most critical environmental issues facing harbors’ authorities that results in significant maintenance and dredging costs. Thus, it is essential to plan and manage the harbors in harmony with both the environmental and economic aspects to support Integrated Coastal Structures Management (ICSM). Harbors' layout and the permeability of protection structures like breakwaters affect the sediment transport within harbors’ basins. Using a multi-step relational research framework, this study aims to design a novel prediction model for estimating the sedimentation quantities in harbors through a comparative approach based on artificial intelligence (AI) algorithms. First, one hundred simulations for different harbor layouts and various breakwater characteristics were numerically performed using a coastal modeling system (CMS) for generating the dataset to train and validate the proposed AI-based models. Second, three AI approaches namely: Support Vector Regression (SVR), Gaussian Process Regression (GPR), and Artificial Neural Networks (ANN) were developed to predict sedimentation quantities. Third, a comparison between the developed models was conducted using quality assessment criteria to evaluate their performance and choose the best one. Fourth, a sensitivity analysis was performed to provide insights into the factors affecting sedimentation. Lastly, a decision support tool was developed to predict harbors' sedimentation quantities. Results showed that the ANN model outperforms other models with mean absolute percentage error (MAPE) equals 4%. Furthermore, sensitivity analysis demonstrated that the main breakwater inclination angle, porosity, and harbor basin width affect significantly sediment transport. This research makes a significant contribution to the management of coastal structures by developing an AI data-driven framework that is beneficial for harbors' authorities. Ultimately, the developed decision-support AI tool could be used to predict harbors' sedimentation quantities in an easy, cheap, accurate, and practical manner compared to physical modeling which is time-consuming and costly.
{"title":"Conceptual prediction of harbor sedimentation quantities using AI approaches to support integrated coastal structures management","authors":"Mohamed T. Elnabwy , Emad Elbeltagi , Mahmoud M. El Banna , Mohamed Y. Elsheikh , Ibrahim Motawa , Jong Wan Hu , Mosbeh R. Kaloop","doi":"10.1016/j.joes.2022.06.005","DOIUrl":"10.1016/j.joes.2022.06.005","url":null,"abstract":"<div><div>Sedimentation is one of the most critical environmental issues facing harbors’ authorities that results in significant maintenance and dredging costs. Thus, it is essential to plan and manage the harbors in harmony with both the environmental and economic aspects to support Integrated Coastal Structures Management (ICSM). Harbors' layout and the permeability of protection structures like breakwaters affect the sediment transport within harbors’ basins. Using a multi-step relational research framework, this study aims to design a novel prediction model for estimating the sedimentation quantities in harbors through a comparative approach based on artificial intelligence (AI) algorithms. First, one hundred simulations for different harbor layouts and various breakwater characteristics were numerically performed using a coastal modeling system (CMS) for generating the dataset to train and validate the proposed AI-based models. Second, three AI approaches namely: Support Vector Regression (SVR), Gaussian Process Regression (GPR), and Artificial Neural Networks (ANN) were developed to predict sedimentation quantities. Third, a comparison between the developed models was conducted using quality assessment criteria to evaluate their performance and choose the best one. Fourth, a sensitivity analysis was performed to provide insights into the factors affecting sedimentation. Lastly, a decision support tool was developed to predict harbors' sedimentation quantities. Results showed that the ANN model outperforms other models with mean absolute percentage error (MAPE) equals 4%. Furthermore, sensitivity analysis demonstrated that the main breakwater inclination angle, porosity, and harbor basin width affect significantly sediment transport. This research makes a significant contribution to the management of coastal structures by developing an AI data-driven framework that is beneficial for harbors' authorities. Ultimately, the developed decision-support AI tool could be used to predict harbors' sedimentation quantities in an easy, cheap, accurate, and practical manner compared to physical modeling which is time-consuming and costly.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 1","pages":"Pages 11-21"},"PeriodicalIF":13.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47578593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.joes.2025.01.001
Ling Liu , Ke Zeng , Jun Ding , Qibin Wang , Shuxia Bu , Cheng Cheng
The slamming phenomenon is a highly concerned fluid structure coupling problem in the engineering field. Based on the original MLM(Modified Logvinovich Mode), an explicit solution for the higher-order MLM slamming model is derived. The second-order velocity potential, pressure distribution and slamming force can be quickly evaluated. The derived second-order MLM slamming model is compared with the first-order solution and numerical results. Sensitivity analysis reveals that for small angles (), both first-order and second-order MLM solutions can provide sufficiently accurate slamming solutions. However, for larger deadrise angles (), the second-order solution becomes increasingly significant. The excess second-order pressure cannot be ignored, achieving a proportion. The accuracy of the first-order MLM solutions cannot be guaranteed for large cases, with an error of up to , with the difference in slamming force growing more pronounced as increases. For larger values, the second-order MLM solution is more consistent with the numerical results, while the accuracy of the first-order MLM solution decreases. The study concludes that the second-order MLM model expands the applicability of the MLM slamming model to larger deadrise angles, providing a new method for rapid assessment of slamming problems in structures with large .
{"title":"A two-dimensional high-order explicit analytical solution model for symmetric wedges entering water","authors":"Ling Liu , Ke Zeng , Jun Ding , Qibin Wang , Shuxia Bu , Cheng Cheng","doi":"10.1016/j.joes.2025.01.001","DOIUrl":"10.1016/j.joes.2025.01.001","url":null,"abstract":"<div><div>The slamming phenomenon is a highly concerned fluid structure coupling problem in the engineering field. Based on the original MLM(Modified Logvinovich Mode), an explicit solution for the higher-order MLM slamming model is derived. The second-order velocity potential, pressure distribution and slamming force can be quickly evaluated. The derived second-order MLM slamming model is compared with the first-order solution and numerical results. Sensitivity analysis reveals that for small angles (<span><math><mrow><mi>β</mi><mo>≤</mo><msup><mn>15</mn><mo>∘</mo></msup></mrow></math></span>), both first-order and second-order MLM solutions can provide sufficiently accurate slamming solutions. However, for larger deadrise angles (<span><math><mrow><mi>β</mi><mo>></mo><msup><mn>15</mn><mo>∘</mo></msup></mrow></math></span>), the second-order solution becomes increasingly significant. The excess second-order pressure cannot be ignored, achieving a <span><math><mrow><mn>60</mn><mo>%</mo></mrow></math></span> proportion. The accuracy of the first-order MLM solutions cannot be guaranteed for large <span><math><mi>β</mi></math></span> cases, with an error of up to <span><math><mrow><mn>48</mn><mo>%</mo></mrow></math></span>, with the difference in slamming force growing more pronounced as <span><math><mi>β</mi></math></span> increases. For larger <span><math><mi>β</mi></math></span> values, the second-order MLM solution is more consistent with the numerical results, while the accuracy of the first-order MLM solution decreases. The study concludes that the second-order MLM model expands the applicability of the MLM slamming model to larger deadrise angles, providing a new method for rapid assessment of slamming problems in structures with large <span><math><mi>β</mi></math></span>.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 1","pages":"Pages 109-122"},"PeriodicalIF":13.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143144177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cargo liquefaction is still the biggest causes of casualties during its sea transportation. To understand the liquefaction mechanism deeply, research of moisture migration characteristics of liquefiable cargo is the priority. Closer to the actual transportation conditions of iron ore, unsaturated undrained, saturated undrained and saturated drained experiments were all carried out. Effects of ship motion accelerations, frequencies and sample densities were also taken into account. Results indicate that the largest drainage happens in the first ten minutes when drained, and accounts for 75.3% of the total volume. The external loads have a little promotion for the drainage. The pore water pressure dissipates quickly and its value goes below zero. When undrained, the water would migrates upward and the middle part have a relative higher water content. The pore water pressure accumulates and increases quickly in the first 50–100 s, and also the middle part has the largest increase of pore water pressure. A larger motion acceleration could enhance the accumulation of the pore water pressure and the water migration. There are critical motion frequencies, under which the accumulation of the pore water pressure and the water migration become obvious. For the sample with a higher density, the accumulation of the pore water pressure and the ability of water migration are all bounded. This study could be provided as an useful reference to reveal the liquefaction mechanism.
{"title":"An experimental study on the moisture migration characteristics of liquefiable iron ore","authors":"Jianwei Zhang , Shiji Yin , Weiwen Qian , Deqing Yang","doi":"10.1016/j.joes.2023.07.005","DOIUrl":"10.1016/j.joes.2023.07.005","url":null,"abstract":"<div><div>Cargo liquefaction is still the biggest causes of casualties during its sea transportation. To understand the liquefaction mechanism deeply, research of moisture migration characteristics of liquefiable cargo is the priority. Closer to the actual transportation conditions of iron ore, unsaturated undrained, saturated undrained and saturated drained experiments were all carried out. Effects of ship motion accelerations, frequencies and sample densities were also taken into account. Results indicate that the largest drainage happens in the first ten minutes when drained, and accounts for 75.3% of the total volume. The external loads have a little promotion for the drainage. The pore water pressure dissipates quickly and its value goes below zero. When undrained, the water would migrates upward and the middle part have a relative higher water content. The pore water pressure accumulates and increases quickly in the first 50–100 s, and also the middle part has the largest increase of pore water pressure. A larger motion acceleration could enhance the accumulation of the pore water pressure and the water migration. There are critical motion frequencies, under which the accumulation of the pore water pressure and the water migration become obvious. For the sample with a higher density, the accumulation of the pore water pressure and the ability of water migration are all bounded. This study could be provided as an useful reference to reveal the liquefaction mechanism.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 1","pages":"Pages 169-179"},"PeriodicalIF":13.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41967186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-01DOI: 10.1016/j.joes.2023.06.001
Yiwei Zhang, Rongxin Cui, Fei Deng
The present study investigated the effect of geometrical and non-geometrical parameters on the thrust performance of a pump-valve propulsion device consisting of a Coanda effect valve (CEV) and a pump. A more accurate theoretical model was also developed to predict the thrust of the pump-valve device. Firstly, a rough thrust model was developed based on existing theory to predict the thrust and energy loss generated by the pump-valve device under different exit and nozzle areas. Considering the limitations of the theoretical analysis, numerical simulations were carried out to evaluate the effect of various geometrical and non-geometrical parameters, including nozzle shape, nozzle area, control port width, exit area, inlet flow rate, etc., on the thrust performance of the CEV and the pump-valve device. Due to the margin between simulation thrusts and theoretical thrusts, we built an experimental platform and carried out relevant experiments. The experimental data verified the simulation results, and on this basis, the original thrust prediction model was corrected.
{"title":"Geometric and non-geometric impact on Coanda effect propulsion device for UUV application","authors":"Yiwei Zhang, Rongxin Cui, Fei Deng","doi":"10.1016/j.joes.2023.06.001","DOIUrl":"10.1016/j.joes.2023.06.001","url":null,"abstract":"<div><div>The present study investigated the effect of geometrical and non-geometrical parameters on the thrust performance of a pump-valve propulsion device consisting of a Coanda effect valve (CEV) and a pump. A more accurate theoretical model was also developed to predict the thrust of the pump-valve device. Firstly, a rough thrust model was developed based on existing theory to predict the thrust and energy loss generated by the pump-valve device under different exit and nozzle areas. Considering the limitations of the theoretical analysis, numerical simulations were carried out to evaluate the effect of various geometrical and non-geometrical parameters, including nozzle shape, nozzle area, control port width, exit area, inlet flow rate, etc., on the thrust performance of the CEV and the pump-valve device. Due to the margin between simulation thrusts and theoretical thrusts, we built an experimental platform and carried out relevant experiments. The experimental data verified the simulation results, and on this basis, the original thrust prediction model was corrected.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 1","pages":"Pages 70-87"},"PeriodicalIF":13.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44538285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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