Pub Date : 2025-07-28DOI: 10.1016/j.joes.2025.07.002
Kacper Cerek, Elnaz Hadjiloo, Jürgen Grabe, Duy Anh Dao
Establishing renewables on a floating platform in the deep sea needs secure anchoring to the seabed, commonly achieved with drag embedment anchors (DEAs). The conventional design process relies heavily on empirical testing and is often time and resource-intensive, potentially leading to suboptimal designs. This research aims to overcome these limitations by applying an evolutionary optimization algorithm to existing analytical solutions for DEAs, identifying optimal anchor fluke and shank lengths. By leveraging an optimization strategy, we aim to enhance the design process while diminishing the dependency on exhaustive physical testing and high computational cost. We employ the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) to optimize anchor shapes, with a focus on three key objectives: maximizing embedment depth and bearing capacity, and minimizing anchor volume. The methodology presents a Pareto front, encompassing all optimal solutions based on the formulated objectives, and demonstrates the efficiency of NSGA-II as a tool for optimizing anchor shapes.
{"title":"Optimization of drag embedment anchors applying multi-objective evolutionary algorithm NSGA-II","authors":"Kacper Cerek, Elnaz Hadjiloo, Jürgen Grabe, Duy Anh Dao","doi":"10.1016/j.joes.2025.07.002","DOIUrl":"10.1016/j.joes.2025.07.002","url":null,"abstract":"<div><div>Establishing renewables on a floating platform in the deep sea needs secure anchoring to the seabed, commonly achieved with drag embedment anchors (DEAs). The conventional design process relies heavily on empirical testing and is often time and resource-intensive, potentially leading to suboptimal designs. This research aims to overcome these limitations by applying an evolutionary optimization algorithm to existing analytical solutions for DEAs, identifying optimal anchor fluke and shank lengths. By leveraging an optimization strategy, we aim to enhance the design process while diminishing the dependency on exhaustive physical testing and high computational cost. We employ the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) to optimize anchor shapes, with a focus on three key objectives: maximizing embedment depth and bearing capacity, and minimizing anchor volume. The methodology presents a Pareto front, encompassing all optimal solutions based on the formulated objectives, and demonstrates the efficiency of NSGA-II as a tool for optimizing anchor shapes.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 6","pages":"Pages 1019-1030"},"PeriodicalIF":11.8,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-07-21DOI: 10.1016/j.joes.2025.07.003
Yan Kai , Pengfei Xu , Hailong Lin , Chengrui Sun , Min Zhao , Guangqian Du
The ever-expanding frontier of applications demands that mobile vehicles navigate challenging, complex, and rugged terrains, as well as diverse environments. In this paper, we presented the novel design of an autonomous amphibious vehicle, driven by Archimedean screw mechanisms. Hydrodynamic simulations were conducted to analyze the propulsive characteristics of screw mechanisms in water. Particularly, an innovative screw-propeller integrated structure was proposed. At a rotation speed of 1000 rpm, the generated thrust of the integrated structure increased by 50 % compared with the original screw, indicating a significant improvement in propulsion performance. Simultaneously, we analyzed its contact with the terrain by using the discrete element method. The process was simulated through a co-simulation involving multi-body dynamics, which presented an analytical method for investigating vehicle-terrain contact mechanics. Finally, a series of performance and field experiments were carried out. The vehicle successfully traversed various terrains including sandy, gravel, and grass roads, overcoming a 5 cm high obstacle. Furthermore, it autonomously executed offshore and landing movements, and showcased excellent amphibious trafficability at the coast. Overall, our research provides valuable insights into the development of autonomous screw-driven vehicles, offering a wide range of application prospects.
{"title":"CSUB: Design and modeling of an autonomous screw-driven amphibious vehicle","authors":"Yan Kai , Pengfei Xu , Hailong Lin , Chengrui Sun , Min Zhao , Guangqian Du","doi":"10.1016/j.joes.2025.07.003","DOIUrl":"10.1016/j.joes.2025.07.003","url":null,"abstract":"<div><div>The ever-expanding frontier of applications demands that mobile vehicles navigate challenging, complex, and rugged terrains, as well as diverse environments. In this paper, we presented the novel design of an autonomous amphibious vehicle, driven by Archimedean screw mechanisms. Hydrodynamic simulations were conducted to analyze the propulsive characteristics of screw mechanisms in water. Particularly, an innovative screw-propeller integrated structure was proposed. At a rotation speed of 1000 rpm, the generated thrust of the integrated structure increased by 50 % compared with the original screw, indicating a significant improvement in propulsion performance. Simultaneously, we analyzed its contact with the terrain by using the discrete element method. The process was simulated through a co-simulation involving multi-body dynamics, which presented an analytical method for investigating vehicle-terrain contact mechanics. Finally, a series of performance and field experiments were carried out. The vehicle successfully traversed various terrains including sandy, gravel, and grass roads, overcoming a 5 cm high obstacle. Furthermore, it autonomously executed offshore and landing movements, and showcased excellent amphibious trafficability at the coast. Overall, our research provides valuable insights into the development of autonomous screw-driven vehicles, offering a wide range of application prospects.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 6","pages":"Pages 1031-1045"},"PeriodicalIF":11.8,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An analysis is performed for the three-dimensional stagnation point flow of magnetized tangent hyperbolic fluid over a rotating disk of variable thickness. The viscosity and thermal conductivity of the fluid are presumed to depend on the temperature. Moreover, the impact of various physical parameters i.e., variable dynamical viscosity, variable thermal conductivity, velocity ratio, thermal stratification, Weissenberg number, Biot number and Eckert number are considered. Here we use the intuitionistic fuzzy set (IFS), which is an extension of fuzzy set, to study the flow and heat transfer analysis. IFS is a better tool for deal with uncertainty and complex modelling. The transformed ODEs are changed into intuitionistic fuzzy differential equations (IFDEs) and then solved by applying -cut method, and the notion of triangular intuitionistic fuzzy number (TIFN). The outcomes attained from the solutions of IFDEs are depicted by figures, and results are reliable as calculated with the numerical technique “bvp4c”. The study reports that a rise of 40.68% in local Nusselt number (LNN) is seen when the velocity ratio parameter is raised from 0.1 to 0.4, whereas a rise of 5.26% is noted when the variable thermal conductivity parameter is increased from -0.5 to 0.5.
{"title":"Magnetohydrodynamics stagnation point flow of tangent hyperbolic fluid over a non-flat rotating disk in intuitionistic fuzzy environment","authors":"Priya Bartwal , B.P. Joshi , Himanshu Upreti , Alok Kumar Pandey , Dharmendra Tripathi","doi":"10.1016/j.joes.2025.07.001","DOIUrl":"10.1016/j.joes.2025.07.001","url":null,"abstract":"<div><div>An analysis is performed for the three-dimensional stagnation point flow of magnetized tangent hyperbolic fluid over a rotating disk of variable thickness. The viscosity and thermal conductivity of the fluid are presumed to depend on the temperature. Moreover, the impact of various physical parameters i.e., variable dynamical viscosity, variable thermal conductivity, velocity ratio, thermal stratification, Weissenberg number, Biot number and Eckert number are considered. Here we use the intuitionistic fuzzy set (IFS), which is an extension of fuzzy set, to study the flow and heat transfer analysis. IFS is a better tool for deal with uncertainty and complex modelling. The transformed ODEs are changed into intuitionistic fuzzy differential equations (IFDEs) and then solved by applying <span><math><mrow><mo>(</mo><mi>α</mi><mo>,</mo><mi>β</mi><mo>)</mo></mrow></math></span>-cut method, and the notion of triangular intuitionistic fuzzy number (TIFN). The outcomes attained from the solutions of IFDEs are depicted by figures, and results are reliable as calculated with the numerical technique “bvp4c”. The study reports that a rise of 40.68% in local Nusselt number (LNN) is seen when the velocity ratio parameter is raised from 0.1 to 0.4, whereas a rise of 5.26% is noted when the variable thermal conductivity parameter is increased from -0.5 to 0.5.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 6","pages":"Pages 1002-1018"},"PeriodicalIF":11.8,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145469015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-06-01DOI: 10.1016/j.joes.2024.07.001
Yu Yang, Tao Peng, Shijun Liao, Jing Li
Real-time prediction of ship motions is crucial for ensuring the safety of offshore activities. In this study, we investigate the performance of the reservoir computing (RC) model in predicting the motions of a ship sailing in irregular waves, comparing it with the long short-term memory (LSTM), bidirectional LSTM (BiLSTM), and gated recurrent unit (GRU) networks. The model tests are carried out in a towing tank to generate the datasets for training and testing the machine learning models. First, we explore the performance of machine learning models trained solely on motion data. It is found that the RC model outperforms the LSTM, BiLSTM, and GRU networks in both accuracy and efficiency for predicting ship motions. Besides, we investigate the performance of the RC model trained using the historical motion and wave elevation data. It is shown that, compared with the RC model trained solely on motion data, the RC model trained on the motion and wave elevation data can significantly improve the motion prediction accuracy. This study validates the effectiveness and efficiency of the RC model in ship motion prediction during sailing and highlights the utility of wave elevation data in enhancing the RC model’s prediction accuracy.
{"title":"Real-time prediction of ship motions based on the reservoir computing model","authors":"Yu Yang, Tao Peng, Shijun Liao, Jing Li","doi":"10.1016/j.joes.2024.07.001","DOIUrl":"10.1016/j.joes.2024.07.001","url":null,"abstract":"<div><div>Real-time prediction of ship motions is crucial for ensuring the safety of offshore activities. In this study, we investigate the performance of the reservoir computing (RC) model in predicting the motions of a ship sailing in irregular waves, comparing it with the long short-term memory (LSTM), bidirectional LSTM (BiLSTM), and gated recurrent unit (GRU) networks. The model tests are carried out in a towing tank to generate the datasets for training and testing the machine learning models. First, we explore the performance of machine learning models trained solely on motion data. It is found that the RC model outperforms the LSTM, BiLSTM, and GRU networks in both accuracy and efficiency for predicting ship motions. Besides, we investigate the performance of the RC model trained using the historical motion and wave elevation data. It is shown that, compared with the RC model trained solely on motion data, the RC model trained on the motion and wave elevation data can significantly improve the motion prediction accuracy. This study validates the effectiveness and efficiency of the RC model in ship motion prediction during sailing and highlights the utility of wave elevation data in enhancing the RC model’s prediction accuracy.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 3","pages":"Pages 379-395"},"PeriodicalIF":13.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141852060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-06-01DOI: 10.1016/j.joes.2023.10.001
Kunpeng Chen , Mengmeng Zhang , Shixiao Fu , Bing Zhao , Chunmiao Luo
Nonbonded flexible pipes consist of polymer materials that experience stress relaxation at high temperatures, which ultimately affects the sealing performance of end sealing systems. To assess stress relaxation curves under varying temperatures and pre-strains, this paper conducts both tensile and stress relaxation tests on PVDF materials. To describe the stress relaxation characteristics of these materials, the Prony series is utilized. In order to identify the parameters of the series, the paper employs the Levenberg-Marquardt method of nonlinear regression. A finite element model is established to verify the accuracy of the parameter identification method. Subsequently, the paper establishes a two-dimensional axisymmetric finite element model of the sealing system in the end fitting, while taking into account fluid pressure inside the pipeline using a pressure penetration method. The impact of stress relaxation on the sealing performance is then discussed. Finally, the paper alters the coefficients of the Prony series to explore their significance on the sealing performance of the sealing system.
{"title":"A numerical model for stress relaxation analysis of sealing systems in nonbonded pipe end fittings","authors":"Kunpeng Chen , Mengmeng Zhang , Shixiao Fu , Bing Zhao , Chunmiao Luo","doi":"10.1016/j.joes.2023.10.001","DOIUrl":"10.1016/j.joes.2023.10.001","url":null,"abstract":"<div><div>Nonbonded flexible pipes consist of polymer materials that experience stress relaxation at high temperatures, which ultimately affects the sealing performance of end sealing systems. To assess stress relaxation curves under varying temperatures and pre-strains, this paper conducts both tensile and stress relaxation tests on PVDF materials. To describe the stress relaxation characteristics of these materials, the Prony series is utilized. In order to identify the parameters of the series, the paper employs the Levenberg-Marquardt method of nonlinear regression. A finite element model is established to verify the accuracy of the parameter identification method. Subsequently, the paper establishes a two-dimensional axisymmetric finite element model of the sealing system in the end fitting, while taking into account fluid pressure inside the pipeline using a pressure penetration method. The impact of stress relaxation on the sealing performance is then discussed. Finally, the paper alters the coefficients of the Prony series to explore their significance on the sealing performance of the sealing system.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 3","pages":"Pages 308-321"},"PeriodicalIF":13.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135761207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-06-01DOI: 10.1016/j.joes.2023.12.002
Kan Huang , Xiaoni Wu , Zhiliang Lin
Local scour is a phenomenon that occurs around water-blocking structures such as bridge piers, pile foundations, and pipelines, which threatens seriously the safety of structures. The laboratory test based on wave and flow tanks is an effective way investigating the local scour around piles. The measurement of scour depth and topography is an important basis for this type of experimental analysis, which can help the researchers to perform a quantitative analysis on the scour mechanism. The conventional measurement methods in scouring experiments have limitations in terms of operational efficiency, measurement range, and cost. Therefore, an advanced experimental measurement technique based on the RGB-D sensor and the 3D reconstruction algorithm was proposed in this work to provide the full topography information around target zone after scour. Experiments applying this 3D reconstruction method were conducted for the practical scour tests. The impact of water on the application of this technique was discussed as well. The results showed that the new technique has good accuracy in scour topography description and scour depth measurement. This work provides a new measure technique for laboratory scour tests. The proposed method has a broad application prospect in measurements for such experimental scenes.
{"title":"An advanced laboratorial measurement technique of scour topography based on the fusion method for 3D reconstruction","authors":"Kan Huang , Xiaoni Wu , Zhiliang Lin","doi":"10.1016/j.joes.2023.12.002","DOIUrl":"10.1016/j.joes.2023.12.002","url":null,"abstract":"<div><div>Local scour is a phenomenon that occurs around water-blocking structures such as bridge piers, pile foundations, and pipelines, which threatens seriously the safety of structures. The laboratory test based on wave and flow tanks is an effective way investigating the local scour around piles. The measurement of scour depth and topography is an important basis for this type of experimental analysis, which can help the researchers to perform a quantitative analysis on the scour mechanism. The conventional measurement methods in scouring experiments have limitations in terms of operational efficiency, measurement range, and cost. Therefore, an advanced experimental measurement technique based on the RGB-D sensor and the 3D reconstruction algorithm was proposed in this work to provide the full topography information around target zone after scour. Experiments applying this 3D reconstruction method were conducted for the practical scour tests. The impact of water on the application of this technique was discussed as well. The results showed that the new technique has good accuracy in scour topography description and scour depth measurement. This work provides a new measure technique for laboratory scour tests. The proposed method has a broad application prospect in measurements for such experimental scenes.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 3","pages":"Pages 322-329"},"PeriodicalIF":13.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138985988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-06-01DOI: 10.1016/j.joes.2024.04.001
Bingjing Lu , Jingjing Zuo , Mohammad Shahhosseini , Hui Wang , Haichao Liu , Minxi Zhang , Guoliang Yu
Local scour threatens the safety of marine structures, necessitating the precise prediction of scour evolution around these structures. A visually oriented deep learning model, called Disentangled Physics-constrained Prediction (DPP), was proposed in this study to predict scour evolution at monopiles reliably. It integrates scouring physics with advanced video prediction techniques through a two-branch architecture. The Physics-constrained Recurrent Module (PRModule) branch leverages Recurrent Neural Networks (RNNs) for temporal differentiation, ensuring accurate prediction of scouring-related physical information. Meanwhile, the Convolutional Long-Short-Term Memory (ConvLSTM) branch captures spatial and temporal dynamics in scouring videos, focusing on the prediction of residual features. DPP outperformed three baseline models in predicting the scour evolution at monopiles. Across three scouring scenarios, DPP achieved a 14.2% decrease in Root Mean Squared Error, a 14.7% reduction in Mean Absolute Error, and an 8.1% increase in Structural Similarity on average, compared to the best-performing baseline model. The predicted scouring frames are found to agree well with the true frames, demonstrating DPP's potential as a valuable tool to protect marine infrastructures.
{"title":"Visual deep learning with physics constraints for local scour evolution prediction at monopiles","authors":"Bingjing Lu , Jingjing Zuo , Mohammad Shahhosseini , Hui Wang , Haichao Liu , Minxi Zhang , Guoliang Yu","doi":"10.1016/j.joes.2024.04.001","DOIUrl":"10.1016/j.joes.2024.04.001","url":null,"abstract":"<div><div>Local scour threatens the safety of marine structures, necessitating the precise prediction of scour evolution around these structures. A visually oriented deep learning model, called Disentangled Physics-constrained Prediction (DPP), was proposed in this study to predict scour evolution at monopiles reliably. It integrates scouring physics with advanced video prediction techniques through a two-branch architecture. The Physics-constrained Recurrent Module (PRModule) branch leverages Recurrent Neural Networks (RNNs) for temporal differentiation, ensuring accurate prediction of scouring-related physical information. Meanwhile, the Convolutional Long-Short-Term Memory (ConvLSTM) branch captures spatial and temporal dynamics in scouring videos, focusing on the prediction of residual features. DPP outperformed three baseline models in predicting the scour evolution at monopiles. Across three scouring scenarios, DPP achieved a 14.2% decrease in Root Mean Squared Error, a 14.7% reduction in Mean Absolute Error, and an 8.1% increase in Structural Similarity on average, compared to the best-performing baseline model. The predicted scouring frames are found to agree well with the true frames, demonstrating DPP's potential as a valuable tool to protect marine infrastructures.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 3","pages":"Pages 342-352"},"PeriodicalIF":13.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140779499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Local scour at a pile or pier in current or wave environments threats the safety of the upper structure all over the world. The application of a net-like matt as a scour protection cover at the pile or pier was proposed. The matt weakens and diffuses the flow in the local scour pit and thus reduces local scour while enhances sediment deposition. Numerical simulations were carried out to investigate the flow at the pile covered by the matt. The simulation results were used to optimize the thickness (2.6) and opening size () of the matt. It was found that the matt significantly reduced the local velocity and dissipated the vortex at the pile, substantially reduced the extent of local scour. The smaller the opening size of the matt, the more effective was the flow diffusion at the bed, and smaller bed shear stress was observed at the pile. For the flow conditions considered in this study, a matt with a relative thickness of T = 7.7 and relative opening size of S = 7.7 could be effective in scour protection.
{"title":"Numerical study of the flow at a vertical pile with net-like scour protection matt","authors":"Minxi Zhang , Hanyan Zhao , Dongliang Zhao , Shaolin Yue , Huan Zhou , Xudong Zhao , Carlo Gualtieri , Guoliang Yu","doi":"10.1016/j.joes.2023.06.002","DOIUrl":"10.1016/j.joes.2023.06.002","url":null,"abstract":"<div><div>Local scour at a pile or pier in current or wave environments threats the safety of the upper structure all over the world. The application of a net-like matt as a scour protection cover at the pile or pier was proposed. The matt weakens and diffuses the flow in the local scour pit and thus reduces local scour while enhances sediment deposition. Numerical simulations were carried out to investigate the flow at the pile covered by the matt. The simulation results were used to optimize the thickness <span><math><msub><mi>d</mi><mi>t</mi></msub></math></span> (2.6<span><math><mrow><msub><mi>d</mi><mn>95</mn></msub><mo>∼</mo><mn>17.9</mn><msub><mi>d</mi><mn>95</mn></msub></mrow></math></span>) and opening size <span><math><msub><mi>d</mi><mi>n</mi></msub></math></span> (<span><math><mrow><mn>7.7</mn><msub><mi>d</mi><mn>95</mn></msub><mo>∼</mo><mn>28.2</mn><msub><mi>d</mi><mn>95</mn></msub></mrow></math></span>) of the matt. It was found that the matt significantly reduced the local velocity and dissipated the vortex at the pile, substantially reduced the extent of local scour. The smaller the opening size of the matt, the more effective was the flow diffusion at the bed, and smaller bed shear stress was observed at the pile. For the flow conditions considered in this study, a matt with a relative thickness of <em>T</em> = 7.7 and relative opening size of <em>S</em> = 7.7 could be effective in scour protection.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 3","pages":"Pages 295-307"},"PeriodicalIF":13.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43087195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A large eddy simulation (LES) is conducted to investigate the distribution of turbulence kinetic energy (TKE) under a plunging solitary wave over a 1:15 slope. This study provides a novel contribution to the field by examining the roles of resolved and sub-grid scale TKE in plunging solitary waves at the different stages of wave breaking. Furthermore, comparing the performances of two sub-grid scale (SGS) models in simulating the distribution of TKE was carried out to identify their performances. The separate investigation of these components in the context of wave breaking and recognizing the importance of an appropriate sub-grid scale model to consider the effects of small-scale eddies provide a significant advancement in understanding coastal morphological changes and nearshore sediment transport. Both the zero-equation and one-equation SGS models demonstrated acceptable performance in simulating water surface and kinematic properties. The one-equation SGS model, however, provided more accurate results on TKE transport during the breaking process and as the wave approaches its collapsing point. The study’s results reveal that an SGS model’s inability to simulate TKE transport (such as in the zero equation model) leads to inaccurate simulations of the TKE level and breaking location in the breaking zone. Additionally, the results of the one-equation model demonstrated that the maximum horizontal fluid velocity around the wavefront surface is a better predictor of breaking wave onset than the horizontal fluid velocity at the wave crest.
{"title":"Large eddy simulation of plunging solitary wave: Understanding the breaking and turbulent mechanisms along shoaling region","authors":"Abbasali Rahmani , Alireza Keramat , Jinghua Wang , Huan-Feng Duan","doi":"10.1016/j.joes.2023.07.008","DOIUrl":"10.1016/j.joes.2023.07.008","url":null,"abstract":"<div><div>A large eddy simulation (LES) is conducted to investigate the distribution of turbulence kinetic energy (TKE) under a plunging solitary wave over a 1:15 slope. This study provides a novel contribution to the field by examining the roles of resolved and sub-grid scale TKE in plunging solitary waves at the different stages of wave breaking. Furthermore, comparing the performances of two sub-grid scale (SGS) models in simulating the distribution of TKE was carried out to identify their performances. The separate investigation of these components in the context of wave breaking and recognizing the importance of an appropriate sub-grid scale model to consider the effects of small-scale eddies provide a significant advancement in understanding coastal morphological changes and nearshore sediment transport. Both the zero-equation and one-equation SGS models demonstrated acceptable performance in simulating water surface and kinematic properties. The one-equation SGS model, however, provided more accurate results on TKE transport during the breaking process and as the wave approaches its collapsing point. The study’s results reveal that an SGS model’s inability to simulate TKE transport (such as in the zero equation model) leads to inaccurate simulations of the TKE level and breaking location in the breaking zone. Additionally, the results of the one-equation model demonstrated that the maximum horizontal fluid velocity around the wavefront surface is a better predictor of breaking wave onset than the horizontal fluid velocity at the wave crest.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 3","pages":"Pages 366-378"},"PeriodicalIF":13.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47549299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-06-01DOI: 10.1016/j.joes.2024.02.001
J.A. Bocanegra , D. Borelli , T. Gaggero , R. Picó , G. Tani
The noise radiated by ship propellers can be studied by analyzing scaled models in a cavitation tunnel. However, transferring the measurements made in the enclosed space of the tunnel to the expected values in a full-scale propeller (in a free field) presents a challenge for noise measurements. An acoustic characterization of the DITEN cavitation tunnel, including a study of normal modes and acoustic response to harmonic sources, is presented to understand the primary acoustic behaviour of the enclosure and its propagation characteristics. A three-dimensional numerical model was developed to simulate the DITEN Genoa University cavitation tunnel and evaluate the influence of elements such as a dynamometer, fins, impeller, and source position on the acoustic response of the tunnel. The study showed the influence of the mentioned elements on the acoustic response of the tunnel, and the numerical predictions were validated by comparing them with the experimental campaign in the low-mid frequency range. The study provides valuable insights into the behaviour of sound waves in a cavitation tunnel and the influence of various factors, which can help design and optimize cavitation tunnels and related experiments.
{"title":"Acoustic characterization of a cavitation tunnel for ship propeller noise studies","authors":"J.A. Bocanegra , D. Borelli , T. Gaggero , R. Picó , G. Tani","doi":"10.1016/j.joes.2024.02.001","DOIUrl":"10.1016/j.joes.2024.02.001","url":null,"abstract":"<div><div>The noise radiated by ship propellers can be studied by analyzing scaled models in a cavitation tunnel. However, transferring the measurements made in the enclosed space of the tunnel to the expected values in a full-scale propeller (in a free field) presents a challenge for noise measurements. An acoustic characterization of the DITEN cavitation tunnel, including a study of normal modes and acoustic response to harmonic sources, is presented to understand the primary acoustic behaviour of the enclosure and its propagation characteristics. A three-dimensional numerical model was developed to simulate the DITEN Genoa University cavitation tunnel and evaluate the influence of elements such as a dynamometer, fins, impeller, and source position on the acoustic response of the tunnel. The study showed the influence of the mentioned elements on the acoustic response of the tunnel, and the numerical predictions were validated by comparing them with the experimental campaign in the low-mid frequency range. The study provides valuable insights into the behaviour of sound waves in a cavitation tunnel and the influence of various factors, which can help design and optimize cavitation tunnels and related experiments.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 3","pages":"Pages 330-341"},"PeriodicalIF":13.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139892367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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