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 : 2025-06-01Epub Date: 2024-02-07DOI: 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}
Pub Date : 2025-06-01Epub Date: 2024-06-07DOI: 10.1016/j.joes.2024.05.002
Rongze Wang , Quan Shi , Xinliang Tian , Xiaoxian Guo , Xin Li , Jianmin Yang
The twin-barge float-over technique, incorporating a dynamic positioning (DP) system, has been increasingly utilized to enhance the installation capacity and efficiency of offshore platforms. But the DP system is not fully considered during the design stage at present. This study investigates the dynamic responses of a twin-barge float-over system integrating flexible connections and DP system. A numerical model is developed and combined with model-scale experiments to analyze the characteristics of the system. The findings reveal the significant influence of the DP system on the coupled system, leading to harsh oscillations in the roll and heave directions. To effectively address this oscillation, a method with eigenmodes analysis and filter adjusting is proposed. The robustness of this method is verified through sensitivity analysis, and further investigation is conducted to analyze the motion response characteristics of the coupled system under varying environmental conditions. The findings and the proposed method in this paper are also applicable to various multi-vessel cooperative transportation scenarios.
{"title":"Dynamic responses of a twin-DP-barge float-over installation system with flexible connections","authors":"Rongze Wang , Quan Shi , Xinliang Tian , Xiaoxian Guo , Xin Li , Jianmin Yang","doi":"10.1016/j.joes.2024.05.002","DOIUrl":"10.1016/j.joes.2024.05.002","url":null,"abstract":"<div><div>The twin-barge float-over technique, incorporating a dynamic positioning (DP) system, has been increasingly utilized to enhance the installation capacity and efficiency of offshore platforms. But the DP system is not fully considered during the design stage at present. This study investigates the dynamic responses of a twin-barge float-over system integrating flexible connections and DP system. A numerical model is developed and combined with model-scale experiments to analyze the characteristics of the system. The findings reveal the significant influence of the DP system on the coupled system, leading to harsh oscillations in the roll and heave directions. To effectively address this oscillation, a method with eigenmodes analysis and filter adjusting is proposed. The robustness of this method is verified through sensitivity analysis, and further investigation is conducted to analyze the motion response characteristics of the coupled system under varying environmental conditions. The findings and the proposed method in this paper are also applicable to various multi-vessel cooperative transportation scenarios.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 3","pages":"Pages 353-365"},"PeriodicalIF":13.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141395683","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 : 2025-04-01Epub Date: 2024-05-14DOI: 10.1016/j.joes.2024.05.001
Fabian Thies, Jonas W. Ringsberg
Accurately predicting the power saving from wind-assisted ship propulsion is one of the most discussed topics in alternative and complementary propulsion methods. Aero- and hydrodynamic interactions between the sails and the ship increase the difficulty of modelling the propulsion contribution theoretically, but the sensibility of sail performance on the wind conditions increases the demands on measurement accuracy if the performance is to be measured in sea trials. This paper analyses and compares the uncertainties of sea trial tests and model predictions by means of parameter variation and Monte Carlo simulations. The results show that sea trials have an uncertainty of 23 %, well above 100 % of the measured savings, if performed using normal onboard equipment. Model uncertainties were found to be between 6 % and 17 % of the predicted savings.
{"title":"Sea trials vs prediction by numerical models—Uncertainties in the measurements and prediction of WASP performance","authors":"Fabian Thies, Jonas W. Ringsberg","doi":"10.1016/j.joes.2024.05.001","DOIUrl":"10.1016/j.joes.2024.05.001","url":null,"abstract":"<div><div>Accurately predicting the power saving from wind-assisted ship propulsion is one of the most discussed topics in alternative and complementary propulsion methods. Aero- and hydrodynamic interactions between the sails and the ship increase the difficulty of modelling the propulsion contribution theoretically, but the sensibility of sail performance on the wind conditions increases the demands on measurement accuracy if the performance is to be measured in sea trials. This paper analyses and compares the uncertainties of sea trial tests and model predictions by means of parameter variation and Monte Carlo simulations. The results show that sea trials have an uncertainty of 23 %, well above 100 % of the measured savings, if performed using normal onboard equipment. Model uncertainties were found to be between 6 % and 17 % of the predicted savings.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 2","pages":"Pages 239-245"},"PeriodicalIF":13.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141032096","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 : 2025-04-01Epub Date: 2022-06-24DOI: 10.1016/j.joes.2022.06.036
Usman Younas , Hadi Rezazadeh , Jingli Ren
In this manuscript, we discuss the dynamical behavior of Chen-Lee-Liu (CLL) equation in birefringent fibers which is modeled by two-component nonlinear Schrodinger equation (NLSE) without four-wave mixing effect. In optical fibers and other wave-guide mediums this system models the propagation of soliton flow using group velocity dispersion (GVD) and self-steeping coefficients. In the realms of maritime transport, motion, and energy, the dynamics of deep-sea waves is one of oceanography’s greatest challenges. A mathematical model of the dynamics of solitary waves in the deep ocean under a two-layer stratification yields the NLSE, and resultantly, the interaction between the two can be described by a coupled NLSE. Using two recently developed integration tools, namely the generalized exponential rational function method (GERFM) and the new extended direct algebraic method (NEDAM), the various optical pulses in the forms of bright, dark, combined, and complex solitons are extracted. Moreover, the hyperbolic, exponential, and trigonometric function solutions are recovered. In addition, a comparison is made between our results and those that are well-known, and the study concludes that the solutions we’ve reached are novel. By choosing appropriate parameter values for numerical simulation and physical explanations, the significance of the results is demonstrated. The results of this paper can enhance the nonlinear dynamical behavior of a given system and demonstrate the suitability of the methodology employed. This research, in our opinion, will be beneficial to a wide variety of engineering model specialists.
{"title":"Dynamics of optical pulses in birefringent fibers without four-wave mixing effect via efficient computational techniques","authors":"Usman Younas , Hadi Rezazadeh , Jingli Ren","doi":"10.1016/j.joes.2022.06.036","DOIUrl":"10.1016/j.joes.2022.06.036","url":null,"abstract":"<div><div>In this manuscript, we discuss the dynamical behavior of Chen-Lee-Liu (CLL) equation in birefringent fibers which is modeled by two-component nonlinear Schrodinger equation (NLSE) without four-wave mixing effect. In optical fibers and other wave-guide mediums this system models the propagation of soliton flow using group velocity dispersion (GVD) and self-steeping coefficients. In the realms of maritime transport, motion, and energy, the dynamics of deep-sea waves is one of oceanography’s greatest challenges. A mathematical model of the dynamics of solitary waves in the deep ocean under a two-layer stratification yields the NLSE, and resultantly, the interaction between the two can be described by a coupled NLSE. Using two recently developed integration tools, namely the generalized exponential rational function method (GERFM) and the new extended direct algebraic method (NEDAM), the various optical pulses in the forms of bright, dark, combined, and complex solitons are extracted. Moreover, the hyperbolic, exponential, and trigonometric function solutions are recovered. In addition, a comparison is made between our results and those that are well-known, and the study concludes that the solutions we’ve reached are novel. By choosing appropriate parameter values for numerical simulation and physical explanations, the significance of the results is demonstrated. The results of this paper can enhance the nonlinear dynamical behavior of a given system and demonstrate the suitability of the methodology employed. This research, in our opinion, will be beneficial to a wide variety of engineering model specialists.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 2","pages":"Pages 181-196"},"PeriodicalIF":13.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41413443","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 : 2025-04-01Epub Date: 2024-01-19DOI: 10.1016/j.joes.2024.01.002
Isaac Slaughter , Jagir Laxmichand Charla , Martin Siderius , John Lipor
Maritime situational awareness tasks such as port management, collision avoidance, and search-and-rescue missions rely on accurate knowledge of vessel locations. The availability of historical vessel trajectory data through the Automatic Identification System (AIS) has enabled the development of prediction methods, with a recent focus on trajectory prediction via recurrent neural networks (RNNs) and other deep learning architectures. While these methods have shown promising performance benefits over kinematic and clustering-based models, comparing among RNN-based models remains difficult due to variations in evaluation datasets, region sizes, vessel types, and numerous other design choices. As a result, it is not clear whether recent methods based on highly-sophisticated network architectures are necessary to achieve strong prediction performance. In this work, we present a simple fusion-based RNN approach to vessel trajectory prediction that allows for easy incorporation of exogenous variables. We perform an extensive ablation study to measure the impact of various modeling choices, including preprocessing, loss functions, and the choice of features, as well as the first usage of surface current information in vessel trajectory prediction. We demonstrate that our approach achieves state-of-the-art performance on three large regions off the United States coast, obtaining an improvement of up to 0.88 km over competing methods when predicting three hours into the future. We conclude that our simple architecture can outperform more complicated architectures while incurring a lower memory cost. Further, we show that the choice of loss function and the inclusion of surface current information both have significant impact on prediction performance.
{"title":"Vessel trajectory prediction with recurrent neural networks: An evaluation of datasets, features, and architectures","authors":"Isaac Slaughter , Jagir Laxmichand Charla , Martin Siderius , John Lipor","doi":"10.1016/j.joes.2024.01.002","DOIUrl":"10.1016/j.joes.2024.01.002","url":null,"abstract":"<div><div>Maritime situational awareness tasks such as port management, collision avoidance, and search-and-rescue missions rely on accurate knowledge of vessel locations. The availability of historical vessel trajectory data through the Automatic Identification System (AIS) has enabled the development of prediction methods, with a recent focus on trajectory prediction via recurrent neural networks (RNNs) and other deep learning architectures. While these methods have shown promising performance benefits over kinematic and clustering-based models, comparing among RNN-based models remains difficult due to variations in evaluation datasets, region sizes, vessel types, and numerous other design choices. As a result, it is not clear whether recent methods based on highly-sophisticated network architectures are necessary to achieve strong prediction performance. In this work, we present a simple fusion-based RNN approach to vessel trajectory prediction that allows for easy incorporation of exogenous variables. We perform an extensive ablation study to measure the impact of various modeling choices, including preprocessing, loss functions, and the choice of features, as well as the first usage of surface current information in vessel trajectory prediction. We demonstrate that our approach achieves state-of-the-art performance on three large regions off the United States coast, obtaining an improvement of up to 0.88 km over competing methods when predicting three hours into the future. We conclude that our simple architecture can outperform more complicated architectures while incurring a lower memory cost. Further, we show that the choice of loss function and the inclusion of surface current information both have significant impact on prediction performance.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 2","pages":"Pages 229-238"},"PeriodicalIF":13.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139637147","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 : 2025-04-01Epub Date: 2023-10-13DOI: 10.1016/j.joes.2023.10.002
Deyu Li , Handi Wei , Longfei Xiao , Ruiwen Zhang , Yan Li
The spatial-temporal measurement of complex wave evolution is significant in studying wave-structure interactions. Current methods, such as that using wave probes, have shown limitations in measuring the wave evolution around structures in laboratories. In this study, an improved stereo imaging method is proposed for measuring the wave evolution around a fixed structure. Regular wave tests were conducted on a fixed surface-piercing square column in a wave flume to validate the reliability and accuracy of the proposed method. A flexible marker-net made of foam particles was arranged around the column to provide Lambertian features for the water surface. Two synchronized stereo imaging systems covered all the surrounding areas of the column and provided stereo pair sequences for wave evolution. Subsequently, image segmentation techniques were used to mask the low-confidence disparities in stereo matching, and finally, three-dimensional (3D) wave surfaces were reconstructed in the time sequence. The time histories of the wave elevations at particular locations were extracted and agreed well with the measurements of wave probes with an average bias of 2.4 %. Subsequently, the reconstructed 3D wave field was sliced, exhibiting the instantaneous profiles that agreed with the measurements of wave probes. Moreover, the wave run-up height ratios were consistent with those of a previous study, thereby verifying the method's accuracy from the perspective of spatial evolution. The results demonstrated that the proposed method was capable of precisely measuring the spatial-temporal evolution of the wave field around the square column and displayed potential for application in more studies on wave-structure interactions.
{"title":"Stereo vision-based measurement of wave evolution around square column in laboratory","authors":"Deyu Li , Handi Wei , Longfei Xiao , Ruiwen Zhang , Yan Li","doi":"10.1016/j.joes.2023.10.002","DOIUrl":"10.1016/j.joes.2023.10.002","url":null,"abstract":"<div><div>The spatial-temporal measurement of complex wave evolution is significant in studying wave-structure interactions. Current methods, such as that using wave probes, have shown limitations in measuring the wave evolution around structures in laboratories. In this study, an improved stereo imaging method is proposed for measuring the wave evolution around a fixed structure. Regular wave tests were conducted on a fixed surface-piercing square column in a wave flume to validate the reliability and accuracy of the proposed method. A flexible marker-net made of foam particles was arranged around the column to provide Lambertian features for the water surface. Two synchronized stereo imaging systems covered all the surrounding areas of the column and provided stereo pair sequences for wave evolution. Subsequently, image segmentation techniques were used to mask the low-confidence disparities in stereo matching, and finally, three-dimensional (3D) wave surfaces were reconstructed in the time sequence. The time histories of the wave elevations at particular locations were extracted and agreed well with the measurements of wave probes with an average bias of 2.4 %. Subsequently, the reconstructed 3D wave field was sliced, exhibiting the instantaneous profiles that agreed with the measurements of wave probes. Moreover, the wave run-up height ratios were consistent with those of a previous study, thereby verifying the method's accuracy from the perspective of spatial evolution. The results demonstrated that the proposed method was capable of precisely measuring the spatial-temporal evolution of the wave field around the square column and displayed potential for application in more studies on wave-structure interactions.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 2","pages":"Pages 281-294"},"PeriodicalIF":13.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135708005","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}
Inspired by ITTC 2021 (International Towing Tank Conference), this paper implements the Longitudinal Cut Method (LCM), a methodology to predict wave pattern resistance (Rwp), within Computational Fluid Dynamics (CFD) simulation to explore its mechanism and feasibility in predicting wave resistance (Rw). To accurately predict the free surface, a validation study, including the grid convergence index (GCI), wave profile, and wave pattern, is conducted for a Series 60 ship model. Next, Rwp is appropriately evaluated and compared with the experiment. The influence of the transverse wave component on the LCM analysis is also discussed. Furthermore, a comparison between the EFD (Experimental Fluid Dynamics) and CFD-based LCM is made through the analysis of the Wigley Catamaran, highlighting the advantages of the present approach. Finally, the limitations of the LCM theory are systematically discussed with the nonlinear bow wave analysis of a wall-sided ship model by introducing the local adaptive mesh refinement (LAMR) approach. For the fine hull form, LCM has been validated as a suitable methodology for directly predicting Rw and consequently the other primary resistance components (frictional resistance Rf and viscous pressure resistance Rpv) by one simulation. In contrast, due to energy dissipation of the non-negligible nonlinear local field wave component in the downstream wake region, Rw could be underestimated for the full hull form.
{"title":"Mechanism analysis and prediction of longitudinal cut wave pattern resistance based on CFD simulation","authors":"Xiaocong Wang, Renchuan Zhu, Dekang Xu, Hui Wang, Yue Gu","doi":"10.1016/j.joes.2023.07.001","DOIUrl":"10.1016/j.joes.2023.07.001","url":null,"abstract":"<div><div>Inspired by ITTC 2021 (International Towing Tank Conference), this paper implements the Longitudinal Cut Method (LCM), a methodology to predict wave pattern resistance (<em>R<sub>wp</sub></em>), within Computational Fluid Dynamics (CFD) simulation to explore its mechanism and feasibility in predicting wave resistance (<em>R<sub>w</sub></em>). To accurately predict the free surface, a validation study, including the grid convergence index (<em>GCI</em>), wave profile, and wave pattern, is conducted for a Series 60 ship model. Next, <em>R<sub>wp</sub></em> is appropriately evaluated and compared with the experiment. The influence of the transverse wave component on the LCM analysis is also discussed. Furthermore, a comparison between the EFD (Experimental Fluid Dynamics) and CFD-based LCM is made through the analysis of the Wigley Catamaran, highlighting the advantages of the present approach. Finally, the limitations of the LCM theory are systematically discussed with the nonlinear bow wave analysis of a wall-sided ship model by introducing the local adaptive mesh refinement (LAMR) approach. For the fine hull form, LCM has been validated as a suitable methodology for directly predicting <em>R<sub>w</sub></em> and consequently the other primary resistance components (frictional resistance <em>R<sub>f</sub></em> and viscous pressure resistance <em>R<sub>pv</sub></em>) by one simulation. In contrast, due to energy dissipation of the non-negligible nonlinear local field wave component in the downstream wake region, <em>R<sub>w</sub></em> could be underestimated for the full hull form.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 2","pages":"Pages 258-273"},"PeriodicalIF":13.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48516165","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 : 2025-04-01Epub Date: 2022-05-31DOI: 10.1016/j.joes.2022.05.035
Noor Idora Mohd Sukarnoor , Lee Kee Quen , Aminudin Abu , Kang Hooi Siang , Noriyuki Kuwano , Safari Mat Desa
The flow interference of multiple cylinders subjected to vortex-induced vibration (VIV) is a complex response that is not fully understood. This paper investigates the fluid-dynamic behaviour of elastically mounted rigid cylinders where both cylinders were free to oscillate in the cross-flow direction. The cylinders were subjected to uniform water flow at various separation distances of 3.5, 4.0, and 4.5D (D is the diameter of the cylinder) in a tandem arrangement. Based on the observation, the interference between the cylinders and the unsteady wake from the leading cylinder caused a continuous vibration with no lower branch in amplitude response. While as found in the cases of the single cylinder, there was a lower branch in amplitude response. The results also revealed that the cylinders experienced the VIV and wake-induced vibration (WIV) at each separation distance. Moreover, the leading cylinder oscillated at a larger amplitude at a separation distance of 3.5D, indicating a critical distance for cylinders in the tandem arrangement due to the existence of a bistable regime. Hence, it is reasonable to conclude that the flow interference between the leading and trailing cylinders significantly impacts the cylinders’ dynamic behaviour.
{"title":"An investigation of the dynamic behaviour of two rigid cylinders in a tandem arrangement under vortex-induced vibration","authors":"Noor Idora Mohd Sukarnoor , Lee Kee Quen , Aminudin Abu , Kang Hooi Siang , Noriyuki Kuwano , Safari Mat Desa","doi":"10.1016/j.joes.2022.05.035","DOIUrl":"10.1016/j.joes.2022.05.035","url":null,"abstract":"<div><div>The flow interference of multiple cylinders subjected to vortex-induced vibration (VIV) is a complex response that is not fully understood. This paper investigates the fluid-dynamic behaviour of elastically mounted rigid cylinders where both cylinders were free to oscillate in the cross-flow direction. The cylinders were subjected to uniform water flow at various separation distances of 3.5, 4.0, and 4.5<em>D</em> (<em>D</em> is the diameter of the cylinder) in a tandem arrangement. Based on the observation, the interference between the cylinders and the unsteady wake from the leading cylinder caused a continuous vibration with no lower branch in amplitude response. While as found in the cases of the single cylinder, there was a lower branch in amplitude response. The results also revealed that the cylinders experienced the VIV and wake-induced vibration (WIV) at each separation distance. Moreover, the leading cylinder oscillated at a larger amplitude at a separation distance of 3.5<em>D</em>, indicating a critical distance for cylinders in the tandem arrangement due to the existence of a bistable regime. Hence, it is reasonable to conclude that the flow interference between the leading and trailing cylinders significantly impacts the cylinders’ dynamic behaviour.</div></div>","PeriodicalId":48514,"journal":{"name":"Journal of Ocean Engineering and Science","volume":"10 2","pages":"Pages 246-257"},"PeriodicalIF":13.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42906513","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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