Abstract Floating offshore wind turbines (FOWTs) are an opportunity for floating production storage and offloading units (FPSOs) to reduce emissions. To avoid long connecting power cables with long transmission distances between a FOWT and an FPSO, the novel concept of a suspended power cable in a large water depth of 1000 m is investigated in this study. The power cable is kept floating between the sea surface and the seabed without touching either of them. A catenary configuration and two configurations with subsea buoys attached at different locations along the cable are investigated. The OC3-Hywind 5 MW reference FOWT is set up with a deepwater mooring system, and a spread-moored FPSO is modeled with characteristics similar to existing FPSOs. Steady-state and dynamic simulations are carried out in the numerical software OrcaFlex. The different configurations are first evaluated in steady-state analyses. The largest tensions are observed for the catenary configuration, whereas it shows the lowest horizontal cable excursions. Buoys attached along the center section of the cable lift it into regions with strong currents. This results in a large horizontal excursion of the cable and large tensions. The suspended configuration with buoys attached evenly over the cable results in significantly lower tensions than the other two configurations. It is studied further with dynamic analyses. The tensions at the floater hang-offs increase by a maximum of 24% compared to steady-state results indicating that dynamic analysis is crucial for the design of suspended cable configurations.
{"title":"Numerical Investigations on Suspended Power Cable Configurations for Floating Offshore Wind Turbines in Deep Water Powering an FPSO","authors":"Anja Schnepf, Aymeric Devulder, Øyvind Johnsen, Muk Chen Ong, Carlos Lopez-Pavon","doi":"10.1115/1.4057006","DOIUrl":"https://doi.org/10.1115/1.4057006","url":null,"abstract":"Abstract Floating offshore wind turbines (FOWTs) are an opportunity for floating production storage and offloading units (FPSOs) to reduce emissions. To avoid long connecting power cables with long transmission distances between a FOWT and an FPSO, the novel concept of a suspended power cable in a large water depth of 1000 m is investigated in this study. The power cable is kept floating between the sea surface and the seabed without touching either of them. A catenary configuration and two configurations with subsea buoys attached at different locations along the cable are investigated. The OC3-Hywind 5 MW reference FOWT is set up with a deepwater mooring system, and a spread-moored FPSO is modeled with characteristics similar to existing FPSOs. Steady-state and dynamic simulations are carried out in the numerical software OrcaFlex. The different configurations are first evaluated in steady-state analyses. The largest tensions are observed for the catenary configuration, whereas it shows the lowest horizontal cable excursions. Buoys attached along the center section of the cable lift it into regions with strong currents. This results in a large horizontal excursion of the cable and large tensions. The suspended configuration with buoys attached evenly over the cable results in significantly lower tensions than the other two configurations. It is studied further with dynamic analyses. The tensions at the floater hang-offs increase by a maximum of 24% compared to steady-state results indicating that dynamic analysis is crucial for the design of suspended cable configurations.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134964734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Venkateswarlu, S. Rayudu, Dhanunjaya E, Vijay K G
The comprehensive usage of an array of natural or artificial semi-circular breakwaters (SCB) as supporting structures to secure the floating/fixed structures are received increasingly more consideration in recent years. The performance characteristics of bottom-fixed SCB in the presence of a floating dock are investigated under the framework of linear wave theory. The edge conditions such as continuity of velocity and pressure along the SCB and zero flow condition near rigid surfaces are adopted. The multi-domain boundary element method (MBEM) is used to examine the wave attenuation performance of the whole breakwater system in two dimensions. The correctness of the present study's numerical results is confirmed by performing the comparative study with the readily available experimental and analytical results reported by various researchers. The reflection, transmission, energy loss coefficients, and fluid force experienced by floating dock are examined as a function of incident wave properties and breakwater physical properties. The Bragg resonant reflection and performance comparison with other shapes are also studied. The study results strongly suggest that the damage of floating structures and leeward locales due to incident wave stroke is minimized with the introduction of porosity for SCB located on the seabed by dissipating the wave energy. A pair of bottom fixed SCB having 10% - 20% breakwater porosity placed far away from the dock is identified as the optimal choice to reduce the fluid force experienced by the dock and wave transmission coefficient.
{"title":"Wave Action Analysis of Multiple Bottom Fixed Semi-Circular Breakwaters in the Presence of a Floating Dock","authors":"V. Venkateswarlu, S. Rayudu, Dhanunjaya E, Vijay K G","doi":"10.1115/1.4062114","DOIUrl":"https://doi.org/10.1115/1.4062114","url":null,"abstract":"\u0000 The comprehensive usage of an array of natural or artificial semi-circular breakwaters (SCB) as supporting structures to secure the floating/fixed structures are received increasingly more consideration in recent years. The performance characteristics of bottom-fixed SCB in the presence of a floating dock are investigated under the framework of linear wave theory. The edge conditions such as continuity of velocity and pressure along the SCB and zero flow condition near rigid surfaces are adopted. The multi-domain boundary element method (MBEM) is used to examine the wave attenuation performance of the whole breakwater system in two dimensions. The correctness of the present study's numerical results is confirmed by performing the comparative study with the readily available experimental and analytical results reported by various researchers. The reflection, transmission, energy loss coefficients, and fluid force experienced by floating dock are examined as a function of incident wave properties and breakwater physical properties. The Bragg resonant reflection and performance comparison with other shapes are also studied. The study results strongly suggest that the damage of floating structures and leeward locales due to incident wave stroke is minimized with the introduction of porosity for SCB located on the seabed by dissipating the wave energy. A pair of bottom fixed SCB having 10% - 20% breakwater porosity placed far away from the dock is identified as the optimal choice to reduce the fluid force experienced by the dock and wave transmission coefficient.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48845048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zongyu Jiang, Fang Li, T. Mikkola, P. Kujala, S. Hirdaris
For ships navigating in ice floe fields, ship-ice-wave interactions may affect ship performance and ice impact forces. This is because the added mass and hydrodynamic damping may influence hydromechanics and associated ship-ice interactions. This paper presents an approach to evaluate the cross-coupling added mass and hydrodynamic damping between a passing ship and a free-floating small/medium size ice floe based on the Boundary Element Method (BEM). The influences of added mass and hydrodynamic damping are explored for different wave frequencies and headings. Preliminary results are presented for a regular waves scenario whereby a tanker progressing at low speed is passing by a free-floating ice floe modelled as a round disk in close proximity. Radiation and diffraction potentials of the interacting floating bodies are linearly superimposed to reflect the influence of hydromechanical coupling on responses. Parametric analysis of Response Amplitude Operators (RAOs) indicates that the cross-coupling terms of added mass and hydrodynamic damping are of the same order of magnitude as those of the ice floe but smaller by one or two orders of magnitude than those of the ship. It is concluded that whereas the influence of hydrodynamic interactions primarily influences the motions of the ice floe, hydrodynamic interactions are significant attributes of the ship-ice system dynamics.
{"title":"A boundary element method for the prediction of hydrodynamic ship - ice -wave interactions in regular waves","authors":"Zongyu Jiang, Fang Li, T. Mikkola, P. Kujala, S. Hirdaris","doi":"10.1115/1.4062094","DOIUrl":"https://doi.org/10.1115/1.4062094","url":null,"abstract":"\u0000 For ships navigating in ice floe fields, ship-ice-wave interactions may affect ship performance and ice impact forces. This is because the added mass and hydrodynamic damping may influence hydromechanics and associated ship-ice interactions. This paper presents an approach to evaluate the cross-coupling added mass and hydrodynamic damping between a passing ship and a free-floating small/medium size ice floe based on the Boundary Element Method (BEM). The influences of added mass and hydrodynamic damping are explored for different wave frequencies and headings. Preliminary results are presented for a regular waves scenario whereby a tanker progressing at low speed is passing by a free-floating ice floe modelled as a round disk in close proximity. Radiation and diffraction potentials of the interacting floating bodies are linearly superimposed to reflect the influence of hydromechanical coupling on responses. Parametric analysis of Response Amplitude Operators (RAOs) indicates that the cross-coupling terms of added mass and hydrodynamic damping are of the same order of magnitude as those of the ice floe but smaller by one or two orders of magnitude than those of the ship. It is concluded that whereas the influence of hydrodynamic interactions primarily influences the motions of the ice floe, hydrodynamic interactions are significant attributes of the ship-ice system dynamics.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48635520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Song Ji, Heng Huang, Xu-jun Chen, Jun-yi Liu, Xi Chen
Floating bodies are widely used in the field of offshore engineering. Existing studies show that the motion responses of a floating body in waves will change with the internal water in the cabins, and it is essential to analyze its hydrodynamic performance under various potential operating conditions. However, most of the research only considers the interaction between the floating body and the internal water in the upright position, and there has been little research on the inclined floating body caused by water partially filled in the broadside. In this study, a floating body with a plurality of longitudinal and transverse cabins was designed. The regular wave model test was carried out in a wave basin, and the numerical results were compared with the experimental results, which verified the accuracy of the model. The effects of wave direction, wave frequency, water filling depth and cabin division on the motion responses of the floating body are analyzed. The results show that the water inside the cabins has a significant impact on the roll motion. With the increase of the water filling depth, the natural frequency of the roll motion decreases. Special attention should be paid to the impact on the wave direction and cabin division on the partially water-filled inclined floating body.
{"title":"Numerical and experimental analysis of a partially water-filled inclined floating body","authors":"Song Ji, Heng Huang, Xu-jun Chen, Jun-yi Liu, Xi Chen","doi":"10.1115/1.4062095","DOIUrl":"https://doi.org/10.1115/1.4062095","url":null,"abstract":"\u0000 Floating bodies are widely used in the field of offshore engineering. Existing studies show that the motion responses of a floating body in waves will change with the internal water in the cabins, and it is essential to analyze its hydrodynamic performance under various potential operating conditions. However, most of the research only considers the interaction between the floating body and the internal water in the upright position, and there has been little research on the inclined floating body caused by water partially filled in the broadside. In this study, a floating body with a plurality of longitudinal and transverse cabins was designed. The regular wave model test was carried out in a wave basin, and the numerical results were compared with the experimental results, which verified the accuracy of the model. The effects of wave direction, wave frequency, water filling depth and cabin division on the motion responses of the floating body are analyzed. The results show that the water inside the cabins has a significant impact on the roll motion. With the increase of the water filling depth, the natural frequency of the roll motion decreases. Special attention should be paid to the impact on the wave direction and cabin division on the partially water-filled inclined floating body.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48113749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Since 1987, the ASME Journal of Offshore Mechanics and Arctic Engineering has been a dependable source for the dissemination of the studies of researchers, practitioners, and interested parties working in the ocean, offshore, arctic, and related fields. It is where one can read and learn from peer-reviewed research on all aspects of analysis, design, and technology development in these fields. The journal’s goal remains one of showcasing fundamental research and development studies; it has also featured review articles and perspectives on well-established as well as emerging topics.As I did in a recent editorial that appeared in the April 2022 issue of this journal [1] (and which cited three earlier similar editorials that appeared in June 2019, August 2020, and October 2021), I am seeking to once again highlight the efforts and dedication of an international team of Associate Editors, focusing on profiles of two of them at a time. It is this team that helps keep the journal vibrant, relevant, and timely in allowing the exchange of theoretical and practical developments in the ocean, offshore, and arctic engineering arena.Today, the journal has 38 Associate Editors who cover the breadth of areas in offshore mechanics and arctic engineering; they represent 14 countries, namely, Australia, Canada, China, Denmark, Finland, Germany, India, Italy, Japan, Mexico, Norway, Singapore, the United Kingdom, and the United States. With support from hard-working reviewers, these dedicated Associate Editors help this journal release six issues each year.I am truly delighted to continue this series of editorials profiling, each time, two Associate Editors and highlighting their expertise areas and accomplishments. I encourage you to learn about previously profiled Associate Editors [1]. In this issue, I present to you two Associate Editors—Dr. Madjid Karimirad, Associate Professor of Marine and Coastal Engineering at Queen’s University, Belfast, United Kingdom, and Dr. Xinshu Zhang, Professor of Naval Architecture and Ocean Engineering at Shanghai Jiao Tong University, China.Dr. Madjid Karimirad (Fig. 1) is an associate professor (Senior Lecturer) in marine and coastal engineering at Queen’s University Belfast (QUB) in the United Kingdom. Before he joined QUB in 2017, he was a Research Scientist at MARINTEK (Norwegian Marine Technology Research Institute) and SINTEF Ocean, Norway. He has more than 15 years of research experience dealing with marine structures and offshore technology. His background in both academia and industry is strong; he has worked as a research scientist and as a post-doctoral fellow and Ph.D. researcher in offshore technology, prior to his current appointment.Dr. Karimirad earned his Ph.D. in March 2011 in Marine Structures from the Norwegian University of Science and Technology (NTNU). He was employed previously at CeSOS (Centre for Ships and Ocean Structures), a Centre of Excellence in Norway. His post-doctoral research at CeSOS was part
自1987年以来，ASME海洋力学与北极工程杂志一直是海洋、近海、北极及相关领域的研究人员、实践者和感兴趣的各方研究成果传播的可靠来源。在这里，人们可以阅读和学习这些领域的分析、设计和技术开发的所有方面的同行评审研究。该杂志的目标仍然是展示基础研究和发展研究;它也有特色的评论文章和观点对既定的以及新兴的主题。正如我在《b[1]》杂志2022年4月号最近发表的一篇社论中所做的那样(文中引用了2019年6月、2020年8月和2021年10月发表的三篇类似的社论)，我试图再次强调一个国际副编辑团队的努力和奉献精神，一次关注两位副编辑的简介。正是这个团队帮助杂志保持活力、相关性，并及时交流海洋、近海和北极工程领域的理论和实践发展。今天，该杂志有38位副编辑，他们涵盖了海洋力学和北极工程的广泛领域;他们代表了14个国家，分别是澳大利亚、加拿大、中国、丹麦、芬兰、德国、印度、意大利、日本、墨西哥、挪威、新加坡、英国和美国。在辛勤工作的审稿人的支持下，这些专职的副编辑帮助该杂志每年出版六期。我真的很高兴能继续这一系列的社论，每次都介绍两位副主编，并强调他们的专业领域和成就。我鼓励您了解之前介绍的副编辑[1]。本期，我向大家介绍两位副主编。英国贝尔法斯特女王大学海洋与海岸工程副教授Madjid Karimirad，中国上海交通大学船舶与海洋工程教授Xinshu Zhang博士。Madjid Karimirad(图1)是英国贝尔法斯特女王大学(Queen’s University Belfast, QUB)海洋与海岸工程副教授(高级讲师)。在2017年加入QUB之前，他是MARINTEK(挪威海洋技术研究所)和挪威SINTEF海洋的研究科学家。他在海洋结构和海上技术方面有超过15年的研究经验。他在学术界和工业界都有很强的背景;在担任目前的职位之前，他曾担任研究科学家、博士后研究员和海洋技术博士研究员。Karimirad于2011年3月在挪威科技大学(NTNU)获得海洋结构博士学位。他曾在挪威卓越中心CeSOS(船舶和海洋结构中心)工作。他在CeSOS的博士后研究是NOWITECH(挪威海上风电技术研究中心)项目的一部分，在进行自己的研究的同时，他积极参与为硕士和博士学生提供建议。他参与的项目与海上可再生能源结构有关，涉及海上风力涡轮机设计的不同方面;解决疲劳和极限状态分析;风力机传动系统数值模拟研究评估波浪和风能装置组合的使用;并对海上风力涡轮机的故障和瞬态事件进行研究。Karimirad的专长是设计、分析和测试海上可再生能源(ORE)结构，特别是海上风力涡轮机。他曾担任多个国际期刊和会议的审稿人，如ASME的年度OMAE会议。他曾担任《航运与海洋工程杂志》的编辑委员会成员，目前担任《海洋工程》(Elsevier)、《应用海洋研究》(Elsevier)、《国际海岸与近海工程杂志》和《能源》(MDPI)的编辑委员会成员。他还是美国机械工程师协会海上力学和北极工程杂志(JOMAE)和能源研究前沿杂志的副主编。Karimirad是IMarEST(英国海洋工程，科学与技术研究所)的研究员，高等教育学院(英国)的研究员，美国机械工程师协会(ASME)的活跃成员，以及英国的特许机械工程师。他最近被选为英国机械工程师学会会员。Karimirad的专业知识涵盖了海上力学、流体力学和结构工程的突出方面。具体的研究领域涉及海上风力和潮汐涡轮机的动态响应，以及受波浪、电流和风作用的波浪能转换器。 他已经在NOWITECH工作了8年，并为海上风电应用进行了数值模拟和海洋盆地测试(通过数值分析)。此外，他还参与了多个欧洲合作项目，如H2020 LIFES50+，欧盟IPRWind和欧盟FP7 dtoocean。在过去的15年里，Karimirad在海上可再生能源领域的研究记录包括110多篇关于该主题的科学出版物。他被引用超过2300次，h指数为26,i10指数为35。目前，他是支持北爱尔兰40万英镑的浮动太阳能脱碳项目的首席研究员(30万英镑现金和来自四个工业合作伙伴的10万英镑实物支持)。此外，他还是海上风能、浮动太阳能和波浪能等几个不同项目的项目负责人，总金额为85万英镑。这些资助包括SolarTwin:浮动太阳能电池板的数字孪生寿命响应(127万英镑)，海底固定海上风电场可靠和经济高效的再供电决策支持框架(27万英镑)，以及最近获得批准的LEAP项目HI:美国-爱尔兰研发合作伙伴关系，CoWEC。海浪能量转换的控制协同设计，由DfE UKRI资助30万英镑(英国贝尔法斯特女王大学，爱尔兰梅努斯大学，美国弗吉尼亚理工大学和美国密歇根大学之间为期4年的合作研究)。Karimirad目前指导着两名博士后研究员和四名博士生。他指导了超过25名硕士和bb100名学生。他的两名博士生已经成功地通过了论文答辩和口试。Karimirad博士最近的工作重点是海上可再生能源结构的数值和实验评估，以支持海上风能和浮动太阳能的应用。这项工作包括使用波浪槽测试进行水动力分析，以及数值模拟和代码开发，以便更好地估计响应和负载效应。图2描述了这项工作的一些示例。Karimirad认为，通过更好地估计负荷和负荷效应，进一步降低海上可再生能源(ORE)结构的风险，是降低能源平准化成本(LCOE)和绿色能源持续增长的关键，从而实现净零排放和可持续性。他在QUB的团队正在开发先进的数值代码，通过实验验证，可以准确评估矿石结构的随机动态响应，同时支持脱碳和可持续的海上技术发展;这项研究的一个例子可以在参考文献bbb中找到。张心舒(图3)是中国上海交通大学船舶与海洋工程系的教授。2014年加入上海交通大学之前，他曾就职于SBM、Technip、美国船级社(ABS)和美国KBR。他在海洋流体动力学领域有20多年的研究经验，特别是在非线性波-波和波-结构相互作用方面。他在学术界和工业界都有很强的工作背景。2007年3月获美国密歇根大学安娜堡分校海洋流体力学博士学位。在该行业工作期间，他积极参与各种石油和天然气勘探平台的设计和分析。特别是，他广泛参与了雪佛龙最大的半潜式浮式生产装置Jack St. Malo (JSM)的设计。张博士从事不同的项目，专注于海上平台的设计、分析和测试;这些平台包括桅杆、张力腿平台(TLPs)、浮式生产储存和卸载(FPSO)系统和半潜式平台。凭借他的实践经验，张博士在上海交通大学的团队开发了一种新的设计策略，用于优化石油和天然气平台，该策略使用基于代理模型的计算工具。这种策略对于设计浮动概念尺寸的工程师很有价值，因为它可以显著减少计算时间，并使设计迭代循环更有效。目前，张博士是《海洋工程》(Elsevier)和《流体动力学杂志》(b施普林格)的编辑委员会成员。他还是美国机械工程师协会(ASME)海上力学和北极工程杂志(JOMAE)的副主编。他在国际拖舱会议(ITTC)上非常活跃。2017年至2021年，任第29届ITTC环境条件建模专家委员会技术委员会委员。从2021年到2024年，他担任第30届ittc风力和风力辅助船舶专家委员会的技术委员会成员。张教授的专业知识涵盖了海洋流体力学的各个方面。 他在非线性波-波和波-结构相互作用领域有着长期的
{"title":"Profiles of Two JOMAE Associate Editors (The Fifth in a Continuing Series)","authors":"","doi":"10.1115/1.4056881","DOIUrl":"https://doi.org/10.1115/1.4056881","url":null,"abstract":"Since 1987, the ASME Journal of Offshore Mechanics and Arctic Engineering has been a dependable source for the dissemination of the studies of researchers, practitioners, and interested parties working in the ocean, offshore, arctic, and related fields. It is where one can read and learn from peer-reviewed research on all aspects of analysis, design, and technology development in these fields. The journal’s goal remains one of showcasing fundamental research and development studies; it has also featured review articles and perspectives on well-established as well as emerging topics.As I did in a recent editorial that appeared in the April 2022 issue of this journal [1] (and which cited three earlier similar editorials that appeared in June 2019, August 2020, and October 2021), I am seeking to once again highlight the efforts and dedication of an international team of Associate Editors, focusing on profiles of two of them at a time. It is this team that helps keep the journal vibrant, relevant, and timely in allowing the exchange of theoretical and practical developments in the ocean, offshore, and arctic engineering arena.Today, the journal has 38 Associate Editors who cover the breadth of areas in offshore mechanics and arctic engineering; they represent 14 countries, namely, Australia, Canada, China, Denmark, Finland, Germany, India, Italy, Japan, Mexico, Norway, Singapore, the United Kingdom, and the United States. With support from hard-working reviewers, these dedicated Associate Editors help this journal release six issues each year.I am truly delighted to continue this series of editorials profiling, each time, two Associate Editors and highlighting their expertise areas and accomplishments. I encourage you to learn about previously profiled Associate Editors [1]. In this issue, I present to you two Associate Editors—Dr. Madjid Karimirad, Associate Professor of Marine and Coastal Engineering at Queen’s University, Belfast, United Kingdom, and Dr. Xinshu Zhang, Professor of Naval Architecture and Ocean Engineering at Shanghai Jiao Tong University, China.Dr. Madjid Karimirad (Fig. 1) is an associate professor (Senior Lecturer) in marine and coastal engineering at Queen’s University Belfast (QUB) in the United Kingdom. Before he joined QUB in 2017, he was a Research Scientist at MARINTEK (Norwegian Marine Technology Research Institute) and SINTEF Ocean, Norway. He has more than 15 years of research experience dealing with marine structures and offshore technology. His background in both academia and industry is strong; he has worked as a research scientist and as a post-doctoral fellow and Ph.D. researcher in offshore technology, prior to his current appointment.Dr. Karimirad earned his Ph.D. in March 2011 in Marine Structures from the Norwegian University of Science and Technology (NTNU). He was employed previously at CeSOS (Centre for Ships and Ocean Structures), a Centre of Excellence in Norway. His post-doctoral research at CeSOS was part","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135583084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This article presents an extreme value analysis on data of significant wave height based on time-series simulation. A method to simulate time series with given marginal distribution and preserving the autocorrelation structure in the data is applied to significant wave height data. Then, extreme value analysis is performed by simulating from the fitted time-series model that preserves both the marginal probability distribution and the autocorrelation. In this way, the effect of serial correlation on the extreme values can be taken into account, without subsampling and de-clustering of the data. The effect of serial correlation on estimating extreme wave conditions have previously been highlighted, and failure to account for this effect will typically lead to an overestimation of extreme conditions. This is demonstrated by this study, which compares extreme value estimates from the simulated times-series model with estimates obtained directly from the marginal distribution assuming that 3-h significant wave heights are independent and identically distributed. A dataset of significant wave height provided as part of a second benchmark exercise on environmental extremes that was presented at OMAE 2021 has been analyzed. This article is an extension of a study presented at OMAE 2022 (OMAE2022-78795) and includes additional preprocessing of the data to account for seasonality and new results.
{"title":"Analyzing Extreme Sea State Conditions by Time-Series Simulation Accounting for Seasonality","authors":"Erik Vanem","doi":"10.1115/1.4056786","DOIUrl":"https://doi.org/10.1115/1.4056786","url":null,"abstract":"Abstract This article presents an extreme value analysis on data of significant wave height based on time-series simulation. A method to simulate time series with given marginal distribution and preserving the autocorrelation structure in the data is applied to significant wave height data. Then, extreme value analysis is performed by simulating from the fitted time-series model that preserves both the marginal probability distribution and the autocorrelation. In this way, the effect of serial correlation on the extreme values can be taken into account, without subsampling and de-clustering of the data. The effect of serial correlation on estimating extreme wave conditions have previously been highlighted, and failure to account for this effect will typically lead to an overestimation of extreme conditions. This is demonstrated by this study, which compares extreme value estimates from the simulated times-series model with estimates obtained directly from the marginal distribution assuming that 3-h significant wave heights are independent and identically distributed. A dataset of significant wave height provided as part of a second benchmark exercise on environmental extremes that was presented at OMAE 2021 has been analyzed. This article is an extension of a study presented at OMAE 2022 (OMAE2022-78795) and includes additional preprocessing of the data to account for seasonality and new results.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":"434 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135583740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Increased deployment of offshore wind turbines is seen as an important pathway to increase green renewable energy production. Improved and rapid identification of extreme events and evaluation of hydrodynamic loads due to such events is essential to reduce the cost of energy production. Numerical modelling to pre-screen sea states and identify the crucial events to prioritise model tests will make a major contribution to reduce design times and costs for such structures. In this effort, a highly efficient and nonlinear numerical model based on the Laplace equations is used to generate undisturbed wave kinematics. Such a simulation is used to identify extreme wave events in a sea state realisation and further, the wave loading due to such events are evaluated using Morison Formula. Events screened in this manner can then be transferred to a high-resolution model such as a Navier-Stokes equations-based solver to investigate the hydrodynamics in details. The implementation of such a method in the open-source hydrodynamic model REEF3D is presented in this work.
{"title":"Identification and Investigation of Extreme Events using an Arbitrary Lagrangian Eulerian approach with a Laplace equation Solver and Coupling to a Navier-Stokes Solver","authors":"A. Kamath, Weizhi Wang, Csaba Pákozdi, H. Bihs","doi":"10.1115/1.4057014","DOIUrl":"https://doi.org/10.1115/1.4057014","url":null,"abstract":"\u0000 Increased deployment of offshore wind turbines is seen as an important pathway to increase green renewable energy production. Improved and rapid identification of extreme events and evaluation of hydrodynamic loads due to such events is essential to reduce the cost of energy production. Numerical modelling to pre-screen sea states and identify the crucial events to prioritise model tests will make a major contribution to reduce design times and costs for such structures. In this effort, a highly efficient and nonlinear numerical model based on the Laplace equations is used to generate undisturbed wave kinematics. Such a simulation is used to identify extreme wave events in a sea state realisation and further, the wave loading due to such events are evaluated using Morison Formula. Events screened in this manner can then be transferred to a high-resolution model such as a Navier-Stokes equations-based solver to investigate the hydrodynamics in details. The implementation of such a method in the open-source hydrodynamic model REEF3D is presented in this work.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42630626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The turbulent flow characteristics over bed-mounted three different cubical shape bluff bodies is examined experimentally in the water channel facility. The steady and fluctuating flow fields are investigated to analyse the effect of corner radius and shapes of the bluff body on turbulent flow structure, particularly in the wake region. It is found that the sharp corner region, significantly impacts the flow separation and alters the characteristics of the shear-layer flow. In particular, the relatively subtle change in geometry resulted in a remarkable variation of the mean flow in the wake is observed. The anisotropic nature of flow is analysed using the turbulence triangle for the different cubical structures. The variation of the turbulent length scales are presented in the near and far wake region of the submerged obstacles.
{"title":"Turbulent anisotropy and length scale variation over multiple shaped structure","authors":"Pankaj Kumar Raushan, S. K. Singh, K. Debnath","doi":"10.1115/1.4057007","DOIUrl":"https://doi.org/10.1115/1.4057007","url":null,"abstract":"\u0000 The turbulent flow characteristics over bed-mounted three different cubical shape bluff bodies is examined experimentally in the water channel facility. The steady and fluctuating flow fields are investigated to analyse the effect of corner radius and shapes of the bluff body on turbulent flow structure, particularly in the wake region. It is found that the sharp corner region, significantly impacts the flow separation and alters the characteristics of the shear-layer flow. In particular, the relatively subtle change in geometry resulted in a remarkable variation of the mean flow in the wake is observed. The anisotropic nature of flow is analysed using the turbulence triangle for the different cubical structures. The variation of the turbulent length scales are presented in the near and far wake region of the submerged obstacles.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43760237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haoyu Ding, J. Zang, Jin Peng, D. Ning, Xuanlie Zhao, Yingyi Liu, C. Blenkinsopp, Qiang Chen
Wave energy converters (WECs) are built to extract wave energy. However, this kind of device is still expensive for commercial utilisation. To cut down the cost of WECs by sharing the construction cost with breakwaters, an integrated cylindrical WEC-type breakwater system that includes a cylindrical WEC array in front of a very long breakwater is proposed to extract wave energy and attenuate incident waves. This paper aims to optimise the performance of the integrated cylindrical WEC-type breakwater system. A computational fluid dynamics tool, OpenFOAM®, and a potential flow theory-based solver, HAMS®, are utilised. OpenFOAM® provides viscosity corrections to a modified version of HAMS® in order to accurately and efficiently predict the integrated system's performance. Parametric studies are conducted to optimise the integrated system, and a novel setup with an extra arc structure is found to significantly improve the performance of the integrated system.
{"title":"Optimisation of the Hydrodynamic Performance of a wave energy converter in an Integrated Cylindrical WEC-Type Breakwater System","authors":"Haoyu Ding, J. Zang, Jin Peng, D. Ning, Xuanlie Zhao, Yingyi Liu, C. Blenkinsopp, Qiang Chen","doi":"10.1115/1.4056942","DOIUrl":"https://doi.org/10.1115/1.4056942","url":null,"abstract":"Wave energy converters (WECs) are built to extract wave energy. However, this kind of device is still expensive for commercial utilisation. To cut down the cost of WECs by sharing the construction cost with breakwaters, an integrated cylindrical WEC-type breakwater system that includes a cylindrical WEC array in front of a very long breakwater is proposed to extract wave energy and attenuate incident waves. This paper aims to optimise the performance of the integrated cylindrical WEC-type breakwater system. A computational fluid dynamics tool, OpenFOAM®, and a potential flow theory-based solver, HAMS®, are utilised. OpenFOAM® provides viscosity corrections to a modified version of HAMS® in order to accurately and efficiently predict the integrated system's performance. Parametric studies are conducted to optimise the integrated system, and a novel setup with an extra arc structure is found to significantly improve the performance of the integrated system.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48106472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Taemin Heo, Ding-Peng Liu, L. Manuel, J. Correia, P. Mendes
An offshore energy transition, even if only a gradual one, from carbon-emitting fossil fuel extraction to cleaner sources is recommended, if we are to slow the harmful impacts of climate change. The potential for sustainable reuse of decommissioned offshore jacket platforms to support wind turbines is being considered as an attractive proposition in such a transition. To maximize the benefits of such reuse of assets, what is needed is a rational optimization strategy that considers the remaining life of a repurposed platform, associated retrofit and construction costs, and a future period of gross renewable energy generation following installation of the wind turbine. We outline a study that employs a fatigue reliability-based framework, based on the global fatigue approach and Palmgren-Miner's rule, to aid in such sustainable reuse planning and optimization. The framework proposed identifies an optimized reuse plan that incorporates metocean data analysis, structural analysis, life-cycle evaluation, and revenue optimization. We employ a case study and sustainable reuse scenario for a site in the vicinity of Porto (Leixoes), Portugal.
{"title":"Assessing Fatigue Damage in the Reuse of a Decommissioned Offshore Jacket Platform to Support a Wind Turbine","authors":"Taemin Heo, Ding-Peng Liu, L. Manuel, J. Correia, P. Mendes","doi":"10.1115/1.4056943","DOIUrl":"https://doi.org/10.1115/1.4056943","url":null,"abstract":"\u0000 An offshore energy transition, even if only a gradual one, from carbon-emitting fossil fuel extraction to cleaner sources is recommended, if we are to slow the harmful impacts of climate change. The potential for sustainable reuse of decommissioned offshore jacket platforms to support wind turbines is being considered as an attractive proposition in such a transition. To maximize the benefits of such reuse of assets, what is needed is a rational optimization strategy that considers the remaining life of a repurposed platform, associated retrofit and construction costs, and a future period of gross renewable energy generation following installation of the wind turbine. We outline a study that employs a fatigue reliability-based framework, based on the global fatigue approach and Palmgren-Miner's rule, to aid in such sustainable reuse planning and optimization. The framework proposed identifies an optimized reuse plan that incorporates metocean data analysis, structural analysis, life-cycle evaluation, and revenue optimization. We employ a case study and sustainable reuse scenario for a site in the vicinity of Porto (Leixoes), Portugal.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43170958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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