首页 > 最新文献

Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme最新文献

英文 中文
Experimental study on the effect of fines content on the frost swelling characteristics of coarse-grained soil in canal base under open system 开放体系下细粒含量对渠底粗粒土冻胀特性影响的试验研究
IF 1.6 4区 工程技术 Q3 ENGINEERING, MECHANICAL Pub Date : 2023-07-11 DOI: 10.1115/1.4062931
Miao Wang, Ming Hai, Anshuang Su, S. Meng, Hailong Mu, Yanxiu Guo
Engineering usually considers coarse-grained soils as nonfrost swelling soils, but serious frost swelling still occurs in coarse-grained canal bases, which is directly related to the recharge conditions and the fine particle content in the soil. Little attention is currently paid to the effect of different fine particle contents on coarse-grained soil frost swelling, especially after the fine particle admixture content exceeds 16%. This paper considers the characteristics of coarse-grained soils in water conservancy projects with fines content between 0% and 50%. The coarse-grained soils with 5%, 15%, 25%, 35% and 45% fines content were designed for freezing and swelling tests. The evolution of temperature and moisture fields and the amount of freezing and swelling of coarse-grained soils during the freezing process were studied by using servo-type freezing and swelling and thawing tester. The experimental results show that the cooling process of soil samples can be divided into a rapid cooling stage, a slow cooling stage and a freezing stabilization stage. The cooling rate and the frost heave amount with increasing fines content showed a trend of first increasing and then decreasing.
工程上通常将粗粒土视为非冻胀土,但粗粒渠基仍会发生严重的冻胀,这与补给条件和土中细粒含量直接相关。不同细颗粒掺量对粗粒土霜胀的影响,特别是细颗粒掺量超过16%后,目前研究较少。本文研究了细粒含量为0% ~ 50%的水利工程中粗粒土的特点。设计细粒含量分别为5%、15%、25%、35%和45%的粗粒土进行冻结和膨胀试验。采用伺服式冻胀融试验装置,研究了粗粒土在冻结过程中温度、水分场的演变及冻胀量。试验结果表明,土样的冷却过程可分为快速冷却阶段、缓慢冷却阶段和冻结稳定阶段。随着细粒含量的增加,冷却速率和冻胀量呈现先增大后减小的趋势。
{"title":"Experimental study on the effect of fines content on the frost swelling characteristics of coarse-grained soil in canal base under open system","authors":"Miao Wang, Ming Hai, Anshuang Su, S. Meng, Hailong Mu, Yanxiu Guo","doi":"10.1115/1.4062931","DOIUrl":"https://doi.org/10.1115/1.4062931","url":null,"abstract":"\u0000 Engineering usually considers coarse-grained soils as nonfrost swelling soils, but serious frost swelling still occurs in coarse-grained canal bases, which is directly related to the recharge conditions and the fine particle content in the soil. Little attention is currently paid to the effect of different fine particle contents on coarse-grained soil frost swelling, especially after the fine particle admixture content exceeds 16%. This paper considers the characteristics of coarse-grained soils in water conservancy projects with fines content between 0% and 50%. The coarse-grained soils with 5%, 15%, 25%, 35% and 45% fines content were designed for freezing and swelling tests. The evolution of temperature and moisture fields and the amount of freezing and swelling of coarse-grained soils during the freezing process were studied by using servo-type freezing and swelling and thawing tester. The experimental results show that the cooling process of soil samples can be divided into a rapid cooling stage, a slow cooling stage and a freezing stabilization stage. The cooling rate and the frost heave amount with increasing fines content showed a trend of first increasing and then decreasing.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43853232","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}
引用次数: 0
Bragg scattering of surface gravity waves by a submerged composite wavy porous plate 浸没复合波纹多孔板对表面重力波的Bragg散射
IF 1.6 4区 工程技术 Q3 ENGINEERING, MECHANICAL Pub Date : 2023-07-04 DOI: 10.1115/1.4062897
A. K. Mohapatra, T. Sahoo
Surface gravity wave interaction of composite wavy porous plate is studied by developing a numerical model using the boundary element method in the context of two-dimensional linear potential theory. Bragg scattering phenomenon is studied by considering the linearized pressure drop condition known as Darcy's law passing through the porous structure. Numerical results are obtained through the boundary element method for the special limiting case of the existing previous literature to authenticate the accuracy of the numerical solution. The influence of wave and structural design parameters such as the number of ripple wavelengths of the wavy plate, relative plate length, structural porosities and relative submergence depth on hydrodynamics properties such as reflection, transmission, horizontal wave load and vertical wave coefficients are discussed. The study results of composite wavy porous plate indicate improved hydrodynamic performance as compared to the horizontal porous plate and wavy porous plate. This study is significant for practical applications in coastal engineering environments.
在二维线性势理论的背景下,利用边界元方法建立了复合材料波纹多孔板的表面-重力波相互作用的数值模型。通过考虑穿过多孔结构的线性压降条件,即达西定律,研究了布拉格散射现象。对于现有文献中的特殊极限情况,通过边界元方法获得了数值结果,以验证数值解的准确性。讨论了波浪和结构设计参数,如波纹板的波纹波长数、相对板长、结构孔隙率和相对淹没深度,对反射、透射、水平波荷载和垂直波系数等流体力学特性的影响。复合波纹多孔板的研究结果表明,与水平多孔板和波纹多孔板相比,其流体力学性能有所提高。该研究对海岸工程环境的实际应用具有重要意义。
{"title":"Bragg scattering of surface gravity waves by a submerged composite wavy porous plate","authors":"A. K. Mohapatra, T. Sahoo","doi":"10.1115/1.4062897","DOIUrl":"https://doi.org/10.1115/1.4062897","url":null,"abstract":"\u0000 Surface gravity wave interaction of composite wavy porous plate is studied by developing a numerical model using the boundary element method in the context of two-dimensional linear potential theory. Bragg scattering phenomenon is studied by considering the linearized pressure drop condition known as Darcy's law passing through the porous structure. Numerical results are obtained through the boundary element method for the special limiting case of the existing previous literature to authenticate the accuracy of the numerical solution. The influence of wave and structural design parameters such as the number of ripple wavelengths of the wavy plate, relative plate length, structural porosities and relative submergence depth on hydrodynamics properties such as reflection, transmission, horizontal wave load and vertical wave coefficients are discussed. The study results of composite wavy porous plate indicate improved hydrodynamic performance as compared to the horizontal porous plate and wavy porous plate. This study is significant for practical applications in coastal engineering environments.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49194290","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}
引用次数: 0
An Explanation for the Flutter Paradox in the Supercritical Region of a Simply-Supported Fluid-Conveying Pipe 简支流体输送管超临界区颤振悖论的一种解释
IF 1.6 4区 工程技术 Q3 ENGINEERING, MECHANICAL Pub Date : 2023-06-26 DOI: 10.1115/1.4062718
Ding Ming, Meng Shuai, Liu Zhen, Zhang Junhan
Employing traditional Galerkin method, a coupled-mode flutter is predicted in the supercritical region of simply-supported pipes which constitutes a paradox since the internal flow effect is conservative and there is no energy to sustain the oscillation. Although there is a consensus that the flutter does not exist, the intrinsic mechanism remains to be clarified. This study has found that the internal flow induced Coriolis force term cannot be decoupled in traditional Galerkin method which leads to the dissatisfaction of the convergence conditions required in weighted residual approach (WRA). Moreover, the disparities in the predicted complex frequencies have been witnessed at different base function numbers when the internal flow velocity is sufficiently large. A modified Galerkin method adopting a new set of weighting functions is proposed based on WRA, and the Coriolis force term disappears by use of the orthogonality relations (it is stated that the Coriolis force is not directly omitted). Thus, a convergent solution for the set of residual functions which are identically equal to zeros can be guaranteed. Employing the modified method, the convergence in simulations is confirmed and the flutter phenomenon does not occur. This study can be a workbench for the study on the unsolved or partly solved issues in simulations of fluid-conveying pipes. Moreover, it has demonstrated that the predictions in traditional Galerkin method overestimate the natural frequencies, and it becomes more profound in higher-order natural modes at larger internal flow velocities which are of practice significance for dynamic analysis of flexible pipeline systems.
采用传统的伽辽金方法预测简支管超临界区域的耦合模态颤振,由于管内流动效应是保守的,且没有能量维持振荡,这就形成了一个悖论。虽然人们一致认为颤振不存在,但其内在机制仍有待阐明。研究发现,传统的Galerkin方法不能解耦内部流动引起的科里奥利力项,导致加权残差法(WRA)的收敛条件不满足。此外,当内部流速足够大时,不同基函数数下预测的复频率存在差异。提出了一种基于WRA的改进Galerkin方法,该方法采用了一组新的加权函数,并利用正交关系消除了科里奥利力项(说明科里奥利力不直接省略)。由此,可以保证残差函数集的收敛解同等于零。采用改进后的方法,验证了仿真结果的收敛性,并且没有出现颤振现象。本研究可为流体输送管道模拟中尚未解决或部分解决的问题的研究提供一个工作平台。此外,传统伽辽金方法的预测过高估计了固有频率,并且在较大的内流速下,对高阶固有模态的预测更加深刻,这对柔性管道系统的动态分析具有实际意义。
{"title":"An Explanation for the Flutter Paradox in the Supercritical Region of a Simply-Supported Fluid-Conveying Pipe","authors":"Ding Ming, Meng Shuai, Liu Zhen, Zhang Junhan","doi":"10.1115/1.4062718","DOIUrl":"https://doi.org/10.1115/1.4062718","url":null,"abstract":"\u0000 Employing traditional Galerkin method, a coupled-mode flutter is predicted in the supercritical region of simply-supported pipes which constitutes a paradox since the internal flow effect is conservative and there is no energy to sustain the oscillation. Although there is a consensus that the flutter does not exist, the intrinsic mechanism remains to be clarified. This study has found that the internal flow induced Coriolis force term cannot be decoupled in traditional Galerkin method which leads to the dissatisfaction of the convergence conditions required in weighted residual approach (WRA). Moreover, the disparities in the predicted complex frequencies have been witnessed at different base function numbers when the internal flow velocity is sufficiently large. A modified Galerkin method adopting a new set of weighting functions is proposed based on WRA, and the Coriolis force term disappears by use of the orthogonality relations (it is stated that the Coriolis force is not directly omitted). Thus, a convergent solution for the set of residual functions which are identically equal to zeros can be guaranteed. Employing the modified method, the convergence in simulations is confirmed and the flutter phenomenon does not occur. This study can be a workbench for the study on the unsolved or partly solved issues in simulations of fluid-conveying pipes. Moreover, it has demonstrated that the predictions in traditional Galerkin method overestimate the natural frequencies, and it becomes more profound in higher-order natural modes at larger internal flow velocities which are of practice significance for dynamic analysis of flexible pipeline systems.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44877632","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}
引用次数: 0
A Novel Free-Standing Riser Concept for Deepwater Developments 用于深水开发的新型独立式立管概念
4区 工程技术 Q3 ENGINEERING, MECHANICAL Pub Date : 2023-06-22 DOI: 10.1115/1.4062688
Carlos Terencio Pires Bomfimsilva, Theodoro Antoun Netto
Abstract Free-standing hybrid risers (FSHR) are well established in deepwater field developments in the oil and gas industry. The major advantages foreseen for the FSHR are the possibility of safely anticipating production and requiring significantly reduced payloads at the floating production unit. This work addresses the feasibility of a novel proposed optimized concept, the free-standing integrated riser (FSIR), where the pipeline is integrated into the riser by means of a transition section, which is kept in place by a multiple line mooring system, developed to keep the functionality and integrity of the entire riser along its lifetime. The work provides the findings from numerical analysis simulated in orcaflex, a finite element simulation software dedicated to global analysis of risers, considering the design criteria provided in API 2RD Standard. As part of the FSIR evaluation, screening static analysis was performed to identify the most promising configurations for the multiple line mooring system, followed by a series of dynamic analyses to evaluate the behavior of the riser in extreme conditions. In addition, several investigations were performed to assess the functionality and the robustness of the system, including parametric studies to check for installation and dimensional tolerances, assessment of fatigue damage, and checking the impact of pipe size on the design. The results show that the proposed novel FSIR concept can provide a practical and economical solution for deepwater projects.
独立式混合式立管(FSHR)在油气行业的深水油田开发中得到了广泛应用。FSHR的主要优点是可以安全预测生产,并且大大减少了浮式生产单元的有效载荷。这项工作解决了一种新提出的优化概念的可行性,即独立式集成立管(FSIR),其中管道通过过渡段集成到立管中,该过渡段由多管系泊系统保持在原位,以保持整个立管在其使用寿命期间的功能和完整性。考虑到API 2RD标准中提供的设计准则,该工作提供了在orcaflex中模拟的数值分析结果,orcaflex是一个致力于立管全局分析的有限元模拟软件。作为FSIR评估的一部分,进行了筛选静态分析,以确定最适合多缆系泊系统的配置,然后进行了一系列动态分析,以评估隔水管在极端条件下的行为。此外,研究人员还对系统的功能和稳健性进行了评估,包括参数化研究,以检查安装和尺寸公差,评估疲劳损伤,以及检查管道尺寸对设计的影响。结果表明,提出的新型FSIR概念可以为深水项目提供一种实用且经济的解决方案。
{"title":"A Novel Free-Standing Riser Concept for Deepwater Developments","authors":"Carlos Terencio Pires Bomfimsilva, Theodoro Antoun Netto","doi":"10.1115/1.4062688","DOIUrl":"https://doi.org/10.1115/1.4062688","url":null,"abstract":"Abstract Free-standing hybrid risers (FSHR) are well established in deepwater field developments in the oil and gas industry. The major advantages foreseen for the FSHR are the possibility of safely anticipating production and requiring significantly reduced payloads at the floating production unit. This work addresses the feasibility of a novel proposed optimized concept, the free-standing integrated riser (FSIR), where the pipeline is integrated into the riser by means of a transition section, which is kept in place by a multiple line mooring system, developed to keep the functionality and integrity of the entire riser along its lifetime. The work provides the findings from numerical analysis simulated in orcaflex, a finite element simulation software dedicated to global analysis of risers, considering the design criteria provided in API 2RD Standard. As part of the FSIR evaluation, screening static analysis was performed to identify the most promising configurations for the multiple line mooring system, followed by a series of dynamic analyses to evaluate the behavior of the riser in extreme conditions. In addition, several investigations were performed to assess the functionality and the robustness of the system, including parametric studies to check for installation and dimensional tolerances, assessment of fatigue damage, and checking the impact of pipe size on the design. The results show that the proposed novel FSIR concept can provide a practical and economical solution for deepwater projects.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136178680","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}
引用次数: 0
Torus-Shaped Wave Energy Converter Attached to a Hinged Arm 连接在铰链臂上的环形波能转换器
4区 工程技术 Q3 ENGINEERING, MECHANICAL Pub Date : 2023-06-13 DOI: 10.1115/1.4062624
Mojtaba Kamarlouei, Thiago Hallak, Jose Gaspar, Miguel Calvario, Carlos Guedes Soares
Abstract This study presents the adaptation of a torus-shaped prime mover of a wave energy converter to an onshore or nearshore fixed platform by a hinged arm, with the objective of providing more favorable conditions for device survivability at extreme sea state. An optimization code is developed to obtain the best prime mover and arm geometries, as well as the power take-off parameters, with the objective to maximize the total absorbed power. In this paper, the power take-off system is modeled as a simplified damper and spring system, where the parameters are optimized for the power absorption of the wave energy converter in each sea state, whereas the optimization process is performed with a genetic algorithm. The results indicate that better survivability performance may be achieved with the torus-shaped prime mover in comparison to a conventional one without a moonpool, despite a relatively lower wave-absorbed power.
摘要本研究提出了将波浪能转换器的环形原动机通过铰接臂适应于陆上或近岸固定平台,目的是为设备在极端海况下的生存能力提供更有利的条件。开发了优化程序,以获得最佳原动机和手臂几何形状以及功率输出参数,目标是使总吸收功率最大化。本文将动力输出系统建模为一个简化的阻尼弹簧系统,针对不同海况下波浪能转换器的吸能特性进行参数优化,并采用遗传算法进行优化。结果表明,与没有月池的传统原动机相比,环形原动机可以获得更好的生存性能,尽管吸波功率相对较低。
{"title":"Torus-Shaped Wave Energy Converter Attached to a Hinged Arm","authors":"Mojtaba Kamarlouei, Thiago Hallak, Jose Gaspar, Miguel Calvario, Carlos Guedes Soares","doi":"10.1115/1.4062624","DOIUrl":"https://doi.org/10.1115/1.4062624","url":null,"abstract":"Abstract This study presents the adaptation of a torus-shaped prime mover of a wave energy converter to an onshore or nearshore fixed platform by a hinged arm, with the objective of providing more favorable conditions for device survivability at extreme sea state. An optimization code is developed to obtain the best prime mover and arm geometries, as well as the power take-off parameters, with the objective to maximize the total absorbed power. In this paper, the power take-off system is modeled as a simplified damper and spring system, where the parameters are optimized for the power absorption of the wave energy converter in each sea state, whereas the optimization process is performed with a genetic algorithm. The results indicate that better survivability performance may be achieved with the torus-shaped prime mover in comparison to a conventional one without a moonpool, despite a relatively lower wave-absorbed power.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":"158 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136066135","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}
引用次数: 0
Hydrodynamic Forces on a Near-bottom Pipeline Subject to Wave-induced Boundary Layer 波浪边界层作用下近底管道的水动力
IF 1.6 4区 工程技术 Q3 ENGINEERING, MECHANICAL Pub Date : 2023-06-11 DOI: 10.1115/1.4062896
G. Yin, M. Ong, N. Ye
Hydrodynamic forces on small diameter subsea pipelines and cables placed near seabed are important for their on-bottom stability design. In offshore environments, these pipelines are usually subjected to extreme wave conditions. The present study investigates hydrodynamic forces acting on a pipeline near a flat seabed subjected to a wave-induced boundary layer flow. The Keulegan-Carpenter numbers (KC) of the wave-induced boundary layer flow are 20, 140 and 200, defined based on the pipeline diameter (D), the maximum velocity of the undisturbed near-bed orbital velocity (Uw) and the period of the incoming oscillatory flow (Tw). Reynolds number is 1 × 104 based on Uw and D. A seabed roughness ratio ks/D (ks is the Nikuradse equivalent sand roughness) of up to 0.1 and different gap ratios of G/D = 0.05~0.5 between the pipeline and the seabed are considered. Numerical simulations have been carried out based on two-dimensional (2D) Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations combined with the k-ω Shear Stress Transport (SST) turbulence model. A preliminary one-dimensional (1D) simulation is carried out to obtain a fully developed wave-induced boundary layer velocity profile, which is used as inlet flow for the 2D simulations. The numerical model is validated against the experimental data reported by Sumer et al. (1991) at KC = 10. Influences of KC, ks/D and G/D on the hydrodynamic forces and the surrounding flows are discussed in detail.
放置在海床附近的小直径海底管道和电缆上的水动力对于其海底稳定性设计非常重要。在海上环境中,这些管道通常会受到极端波浪条件的影响。本研究调查了波浪引起的边界层流动作用在平坦海床附近管道上的水动力。波浪引起的边界层流的Keulegan-Capenter数(KC)分别为20、140和200,其定义基于管道直径(D)、未扰动近床轨道速度的最大速度(Uw)和进入振荡流的周期(Tw)。基于Uw和D,雷诺数为1×104。海底粗糙度比ks/D(ks为Nikuradse等效沙粗糙度)高达0.1,管道与海底之间的不同间隙比G/D=0.05~0.5被考虑在内。基于二维(2D)非定常雷诺平均Navier-Stokes(URNS)方程和k-ω剪切应力输运(SST)湍流模型进行了数值模拟。进行了初步的一维(1D)模拟,以获得完全发展的波浪诱导边界层速度剖面,该剖面用作2D模拟的入口流。数值模型根据Sumer等人(1991)在KC=10时报告的实验数据进行了验证。详细讨论了KC、ks/D和G/D对水动力和周围流动的影响。
{"title":"Hydrodynamic Forces on a Near-bottom Pipeline Subject to Wave-induced Boundary Layer","authors":"G. Yin, M. Ong, N. Ye","doi":"10.1115/1.4062896","DOIUrl":"https://doi.org/10.1115/1.4062896","url":null,"abstract":"\u0000 Hydrodynamic forces on small diameter subsea pipelines and cables placed near seabed are important for their on-bottom stability design. In offshore environments, these pipelines are usually subjected to extreme wave conditions. The present study investigates hydrodynamic forces acting on a pipeline near a flat seabed subjected to a wave-induced boundary layer flow. The Keulegan-Carpenter numbers (KC) of the wave-induced boundary layer flow are 20, 140 and 200, defined based on the pipeline diameter (D), the maximum velocity of the undisturbed near-bed orbital velocity (Uw) and the period of the incoming oscillatory flow (Tw). Reynolds number is 1 × 104 based on Uw and D. A seabed roughness ratio ks/D (ks is the Nikuradse equivalent sand roughness) of up to 0.1 and different gap ratios of G/D = 0.05~0.5 between the pipeline and the seabed are considered. Numerical simulations have been carried out based on two-dimensional (2D) Unsteady Reynolds-Averaged Navier-Stokes (URANS) equations combined with the k-ω Shear Stress Transport (SST) turbulence model. A preliminary one-dimensional (1D) simulation is carried out to obtain a fully developed wave-induced boundary layer velocity profile, which is used as inlet flow for the 2D simulations. The numerical model is validated against the experimental data reported by Sumer et al. (1991) at KC = 10. Influences of KC, ks/D and G/D on the hydrodynamic forces and the surrounding flows are discussed in detail.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":"1 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41332640","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}
引用次数: 0
Analysis of convergence behavior for the overset mesh based numerical wave tank in OpenFOAM OpenFOAM中基于倒置网格的数值波槽收敛特性分析
IF 1.6 4区 工程技术 Q3 ENGINEERING, MECHANICAL Pub Date : 2023-06-11 DOI: 10.1115/1.4063265
Hao Chen, L. Qian, Deping Cao
This paper presents a solution verification and validation study for an overset mesh based numerical wave tank in OpenFOAM, which considers the coupling between a free-surface hydrodynamic flow model, a rigid body motion model and an overset mesh. The coupling between the rigid body motion solver and the free surface flow solver was achieved in a segregated manner. Free decay of roll motion of a barge was modelled using the numerical wave tank, and the damping coefficient was selected as the target quantity for solution verification. The least square based solution verification procedure was adopted, where one of the four types of error estimators was fit to the data in the least-square sense. Both structured and unstructured mesh were tested, and their effects on the convergence order, numerical uncertainty and error were carefully investigated. From the numerical tests, it is found that the numerical wave tank exhibits a very good convergence property for the floating body problems with structured mesh, i.e. nearly second order in space and first order in time. However, when switching the body-fitted mesh to unstructured mesh, the grid convergence is reduced to first order. Unstructured mesh does not significantly affect the convergence order in time domain, but results in a larger uncertainty due to data scattering.
本文针对OpenFOAM中基于overset网格的数值波浪槽进行了求解验证研究,该研究考虑了自由面水动力流动模型、刚体运动模型和overset网格之间的耦合。刚体运动求解器与自由表面流动求解器之间的耦合以分离的方式实现。利用数值波浪槽模拟了驳船横摇运动的自由衰减,并选择阻尼系数作为求解的目标值进行验证。采用基于最小二乘的解验证程序,其中四种误差估计量中的一种以最小二乘的方式拟合数据。对结构化网格和非结构化网格进行了测试,并仔细研究了它们对收敛阶、数值不确定性和误差的影响。数值试验表明,该数值波槽对结构网格浮体问题具有很好的收敛性,即在空间上接近二阶,在时间上接近一阶。然而,当将贴体网格转换为非结构化网格时,网格收敛降低到一阶。非结构化网格在时域上对收敛顺序没有明显影响,但由于数据的散射导致了较大的不确定性。
{"title":"Analysis of convergence behavior for the overset mesh based numerical wave tank in OpenFOAM","authors":"Hao Chen, L. Qian, Deping Cao","doi":"10.1115/1.4063265","DOIUrl":"https://doi.org/10.1115/1.4063265","url":null,"abstract":"\u0000 This paper presents a solution verification and validation study for an overset mesh based numerical wave tank in OpenFOAM, which considers the coupling between a free-surface hydrodynamic flow model, a rigid body motion model and an overset mesh. The coupling between the rigid body motion solver and the free surface flow solver was achieved in a segregated manner. Free decay of roll motion of a barge was modelled using the numerical wave tank, and the damping coefficient was selected as the target quantity for solution verification. The least square based solution verification procedure was adopted, where one of the four types of error estimators was fit to the data in the least-square sense. Both structured and unstructured mesh were tested, and their effects on the convergence order, numerical uncertainty and error were carefully investigated. From the numerical tests, it is found that the numerical wave tank exhibits a very good convergence property for the floating body problems with structured mesh, i.e. nearly second order in space and first order in time. However, when switching the body-fitted mesh to unstructured mesh, the grid convergence is reduced to first order. Unstructured mesh does not significantly affect the convergence order in time domain, but results in a larger uncertainty due to data scattering.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48286118","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}
引用次数: 0
DYNAMIC SIMULATION OF AN OFFSHORE AQUACULTURE STRUCTURE SUBJECTED TO COMBINED WAVE AND CURRENT CONDITIONS 波浪和水流共同作用下近海水产养殖结构的动力学模拟
IF 1.6 4区 工程技术 Q3 ENGINEERING, MECHANICAL Pub Date : 2023-05-25 DOI: 10.1115/1.4062623
Hui Cheng, M. Ong, Lin Li
The reliable design of offshore aquaculture structure (OAS) for fish farming in the open ocean is vital to the marine aquaculture industry in the future. However, the lack of easy-to-access numerical tools for the dynamic analysis of OAS challenges the development of marine aquaculture. This article presents a newly developed numerical library under an open-source, finite-element analysis code, Code_Aster, enabling the dynamic analysis of OAS. A numerical model of OAS is first developed using the present numerical library, and then validated against published experiments. The validation shows a good agreement in terms of structural motions and tensions in mooring lines. Subsequently, the dynamic responses of this model are analyzed under irregular waves and current conditions from field measurements on an offshore fish farm site. The results indicate that a negative mean pitch angle will occur when the current velocity is large.
远洋水产养殖结构(OAS)的可靠设计对未来海洋水产养殖业的发展至关重要。然而,缺乏易于获取的数值工具来对美洲国家组织进行动态分析,这对海洋水产养殖的发展提出了挑战。本文介绍了一个基于开源有限元分析代码Code_Aster的新开发的数值库,实现了对OAS的动态分析。首先利用现有的数值库建立了OAS的数值模型,然后根据已发表的实验进行了验证。验证结果表明,在结构运动和系缆张力方面有很好的一致性。随后,对该模型在不规则波浪和水流条件下的动态响应进行了分析。结果表明,当电流速度较大时,平均俯仰角为负。
{"title":"DYNAMIC SIMULATION OF AN OFFSHORE AQUACULTURE STRUCTURE SUBJECTED TO COMBINED WAVE AND CURRENT CONDITIONS","authors":"Hui Cheng, M. Ong, Lin Li","doi":"10.1115/1.4062623","DOIUrl":"https://doi.org/10.1115/1.4062623","url":null,"abstract":"\u0000 The reliable design of offshore aquaculture structure (OAS) for fish farming in the open ocean is vital to the marine aquaculture industry in the future. However, the lack of easy-to-access numerical tools for the dynamic analysis of OAS challenges the development of marine aquaculture. This article presents a newly developed numerical library under an open-source, finite-element analysis code, Code_Aster, enabling the dynamic analysis of OAS. A numerical model of OAS is first developed using the present numerical library, and then validated against published experiments. The validation shows a good agreement in terms of structural motions and tensions in mooring lines. Subsequently, the dynamic responses of this model are analyzed under irregular waves and current conditions from field measurements on an offshore fish farm site. The results indicate that a negative mean pitch angle will occur when the current velocity is large.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46830106","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}
引用次数: 0
Optimization of steel jackets to support offshore wind turbines using evolutionary algorithms 用进化算法优化支撑海上风力涡轮机的钢导管架
IF 1.6 4区 工程技术 Q3 ENGINEERING, MECHANICAL Pub Date : 2023-05-25 DOI: 10.1115/1.4062625
Rodrigo O Cruz, G. R. Duarte, B. Lima, B. P. Jacob
This paper presents an optimization tool for jacket structures to support Offshore Wind Turbines (OWTs). The tool incorporates several combinations of optimization algorithms and constraint handling techniques (CHTs): Genetic Algorithm; Differential Evolution (DE); Tournament Selection Method; Multiple Constraint Ranking (MCR); Adaptive Penalty Method, Helper-and-Equivalent Optimization. The objective function regards the minimization of the jacket weight; the design variables are the diameter and thickness of the tubular members. The constraints are related to natural frequencies and Ultimate Limit State criteria. The candidate solutions are evaluated by full nonlinear time-domain Finite Element coupled analyses. To assess the optimization algorithms and CHTs, a case study is presented for the standardized OWT/jacket structure from the Offshore Code Comparison Collaboration Continuation project. Firstly, a numerical model is built and validated, in terms of masses, natural frequencies and vibration modes; then, this model is employed to run the optimization tool for all combinations of optimization algorithms and CHTs. The results indicate that, while all methods lead to feasible optimal solutions that comply with the constraints and present considerable weight reductions, the best performer is the combination of the DE algorithm with the MCR constraint-handling technique.
本文提出了一种用于支撑海上风力发电机的导管架结构优化工具。该工具结合了几种优化算法和约束处理技术(CHTs)的组合:遗传算法;差分演化;比赛选拔法;多约束排序;自适应惩罚方法,辅助-等效优化。目标函数考虑夹套重量的最小化;设计变量是管状构件的直径和厚度。约束条件与固有频率和极限状态准则有关。通过全非线性时域有限元耦合分析对候选解进行了评估。为了评估优化算法和cht,本文介绍了一个来自海上代码比较协作继续项目的标准化OWT/夹套结构的案例研究。首先,从质量、固有频率和振型三个方面建立了数值模型并进行了验证;然后,利用该模型对优化算法与cht的所有组合运行优化工具。结果表明,虽然所有方法都能得到符合约束条件的可行最优解,并且能显著减轻权重,但性能最好的是将DE算法与MCR约束处理技术相结合。
{"title":"Optimization of steel jackets to support offshore wind turbines using evolutionary algorithms","authors":"Rodrigo O Cruz, G. R. Duarte, B. Lima, B. P. Jacob","doi":"10.1115/1.4062625","DOIUrl":"https://doi.org/10.1115/1.4062625","url":null,"abstract":"\u0000 This paper presents an optimization tool for jacket structures to support Offshore Wind Turbines (OWTs). The tool incorporates several combinations of optimization algorithms and constraint handling techniques (CHTs): Genetic Algorithm; Differential Evolution (DE); Tournament Selection Method; Multiple Constraint Ranking (MCR); Adaptive Penalty Method, Helper-and-Equivalent Optimization. The objective function regards the minimization of the jacket weight; the design variables are the diameter and thickness of the tubular members. The constraints are related to natural frequencies and Ultimate Limit State criteria. The candidate solutions are evaluated by full nonlinear time-domain Finite Element coupled analyses. To assess the optimization algorithms and CHTs, a case study is presented for the standardized OWT/jacket structure from the Offshore Code Comparison Collaboration Continuation project. Firstly, a numerical model is built and validated, in terms of masses, natural frequencies and vibration modes; then, this model is employed to run the optimization tool for all combinations of optimization algorithms and CHTs. The results indicate that, while all methods lead to feasible optimal solutions that comply with the constraints and present considerable weight reductions, the best performer is the combination of the DE algorithm with the MCR constraint-handling technique.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44804071","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}
引用次数: 0
Response Mitigation of Floating Platform by Porous-Media-Tuned Liquid Dampers 多孔介质调谐液体阻尼器对浮式平台响应的抑制
4区 工程技术 Q3 ENGINEERING, MECHANICAL Pub Date : 2023-05-19 DOI: 10.1115/1.4062292
Wen-Huai Tsao, Ying-Chuan Chen, Christopher Kees, Lance Manuel
Abstract A porous-media-tuned liquid damper (PMTLD) can serve as an effective and economical dynamic vibration absorber. Placing porous media within a water tank can improve the capacity for energy dissipation and optimize the performance by varying its material properties. Two numerical models are adopted to simulate the sloshing problem in PMTLD and the dynamics of a floating platform in waves. Besides, the effectiveness of response mitigation can be verified numerically. The first potential-based approach employs a mixed-type boundary value problem (BVP) solver and a free-surface particle tracker. This approach not only simulates the inviscid water wave but also includes the nonlinear damping of the PMTLD via a quadratic Forchheimer term. Another equivalent mechanical model is used to reduce the degree-of-freedom of the PMTLD system. The Newmark method is incorporated to solve the rigid-body dynamics. The second viscous approach uses the finite element method (FEM) to spatially discretize the Navier–Stokes (NS) equations and handles the free surface via the volume of fluid (VOF) and the level set (LS) equations. The multiphase simulation is implemented by computational modeling toolkits, Proteus and Chrono, for the fluid and solid phases, respectively. The correlations between potential flow and two-phase NS models are presented. The PMTLD is designed by analogy with the tuned mass damper (TMD). Numerical results show that the PMTLD can effectively reduce the structure's dynamic response in terms of vibration amplitude around resonance. Such damping devices have great potential for offshore platforms and wind turbine design.
多孔介质调谐液体阻尼器(PMTLD)是一种经济有效的动态减振器。在水箱内放置多孔介质可以通过改变其材料特性来提高其耗能能力并优化其性能。采用两种数值模型模拟了PMTLD的晃动问题和浮动平台在波浪中的动力学。此外,还可以用数值方法验证响应缓解的有效性。第一种基于势的方法采用混合型边值问题求解器和自由表面粒子跟踪器。该方法不仅模拟了无粘水波,而且通过二次Forchheimer项包含了PMTLD的非线性阻尼。另一种等效力学模型用于降低PMTLD系统的自由度。采用Newmark法求解刚体动力学。第二种粘性方法采用有限元法(FEM)对Navier-Stokes (NS)方程进行空间离散,并通过流体体积(VOF)和水平集(LS)方程处理自由表面。多相模拟分别通过计算建模工具Proteus和Chrono对流体和固相进行。给出了势流与两相NS模型的相关性。PMTLD的设计方法与调谐质量阻尼器(TMD)类似。数值结果表明,PMTLD可以有效地降低结构在共振周围的振动幅值。这种阻尼装置在海上平台和风力涡轮机设计中具有很大的潜力。
{"title":"Response Mitigation of Floating Platform by Porous-Media-Tuned Liquid Dampers","authors":"Wen-Huai Tsao, Ying-Chuan Chen, Christopher Kees, Lance Manuel","doi":"10.1115/1.4062292","DOIUrl":"https://doi.org/10.1115/1.4062292","url":null,"abstract":"Abstract A porous-media-tuned liquid damper (PMTLD) can serve as an effective and economical dynamic vibration absorber. Placing porous media within a water tank can improve the capacity for energy dissipation and optimize the performance by varying its material properties. Two numerical models are adopted to simulate the sloshing problem in PMTLD and the dynamics of a floating platform in waves. Besides, the effectiveness of response mitigation can be verified numerically. The first potential-based approach employs a mixed-type boundary value problem (BVP) solver and a free-surface particle tracker. This approach not only simulates the inviscid water wave but also includes the nonlinear damping of the PMTLD via a quadratic Forchheimer term. Another equivalent mechanical model is used to reduce the degree-of-freedom of the PMTLD system. The Newmark method is incorporated to solve the rigid-body dynamics. The second viscous approach uses the finite element method (FEM) to spatially discretize the Navier–Stokes (NS) equations and handles the free surface via the volume of fluid (VOF) and the level set (LS) equations. The multiphase simulation is implemented by computational modeling toolkits, Proteus and Chrono, for the fluid and solid phases, respectively. The correlations between potential flow and two-phase NS models are presented. The PMTLD is designed by analogy with the tuned mass damper (TMD). Numerical results show that the PMTLD can effectively reduce the structure's dynamic response in terms of vibration amplitude around resonance. Such damping devices have great potential for offshore platforms and wind turbine design.","PeriodicalId":50106,"journal":{"name":"Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135574146","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}
引用次数: 0
期刊
Journal of Offshore Mechanics and Arctic Engineering-Transactions of the Asme
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1