The paper deals with comparative study of various surrogate models based approximate optimization in the structural design of the passive type deck support frame under design load conditions. The passive type deck support frame was devised to facilitate both transportation and installation of 20,000 ton class topside. Structural analysis was performed using the finite element method to evaluate the strength performance of the passive type deck support frame in its initial design stage. In the structural analysis, the strength performances were evaluated for various design load conditions. The optimum design problem based on surrogate model was formulated such that thickness sizing variables of main structure members were determined by minimizing the weight of the passive type deck support frame subject to the strength performance constraints. The surrogate models used in the approximate optimization were response surface method, Kriging model, and Chebyshev orthogonal polynomials. In the context of numerical performances, the solution results from approximate optimization were compared to actual non-approximate optimization. The response surface method among the surrogate models used in the approximate optimization showed the most appropriate optimum design results for the structure design of the passive type deck support frame. Received 4 January 2021, revised 28 January 2021, accepted 1 February 2021 Corresponding author Chang Yong Song: +82-61-450-2732, cysong@mokpo.ac.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
本文对设计荷载条件下被动式甲板支撑架结构设计中基于近似优化的各种替代模型进行了比较研究。被动式甲板支撑架的设计是为了方便2万吨级上层甲板的运输和安装。采用有限元法对被动式甲板支撑框架在初始设计阶段的强度性能进行了结构分析。在结构分析中，对各种设计荷载条件下的强度性能进行了评估。建立了基于代理模型的优化设计问题，在满足强度性能约束的前提下，以被动式甲板支撑架自重最小为目标确定主结构构件厚度尺寸变量。采用响应面法、Kriging模型和Chebyshev正交多项式进行近似优化。在数值性能方面，将近似优化的求解结果与实际的非近似优化结果进行了比较。在近似优化中所采用的替代模型中，响应面法是被动式甲板支撑架结构设计最合适的优化设计结果。通讯作者张永松:+82-61-450-2732,cysong@mokpo.ac.kr c 2021, The Korean Society of Ocean Engineers这是一篇开放获取的文章，根据创作共用署名非商业许可(http://creativecommons.org/licenses/by-nc/4.0)的条款分发，该许可允许在任何媒介上不受限制的非商业使用、分发和复制，前提是正确引用原创作品。
{"title":"Surrogate Model Based Approximate Optimization of Passive Type Deck Support Frame for Offshore Plant Float-over Installation","authors":"D. J. Lee, C. Song, Kangsu Lee","doi":"10.26748/KSOE.2021.002","DOIUrl":"https://doi.org/10.26748/KSOE.2021.002","url":null,"abstract":"The paper deals with comparative study of various surrogate models based approximate optimization in the structural design of the passive type deck support frame under design load conditions. The passive type deck support frame was devised to facilitate both transportation and installation of 20,000 ton class topside. Structural analysis was performed using the finite element method to evaluate the strength performance of the passive type deck support frame in its initial design stage. In the structural analysis, the strength performances were evaluated for various design load conditions. The optimum design problem based on surrogate model was formulated such that thickness sizing variables of main structure members were determined by minimizing the weight of the passive type deck support frame subject to the strength performance constraints. The surrogate models used in the approximate optimization were response surface method, Kriging model, and Chebyshev orthogonal polynomials. In the context of numerical performances, the solution results from approximate optimization were compared to actual non-approximate optimization. The response surface method among the surrogate models used in the approximate optimization showed the most appropriate optimum design results for the structure design of the passive type deck support frame. Received 4 January 2021, revised 28 January 2021, accepted 1 February 2021 Corresponding author Chang Yong Song: +82-61-450-2732, cysong@mokpo.ac.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128726208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The A60 class deck penetration piece is a fire-resistance apparatus installed on the deck compartment to protect lives and to prevent flame diffusion in the case of a fire accident in a ship or offshore plant. In this study, the sensitivity of the fire-resistance performance and approximation characteristics for the A60 class penetration piece was evaluated by conducting a transient heat-transfer analysis and fire test. The transient heat-transfer analysis was conducted to evaluate the fire-resistance design of the A60 class deck penetration piece, and the analysis results were verified via the fire test. The penetration-piece length, diameter, material type, and insulation density were used as the design factors (DFs), and the output responses were the weight, temperature, cost, and productivity. The quantitative effects of each DF on the output responses were evaluated using the design-of-experiments method. Additionally, an optimum design case was identified to minimize the weight of the A60 class deck penetration piece while satisfying the allowable limits of the output responses. According to the design-of-experiments results, various approximate models, e.g., a Kriging model, the response surface method, and a radial basis function-based neural network (RBFN), were generated. The design-of-experiments results were verified by the approximation results. It was concluded that among the approximate models, the RBFN was able to explore the design space of the A60 class deck penetration piece with the highest accuracy. Received 18 February 2021, revised 5 March 2021, accepted 12 March 2021 Corresponding author Chang Yong Song: +82-61-450-2732, cysong@mokpo.ac.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
A60级甲板穿透件是安装在甲板舱室上的防火装置，用于在船舶或海上设备发生火灾事故时保护生命和防止火焰扩散。在本研究中，通过瞬态传热分析和火灾试验，对A60级侵彻片耐火性能和近似特性的敏感性进行了评估。对A60级甲板侵彻片的耐火设计进行了瞬态传热分析，并通过火灾试验对分析结果进行了验证。以穿片长度、直径、材料类型和绝缘密度作为设计因子，输出响应为重量、温度、成本和生产率。使用实验设计法评估了每种DF对输出响应的定量影响。此外，在满足输出响应允许极限的情况下，确定了A60级甲板穿透件重量最小的最佳设计方案。根据实验设计结果，生成了Kriging模型、响应面法和基于径向基函数的神经网络(RBFN)等近似模型。仿真结果验证了实验设计的正确性。结果表明，在几种近似模型中，RBFN能够以最高的精度探索A60级甲板侵穿件的设计空间。通讯作者张永松:+82-61-450-2732,cysong@mokpo.ac.kr c 2021, The Korean Society of Ocean Engineers这是一篇开放获取的文章，根据创作共用署名非商业许可(http://creativecommons.org/licenses/by-nc/4.0)的条款分发，该许可允许在任何媒介上不受限制的非商业使用、分发和复制，前提是正确引用原创作品。
{"title":"Evaluation on Sensitivity and Approximate Modeling of Fire-Resistance Performance for A60 Class Deck Penetration Piece Using Heat-Transfer Analysis and Fire Test","authors":"W. Park, C. Song","doi":"10.26748/KSOE.2021.012","DOIUrl":"https://doi.org/10.26748/KSOE.2021.012","url":null,"abstract":"The A60 class deck penetration piece is a fire-resistance apparatus installed on the deck compartment to protect lives and to prevent flame diffusion in the case of a fire accident in a ship or offshore plant. In this study, the sensitivity of the fire-resistance performance and approximation characteristics for the A60 class penetration piece was evaluated by conducting a transient heat-transfer analysis and fire test. The transient heat-transfer analysis was conducted to evaluate the fire-resistance design of the A60 class deck penetration piece, and the analysis results were verified via the fire test. The penetration-piece length, diameter, material type, and insulation density were used as the design factors (DFs), and the output responses were the weight, temperature, cost, and productivity. The quantitative effects of each DF on the output responses were evaluated using the design-of-experiments method. Additionally, an optimum design case was identified to minimize the weight of the A60 class deck penetration piece while satisfying the allowable limits of the output responses. According to the design-of-experiments results, various approximate models, e.g., a Kriging model, the response surface method, and a radial basis function-based neural network (RBFN), were generated. The design-of-experiments results were verified by the approximation results. It was concluded that among the approximate models, the RBFN was able to explore the design space of the A60 class deck penetration piece with the highest accuracy. Received 18 February 2021, revised 5 March 2021, accepted 12 March 2021 Corresponding author Chang Yong Song: +82-61-450-2732, cysong@mokpo.ac.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131380223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to perform a precise wave tank experiment, it is necessary to maintain the incident wave generated by the wavemaker in a steady state and to effectively remove the reflected waves. In this paper, a combined sloping-wall-type punching plate wave absorber was proposed to attenuate reflected waves effectively in a two-dimensional mini wave tank. Using the four-point reflection separation method, the reflected waves were measured to determine the reflection coefficients. Experiments were conducted under various punching plate porosities, sloping plate angles, and incident wave conditions to evaluate the performance of the combined punching plate wave absorber. The most effective wave absorbing performance was achieved when the porosity was 10% and the inclination angle of the punching plate was 18.6° under the present condition. It was also found that the installation of the sloping plate could improve the wave attenuation performance by generating the shoaling effect of the incident wave. Received 14 February 2021, revised 8 March 2021, accepted 12 March 2021 Corresponding author Weoncheol Koo: +82-32-860-7348, wckoo@inha.ac.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
为了进行精确的波槽实验，必须使造波器产生的入射波保持稳定状态，并有效地去除反射波。本文提出了一种组合式斜壁冲孔板吸波器，可以有效地衰减二维微波槽中的反射波。采用四点反射分离法对反射波进行测量，确定反射系数。在不同的冲孔板孔隙率、倾斜板角度和入射波条件下，对组合冲孔板吸波器的性能进行了评价。在此条件下，孔隙率为10%，冲板倾角为18.6°时吸波效果最佳。斜板的安装可以通过产生入射波的浅滩效应来提高波的衰减性能。通讯作者Weoncheol Koo: +82-32-860-7348, wckoo@inha.ac.kr c 2021, The Korean Society of Ocean Engineers这是一篇开放获取的文章，根据创作共用署名非商业许可(http://creativecommons.org/licenses/by-nc/4.0)的条款发布，允许在任何媒介上不受限制的非商业使用、分发和复制，前提是原始作品被适当引用。
{"title":"An Experimental Study on Wave Absorber Performance of Combined Punching Plate in a Two-Dimensional Mini Wave Tank","authors":"H. Jung, W. Koo","doi":"10.26748/KSOE.2021.006","DOIUrl":"https://doi.org/10.26748/KSOE.2021.006","url":null,"abstract":"In order to perform a precise wave tank experiment, it is necessary to maintain the incident wave generated by the wavemaker in a steady state and to effectively remove the reflected waves. In this paper, a combined sloping-wall-type punching plate wave absorber was proposed to attenuate reflected waves effectively in a two-dimensional mini wave tank. Using the four-point reflection separation method, the reflected waves were measured to determine the reflection coefficients. Experiments were conducted under various punching plate porosities, sloping plate angles, and incident wave conditions to evaluate the performance of the combined punching plate wave absorber. The most effective wave absorbing performance was achieved when the porosity was 10% and the inclination angle of the punching plate was 18.6° under the present condition. It was also found that the installation of the sloping plate could improve the wave attenuation performance by generating the shoaling effect of the incident wave. Received 14 February 2021, revised 8 March 2021, accepted 12 March 2021 Corresponding author Weoncheol Koo: +82-32-860-7348, wckoo@inha.ac.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130785471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, a computational fluid dynamics (CFD) simulation based on an Eulerian-Eulerian approach was used to evaluate the mixing performance of a mud agitator through the distribution of bulk particles. Firstly, the commercial CFD software Star-CCM+ was verified by performing numerical simulations of single-phase water mixing problems in an agitator with various turbulence models, and the simulation results were compared with an experiment. The standard model was selected as an appropriate turbulence model, and a grid convergence test was performed. Then, a simulation of the liquid-solid multi-phase mixing in an agitator was simulated with different multi-phase interaction models, and lift and drag models were selected. In the case of the lift model, the results were not significantly affected, but Syamlal and O’Brien’s drag model showed more reasonable results with respect to the experiment. Finally, with the properly determined simulation conditions, a multi-phase flow simulation of a mud agitator was performed to predict the mixing time and spatial distribution of solid particles. The applicability of the CFD multi-phase simulation for the practical design of a mud agitator was confirmed. Received 1 February 2021, revised 3 March 2021, accepted 11 March 2021 Corresponding author Jong-Chun Park: +82-51-510-2480, jcpark@pnu.edu c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
本研究采用基于欧拉-欧拉方法的计算流体力学(CFD)模拟，通过散装颗粒的分布来评估泥浆搅拌器的混合性能。首先，利用商用CFD软件Star-CCM+对不同湍流模型的搅拌器内单相水混合问题进行了数值模拟，并与实验结果进行了比较。选择标准模型作为合适的湍流模型，并进行网格收敛试验。然后，采用不同的多相相互作用模型对搅拌器内液固混合过程进行了模拟，并选择了升力模型和阻力模型。升力模型对结果影响不明显，但Syamlal和O 'Brien的阻力模型相对于实验结果更为合理。最后，在确定适当的模拟条件下，对泥浆搅拌器进行多相流模拟，预测固体颗粒的混合时间和空间分布。验证了CFD多相模拟在泥浆搅拌器实际设计中的适用性。通讯作者Jong-Chun Park: +82-51-510-2480, jcpark@pnu.edu c 2021, The Korean Society of Ocean Engineers这是一篇开放获取的文章，根据创作共用归属非商业许可(http://creativecommons.org/licenses/by-nc/4.0)的条款分发，该许可允许在任何媒介上不受限制的非商业使用、分发和复制，前提是原始作品被适当引用。
{"title":"CFD Simulation of Multiphase Flow by Mud Agitator in Drilling Mud Mixing System","authors":"Tae-Young Kim, G. Jeon, Jong-Chun Park","doi":"10.26748/KSOE.2021.010","DOIUrl":"https://doi.org/10.26748/KSOE.2021.010","url":null,"abstract":"In this study, a computational fluid dynamics (CFD) simulation based on an Eulerian-Eulerian approach was used to evaluate the mixing performance of a mud agitator through the distribution of bulk particles. Firstly, the commercial CFD software Star-CCM+ was verified by performing numerical simulations of single-phase water mixing problems in an agitator with various turbulence models, and the simulation results were compared with an experiment. The standard model was selected as an appropriate turbulence model, and a grid convergence test was performed. Then, a simulation of the liquid-solid multi-phase mixing in an agitator was simulated with different multi-phase interaction models, and lift and drag models were selected. In the case of the lift model, the results were not significantly affected, but Syamlal and O’Brien’s drag model showed more reasonable results with respect to the experiment. Finally, with the properly determined simulation conditions, a multi-phase flow simulation of a mud agitator was performed to predict the mixing time and spatial distribution of solid particles. The applicability of the CFD multi-phase simulation for the practical design of a mud agitator was confirmed. Received 1 February 2021, revised 3 March 2021, accepted 11 March 2021 Corresponding author Jong-Chun Park: +82-51-510-2480, jcpark@pnu.edu c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134565167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The prediction of maneuverability is very important in the design process of an underwater vehicle. In this study, we predicted the steady turning ability of a symmetrical underwater vehicle while considering interactions between the yaw rate and drift/rudder angle through a simulation-based methodology. First, the hydrodynamic force and moment, including coupled derivatives, were obtained by computational fluid dynamics (CFD) simulations. The feasibility of CFD results were verified by comparing static drift/rudder simulations to vertical planar motion mechanism (VPMM) tests. Turning motion simulations were then performed by solving 2-degree-of-freedom (DOF) equations with CFD data. The turning radius, drift angle, advance, and tactical diameter were calculated. The results show good agreement with sea trial data and the effects on the turning characteristics of coupled interaction terms, especially between the yaw rate and drift angle. Received 15 November 2020, revised 7 March 2021, accepted 9 March 2021 Corresponding author Jeong-Hoon Park: +82-31-8026-4881, jeonghoon.park@lignex1.com c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
在水下航行器的设计过程中，机动性的预测是非常重要的。在这项研究中，我们通过基于仿真的方法，在考虑偏航率和漂移/舵角之间相互作用的情况下，预测了对称水下航行器的稳定转向能力。首先，通过计算流体动力学(CFD)模拟得到了流体动力和力矩及其耦合导数;通过将静态漂移/方向舵模拟与垂直平面运动机构(VPMM)试验进行对比，验证了CFD结果的可行性。然后利用CFD数据求解二自由度(DOF)方程进行转弯运动仿真。计算了转弯半径、漂移角、推进和战术直径。分析结果与海试数据吻合较好，并分析了横摆角速度和偏航角之间的耦合作用对飞机转向特性的影响。2020年11月15日收稿，2021年3月7日修订，2021年3月9日收稿。通讯作者Jeong-Hoon Park:+82-31-8026-4881, jeonghoon.park@lignex1.com c 2021，韩国海洋工程师学会这是一篇开放获取的文章，根据创作共用归属非商业许可(http://creativecommons.org/licenses/by-nc/4.0)的条款分发，该许可允许在任何媒介上不受限制的非商业使用、分发和复制，前提是正确引用原创作品。
{"title":"Simulation-Based Prediction of Steady Turning Ability of a Symmetrical Underwater Vehicle Considering Interactions Between Yaw Rate and Drift/Rudder Angle","authors":"Jeong-Hoon Park, M. Shin, Y. Jeon, Yeon-gyu Kim","doi":"10.26748/KSOE.2020.067","DOIUrl":"https://doi.org/10.26748/KSOE.2020.067","url":null,"abstract":"The prediction of maneuverability is very important in the design process of an underwater vehicle. In this study, we predicted the steady turning ability of a symmetrical underwater vehicle while considering interactions between the yaw rate and drift/rudder angle through a simulation-based methodology. First, the hydrodynamic force and moment, including coupled derivatives, were obtained by computational fluid dynamics (CFD) simulations. The feasibility of CFD results were verified by comparing static drift/rudder simulations to vertical planar motion mechanism (VPMM) tests. Turning motion simulations were then performed by solving 2-degree-of-freedom (DOF) equations with CFD data. The turning radius, drift angle, advance, and tactical diameter were calculated. The results show good agreement with sea trial data and the effects on the turning characteristics of coupled interaction terms, especially between the yaw rate and drift angle. Received 15 November 2020, revised 7 March 2021, accepted 9 March 2021 Corresponding author Jeong-Hoon Park: +82-31-8026-4881, jeonghoon.park@lignex1.com c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116470373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sungjun Jung, Jae-Sang Jung, Yong-Guk Lee, Byeongwon Park, S. Hwang, I. Park, Jin-ha Kim, I. Park
To ensure the international competitiveness of the domestic offshore plant industry, a consensus has been formed regarding the requirement for large offshore basins for performing offshore plant performance verification. Accordingly, the Korea Research Institute of Ships & Ocean Engineering has built the world's largest deep ocean engineering basin (DOEB). The purpose of this study is to evaluate the characteristics of velocity distribution under various conditions of the DOEB. An independent measuring jig is designed and manufactured to measure the current velocities of many locations within a short time. The measurement jig is a 15-m-high triangular-truss structure, and the measurement sensors can move 15 m vertically through an electric motor-wire device. The current speed is measured under various impeller revolutions per minute and locations of the DOEB using the jig. The spatial distribution characteristics of the current velocity in the DOEB and the performance of the current generator are analyzed. The maximum speed is 0.56 m/s in the center of the DOEB water surface, thereby confirming sufficient current velocity distribution uniformity for model testing. Received 11 September 2020, revised 4 February 2021, accepted 4 February 2021 Corresponding author Sungjun Jung: +82-51-604-7827, jungsj@kriso.re.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
为确保国内海上电站产业的国际竞争力，对大型海上电站性能验证的要求已形成共识。因此，韩国船舶海洋科学研究院建造了世界上最大的深海工程盆地(DOEB)。本研究的目的是评价不同条件下DOEB的速度分布特征。设计和制造了一个独立的测量夹具，可以在短时间内测量许多位置的电流速度。测量夹具为高15米的三角桁架结构，测量传感器可通过电机-线装置垂直移动15米。目前的速度是在不同的叶轮转速每分钟和DOEB的位置使用跳汰机测量。分析了DOEB内电流速度的空间分布特征和电流发生器的性能。在DOEB水面中心最大流速为0.56 m/s，从而确定了足够的流速分布均匀性，可以进行模型试验。通讯作者Sungjun Jung: +82-51-604-7827, jungsj@kriso.re.kr c 2021, The Korean Society of Ocean Engineers这是一篇开放获取的文章，根据创作共用归属非商业许可(http://creativecommons.org/licenses/by-nc/4.0)的条款发布，允许在任何媒介上不受限制的非商业使用、分发和复制，前提是正确引用原创作品。
{"title":"Current Measurement and Velocity Spatial Distribution of Deep Ocean Engineering Basin","authors":"Sungjun Jung, Jae-Sang Jung, Yong-Guk Lee, Byeongwon Park, S. Hwang, I. Park, Jin-ha Kim, I. Park","doi":"10.26748/KSOE.2020.053","DOIUrl":"https://doi.org/10.26748/KSOE.2020.053","url":null,"abstract":"To ensure the international competitiveness of the domestic offshore plant industry, a consensus has been formed regarding the requirement for large offshore basins for performing offshore plant performance verification. Accordingly, the Korea Research Institute of Ships & Ocean Engineering has built the world's largest deep ocean engineering basin (DOEB). The purpose of this study is to evaluate the characteristics of velocity distribution under various conditions of the DOEB. An independent measuring jig is designed and manufactured to measure the current velocities of many locations within a short time. The measurement jig is a 15-m-high triangular-truss structure, and the measurement sensors can move 15 m vertically through an electric motor-wire device. The current speed is measured under various impeller revolutions per minute and locations of the DOEB using the jig. The spatial distribution characteristics of the current velocity in the DOEB and the performance of the current generator are analyzed. The maximum speed is 0.56 m/s in the center of the DOEB water surface, thereby confirming sufficient current velocity distribution uniformity for model testing. Received 11 September 2020, revised 4 February 2021, accepted 4 February 2021 Corresponding author Sungjun Jung: +82-51-604-7827, jungsj@kriso.re.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129189813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: For the fatigue design of offshore structures, it is essential to understand and use the S-N curves specified in various industry standards and codes. This study compared the characteristics of the S-N curves for five major codes. The codes reviewed in this paper were DNV Classification Rules (DNV GL, 2016), ABS Classification Rules (ABS, 2003), British Standards (BSI, 2015), International Welding Association Standards (IIW, 2008), and European Standards (BSI, 2005). Types of stress, such as nominal stress, hot-spot stress, and effective notch stress, were analyzed according to the code. The basic shape of the S-N curve for each code was analyzed. A review of the survival probability of the basic design S-N curve for each code was performed. Finally, the impact on the conservatism of the design was analyzed by comparing the S-N curves of three grades D, E, and F by the five codes. The results presented in this paper are considered to be a good guideline for the fatigue design of offshore structures because the S-N curves of the five most-used codes were analyzed in depth.
{"title":"Comparison of Fatigue Provisions in Various Codes and Standards-Part 1: Basic Design S-N Curves of Non-Tubular Steel Members","authors":"S. Im, J. Choung","doi":"10.26748/KSOE.2021.001","DOIUrl":"https://doi.org/10.26748/KSOE.2021.001","url":null,"abstract":": For the fatigue design of offshore structures, it is essential to understand and use the S-N curves specified in various industry standards and codes. This study compared the characteristics of the S-N curves for five major codes. The codes reviewed in this paper were DNV Classification Rules (DNV GL, 2016), ABS Classification Rules (ABS, 2003), British Standards (BSI, 2015), International Welding Association Standards (IIW, 2008), and European Standards (BSI, 2005). Types of stress, such as nominal stress, hot-spot stress, and effective notch stress, were analyzed according to the code. The basic shape of the S-N curve for each code was analyzed. A review of the survival probability of the basic design S-N curve for each code was performed. Finally, the impact on the conservatism of the design was analyzed by comparing the S-N curves of three grades D, E, and F by the five codes. The results presented in this paper are considered to be a good guideline for the fatigue design of offshore structures because the S-N curves of the five most-used codes were analyzed in depth.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122428347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sunghoon Hong, Y. Jeong, Taeyoon Kim, V. M. Huynh, I. Kim, Jungmin Nam, D. Hur, Jooyong Lee, Soonchul Kwon
Artificial Coral Reefs (ACRs) have been introduced to help solve coastal erosion problems, but their feasibility has not been assessed with field data. This study conducted a feasibility analysis of ACRs on their erosion mitigation effects by performing a case study of Cheonjin-Bongpo beach, South Korea. A numerical-physical combined analysis was carried out using a SWAN model simulation and physical model test with a scale of 1/25 based on field observations of Cheonjin-Bongpo beach. Both Dean’s parameter and the surf-scaling parameter were applied to comparative analysis between the absence and presence conditions of the ACR. The results for this combined method indicate that ACR attenuates the wave height significantly (59~71%). Furthermore, ACR helps decrease the mass flux (~50%), undertow (~80%), and maximum wave set up (~61%). The decreases in Dean’s parameter (~66%) and the surf-scaling parameter suggest that the wave properties changed from the dissipative type to the reflective type even under high wave conditions. Consequently, an ACR can enhance shoreline stability. Received 12 November 2020, revised 1 December 2020, accepted 1 December 2020 Corresponding author Soonchul Kwon: +82-51-510-7640, sckwon@pusan.ac.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
人工珊瑚礁(ACRs)已被引入以帮助解决海岸侵蚀问题，但其可行性尚未得到实地数据的评估。本研究以韩国cheonjin - bong - po海滩为例，对ACRs减缓侵蚀效果进行可行性分析。采用SWAN模型模拟和1/25比例尺的物理模型试验，在天津-奉浦海滩野外观测基础上进行数值-物理结合分析。采用Dean’s参数和surf-scaling参数对ACR的存在和不存在情况进行了对比分析。结果表明，ACR对波高有明显的衰减作用(衰减幅度为59~71%)。此外，ACR还有助于减少质量通量(~50%)、底流(~80%)和最大波浪建立(~61%)。Dean’s参数和海浪标度参数的减小(~66%)表明，即使在高波条件下，波浪性质也从耗散型转变为反射型。因此，ACR可以增强海岸线的稳定性。通讯作者Soonchul Kwon: +82-51-510-7640, sckwon@pusan.ac.kr c 2021, The Korean Society of Ocean Engineers这是一篇开放获取的文章，根据创作共用归属非商业许可(http://creativecommons.org/licenses/by-nc/4.0)的条款分发，该许可允许在任何媒介上不受限制的非商业使用、分发和复制，前提是正确引用原创作品。
{"title":"Application of the Artificial Coral Reef as a Coastal Erosion Prevention Method with Numerical-Physical Combined Analysis (Case study: Cheonjin-Bongpo beach, Kangwon province, South Korea)","authors":"Sunghoon Hong, Y. Jeong, Taeyoon Kim, V. M. Huynh, I. Kim, Jungmin Nam, D. Hur, Jooyong Lee, Soonchul Kwon","doi":"10.26748/ksoe.2020.065","DOIUrl":"https://doi.org/10.26748/ksoe.2020.065","url":null,"abstract":"Artificial Coral Reefs (ACRs) have been introduced to help solve coastal erosion problems, but their feasibility has not been assessed with field data. This study conducted a feasibility analysis of ACRs on their erosion mitigation effects by performing a case study of Cheonjin-Bongpo beach, South Korea. A numerical-physical combined analysis was carried out using a SWAN model simulation and physical model test with a scale of 1/25 based on field observations of Cheonjin-Bongpo beach. Both Dean’s parameter and the surf-scaling parameter were applied to comparative analysis between the absence and presence conditions of the ACR. The results for this combined method indicate that ACR attenuates the wave height significantly (59~71%). Furthermore, ACR helps decrease the mass flux (~50%), undertow (~80%), and maximum wave set up (~61%). The decreases in Dean’s parameter (~66%) and the surf-scaling parameter suggest that the wave properties changed from the dissipative type to the reflective type even under high wave conditions. Consequently, an ACR can enhance shoreline stability. Received 12 November 2020, revised 1 December 2020, accepted 1 December 2020 Corresponding author Soonchul Kwon: +82-51-510-7640, sckwon@pusan.ac.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"139 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129881760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Shin, G. Lee, K. Jung, Hyun-Jung Park, I. Park, S. Suh
Slug flow is the most common multi-phase flow encountered in oil and gas industry. In this study, the hydrodynamic features of flow in pipes investigated numerically using computational fluid dynamic (CFD) simulations for the effect of slug flow on the vertical and bent pipeline. The compressible Reynold averaged Navier-Stokes (RANS) equation was used as the governing equation, with the volume of fluid (VOF) method to capture the outline of the bubble in a pipeline. The simulations were tested for the grid and time step convergence, and validated with the experimental and theoretical results for the main hydrodynamic characteristics of the Taylor bubble, i.e., bubble shape, terminal velocity of bubble, and the liquid film velocity. The slug flow was simulated with various air and water injection velocities in the pipeline. The simulations revealed the effect of slug flow as the pressure occurring in the wall of the pipeline. The peak pressure and pressure oscillations were observed, and those magnitudes and trends were compared with the change in air and water injection velocities. The mechanism of the peak pressures was studied in relation with the change in bubble length, and the maximum peak pressures were investigated for the different positions and velocities of the air and water in the pipeline. The pressure oscillations were investigated in comparison with the bubble length in the pipe and the oscillation was provided with the application of damping. The pressures were compared with the case of a bent pipe, and a 1.5 times higher pressures was observed due to the compression of the bubbles at the corner of the bent. These findings can be used as a basic data for further studies and designs on pipeline systems with multi-phase flow. Received 23 July 2020, revised 26 November 2020, accepted 2 December 2020 Corresponding author Kwang Hyo Jung: +82-51-510-2343, kjung@pusan.ac.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
段塞流是油气工业中最常见的多相流。本文采用计算流体动力学(CFD)方法对垂直和弯曲管道段塞流的影响进行了数值模拟。采用可压缩雷诺平均Navier-Stokes (RANS)方程作为控制方程，结合流体体积(VOF)方法捕捉管道中气泡的轮廓。仿真结果验证了网格收敛和时间步长收敛，并与实验和理论结果验证了泰勒气泡的主要水动力特性，即气泡形状、气泡末端速度和液膜速度。模拟了不同空气注入速度和注水速度下的段塞流。模拟结果揭示了段塞流对管道壁面压力的影响。观察了峰值压力和压力振荡，并将其大小和趋势与空气注入速度和注水速度的变化进行了比较。研究了峰值压力与气泡长度变化的关系，并对管道中空气和水在不同位置和速度下的最大峰值压力进行了研究。通过与管道内气泡长度的比较，研究了压力振荡，并在阻尼的作用下提供了振荡。将压力与弯曲管道的情况进行比较，由于弯曲管道角落的气泡被压缩，观察到的压力高出1.5倍。研究结果可为多相流管道系统的进一步研究和设计提供基础数据。通讯作者Kwang Hyo Jung: +82-51-510-2343, kjung@pusan.ac.kr c 2021, The Korean Society of Ocean Engineers这是一篇开放获取的文章，根据创作共用归属非商业许可(http://creativecommons.org/licenses/by-nc/4.0)的条款分发，允许在任何媒介上不受限制的非商业使用、分发和复制，前提是正确引用原创作品。
{"title":"Numerical Study on Taylor Bubble Rising in Pipes","authors":"S. Shin, G. Lee, K. Jung, Hyun-Jung Park, I. Park, S. Suh","doi":"10.26748/KSOE.2020.045","DOIUrl":"https://doi.org/10.26748/KSOE.2020.045","url":null,"abstract":"Slug flow is the most common multi-phase flow encountered in oil and gas industry. In this study, the hydrodynamic features of flow in pipes investigated numerically using computational fluid dynamic (CFD) simulations for the effect of slug flow on the vertical and bent pipeline. The compressible Reynold averaged Navier-Stokes (RANS) equation was used as the governing equation, with the volume of fluid (VOF) method to capture the outline of the bubble in a pipeline. The simulations were tested for the grid and time step convergence, and validated with the experimental and theoretical results for the main hydrodynamic characteristics of the Taylor bubble, i.e., bubble shape, terminal velocity of bubble, and the liquid film velocity. The slug flow was simulated with various air and water injection velocities in the pipeline. The simulations revealed the effect of slug flow as the pressure occurring in the wall of the pipeline. The peak pressure and pressure oscillations were observed, and those magnitudes and trends were compared with the change in air and water injection velocities. The mechanism of the peak pressures was studied in relation with the change in bubble length, and the maximum peak pressures were investigated for the different positions and velocities of the air and water in the pipeline. The pressure oscillations were investigated in comparison with the bubble length in the pipe and the oscillation was provided with the application of damping. The pressures were compared with the case of a bent pipe, and a 1.5 times higher pressures was observed due to the compression of the bubbles at the corner of the bent. These findings can be used as a basic data for further studies and designs on pipeline systems with multi-phase flow. Received 23 July 2020, revised 26 November 2020, accepted 2 December 2020 Corresponding author Kwang Hyo Jung: +82-51-510-2343, kjung@pusan.ac.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131010338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jangho Hong, Young-Shik Kim, H. Shim, Hee-Jin Kang, Yun-Ho Kim, Gyu Bum Kim, Seongpil Cho
As increasing the international community’s awareness of greenhouse gas reduction, the demand for eco-friendly ship fuel has accelerated recently. The fundamental aim of this study is to develop a new type of fully electrified ferry for passengers and cars considering Korean domestic coastal environmental conditions. Several technical difficulties are encountered in applying a fully electric propulsion system based on removable battery systems into a ship due to limitations imposed by the batteries’ size and capacity. This paper reviews and analyzes marine environment regulations strengthened recently, technology trends related to fully electric propulsion vessels in each country, and Korean domestic coastal environments. We propose a new fully electrified car ferry design with a displacement of 400 t applied in Korea. It is powered by removable battery systems pre-charged in a safe inland charging station. The mobile battery system is developed to enable roll-on and roll-off using wheels. The characteristics of the ship motion are analyzed based on the weight and location of the battery systems. We expect our battery systems to be applicable to larger ships in the future. Received 16 October 2020, revised 30 December 2020, accepted 30 December 2020 Corresponding author Young-Shik Kim: +82-42-866-3951, yskim@kriso.re.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
随着国际社会对温室气体减排意识的增强，最近对环保船用燃料的需求也在加速增长。此次研究的根本目的是考虑到韩国国内的沿海环境，开发一种新型的乘客和汽车全电气化渡轮。由于电池的尺寸和容量的限制，在将基于可拆卸电池系统的全电力推进系统应用于船舶时遇到了一些技术难题。本文对最近加强的海洋环境法规、各国全电力推进船的技术动向、韩国国内沿海环境进行了回顾和分析。我们建议在韩国应用排水量为400吨的全电动汽车渡轮。”它由可移动的电池系统供电，在一个安全的内陆充电站预充。移动电池系统的开发，使滚装和滚装使用车轮。基于电池系统的重量和位置，分析了船舶运动特性。我们希望我们的电池系统将来能应用于更大的船舶。通讯作者Young-Shik Kim: +82-42-866-3951, yskim@kriso.re.kr c 2021, The Korean Society of Ocean Engineers这是一篇开放获取的文章，根据创作共用署名非商业许可(http://creativecommons.org/licenses/by-nc/4.0)的条款分发，该许可允许在任何媒介上不受限制的非商业使用、分发和复制，前提是正确引用原创作品。
{"title":"Study on a Fully Electrified Car Ferry Design Powered by Removable Battery Systems Considering Domestic Coastal Environment","authors":"Jangho Hong, Young-Shik Kim, H. Shim, Hee-Jin Kang, Yun-Ho Kim, Gyu Bum Kim, Seongpil Cho","doi":"10.26748/KSOE.2020.061","DOIUrl":"https://doi.org/10.26748/KSOE.2020.061","url":null,"abstract":"As increasing the international community’s awareness of greenhouse gas reduction, the demand for eco-friendly ship fuel has accelerated recently. The fundamental aim of this study is to develop a new type of fully electrified ferry for passengers and cars considering Korean domestic coastal environmental conditions. Several technical difficulties are encountered in applying a fully electric propulsion system based on removable battery systems into a ship due to limitations imposed by the batteries’ size and capacity. This paper reviews and analyzes marine environment regulations strengthened recently, technology trends related to fully electric propulsion vessels in each country, and Korean domestic coastal environments. We propose a new fully electrified car ferry design with a displacement of 400 t applied in Korea. It is powered by removable battery systems pre-charged in a safe inland charging station. The mobile battery system is developed to enable roll-on and roll-off using wheels. The characteristics of the ship motion are analyzed based on the weight and location of the battery systems. We expect our battery systems to be applicable to larger ships in the future. Received 16 October 2020, revised 30 December 2020, accepted 30 December 2020 Corresponding author Young-Shik Kim: +82-42-866-3951, yskim@kriso.re.kr c 2021, The Korean Society of Ocean Engineers This is an open access article distributed under the terms of the creative commons attribution non-commercial license (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114796258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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