This study reviews the recent development and research results of a fixed oscillating water column (OWC) wave energy converter (WEC). The OWC WEC can be divided into fixed and floating types based on the installation location and movement of the structure. In this article, the study on a stationary OWC WEC, which is close to commercialization through the accumulation of long-term research achievements, is divided into five research categories with a focus on primary energy conversion research. These research categories include potential-flow-based numerical analysis, wave tank experiments, computational fluid dynamics analyses toward investigation of fluid viscous effects, U-shaped OWC studies that can amplify water surface displacement in the OWC chamber, and studies on OWC prototypes that have been installed and operated in real sea environments. This review will provide an overview of recent research on the stationary OWC WEC and basic information for further detailed studies on the OWC.
{"title":"Oscillating Water Column (OWC) Wave Energy Converter Part 1: Fixed OWC","authors":"H. Yang, H. Jung, W. Koo","doi":"10.26748/ksoe.2022.009","DOIUrl":"https://doi.org/10.26748/ksoe.2022.009","url":null,"abstract":"This study reviews the recent development and research results of a fixed oscillating water column (OWC) wave energy converter (WEC). The OWC WEC can be divided into fixed and floating types based on the installation location and movement of the structure. In this article, the study on a stationary OWC WEC, which is close to commercialization through the accumulation of long-term research achievements, is divided into five research categories with a focus on primary energy conversion research. These research categories include potential-flow-based numerical analysis, wave tank experiments, computational fluid dynamics analyses toward investigation of fluid viscous effects, U-shaped OWC studies that can amplify water surface displacement in the OWC chamber, and studies on OWC prototypes that have been installed and operated in real sea environments. This review will provide an overview of recent research on the stationary OWC WEC and basic information for further detailed studies on the OWC.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123827997","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}
Pub Date : 2022-08-31DOI: 10.26748/ksoe.2021.099c1
Wang-Geun Lee, Sang-Hyun Kim, Doojin Jung, Sooyeon Kwon
This research was funded and conducted under 「the Competency Development Program for Industry Specialists」 of the Korean Ministry of Trade, Industry and Energy (MOTIE), operated by Korean Institute for Advancement of Technology (KIAT). (No. P0012646, HRD program for Global Advanced Engineer Education Program for Future Ocean Structures) and Basic research project (No. 2020R1 F1A1071610) supported by the National Research Foundation with funding from the Ministry of Communications and CO2 (DFOC) reduction based on the real operation of medium-sized ships conducted with the funding of the Ministry of Trade, the Industry and Energy's “Medium Shipyard Innovation Growth Development Project” with the support of Technology Development (Project No.: 20007847), and research project of Inha University (Project No.: 62968).
{"title":"Corrigendum to: Change in Turning Ability According to the Side Fin Angle of a Ship Based on a Mathematical Model","authors":"Wang-Geun Lee, Sang-Hyun Kim, Doojin Jung, Sooyeon Kwon","doi":"10.26748/ksoe.2021.099c1","DOIUrl":"https://doi.org/10.26748/ksoe.2021.099c1","url":null,"abstract":"This research was funded and conducted under 「the Competency Development Program for Industry Specialists」 of the Korean Ministry of Trade, Industry and Energy (MOTIE), operated by Korean Institute for Advancement of Technology (KIAT). (No. P0012646, HRD program for Global Advanced Engineer Education Program for Future Ocean Structures) and Basic research project (No. 2020R1 F1A1071610) supported by the National Research Foundation with funding from the Ministry of Communications and CO2 (DFOC) reduction based on the real operation of medium-sized ships conducted with the funding of the Ministry of Trade, the Industry and Energy's “Medium Shipyard Innovation Growth Development Project” with the support of Technology Development (Project No.: 20007847), and research project of Inha University (Project No.: 62968).","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"59 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133391515","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}
Reinforced polyurethane foam (R-PUF), a material for liquefied natural gas cargo containment systems, is expected to have different mechanical properties depending on its stacking position of foaming as the glass fiber reinforcement of R-PUF sinks inside R-PUF under the influence of gravity. In addition, since R-PUF is not a homogeneous material, it is also expected that the coordinate direction within this material has a great correlation with the mechanical properties. So, this study was conducted to confirm this correlation with the one between the mechanical properties and the stacking position. In particular, in this study, R-PUF of 3 different densities (130, 170, and 210 kg/m3) was used, and tensile, compression, and shear tests of this material were performed under 5 temperatures. As a result of the tests, it was confirmed that the strength and modulus of elasticity of the material increased as the temperature decreased. Specifically, the strength and modulus of elasticity in the Z direction, which was the lamination direction, tended to be lower than those in the other directions. Finally, the strength and elastic modulus of different specimens of the material found at the bottom of their lamination compared to the specimens with these properties found at positions other than their lamination bottom were evaluated. Further analysis confirmed that as the temperature decreased, hardening of R-PUF occurred, indicating that the strength and modulus of elasticity increased. On the other hand, as the density of R-PUF increased, a sharp increase in strength and elastic modulus of R-PUF was observed.
{"title":"Assessment of Cryogenic Material Properties of R-PUF Used in the CCS of an LNG Carrier","authors":"Haoze Song","doi":"10.26748/ksoe.2022.023","DOIUrl":"https://doi.org/10.26748/ksoe.2022.023","url":null,"abstract":"Reinforced polyurethane foam (R-PUF), a material for liquefied natural gas cargo containment systems, is expected to have different mechanical properties depending on its stacking position of foaming as the glass fiber reinforcement of R-PUF sinks inside R-PUF under the influence of gravity. In addition, since R-PUF is not a homogeneous material, it is also expected that the coordinate direction within this material has a great correlation with the mechanical properties. So, this study was conducted to confirm this correlation with the one between the mechanical properties and the stacking position. In particular, in this study, R-PUF of 3 different densities (130, 170, and 210 kg/m3) was used, and tensile, compression, and shear tests of this material were performed under 5 temperatures. As a result of the tests, it was confirmed that the strength and modulus of elasticity of the material increased as the temperature decreased. Specifically, the strength and modulus of elasticity in the Z direction, which was the lamination direction, tended to be lower than those in the other directions. Finally, the strength and elastic modulus of different specimens of the material found at the bottom of their lamination compared to the specimens with these properties found at positions other than their lamination bottom were evaluated. Further analysis confirmed that as the temperature decreased, hardening of R-PUF occurred, indicating that the strength and modulus of elasticity increased. On the other hand, as the density of R-PUF increased, a sharp increase in strength and elastic modulus of R-PUF was observed.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123230893","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}
: Subsea power cables are subjected to various external loads induced by environmental and mechanical factors during manufacturing, shipping, and installation. Therefore, the prediction of the structural strength is essential. In this study, experimental and theoretical analyses were performed to investigate the axial stiffness of subsea power cables. A uniaxial tensile test of a 6.5 m three-core AC inter-array subsea power cable was carried out using a 10 MN hydraulic actuator. In addition, the resultant force was measured as a function of displacement. The theoretical model proposed by Witz and Tan (1992) was used to numerically predict the axial stiffness of the specimen. The Newton – Raphson method was employed to solve the governing equation in the theoretical analysis. A comparison of the experimental and theoretical results for axial stiffness revealed satisfactory agreement. In addition, the predicted axial stiffness was linear notwithstanding the nonlinear geometry of the subsea power cable or the nonlinearity of the governing equation. The feasibility of both experimental and theoretical framework for predicting the axial stiffness of subsea power cables was validated. Nevertheless, the need for further numerical study using the finite element method to validate the framework is acknowledged.
{"title":"Experimental and Theoretical Study on the Prediction of Axial Stiffness of Subsea Power Cables","authors":"Woongshik Nam, K. Chae, Young-Cheon Lim","doi":"10.26748/ksoe.2022.012","DOIUrl":"https://doi.org/10.26748/ksoe.2022.012","url":null,"abstract":": Subsea power cables are subjected to various external loads induced by environmental and mechanical factors during manufacturing, shipping, and installation. Therefore, the prediction of the structural strength is essential. In this study, experimental and theoretical analyses were performed to investigate the axial stiffness of subsea power cables. A uniaxial tensile test of a 6.5 m three-core AC inter-array subsea power cable was carried out using a 10 MN hydraulic actuator. In addition, the resultant force was measured as a function of displacement. The theoretical model proposed by Witz and Tan (1992) was used to numerically predict the axial stiffness of the specimen. The Newton – Raphson method was employed to solve the governing equation in the theoretical analysis. A comparison of the experimental and theoretical results for axial stiffness revealed satisfactory agreement. In addition, the predicted axial stiffness was linear notwithstanding the nonlinear geometry of the subsea power cable or the nonlinearity of the governing equation. The feasibility of both experimental and theoretical framework for predicting the axial stiffness of subsea power cables was validated. Nevertheless, the need for further numerical study using the finite element method to validate the framework is acknowledged.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121099464","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, numerical analysis and experiments were performed to analyze the viscous damping effect according to the shape of the chamber skirt of the breakwater-linked inclined oscillating water column wave energy converter. Experiments were conducted using a two-dimensional mini wave tank and verified by comparing the results of a CFD numerical analysis. Pointed and rounded skirts were modeled to compare the effect of viscous damping when incident waves enter the chamber, and the difference in the displacement of the water surface in the chamber was compared according to the wave period for the two skirt shapes. The wave elevation in the chamber in the rounded-skirt condition was larger than the pointed-skirt condition in all wave periods, which was approximately 47% greater at 0.9 s of the incident wave period. Therefore, extracting the maximum energy through the optimal orifice is possible while minimizing the energy attenuation in the rounded-skirt condition.
{"title":"A Study on the Viscous Damping Effect according to the Shape of the Inclined OWC Chamber Skirt","authors":"H. Jung, W. Koo","doi":"10.26748/ksoe.2022.010","DOIUrl":"https://doi.org/10.26748/ksoe.2022.010","url":null,"abstract":": In this study, numerical analysis and experiments were performed to analyze the viscous damping effect according to the shape of the chamber skirt of the breakwater-linked inclined oscillating water column wave energy converter. Experiments were conducted using a two-dimensional mini wave tank and verified by comparing the results of a CFD numerical analysis. Pointed and rounded skirts were modeled to compare the effect of viscous damping when incident waves enter the chamber, and the difference in the displacement of the water surface in the chamber was compared according to the wave period for the two skirt shapes. The wave elevation in the chamber in the rounded-skirt condition was larger than the pointed-skirt condition in all wave periods, which was approximately 47% greater at 0.9 s of the incident wave period. Therefore, extracting the maximum energy through the optimal orifice is possible while minimizing the energy attenuation in the rounded-skirt condition.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121750413","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}
Recently, an analysis method using machine learning for solving problems in coastal and ocean engineering has been highlighted. Machine learning models are effective modeling tools for predicting specific parameters by learning complex relationships based on a specified dataset. In coastal and ocean engineering, various studies have been conducted to predict dependent variables such as wave parameters, tides, storm surges, design parameters, and shoreline fluctuations. Herein, we introduce and describe the application trend of machine learning models in coastal and ocean engineering. Based on the results of various studies, machine learning models are an effective alternative to approaches involving data requirements, time-consuming fluid dynamics, and numerical models. In addition, machine learning can be successfully applied for solving various problems in coastal and ocean engineering. However, to achieve accurate predictions, model development should be conducted in addition to data preprocessing and cost calculation. Furthermore, applicability to various systems and quantifiable evaluations of uncertainty should be considered.
{"title":"Review on Applications of Machine Learning in Coastal and Ocean Engineering","authors":"Tae-Yoo Kim, Woo-Dong Lee","doi":"10.26748/ksoe.2022.007","DOIUrl":"https://doi.org/10.26748/ksoe.2022.007","url":null,"abstract":"Recently, an analysis method using machine learning for solving problems in coastal and ocean engineering has been highlighted. Machine learning models are effective modeling tools for predicting specific parameters by learning complex relationships based on a specified dataset. In coastal and ocean engineering, various studies have been conducted to predict dependent variables such as wave parameters, tides, storm surges, design parameters, and shoreline fluctuations. Herein, we introduce and describe the application trend of machine learning models in coastal and ocean engineering. Based on the results of various studies, machine learning models are an effective alternative to approaches involving data requirements, time-consuming fluid dynamics, and numerical models. In addition, machine learning can be successfully applied for solving various problems in coastal and ocean engineering. However, to achieve accurate predictions, model development should be conducted in addition to data preprocessing and cost calculation. Furthermore, applicability to various systems and quantifiable evaluations of uncertainty should be considered.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122647342","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}
Three-dimensional finite element analysis (3D-FEA) models have been used to evaluate the shock-resistance responses of various equipments, including armaments mounted on a warship caused by underwater explosion (UNDEX). This paper aims to check the possibility of using one-dimensional (1D) FEA models for the shock-resistance responses. A frigate was chosen for the evaluation of the shock-resistance responses by the UNDEX. The frigate was divided into the thirteen discrete segments along the length of the ship. The 1D Timoshenko beam elements were used to model the frigate. The explosive charge mass and the stand-off distance were determined based on the ship length and the keel shock factor (KSF), respectively. The UNDEX pressure fields were generated using the Geers-Hunter doubly asymptotic model. The pseudo-velocity shock response spectrum (PVSS) for the 1D-FEA model (1D-PVSS) was calculated using the acceleration history at a concerned equipment position where the digital recursive filtering algorithm was used. The 1D-PVSS was compared with the 3D-PVSS that was taken from a reference, and a relatively good agreement was found. In addition, the 1D-PVSS was compared with the design criteria specified by the German Federal Armed forces, which is called the BV043. The 1D-PVSS was proven to be relatively reasonable, reducing the computing cost dramatically.
{"title":"Shock-Resistance Responses of Frigate Equipments by Underwater Explosion","authors":"Hyunwoo Kim, J. Choung","doi":"10.26748/ksoe.2022.008","DOIUrl":"https://doi.org/10.26748/ksoe.2022.008","url":null,"abstract":"Three-dimensional finite element analysis (3D-FEA) models have been used to evaluate the shock-resistance responses of various equipments, including armaments mounted on a warship caused by underwater explosion (UNDEX). This paper aims to check the possibility of using one-dimensional (1D) FEA models for the shock-resistance responses. A frigate was chosen for the evaluation of the shock-resistance responses by the UNDEX. The frigate was divided into the thirteen discrete segments along the length of the ship. The 1D Timoshenko beam elements were used to model the frigate. The explosive charge mass and the stand-off distance were determined based on the ship length and the keel shock factor (KSF), respectively. The UNDEX pressure fields were generated using the Geers-Hunter doubly asymptotic model. The pseudo-velocity shock response spectrum (PVSS) for the 1D-FEA model (1D-PVSS) was calculated using the acceleration history at a concerned equipment position where the digital recursive filtering algorithm was used. The 1D-PVSS was compared with the 3D-PVSS that was taken from a reference, and a relatively good agreement was found. In addition, the 1D-PVSS was compared with the design criteria specified by the German Federal Armed forces, which is called the BV043. The 1D-PVSS was proven to be relatively reasonable, reducing the computing cost dramatically.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122885686","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 IMO has decided to proceed with the early introduction of EEDI Phase 3, a CO2 emission regulation to prevent global warming. Measures to reduce CO2 emissions for ships that can be applied immediately are required to achieve CO2 reduction. We set six different CO2 emission scenarios according to the type of ship and fuel, and designed a monoethanolamine-based CO2 capture process for ships using a rate-based model of Aspen Plus v10. The simulation model using Aspen Plus was validated using pilot plant operation data. A ship inevitably tilts during operation, and the performance of a tilted column decreases as its height increases. When configuring the conventional CO2 capture process, we considered that the required column heights were so high that performance degradation was unavoidable when the process was implemented on a ship. We applied a parallel column concept to lower the column height and to enable easy installation and operation on a ship. Simulations of the parallel column confirmed that the required column height was lowered to less than 3 TEU (7.8 m).
国际海事组织(IMO)决定尽早引入EEDI第三阶段，即防止全球变暖的二氧化碳排放法规。为了实现二氧化碳减排，需要立即采取措施减少船舶的二氧化碳排放。我们根据船舶和燃料的类型设置了六种不同的二氧化碳排放情景，并使用基于速率的Aspen Plus v10模型设计了一种基于单乙醇胺的船舶二氧化碳捕集工艺。使用Aspen Plus的模拟模型通过中试工厂的运行数据进行了验证。船舶在运行过程中不可避免地会发生倾斜，倾斜柱的性能随着高度的增加而降低。在配置传统的二氧化碳捕集工艺时，我们考虑到所需的柱高度非常高，当该工艺在船上实施时，性能下降是不可避免的。我们采用了平行柱的概念来降低柱的高度，并使其易于在船上安装和操作。平行柱的模拟结果证实，所需的柱高降低到小于3teu (7.8 m)。
{"title":"Onboard CO2 Capture Process Design using Rigorous Rate-based Model","authors":"J. Jung, Y. Seo","doi":"10.26748/ksoe.2022.006","DOIUrl":"https://doi.org/10.26748/ksoe.2022.006","url":null,"abstract":"The IMO has decided to proceed with the early introduction of EEDI Phase 3, a CO2 emission regulation to prevent global warming. Measures to reduce CO2 emissions for ships that can be applied immediately are required to achieve CO2 reduction. We set six different CO2 emission scenarios according to the type of ship and fuel, and designed a monoethanolamine-based CO2 capture process for ships using a rate-based model of Aspen Plus v10. The simulation model using Aspen Plus was validated using pilot plant operation data. A ship inevitably tilts during operation, and the performance of a tilted column decreases as its height increases. When configuring the conventional CO2 capture process, we considered that the required column heights were so high that performance degradation was unavoidable when the process was implemented on a ship. We applied a parallel column concept to lower the column height and to enable easy installation and operation on a ship. Simulations of the parallel column confirmed that the required column height was lowered to less than 3 TEU (7.8 m).","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124772451","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}
Thi Thanh Diep Nguyen, Ji Won Park, V. Nguyen, Hyeong-Kyu Yoon, Joseph Chul Jung, M. M. Lee
Moored floating platforms have great potential in ocean engineering applications because a mooring system is necessary to keep the platform in station, which is directly related to the operational efficiency and safety of the platform. This paper briefly introduces the technical and operational details of an optical sensor for measuring the tension of mooring lines of a moored platform in waves. In order to check the performance of optical sensors, an experiment with a moored floating platform in waves is carried out in the wave tank at Changwon National University. The experiment is performed in regular waves and irregular waves with a semi-submersible and triangle platform. The performance of the optical sensor is confirmed by comparing the results of the tension of the mooring lines by the optical sensor and tension gauges. The maximum tension of the mooring lines is estimated to investigate the mooring dynamics due to the effect of the wave direction and wavelength in the regular waves. The significant value of the tension of mooring lines in various wave directions is estimated in the case of irregular waves. The results show that the optical sensor is effective in measuring the tension of the mooring lines. Received 11 February 2022, revised 16 April 2022, accepted 22 May 2022 Corresponding author Hyeon Kyu Yoon: +82-55-213-3683, hkyoon@changwon.ac.kr This paper was presented on the subject of “Experimental Study on Application of Optical Sensor in Mooring Line of Moored Floating Platform in Waves” in the Proceedings of the 2021 KAOSTS Joint Conference. c 2022, 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.
{"title":"Experimental Study on Application of an Optical Sensor to Measure Mooring-Line Tension in Waves","authors":"Thi Thanh Diep Nguyen, Ji Won Park, V. Nguyen, Hyeong-Kyu Yoon, Joseph Chul Jung, M. M. Lee","doi":"10.26748/ksoe.2022.003","DOIUrl":"https://doi.org/10.26748/ksoe.2022.003","url":null,"abstract":"Moored floating platforms have great potential in ocean engineering applications because a mooring system is necessary to keep the platform in station, which is directly related to the operational efficiency and safety of the platform. This paper briefly introduces the technical and operational details of an optical sensor for measuring the tension of mooring lines of a moored platform in waves. In order to check the performance of optical sensors, an experiment with a moored floating platform in waves is carried out in the wave tank at Changwon National University. The experiment is performed in regular waves and irregular waves with a semi-submersible and triangle platform. The performance of the optical sensor is confirmed by comparing the results of the tension of the mooring lines by the optical sensor and tension gauges. The maximum tension of the mooring lines is estimated to investigate the mooring dynamics due to the effect of the wave direction and wavelength in the regular waves. The significant value of the tension of mooring lines in various wave directions is estimated in the case of irregular waves. The results show that the optical sensor is effective in measuring the tension of the mooring lines. Received 11 February 2022, revised 16 April 2022, accepted 22 May 2022 Corresponding author Hyeon Kyu Yoon: +82-55-213-3683, hkyoon@changwon.ac.kr This paper was presented on the subject of “Experimental Study on Application of Optical Sensor in Mooring Line of Moored Floating Platform in Waves” in the Proceedings of the 2021 KAOSTS Joint Conference. c 2022, 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":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128158713","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}
Hyungjoo Kang, G. Cho, Min-Gyu Kim, Munjik Lee, Ji-Hong Li, H. Kim, Hansol Lee, Gwonsoo Lee
: This study presents a mission management technique that is a key component of underwater docking system used to expand the operating range of autonomous underwater vehicle (AUV). We analyzed the docking scenario and AUV operating environment, defining the feasible initial area (FIA) level, event level, and global path (GP) command to improve the rate of docking success and AUV safety. Non-holonomic constraints, mounted sensor characteristic, AUV and mission state, and AUV behavior were considered. Using AUV and docking station, we conducted experiments on land and at sea. The first test was conducted on land to prevent loss and damage of the AUV and verify stability and interconnection with other algorithms; it performed well in normal and abnormal situations. Subsequently, we attempted to dock under the sea and verified its performance; it also worked well in a sea environment. In this study, we presented the mission management technique and showed its performance. We demonstrated AUV docking with this algorithm and verified that the rate of docking success was higher compared to those obtained in other studies.
{"title":"Mission Management Technique for Multi-sensor-based AUV Docking","authors":"Hyungjoo Kang, G. Cho, Min-Gyu Kim, Munjik Lee, Ji-Hong Li, H. Kim, Hansol Lee, Gwonsoo Lee","doi":"10.26748/ksoe.2022.001","DOIUrl":"https://doi.org/10.26748/ksoe.2022.001","url":null,"abstract":": This study presents a mission management technique that is a key component of underwater docking system used to expand the operating range of autonomous underwater vehicle (AUV). We analyzed the docking scenario and AUV operating environment, defining the feasible initial area (FIA) level, event level, and global path (GP) command to improve the rate of docking success and AUV safety. Non-holonomic constraints, mounted sensor characteristic, AUV and mission state, and AUV behavior were considered. Using AUV and docking station, we conducted experiments on land and at sea. The first test was conducted on land to prevent loss and damage of the AUV and verify stability and interconnection with other algorithms; it performed well in normal and abnormal situations. Subsequently, we attempted to dock under the sea and verified its performance; it also worked well in a sea environment. In this study, we presented the mission management technique and showed its performance. We demonstrated AUV docking with this algorithm and verified that the rate of docking success was higher compared to those obtained in other studies.","PeriodicalId":315103,"journal":{"name":"Journal of Ocean Engineering and Technology","volume":"89 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115598878","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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