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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Ocean Engineering and Technology
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Journal DOI :
Korean Society of Ocean Engineers
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Volume & Issues
Volume 27, Issue 6 - Dec 2013
Volume 27, Issue 5 - Oct 2013
Volume 27, Issue 4 - Aug 2013
Volume 27, Issue 3 - Jun 2013
Volume 27, Issue 2 - Apr 2013
Volume 27, Issue 1 - Feb 2013
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Study on Simulation of Subsea Production System
Park, Ju Yong ; Jo, Hyo Jae ; Lee, Seung Jae ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 1~7
DOI : 10.5574/KSOE.2013.27.3.001
The purpose of this study was the implementation of a simulation for a subsea production system. This subsea production system is installed under environments with high pressure and low temperature. Most of the processes for oil and gas production occur in the subsea equipment. Therefore, an understanding and study of subsea production systems is very difficult because people cannot directly observe the processes occurring in the subsea production system. A simulation system can be a useful solution for this difficult problem. In this research, information models and a 3-D graphic model of the subsea equipment were built using the object-oriented technology and 3-D CAD. The entire system was implemented with the help of simulation software, 3-DVIA Virtools. The simulation system for the subsea production system was tested using several production process scenarios. The results of the tests showed that the simulation system is very useful for understanding a subsea production system and could be a good educational tool.
Development of Integrated Corrosion Monitoring and Control System
Yoo, Nam-Hyun ; Kim, Young-Hun ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 8~14
DOI : 10.5574/KSOE.2013.27.3.008
Although there are various factors that threaten the security of ships, one of the most harmful is corrosion. It is not easy to find corroding areas and the status of corrosion, even though corrosion causes serious problems such as submergence and marine pollution as a result of leaking oil and polluted water. To monitor the corrosion of ships, non-destructive inspection, weight loss coupons, electrical resistance, linear polarization resistance, zero resistance ammeter, and electrochemical impedance spectroscopy have been developed. However, these methods require much time to detect corrosion, and most are not appropriate for real time monitoring. Coating, sacrificial anode, and impressed current cathodic protection (ICCP) methods have been developed to control corrosion. The ICCP and sacrificial anode methods are the most popular ways to prevent ship corrosion. However, ICCP is only appropriate for the outside of a ship and cannot be used for complex structures such as ballast tanks because these are composed of many separate chambers. Sacrificial anodes have to be replaced periodically. This paper proposes an integrated corrosion monitoring and control system (ICMCS) that can detect corrosion in real time and is appropriate for complex structures such as ballast tanks. Because the system uses titanium for an anode, exhausted anodes do not need to be replaced.
Analysis of Ultimate Capacity of Plate Anchor on Loading Rate Capacity in Clay
Seo, Young-Kyo ; Ryu, Dong-Man ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 15~21
DOI : 10.5574/KSOE.2013.27.3.015
Anchors are primarily designed and constructed to resist outwardly directed loads imposed on the foundation of a structure. These outwardly directed loads are transmitted to the soil at a greater depth by the anchors. Buried anchors have been used for thousands of years to stabilize structures. Various types of earth anchors are now used for the uplift resistance of transmission towers, utility poles, submerged pipelines, and tunnels. Anchors are also used for the tieback resistance of earth-retaining structures, waterfront structures, at bends in pressure pipelines, and when it is necessary to control thermal stress. In this research, we analyzed the uplift behavior of plate anchors in clay using a laboratory experiment to estimate the uplift behavior of plate anchors under various conditions. To achieve the research purpose, the uplift resistance and displacement characteristics of plate anchors caused by the embedment ratio, plate diameter, and loading rate were studied, compared, and analyzed for various cases.
Image Analysis Module for AR-based Navigation Information Display
Lee, Jung-Min ; Lee, Kyung-Ho ; Kim, Dae-Seok ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 22~28
DOI : 10.5574/KSOE.2013.27.3.022
This paper suggests a navigation information display system that is based on augmented reality technology. A navigator always has to confirm the information from marine electronic navigation devices and then compare it with the view of targets outside the windows. This "head down" posture causes discomfort and sometimes near accidents such as collisions or missing objects, because he or she cannot keep an eye on the front view of the windows. Augmented reality can display both virtual and real information in a single display. Therefore, we attempted to adapt AR technology to assist navigators. To analyze the outside view of the bridge window, various computer image processing techniques are required because the sea surface has many noises that disturb computer image processing for object detection, such as waves, wakes, light reflection, and so on. In this study, we investigated an analysis module to extract navigational information from images that are captured by a CCTV camera, and we validated our prototype.
Study on Behavior of Slender Bodies in Waves
Lee, Seung Jae ; Kang, Donghoon ; Jo, Hyo Jae ; Shin, Da Rae ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 29~35
DOI : 10.5574/KSOE.2013.27.3.029
The exploration areas for maritime resources such as oil and natural gas have gradually moved to deep sea areas. It has become difficult to use existing fixed marine structures, which are very costly to build, because that have reached the uppermost economic limit. Therefore, floating marine structures and flexible marine structures are preferred. In particular, slender bodies such as risers and pipes are important parts of ocean depth marine structures. These slender bodies have more flexible structural characteristics in deep water areas because their overall length becomes longer and thediameter/length slenderness ratio gets smaller. In addition, the dynamic behavior of slender bodies becomes complicated as external forces such as tides and waves act on it directly. In this study, in order to solve these problems, we performed model tests in a 2-D wave basin using flexible slender bodies with different modulus of elasticity values. As a result, we compiled statistics and compared the behaviors of flexible slender bodies with respect to the effect of the modulus of elasticity. We expect that the results could be used as reference data for the design of structures with flexible elements.
Study on Effectiveness of Ocean Meteorological Variables through Sensitivity Analysis of Ship Infrared Signature
Cho, Yong-Jin ; Jung, Ho-Seok ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 36~42
DOI : 10.5574/KSOE.2013.27.3.036
According to a study on improving ship survivability, an IR signature represents the contrast radiance intensity between the radiation signature from a ship and the background signature. It was found from applying stealth techniques to the process of ship development that the IR signature is remarkably sensitive and dependent on the environment. In this study, marine climate data for the sea near the Korean Peninsula were collected, and the marine meteorological environment in Korean waters was defined. Based on this data, a study on the sensitivity of the IR signature of target objects was performed using analytical methods. The results of the research indicated that clouds have important effects on the infrared signature, but the velocity of the wind and the humidity have only slight effects on the IR signature. In addition, the air and seawater temperatures had hardly any effect on the IR signature, but it is judged that additional study is needed.
Estimation of Wave Loads Acting on Stationary Floating Body Using Viscous Numerical Wave Tank Technique
Kim, Kyung-Mi ; Heo, Jae-Kyung ; Jeong, Se-Min ; Park, Jong-Chun ; Kim, Wu-Joan ; Cho, Yong-Jin ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 43~52
DOI : 10.5574/KSOE.2013.27.3.043
In the present study, a flow analysis for estimating the wave loads acting on a stationary floating body inside a viscous numerical wave tank was performed using the commercial software FLUENT. The governing equations for the viscous and incompressible fluid motion were the continuity and Navier-Stokes equations, and a piston-type wavemaker was employed to reproduce wave environments. First, the optimal simulation conditions were derived through numerical tests for the wavemaker and wave absorber, and then the wave loads and wave run-up on a vertical truncated cylinder were estimated and compared with the experimental and other numerical results.
Study on Moonpool Resonance Effect on Motion of Modern Compact Drillship
Yang, Seung Ho ; Yang, Young Jun ; Lee, Sang Beom ; Do, Jitae ; Kwon, Sun Hong ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 53~60
DOI : 10.5574/KSOE.2013.27.3.053
A drillship is a representative floating offshore installation. The boom in oil and gas field development has dramatically increased the demands for drillships. Drillships have a moonpool in the center area of the ship for the purpose of drilling. This moonpool has an effect on the seakeeping performance of a drillship in the vicinity of the resonance frequency. Because of the moonpool, drillships act in different resonance modes, called the sloshing mode and piston mode. The objective of this study was to find the moonpool effect on the motion of a drillship through the motion analysis of a currently operating modern compact drillship. The predicted resonance frequencies based on Molin`s theoretical formula, Fukuda`s empirical formula, and BEM-based numerical analysis are compared. The accuracy of the predictions using the theoretical and empirical formulas is compared with the numerical analysis and evaluated. In the case of the piston mode, the difference between the resonance frequency from theoretical formula and the resonance frequency from the numerical analysis is analyzed. The resonance frequency formula for more a complex moonpool geometry such as a moonpool with a cofferdam is necessarily emphasized.
Finite Element Simulation of Elastic Waves for Detecting Defects and Deteriorations in Underwater Steel Plates
Woo, Jinho ; Na, Won-Bae ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 61~66
DOI : 10.5574/KSOE.2013.27.3.061
This paper presents the results of finite element simulations of elastic wave propagation in an underwater steel plate and the verification of a proposed method utilizing elastic wave-based damage detection. For the simulation and verification, we carried out the following procedures. First, three-dimensional finite element models were constructed using a general purpose finite element program. Second, two types of damages (mechanical defects and deteriorations) were applied to the underwater steel plate and three parameters (defect location, defect width, and depth) were considered to adjust the severity of the applied damages. Third, elastic waves were generated using the oblique incident method with a Gaussian tone burst, and the response signals were obtained at the receiving point for each defect or deterioration case. In addition, the received time domain signals were analyzed, particularly by measuring the magnitudes of the maximum amplitudes. Finally, the presence and severity of each type of damage were identified by the decreasing ratios of the maximum amplitudes. The results showed that the received signals for the models had the same global pattern with minor changes in the amplitudes and phases, and the decreasing ratio generally increased as the damage area increased. In addition, we found that the defect depth was more critical than the width in the decrease of the amplitude. This mainly occurred because the layout of the depth interfered with the elastic wave propagation in a more severe manner than the layout of the width. An inverse analysis showed that the proposed method is applicable for detecting mechanical defects and quantifying their severity.
Flow-Turbine Interaction CFD Analysis for Performance Evaluation of Vertical Axis Tidal Current Turbines (I)
Yi, Jin-Hak ; Oh, Sang-Ho ; Park, Jin-Soon ; Lee, Kwang-Soo ; Lee, Sang-Yeol ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 67~72
DOI : 10.5574/KSOE.2013.27.3.067
In this study, numerical analyses that considered the dynamic interaction effects between the flow and a turbine were carried out to investigate the power output performance of an H-type Darrieus turbine rotor, which is one of the representative lifting-type vertical-axis tidal-current turbines. For this purpose, a commercial CFD code, Star-CCM+, was utilized for an example three-bladed turbine with a rotor diameter of 3.5 m, a solidity of 0.13, and the blade shape of an NACA0020 airfoil, and the optimal tip speed ratio (TSR) and corresponding maximum power coefficient were evaluated through exhaustive simulations with different sets of flow speed and external torque conditions. The optimal TSR and maximum power coefficient were found to be approximately 1.84 and 48%, respectively. The torque and angular velocity pulsations were also investigated, and it was found that the pulsation ratios for the torque and angular velocity were gradually increased and decreased with an increase in TSR, respectively.
Flow-Turbine Interaction CFD Analysis for Performance Evaluation of Vertical Axis Tidal Current Turbines (II)
Yi, Jin-Hak ; Oh, Sang-Ho ; Park, Jin-Soon ; Lee, Kwang-Soo ; Lee, Sang-Yeol ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 73~78
DOI : 10.5574/KSOE.2013.27.3.073
CFD (computational fluid dynamics) analyses that considered the dynamic interaction effects between the flow and a turbine were performed to evaluate the power output characteristics of two representative vertical-axis tidal-current turbines: an H-type Darrieus turbine and Gorlov helical turbine (GHT). For this purpose, a commercial CFD code, Star-CCM+, was utilized, and the power output characteristic were investigated in relation to the scale ratio using the relation between the Reynolds number and the lift-to-drag ratio. It was found that the power coefficients were significantly reduced when the scaled model turbine was used, especially when the Reynolds number was lower than
. The power output characteristics of GHT in relation to the twisting angle were also investigated using a three-dimensional CFD analysis, and it was found that the power coefficient was maximized for the case of a Darrieus turbine, i.e., a twisting angle of
, and the torque pulsation ratio was minimized when the blade covered
for the case of a turbine with a twisting angle of
Electrochemical Evaluation of Corrosion Property of Welded Zone of Seawater Pipe by DC Shielded Metal Arc Welding with Types of Electrodes
Lee, Sung-Yul ; Lee, Kyu-Hwan ; Won, Chang-Uk ; Na, Shane ; Yoon, Young-Gon ; Lee, Myeong-Hoon ; Kim, Yun-Hae ; Moon, Kyung-Man ; Kim, Jin-Gyeong ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 79~84
DOI : 10.5574/KSOE.2013.27.3.079
The seawater pipes in the engine rooms of ships are surrounded by severely corrosive environments caused by fast flowing seawater containing chloride ions, high conductivity, etc. Therefore, it has been reported that seawater leakage often occurs at a seawater pipe because of local corrosion. In addition, the leakage area is usually welded using shielded metal arc welding with various electrodes. In this study, when seawater pipes were welded with four types of electrodes(E4311, E4301, E4313, and E4316), the difference between the corrosion resistance values in their welding zones was investigated using an electrochemical method. Although the corrosion potential of a weld metal zone welded with the E4316 electrode showed the lowest value compared to the other electrodes, its corrosion resistance exhibited the best value compared to the other electrodes. In addition, a heat affected zone welded with the E4316 electrode also appeared to have the best corrosion resistance among the electrodes. Furthermore, the corrosion resistance of the weld metal zone and heat affected zone exhibited relatively better properties than that of the base metal zone in all of the cases welded with the four types of electrodes. Furthermore, the hardness values of all the weld metal zones were higher than the base metal zone.
FTA of Leakage Path in Subsea X-mas Tree System
Yoo, Won-Woo ; Park, Min-Sun ; Yang, Young-Soon ; Ruy, Won-Sun ; Jang, Beom-Seon ;
Journal of Ocean Engineering and Technology, volume 27, issue 3, 2013, Pages 85~90
DOI : 10.5574/KSOE.2013.27.3.085
The growing need for energy (oil and gas) has led to offshore resource development. As a reflection of this trend, there have been many advances in the technologies used for the subsea production systems that make offshore resource development possible. As the technologies for subsea production systems continue to grow, a subsea X-mas tree, the core equipment in a subsea production system, is required to have more functions than before. Generally, these complex functions lead to a change in its configuration. Therefore, this paper investigates a change in a subsea X-mas tree system to enhance system understanding, and conducts a leakage path analysis of a subsea X-mas tree system. Utilizing the recent configuration of the subsea X-mas tree, an identification of the leakage path and a quantitative risk analysis for the leakage using an FTA (fault tree analysis) are conducted.