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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Ocean Engineering and Technology
Journal Basic Information
Journal DOI :
Korean Society of Ocean Engineers
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Volume & Issues
Volume 24, Issue 6 - Dec 2010
Volume 24, Issue 5 - Oct 2010
Volume 24, Issue 4 - Aug 2010
Volume 24, Issue 3 - Jun 2010
Volume 24, Issue 2 - Apr 2010
Volume 24, Issue 1 - Feb 2010
Selecting the target year
Structural Characteristics of Damaged Offshore Tubular Members
Cho, Sang-Rai ; Kwon, Jong-Sig ; Kwak, Dong-Il ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 1~7
Over the past few decades various experimental and theoretical investigations have been performed on offshore tubular members with regard to damage resistance and residual strength. Analysis of damaged tubular members requires a three-dimensional shell analysis for accurate results. Even though various commercial packages are available for this purpose, a beam-column analysis is preferred for offshore structural designs. In this paper, empirical equations are provided for a more accurate beam-column analysis of damaged tubes including the relationships between the lateral denting load and the depth of the dent, the rate of dent deepening due to increasing curvature and the longitudinal variation in the dent depth of damaged tubes. A design equation to predict the ultimate bending capacities of damaged offshore tubular members is also presented.
Performance of a Horizontal-axis Turbine Based on the Direction of Current Flow
Jo, Chul-Hee ; Park, Ro-Sik ; Yim, Jin-Young ; Lee, Kang-Hee ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 8~12
The use of a tidal-current power system is one source of renewable energy that can minimize the environmental impact of power production and offer many other advantages compared to conventional energy sources. Unlike other energy production approaches, rate of energy production can be precisely predicted and the operational rate is very high. The performance of the rotor, which has a vital role in energy production using tidal currents, is determined by various design factors, and it should be optimized for the specific ocean environment in the field. The horizontal-axis turbine is very sensitive to the direction of flow, and flow direction changes due to rise and fall of the tides. To investigate the performance of the rotor considering the interaction problems with incidence angle of flow, a series of experiments were conducted, and a 3D CFD model was designed and analyzed by ANSYS CFX. The results and findings are summarized in the paper.
Stability Evaluation during Transportation of Caisson for Breakwater
Seok, Jun ; Park, Jong-Chun ; Heo, Jae-Kyung ; Kang, Heon-Yong ; Bae, Yoon-Hyeok ; Kim, Moo-Hyun ; Kang, Yoon-Koo ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 13~22
While a caisson used for breakwater is carried by a floating dock, accompanying stability problem by its existing motions in the dock is quite important and should be pre-checked against sea environmental condition. In the stability analysis, the acceleration, velocity, angle of roll and pitch motions are important to calculate frictional force and separation force. If separation force becomes bigger than frictional force, serious collision may be occurred between caisson and floating dock. In this study, stability evaluation during the transportation of a caisson on floating dock for breakwater was performed by using a commercial program, HydroD and CHARM3D/HARP.
Numerical Study on the Enhancement of the Resistant Performance of ROV
Seo, Jang-Hoon ; Jeon, Chung-Ho ; Yoon, Hyun-Sik ; Chun, Ho-Hwan ; Kim, Su-Ho ; Kim, Tae-Hyung ; Woo, Jong-Sik ; Joo, Young-Sock ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 23~31
The flow around a remotely-operated vehicle (ROV) has been investigated numerically to improve the resistant performance by modifying the hull form of the ROV. In the case of the base hull form considered in this study, form drag rather than friction drag was the dominant component of total drag. Subsequently, the surfaces that were most susceptible to local pressure effects were modified to give them a more streamlined shape. Eleven different hull forms were chosen to undergo surface modification for drag reduction. In addition, four different boat-tail appendages with different slant angles were installed at the stern to reduce the wake vortices that are induced by the local regions of very low pressure. Consequently, a total of 11 different hull forms for drag reduction were considered. The final hull form, which combined the hull for which surface modification resulted in the lowest drag with a boat-tail appendage with a 15-degree slant angle, resulted in a drag reduction of 20%.
Effect of Surrounding Soil Properties on the Attenuation of the First Guided Longitudinal Wave Mode Propagating in Water-filled, Buried Pipes
Lee, Ju-Won ; Na, Won-Bae ; Shin, Sung-Woo ; Kim, Jae-Min ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 32~37
This study presents the attenuation characteristics of the first guided longitudinal wave mode propagating in water-filled, buried steel pipes in order to investigate the effects of soil saturation and compaction on the attenuation patterns. For numerical calculation of attenuation, 10 different combinations of S-wave velocity, P-wave velocity, and soil densities were considered. From the attenuation dispersion curves, which were obtained using Disperse software, we determined that the attenuation decreases as saturation increases, whereas it increases as compaction increases. Over the frequency range from 0.2 to 0.4 MHz, the first longitudinal wave mode has attenuations that are relatively lower than for other ranges, is faster than the first flexural wave mode, and is sensitive to defects aligned in the axial direction. Hence, the first longitudinal wave mode over the mentioned frequency range would be the proper choice for long-range buried pipelines that transport water.
Analysis of Weld Beads for Wall Thinning Defects in the Weld Zone of the Boost Pump Recirculation Pipe for Power Plants and Evaluation of Their Integrity
Nam, Ki-Woo ; Ahn, Seok-Hwan ; Do, Jae-Yoon ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 38~46
The wall thinning phenomenon of pipes was simulated as metal loss due to erosion and corrosion. Such wall thinning defects in the pipes of power plants are a very important safety consideration. In this study, we analyzed wall thinning defects that occurred by weld bead of weld zone of boost pump recirculation pipe. From the results of the analysis of pipe failures, numerical analysis was performed by Fluent v6.3.26 using the standard k-
model of the weld bead shape, such as an elliptical or a spherical shape, on the inner wall of the pipe. Using the results obtained, we showed the overlap effect by cavitations corrosion and erosion-corrosion at the bottom of the wall-thinning defect.
A Study of the Characteristics of Various Board Shapes for Use in the Development of Public Windsurfing Equipment
Im, Jang-Gon ; Suh, Sung-Bu ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 47~52
In this paper, the shapes of windsurfing boards are proposed for the promotion of their public utilization. Initially, we investigated the principal dimensions of 1,500 windsurfing boards that were produced in the last six years to categorize the characteristics of the boards. Then, model tests were performed in a circulating water channel to determine the resistance characteristics and the flow phenomena, including the wetness of the decks. After analyzing the principal dimensions and the results of the tests of existing windsurfing boards, we proposed four public board shapes that resulted from changing the shapes of the nose and rail and protecting the deck of free-ride boards from wetness. Finally, we predicted the performance of the four proposed windsurfing boards.
A Study of the Design for the Topside Module Support Structure of an Offshore Floater
Song, Myung-Keun ; Jang, Beom-Seon ; Ko, Dae-Eun ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 53~58
Offshore floater such as FPSO, drillship is composed of topside and hull side, and the interface structure is called topside module support. In this study, practical considerations were investigated for the design of topside module supports, from the concept design stage to the final stage of structural determination, in view of design efficiency and construction productivity. The effects of welding design factors of topside module support, such as welding throat thickness, sectional welding area, and welding man-hours, were compared and analyzed closely with respect to productivity. The current status and problems regarding the application of deep or full penetration welding are discussed, and a direct-calculation method is suggested as a possible solution to these problems.
A Study on the Hull Form Design of Semi-Planing Round-Bilge Craft
Lee, Jung-Gwan ; Jung, Kwang-Hyo ; Suh, Sung-Bu ; Chun, Ho-Hwan ; Lee, In-Won ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 59~65
This study presents the design procedure for optimizing the semi-planing hull form, including appendages, using numerical and experimental methods. Four different referenced semi-planing hull forms were compared to determine their hydrodynamic performances, and one of the hull forms was modified for optimum operation at high-speed conditions (0.4 <
< 0.9). The optimized, semi-planing hull form was tested in the towing tank to investigate its resistance characteristics. Also, the results of the model tests with differing design parameters were used to choose the stern wedge and the spray strip to improve the hydrodynamic performance at high speeds.
Development of Internet-Based Marine Propeller Design and Analysis System
Jang, Hyun-Gil ; Ahn, Byoung-Kwon ; Moon, Il-Sung ; Lee, Chang-Sup ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 66~71
Numerical prediction of propeller performance plays an important role in a marine propeller design process. Program developers are consistently trying to improve diminish predicted errors, and program users need to keep up with the latest ones with minimum expenditure of time and money. We have developed an internet based design system in which clients can design propellers with remote access. In this paper, optimized Internet based Propeller Design and Analysis System (iProDAS) for transferences of the massive data is presented, and a sample design using iProDAS is examined.
A Study of the Shaft Power Measuring System Using Cameras
Jeong, Jeong-Soon ; Kim, Young-Bok ; Choi, Myung-Soo ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 72~77
This paper presents a method for measuring the shaft power of a marine main engine. Usually, in traditional systems for measuring shaft power, a strain gauge is used even though it has several disadvantages. First, it is difficult to set up the strain gauge on the shaft and acquire the correct signal for analysis. Second, it is very expensive and complicated. For these reasons, we investigated alternative approaches for measuring shaft power and proposed a new method that uses a vision-based measurement system. For this study, templates for image processing and CCD cameras were installed at the both ends of the shaft. Then, in order for the cameras to capture the images synchronously, we used a trigger mark and a optical sensor. The position of each template between the first and the second camera images were compared to calculate the torsion angle. The proposed measurement system can be installed more easily than traditional measurement systems and is suitable for any shaft because it does not contact the shaft. With this approach, it is possible to measure the shaft power while a ship is operating.
Investigation of Reducing Characteristics for the Spreading of Dredging Soil and the Diffusion of Contaminant by Silt Protector Curtain through Three Dimensional Numerical Model Experiment
Hong, Nam-Seeg ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 78~85
This study investigates reducing characteristics for the spreading of dredged soil and the diffusion of contaminant by silt protector curtain through three dimensional numerical experiment. The numerical medel is modified by combining the sediment transport characteristics for cohesive sediment into the previously developed model. Several numerical experiments have been given in order to investigate the reducing effect of silt protector using two dimensional numerical channel model under various parameters such as upstream flow velocity, depth of silt curtain and the position of dumped materials. Through the evaluation of several simulation results, we knew that the careful design has to be given in the determination of depth and position of silt protector.
RFID Applications from 2005 to 2010
Sheen, Dong-Mok ; Choi, Sung-Hee ; Lee, Gong-Seop ;
Journal of Ocean Engineering and Technology, volume 24, issue 4, 2010, Pages 86~93
RFID has been used as an identification tool that substitutes for bar codes. Its areas of application are increasing due to its suitability in ubiquitous environment. In this paper, first, we review various aspects of RFID, including standards, characteristics, and relationships with wireless sensor networks. Then, we review the technical aspects of RFID and its areas of application, e.g., supply chain management (SCM) and manufacturing since 2005. SCM, in which RFIDs can shorten lead time and ensure the quality of products, is one of the most active application areas. Manufacturing is a relatively new area for RFID applications, but it is believed that it can enhance the productivity and the reliability of the products. Also, the authors suggest research issues and limitations of RFID, as well as possible application areas related to marine engineering.