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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Ocean Engineering and Technology
Journal Basic Information
Journal DOI :
Korean Society of Ocean Engineers
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Volume & Issues
Volume 16, Issue 6 - Dec 2002
Volume 16, Issue 5 - Oct 2002
Volume 16, Issue 4 - Aug 2002
Volume 16, Issue 3 - Jun 2002
Volume 16, Issue 2 - Apr 2002
Volume 16, Issue 1 - Feb 2002
Selecting the target year
A Study on the Integration GIS with Hydrodynamic Model
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 1~6
The integration of Geographic Information Systems (GIS) with the hydrodynamic model was conducted in order to revitalize the use of geographical information and to aid in the understanding of tidal circulation patterns. A 2D finite difference numerical model was used to simulate n tidal circulation in the Suyoung Bay in Busan, Korea. CIS, especially the ArcView S/W is used to input the data of the numerical model, and is also used for the visualization of model outputs on the ground in the loosely coupled method. In this paper, an electronic navigational chart (ENC), which provides more accurate information in the ocean and coastal areas than any other digital information, is used as a base map for this integration. With the help of GIS, the integration can support th understanding of oceanographic information.
Wave force Acting on the Artificial Rock installed on a Submerged Breakwater in a Regular Wave field
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 7~17
Recently, artificial rocks, instead of buoys, have been placed on the submerged breakwater to indicate its location. The accurate estimation of wave forces on these rocks is deemed necessary for their stability design. Characteristics of the wave force, however, are expected . to be very complicated because of the occurrence of breaking or post-breaking waves. In this regard, wave forces exerted on an artificial rock have been investigated in this paper. The maximum wave force has been found to strongly dependent on the location and shape of the artificial rock that is placed on the submerged breakwater. The plunging breaker occurs near the loading cram edge of a submerged breakwater, which cause impulsive breaking wave force on the rock. Using the Morison equation, with the velocity and acceleration at the front face of the artificial rock and varying water surface level, it is possible to estimate wave forces, even impulsive breaking wave forces, that are acting on the rock installed on a submerged breakwater. The vertical wave force is also found to depend, significantly, on the buoyant force.
Dynamic Characteristics of Cantilever Pipe Conveying Fluid with Moving Mass Considering Nozzle Angle
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 18~24
The vibrational system in this study consists of a cantilever pipe conveying fluid, the moving mass upon it, and an attached tip mass. The equation of motion is derived by using the Lagrange equation. The influences of the velocity and the velocities of fluid flow in the pipe have been studied on the dynamic behavior of a cantilever pipe using a numerical method. While the moving mass moves upon the cantilever pipe, the velocity of fluid flow and the nozzle angle increase; as a result, the tip displacement of the cantilever pipe, conveying fluid, is decreased. After the moving mass passes over the cantilever pipe, the tip displacement of the pipe is influenced by the potential energy of the cantilever pipe and the deflection of the pipe; the effect is the result of the moving mass and gravity. As the velocity of fluid flow and nozzle angle increases, the natural frequency of he system is decreased at the second mode and third mode, but it is increased at the first mode. As the moving mass increases, the natural frequency of the system is decreased at all modes.
A Study on Practical PMM Test Technique for Ship Maneuverability Using System Identification Method
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 25~31
A system identification method is introduced to increase the prediction accuracy of a ship's maneuverability in PMM test, analysis. To improve the accuracy of linear hydrodynamic coefficients, the analysis techniques of pure sway and yaw tests are developed, and confirmed. In the analysis of sway tests, accuracy to linear hydrodynamic coefficients depends on the frequency of sway motion. To obtain nonlinear hydrodynamic coefficients for large drift angles, a combined yaw test is introduced. Using this system identification method, runs of PMM test can be reduced while retaining sufficient accuracy, compared to the Fourier integration method. Through the comparisons with sea trial results and the Fourier integration method, the accuracy and efficiency of the newly proposed system identification method, based on least square method, has been validated.
Application of Mexican Hat Function to Wave Profile Detection
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 32~36
This paper presents the results of wave profile detection from video image using the Mexican hat function. The Mexican hat function has been extensively used in the field of signal processing to detect discontinuity in the images. The analysis was done on the numerical image and video images of waves that were taken in the small wave flume. The results show that the Mexican hat function is an excellent tool for wave profile detection.
A Study on Computing Pit Excavation Volume by Terrain Surface Approximation
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 37~43
The calculation of earthwork plays a major role in the plan or design phase of many civil engineering projects, such as seashore reclamation; and thus, it has become very important to improve upon its accuracy. There have been common drawbacks to earlier methods of ground profiling, such as dialing with sharp corners or the grid points of any tow straight lines. In this paper, we prepose an algorithm for finding a terrain surface using the natural boundary conditions and the both direction spline method, which interpolates the given three-dimensional data by using spline. As a result of this study, the algorithm of the proposed two methods to estimate pit excavation volume should provide a better accuracy than Spot height, Chambers, Chen, or Lin method. Also, the mathematical model mentioned offers maximum accuracy in estimating the volume of a pit excavation.
Behavior and Lateral Force of H-piles under lateral Soil Movement in Sand
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 44~48
In lateral ground flow, slope stability, and land slide problems, H-piles have often been used, on a horizontally deforming ground, to prevent the failure of mass of soil in a downward and outward movement of a slope. Here, theoretical equations are derived to estimate the lateral force, assuming that the Mohr-Coulomb's plastic states occur in the ground, just around H-piles. In this study, some model experiments were performed to check the lateral forces determined from theoretical equations, using several pile widths, heights and various interval ratios between H-piles for sand specimens. The solution of the theoretical equation, derived from previous studies, showed reasonable characteristics for constants of soil, as well as for the interval, widths, and heights of H-Pile.
Analysis of Free Forging of Cylindrical Billets by Using finite Element Method
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 49~54
The Finite Element Method is applied to the determination of the deformed bulge profile and strain distribution during upset forming of cylindrical billets. From the results of simulation, the bulging along the z-axis becomes more severe with increasing eight reduction, and with increasing friction at the die-material interface. The present method can be used for the simple prediction of the deformed shape and strain distribution in upset forging of cylindrical billets with dissimilar fictional conditions at the die-material interfaces.
A Study on the Delamination Growth in Composite Laminates Subjected to Low-Velocity Impact
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 55~59
Delamination means that cracking occurs on the interface layer between composite laminates. In this paper, to predict the delamination growth in composite laminates subjected to low-velocity impact, the unit load method was introduced, and an eighteen-node 3-D finite element analysis, based on assumed strain mixed formulation, was conducted. Strain energy release rate, necessary to determine the delamination growth, was calculated by using the virtual crack closure technique. The unit load method saves the computation time more than the re-meshing method. The virtual crack closure technique enables the strain energy release rate to be easily calculated, because information of the singular stress field near the crack tip is not required. Hence, the delamination growth in composite laminates that are subjected to low-velocity impact can be efficiently predicted using the above-mentioned methods.
Hardness and EDM Processing of MoSi
Intermetallics for High Temperature Ship Engine
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 60~64
This paper describes the machining characteristics of the MoSi
--based composites through the process of electric discharge drilling with various tubular electrodes. In addition to hardness characteristics, microstructures of Nb/MoSi
laminate composites were evaluated from the variation of fabricating conditions, such as preparation temperature, applied pressure, and pressure holding time. MoSi
-based composites have been developed in new materials for jet engines of supersonic-speed airplanes and gas turbines for high-temperature generators. These high performance engines may require new hard materials with high strength and high temperature-resistance. Also, with the exception of grinding, traditional machining methods are not applicable to these new materials. Electric discharge machining (EDM) is a thermal process that utilizes a spark discharge to melt a conductive material. The tool electrode is almost -unloaded, because there is n direct contact between the tool electrode and the work piece. By combining a non-conducting ceramic with more conducting ceramic, it was possible to raise the electrical conductivity. From experimental results, it was found that the lamination from Nb sheet and MoSi
powder was an excellent strategy to improve hardness characteristics of monolithic MoSi
. However, interfacial reaction products, like (Nb, Mo)SiO
formed at the interface of Nb/MoSi
, and increased with fabricating temperature. MoSi
composites, with which a hole drilling was not possible through the conventional machining process, enhanced the capacity of ED-drilling by adding MbSi
, relative to that of SiC or ZrO
Mechanical Design of Deepwater Pipeline Wall Thickness Using the Recent Rules
Han-Suk Choi ;
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 65~70
This paper presents a mechanical design of the deepwater pipeline wall thickness using the recent design rules. Characteristics and limitations of the new codes were identified through a case study design in the Gulf of Mexico. In addition to the ASME, API, and DVD codes, the code of federal regulations (CFR) was also utilized in the design. It was found that conservatism still exists within the collapse prediction for water depth greater than 1500m. Comparision of the results from DNV and API codes were presented.
A Study on the Principal Performance of Purse Seiner Ship in 2 Vessels Formation
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 71~75
In this paper, a study on the principal performance of the purse seiner ship in two vessel formations was conducted. For this task, the outline of the purse seiner fishing system in two vessel formations was reviewed. At the same time, based on the general arrangement plan, hull from of the main vessel was developed. And the stability and ship motion characteristics of the ship design were estimated. Finally, to verify the characteristics of the resistance and self-propulsion coefficient, a model test in a circulating water channel was performed. As n result, it is anticipated that this presentation will be used as the foundation material for research of purse seiner.
A Study on the Optimum Formation of Fleet in Purse Seiner Fishing System
Journal of Ocean Engineering and Technology, volume 16, issue 6, 2002, Pages 76~81
The purpose of this study is to set up the optimum economical formation of the purse seiner fishing system. For this task, the characteristics of existing purse-seiner fishing system were reviewed, and the possible formations of the fleet in tile purse-seiner fishing system were examined through the reallocation of function for each individual vessel. In addition, economic evaluations of the possible formations of the fleet are carried out. Consequently, it was found that 2-vessel formations have the most economic efficiency. Then, a conceptual system design for the main vessel in the 2-vessel formations was performed. As a result, this paper can be used as a helpful guideline to develop the most profitable and economical fishing system in the fleet type fishery.