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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
Editor in Chief :
Volume & Issues
Volume 20, Issue 6 - Dec 2006
Volume 20, Issue 5 - Oct 2006
Volume 20, Issue 4 - Aug 2006
Volume 20, Issue 3 - Jun 2006
Volume 20, Issue 2 - Apr 2006
Volume 20, Issue 1 - Feb 2006
Selecting the target year
The Effects of Microstructure in Austenitic 316L Stainless Steels on the Strength and Damping Capacity
SON DONG-WOOK ; LEE JONG-MOON ; KIM HYO-JONG ; NAM KI-WOO ; PARK KYU-SEOP ; KANG CHANG-YONG ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 1~6
The effects of microstructure on the damping capacity and tensile properties of 316L stainless steel were investigated. Increasing the degree of cold working, the volume fraction of
decreased after rising to maximum value at specific level of cold working, the volume fraction of d-martensite slowly increased and then dramatically increased from the point of decreasing
volume fraction. Increasing the degree of cold working, the behnvior of damping capacity is similar to that of the
. After the damping capacity showing the maximum value at about
of cold rolling, damping capacity was decreased with the volume fraction of
. Tensile strength was proportional to the volume fraction of d-martensite, and elongation steeply decreased in the range low volume fraction of a'-martensite, then slowly decreased in range the above
volume fraction of d-martensite. The damping capacity and elongation is strongly controlled by the volume fraction of
martensite with liner relationship. However, the effect of the volume fraction of d-martensite and austenite phase on the damping capacity was not observed. Tensile strength was governed by the volume fraction of d-martensite.
Compressive Strength Characteristics of Cement Mixing Lightweight Soil For Recycling of Dredged Soil in Nakdong River Estuary
KIM YUN-TAE ; KIM HONG-JOO ; KWON YONG-KYU ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 7~15
In this research, the behavior characteristics of cement mixing lightweight soil (CMLS) for recycling of dredged soil in the Nakdong River estuary are experimentally investigated. CMLS is composed of the dredged soil from Nakdong River estuary, cement, and air foam. For this purpose, uniaxial compression tests are carried out for artificially prepared specimens of CMLS, with various initial water contents, cement contents, and mixing ratio of dredged soils. The experimental results of CMLS indicated that the compressive strength is strongly influenced by the cement contents, rather than water contents and air foam. Compressive strength of CMLS increased with an increase in cement content, while it decreased with an increase in water content and air foam content. It was also found that the modulus of deformation E50 was in a range of 44 to 128 times greater than the value of uniaxial compressive strength, cured in 28 days.
Block Lifting Analysis to Examine the Cause of Cracking in the Hopper Top Plate
KIM SANG-IL ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 16~19
With the fast growth of the shipbuilding industry, the number of lifting lugs used every year has reached onehundred. This paper is aimed at examining the cause of cracking in the hopper top plate, due to block lifting. First of all, we have investigated the fracture surface in the occurrence position of the crack of the hopper top plate, using the scanning electron microscope. In this study, we have evaluated the structural strength for COT super block under present lifting conditions. For this purpose, the equivalent stresses have been calculated by linear elastic analysis, using the finite element program ABAQUS.
A Study on the Performance of the Ring-type Impulse Turbine for Wave Energy Conversion
HYUN BEOM-SOO ; MOON JAE-SEUNG ; HONG SEOK-WON ; KIM KI-SUP ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 20~25
This paper deals with the design and aerodynamic analysis of a so-called 'ring-type' impulse turbine for wave energy conversion. Numerical analysis was performed using the CFD cock, FLUENT. The main idea of the proposed turbine rotor was to minimize the adverse effect of tip clearance of the turbine blade; the design was borrowed from a ducted propeller with connected ring tip for special purpose marine vehicles. Results show that the efficiency increases up to
, depending on flaw coefficient, with the higher flaw coefficient yielding better efficiency. Decrease of input coefficient CA was the main reason for higher efficiency. Performance of ring-type rotor at various design parameters, as well as flaw conditions, was investigated, and the advantages and the disadvantages of the present impulse turbine were also discussed.
An Experimental Study of Spray Nozzle Desalination Facility
SHIN HYUN-KYOUNG ; JOO HYUN-TAE ; PARK MIN-HO ; PARK KYOUNG-MIN ; KIM JIN-YOUNG ; LIM JIN-YOUNG ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 26~31
Experimental research was undertaken to develop a domestic spray nozzle used on equipment for desalination. First, we made a test set-up in order to confirm nozzle efficiency of spray and distribution under different pressure conditions. Then, we found a maximum spray condition after verifying reliability of this facility. An optimum arrangement of the nozzle, based on the test result, was made using CATIA V5 and EXCEL.
A Study on the Initial Hull Form Development and Resistance Performance of a 45 Knots Class High-Speed Craft
KIM JU-NAM ; JEONG UH-CHEUL ; PARK JE-WOONG ; KIM DO-JUNG ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 32~36
The initial hull form of a 100 tan, 45 knot class high-speed craft is newly developed. The resistance performances are investigated using a model test at high speed in a circulating water channel. The effect of the initial trim is studied together. Wave patterns are observed to clarify the relationship between the resistance performance and the wave characteristics. It can be found that the initial trim plays a role in increasing the resistance performance above a certain velocity.
Development of a Wave Monitoring System Using a Marine Radar
PARK JUN-SOO ; PARK SEUNG-GEUN ; KWON SUN-HONG ; PARK GUN-IL ; CHOI JAE-WOONG ; KANG YUN-TAE ; HA MUN-KEUN ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 37~42
In the ocean engineering field, information about the ocean environment is important for planning, design, and operation, especially the wave information. High precision wave data is also important for considering environmental problems, like efficient operation of ships. For this purpose, many methods were considered in the past. However, an on-board directing wave measurement system has not been incorporated. The use of conventional marine radar Plane Position Indicator (PPI) images allows the estimation of wave information on a real-time basis, using both space and time information, regarding the evolution of ocean surface waves. In order to achieve data acquisition, the Radar Scan Converter (RSC) has been developed. Three-dimensional analysis was performed. The comparison of wave information derived from this system, and that of wave buoy, shows that this wave field detecting system can be a useful tool.
An Interacting Wave Profile of Three Trains of Gravity Waves on Finite Depth by Contraction Method
JANG TAEK-SOO ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 43~47
Superposition of three wave trains on finite depth is investigated. This paper is focused on how to improve the linear superposition of three waves. This was realized by introducing the scheme. The idea of the scheme is based on a fixed point approach. Application of the scheme to the superposition makes it possible to obtain a wave profile of wave-wave interaction. With the help of FFT, it was possible to analyze high-order nonlinear frequencies for three interacting Stokes' waves on finite depth.
Computations of Flows and Acoustic Wave Emitted from Moving Body by ALE Formulation in Finite Difference Lattice Boltzmann Model
KANG HO-KEUN ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 48~54
In this paper, flowfield and acoustic-field around moving bodies are simulated by the Arbitrary Lagrangian Eulerian (ALE) formulation in the finite difference lattice Boltzmann method. Some effects are checked by comparing flaw about a square cylinder in ALE formulation and that in the fixed coordinates, and both agree very well. Matching procedure between the moving grid and fixed grid is also considered. The applied method in which the both grids are connected through buffer region is shown to be superior to moving overlapped grid. Dipole-like emissions of sound wave from harmonically vibrating bodies in two- and three-dimensional cases are simulated.
The Prediction of Water Quality in Ulsan Area Using Material Cycle Model
SHIN BUM-SHICK ; KIM KYU-HAN ; PYUN CHONG-KUN ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 55~62
Recently, pollution by development in coastal areas is going from bad to worse. The Korean government is attempting to make policies that prevent water pollution, but it is still difficult to say whether such measures are lowering pollution to an acceptable level. More specifically, the general investigation that has been done in KOREA does not accurately reflect the actual conditions of pollution in coastal areas. An investigation that quantitatively assesses water quality management using rational prediction technology must be attempted, and the ecosystem model, which incorporates both the 3-dimensional hydrodynamic and material cycle models, is the only one with a broad enough scope to obtain accurate results. The hydrodynamic model, which includes advection and diffusion, accounts for the ever-changing flow and (quality) of water in coastal areas, while the material cycle model accounts for pollutants and components of decomposition as sources of the carbon, phosphorus, and nitrogen cycles. In this paper, we simulated the rates of dissolved oxygen (DO), chemical oxygen demand (COD), total nitrogen(T-N) and total-phosphorous(T-P) in Korea's Ulsan Area. Using the ecosystem model, we did simulations using a specific set of parameters and did comparative analysis to determine those most appropriate for the actual environmental characteristics of Ulsan Area. The simulation was successful, making it now possible to predict the likelihood of coastal construction projects causing ecological damage, such as eutrophication and red tide. Our model can also be used in the environmental impact assessment (EIA) of future development projects in the ocean.
Numerical Analysis for Wave Propagation with Vegetated Coastal Area
LEE SEONG-DAE ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 63~68
Recently, it has been widely recognized that coastal vegetations may have great value in supporting fisheries, protecting from wave attack, stabilizing the sea bed and maintaining good scenery. Hydrodynamic factors play a major role in the functions of water quality and ecosystems. However, the studies on physical and numerical process of wave propagation are few and far behind compared to those on the hydrodynamic roles of coastal vegetations. In general, Vegetation flourishing along the coastal areas attenuates the incident waves, through momentum exchange between stagnated water mass in the vegetated area and rapid mass in the un-vegetated area. This study develops a numerical model for describing the wave attenuation rate in the complex topography with the vegetation area. Based on the numerical results, the physical properties of the wave attenuation are examined under various wave, geometric and vegetation conditions. Through the comparisons of these results, the effects of the vegetation properties, wave properties and model parameters such ac the momentum exchange coefficient have been clarified.
Optimal Acoustic Search Path Planning Based on Genetic Algorithm in Discrete Path System
CHO JUNG-HONG ; KIM JUNG-HAE ; KIM JEA-SOO ; LIM JUN-SEOK ; KIM SEONG-IL ; KIM YOUNG-SUN ;
Journal of Ocean Engineering and Technology, volume 20, issue 1, 2006, Pages 69~76
The design of efficient search path to maximize the Cumulative Detection Probability(CDP) is mainly dependent on experience and intuition when searcher detect the target using SONAR in the ocean. Recently with the advance of modeling and simulation method, it has been possible to access the optimization problems more systematically. In this paper, a method for the optimal search path calculation is developed based on the combination of the genetic algorithm and the calculation algorithm for detection range. We consider the discrete system for search path, space, and time, and use the movement direction of the SONAR for the gene of the genetic algorithm. The developed algorithm, OASPP(Optimal Acoustic Search Path Planning), is shown to be effective, via a simulation, finding the optimal search path for the case when the intuitive solution exists. Also, OASPP is compared with other algorithms for the measure of efficiency to maximize CDP.