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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 14, Issue 4 - Nov 2000
Volume 14, Issue 3 - Aug 2000
Volume 14, Issue 2 - May 2000
Volume 14, Issue 1 - Feb 2000
Volume 3, Issue 1 - 00 2000
Selecting the target year
The Hydro-Environmental Characteristics of Port Facilities around the Sea of Cheju Island
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 1~10
In order to effective manage the construction, disaster prevention plan and the harbor tranquility control, meteorological and sea-state characteristics around Cheju Island have been analyzed. Using results and damage examples of the port facilities under severe sea conditions, a reasonable construction control plan considering the regional characteristics of the sea-state and winds was proposed. That is, in northern part of Cheju Island, the construction work is affected mainly by the winter storms, while the typhoon mainly affects the southern part port facilities during summer to Autumn. Considering their typical characteristics, it is strongly suggested that the main construction work should be carried out during April to July in the northern part, and it should be made during October to next July in the southern part of the island. A permeable TTP mounded breakwater was constructed to protect severe waves as a temporal structure under the long-term development plan in Sogipo port. The transmission characteristics of the structure was discussed using the experimental results. The results show that the transmission coefficient
is over 20% of incident waves, which cause many problems in the cargo handling in relation to harbor tranquility. In conclusion, this kind of permeable structure can be used only as a temporal structure for the disaster prevention under the construction process. It causes many problems in harbor tranquility if it is used as a permanent harbor structures.s.
On the Characteristics of the Water Quality Changes due to the Development Phases of Pusan Port
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 11~19
This study aims to examine the characteristics of the water quality variation in relation to the change of water exchange rate with respect to the development phases of the Pusan port. To clarify the characteristics, water exchange caused by the variations of coastline shape and water surface area was examined by the numerical experiments using the Lagrangian particle tracking model based on 2-D shallow water equation. As the results of numerical experiments, it was proved that the water exchange in the Pusan port was decreased mainly due to the port development and the breakwaters construction. During the port development phases from 1875 to 1998, 35% of the sea-space in the port had decreased to make hinterland spaces. This resulted in the loss of wet-land and coastline change as well as decrease of the water exchange rate at the sea side. The city population in that period had rapidly increased from several thousands to 4 millions, resulting in the large discharge of sewages into the port area. Under the these environmental conditions, it can be clearly said that the water quality in the Pusan port is sensitively affected by the discharge of urban sewages decrease of the water exchange rate in relation to port and urban developments. In the study, the temporal changes of water quality were discussed with respect to the port development phases. It was clear that the water quality wad controlled by the exchange rate change under the port development as well as the input impact into the port from the urbanized city area. To make clean sea of the Pusan port, it is suggested that the sewage control, the water exchange and coastline control should be systematically checked under the concept of eco-friendly development and environmental management.
Hydraulic and Numerical Modeling of Seawater Circulation of Semi-enclosed Bay with the Flow-control Structures
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 20~28
Using the hydraulic and numerical model of semi-enclosed bay (Chinhae Bay), the efficiencies of flow-control structures on the seawater-circulation in the inner bay were investigated. Expecially, this study was confirmed the effectiveness of the flow-control structures at the mouth and narrow channel of Chinhae Bay through the experiments. The system of flow-control structures could enhance the water exchange improvement appropriately. The results of this study can be used as the long-term and integrated environmental impact assessment model in the inner bay.
Hydroelastic Responses of a Very Large Floating Structure in Time Domain
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 29~34
This paper describes transient responses of a very floating structure subjected to dynamic load induced by waves. A time domain method is applied to the hydroelastic problems for this purpose. The method is based on source-dipole and FEM scheme and on Newmark
method to pursuit time step process taking advantage of memory effect. The present procedure is carried out to analyze hydroelastic responses in regular waves and impact responses due to dropping aircraft.
The visual Simulation of Fluid Flow with Free Surface in a Virtual Water Tank
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 35~40
SMAC method is, one of the numerical simulation techniques, modified from the original MAC for the time-dependent variation of fluid flows. The Navier-Stokes equation for incompressible time-dependent viscous flow is applied and, also marker particles which move with the fluid are used. Two-dimensional numerical computations of fluid flow are carried out in a virtual water tank. This paper has shown very well the movements of marker particles using SMAC method.
Numerical Evaluation of 2nd Derivatives of the Potential in the Panel method for the Unsteady Potential Flow Problem
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 41~45
In solving the unsteady potential flow problem of the ship in waves with the panel method, in general one can consider the basic flow as the free stream or double body solution. For the double body solution, the body boundary condition has the 2nd derivatives of the velocity potential. Low order panel methods are known to suffer from the significant error in the 2nd derivatives computed at the body surface. This paper analyzes the numerical error in the 2nd derivatives for a 2-D cylinder and a 3-D sphere problem, and an extrapolation method to obtain the correct derivatives on the body surface is suggested.
A Numerical Analysis of Regional Atmospheric Circulation with Large Scale Reclamation of Coastal Region
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 46~54
Three dimensional numerical experiments that included the land-use transformation by the large scale reclamation were used to investigate the mesoscale air flow over the coastal regions. In this paper the surface temperature of the inland was determined through the surface heat budget consideration with inclusion of a layer of vegetation. The vertical diffusion coefficients of momentum, heat and specific humidity in the constant flux layer were taken from the Mellor and Yamada(1975). It has shown that the resulting model is able to reproduce the air circulation in coastal regions, and the simulated characteristics agree with the known properties of this circulation. A series of numerical experiments were then carried out to investigate the diurnal response of the air flow to various types of surface inhomogeneities.
An Experimental Study on the Shoreline Change during Beach Process
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 55~60
This paper is descried the experimental results of beach process including storm surge and beach recovery. By testing different surge levels and durations, effects of these to shoreline change were evaluated. In addition of beach recovery were investigated experimentally. On the other hand, we proposed the method, which can be applicable to complex hydrograph such as storm surge by modifying equation proposed by Kriebel and Dean. Moreover, applicability of this method is verified by comparing computing result with experiments.
A Study on the Numerical Model for Predicting Depth of Replacement and Consolidation by Embankment on Weak Soil
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 61~65
The estimation of soil stabilization is of great importance concerning the construction of structures on weak soil. A typical model of soil stabilization is considered as replacement, which is based on ground at failure due to direct loading on weak soil. The calculation of the line of predicting settlement was carried out using RPL and DIKE programs. The DIKE program is showing a tendency to excel totally about this embankment of the seadike. Hereafter, This program will be contributed widely to the construction of offshore structures on weak soil.
An Experimental Study on Strength Development of Concrete Including Fly Ash
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 66~71
The main objectives of this study are to carried out in order to evaluate strength development of Fly Ash concrete containing various amounts of Fly Ash such as 0%, 10%, 20% and 30%. The experimental variables included in this test program consist of content of Fly Ash, concrete strength and chemical activation. As Fly Ash increases, air content, strength development of concrete and slump loss of normal strength concrete were gradually decreased. The inclusion of Na
increased the short-term strength of concrete that contains Fly Ash. In addition, the strength development of concrete that contains Fly Ash and Na
A Study on the Application of Soilcrete Cement for Improvement of marine Clay
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 72~77
In this paper, the effect of ground improvement and the countermeasure for the increase of strength in soft ground (wasted fill, marine clay) was studied through utilization of Soilcrete Cement as a material of ground improvement. Soil samples were obtained from
sanitary landfill to assess the applicability of the clay liner using Soilcrete Cement. Several laboratory tests were performed with the samples and skin corrosion tests of steel pipe covered with Soilcrete Cement were performed. As a result, Soilcrete Cement is considered to be applicable to the construction site and to be effective for the prevention of the corrosion of the steel pipe.
A Study of Fatigue Crack Threshold Characteristics in Pressure Vessel Steel at Low Temperature
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 78~83
In this study, CT specimens were prepared from AST SA516 Gr. 70 which was used for pressure vessel plates for room and low temperature service. And we got the following characteristics from fatigue crack growth test carried out in the environment of room and low temperature at 25
and in the range of stress ratio of 0.05, 0.3 by means of opening mode displacement. At the constant stress ratio, the threshold stress intensity factor range
in the early stage of fatigue crack growth (Region I) and stress intensity factor range
K in the stable of fatigue crack growth (Region II) were increased in proportion to descending temperature. It was assumed that the fatigue resistance characteristics and fracture strength at low temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region. The straight line slope relation of logarithm da/dN -
K in Region II, that is, the fatigue crack growth exponent m increased with descending temperature at the constant stress ratio. It was assumed that the fatigue crack growth rate da/dN is rapid in proportion to descending temperature in Region II and the cryogenic-brittleness greatly affect a material with decreasing temperature.
Combustion Emission Characteristics on the Effect of Secondary Air Injection in Model Gas Turbine Combustor
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 84~89
The purpose of this study is to investigate the combustion emission characteristics by the effect of secondary air injection and variation of the excess air ratio in combustion field of model gas turbine combustor. For this purpose, mean temperature, CO,
and HC concentrations were measured by changing excess air ratio and secondary air injection. As a result of this study, mean temperature was decreased and CO, HC emission increased by increasing the excess air ratio of secondary air. Therefore, this results showed the secondary air injection effected strongly on the flame structure and combustion emission characteristics.
Influence of Moisture Absorption on the Mechanical Properties in the Laminated Composites
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 90~99
This study has been investigated about the influence of moisture environment properties in the unidirectional and cross laminated carbon fiber/epoxy and glass fiber/epoxy composites. As a results, it was found that the weight gain of water increased with the immersion time and the mechanical properties were decreased with the weight gain of water. And it was also shown that the mechanical properties of carbon fiber/epoxy laminates were better than those of glass fiber/epoxy laminates. And a gap of the mechanical properties between the two kinds of laminates was increasing with the immersion time in distilled water of 80
. Mechanical properties which decreased by moisture absorption in the CF and GF reinforced laminates were recovered up to some extent by drying in oven at 80
for 10 days.
A Study on the Development of Information System for the Ship Survey to Support Port State Control
Journal of Ocean Engineering and Technology, volume 14, issue 3, 2000, Pages 100~105
Port State Control (PSC) is the inspection of foreign ships in national ports for the purpose of verifying that the condition of the ships and its equipments comply with the requirement of international conventions and the ship is manned and operated in compliance with applicable international laws. On the other hand, check items in PSC are nearly similar to periodical survey of Classification Societies, because they have the same background regarding safety and maritime pollution prevention. The purpose of this study is to develope computer-aided information system for ship inspection item which is useful for effective implementation of Port State Control. For this work, the status of PSC is reviewed, and the related scheme of ship survey system in Classification Societies is investigated. On these bases, a computer software integrated database system and object-oriented technique is developed. The developed system is expected helpful to establish and maintain an effective system of Port State Control.