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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Society of Coastal and Ocean Engineers
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Journal DOI :
Korean Society of Coastal and Ocean Engineers
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Volume & Issues
Volume 22, Issue 6 - Dec 2010
Volume 22, Issue 5 - Oct 2010
Volume 22, Issue 4 - Aug 2010
Volume 22, Issue 3 - Jun 2010
Volume 22, Issue 2 - Apr 2010
Volume 22, Issue 1 - Feb 2010
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Estimation of Tidal Residual Flow and Its Variability in Kyunggi Bay of Korea
Kim, Chang-S. ; Lim, H.S. ; Kim, Jin-Ah ; Kim, Seon-Jeong ; Park, K.S. ; Jung, K.T. ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 22, issue 6, 2010, Pages 353~360
The Kyunggi Bay in mid-west of Korea is a relatively large estuarine system that connects the Han River system with Yellow Sea. Due to macro-tidal range of more than 8 m, the urban estuary shows deep tidal channels and wide tidal flats. Since last 30 years, the coastal development is undergoing, yielding noticeable change in environment. Particularly the tidal flat dynamics are generally accepted as being related with tidal residual flows in this area (Kim et al., 2009). We have estimated the annual variation and vertical structure of residual currents with one-year long observed flows in two major tidal channels of Kyunggi Bay. The moving average method and tidal current harmonic analysis yield nearly the same results on residual flow. The residual flow in Jangbong channel ranges from 20 cm/s in summer to 30 cm/s in winter. It is noticeable that the residual flow in Jangbong channel is flood dominant throughout the year, while the flow in Seokmo channel is ebb-dominant residual flow with current speed range of 20-40 cm/s. Due to the baroclinic response of relatively shallow estuary, significant reduction of energy in bottom layers have been observed, indicating the importance of residual circulation to the tidal flat behavior.
A Study of Storm Surges Characteristics on the Korean Coast Using Tide/Storm Surges Prediction Model and Tidal Elevation Data of Tidal Stations
You, Sung-Hyup ; Lee, Woo-Jeong ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 22, issue 6, 2010, Pages 361~373
Analysis has been made on the tide/storm surges characteristics near the Korean marginal seas in the 2008 and 2009 years using operational ocean prediction model of the Korea Meteorological Administration(KMA). In order to evaluate its performance, its results were compared with the observed data by tidal stations around Korean Peninsula. The model used in this study predicts very well the characteristics of tide/storm surges near the Korean Peninsula. Simulated storm surges show the evident effects of Typhoons in summer season. The averaged root mean square error(RMSE) of 48 hr forecasting between the modeled and observed storm surges are 0.272 and 0.420 m in 2008 and 2009, respectively. Due to strong sea winds, the highest storm surges heights was found in summer season of 2008, however, in 2009, the high storm surges heights was also found in other seasons. When Typhoon Kalmaegi(2008) and Morokot(2009) approached to Korean Peninsular, the accuracy of model predictions is almost same as annual mean value but the precision accuracy for Typhoon Morakot is lower than of Typhoon Kalmaegi similar to annual results.
Two and Three Dimensional Analysis about the Reflection Coefficient by the Slit Caisson and Resulting Wave Pressure Acting on the Structure
Lee, Kwang-Ho ; Choi, Hyun-Seok ; Baek, Dong-Jin ; Kim, Do-Sam ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 22, issue 6, 2010, Pages 374~386
Recently, the theoretical and experimental research is being made actively in control character of waves of perforated-wall caisson breakwater like the slit caisson. This study showed that the character of reflection coefficient and the wave pressure acting on the front and inner of slit caisson were estimated in two and three dimensional numerical wave flume and compared each other. The numerical experiment was set and conducted by various cases as to a variety of wave steepness under 7 sec, 9 sec, 11sec and 13 sec period condition. In this study using a 2 and 3 dimensional numerical wave flume, it applied the Model for the immiscible two-phase flow based on the Naveir-Stokes Equations. This technique can easily reproduce a complicated physical phenomenon more than others and organize the program simply. According to the results of the experiment, the reflection coefficient was estimated high in short-period waves. However, 2-dimensional numerical experiment and 3-dimensional numerical experiment were the same in case of the long-period waves and high wave steepness. And to conclude in case of short-period waves the pressures were a relatively small difference between the two, but there was a big gap in longperiod waves and high wave steepness.
A Development of 3-D Numeric Model for the Confined Flow and Discharge under Sea Ground
Kim, Sang-Jun ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 22, issue 6, 2010, Pages 387~396
A 3-D numeric model for the confined transient flow under sea ground have been developed. This is FDM model using Gauss-Seidel SOR (successive over-relaxation). This model shows the similar head distribution pattern to Theis analytic solution and MODFLOW simulation. The input flowrate to the aquifer and discharge of well have been compared. And it have been found that mass balance is influenced by the weight factor
, i.e. fullyimplicit method (
=1) shows 5% error, but when
becomes to 0.5(Crank and Nicolson method) the mass balance becomes worse and the model result diverges. And the convergency of the model is not much different when
(over-relaxation factor)=0.8~1.5, but when
>1.5, the model result diverges. The test-run shows that the well discharge becomes smaller when another well is near. This model can cover the isotropy
and inhomogeneity, and can be used for the selection of well site, discharge calculation, and head prediction in case of the artificial recharge etc.
Comparision of Overtopping Performance and Prediction Models for Rubble Mound Breakwaters Armoured Tetrapod
Kim, In-Chul ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 22, issue 6, 2010, Pages 397~404
Laboratory tests of wave overtopping rates for a rubble mound breakwaters armoured Tetrapod were carried out, with varying design waves, crest berm widths and crest freeboards. The objective of this study is to investigate overtopping performance and to examine the characteristics of the widely used overtopping prediction models through the results of laboratory tests. Laboratory tests show that structure slope and wave periods have a considerable influence on overtopping rates, but the difference of overtopping rates related to crest berm widths is slight. Owen(1980)'s prediction considerably overestimates compared to the measured valued. Prediction of Van der Meer et al.(1998) underestimates only for steep slope(
=1.5). Besley(1999)'s and Pedersen(1996)'s predictions have a relatively good agreement with the measured results for slopes with a broader crest berm width. In general, best agreement between measured and predicted overtopping rates is observed using modified Pedersen(1996)'s formula for all test conditions.
The Local Scour around a Slender Pile in Combined Waves and Current
Park, Jong-Hwan ; Kim, Kyoung-Ho ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 22, issue 6, 2010, Pages 405~414
In the study, experiments are performed in the mixing region combined wave and current to investigate the characteristics of local scour around a slender pile. Wave generator and current generator are used for the experiments and currents are co-directions with the waves. The local scour depths around the pipeline are obtained according to the various pipe diameters, wave periods, wave heights, and current velocities. The experiments show that the maximum equilibrium local scour depth increases with pipe diameter, wave period, wave height, and current velocity. Using the experimental results, the correlations of scour depth and parameters such as Shields parameter (
), Froude number (Fr), Keulegan-Carpenter number (KC), Ursell number (
), modified Ursell number (
) and ratio of velocities (
) are analyzed. In the mixing region combined with waves and currents, The Froude number of single parameters is the main parameter to cause the local scour around a slender pile due to waves and current and this means that current governs the scour within any limits of the currents.
Development of Reliability-Based Design Program based on the MATLAB GUI Environment
Jeong, Shin-Taek ; Ko, Dong-Hui ; Park, Tae-Hun ; Kim, Jeong-Dae ; Cho, Hong-Yeon ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 22, issue 6, 2010, Pages 415~422
Development of the reliability-based design program in the GUI environment is inadequate for engineers familiar with the deterministic design to deal with the international design criterion based on the probabilistic design. In this study, the design program based on the GUI environment is developed in order to more efficiently input the design factor and more easily carry out the design works. The GUI environment is the GUIDE (Graphic User Interface Development Environment) tool supported by the latest MATALB version 7.1. In order to test the model reliability, the probabilities of failure (POF) on the breakwater armor block (AB) and gravity quay-wall (QW) in the sliding mode are computed using the model in the Level II and Level III. The POF are 55.4~55.7% for breakwater AB and 0.0006~0.0007% for gravity QW. A non-GUI environment program results of the POF are 55.6% for breakwater AB and 0.0018% for gravity QW. In comparison, the POF difference is negligible for breakwater AB because the exact input design parameters are available, whereas the large POF difference, but within the same order, for gravity QW can be explained by the difference of the input design factors because of the poor input data information.
Dynamic Analysis for the Mooring Safety at KwangYang Port
Kim, Young-Bok ; Jeong, Tae-Gweon ; Kim, Se-Won ; Kim, Jung-Yeop ; Kim, Young-Hun ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 22, issue 6, 2010, Pages 423~428
This study is aiming to find one of reasonable guidelines to select a proper berthing ship at Kwang Yang harbors for loading/unloading for the POSCO(Pohang Steel Co. Ltd.). For dynamic analysis for the moored ships, the selection of subjected vessels has to be given the priority, so that the motion characteristics are figured out. The calculation of the dynamic fluid forces and wave, wind and current forces in time domain are followed. Then, the dynamic mooring analyses are performed. This study might contribute to make a new guideline by which the proper sized and loaded ships could be moored safety at the berths of Kwang Yang Harbor.
Hydraulic Experiments of Stem Waves due to Multi-Directional Random Waves along a Vertical Caisson
Yoo, Hyung-Seok ; Kim, Kyu-Han ; Jung, Eui-Jin ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 22, issue 6, 2010, Pages 429~436
Hydraulic experiments were conducted to analyze the characteristics of stem waves due to multidirectional random wave incidence with the different incident angles of main wave direction. Both multi-directional and uni-directional random waves were used to generate the stem waves and their results were compared with each other. The experiment shows multi-directional random waves developed along the vertical wall tend to increase as the incident angle increases similar to the uni-directional waves. Moreover, the stem wave widths were almost same as those in uni-directional random wave cases. However, the experiment demonstrate the stem wave heights were significantly smaller in multi-directional random wave cases than in uni-directional random wave cases.
Report on the Present Condition and Operating of High Frequency Ocean Surface Radars in Korea
Song, Kyu-Min ; Cho, Chol-Ho ; Jung, Kyung-Tae ; Lie, Heung-Jae ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 22, issue 6, 2010, Pages 437~445
There is increasing interest, on the global basis, in the operation of ocean surface radars for measurement of coastal sea surface conditions to support environmental, oceanographic, meteorological, climatological, maritime and disaster mitigation operations. In south Korea, ocean surface radars are operating to monitoring oil spill, outflow from dike or preventing from safety-accidents in the 6 regions (16 radial sites) by main frequency about 13, 25 and 42 MHz until the present. However, that ocean surface radars have been operated on an experimental spectrum basis. In the results of 3~50 MHz band domestic analysis to improve the regulatory status of the spectrum used by oceanographic radars, it was demonstrated that sufficient frequency bands are available for oceanographic radars on the frequency band above 20 MHz. It is difficult to deploy and operate oceanographic radars in the sub-bands below 20 MHz except for 13 MHz band. For using HF ocean surface radars one should understand the spectrum environment in Korea and should prepare a suitable operating system and data processing techniques.