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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 25, Issue 6 - Dec 2013
Volume 25, Issue 5 - Oct 2013
Volume 25, Issue 4 - Aug 2013
Volume 25, Issue 3 - Jun 2013
Volume 25, Issue 2 - Apr 2013
Volume 25, Issue 1 - Feb 2013
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Stability Formula for Rakuna-IV Armoring Rubble-Mound Breakwater
Suh, Kyung-Duck ; Lee, Tae Hoon ; Matsushita, Hiroshi ; Nam, Hong Ki ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 25, issue 4, 2013, Pages 181~190
DOI : 10.9765/KSCOE.2013.25.4.181
In this study, a total of 51 cases of hydraulic model tests has been conducted for various wave conditions and slope angles of breakwater to develop a stability formula for Rakuna-IV armoring a rubble-mound breakwater. The stability number of the formula is expressed as a function of relative damage, number of waves, structural slope, and surf similarity parameter. The stability formula is derived separately for plunging and surging waves, the greater of which is used. The transitional surf similarity parameter from plunging waves to surging waves is also presented. Lastly, to explain the stability of Rakuna-IV to the engineers who are familiar with the stability coefficient in the Hudson formula, the required weight of Rakuna-IV is calculated for varying significant wave height for typical plunging and surging wave conditions, which is then compared with those of the Hudson formula using several different stability coefficients.
Analysis of Confidence Interval of Design Wave Height Estimated Using a Finite Number of Data
Jeong, Weon-Mu ; Cho, Hong-Yeon ; Kim, Gunwoo ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 25, issue 4, 2013, Pages 191~199
DOI : 10.9765/KSCOE.2013.25.4.191
It is estimated and analyzed that the design wave height and the confidence interval (hereafter CI) according to the return period using the fourteen-year wave data obtained at Pusan New Port. The functions used in the extreme value analysis are the Gumbel function, the Weibull function, and the Kernel function. The CI of the estimated wave heights was predicted using one of the Monte-Carlo simulation methods, the Bootstrap method. The analysis results of the estimated CI of the design wave height indicate that over 150 years of data is necessary in order to satisfy an approximately
10% CI. Also, estimating the number of practically possible data to be around 25~50, the allowable error was found to be approximately
16~22% for Type I PDF and
18~24% for Type III PDF. Whereas, the Kernel distribution method, a typical non-parametric method, shows that the CI of the method is below 40% in comparison with the CI of the other methods and the estimated design wave height is 1.2~1.6 m lower than that of the other methods.
Characteristic Analysis of the Tidal Residuals' Mid/Long-period Components Using a Wavelet Method
Kang, Ju Whan ; Kim, Yang-Seon ; Shim, Jae-Seol ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 25, issue 4, 2013, Pages 200~206
DOI : 10.9765/KSCOE.2013.25.4.200
Fourier analysis and a wavelet method were carried out to elucidate the characteristics of tidal residual components in coastal waters. The result of Fourier analysis shows tide-induced and monsoon-induced residuals are conspicuous at the short period and mid period, respectively. The tidal residuals were decomposed by period from 3 hours to 8 months and the characteristics of their components were shown by reconstituting them with short periods less than 24 hours, mid-periods between 1 day and 16 days and long periods longer than 1 month. The tidal residuals in the short period, i.e., tide-induced components, being based on the tidal elevation prediction errors, appear in the West Sea with high tidal ranges and do not have much seasonal fluctuation. Additionally, the period of typhoon induced surge ranges more or less than 12 hours. The mid-period components were clearly generated mainly in the West Sea during the winter and largely affected by monsoon. Accordingly, the pure surge height components were concentrated on the mid-period and had clear features for each coastal waters. The long period components show similar characteristics at all stations and are considered to stem from variations of mean sea levels.
Characteristics of Tidal Current and Tidal Residual Current in the Chunsu Bay, Yellow Sea, Korea based on Numerical Modeling Experiments
Jung, Kwang Young ; Ro, Young Jae ; Kim, Baek Jin ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 25, issue 4, 2013, Pages 207~218
DOI : 10.9765/KSCOE.2013.25.4.207
This study is based on a series of numerical modeling experiments to understand the circulation and its change in the Chunsu Bay (CSB), Yellow Sea of Korea. A skill analysis was performed for the tidal height and tidal current of the observation data using the amplitude and phase of the 4 major tidal constituents respectively for verification of modeling experimental results. As a result, most of the skill score was seen to be over 90%, so numerical model experiment results can be said to be in good agreement with the observed tidal height and tidal current. Tidal wave proceeded from the entrance of the CSB towards inside, and the tidal range gradually increased to the north. It took about 10 to 30 minutes for the tidal wave to reach to northern end. The tidal wave showed a characteristic to rotate counter-clockwise in the southern part. The tidal current flowed to the north-south direction along the bottom topography; the angle of the major axis appeared alongside the isobath. It showed the characteristics of reversing tidal current with the minor axis less than 10% of the major axis. The strength of the tidal residual current that is influenced by geographical factors including bathymetry and coastline showed the range of 1~30 cm/sec, greater in the south channel and smaller in northern Bay. Two pairs of cyclonic/anti-cyclonic eddies around Jukdo and 3~4 pairs of strong eddies at the southern part of CSB in hundreds of m to a few km size by relative vorticity derived from the tidal residual current.
Changes in Sea Water Characteristics Due to Operation of Shihwa Tidal Power Plant
Kang, Young Seung ; Chae, Yeongki ; Lee, Hyung Rae ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 25, issue 4, 2013, Pages 219~235
DOI : 10.9765/KSCOE.2013.25.4.219
In order to investigate the changes in sea water characteristics and stratification due to operation of Shihwa tidal power plant, three dimensional numerical model is used. In summer, the density of inner part of Shihwa Lake is more affected by salinity than water temperature due to fresh water discharge. Before tidal power plant operation, the sea water characteristics in Shihwa Lake shows relatively high temperature and low salinity. After tidal power plant operation, water temperature decreases slightly and salinity tends to increase in Shihwa Lake. Also, density increases and stratification tends to weaken by mixing with sea water.
Fragility Assessment of Offshore Wind Turbine by Ship Collision
Cho, Byung Il ; Kim, Dong Hyawn ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 25, issue 4, 2013, Pages 236~243
DOI : 10.9765/KSCOE.2013.25.4.236
Offshore wind turbines has to be proved against accidental events such as ship collision. In this study, ship collision fragility analysis of offshore wind turbine is done. Dynamic collision analysis is accomplished by considering soil foundation interaction and fluid structure interaction. Uncertainties due to ship weight and speed, angle are also considered. By analyzing dynamic response of offshore wind turbine, fragility curves are obtained for different damage levels. They can be used for restricting boat speed around the wind turbine and allowable size of the boat for inspection and for other purposes. Results of the fragility, it was confirmed fragility of collision speed of bulk ship of 30,000DWT and 850ton barge ship.
Change of Nearshore Random Waves in Response to Sea-level Rise
Cheon, Se-Hyeon ; Suh, Kyung-Duck ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 25, issue 4, 2013, Pages 244~254
DOI : 10.9765/KSCOE.2013.25.4.244
In this study, a method has been developed for estimating the change of nearshore random waves in response to sea-level rise, by extending the method proposed for regular waves by Townend in 1994. The relative changes in wavelength, refraction coefficient, shoaling coefficient, and wave height for random waves are presented as functions of relative change in water depth. The changes in wavelength and refraction coefficient are calculated by using the significant wave period and principal wave direction in the regular-wave formulas. On the other hand, the changes in shoaling coefficient and wave height are calculated by using the formulas proposed for shoaling and transformation of random waves in the nearshore area including surf zone. The results are proposed in the form of both formulas and graphs. In particular, the relative change in wave height is compared with the result for regular waves.
Spatial Distribution and Time Variation of M
Tide and M
Tide in the Western Coast of Korea
Jung, Tae Sung ; Jeong, Jin Kwang ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 25, issue 4, 2013, Pages 255~265
DOI : 10.9765/KSCOE.2013.25.4.255
In the coastal region of Korea, historical tide harmonic constants were collected. Long-term tides and short-term tides observed by the KHOA were analyzed by a tide harmonic analysis method. Based on the harmonic constants, tidal characteristics such as tide asymmetry in Korean coastal waters were investigated. The harmonic constants obtained from the long-term tide data in the western coast have been used to show the relation between tide variation and reclamation project.
amplitudes in the western coast have been decreased and
phases were faster.
amplitudes also were reduced and
phases were faster in overall. In Mokpo and Kunsan tidal nonlinearity is relatively conspicuous. Overall, non-linearity of tidal currents is higher in the tidal channels flowing fast. The tidal non-linearity has increased by the development projects including large reclamation. The flood dominant characteristic in the northern and central part of Korean western coastal waters and the ebb dominant characteristic in the southern part have been intensified. The construction of Saemangeum sea dike has significantly changed the tidal characteristic in Korean western coastal waters.