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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 24, Issue 6 - Dec 2012
Volume 24, Issue 5 - Oct 2012
Volume 24, Issue 4 - Aug 2012
Volume 24, Issue 3 - Jun 2012
Volume 24, Issue 2 - Apr 2012
Volume 24, Issue 1 - Feb 2012
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Probability Density Function of the Tidal Residuals in the Korean Coast
Cho, Hong-Yeon ; Kang, Ju-Whan ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 24, issue 1, 2012, Pages 1~9
DOI : 10.9765/KSCOE.2012.24.1.001
Tidal residual is being an important factor by the influence of the climate change in terms of the coastal safety and defense. It is one of the most important factor for the determination of the reference sea level in order to check the safety and performance of the coastal structures in company with the typhoon intensity variation. The probability density function (pdf) of tidal residuals in the Korean coasts have a non-ignorable skewness and high kurtosis. It is highly restricted to the application of the normal pdf assumption as an approximated pdf of tidal residuals. In this study, the pdf of tidal residuals estimated using the Kernel function is suggested as a more reliable and accurate pdf of tidal residuals than the normal function. This suggested pdf shows a good agreement with the empirical cumulative distribution function and histogram. It also gives the more accurate estimation result on the extreme values in comparison with the results based on the normal pdf assumption.
Linear Shallow Water Equations for Waves with Damping
Jung, Tae-Hwa ; Lee, Chang-Hoon ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 24, issue 1, 2012, Pages 10~15
DOI : 10.9765/KSCOE.2012.24.1.010
Wave characteristics in the presence of energy damping are investigated using the linear shallow water equations. To get the phase and energy velocities, geometric optics approach is used and then these values are validated through numerical experiments. Energy damping affects wave height, phase and energy velocities which result in wave transformation. When the complex wavenumber is used by the Eulerian approach, it is found that the phase velocity decreases as the damping increases while the energy velocity increases showing higher values than the phase velocity. When the complex angular frequency is used by the Lagrangian approach, the energy-damping wave group is found to propagate in the energy velocity. The energy velocity is found to affect shoaling and refraction coefficient which is verified through numerical experiments for waves on a plane slope.
The Cross-sectional Mass Flux Observation at Yeomha Channel, Gyeonggi Bay at Spring Tide During Dry and Flood Season
Lee, Dong-Hwan ; Yoon, Byung-Il ; Kim, Jong-Wook ; Gu, Bon-Ho ; Woo, Seung-Buhm ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 24, issue 1, 2012, Pages 16~25
DOI : 10.9765/KSCOE.2012.24.1.016
To calculate the total mass flux that change in dry and flood season in the Yeomha Channel of Gyeonggi Bay, the 13 hour bottom tracking observation was performed from the southern extremity. The value of the total mass flux(Lagrange flux) was calculated as the sum of the Eulerian flux value and stroke drift value and the tidal residual flow was harmonically analyzed through the least-squares method. Moreover, the average during the tidal cycle is essential to calculate the mass flux and the tidal residual flow and there is the need to equate the grid of repeatedly observed data. Nevertheless, due to the great differences in the studied region, the number of vertical grid tends to change according to time and since the horizontal grid differs according to the transport speed of the ship as a characteristic of the bottom tracking observation, differences occur in the horizontal and vertical grid for each hour. Hence, the present study has vertically and horizontally normalized(sigma coordinate) to equate the grid per each hour. When compared to the z-level coordinate system, the Sigma coordinate system was evaluated to have no irrationalities in data analysis with 5% of error. As a result of the analysis, the tidal residual flow displayed the flow pattern of sagging in the both ends in the main waterway direction of dry season. During flood season, it was confirmed that the tidal residual flow was vertical 2-layer flow. As a result of the total mass flux, the ebb properties of 359 cm/s and 261 cm/s were observed during dry and flood season, respectively. The total mass flux was moving the intertidal region between Youngjong-do and Ganghwa-do.
Effect of Incidence Angle of Current on the Hydraulic Resistance Capacity of Clayey Soil
Kim, Young-Sang ; Han, Byung-Duck ; Kang, Gyeong-O ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 24, issue 1, 2012, Pages 26~35
DOI : 10.9765/KSCOE.2012.24.1.026
Until now, study on the hydraulic resistance characteristics of the ground at the river and the ocean current has been focused on the behavior under uni-directional flow without the direction change of flow. However, recent research result shows that scour rate which were measured under the bi-directional flow was much higher than those measured under uni-directional flow for both fine grained and coarse soil. Since the direction of inflow and return flow at the shore, where the structure will be constructed, is not always
, effect of the incidence angle on the hydraulic resistance capacity of the ground should be examined. Using the improved EFA which can consider the direction change of flow, hydraulic resistance capacities of the artificially composed clayey fine grained soil and clayey sandy soil under
flow angle of incidence were assessed. Test result shows that hydraulic resistance capacity decreases and scour rate increase with the increase of the incidence angle between inflow and return flow. For the low consolidation pressure condition, hydraulic resistance capacity of the fine grained soil decreases rapidly. While the hydraulic resistance capacity of the coarse grained soil decreases more rapidly than fine grained soil under high consolidation pressure. Eventually since the larger the incidence angle between inflow and return flow, the larger the scour rate. Hydraulic resistance capacity under bi-directional flow(
) should be examined for the design purpose.
A Study on the Control of Short-period Waves by Resonator
Lee, Kwang-Ho ; Beom, Seong-Sim ; Kim, Do-Sam ; Park, Jong-Bae ; An, Seong-Wook ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 24, issue 1, 2012, Pages 36~47
DOI : 10.9765/KSCOE.2012.24.1.036
In this study, the control performance of resonator was reviewed through numerical analysis and 3-dimensional hydraulic model experiments by attaching the resonator suggested in the existing studies to the openings of rectangular harbor and breakwater placed in a straight line to reduce short-period waves. In the numerical analysis, linear analysis method of singularity distribution method based on vertical-line Green function and full non-linear analysis method by 3D-NIT model were applied, and the validity of the numerical analysis methods was verified through comparative analysis between results of hydraulic experiments and numerical analysis results. In addition, effectiveness of the resonator was confirmed by reviewing its control performance on the short-period waves through review on the comparison with the case in which the resonator is not attached.
A Study on the Control of Solitary Waves by Resonator
Lee, Kwang-Ho ; Beom, Seong-Sim ; Kim, Do-Sam ; Park, Jong-Bae ; An, Seong-Wook ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 24, issue 1, 2012, Pages 48~57
DOI : 10.9765/KSCOE.2012.24.1.048
In this study, 3-dimensional hydraulic model experiment and 3-dimensional numerical analysis were carried out to review the control performance on the solitary waves by attaching the resonator suggested in this study to the openings of the existing rectangular harbors and breakwaters placed in a straight line. In the numerical analysis, TWOPM-3D of 3-D one-field Model for immiscible TWO-Phase flows method using 3-dimensional numerical wave tank was applied, and the validity of the numerical analysis method was verified through comparative analysis between hydraulic experimental results and numerical analysis results. In addition, the effectiveness of the resonator was identified as a result of review on the control performance to control solitary waves of the resonance devices through comparison with cases where the resonators are attached or not.
Application of Wave Resonator to the Field for Controlling Secondary Undulation
Lee, Kwang-Ho ; Beom, Seong-Sim ; Kim, Do-Sam ; Choi, Nack-Hoon ; Park, Jong-Bae ; An, Seong-Wook ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 24, issue 1, 2012, Pages 58~65
DOI : 10.9765/KSCOE.2012.24.1.058
In this study, to reduce the motion of the vessels resulting from resonance and secondary undulation by long-period waves, numerical review on the control performance of resonator was carried out by attaching the resonator to the established harbor of real waters. In the numerical analysis, CGWAVE MODULE of commercial software SMS(Surface water Modeling System), a finite element model based on 2-dimensional elliptical mild slope equation was applied, and through comparative analysis of the existing experiments and analysis results on the rectangular model ports, the validity of the friction coefficients in which validity and effectiveness of SMS on the secondary undulation analysis is applied was verified. Based on this, the control performance of resonator was confirmed through comparative review of the secondary undulation according to whether or not to attach the resonator to rectangular harbor. In addition, to reduce long-period motion of the moored vessels and the secondary undulation which may occur in Pohang new port, the method to move the resonant period which causes abnormal motion of the vessels to long-term one was discussed through application of the resonators with various sizes, thereby identifying the availability.
Numerical Analyses of 2011 East Japan Tsunami Propagation towards Korean Peninsula
Bae, Jae-Seok ; Cho, Young-Joon ; Kwon, Seok-Jae ; Yoon, Sung-Bum ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 24, issue 1, 2012, Pages 66~76
DOI : 10.9765/KSCOE.2012.24.1.066
The effect of bathymetry near the south sea area of Korea on the propagation of 2011 East Japan Tsunami is analyzed based on the numerical simulation using the finite difference dispersion-correction model. It is found that the bathymetry from the source to Korean Peninsula, such as Nankai Trough, Ryukyu Islands and the topographical lens in the East China Sea, plays an important role to reduce the tsunami height along the south coast of Korea. The mechanism involved in the transformation of tsunamis over those topographies is discussed.