• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.6-10
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• 2001

Water waves propagate over irregular bottom bathymetry are transformed by refraction, diffraction, shoaling, reflection etc. Principal factor of wave transform is bottom bathymetry, but in case of current field, current is another important factor which effect wave transformation. The governing equation of this study is develope as wave-current equation type to investigate the effect of wave-current interaction. It starts from Berkhoff's(1972) mild slope equation and is transformed to time-dependent hyperbolic type equation by using variational principal. Finally the governing equation is shown as a parabolic type equation by splitting method. This wave-current model was applied to the kwangan beach which is located at Pusan. The numerical simulation results of this model show the characteristics of wave transformation and flow pattern around the Kwangan beach fairly well.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1447-1454
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• 2013

In this study, we developed the equation of ship wave crests in intermediate as well as deep waters by extending Kelvin's (1887) theory using the recursive relation for the dispersion relation. The present equation can be applied for varying water depth as well as constant water depth. Using FLOW-3D we conducted numerical experiments to verify analytical prediction. The ship wave crest patterns became asymmetric on a plane slope when the ship propagates alongshore direction. That is, in shallower side, wave crests tend to be parallel to the coastline due to refraction and, in deeper side, wave crests tend to be orthogonal due to reverse refraction.

• Water for future
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• v.17 no.2
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• pp.113-124
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• 1984

The equations for the wave orthogonals and wave heights are presented along the depth using time as the independent variable, The effect of wave refracion is included. In this paper, a numerical procedure is described for the calculation and two analytical solutions are presneted in case of straight and parallel bottom contours and horizontal bottom in order to check the computed results. The computer outputs are in the form of automatically plotted wave orthogonals and wave heights along the wave path. In practical calculation of wave heights, Samchuckk Pohang, and Hanlim are selected as plane sloping bottoms.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.5
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• pp.335-342
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• 1991

A real-tme nonlinear parameter tomography is pumping wave method. This tomorgraphy has a merit which requires no 180$^{\circ}$ projection datum, while the ray-bending effect is remrkably remained on the reconstructed image. In this paper we intend to compensate this ray-bending effect using the perturbation method. Impulsive pumping wave makes derived compensative term simple form, nad the compensative image is easily obtained. We perform computer simulation to confirm the improvement of corrected imate.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.19 no.6
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• pp.557-564
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• 2007

The effect of wave and current interactions on regular wave transformation over a submerged elliptic shoal is investigated based on numerical simulations of the Vincent and Briggs experiment [Vincent, C.L., Briggs, M.J., 1989. Refraction-diffraction of irregular waves over a mound. Journal of Waterway, Port, Coastal and Ocean Engineering, 115(2), pp. 269-284]. The numerical simulations are conducted by constituting two numerical model systems: a combination of SWAN(a wave model) plus SHORECIRC(a current model) and a combination of REF/DIF 1(a wave model) plus SHORECIRC. A time dependent phase-resolving wave-current model, FUNWAVE, is also utilized to simulate the experiment. In the simulations, the breaking-induced currents defocus waves behind the shoal and bring on a wave shadow zone that shows relatively low wave height distributions. The computed results of the two model systems agree better with the measurements than the computed results obtained by neglecting wave-current interaction do. However, it is found that the radiation stresses for standing waves are misevaluated in the wave models. In addition, the results of FUNWAVE show very good agreement with the measurements. The agreement indicates that it is necessary to take into account the effect of breaking-induced current on wave refraction when wave-breaking occurs over a submerged shoal.

• Journal of Navigation and Port Research
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• v.28 no.1
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• pp.97-104
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• 2004

Introduction of wave model, take into account the effect of tide, wind and wave induced currents at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster protection problems. As the steady state spectral wave model could simulate depth induced wave shoaling and refraction, current induced refraction effect, steepness induced wave breaking, diffraction, wind wave growth, wave-wave interaction, and wave-current interaction that redistribute energy, this would support and compensate the gap in the real field of design where other wave models could not deal and cause wrong estimation. In this study, for better understanding and analysis of wave transformation process, we applied the spectral wave model to the large coastal waters near Gaduck Island where the Busan new port construction project is going on. We also compared the simulation results with the calculatea from the existing model. From such a trial of this study, we hope that broader and safer use of the spectral model in the area of port design and disaster prevention system come through in near future.

• Geophysics and Geophysical Exploration
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• v.16 no.3
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• pp.109-118
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• 2013

On and near the 23-m high earthen Cheongcheon dam in Boryeong City, Korea, short seismic refraction and surface-wave profiles were conducted using a 5-kg sledgehammer. From vertical and horizontal components of the seismic waves, near-surface P-wave velocities (${\nu}_p$) and S-wave velocities (${\nu}_s$) were derived by inverting first-arrival refraction times and dispersion curves of Rayleigh waves. Average ${\nu}_p$ and ${\nu}_s$ for the Jurassic sedimentary basement were determined to be 1650 and 950 m/s at a depth of 30 m directly beneath the dam and 1650 m/s and 940 m/s at a depth of 10 m at the toe of the dam, respectively. The dynamic Poisson's ratio for these strata were therefore in the range of 0.24 to 0.25, which is consistent with ratios for consolidated sedimentary strata. Near a 45-m borehole 152 m downstream from the dam crest, an SH tomogram indicates a refraction boundary with an average ${\nu}_s$ of 870 m/s at depths of 10 ~ 12 m. At this site, the overburden comprises the upper layer with relatively constant ${\nu}_p$ and ${\nu}_s$ around 500 and 200 m/s, respectively, and the lower layer in which both ${\nu}_p$ and ${\nu}_s$ increase with depth almost linearly. The dynamic Poisson's ratios for the overburden were in the range of 0.30 to 0.43.

• Geophysics and Geophysical Exploration
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• v.20 no.1
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• pp.43-48
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• 2017

The applicability of refraction survey has been tested using a wave glider widely used in long-term ocean observations around the world. To record seismic refractions, a single channel streamer with metal weight and a seismic recording system were mounted on the wave glider. We used GPS precise time synchronization signal and radio frequency (RF) communication to synchronize shot and recorder triggers and to control acquired data quality in real time. When the wave glider is positioned close to the set point, a 2,000 J sparker is exploded along the designed track at 2 second intervals. Through the test survey, we were able to successfully acquire refractions from the subsurface.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1994.07a
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• pp.33-38
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• 1994

• Journal of Ocean Engineering and Technology
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• v.12 no.1
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• pp.120-127
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• 1998

An Elliptic model for calculating the combined refraction/diffraction of monochromatic linear waves is developed, including a term which allows for the dissipation of wave energy. Conjugate gradient method is employed as a solution technique. Wave height variations are calculated for localized circular and rectangular dissipation areas. It is shown that the numerical results agree very well with analytical solution in the case of circular damping region. The localized dissipation area creates a shadow region of low wave energy and the recovery of wave height by diffraction occurs very slowly with distance behind the damping region.