• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.5
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• pp.307-321
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• 2020

The design and the construction are carried out by installation of new caissons on the back or the front of old caissons to increase the stability of old caisson breakwater. In this study, we use the eigenfunction expansion method to analyze the effects of wave structure interaction when new circular caissons are installed on the back or the front of old caissons. The comparison of numerical results between present method and Williams and Li is made, and the wave force and the wave run-up acting on each circular caisson are calculated for various parameters by considering the wave structure interaction.

• New & Renewable Energy
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• v.3 no.3
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• pp.28-35
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• 2007

In this study, the wave power resources at the three locations [Sokcho, Hupo, and Onsan] on the east coast of Korea were estimated by using the field measurement data and were compared with the results of previous researches. It was found that seasonal variation of the wave power is very significant on the east coast of Korean peninsula. The wave power was the smallest in the summer season at all the locations. At Hupo and Onsan, the highest value of the monthly-averaged wave power was observed in September, probably because the pathways of typhoon in September were close to both locations. At the northest location, Sockcho, in contrast, the monthly highest value of the wave power appeared in January, probably owing to the influence of storm waves driven by Donghae twister. The estimated annual average wave power was 4.5 kW/m at Sokcho, which was about two times larger than those at other two locations. It is noteworthy that this result is completely different from past researches based on wave hindcasting data. In addition, the estimates of wave power by the past researches seemed to be smaller than those of the present study, especially at the northern region of the east coast.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.2
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• pp.135-140
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• 1995

The procedure of wave energy dissipation due to breaking has been investigated with trains of the regular wave. To obtain the data for wave breaking and its deformation, experiments have been conducted by utilizing a horizontal step adjoining to a combined slope of 1/20 and 1/10. After breaking the wave height decreases by dissipation but attains a stable value at some distance from the breaking point Experimental results show that the stable wave is considerably affected by the wave period. The study gives the general form of stable wave height A new one-dimensional wave deformation model is proposed. being coupled with an approximated shoaling coefficient before wave breaking and the new energy dissipation term after breaking. It was compared with the experimental data. It predicts well the wave height deformation before and after wave breaking even on the abrupt change of the depth.

• Journal of Navigation and Port Research
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• v.41 no.5
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• pp.329-336
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• 2017

This study suggests a general process of analyzing the mooring and cargo handling limit waves, which is an incident to the new energy port under long wave agitation. To reduce damages of ships and harbor structures due to strong wave responses, it is necessary to predict the change of wave field in the mooring berth to make the proper decision by dock master. The berthing area at a new LNG port in the east coast of Korea in this study is frequently affected by oscillations from waves of 8.5~13s periods in the wintertime. The long period waves give difficulties on port operation by lowering the annual berthing ratio. It needs to find the event waves from the real time offshore wave records, which cause over the mooring limits. For that purpose, the wave records from field measurement and offshore wave buoy were analyzed. From numerical simulation, the response characteristics of long period waves in the berthing area were deduced with or without breakwater expansion plan, analyzing the offshore field wave data collected for two years. Some event wave cases caused over the cargo handling and mooring limits as per the standard Korean port design guideline, and those were used for the decision of port operation by dock master, comparing with the real time offshore wave observations.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.4 no.1
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• pp.22-30
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• 2001

A new concept wave absorber is proposed. It is a net type wave absorber. Its efficiency was reported in another publication. Since it is based on new concept, the traditional wave absorber theory is not applicable. It is modeled by introducing damping terms in linearized free surface boundary conditions in this study. The length and the thickness of the wave absorber are modeled by the length and the coefficient of the damping terms. Series of experiments are carried out to get the data for the coefficients of the damping term. The boundary element method is adopted to solve the system. The predicted wave heights show excellent agreement with those of experiments when the lengths of the incoming waves are within the length of the wave absorber.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.208-213
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• 2002

A new method is presented for the isolation of resonances from scattered waves for elastic wave resonance scattering problems. The resonance scattering function consisting purely of resonance information is defined. Elastic wave resonance scattering from a water-filled cylindrical cavity imbedded in an aluminum matrix is numerically analyzed. The classical resonance scattering theory and the new method compute different magnitudes and phases of the resonances from each partial wave, and therefore. their total resonance spectra are quite different. The exact $\pi$ - radians phase shifts through the resonance and anti-resonance frequencies show that the proposed method properly extracts the vibrational resonance information of the scatterer compared to resonance scattering theory.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1501-1504
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• 2008

By applying sonic wave vibration technology in weight exercise equipment, we introduced an completely new concept of device into the fitness and medical industry creating a new trend. Sonic wave leg press exercise system which got over the limit of technology will be easily accessible not only by professional athletes but also by ordinary users and even minority groups such as disabled, elderly, children.

• Journal of the Korean Society for Railway
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• v.17 no.6
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• pp.397-401
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• 2014

In order to rationally design a new conceptual submerged floating railway, prediction of wave forces applied to the structure is very important. In this paper, equations to calculate such forces based on hydrodynamic theories were proposed and model tests were carried out. Inertia forces and drag forces, calculated using Morison's equation and the linear small amplitude wave theory, were in good agreement with the results from model tests conducted in a wave making tank. Drag forces were negligible compared with inertia forces. Also, wave forces showed linear variation with the changing wave heights. It was revealed that the linear wave theory and Morison's equation can give a simple and useful solution for the prediction of wave forces in the initial design stage of a submerged floating railway.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.3
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• pp.155-164
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• 1987

A new design method of rubble mound structures that includes the considerations of stability and wave control is proposed. Using the method, design of structures that reduce the wave reflection and run-up and increase the rubble stability is assured under the given wave conditions. The new design formula is developed so that the allowable prcentage of damage and the wave grouping effects on rubble stability are also considered in design. For this a new definition of the mean run-sum is made. Finally, the new method is applied for the design of uniform and composite slope rubble mound structures and the significant advantages are found.

• Journal of Ocean Engineering and Technology
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• v.24 no.1
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• pp.39-46
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• 2010

The calmness inside a harbor plays an important role in the appropriate disposition of harbor structures. However, it is not easy to acquire accurate computational results because these are affected by many factors concerned with wave transformation. Recently, numerical model tests, which are quicker and more economical than hydraulic model experiments, were carried out for the purpose of analyzing wave height distributions in harbors. This paper presents a numerical model that is able to calculate wave heights inside a harbor. It is based on a time-dependent mild slope involving wave refraction, diffraction, shoaling effect, and reflection. In particular, arbitrary reflectivity is used at the boundary in order to simulate the real harbor reflection condition. The proposed numerical model is applied to Samcheon new-harbor in order to investigate harbor calmness.