• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.3
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• pp.383-388
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• 2014

This paper describes a wave modeling method using low-cost sensors. Wave modeling is applied to the wave monitoring system for accurate measurement of ocean wave parameters. The observation of ocean wave parameters is necessary to improve the accuracy of forecast of ocean wave condition. However, the ocean wave parameters measured by a low-cost wave monitoring system suffer from several errors. Therefore we introduce a wave modeling method to compensate the ocean wave parameters corrupted by errors. The proposed method is analyzed using experiments within controlled environment. It is verified that the accuracy of low-cost wave monitoring system can be increased by the proposed method.

• Journal of Ocean Engineering and Technology
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• v.37 no.2
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• pp.68-79
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• 2023

Even though submerged breakwater reduces incident wave energy, it redistributes the coastal area's wave-induced current, sediment transport, and morphological change. This study examines the coastal hydrodynamics and the morphological response of a wave-dominated beach with submerged breakwaters installed through field observation and quasi-3D numerical modeling. The pre-and post-storm bathymetry, water level, and offshore wave under storm forcing were collected in Bongpo Beach on the East coast of Korea and used to analyze the coastal hydrodynamic response. Four vertically equidistant layers were used in the numerical simulation, and the wave-induced current was examined using quasi-3D numerical modeling. The shore normal incident wave (east-northeast) generated strong cross-shore and longshore currents toward the hinterland of the submerged breakwater. However, the oblique incident wave (east-southeast) induced the southeastward longshore current and the sedimentation in the northeast area of the beach. The results suggested that the incident wave direction is a significant factor in determining the current and sediment transport patterns in the presence of the submerged breakwaters. Moreover, the quasi-3D numerical modeling is more appropriate for estimating the wave transformation, current, and sediment transport pattern in the coastal area with the submerged breakwater.

• Journal of the korean society of oceanography
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• v.39 no.1
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• pp.35-45
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• 2004

Based on the MASNUM wave-current coupled model, the temperature and salinity structures along $36^{\circ}N$ in the Yellow Sea are simulated and compared with observations. Both the position and strength of the simulated thermocline are similar to data analysis. The wave-induced mixing is strongest in winter and plays a key role in the formation of the upper mixed layer in spring and summer. Numerical experiments suggest that in the coastal area, wave-induced mixing and tidal mixing control the vertical structure of temperature and salinity.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.1
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• pp.1-11
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• 2013

The aim of this study was estimated the characteristics of the wave propagation by the water level conditions using a numerical modeling method at the Wando sea area. For three cases numerical simulation on the condition of incident and incoming of the deepwater design wave and the season normal wave, the spatial distribution of the incident wave at study area were investigated. And the calculated numerical modeling results were compared with measured field wave data. According to on-site wave data measured for 18 days, the range of the significant wave height and period were 0.10~1.14 m, 4.35~8.74 sec, respectively, and the maximum wave height were 0.15~1.66 m. From the results of numerical model for offshore design wave incident, the wave height attacked from Southern-East direction at this study area were over maximum 10.5 m because of rapidly change of water depth. Numerical modeling by three water level conditions of Approxmate Lowest Low Water Level(Approx. L.L.W), Mean Sea Level(M.S.L) and Approximate Highest High Water Level(Approx. H.H.W) were practiced. From the results for the case of Approx. H.W.L, variations of wave height at the back area of islands were about 1.6 m at maximum value for the case of deepwater design wave incoming. The significant wave heights of winter season were bigger than summer under normal wave condition, the incident wave height over 5.5 m decreased by shielding effect of islands. The change of maximum wave height at summer season were distinct than winter and was about 1.2 m and 0.8 m, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.12 no.3
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• pp.285-291
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• 1987

Seismic waves are attenuated by losses of energy as they propagate through the earth. One way to model this numerically is to make the velocity a complex number, the real part giving the phase velocity and the imaginary part the attenuation. This models wave propagation in a medium for which the logarithmic decrement is independent of frequency(attenuation coefficient is proportional to frequncy). The aim is to modify forward and inverse numerical modeling so that attenuation can be specified as a function of position.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.438-440
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• 2003

This study is introducing a new approach of ATInSAR hologram for modeling wave refraction spectra pattern. TOPSAR data with L$_{-HH}$ and C-vv bands utilized spatial variation of wave refraction. Based on the phase information in along track interferometry, and ATInSAR hologram the quantitative information such swell wave height and spectra energy have been modeled. The phase information in ATInSAR hologram images can be transferred to wave refraction The ATInSAR hologram can be used to investigate the wave refraction pattern along the coastal waters. The fringe information pattern was shown to be useful in modeling wave refaction spectra varaition. The hologram interferometry wave refraction model consists of two sub-models. The purpose of first sub-model is to determine the swell wave height by using ATInSAR. Second sub-model aims to generate the holographic interferometry from the information of two wave spectra which detected by ATInSAR technique. The azimuth cut-off variations along the fringe patterns will be estimated. As azimuth cut-off contains the wave height information which could be used the significant wave height variation in convergence and divergence zone.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.167.2-167.2
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• 2011

Motions in nature, for example ocean wave, has been playing a significant role for generating electricity production in our modern life. This paper presents an innovative approach for electric power conversion of the vast ocean wave energy. Here, a floating-buoy wave energy converter (WEC) using hydrostatic transmission (HST), which is shortened as HSTWEC, is proposed and designed to enhance the wave energy harvesting task during all wave fluctuations. In this HSTWEC structure, the power take-off system (PTO) is a combination of the designed HST circuit and an electric generator to convert mechanical energy generated by ocean wave into electrical energy. Several design concepts of the HSTWEC have been considered in this study for an adequate investigation. Modeling and simulations using MATLAB/Simulink and AMESim are then carried out to evaluate these design concepts to find out the best solution. In addition, an adaptive controller is designed for improving the HSTWEC performance. The effectiveness of the proposed HSTWEC control system is finally proved by numerical simulations.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.330-332
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• 2005

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.415-429
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• 2002

Various modeling techniques for ultrasonic wave propagation and scattering problems in finite solid media are presented. Elastodynamic boundary value problems in inhomogeneous multi-layered plate-like structures are set up for modal analysis of guided wave propagation and numerically solved to obtain dispersion curves which show propagation characteristics of guided waves. As a powerful modeling tool to overcome such numerical difficulties in wave scattering problems as the geometrical complexity and mode conversion, the Boundary Element Method(BEM) is introduced and is combined with the normal mode expansion technique to develop the hybrid BEM, an efficient technique for modeling multi-mode conversion of guided wave scattering problems.

• Explosives and Blasting
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• v.23 no.3
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• pp.27-42
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• 2005

An explosion modeling technique was developed by using the spherical discrete element code, $PFC^{3D}$, which can be used to model the dynamic stress wave propagation phenomenon. The modeling technique is simply based on an idea that the explosion pressure should be applied to a $PFC^{3D}$ particle assembly not in the form of an external force (body force), but in the form of a contact force (surface force). The stress wave propagation modeling was conducted by simulating the experimental approach based on the Hopkinson's effect combined with the spatting phenomenon that had previously been developed to determine the dynamic tensile strength of Inada granite. As a result, the stress wave velocity obtained by the proposed modeling technique was 4167 m/s, which is merely $3\%$ lower than the actual wave velocity of 4300 m/s for an Inada granite.