• Journal of Navigation and Port Research
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• v.29 no.3 s.99
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• pp.257-262
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• 2005

Environmental problems and safety problems in coastal area is one of the most important factors for designing coastal structures and maintaining facilities in coastal zone. And thus study on Wave transformation around coastal area is very important to develope a new port or on industrial area. Delft 3D-WAVE is applied to Ulsan new port area and the culculated results are analysed and compared with measured data Delft 3D-wave module is based on SWAN model which considers wave shoaling and refraction for irregular wave. This module also covers wind effect, bottom friction. white-capping and wave breaking effect. The results of this study show a good agreement with measured data and thus Delft 3D-WAVE module can be applied to simulate irregular wave transformation in coastal area.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.298-302
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• 2004

본 연구에서는 낙동강 하구역 해역에서의 폭풍 해일의 특성 및 이를 고려한 외해 압사파랑특성을 고찰하고 연안사주 전면의 입사파랑과 퇴적 특성과의 상호 관계를 고찰하였으며 천해역의 파랑변형을 예측할 수 있는 다방향 불규칙파 묘형을 구성하고 폭풍 해일고를 수심조건에 고려함으로써 하구역 해역에서의 파랑 변형계산을 2차원 평면수치모의실험을 수행하였다. 낙동강 하구역에서 서측에 위치하는 진우도 전면해역이 무명도 전면해역보다 약 1.0배에서 2.0배 크게 파고분포를 나타내었다. 이는 입사하는 파랑의 공간 분포가 사주전면에서 공간적으로 차이가 남을 나타내는 것으로 사주의 퇴적작용에 영향을 줄 것이라고 판단된다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.17 no.3
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• pp.202-212
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• 2005

In the design of an of offshore structure located near an underwater shoal, the same amount of attention given to the wave height may have to be put to the wave induced current as well since some of the wave energy translates to the current. In the present study, two numerical models each based on the nonlinear Boussinesq equation and the linear mild slope equation are applied to calculate the wave deformation and secondly induced current around a shoal. The underwater shoal in Vincent and briggs' experiment (1989) is used here, and all non-breaking wave conditions of the experiment with various monochromatic and unidirectional or multidirectional spectral wave incidences are concerned. Both numerical models clearly showed wave induced currents symmetrically farmed along the centerline over the shoal. The calculated wave heights along a preset line also generally showed very nice agreements with the experimental values.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.439-442
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• 2008

Diffraction of multi-directional random waves passing semi-infinite breakwater is investigated by using analytic solution derived by Penny and Prices(1952). An irregylarity of period and incident angle of waves and regular periods for regular waves are considered in addition by expanding from the past study which used only monochromatic wave in general. The Bretschneider-Mitsuyasu frequency spectrum and Mitsuyasu directional spectrum are used for incident waves. And diffraction of multi-directional random waves is reappeared by decomposing numerical results of several monochromatic waves which have variable period and incident angle. Analytic solution on the diffraction of regular waves and multi-directional random waves calculated in this study.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.2 no.2
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• pp.75-82
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• 1990

A Wave transformation including wave breaking in shallow water region is a non-linear and discontinuous Phenomenon. Therefore, a so-called individual wave analysis (or a wave by wave analysis) rather than spectral approach seems to be adequate to investigate the wave transformation in such regions. In this study, a theoretical joint distribution of wave height, period and wave direction of zero-down crossing waves, which is required in the individual wave analysis in the shallow water region, is derived based on the hypothesis that sea surface is a Gaussian stochastic process and that a band-width of energy spectra is sufficiently narrow. The derived i oint distribution is found to be an effective measure to investigate characteristics of three-dimensional random wave field in shallow water through field measurements.

• Journal of Ocean Engineering and Technology
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• v.20 no.4 s.71
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• pp.83-90
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• 2006

Recently, as the technology of utilization for the ocean space is being advanced, floating structures are asked for being mare and mare huge-scale. A very large floating structure(VLFS) is considered as a flexible structure, because of a quite large length-to-breadth ratio and its geometrical flexibility. The main object of this study is to develop an accurate and convenient method on the hydroelastic response analysis of very large offshore structures on the real sea states. The numerical approach for the hydorelastic responses is based on the combination of the three dimensional source distribution methods, the dynamic response analysis method and the spectral analysis method. A model is considered as many rigid bodies connected elastic beam elements. The calculated results shaw good agreement with the experimental and calculated ones by Ohta.

• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.111-119
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• 2003

In order to improve navigational safety of ships, an ocean wave prediction model of high precision within a short time, dealing with multi-directional random waves from the information of the sea surface winds encountered at the planned ship's course, was introduced for construction of ocean wave forecasting system on the ship. In this paper, we investigated a sea disaster occurred by a stormy weather in the past. We analyzed the sea surface wind first and then carried out ocean wave hindercasting simulations according to the routes the sunken vessel. From the result of this study, we concluded that the sea disaster was caused by rapidly developed iou pressure system Okhotsk Sea and the predicted values by the third generation wave prediction model(WAM) was agreed well with the observed significant wave height, wave period, and directional wave spectrum. It gives a good applicability for construction of a practical on-board calculation system.