• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.421-421
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• 2017

In order to secure the safety of coastal areas from the continuous storm surge in Korea, it is important to predict the wave movement and properties accurately during the storm event. To improve the accuracy of the storm simulation, and to quantify coastal risks from the storm event, the dependencies between wave height, wave period, and storm duration should be analyzed. In this study, therefore, copulas were used to develop multivariate statistical models of sea storms. A case study of the east coast of Korea was conducted, and the dependencies between wave height, wave period, water level, storm duration and storm interarrival time were investigated using Kendall's tau correlation coefficient. As a result of the study, only wave height, wave period, and storm duration appeared to be correlated.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.1
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• pp.128-136
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• 2008

Recently, the unusual climate change is happening from the global warming in the whole world, the Korean peninsula is also no exception. It is predicted by many researchers that, in the near future, the Super-Typhoon of overwhelming power will occur due to rising temperatures on the sea surface around the Korean peninsula. In this study, numerical simulation has been performed with the Super-Typhoons which combined route of Typhoon Maemi with typhoon conditons of Hurricane Katrina (New Oleans in U.S.A, 2005), Typhoon Durian (philippine, 2006) and Typhoon Vera (Ise Bay in Japan, 1959) at Busan and Gyeongnam coastal area which has been badly damaged due to storm surge every year. From the numerical results, it is revealed that the storm surge heights of the Super-Typhoons are higher than that of Maemi, specially the storm surge height in the case of Katrina is about 4 times larger. So, it can be pointed out that the construction of countermeasures against disasters are very important in order to prepare against an attack of the Super-Typhoons.

• Plant Journal
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• v.15 no.4
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• pp.36-42
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• 2019

In recent, according to the tightening of environment regulation policy, the height of the site of the power plant is increased and the length of the cooling water pipe is increased. This has a serious impact on the stability of the plant. This study analyzes the transient phenomenon using LIQT 7.2, an unsteady state one-dimensional analysis software, to secure the stability of 1,000 MW high-capacity coal-fired power plant cooling water system with high head. To prevent water hammer, The effects on performance characteristics were predicted by individual and combination application. The surge pressure of the cooling water which occurs when the pump was stopped without installing the anti-surge devices was the largest at the pump outlet side. The most effective and simple way to reduce surge pressure in these cooling water systems is to combine a vacuum breaker with a hydraulic non-return valve, which is an essential device for pump protection.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.611-614
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• 2009

Understanding the severity of the typhoon-induced storm-surge helps in planning reaction and in preventing further disaster. Natural disasters due to the storm-surge are predictable from accurate observations and forecasts from numerical simulations. What we can do is to make intelligent effort to minimize the loss due to the disaster to the most extent with the technology of early warning, forecast and prevention activity. In this paper, we propose the design of GIS-based Web Service System to visualize the time-varying storm-surge's height and wind field data effectively with 3 different kinds of resolution for predict and prevent storm-surge disasters. This system is one of the efforts to provide the storm-surge forecast service to general public and share two-way more helpful information to coastal resident through the Internet.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.1
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• pp.1-14
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• 2009

Linear-tracked typhoons were simulated to investigate the effect of parameter sensitivity at Gyeongnam coastal zone. To do this, appropriateness of the linear-tracked MAEMI(0314) was tested and 175 scenarios were simulated on the basis of virtual MAEMI. The results show surge heights are relatively large at Masan and Tongyeong, and it can be attributed to topographical effects. At Masan, 2.5 m-surge height is probable with the same intensity but slightly different track from the real typhoon MAEMI. At the other stations, surge heights induced by real MAEMI are nearly same as the maximum heights of the virtual typhoons, which indicates the real track of the typhoon MAEMI was almost the most severe one. Surge heights caused by the barometric effect are higher than those by the wind effect, and the former effect shows the maximum at the eye of typhoon.

• 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 the Korean GEO-environmental Society
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• v.3 no.2
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• pp.71-79
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• 2002

A numerical simulation has been performed on the generation of the coastal cliff which lies as the distinct boundary between the beach and the hinterland. As a result of storm surge, it is known that the steeper the initial beach slope, the larger the generation of the coastal cliff. The rise of water level added the mean water level accelerates the generation of the coastal cliff. In addition, the longshore distribution of the incident wave height is one factor that bring about the generation of the non-uniform coastal cliff in longshore direction. Therefore this study will be able to use for expecting the formation and erosion of coastal cliff in sand beach.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.1
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• pp.19-26
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• 2000

A numerical model is applied for predicting two-dimensional beach and dune erosion during severe storms. The model uses equation of sediment continuity and dynamic equation, governing the on-offshore sediment transport due to a disequilibrium of wave energy dissipation. And the model also uses sediment transport rate parameter K from dimensional analysis instead of that recommended by Kriebel. During a storm, a beach profile evolves to a form where the depth at the surf zone is related to the distance seaward of the waterline. In general, the erosion in the beach profile is found to be sensitive to equilibrium profile parameter, sediment transport rate parameter, storm surge level and breaking wave height.

• Ocean Systems Engineering
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• v.4 no.4
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• pp.327-342
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• 2014

The tension leg platform (TLP) is one of the compliant structures which are generally used for deep water oil exploration. With respect to the horizontal degrees of freedom, it behaves like a floating structure moored by vertical tethers which are pretension due to the excess buoyancy of the platform, whereas with respect to the vertical degrees of freedom, it is stiff and resembles a fixed structure and is not allowed to float freely. In the current study, a numerical study for square TLP using modified Morison equation was carried out in the time domain with water particle kinematics using Airy's linear wave theory to investigate the effect of changing the tether tension force on the stiffness matrix of TLP's, the dynamic behavior of TLP's; and on the fatigue stresses in the cables. The effect was investigated for different parameters of the hydrodynamic forces such as wave periods, and wave heights. The numerical study takes into consideration the effect of coupling between various degrees of freedom. The stiffness of the TLP was derived from a combination of hydrostatic restoring forces and restoring forces due to cables. Nonlinear equation was solved using Newmark's beta integration method. Only uni-directional waves in the surge direction was considered in the analysis. It was found that for short wave periods (i.e., 10 sec.), the surge response consisted of small amplitude oscillations about a displaced position that is significantly dependent on tether tension force, wave height; whereas for longer wave periods, the surge response showed high amplitude oscillations that is significantly dependent on wave height, and that special attention should be given to tethers fatigue because of their high tensile static and dynamic stress.

• Journal of Fisheries and Marine Sciences Education
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• v.18 no.2
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• pp.137-149
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• 2006

The typhoon, heavy rain, blizzard, storm and heavy snowfall had the main caused of natural disasters occurred in Korea from 1993 to 2002. Among them, typhoon has responsible for biggest disaster, recording about 47.4% of total economic damage. Typhoons concentrated mostly in the months from June to October. The average occurrence number in those months ranged from 3.9 to 5.5 based on 30 years of record(1971-2000). However, the numbers increased from 4.0 to 6.2 during the most recent 10 years(1991-2000). Jeju province, among others in Korea, was most frequently affected by typhoon which occurred 23 times during the period of 1991-2000. Typhoons which occurred from July to early August have passed mostly through the west of Jeju, whereas, those of late August to September have passed through the center and eastern sea area of Jeju. The typhoons 'Ramasun' and 'Rusa' caused severe damage in Jeju area in September 2003 and the surge heights were +39cm and +77cm, respectively. The main cause of the damage was surge height which was highly associated with the tidal phase at the time of typhoon passage. The damage caused by typhoon on the aquaculture, fishing boat and harbor cosatline wall around Jeju Island which was amounted to be 417 billion won(\) during the recent 3 years(2002-2004)