• Journal of Ocean Engineering and Technology
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• v.16 no.1
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• pp.22-26
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• 2002

In this paper, a finite element method is applied to the numerical calculation of the harbor calmness. The mild stop equation as the basic equation is used. The key of this model is that the bottom friction and boundary absorption are imposed. A numerical result is presented and compared with the results obtained from the other numerical analysis. These results are in very well agreement. This method calculating the calmness can be broadly utilized making the new design of harbor and fishing port in the future.

• 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.

• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.673-681
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• 2014

Due to the increased demand for safety and security requirements on the port infrastructure, the harbor tranquility is one of the important parameter in the mooring basin of harbor. It relates keenly to berthing/unberthing and cargo handling works but also it is an important indicator to get the minimum water area as the safe refuge. Hupo harbor is a national coastal harbor located in east coast of Korea and a development plan for a new marina near the entrance is being carried out including berth layouts, breakwater extensions, 300m marina berths, dredging and land reclamation works. The new plan will impact on calmness of the existing port. Therefore, it is necessary to analyze in complex the variation of wave height and direction caused by wave refraction, diffraction, shoaling and reflection from the incident waves from outside the harbor. In order to check the calmness inside a harbor, the numerical models are being used currently need fundamental reviews according to the difference of results which depend on their respective features. In this study, hence, it was introduced the validity of numerical models by comparing the computational results with the hydraulic model experiment. The current investigations contribute to the existing development recommendations and provide further solutions for port planning.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.255-257
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• 2014

The harbor tranquility is indicating the level of calmness in the mooring basin of harbor. It relates keenly to berthing/unberthing and cargo handling works but also it is an important indicator to get the minimum water area as the safe refuge. Therefore, it is necessary to analyze in complex the variation of wave height and direction caused by wave refraction, diffraction, shoaling and reflection from the incident waves from outside the harbor. In order to check the calmness inside a harbor, the numerical models are being used currently need fundamental reviews according to the difference of results which depend on their respective features. In this study, hence, it was introduced the validity of numerical models by comparing the computational results for Hupo harbor.

• Journal of Ocean Engineering and Technology
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• v.17 no.1
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• pp.16-20
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• 2003

본 연구에서는 입사파에 의한 항내 정온도 계산 시 사용되는 수치해석 기법에 대한 검증 및 실제 항만에 대한 적용을 하였다. 해석기법은 유한요소기법 (finite element technique) 을 사용하였고 기본방정식은 경계조건과 마찰을 고려한 완경사방정식 (mild-slope equation) 을 사용하였다. 해석의 검증을 위하여 임의형상 항만에 대해 본 해석법을 적용하여 수치해석을 실시한 결과와 다른 수치해석결과 및 실험결과를 비교했을 때 좋은 일치를 나타내었다. 제주항에 대해서 2가지의 각기 다른 입사파 조건을 적용하여 계산한 결과 제주항이 방파제 설계파인 NNW방향 (Case 2)인 경우가 NE 방향 (Case 1)인 경우보다 약간 양호한 정온을 확보하는 것을 알 수 있었다.

• Journal of Ocean Engineering and Technology
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• v.16 no.2
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• pp.21-26
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• 2002

In this study, the characteristics of long period waves are analyzed by field observation at Sokcho harbor on the eastern coast of Korea. firstly. the pressure data obtained from field observation are transformed into water surface elevations and the wave by wave analysis is applied to the observed wave data. also, we select long period waves by setting up the range 30-200sec, and suggest the relationship between ordinary waves and long period waves using the concept of the significant wave height. and, we examine the effects oft he long period waves on the rate of the harbor operation. The observation results demonstrate that the long period waves with heights of 1.2-14.6cm and periods of 35.8-162sec exist at Sokcho harbor. also, we found the rates of harbor operation based on long period waves are 61.8%-99.5% lower than the usual rates of 93.8%-100%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6B
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• pp.651-660
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• 2006

Although a harbor may be constructed with calmness in harbor in mind, which satisfies the design standard, it is frequently reported that the motion of moored ships disrupt the cargo handling. This is because of current design standard, which only deals with the wave height in the decision making process of cargo handling, and, now, a new kind of estimation method of operating ratio for calmness based on the motion of moored ship is in need. In this research, a computational method that analyses the harbor operation rate in harbor was put forward by considering the relation of allowable quantity of motion for cargo handling and the computation of the motion of moored ship at wharf by using moored ship motion analysis model. Here, a new estimetion method was applied at Onsan harbor, and it was compared with the current estimation method, and, then, the difference between the two methods was showed. The harbor operating ratio gained by a new method was dropped by 2~11% at ENE and NE directions when it was compared with the operating ratio based on the current design standard. However, when a harbor structure layout is to be designed, a harbor operating ratio test according to the wave height and a harbor operation rate test, which considers the motion of moored ship, are to be run side by side at a harbor designing process.

• Journal of Navigation and Port Research
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• v.34 no.9
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• pp.711-718
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• 2010

Redevelopment of the domestic small fishing ports is being started in earnest by applying the environmentally friendly technology in order to attract tourists. For the purpose of improving water quality in the harbor, selection of breakwater type might have the priority to secure calmness and stability. Therefore, this study is to determine the hydraulic characteristics of reflective ratio, installation efficiency and stability of the special type of blocks through the hydraulic model experiment. The results were introduced to analyze for the effect of infield construction work through numerical analysis. Gujora, a small fishing port in southern Korea, is affected by the waves of SSE, S, SSW direction and strong tidal currents. The results of applying cylindrical slit block show that stability of the blocks and harbor calmness were secured. Considering that the pass rate of a long period wave is still excellent, the primary objective of wave control and the secondary objective of improving water exchange are satisfied simultaneously.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.255-263
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• 1992

A numerical simulation using the Boundary Element Method is performed for investigating the seiche in the Mukho harbor. The range of the incident waves period is from 7 seconds to 10 minutes, which these surface waves usually may be found in cases of the swell and the long period storm surges caused by storm winds. It is found that the seiche may be occurred by resonating with the incident waves of which the periods are about 11 seconds and 3 minutes. The numerical method was verified by the hydraulic model experiment data which had performed before. Numerical results for the seiche in the Mukho harbor show good agreements with the field observations, so that this research may be useful to estimate harbor calmness in a harbor and the harbor planning.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.2 no.1
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• pp.18-27
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• 1990

The calmness inside a harbor plays an important role in the appropriate disposition of har-bor structures. However, it is not easy to get the accurate computational results because they are affected by many factors concerning with the wave transformation. Successful solution also depends on determining the boundary values appropriately. This paper presents the numerical model which is able to calculate wave heights inside a harbor It is based upon the time-dependent mild-slope equation involving wave refraction, diffraction, shoaling effect and reflection. In particular, the arbitrary reflectivity is used at the boundary in order to simulate the real harbor reflection condition. This numerical model is applied for Hupo-Harbor and its validities are investgated by comparing with experimental values from the hydraulic model test as well as computational results from Taka-yama's numerical model (1981). It is shown that the model results are in good agreement with results from hydraulic model and Takayama＇s.