• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.3
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• pp.178-189
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• 2004

For designing a reliable harbor, a methodology for estimating design waves of 97.5% operable harbor condition is suggested using long-term wave data. For a practical application of the methodology, a marine police harbor was selected as a site. Wave data used were collected from February 1993 to December 2003 at Jodo wave gage station in front of Pusan harbor. Joint distributions of significant wave height and significant wave period for specified wave directions were obtained and used to feed as input waves for parabolic mild-slope wave model. Results showed that input waves with significant wave height of 1.75 m, significant wave period off sec and wave direction E yield design waves height of 1.06 m at the site of interests, which is a 97.5% operable harbor condition. Wind waves generated inside harbor showed to be no effect on the design wave condition. Swells propagated from deep water into harbor are shown to be dominant effects on the design waves of operable harbor condition.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.333-342
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• 2017

In order to understand the mechanism of the cross-shore evolution of storm (barred) and normal (nonbarred) profiles of a sandy beach, the vertically two-dimensional laboratory experiment was performed with a movable bed. The beach profiles and free surface motion were measured under monochromatic wave conditions evolving the storm and normal beach profiles. The observation was conducted in the surf zone during the alternation of the two wave conditions to reach its quasi-equilibrium state. The sandbar-crest and trough and the steep berm were evolved due to the plunging breakers in the storm case, and the bar-trough was decayed due to the spilling breakers in the normal case. From the measurements, it was found that the storm wave case was in an erosion state and the normal wave case was in an accretion state. The strong undertow, which is a dominant factor of the offshore migration mechanism, was developed in the storm wave case, and the weak undertow was developed in the normal wave case. The skewness and the asymmetry of the nonlinear wave motion, which is a dominant factor of the onshore migration mechanism, was measured similarly in both cases.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.637-644
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• 2015

In order to estimate harbor tranquility, it is needed to simulate wave propagation in a harbor by using both methods under abnormal wave condition and normal wave condition. The problem is the latter case was not simulated in the statement for the Sea Area Utilization Conference. As harbor calmness about normal wave condition has the same meaning as harbor serviceability, in order to assess harbor tranquility, it is needed to survey wave data for long periods but the survey was not done by reason of a lack of budget and shortage of time for plan. It is more important to make a plan for minimizing environmental impact and to assess an improvement of fisherman's living environmental as the assessment of the harbor serviceability is related with the propriety of the plan. In order to assess it, it is needed to understand it clearly, survey for long period of wave data, and clarify the procedure for computation of it. And also providing wave data like tide and tidal current data from KHOA (Korea Hydro graphic and Oceanographic Agency) and making a guideline for assessing it are needed.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1993.07a
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• pp.34-37
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• 1993

지금까지의 항만정온도 평가시에는 주로 회귀연도 50연의 설계파를 입사파로 사용하여 대상수역에서의 파고비를 구한 후 평상시의 파랑에 대해서도 이 비율이 선형적으로 적용 가능한 것으로 가정하고 사용하였다. 그러나, 설계액와 평상시 파랑은 주기외 파고가 달라서 파랑경사가 다르므로 위와 같이 파고비가 선형적으로 비례한다고 가정하는 것은 실제와 상당한 차이를 야기시킬 수 있다. (중략)

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.663-671
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• 2013

The width of Haeundae beach has been decreasing annually due to the loss of sand from land, high waves, reflected waves, etc.. The accurate prediction of wave-induced currents is indispensible to analyze the beach deformation due to the sediment transport. In the this study, Numerical experiments were performed with seasonal representative wave on the basis of a long term and comprehensive survey data. In summer, we found the deposition of Mipo by longshore current eastly by ordinary and S waves, and in winter, the deposition of Dongback-island by longshore current westly by ordinary and E waves. In addition, rip current occurs in the middle of Haeundae beach by 50 year return period wave and current westly along the coast by ESE directional wave.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1997.10a
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• pp.120-124
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• 1997

최근까지의 국내 신항만 설계시에는 50년 빈도 심해파나 평상파 조건을 사용한 이상시 및 평상시 항내정온도 검토는 수행되었으나 파랑에 의한 연중가동율 추산은 과학기술처(1993)의 연구에서 동해항을 대상으로만 실시되었다. 본 연구에서는 부산 신항(그림 1 참조)의 연중가동율을 수치실험과 3차원 수리모형실험에 의해 추정한 결과를 제시한다. (중략)

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.4
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• pp.195-202
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• 2000

Recently, wave dissipating structures with porosity are widely used to improve habor tranquility and to reduce the wave overtopping rate. In this study, hydraulic model tests were performed to examine hydraulic efficiency of slit caissons, igloo blocks, and hollow blocks. The model tests showed that slit caissons were the most effective in dissipating wave energy under moderate wave conditions. Slit caissons and igloo blocks showed no significant difference in reducing wave overtopping rate. Hallow blocks are less effective in reducing wave overtopping rate than slit caissons and igloo blocks lU1der higher wave energy conditions.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.4
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• pp.266-273
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• 2016

Two-dimensional hydraulic experiments were performed to assess the impact of artificial seaweed on wave energy attenuation, and coastal erosion prevention. In this experimental study, erosion geometry and wave reflection coefficients were determined for normal and stormy incident waves, with and without artificial seaweed. The coastline of beaches without artificial vegetation was observed to retreat, and the longshore bar height increased in normal and stormy conditions. Through the introduction of artificial seaweed (of widths 0.8 m, and 1.6 m), the coastline was found to advance in the offshore direction due to material deposition. From these results, it is shown that artificial seaweed alters the cross-section of beaches, such that it is possible to prevent coastline erosion.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.2109-2112
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• 2007

독도는 울릉도에서도 동남쪽으로 약 87.4km 떨어져 외해의 영향을 많이 받고 있는 지역이지만 방파제 등 외곽시설이 전무하여 평상파랑에도 접안이 어려운 경우가 많아서 독도 관광자원 활용도 및 편의시설 제공면에서 많은 어려움이 있다. 이에 본 연구에서는 독도 접안시설의 전면에 최근 국내에 본격적으로 도입되고 있는 부방파제(floating breakwater)를 설치할 경우 고정식 방파제 설치에 따른 문제점을 충분히 개선할 수 있다고 판단하여, 부방파제 설치에 따른 기술적인 타당성과 부두 이용률 개선효과 등을 연구 하였다. 독도의 접안시설은 해역이 동도와 서도에 의해 북쪽은 일부 차폐되고 남쪽은 직접 노출되어 있는 지리적 특성이 있어 주 파향인 남쪽계열의 8개 파향(SE, SSE, S, SW, SSW, WSW, W, WNW)의 평상파 제어가 가능하도록 방파제를 배치하였고, 이에 따른 부두 이용률 검토결과 부방파제를 설치할 경우 남쪽계열 파랑에 대하여 현상태에 비하여 부두 이용률이 대략 2배정도 증가되는 것으로 나타났으며, 부방파제 계류시스템의 안정에 대해서도 부체에 영향을 주는 외력에 대하여 계류체인의 길이와 Anchor Block 자중의 규모를 적당히 조정하면 충분히 안정한 것으로 검토되었다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.585-594
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• 2013

In this study, laboratory experiments and numerical simulations were conducted to test the performance of resonance power buoy system proposed by Kweon et al.(2010). The system is composed of a linear generator and a mooring buoy. The mover of the linear generator mainly has heave motion driven by vertical oscillation of the buoy. In this system, the velocity discrepancy between the mover and the buoy makes electricity. However, ocean wave energy as a natural resource around Korean peninsula is comparatively small and the driving force for producing electricity is not enough for commercialization. Therefore, it is necessary that the buoy motion be amplified by using resonance characteristics. In order to verify the resonance effects on the test power buoy, the experimental investigations were conducted in the large wave flume (length of 110 m, width of 8 m, maximum depth of 6 m) equipped with regular and random plunger wave generator. The resonance draft of test power buoy is designed for the corresponding period of incident wave, 1.96 sec. Regular wave test results show that the heave response amplitude operator(RAO) by a test buoy has the amplification of 5.66 times higher compared to the wave amplitude at the resonance period. Test results of random waves show that the buoy has the largest spectrum area of 20.73 times higher at the point of not the resonance period but the shorter one of 1.85 sec. Therefore this study suggests the resonance power buoy for wave power generation for commercial application in the case of the coastal and oceanic area with smaller wave energy.