• Journal of Advanced Marine Engineering and Technology
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• 제33권6호
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• pp.965-974
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• 2009

The current study reviews the formula used to calculate the stability of an artificial reef in the breaking wave zone of coastal waters. A comparison was carried out between the existing formula and a new formula that takes into account the water particle velocity in the breaking wave zone. Water particle velocity was analyzed using the Fluent (CADMAS-SURF) software program. The new formula took into various factors, including the difference in the drag coefficient due to the direction of the current and the ratio of distance between two reefs. The drag coefficient of the artificial reef due to the direction of the current was 0.84 when the distance ratio was 0.5. When the artificial reef was placed at 45 degree angle to the current, the product of the drag coefficient and the project area were 40 to 46 % greater than when the reef was placed at 90 degree angle. Our results regarding the stability of an artificial reef indicate that the new formula provides the designers of artificial reefs with a more rational and economic design rationale rather than the existing formula.

• 한국해양공학회지
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• 제21권5호
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• pp.61-67
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• 2007

As part of the government's fishery resource creation policy, fishing ground creation projects have been undertaken in Korea's major seashore fishing spots since the 1970s, where artificial reefs constructed using new materials that make up for the weakness of concrete reefs have been used. In this study, the stability of these artificial reefs when acted upon by external forces, their ability to attract and gather fish, and their economic feasibility were examined. For this purpose, an experimental artificial steel reef was constructed and was installed in an area of the sea. Then the corrosion of the experimental material attached to it was investigated. The efficiency of the artificial steel reef was then verified by examining its functionality, removal, and burying, as well as the speed of insertion of living things into its structure and its ability to attract and gather fish.

• 한국해양공학회지
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• 제24권2호
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• pp.18-24
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• 2010

Submerged rubble structures include artificial reef and the mound part of the rubble mound breakwater. Artificial reef is a type of the submerged wave absorbing structure installed in a coastal zone to prevent beach erosion and designed to initially reduce the energy of incoming waves so that its run-up height and overtopping quantity can be decreased. In order to ascertain the stability of such submerged rubble structures, minimum weight of the rubble has to be calculated first from the incoming wave height using Hudson's formula or Brebner-Donnelly formula. Based on the calculated minimum weight, a model is built for use in a hydraulic model test carried out to check its stability. The foregoing two formulas used to calculate the minimum weight are empirically derived formulas based on the result of the tests on the rubble mound breakwater and it is, therefore, difficult for us to apply them directly in the calculation of the minimum weight of the submerged structures. Accordingly, this study comes up with a numerical simulation method capable of deformation analysis for rubble structures. This study also tries to identify the deformation mechanism of the submerged rubble structures using the numerical simulation. The method researched through this study will be sufficient for use for usual preparations of the design guidelines for submerged rubble structures.

• 해양환경안전학회지
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• 제24권5호
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• pp.537-544
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• 2018

본 연구에서는 해수 중 유체력에 의한 인공어초의 활동 및 전도를 평가하기 위한 간편하고 효율적인 사용자 중심의 전산 프로그램(SCAR program)을 개발하였다. 개발된 전산 프로그램은 인공어초의 안정성 평가 공식인 모리슨(Morison) 식을 기반으로 델파이(Delphi) 코드 및 그래픽 사용자 인터페이스(GUI, Graphic User Interface) 방식을 적용하였다. 개발된 SCAR 프로그램은 학부 및 대학원 과정, 실제 현장 전문가들의 수산구조물(인공어초 또는 수중구조물 등) 설계 및 안정성 평가에 널리 적용 가능할 것으로 판단된다.

• 한국해양공학회지
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• 제35권1호
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• pp.75-81
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• 2021

Artificial Coral Reefs (ACRs) have been introduced to help solve coastal erosion problems, but their feasibility has not been assessed with field data. This study conducted a feasibility analysis of ACRs on their erosion mitigation effects by performing a case study of Cheonjin-Bongpo beach, South Korea. A numerical-physical combined analysis was carried out using a SWAN model simulation and physical model test with a scale of 1/25 based on field observations of Cheonjin-Bongpo beach. Both Dean's parameter and the surf-scaling parameter were applied to comparative analysis between the absence and presence conditions of the ACR. The results for this combined method indicate that ACR attenuates the wave height significantly (59~71%). Furthermore, ACR helps decrease the mass flux (~50%), undertow (~80%), and maximum wave set up (~61%). The decreases in Dean's parameter (~66%) and the surf-scaling parameter suggest that the wave properties changed from the dissipative type to the reflective type even under high wave conditions. Consequently, an ACR can enhance shoreline stability.

• 수산해양교육연구
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• 제28권3호
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• pp.630-644
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• 2016

We conducted a comprehensive review on artificial reefs (ARs) including seaweed reefs for marine afforestation in relation to their development and research from 1972 to 2016, and then systematically analyzed their current a state-of-the-art and practice. From the review, the followings conclusions are made. First, the objectives of AR projects in the Southeast Asia can be classified into three, i.e. protection and increase of fishery resources, local community's profits, and ecological tourism. Second, fish gathering effects by ARs can be determined in terms of wake region or wake length that tends to increase with the K-C (Keulegan-Carpenter) number. Third, ARs are desirable to deploy across a direction of the main flow but it is essential to keep the deployment interval two to four times the length of a single reef. Fourth, stability of ARs depends on how to evaluate drag coefficient, and Morison formula turns out to be practical. Fifth, local scours of ARs are likely to occur due to a downward flow around the center of the front surface. Finally, it is natural for ARs to positively contribute to the marine ecosystem but it is imperative to develop an evaluation method for the effects of ARs on the marine ecosystem.