• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.1
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• pp.36-45
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• 2017

In the present study, the storm waves at the Korean Straits of April, 2016 have been reproduced by the wave hindcasting, and then their characteristics were investigated. Before the wave hindcasting, the wave measurements at the Korean Straits were analyzed. The analysis showed that the waves at the Korean Straits were dominated by the Northeastern waves, same as those in the East Sea. Accordingly, the wave hindcasting was been carried out with the same condition in Ahn et al. (2016). In the numerical results, the maximum significant wave height at the Korean Straits was 5.06 m, and the corresponding significant wave period was 9.2 s. The computed significant wave heights and wave periods were overestimated by 4 cm and 0.8 s, respectively. After the wave hindcasting, the computed significant wave heights and peak periods were compared with the JONSWAP relationship. This comparison showed that the storm waves at the Korean Straits were close to wind waves, not swell.

• Journal of Ocean Engineering and Technology
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• v.29 no.1
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• pp.62-69
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• 2015

Coastlines are protected by breakwater structures against the erosion of sand or other materials along beaches due to wave action. This research examined the use of physical modeling to determine the effects of the tetrapod size and vertical walls of a rubble mound on the volume of wave overtopping under irregular wave conditions in coastal areas in Busan Yacht Harbor. In this analysis model, the structures were studied using irregular waves and the JONSWAP wave energy spectrum. To understand the effects of the tetrapod size and heights of the vertical wall, the study considered vertical walls of 0, 1.78, 6.83, and 9.33 cm with armor double layered material tetrapods of 8, 12, 16, and 20 tons. An extensive number of experiments covering a relatively large range of variables enabled a comprehensive discussion. First, in the presence of a short vertical wall, the water level played a key role in the overtopping discharge. In such circumstances, the values of the wave overtopping discharge decreased with increasing freeboard size. In the presence of a tall freeboard and middle, the value of the wave overtopping discharge was equally influenced by the vertical wall factor. Moreover, the tetrapod size decreased by an increase in the vertical wall factor, and relationship between them resulted in a short wall height. From an engineering point of view, considering a small water level may allow the choice of a shorter vertical wall, which would ultimately provide a more economical design.