• Journal of Korea Water Resources Association
• /
• v.45 no.12
• /
• pp.1275-1292
• /
• 2012

This study investigates the characteristics of stem waves along a vertical structure under overtopping conditions through laboratory experiments in a wave basin. The uni-directional random waves with Bretschneider-Mitsuyasu frequency spectrum as incident waves were used. This study is focused on the reduction of wave height due to the variation of relative freeboard height (R) and the results for wave overtopping conditions are compared with those for non-overtopping conditions. Though the relative wave height along a vertical structure decreases with the decrease of relative freeboard, the variation of stem width is not significant. For the relative freeboard is greater than 1, the reduction effect of stem wave height by overtopping can be ignored in this experiments. The reduction effect of wave height along the structure for R =0.5 is about 10% comparing with R =1.5.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.36 no.1
• /
• pp.1-10
• /
• 2024

As increasing demands for a floating structure expanded from offshore industry facilities to living facilities, it has emerged that necessity of techniques to reduce motions of a floating structure. This study present a floating structure with porosity on the outer surface of the floater. Under each regular and irregular wave, responses of the floater was investigated in frequency domain. The proposed structure is composed of inner and outer floaters, which are connected to each other and the outer wall is perforated, and the heave and the pitch of floaters with different perforation rates (0~30%) were compared with at both the center and the edge. The results showed that pitch responses can be decreased by increasing of perforation rate of the floater. Comparing with responses of the non-perforated floater, those of the proposed floating structure were reduced to above 10% and 2%, respectively for regular and irregular wave conditions.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2004.08a
• /
• pp.273-276
• /
• 2004

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2004.08a
• /
• pp.114-121
• /
• 2004

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2008.09a
• /
• pp.240-243
• /
• 2008

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2008.09b
• /
• pp.240-243
• /
• 2008

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 1994.07a
• /
• pp.2-7
• /
• 1994

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.18 no.2
• /
• pp.153-159
• /
• 2012

This study gives the vertical motion analysis in multi-directional irregular waves using a commercial code(MAXSURF v.16) based on linear strip theory for a training ship. To verify the commercial code prior to the analysis, we guarantees the reliability of this paper's results using the commercial code by comparing with the results(Flokstra, 1974) of same hull and experimental conditions on a Panamax container. The analysis conditions are Beaufort wind scale No. 5($\bar{T}=5.46$, $H_{1/3}=2m$) based on ITTC wave spectrum, encounter angle Head & bow seas($150^{\circ}$) and Froude number Fn=0.257. Finally, we calculates heave RAO, pitch RAO and obtains the result of ship's response spectra for heave and pitch motions. In the motion response spectrum under the multi-directional irregular waves, heave motion reacts slightly high in short-crested waves and pitch motion reacts high in long-crested waves.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.32 no.2
• /
• pp.122-134
• /
• 2020

On the many coasts of South Korea, including the eastern side, it has been recently increasing the coastal disaster such as the severe coastal erosion and road damage swept away by the wave. As one of the alternatives to prevent the coastal disaster, it has been widely studied the coastal disaster reduction method by the Low-Crested Structure (LCS) in the many countries including several European countries. In this study, the olaFLow model is used to simulate the permeable LCS and wave field of the LCS through the three-dimensional irregular waves numerical analysis on the basis of the previous research. From the numerical analysis, it is evaluated the H_rms, nearshore current and time-averaged turbulent kinetic energy. In addition, the pattern of nearshore current and spatial distribution of time-averaged turbulent kinetic energy are compared with the case of submerged breakwater under the irregular wave fields. As one of significant results, it is confirmed that the pattern of nearshore current is different with the case of submerged breakwater.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2018.05a
• /
• pp.197-198
• /
• 2018

In recent years, diversified demand for marine utilization has been increasing not only through the development projects for the utilization of the conventional coastal zone but also by the development of marine leisure sports and marine energy. It is very important to understand the characteristics of blue for safe and economical utilization of the ocean. Using the observed wave data, we derive the wave parameters to represent the irregular sea state proposed in the previous studies and examine the relationship between them to confirm the characteristics of the ocean wave.