2020 Volume 76 Issue 2 Pages I_73-I_78
On estimating reliable harbor tranquility in the port of which a part of offshore composite breakwaters has sunk in a sea, it must be required to calculate wave transformation on and behind the submerged caisson-type breakwater instead of the missed composite breakwater. In this study, the harbor tranquility analysis is conducted by using a Boussinesq-type wave model which can consider wave fission, refraction and breaking on a sea-bed gap to estimate cargo handling rates on a target berth in cases of the submerged breakwater existing and the offshore breakwater missing.
In case that the top of breakwater near the harbor entrance has sunk by 2 meters below the sea level, the wave period of transmitted wave is shortened by about 20% in a relative wide area behind the submerged breakwater due to wave fission while the incident wave height is 1 meter. In addition, the cargo handling rate in the case of the submerged breakwater existing is at least 10% higher than one of the offshore breakwater missing because of reduction of wave heights due to breaking, and so on.
