Preliminary Study on an amendment to the Design Guideline of Outer Port Facilities Against Harsh Wave Conditions due to Climate Change based on Design Fidelity Index

Abstract

This study aims to develop an amendment to the design guidelines for the outer port facilities based on quantitative indexes to address harsh wave conditions due to climate change. To this end, the author first looked into the in situ data of damage to outer port facilities collected in about a dozen major ports in Korea, where the outer port facility has failed in fulfilling its intended disaster prevention against typhoons over the last decade. In doing so, the design fidelity index, a quantitative index that can rationally determine the scope of reinforcement of outer port facilities, was developed based on the specified failure mechanism. The design fidelity index evaluates the degree of loss of armoring rocks, erosion of main body of breakwater, displacement of cap-concrete, lee side damage by overtopping, and scouring near the toe, which are the primary failure mode of the outer port facilities, and displays these damage extents of each of 5 primary failure mode in polar coordinates. Among the various failure modes mentioned above, scouring near the toe has been found in most outer port facilities, and as a result, the current design practice like whether to install scouring-prevention work is determined based on the limit depth for the incipient sediment motion needs to be revised. Numerical simulation shows that with sediment motion triggered by harsh water surface displacement in the standing waves formed in front of vertical type breakwater being accounted for, the robustness of scouring prevention works, which takes the maximum scour depth as the maximum wave height, could be secured. In addition, among the various quantitative indexes that can provide information concerned with how robust or vulnerable the outer port facilities would be by adjusting design waves return period, it turns out that the increasing rate of failure probability associated with the unit change in the nominal diameter of armoring rocks could provide most promising results.

Development of Probabilistic Models Optimized for Korean Marine Environment Varying from Sea to Sea Based on the Three-parameter Weibull Distribution

“…, 이러한 거동은 파고가 큰 경우 파고와 주기 사이의 상관관계가 옅어진다는 해안공학 계의 정설과는 각을 세우는 것으로 우리나라 해양환경을 담 아낼 수 있는 확률모형 개발이 필요하다는 사실을 방증한다 (Cho and Cho, 2022). 이에 비해 남해안의 경우 가장 거친 해…”

Hydraulic Characteristics of Forced Harmonic Oscillator Constituting Flap-Type Wave Energy Converter: A Numerical Study Using Dynamic Mesh Method (Arbitrary Mesh Interface)

“…The growth of wind waves in the West Sea is also limited by the fetch length due to its elongated shape from north to south. As a result, various wave characteristics are observed along the western and eastern coasts of Korea, unlike in Europe and the United States where long swells predominate (Cho and Cho, 2022). In light of these facts, it can easily be perceived that WEC developed in Europe or the United States cannot be simply deployed in Korea without proper optimization processes.…”

“…However, this approach neglected the nonlinearity of water waves, based on the assumption that its contribution was negligible. A recent study by Cho and Cho (2022) has shown that the nonlinearity of water waves has a significant impact on the wave force, requiring a revision of these design practices. Additionally, numerical analysis based on ideal fluid conditions cannot capture flow separation and the resulting coherent eddies from vortex shedding and boundary layer flow, which can greatly affect the power generation efficiency of WEC.…”

Reliability-based design optimization for a vertical-type breakwater with multiple limit-state equations under Korean marine environments varying from sea to sea

“…Despite the numerous potential applications for reliability-based design, its application in Korea remains somewhat limited 1 – 4 . The limited application of reliability-based design in Korea can be attributed to a lack of comprehensive efforts to integrate the diverse characteristics of the Korean marine environment into the design process 3 , 5 , 6 . This challenge is further compounded by persistent ambiguity surrounding the determination of a righteous return period.…”