Journal of the Korean Society of Marine Environment & Safety (해양환경안전학회지)

The Korean Society of Marine Environment and safety (해양환경안전학회)
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Optimal Design of Overtopping Wave Energy Converter Substructure based on Smoothed Particle Hydrodynamics and Structural Analysis

SPH 및 구조해석에 기반한 월파수류형 파력발전기 하부구조물 최적 설계

  • Sung-Hwan An (Dept. of Ocean System Engineering, Gyeongsang Nat'l Univ) ;
  • Jong-Hyun Lee (Dept. of Naval Architecture and Ocean Engineering, Gyeongsang Nat'l Univ) ;
  • Geun-Gon Kim (Dept. of Ocean System Engineering, Gyeongsang Nat'l Univ) ;
  • Dong-hoon Kang (Dept. of Naval Architecture and Ocean Engineering, Gyeongsang Nat'l Univ)
  • 안성환 (경상국립대학교 해양시스템공학과) ;
  • 이종현 (경상국립대학교 해양시스템공학과) ;
  • 김근곤 (경상국립대학교 해양시스템공학과) ;
  • 강동훈 (경상국립대학교 해양시스템공학과)
  • Received : 2023.12.06
  • Accepted : 2023.12.29
  • Published : 2023.12.31
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Abstract

OWEC (Overtopping Wave Energy Converter) is a wave power generation system using the wave overtopping. The performance and safety of the OWEC are affected by wave characteristics, such as wave height, period. To mitigate this issue, optimal OWEC designs based on wave characteristics must be investigated. In this study, the environmental conditions along the Ulleungdo coast were used. The hydraulic efficiency of the OWEC was calculated using SPH (Smoothed Particle Hydrodynamics) by comparing 4 models that changed the substructure. As a result, it was possible to change the substructure. Through design optimization, a new truss-type structure, which is a substructure capable of carrying the design load, was proposed. Through a case study using member diameter and thickness as design variables, structural safety was secured under allowable stress conditions. Considering wave load, the natural frequency of the proposed structure was compared with the wave period of the relevant sea area. Harmonic response analysis was performed using wave with a 1-year return period as the load. The proposed substructure had a reduced response magnitude at the same exciting force, and achieved weight reduction of more than 32%.

OWEC(Overtopping Wave Energy Converter)는 월파된 파도를 이용한 파력발전시스템이라한다. OWEC의 성능 및 안전성은 파고, 주기 등 파도의 특성에 의해 영향을 받는다. 따라서 해역 특성에 따른 OWEC의 최적 형상과 구조안전성에 관한 연구가 필요하다. 본 연구에서는 울릉읍 연안 해양 환경 데이터를 이용하였으며, SPH(Smoothed Particle Hydrodynamics) 입자법 해석을 통해 기존 케이슨 하부 구조에 변화를 준 모델 4개를 비교하여 월파 효율을 분석하였다. 그 결과, 하부 구조의 변경 및 경량화가 가능함을 확인하였다. 최적화 해석을 통해 설계 하중에 내하력을 가지는 하부 구조인 새로운 트러스형 구조를 제안하였다. 이후 부재 직경 및 두께를 설계변수로 하는 사례 연구를 통해 허용응력조건 하에서 구조 안전성의 확보를 확인하였다. 주기적인 파랑 하중을 받기 때문에 제안하는 구조의 고유 진동수와 해당 해역의 파주기를 비교하였으며, 1년 재현 주기의 파랑을 하중으로 한 조화응답해석을 수행하였다. 제안하는 하부 구조는 동일 가진력에서 기존 설계 대비 응답의 크기가 감소하였으며, 기존 대비 32% 이상의 중량 절감을 수행하였다.

Keywords

Acknowledgement

이 논문은 2021년도 정부(교육과학기술부)의 재원으로 한국연구재단의 지원을 받아 수행된 연구임(지역대학우수과학자지원사업, No. 2021R1I1A3057230).

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