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

The Korean Society of Marine Environment and safety (해양환경안전학회)
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A Study on Vortex-Induced Vibration Characteristics of Hydrofoils considering High-order Modes

고차모드를 고려한 수중날개 와류기인 진동특성 연구

  • Choi, Hyun-Gyu (Department of Naval Architecture and Ocean Engineering, Seoul National University) ;
  • Hong, Suk-Yoon (Department of Naval Architecture and Ocean Engineering, Seoul National University) ;
  • Song, Jee-Hun (Department of Naval Architecture and Ocean Engineering, Chonnam National University) ;
  • Jang, Won-Seok (Department of Naval Architecture and Ocean Engineering, Seoul National University) ;
  • Choi, Woen-Sug (Mechanical and Aerospace Engineering, Naval Postgraduate School)
  • 최현규 (서울대학교 조선해양공학과) ;
  • 홍석윤 (서울대학교 조선해양공학과) ;
  • 송지훈 (전남대학교 조선해양공학과) ;
  • 장원석 (서울대학교 조선해양공학과) ;
  • 최원석 (미 해군 기계항공과)
  • Received : 2022.01.28
  • Accepted : 2022.04.27
  • Published : 2022.04.30
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Abstract

Vortex-induced vibration (VIV) occurs owing to the vortex generated from the back side of the appendages of ships and submarines during operation. Recently, the importance of high-order modes (HOMs) vibration and fatigue failure has become increasingly emphasized by increasing the speed of ships and the size of structures. In addition, predicting the vibration of HOMs is significantly necessary as the VIV becomes stronger in the fast flow speed condition than in the low flow speed condition. This study introduces a methodology according to HOMs hybrid Fluid Structure Interaction (FSI) for predicting the HOMs VIV on the hydrofoils. The HOMs FSI system is verified by comparing the VIV results from the FSI simulation with the experimental results. Finally, the effectiveness of the HOMs FSI is determined by applying the maximum von-Mises stress obtained from the VIV on the hydrofoil to the S-N curve released from Det Norske Veritas (DNV). VIV results from the HOMs FSI include the lock-in characteristics as well as a significant increase of more than 10 times compared with that of low-order modes (LOMs) FSI. In the future works, advanced studies will be required for improving cantilever boundary conditions and the shape of hydrofoils.

선박, 잠수함이 추진하면 수중구조물 후류에 와류가 발생하고 이에 따른 와류기인 구조진동이 유발된다. 최근 선박, 잠수함의 고속화 및 대형화 추세에 따라 고차모드에서 유발되는 와류기인 진동 및 피로파괴에 대한 중요성이 강조되고 있다. 고속 유속환경의 와류는 저속 유속환경 대비 큰 진동을 유발하므로 이에 관한 연구가 필요하다. 본 연구에서는 수중날개 고차모드에서 유발되는 와류기인 진동을 예측하기 위한 하이브리드 유체구조연성 해석 방법론을 제시하였다. 고차모드를 고려한 하이브리드 유체구조연성 해석을 수행하여 와류기인 진동을 도출하고 실험결과와 비교함으로써 방법론을 검증하였다. 최종적으로 와류기인 진동으로부터 도출된 최대 von Mises 응력을 노르웨이 선급에서 제시한 S-N 선도에 적용함으로써 고차모드 유체구조연성 해석의 효용성을 확인하였다. 고차모드를 고려하여 와류기인 진동응답을 도출할 경우 유체구조연성에 의한 락인(Lock-in) 특성을 확인하였으며 고려하지 않은 경우 대비 진동응답과 최대 von Mises 응력에서 10배 이상의 차이를 보였다. 향후에는 외팔보 경계조건 및 형상에 대한 확장연구가 필요하다.

Keywords

Acknowledgement

이 연구는 전남대학교 학술연구비(과제번호:2020-3837) 지원을 받아 수행하였습니다.

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