Journal of Korea Water Resources Association (한국수자원학회논문집)

Korea Water Resources Association (한국수자원학회)
권호 표지
DOI QR코드

DOI QR Code

A Study of Siltation in a Small Harbor

소규모 항만의 퇴사기구에 관한 연구

  • Yoon, Seong-Jin (Research Center for Marine Environment Development & Technology, Kwangdong University) ;
  • Kim, Kyu-Han (Department of Civil and Environmental Engineering, Kwangdong University)
  • 윤성진 (관동대학교 첨단해양공간개발연구센터) ;
  • 김규한 (관동대학교 공과대학 토목공학과)
  • Published : 2006.11.30
Download PDF
⟨ Previous Next ⟩

Abstract

Since a small harbor is often located near surf zone areas which have great influences of sediment transport, there is a great possibility that the sediment will be deposited inside of the harbor. The sediment transport occurring around the harbor entrance can't be explained by the wind wave and wave induced current. In this study, it was investigated the mechanism of the entrainment of sediment into a small harbor with permeable breakwater using hydraulic experiments in 3D wave basin. It is found out that the significant sediment entrainment produced when the mode of oscillation in the harbor became the 1st mode. In the case where the incident wave period was shorter than the period that caused higher mode oscillation in harbor, only a little amount of sediment entrainment took place. The vortex shedding from the top of secondary breakwater played very important roll in the entrainment of sediment into the harbor. It is also found that the small jetty attached at the top of secondary breakwater could effectively prevent the entrainment of sediment into the harbor.

소규모 항만은 주로 쇄파대 근방에 건설되는 경우가 많기 때문에 표사이동에 의한 퇴적영향에 의해 항내매몰이 발생될 가능성이 크다. 본 연구에서는 평면수조를 이용한 수리모형실험을 통해, 투과형방파제를 적절히 설치할 경우에 있어서의 소규모 항만의 항입구부 및 항내로의 표사이동에 대한 메카니즘을 파악하고자 하였다. 우선, 항내의 진동이 1차 모드일 때 표사이동이 증가되는 것을 실험적으로 확인하였다. 또한, 입사파의 주기가 단주기일 경우에는 항내의 진동이 고차 모드가 되고, 항내측으로의 표사이동은 감소되는 경향을 나타내었다. 부(副)방파제 선단에서 발생되는 와류가 항내로의 표사이동의 주된 원인인 것을 확인할 수 있었고, 부방파제 선단 외측에 소돌제를 설치함으로써 와류를 감소시켜 항내로의 표사이동을 억제하는 효과가 있는 것을 확인하였다.

Keywords

References

  1. Deguchi. I., Sawaragi, T., and Ishikawa, H. (1994). 'The Shoaling Transformation of Long-period Wave which is restrained by 2 component wave and the Analysis by Boussinesq Equation,' Proc. Japan Coastal Eng., Vol. 41, pp. 66-70
  2. Lee, J. J. (1971). 'Wave-induced oscillations in harbours of arbitrary geometry,' Journal of Fluid Mechanics, Vol. 45, pp. 375-394 https://doi.org/10.1017/S0022112071000090
  3. Matsumoto, A, Matsuoka, M., Nakayama, A., Yamamoto, J., Nadaoka, K., and Yagi, H. (1993). 'The trial of the long-term continuation observation for a burial mechanism elucidation in a small harbor,' Proc. Japan Coastal Eng., Vol. 40, pp. 491-495
  4. Morita, S., Yoon, S., and Deguchi, I. (2002). 'Study on Ability of Breakwater with Channel to Exchange Water using Wave,' Proc. of Civil Engineering in the Ocean, Vol. 18, pp. 521-526