KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
권호 표지
DOI QR코드

DOI QR Code

Experimental Study on Irregular Wave Forces Acting on a Marker Rock Installed on a Submerged Breakwater

수중방파제 천단상의 표식암에 작용하는 불규칙파의 파력특성에 관한 실험적 연구

  • 허동수 (경상대학교 토목환경공학부(해양산업연구소))
  • Received : 2006.02.08
  • Accepted : 2006.04.24
  • Published : 2006.07.31
Download PDF
⟨ Previous Next ⟩

Abstract

The construction of a submerged breakwater has become increasing due to their multiple effects on the coastal zone. Recently, marker rocks have been installed on the submerged breakwater to indicate its position to the vessels instead of buoy systems, since a buoy is not only improper for the ocean view, but also its mooring system may be damaged by the impulsive wave force caused by wave breaking on the breakwater. The accurate estimation of wave forces on such rocks is deemed necessary for their stability design. In this study, the characteristics of irregular wave forces acting on a marker rock, which was installed on a submerged breakwater, was investigated on the basis of laboratory experiments. It was revealed that the dimensionless highest one-third wave force tends to decrease with increasing the installation distance of a marker rock from the leading crown edge of a submerged breakwater. Also, the drag and inertia coefficients for irregular wave forces, which were obtained using the Morison equation, were investigated in relation to K.C. number.

연안역에 설치되는 구조물로서 경관이나 해수 교환면에서 높은 기능을 가지고 있는 수중방파제의 건설이 증가하고 있다. 수중방파제의 경우, 천단이 정수면 아래에 위치하기 때문에 소형선박의 항해에 대한 표식으로서 일반적으로 부이가 많이 이용되고 있으나, 경관면 뿐만 아니라 쇄파파력에 의한 계류시스템의 파단과 같은 문제점이 지적되고 있다. 이로 인해, 최근에는 계류부이방식 대신에 자연에 가까운 경관을 창조할 수 있는 표식암을 이용하는 경우가 늘고 있으며, 이러한 표식암에 작용하는 파력의 정확한 예측은 설계 시 매우 중요하다. 본 연구에서는 불규칙 파동장을 대상으로 표식암에 작용하는 파력특성을 수리모형실험에 근거하여 검토하였다. 무차원 파력은 수중방파제상의 표식암 설치위치가 연안측으로 이동함에 따라 감소하는 경향을 보였다. 또한, Morison식을 이용하여 얻어진 항력계수와 관성력계수의 변동특성이 K.C.수의 변화와 연관되어 논의되었다.

Keywords

References

  1. 배기성, 허동수(2002) 잠제상에 설치된 표식암(의암)에 작용하는 규칙파파력의 실험적 연구, 한국해양공학회지, 한국해양공학회, 제16권 제6호, pp. 7-17
  2. Goda, Y., Haranaka, S., and Kitahata, M. (1966) Study of impulsive breaking wave forces on piles, Rept. Port and Harbour Res. Inst., Vol. 5, No. 6, pp. 30. (in Japanese)
  3. Goda, Y, Ikeda, T, Sasada, T., and Kishira, Y. (1972) Study on design wave forces on circular cylinders erected upon reefs, Rept. Port and Harbour Res. Inst., Vol. 11, No. 4, pp. 45-81. (in Japanese)
  4. Hall, M.A. (1958) Laboratory study of breaking wave forces on piles, TM-106, U.S. Army, Corps of Engineers, Reach Erosion Board, Washington D.C
  5. Horikawa, K., Watanabe, A., and Katsui, H. (1973) Breaking wave forces acting on circular cylinders, Proc. 20th Japanese Conf. on Coastal Eng., pp. 37-42 (in Japanese)
  6. Hur, D.S. and Mizutani, N. (2003) Numerical estimation of the wave forces acting on a three-dimensional body on submerged breakwater, Coastal Engrg., Vol. 47, pp. 329-345 https://doi.org/10.1016/S0378-3839(02)00128-X
  7. Hur, D.S., Mizutani, N., and Kim, D.S. (2004) Direct 3-D numerical simulation of wave forces on asymmetric structures, Coastal Engrg., Vol. 51, pp. 407-420 https://doi.org/10.1016/j.coastaleng.2004.05.003
  8. Keulegan, G.H. and Carpenter, L.H. (1958) Forces on cylinder and plates in an oscillating fluid, J. Res. Nat. Bur. Stand., Vol. 60, No. 5, pp. 423-440 https://doi.org/10.6028/jres.060.043
  9. Mitsuyasu, H. and Honda, T. (1973) Breaking wave forces on circular piles, Proc. 20th Japanese Conf. on Coastal Eng., pp. 43-47. (in Japanese)
  10. Mizutani, N. (1994) Estimation method of wave forces on a submerged sphere, J. Japan Society of Civil Engineers, Vol. 497, pp. 91-100. (in Japanese)
  11. Morison, J.R., OBrien, M.P., Johnson, J.W., and Schaaf, S.A. (1950) The wave force exerted by surface wave on piles, Petroleum Trans, AIME, Vol. 189, pp. 149-157
  12. Ross, C.W. (1955) Laboratory study of shock pressures of breaking waves, TM-59, U.S. Army Corps of Engineers, Beach Erosion Board, Washington D.C
  13. Ross, C.W. (1959) Large-scale tests of wave forces on piling, TM-111, U.S. Army Corps of Engineers, Beach Erosion Board, Washington D.C
  14. Sarpkaya, T. and Isaacson, M.Q. (1981) Mechanics of Wave Forces on Offshore Structures, Van Nostrand Reinhold, New York, 651 p
  15. Sawaragi, T., Nochino, M., and Iwahashi, T. (1983) On characteristics of partial impulsive breaking wave forces and total wave forces on circular piles in shallow water, Proc. 30th Japanese Conf. on Coastal Eng., pp. 376-380. (in Japanese)