DOI QR코드

DOI QR Code

Numerical Model Experiments of Wave Transformation for the Marine Structure Design

해양구조물 설계를 위한 파랑변형 수치모형실험

  • 장호식 (경남도립남해대학 조선토목계열)
  • Received : 2011.11.03
  • Accepted : 2011.12.02
  • Published : 2012.03.31

Abstract

Numerical model experiments of wave transformation due to the reclamation and the construction of breakwater in case of 50 years design wave were performed using time dependent mild slope equation included shoaling, refraction, diffraction, reflection and wave breaking. As waves propagate to the shore, wave height gradually diminishes by the bottom friction and wave breaking etc.. After the reclamation and the construction of 75 m length breakwater, wave height distributions in the lee of breakwater have the range of 29~128 cm. To make better the harbor tranquility the length of breakwater needs to extend more than 100 m. After the construction of breakwater, wave height in the lee of the structure was deduced over 80%.

천수변형, 굴절, 회절, 반사, 쇄파에 의한 에너지감쇠를 모두 고려한 시간의존완경사방정식을 이용하여 50년 빈도 설계파 내습시 매립과 방파제 설치에 따른 파랑변형 수치실험을 수행하였다. 항의 입구에서 입사되는 파랑은 만내부로 진입하는 과정에서 바닥에 의한 에너지 감쇠와 쇄파 작용 등으로 인해 파고의 점진적 감소가 나타났다. 매립후 75 m의 방파제를 설치하였을 경우 방파제 배후에서 파고분포는 29~128 cm 범위로 일부 해역에서 항만 정온도가 확보되는 것으로 나타났다. 보다 넓은 해역에서 정온도를 확보하기 위해서는 방파제의 길이를 100 m 이상 확장하는 것이 타당할 것으로 판단된다. 그리고, 방파제를 설치하였을 경우 방파제 배후에서 파고는 80% 이상 감소하였다.

Keywords

References

  1. Liu, P.L.-F., Boissevain, P.L., Ebersole, B.A. and Kraus, N.C., "Annotated bibliography on combined wave refraction and diffraction", miscellaneous CERC Rep. No. 86, 1986.
  2. Nowgu, O., "Alternative form of Boussinesq equations for nearshore wave propagation", J. Waterway, Port, Coastal and Ocean Engineering, 119, 618-638, 1993. https://doi.org/10.1061/(ASCE)0733-950X(1993)119:6(618)
  3. Liu, P.L.-F., "Model equations for wave propagations from deep to shallow water", Advances in Coastal and Ocean Engineering Science, P.L.-F. Liu, ed., 1, World Scientific, pp.125-157, 1994.
  4. Berkhoff, J.C.W., "Computation of combined refraction-diffraction", Proc. 13th Coastal Eng. Conf., 1, pp.471-490, 1972.
  5. Massel, S.R., "Extended refraction-diffraction equation for surface waves", Coastal Engineering, p.19, pp.97-126, 1993. https://doi.org/10.1016/0378-3839(93)90020-9
  6. Chamberlain, P.G. and Porter, D., "The modified mild-slope equation", J. Fluid Mechanics, p.291, pp.393-407, 1995. https://doi.org/10.1017/S0022112095002758
  7. Smith, R. and Sprinks, T., "Scattering of surface waves by a conical island", J. Fluid Mechanics, p.72, pp.373-384, 1975. https://doi.org/10.1017/S0022112075003424
  8. Kirby, J.T., "A general wave equation for waves over riffle beds", J. Fluid Mechanics, p.162, pp.171-186, 1986. https://doi.org/10.1017/S0022112086001994
  9. Ito, Y. and Tanimoto, K., "A numerical wave analysis method and its application", Proc. 18th Japanese Conf. on Coastal Eng., JSCE, pp. 67-70 (in Japanese), 1971.
  10. Copeland, G.J.M., "A numerical model for the propagation of short gravity waves and the resulting circulation around nearshore structures", Doctoral thesis, University of Liverpool, 1985.
  11. Watanabe, A. and Maruyama, K., "Numerical modeling of nearshore wave field under combined refraction", diffraction and breaking, Coastal Eng. in Japan, p.29, pp.19-39, 1986.
  12. 合田良實, 碎波指標の整理について, 土木學會論文報告書集, 第180号, pp.39-49, 1970.