Ebersole-Type Wave Transformation Model Usiog Extended Mild-Slope Equations

확장형 완경사방정식을 이용한 Ebersole형 파랑변형 모형

  • 정신택 (원광대학교 공과대학 토목환경공학과) ;
  • 이창훈 (한국해양연구소 연안·항만공학연구센터)
  • Published : 1998.12.01

Abstract

Following the approach of Ebersole (1985), water wave transformation is predicted using the eikonal equation and transport equation for wave energy which are reduced from the extended mild-slope equation of Massel (1993), and also the irrotationality of wave number vectors. The higher-order bottom effect terms, i.e., squared bottom slope and bottom curvature, are neglected in the study of Ebersole but are included in the present study. It was expected that, if these terms are included in this study, the approach would give more accurate solution in the case of rapidly varying topography. But, the expectation was frustrated. It is probably because, in the case of rapidly varying topography, the diffraction effect which is included in the eikonal equation does not work well and thus the solution is deteriorated.

Ebersole(1995)의 접근법을 사용하여 Massel(1993)의 확장형 완경사방정식에서 유도되는 eikonal 식과 파랑 에너지전송식과 또한 파수의 비회전성을 이용하여 파랑변형을 예측하였다. 완경사방정식에 무시되었으나 확장형 완경사방정식에 고려된 고차의 수심변화 효과, 즉 수심경사의 제곱 및 수심의 곡률이 고려되면 수심변화가 심한 경우에 더 정확한 해석이 될 것이라는 예측이 수치실험 결과 제대로 나타나지 않았다. 이는 수심변화가 심한 경우 eikonal 식에서 고려된 회절의 효과가 제대로 반영되지 않아서 해석결과에 오류가 발생하는 것이 아닌가 판단된다.

Keywords

References

  1. 대한토목학회논문집(게재 가) 고차의 수심변화 효과가 파랑의 굴절에 미치는 영향 이창훈;윤성범
  2. 한국해안·해양공학회지 v.1 no.1 흐름이 존재하는 완경사 해역에서의 파랑변형 이론적 고찰 채장원;정신택;염기대;안수한
  3. Proc. of 13th Int. Conf. on Coastal Eng. Computation of combined refraction-diffraction Berkhoff, J.C.W.
  4. Coastal Eng. v.7 Verification of numerical wave propagation models for simple harmonic linear water waves Berkhoff, J.C.W.;Booy, N.;Radder, A.C.
  5. Ph.D. Dissertation, Delft Univ. of Technology Gravity Waves on Water with Non uniform Depth and current Booij, N.
  6. Coastal Eng. v.7 A note on the accuracy of the mild slope equation Booij, N.
  7. J. of Fluid Mech. v.291 the modified mild-slope equation Camberlain, P.G.;Porter, D.
  8. J. of Waterway, Port, Coastal and Ocean Eng. v.123 Extended linear refraction-difraction model Chandrasekera, N.C.;Cheung, K.F.
  9. Coastal Eng. v.9 A practical alternative to the mild-slope wave equation Copeland, G.J.M.
  10. J. of Waterway, Port, Coastal and Ocean Eng. v.11 Refraction-diffraction model for linear water waves Eversole, B.A.
  11. Proc. of 13th Int. Conf. on Coastal Eng. A method o fnumerical analysis of wave propagation-application to wave diffractin and refraction- Ito, Y.;Tanimoto, K.
  12. Coastal Eng. v.10 Rational approximations in the parabolic approximation method for water waves Kirby, J.T.
  13. Coastal Eng. v.10 Verification of a parabolic equation for propagation of weakly-nonlinear waves Kirby, J.T.;Dalrymple, R.A.
  14. Proc. of 23rd Int. Conf. on Coastal Eng. Time-dependent mild slope equation for random waves Kubo, Y.;Kotake, Y.;Isobe, M.;Watanabe, A.
  15. Ph.D. Dissertation Univ. of Delaware A Strudy of time-dependent Mild-slope Equations Lee, C.
  16. J. of Korean Society of civil Engrs. v.17 no.2-2 Extended Copeland-type wave equations for rapidly varying topography Lee, C.;Park, W.S.
  17. Coastal Eng. v.19 Extended refraction-diffraction equation for surface waves Massel, S.R.
  18. Proc. of 30th Japanese Conf. on Coastal Eng.(in Japanese) Wave field analysis by finite difference method Nishimura, H.;Maruyama, K.;Hirakuchi, H.
  19. J. of fluid Mech v.95 On the parabolic equation method for water-wave propagation Radder, A.C.
  20. Wave Motion v.7 Canonical equations for almost periodic, weakly nonlinear gravity waves Radder, A.C.;Dingemans, M.W.
  21. J. of Fluid Mech v.72 Scattering of surface waves by a conical island Smith, R.;Sprinks, T.
  22. Coastal Eng. v.32 Time-dependent equations for wave propagation on rapidly varying topography Suh, K.D.;Lee, C.;Park, W.S.