DOI QR코드

DOI QR Code

A Study of the Appearance Characteristics and Generation Mechanism of Giant Waves

대양에서의 거대파랑 출현 특성과 발생 기구에 관한 연구

  • Shin Seung-Ho (Ocean Engineering Research Department, Maritime & Ocean Engineering Research Institute) ;
  • Hong Key-Yong (Ocean Engineering Research Department, Maritime & Ocean Engineering Research Institute)
  • 신승호 (한국해양연구원 해양시스템안전연구소 해양시스템기술연구본부) ;
  • 홍기용 (한국해양연구원 해양시스템안전연구소 해양시스템기술연구본부)
  • Published : 2006.04.01

Abstract

In the wave spectrum distribution based on linear wave theory, the appearance of a giant wave whose wave height reaches to 30m has been considered next to almost impossible in a real sea However since more than 10 giant waves were observed in a recent investigation of global wave distribution which was carried out by the analysis of SAR imagines for three weeks, the existence of the giant waves is being recognized and it is considered the cause of many unknown marine disasters. The change of wave height distribution concerning a formation of wave train, nonlinear wave to wave interaction and so on were raised as the causes of the appearance of the giant waves, but the occurrence mechanism of the giant waves hasn't been cleared yet. In present study, we investigated appearance circumstances of the giant waves in real sea and its occurrence mechanism was analyzed based on linear and nonlinear wave focusing theories. Also, through a development of numerical model of the nonlinear $schr\"{o}dinger$ equation, the formations of the giant wave from progressive wave train were reproduced.

선형파 이론에 의한 파랑스펙트럼 분포에 의해서는 30m 크기의 파랑은 현실적으로 거의 발생 불가능하다고 인식되어 왔다. 그러나 최근의 위성 영상을 이용한 조사에 의해 3주간의 기간 동안 25m 이상의 거대파가 10개 이상 관측됨에 따라 실해역에서 빈번히 마주칠 수 있는 현상임이 입증되었으며 이에 따라 지금까지 원인 불명으로 치부되어 왔던 많은 해양 재난이 거대파에 의해 발생했던 것으로 추정되고 있다. 거대파의 발생 원인으로는 파군 형성과 관련한 파고분포 특성의 변화, 전파하는 파군의 비선형 공명간섭 등이 제기되고 있으나, 그 출현의 복잡성과 자료의 부족 등으로 아직 명확하게 해명되지 못하고 있다. 본 연구에서는 실해역에서 발생하는 거대파의 실태 및 선형 및 비선형 파랑집중 이론에 근거한 거대파 발생 기구를 고찰하였으며, 비선형 파랑전파를 모사할 수 있는 수치모형을 개발하여 비선형 파랑 집중에 의한 거대 파랑의 형성을 모사하였다.

References

  1. Benjamin, T. B. and Feir, J. E. (1967), 'The disintegration of wave trains on the deep water', J. Fluid Mech, Vol. 27, pp. 417-430 https://doi.org/10.1017/S002211206700045X
  2. Bigio (1995), 'Luis and the Buoys and the Queen', 4th Int. Workshop on Wave Hindcasting and Forecasting
  3. Haver, S. (2000), 'Evidences of the Existence of Freak Waves', Rogue waves 2000, pp. 129-140
  4. Kharif, C. and Pelinovsky, E. (2003), 'Physical mechanisms of the rogue wave phenomenon', European J. of Mechanics B/Fluids, Vol. 22, pp. 603-634 https://doi.org/10.1016/j.euromechflu.2003.09.002
  5. Lehner S., Gunther, H. and Rosenthal, W. (2005), 'Extreme Wave Obsevations from Radar Data Set', Ocean Waves Measurement and Analysis, 5th Int. Symp. Waves 2005, pp. 69_1-69_10
  6. Liu, P. C. and Pinho, U. F. (2004), 'Freak waves more frequent than rare !', Annales Geophysicae, Vol. 22, pp. 1839-1842 https://doi.org/10.5194/angeo-22-1839-2004
  7. Mei, C. C., Stiassnie, M. and Yue, D. K.-P. (2005), 'Theory and Applications of Ocean Surface Waves, Part 2: Nonlinear Aspects', Advanced Series on Ocean Engineering, Vol. 23, World Scientific Press
  8. Hong, K. and Shin, S. H. (2005), 'Distribution of Impact Pressures on the Surface of Inclined Cylinder casued by Laboratory Breaking Waves', Ocean Waves Measurement and Analysis, 5th Int. Symp. Waves 2005, pp. 130_1-130_9
  9. White, B. and Fornberg, B. (1998), 'On the chance of freak waves at sea', J. Fluid Mech., Vol. 355, pp. 113-138 https://doi.org/10.1017/S0022112097007751
  10. Whitham, G. B. (1974), 'Linear and Nonlinear Waves', Wiley Press
  11. Zhou, D., Chan, E. S., and Melville, W. K. (1991). 'Wave impact pressures on vertical cylinders'. Appl. Ocean Res., Vol. 13(5), pp. 220-234 https://doi.org/10.1016/S0141-1187(05)80046-X