Characteristics of Ocean Wave Radiation Patterns in a Dense Layer of Fluid

밀도층 유체에서 해양 방사파 패턴 특징

  • Min, Eun-Hong (Department of Naval Architecture and Ocean Engineering, Inha University) ;
  • Choi, Ha-Yun (Department of Naval Architecture and Ocean Engineering, Inha University) ;
  • Kim, Young-Gyu (Agency for Defense Development) ;
  • Paik, Kwang-Jun (Department of Naval Architecture and Ocean Engineering, Inha University) ;
  • Koo, Weon-Cheol (Department of Naval Architecture and Ocean Engineering, Inha University)
  • 민은홍 (인하대학교 조선해양공학과) ;
  • 최하윤 (인하대학교 조선해양공학과) ;
  • 김영규 (국방과학연구소) ;
  • 백광준 (인하대학교 조선해양공학과) ;
  • 구원철 (인하대학교 조선해양공학과)
  • Received : 2018.10.08
  • Accepted : 2019.02.22
  • Published : 2019.02.28


The sea is stratified with water that has different densities because of pressure, temperature, and salinity. When conducting studies of internal waves in the ocean, the fluid is assumed to have layers that have discrete densities. This assumption is made because it is difficult to achieve layers that exhibit gradual changes in the density of the water. In this study, we used previous studies on ocean waves and their radiation issues in the density layer fluid to investigate the characteristics of internal waves in the ocean and their radiation patterns induced by a moving body in a stratified fluid. We also studied the difference in wave radiation between the density gradient layer and the discrete density layer. We found that the wave radiation patterns depended on the velocity of the moving body and the change in the density of the water. The crest apex shift phenomenon was observed in the density gradient in the layer of fluid.


Brunt-$V{\ddot{a}}is{\ddot{a}}l{\ddot{a}}$ frequency;Internal wave;Stratification;Density gradient layer;Discrete density layer


Supported by : 국방과학연구소, 한국연구재단


  1. Alpers, W., La Violette, P.E., 1993. Tide-generated Nonlinear Internal Wave Packets in the Strait of Gibraltar Observed by the Synthetic Aperture Radar Aboard the ERS-1 Satellite. Proceedings of the First ERS-1 Symposium - Space at the Service of our Environment Published by ESA, Paris, France, ESA Sp-359, 753-758.
  2. Gerkema, T., Zimmerman, J.T.F., 2008. An Introduction to Internal Waves. Lecture Notes, NIOZ Royal Netherlands Institute for Sea Research, Den Burg.
  3. Keller, J.B., Munk, W.H., 1970. Internal Wave Wakes of a Body Moving in a Stratified Fluid. Physics of Fluids, 13(6), 1425-1431.
  4. Kundu, P.K., Cohen, I.M., Dowling, D.R., 2016. Fluid Mechanics, 6th edition, Academic Press, Cambridge.
  5. Min, E.H., Koo, W.C., 2017. Hydrodynamic Characteristics of Internal Waves Induced by a Heaving Body in a Two-layer Fluid. Ocean Engineering, 145, 290-303.
  6. Robey, H.F., 1997. The Generation of Internal Waves by a Towed Sphere and its Wake in a Thermocline. Physics of Fluids, 9(11), 3553-3367.
  7. Sharman, R.D., Wurtele, M.G., 1983. Ship Waves and Lee Waves. Journal of Atmospheric Sciences, 40, 396-427.<0396:SWALW>2.0.CO;2<0396:SWALW>2.0.CO;2
  8. Ten, L., Kashiwagi, M., 2004. Hydrodynamics of a Body Floating in a Two-layer Fluid of Finite Depth - Part 1 Radiation Problem. Journal of Marine Science and Technology, 9(3), 127-141.
  9. Tunaley, J.K.E., 2012. The Theory of Internal Wave Wakes. London Research and Development Corporation Final Report CR 2012-119, Defence Research and Development, Ottawa, Canada.
  10. Tunaley, J.K.E., 2015. Ship Wakes Generated in a Diffuse Internal Layer. London Research and Development Corporation Report CR 2015-C093, Defence Research and Development, Ottawa, Canada.
  11. Turner, J.S., 1973. Buoyancy Effects in Fluids. Cambridge University Press, Cambridge.
  12. Yeung, R.W., Nguyen, T.C., 1999a. Radiation and Diffraction of Waves in a Two-layer Fluid. Proceedings of the 22nd Symposium of Naval Hydrodynamics, Washington, 875-891.
  13. Yeung, R.W., Nguyen, T.C., 1999b. Waves Generated by a Moving Source in a Two-layer Ocean of Finite Depth. Journal of Engineering Mathematics, 35(1-2), 85-107.
  14. Liu, A.K., Chang, Y.S., Hsu, M.K., Liang, N.K., 1998. Evolution of Nonlinear Internal Waves in the East and South China Seas. Journal of Geophysical Research, 103(C4), 7995-8008.