Hostname: page-component-6bf8c574d5-rwnhh Total loading time: 0 Render date: 2025-02-15T10:23:50.906Z Has data issue: false hasContentIssue false
  • English
  • Français

Soliton generation by internal tidal beams impinging on a pycnocline: laboratory experiments

Published online by Cambridge University Press:  29 June 2012

Matthieu J. Mercier ,
Manikandan Mathur ,
Louis Gostiaux ,
Theo Gerkema ,
Jorge M. Magalhães ,
José C. B. Da Silva  and
Thierry Dauxois
Matthieu J. Mercier*
Affiliation:
Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA Laboratoire de Physique de l’École Normale Supérieure de Lyon, Université de Lyon, CNRS, 46 Allée d’Italie, F-69364 Lyon CEDEX 07, France
Manikandan Mathur
Affiliation:
Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA Laboratoire des Ecoulements Geophysiques et Industriels (LEGI), UMR 5519 CNRS-UJF-INPG, 21 rue des Martyrs, 38000 Grenoble, France Laboratoire de Météorologie Dynamique, École Polytechnique, 91128 Palaiseau, France
Louis Gostiaux
Affiliation:
Laboratoire des Ecoulements Geophysiques et Industriels (LEGI), UMR 5519 CNRS-UJF-INPG, 21 rue des Martyrs, 38000 Grenoble, France
Theo Gerkema*
Affiliation:
Royal Netherlands Institute for Sea Research (NIOZ), PO Box 59, 1790 AB Den Burg, Texel, The Netherlands
Jorge M. Magalhães
Affiliation:
CIMAR/CIIMAR, Centro Interdisciplinar de Investigacão Marinha e Ambiental and Departamento de Geociências, Ambiente e Ordenamento do Território, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
José C. B. Da Silva
Affiliation:
CIMAR/CIIMAR, Centro Interdisciplinar de Investigacão Marinha e Ambiental and Departamento de Geociências, Ambiente e Ordenamento do Território, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal
Thierry Dauxois
Affiliation:
Laboratoire de Physique de l’École Normale Supérieure de Lyon, Université de Lyon, CNRS, 46 Allée d’Italie, F-69364 Lyon CEDEX 07, France
*
†Email addresses for correspondence: mmercier@mit.edu, Theo.Gerkema@nioz.nl
†Email addresses for correspondence: mmercier@mit.edu, Theo.Gerkema@nioz.nl
Get access Rights & Permissions [Opens in a new window]

Abstract

In this paper, we present the first laboratory experiments that show the generation of internal solitary waves by the impingement of a quasi-two-dimensional internal wave beam on a pycnocline. These experiments were inspired by observations of internal solitary waves in the deep ocean from synthetic aperture radar (SAR) imagery, where this so-called mechanism of ‘local generation’ was argued to be at work, here in the form of internal tidal beams hitting the thermocline. Nonlinear processes involved here are found to be of two kinds. First, we observe the generation of a mean flow and higher harmonics at the location where the principal beam reflects from the surface and pycnocline; their characteristics are examined using particle image velocimetry (PIV) measurements. Second, we observe internal solitary waves that appear in the pycnocline, detected with ultrasonic probes; they are further characterized by a bulge in the frequency spectrum, distinct from the higher harmonics. Finally, the relevance of our results for understanding ocean observations is discussed.

JFM classification

Geophysical and Geological Flows: Internal waves Geophysical and Geological Flows: Ocean processes Waves/Free-surface Flows: Solitary waves
Type
Papers
Information
Journal of Fluid Mechanics , Volume 704 , 10 August 2012 , pp. 37 - 60
Copyright
Copyright © Cambridge University Press 2012

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Akylas, T. R., Grimshaw, R. H. J., Clarke, S. R. & Tabaei, A. 2007 Reflecting tidal wave beams and local generation of solitary waves in the ocean thermocline. J. Fluid Mech. 593, 297–313.CrossRefGoogle Scholar
2. Azevedo, A., Da Silva, J. C. B. & New, A. L. 2006 On the generation and propagation of internal solitary waves in the southern Bay of Biscay. Deep-Sea Res. I 53, 927–941.CrossRefGoogle Scholar
3. Da Silva, J. C. B., New, A. L. & Azevedo, A. 2007 On the role of SAR for observing ‘local generation’ of internal solitary waves off the Iberian Peninsula. Can. J. Remote Sensing 33 (5), 388–403.CrossRefGoogle Scholar
4. Da Silva, J. C. B., New, A. L. & Magalhaes, J. M. 2009 Internal solitary waves in the Mozambique Channel: observations and interpretation. J. Geophys. Res. 114, C05001.CrossRefGoogle Scholar
5. Da Silva, J. C. B., New, A. L. & Magalhaes, J. M. 2011 On the structure and propagation of internal solitary waves generated at the Mascarene Plateau in the Indian Ocean. Deep-Sea Res. I 58 (3), 229–240.CrossRefGoogle Scholar
6. Delisi, D. P. & Orlanski, I. 1975 On the role of density jumps in the reflexion and breaking of internal gravity beams. J. Fluid Mech. 69, 445–464.CrossRefGoogle Scholar
7. Fincham, A. & Delerce, G. 2000 Advanced optimization of correlation imaging velocimetry algorithms. Exp. Fluids 29, S1.CrossRefGoogle Scholar
8. Gerkema, T. 1996 A unified model for the generation and fission of internal tides in a rotating ocean. J. Mar. Res. 54 (3), 421–450.CrossRefGoogle Scholar
9. Gerkema, T. 2001 Internal and interfacial tides: beam scattering and local generation of solitary waves. J. Mar. Res. 59 (2), 227–255.CrossRefGoogle Scholar
10. Gostiaux, L. & Dauxois, T. 2007 Laboratory experiments on the generation of internal tidal beams over steep slopes. Phys. Fluids 19, 028102.CrossRefGoogle Scholar
11. Gostiaux, L., Didelle, H., Mercier, S. & Dauxois, T. 2007 A novel internal waves generator. Exp. Fluids 42, 123–130.CrossRefGoogle Scholar
12. Grisouard, N., Staquet, C. & Gerkema, T. 2011 Generation of internal solitary waves in a pycnocline by an internal wave beam: a numerical study. J. Fluid Mech. 676, 491–513.CrossRefGoogle Scholar
13. Horn, D. A., Imberger, J. & Ivey, G. N. 2001 The degeneration of large-scale interfacial gravity waves in lakes. J. Fluid Mech. 434, 181–207.CrossRefGoogle Scholar
14. Jackson, C. 2007 Internal wave detection using the moderate resolution imaging spectroradiometer (MODIS). J. Geophys. Res. 112, C11012.CrossRefGoogle Scholar
15. Jiang, C. H. & Marcus, P. S. 2009 Selection rules for the nonlinear interaction of internal gravity waves. Phys. Rev. Lett. 102, 124502.CrossRefGoogle ScholarPubMed
16. King, B., Zhang, H. P. & Swinney, H. L. 2009 Tidal flow over three-dimensional topography in a stratified fluid. Phys. Fluids 21, 116601.CrossRefGoogle Scholar
17. LeBlond, P. H. & Mysak, L. A. 1978 Waves in the Ocean. Elsevier.Google Scholar
18. Mathur, M. & Peacock, T. 2009 Internal wave beam propagation in non-uniform stratifications. J. Fluid Mech. 639, 133–152.CrossRefGoogle Scholar
19. Maugé, R. & Gerkema, T. 2008 Generation of weakly nonlinear nonhydrostatic internal tides over large topography: a multi-modal approach. Nonlinear Process. Geophys. 15, 233–244.CrossRefGoogle Scholar
20. Mercier, M. J., Martinand, D., Mathur, M., Gostiaux, L., Peacock, T. & Dauxois, T. 2010 New wave generation. J. Fluid Mech. 657, 308–334.CrossRefGoogle Scholar
21. Michallet, H. & Barthélemy, E. 1997 Ultrasonic probes and data processing to study interfacial solitary waves. Exp. Fluids 22, 380–386.CrossRefGoogle Scholar
22. New, A. L. & Da Silva, J. C. B. 2002 Remote-sensing evidence for the local generation of internal soliton packets in the central Bay of Biscay. Deep-Sea Res. 49 (5), 915–934.CrossRefGoogle Scholar
23. New, A. L. & Pingree, R. D. 1990 Large-amplitude internal soliton packets in the central Bay of Biscay. Deep-Sea Res. 37, 513–524.CrossRefGoogle Scholar
24. New, A. L. & Pingree, R. D. 1992 Local generation of internal soliton packets in the central Bay of Biscay. Deep-Sea Res. 39, 1521–1534.CrossRefGoogle Scholar
25. Tabaei, A. & Akylas, T. R. 2003 Nonlinear internal gravity wave beams. J. Fluid Mech. 482, 141–161.CrossRefGoogle Scholar
26. Tabaei, A., Akylas, T. R. & Lamb, K. G. 2005 Nonlinear effects in reflecting and colliding internal wave beams. J. Fluid Mech. 526, 217–243.CrossRefGoogle Scholar
27. Thomas, N. H. & Stevenson, T. N. 1972 A similarity solution for viscous internal waves. J. Fluid Mech. 54, 495–506.CrossRefGoogle Scholar
28. Thorpe, S. A. 1998 Nonlinear reflection of internal waves at a density discontinuity at the base of the mixed layer. J. Phys. Oceanogr. 28, 1853–1860.2.0.CO;2>CrossRefGoogle Scholar