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Ocean Dynamics

, Volume 62, Issue 5, pp 683–700 | Cite as

Complex geophysical wake flows

Madeira Archipelago case study
  • Rui Miguel A. Caldeira
  • Pablo Sangrà
Article

Abstract

Idealized studies of island wakes often use a cylinder-like island to generate the wake, whereas most realistic studies use a close representation of the oceanic bathymetry immersed in a complex representation of the “ambient” geophysical flows. Here, a system of multiple islands was placed into numerical and experimental channels, in order to focus on the complexity of the archipelago wake, including (a) the influence of small neighboring islands and (b) the role of the island-shelf. The numerical geostrophic and stratified channel was built using a three-dimensional primitive equation model, considering a realistic representation of the Madeira archipelago bathymetry, with prescribed initial and boundary conditions. Results from the simulations show that the neighboring islands alter the near-field wake. Small eddies generated by the neighboring islands lead to destabilization of the shear layers of the larger island. Laboratory experiments carried out in the Coriolis rotating tank corroborated this near-field disruptive mechanism. The neighboring island perturbation effect was present whatever the direction of the incoming flow, but under different regimes. North–south wakes produced geostrophic eddies (≥ R d), whereas west–east wakes produced (exclusively) ageostrophic submesoscale eddies (< < R d) which traveled offshore with wave-like motion. The archipelago shelf contributed to the asymmetric vertical migration of oceanic vorticity. Cyclonic vorticity dominated the surface dynamics, whereas anticyclonic circulation prevailed at the bottom part of the linearly stratified upper layer. This study identifies several likely wake scenarios induced by the Madeira archipelago, and may serve as guide for future multiscale numerical studies and in situ campaigns.

Keywords

Island wake Submesoscale eddies Boundary layer disruption Hydrodynamic drafting Topographic trapped waves Vertical shear Subinertial instabilities 

Notes

Acknowledgements

The authors are grateful for research funding from FCT-Portuguese National Science Foundation. This work was initiated as part of an FCT post-doctoral grant (SFRH/BPD/14871/2003) and continued in the scope of two subsequent research funding initiatives (POCI/MAR/57265/2004; PPCDT/MAR/57265/2004). We would like to thank the contributions of Changming Dong (Charles) and Dmitri Boutov for providing some of the scripts that were used for the pre- and post-processing of the ROMS solutions. We would also like to thank Stefan Rhia and Euclides Luis for their interest in the topic; regrettably, their contribution was not eligible to be included in the current work. Discussions with Alexandre Stegner and Olivier Cadot, during Rui Caldeira’s visit to the École Nationale Supérieure de Techniques Avancées (ENSTA), Paris, are reflected in the content of this report. Comments from David Dietrich and from an anonymous reviewer substantially contributed to the improvement of the first versions of this manuscript.

Supplementary material

10236_2012_528_MOESM1_ESM.mp4 (2.7 mb)
(mp4 2.73 MB)

References

  1. Alben S (2009) Wake-mediated synchronization and drafting in coupled flags. J Fluid Mech 641:489–496CrossRefGoogle Scholar
  2. Antonia R, Mi J (1998) Approach towards self-preservation of turbulent cylinder and screen wakes. Exp Therm Fluid Sci 17:277–284CrossRefGoogle Scholar
  3. Aristegui J, Sangra P, Hernandez-Leon S, Canton M, Hernandez-Guerra A, Kerling JL (1994) Island-induced eddies in the canary islands. Deep-Sea Res 41(10):1509–1525CrossRefGoogle Scholar
  4. Aristegui J, Tett P, Hernandez-Guerra A, Basterretxea G, Montero MF, Wild K, Sangra P, Hernandez-Leon S, Canton M, GarciaBraun JA, Pacheco M, Barton ED (1997) The influence of island-generated eddies on chlorophyll distribution: a study of mesoscale variation around gran canaria. Deep-Sea Res Part 1 Oceanogr Res Pap 44(1):71CrossRefGoogle Scholar
  5. Barton ED, Basterretxea G, Flament P, Mitchelson-Jacob EG, Jones B, Aristegui J, Herrera F (2000) Lee region of gran canaria. J Geophys Res 105:17173–17193CrossRefGoogle Scholar
  6. Beckmann A, Haidvogel D (1993) Numerical simulation of flow around a tall isolated seamount. part i: problem formulation and model accuracy. J Phys Oceanogr 23:1736–1753CrossRefGoogle Scholar
  7. Boyer DL, Davies PA (2000) Laboratory studies of orographic effects in roating and stratified flows. Annu Rev Fluid Mech 32:165–202CrossRefGoogle Scholar
  8. Caldeira RMA, Groom S, Miller P, Pilgrim D, Nezlin N (2002) Sea-surface signatures of the island mass effect phenomena around madeira island, northeast atlantic. Remote Sens Environ 80:336–360CrossRefGoogle Scholar
  9. Caldeira RMA, Marchesiello P, Nezlin NP, DiGiacomo PM, McWilliams JC (2005) Island wakes in the Southern California Bight. J Geophys Res 110:C11012CrossRefGoogle Scholar
  10. Calil PH, Richards KJ, Jia Y, Bidigare RR (2008) Eddy activity in the lee of the hawaiian islands. Deep-Sea Res Part 2 Top Stud Oceanogr 55(10–13):1179–1194. doi: 10.1016/j.dsr2.2008.01.008 CrossRefGoogle Scholar
  11. Chavanne C, Flament P, GurgelGurgel KW (2010) Interactions between a submesoscale anticyclonic vortex and a front. J Phys Oceanogr 40:1802–1818CrossRefGoogle Scholar
  12. Coutis PF, Middleton JH (2002) The physical and biological impact of a small island wake in the deep ocean. Deep-Sea Res Part 1 Oceanogr Res Pap 49(8):1341–1361CrossRefGoogle Scholar
  13. Dalton C, Xu Y, Owen JC (2001) The suppression of lift on a circular cylinder due to vortex shedding at moderate Reynolds numbers. J Fluids Struct 15:617–628CrossRefGoogle Scholar
  14. Dietrich DE, Bowman MJ, Lin CA, Mestas-Nunez A (1996) Numerical studies of small island wakes in the ocean. Geophys Astrophys Fluid Dyn 83:195–231CrossRefGoogle Scholar
  15. Dong CM, McWilliams JC (2007) A numerical study of island wakes in the Southern California Bight. Cont Shelf Res 27(9):1233–1248CrossRefGoogle Scholar
  16. Dong CM, McWilliams JC, Shchepetkin AF (2007) Island wakes in deep water. J Phys Oceanogr 37(4):962–981CrossRefGoogle Scholar
  17. Estrade P, Middleton JH (2010) A numerical study of island wake generated by an elliptical tidal flow. Cont Shelf Res 30:1120–1135CrossRefGoogle Scholar
  18. Furukawa K, Wolanski E (1998) Shallow-water frictional effects in island wakes. Estuar Coast Shelf Sci 46:599–608CrossRefGoogle Scholar
  19. Heywood KJ, Stevens DP, Bigg GR (1996) Eddy formation behind the tropical island of aldabra. Deep-Sea Res Part 1 Oceanogr Res Pap 43(4):555CrossRefGoogle Scholar
  20. Holton J (1992) An introduction to dynamic meteorology. Academic, New YorkGoogle Scholar
  21. Huang Z, Ferre J, Kawall J, Keffer J (1995) The connection between near and far regions of the turbulent porous body wake. Exp Therm Fluid Sci 11:143–154CrossRefGoogle Scholar
  22. Kersale M, Doglioli AM, Petrenko A (2011) Sensitivity study of the generation of mesoscale eddies in a numerical model of Hawaii islands. Ocean Sci 7:277–291CrossRefGoogle Scholar
  23. Kuo CH, Chiou LC, Chen CC (2007) Wake flow pattern modified by small control cylinders at low Reynolds number. J Fluids Struct 23:938–956CrossRefGoogle Scholar
  24. Large W, Mcwilliams JC, Doney S (1994) Oceanic vertical mixing—a review and a model with no local boundary layer parameterization. Rev Geophys 32(4):363–403CrossRefGoogle Scholar
  25. Mori M, Griffiths MESRW (1987) Coherent baroclinic eddies on a sloping bottom. J Fluid Mech 183(45–62):45–62CrossRefGoogle Scholar
  26. Parezanovića V, Cadot O (2009) The impact of a local perturbation on global properties of a turbulent wake. Phys Fluids 21(071701):071701CrossRefGoogle Scholar
  27. Perret G, Stegner A, Dubos T, Chomaz JM, Farge M (2006) Stability of parallel wake flows in quasigeostrophic and frontal regimes. Phys Fluids 18(12)Google Scholar
  28. Poulin FJ, Swaters GE (1999) Sub-inertial dynamics of density-driven flows in a continuously stratified fluid on a sloing bottom. II. Isolated eddies and radiating cold domes. Proc R Soc Lond 455:2305–2329CrossRefGoogle Scholar
  29. Protas B (2008) Vortex dynamics models in flow control problems. Nonlinearity 21(9):R203CrossRefGoogle Scholar
  30. Ristroph L, Zhang J (2008) Anomalous hydrodynamic drafting of interacting flapping flags. Phys Rev Lett 101(194502):1–4Google Scholar
  31. Sakamoto H, Tan K, Haniu H (1991) An optimum suppression of fluid forces by controlling a shear layer separated from a square prism. J Fluids Eng 113:183–189CrossRefGoogle Scholar
  32. Sangra P, Pelegri JL, Hernandez-Guerra A, Arregui I, Martin JM, Marrero-Diaz A, Martinez A, Ratsimandresy AW, Rodriguez-Santana A (2005) Life history of an anticyclonic eddy. J Geophys Res 110:C03021CrossRefGoogle Scholar
  33. Sangra P, Auladell M, Marrero-Diaz A, Pelegri JL, Fraile-Nuez E, Rodriguez-Santana A, Martin JM, Mason E, Hernandez-Guerra A (2007) On the nature of oceanic eddies shed by the island of gran canaria. Deep-Sea Res Part 1 Oceanogr Res Pap 54(5):687–709CrossRefGoogle Scholar
  34. Shchepetkin AF, McWilliams JC (1998) Quasi-monotone advection schemes based on explicit locally adaptive dissipation. Mon Weather Rev 126:1541–1580CrossRefGoogle Scholar
  35. Shchepetkin AF, McWilliams JC (2003) A method for computing horizontal pressure-gradient force in an oceanic model with a nonaligned vertical coordinate. J Geophys Res-Oceans 108:3090CrossRefGoogle Scholar
  36. Shchepetkin AF, McWilliams JC (2005) The regional oceanic modeling system (roms): a split-explicit, free-surface, topography-following-coordinate oceanic model. Ocean Model 9(4):347–404CrossRefGoogle Scholar
  37. Siedler G, Zenk W, Emery WJ (1985) Strong current events related to a subtropical front in the northeast atlantic. J Phys Oceanogr 15:885–896CrossRefGoogle Scholar
  38. Strykowski PJ, Sreenivasan K (1990) On the formation and suppression of vortex shedding at low Reynolds numbers. J Fluid Mech 218:71–107CrossRefGoogle Scholar
  39. Sutyrin GG, Grimshaw R (2010) The long-time interaction of an eddy with shelf topography. Ocean Model 32:25–35CrossRefGoogle Scholar
  40. Teinturier S, Stegner A, Didelle H, Viboud S (2010) Small-scale instabilities of an island wake flow in a rotating shallow-water layer. Dyn Atmos Ocean 49:1–24CrossRefGoogle Scholar
  41. Tomczak M (1988) Island wakes in deep and shallow-water. J Geophys Res-Oceans 93:5153–5154CrossRefGoogle Scholar
  42. White L, Wolanski E (2008) Flow separation and vertical motions in a tidal flow interacting with a shallow-water island. Estuar Coast Shelf Sci 77(3):457–466CrossRefGoogle Scholar
  43. Wolanski E, Imberger J, Heron M (1984) Island wakes in shallow coastal waters. J Geophys Res-Oceans 89:553–569CrossRefGoogle Scholar
  44. Wolanski E, Asaeda T, Tanaka A, Deleersnijder E (1996) Three-dimensional island wakes in the field, laboratory experiments and numerical models. Cont Shelf Res 16:1437–1452CrossRefGoogle Scholar
  45. Zhang J, Childress S, Libchaber A, Shelley M (2000) Flexible filaments in a flowing soap film as a model for one-dimensional flags in a two-dimensional wind. Nature 408:835–839CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  1. 1.CIIMAR—Interdisciplinary Centre of Marine and Environmental ResearchPortoPortugal
  2. 2.CCM—Center for Mathematical SciencesUniversidade da MadeiraFunchalPortugal
  3. 3.Departamento de Fisica, Edificio de Ciencias BasicasUniversidad de Las Palmas de Gran CanariaLas PalmasSpain

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