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Ocean Dynamics

, Volume 60, Issue 4, pp 835–850 | Cite as

Idealised flow past an island in a dynamically adaptive finite element model

  • David R. MundayEmail author
  • David P. Marshall
  • Matthew D. Piggott
Article

Abstract

The problem of flow separation around islands is investigated using a dynamically adaptive finite element model to allow for resolution of the shear layers that form in the advent of separation. The changes in secondary circulation and vertical motion that occur in both attached and separated flows are documented, as is the degree of closure of the wake eddies. In the numerical experiments presented, the strongest motion always takes place at the sides of the idealised island, where flow curvature and shear act together to induce ascent. In contrast, it is the slower motion within the wake eddies that allow streamlines to extend from the bottom to the surface. We find no evidence for closure of the wake eddies. Rather, all of our separated experiments show that streamlines that pass through the eddies originate outside of the shear layers and frictional boundary layers on the upstream side of the idealised island. The numerical experiments demonstrate the potential for dynamically adaptive, unstructured meshes to resolve the separated shear layers that occur downstream of the idealised island, as well as the narrow boundary layers that form on the island itself.

Keywords

Dynamic adaptivity Finite elements Flow separation Island wakes Secondary circulations 

Notes

Acknowledgements

This work was funded by the UK Natural Environment Research Council under grant number NER/A/S/2003/00595/2. The comments of two anonymous reviewers led to significant improvement in the manuscript as a whole.

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Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • David R. Munday
    • 1
    Email author
  • David P. Marshall
    • 1
  • Matthew D. Piggott
    • 2
  1. 1.Atmospheric, Oceanic and Planetary Physics, Department of PhysicsUniversity of OxfordOxfordUK
  2. 2.Grantham Institute for Climate Change & Applied Modelling and Computation Group, Department of Earth Science and EngineeringImperial College LondonLondonUK

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