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| Titel |
Discretizing the Gent-McWilliams velocity and isopycnal diffusion with a discontinuous Galerkin finite element method |
| VerfasserIn |
A. Pestiaux, T. Kärnä, S. Melchior, J. Lambrechts, J. F. Remacle, E. Deleersnijder, T. Fichefet |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250059440
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| Zusammenfassung |
| The discretization of the Gent-McWilliams velocity and isopycnal diffusion with a
discontinuous Galerkin finite element method is presented. Both processes are implemented
in an ocean model thanks to a tensor related to the mesoscale eddies. The antisymmetric part
of this tensor is computed from the Gent-McWilliams velocity and is subsequently
included in the tracer advection equation. This velocity can be constructed to be
divergence-free. The symmetric part that describes the diapycnal and isopycnal diffusions
requires a special treatment. A stable and physically sound isopycnal tracer diffusion
scheme is needed. Here, an interior penalty method is chosen that enables to build
stable diffusion terms. However, due to the strong anisotropy of the diffusion, the
common-usual penalty factor by Ern et al. (2008) is not sufficient. A novel method
for computing the penalty term of Ern is then proposed for diffusion equations
when both the diffusivity and the mesh are strongly anisotropic. Two test cases are
resorted to validate the methodology and two more realistic applications illustrate
the diapycnal and isopycnal diffusions, as well as the Gent-McWilliams velocity. |
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