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Sébastien Blaise's PhD Thesis
Development of a Finite Element marine model
by Sébastien Blaise (Public defense : November 6th, 2009, 16h00, BARB94)
Numerical models are very helpful to understand the behaviour of the marine system. Ocean models have been developed for more than forty years, and their design is an area of active research. If the representation of the physics has been highly improved, the fundamental numerical technique has not evolved: they still use the finite difference method on structured grids. Recent efforts focus on developing the new generation of ocean models, taking advantage of the potential of modern numerical methods. Based on unstructured grids, such model allow to faithfully represent complex topographic features such as the coastlines, narrow straits and islands. The mesh resolution can be refined locally in regions of interest or where the dynamics is more demanding.
This PhD dissertation focuses on the development of a three-dimensional baroclinic marine model using the Discontinuous Galerkin Finite Element method. The model is described, with some results of baroclinic simulation. The rest of the thesis is devoted to different types of unresolved physics. Two different boundary layers are introduced: the bottom velocity boundary layer and the boundary layer of the residence time. Both parameterisation and representation using the extended finite element method are discussed. A chapter is dedicated to the treatment of the horizontal density gradient in baroclinic column models. Attention is paid to the stability of the method under different configurations. Then, the turbulence modelling in three-dimensional models is studied by comparing the effect of different turbulence closure models on a simulation of the flow around a shallow-water island.
Pdf-file of thesis (local server)
Jury : |
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