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Séminaire de Calcul Scientifique et Modélisation

[Séminaire CSM] The Shifted Boundary Method: a tool for high order immersed computations on unstructured grids.

Léo Nouveau

Salle 2

le 07 mars 2019 à 15:00

In this talk, some recent features on the immersed/embedded boundary method named Shifted Boundary Method (SBM) are presented. This new embedded approach intends to tackle some well known problems associated to immersed/embedded methods such as loss of accuracy and/or ill-conditioning of the associated algebraic system. After an introduction on immersed methods, we will discuss the basic formulation of the SBM, relying on two main ingredients: the combination of weak BC (Nitsche-type) and one sided extrapolation for high order accuracy. We will then discuss two recent developments. The first one consists in an improved formulation for elliptic PDEs exploring mixed finite element formulation. The availability of the solution derivatives as main unknowns is exploited to enrich the solution representation. Thus, while remaining in the context of a P1 finite element method, we obtain in the immersed case second order accuracy for both the solution and its derivatives, and a third order for the solution if only Dirichlet conditions are embedded. The second development shows the application of the SBM to free surface flows. In this case, the SBM is used to improve the embedding of the free surface interface.