We describe a new algorithm for building piecewise linear approximations of an implicit surface. This algorithm is the first one guaranteeing that the implicit surface and its approximation are isotopic. Key-words: implicit surfaces, meshing, Morse theory INRIA † INRIA ‡ Rijksuniversiteit Groningen Maillage de surfaces implicites avec topologie certifiée Résumé : Nous décrivons un nouvel algori...

Observers are usually formulated as explicit systems of diierential equations and implemented using standard ODE solvers. In this paper, we show that there can be advantages in formulating the observer as a DAE (Diierential-Algebraic Equation). A canonical DAE observer is proposed and it is shown that it can be implemented using standard DAE solvers. The DAE implementation of the observer can b...

Here, we describe a numerical method which combines a mixed nite volume//nite element formulation on unstructured triangulations and a linearized implicit method for time advancing. A particular attention has been paid to the source term implicitation. This method is applied to three typical low-Reynolds number k ? " models, namely those of Lam-Bremhorst, Nagano-Tagawa and Speziale-Abid-Anderso...