Seminario del 2025
Ottobre
24
2025
Marco Feder
Seminario di analisi numerica
The fictitious domain approach is a powerful technique for solving partial differential equations
posed on complicated and possibly moving domains by embedding the physical domain of
interest into a simpler computational domain.
We present a family of augmented Lagrangian-based preconditioners for efficiently solving
multiple saddle-point linear systems arising from the finite element discretization of fictitious
domain formulations. We provide a detailed spectral analysis of the proposed preconditioners,
deriving lower and upper bounds for the eigenvalues of the preconditioned system, and showing
their independence with respect to discretization parameters when ideal versions of the preconditioners are employed. The robustness and efficiency of the preconditioners, when used in
combination with flexible GMRES, are validated through extensive numerical experiments in
both two and three dimensions and with different geometries. Cheaper and modified variants of
these preconditioners are also considered, in order to reduce the application cost.
In addition, we extend our approach to the more challenging case of fluid-structure interaction
(FSI) problems, demonstrating that the present methodology remains robust and can
effectively handle such complex scenarios. The relevant computational aspects related to the
memory distributed implementation (based on the C++ finite element library DEAL.II) of these
methodologies will be discussed.