Francesca Renzi: Solving FSI with large added mass through loosely-coupled fitted and unfitted methods

Speaker
Francesca Renzi, Politecnico di Milano

Abstract
Solving fluid-structure interaction (FSI) problems when the fluid and structure densities are similar (large added mass), such as in hemodynamics, is challenging since the stability of the adopted numerical scheme could be compromised. Moreover, suitable methods are needed to handle systems characterized by rapid dynamics and huge deformations, such as the immersed cardiac valves.
In this talk, we first present a new loosely-coupled scheme based on Dirichlet and Neumann interface conditions suited for hemodynamics. Stability analysis on a benchmark problem proves that the proposed LC scheme is conditionally stable in large added mass regimes, under a constraint on a parameter α.
Numerical experiments in hemodynamic settings confirm the theoretical results, demonstrating the effectiveness and applicability of the proposed schemes.
Secondly, we address the case of realistic scenarios arising in the context of ventricular hemodynamics, where blood interacts with immersed valves, thereby calling for non-conforming meshes.
To this aim, we present the Resistive Immersed Implicit Surface method coupled with a turbulent fluid and we show several results for healthy and pathological scenarios in the right heart, coming from a collaboration with Ospedale Borgo Trento in Verona.