Added-Mass-Partitioned Solvers: Robust and Accurate Computational Methods for Fluid Structure Interaction

From the design of aircraft and wind turbines to non-proliferation, technical and policy decisions are becoming increasingly reliant on computer simulation of complex multi-physics systems involving multiple interacting domains. In this talk I will discuss computational challenges associated with inter-domain coupling in the context of fluid-structure interaction (FSI). The discrete formulation of the fluid/solid interface conditions has a strong influence on the overall stability of the approach, and FSI solvers are historically found to su er when the so-called added-mass effects are large. These difficulties have their origin in the fact that the reaction of an immersed body to an applied force depends not only on the mass of the body but also on the mass of the fluid displaced by the body through its motion. Traditional approaches do not properly account for the fluid added mass, and can therefore experience a situation where the over-reaction of a light solid to an applied fluid force leads in turn to an even larger reaction from the fluid and so on. I will present recent work concerning the development and analysis of a new class of stable and accurate partitioned solvers that overcome added-mass instability through the use of so-called compatibility conditions. Schemes derived in this way are dubbed Added Mass Partitioned (AMP). Results will be presented for both compressible and incompressible flow regimes, and stability of the FSI coupling will be discussed using normal-mode stability theory.