Towards a Fluid-Structure Interaction Solver for Problems with Large Deformations Within the Open-Source SU2 Suite

Abstract

This paper describes a new framework for Fluid-Structure Interaction (FSI) modelling within the open-source code SU2. SU2 has been developed to solve complex, multi-physics problems described by Partial Differential Equations (PDEs), with an emphasis on problems involving aerodynamic shape optimization. Due to its modularity, the code provides an appropriate infrastructure for the solution of physical problems in several disciplines. This work provides SU2 with new tools that expand its capabilities in the fields of structural analysis and FSI. The focus will be on geometrically-nonlinear deformable solids in low-speed external flows. A Finite Element (FE) structural solver, able to deal with geometrical and material non-linearities in a static and a dynamic setting, has been built within the framework of SU2 alongside the existing solvers. Following the original object-oriented architecture in C++, a new structure compliant with the CFD solver has been developed. These new features will serve as a basis for future developments of FE-based strategies for the solution of PDEs. The structural solver has been coupled with the original fluid solver in SU2 using a partitioned approach. The structure of the code was fully recast to allow analysis across multiple zones and physical problems, currently limited to problems involving fluid and structural analysis. Both looselyand strongly-coupled strategies are available for the solution of the coupled FSI problem. Finally, the validity of the implementations is assessed by studying the behavior of a rigid square with a flexible cantilever at low Reynolds number. The results obtained demonstrate the capabilities of these new developments and further address the physics behind this benchmark problem.