FVM for FSI with large structural displacements

OpenFOAM [1], an Open Source object-oriented C++ library for numerical simulations in continuum mechanics implements the solvers by mimicking the governing equations in software. Ability to deal with complex fluid flow and structural analysis makes it a natural platform for Fluid-Structure Interaction (FSI) simulation in a single software. In this study, OpenFOAM is used to build a self-contained FSI solver, simulating the interaction between an incompressible Newtonian fluid and a St. Venant-Kirchhoff solid. Laminar fluid flow is modelled by the Navier-Stokes equa-tions in an Arbitrary Lagrangian-Eulerian (ALE) formulation while the large deformation of the solid is described by the geometrically nonlinear momentum equation in an updated Lagrangian formulation. Spatial discretisation of both models is performed using the second-order accurate un-structured Finite Volume Method (FVM), where the fluid model is discretised on the moving mesh [2] while the solid model is discretised on the fixed mesh, updating its configuration in accordance with the displacement from the previous time step. Automatic mesh motion solver [3] is used to accommodate the fluid-solid interface deformation. Temporal discretisation for the fluid model is performed using a fully implicit second-order accurate three-time-levels difference scheme, while the second-order temporal discretisation for the solid is accomplished by the composite schem