Fluid-Structure Interaction Using an Arbitrary Lagrangian-Eulerian Fluid Solver Coupled to a Positional Lagrangian Shell Solver

Abstract

This work consists of the development of a partitioned 3D computational code for non linear geometrical fluid-structure interaction analysis using the Finite Element Method. The fluid solver is explicit and its time integration is based on characteristics, which introduces automatically stabilizing terms on stream direction. The Navier-Stokes equations are written in the arbitrary Lagrangian-Eulerian (ALE) description, in order to accept moving boundaries and coupling with Lagrangian shell elements.
The structure is modeled using a positional FEM formulation to deal with geometrical nonlinear dynamics
of shells using a methodology based on the minimum potential energy theorem written regarding nodal positions and generalized unconstrained vectors, not displacements and rotations. These characteristics
avoid the use of large rotation approximations.The coupling between the two different meshes is done by mapping the fluid boundary nodes local positions over the shell elements and vice versa, avoiding the need of matching fluid and shell nodes. The fluid mesh is adapted using one simple approach based shell positions and velocities. The efficiency and robustness of the proposed approach is demonstrated by examples.