An Introduction to Fluid-Structure Interaction: Application to the Piston Problem

Structure and fluid models need to be combined, or coupled, when problems of fluidstructure interaction (FSI) are addressed. We first present the basic knowledge required for building and then evaluating a simple coupling. The approach proposed is to consider a dedicated solver for each of the two physical systems involved. We illustrate this approach by examining the interaction between a gas contained in a one-dimensional chamber closed by a moving piston attached to an external and fixed point with a spring. A single model is introduced for the structure, while three models of increasing complexity are proposed for the fluid flow solver. The most complex fluid flow model leads us to the arbitrary Lagrangian Eulerian (ALE) approach. The pros and cons of each model are discussed. The computer implementations of the structure model, the fluid model, and the coupling use MATLAB scripts, downloadable from either http://www.utc.fr/∼elefra02/ifs or http://www.hds.utc.fr/∼boufflet/ifs.