Simulation of fluid-structure interactions Co-simulations applied to hydrodynamics

Fluid-Structure Interaction (FSI) refers to the exchange of energy between the movements of a structure and the flow of a fluid. It is encountered in naval hydrodynamics in a wide range of situations – and concerns many other industrial sectors (aeronautical and automotive construction, civil and nuclear engineering). In particular, it determines the hydrodynamic performance of many of the systems used to propel and stabilize ships (propellers, rudders, hulls, sails).

Current numerical simulation techniques offer the possibility of modeling fluid-structure interaction in real geometric configurations. So-called "co-simulation" strategies use two calculation codes: a structural mechanics code and a fluid mechanics code. They take advantage of the functionalities of both simulation tools, and enable fluid-structure interactions to be represented in fine detail.

Developed over several decades, these calculation techniques are available to industrial engineers to study situations requiring the rendering of IFS. They are available both in general-purpose commercial simulation tools and in open-source codes.

This article provides an introduction to these computational techniques, with examples of their application to naval hydrodynamics. It is aimed primarily at students of mechanical engineering, and more generally at scientific computing engineers and designers of installations concerned by this issue, in the naval or marine renewable energy industries.

After providing some background on IFS, the article reviews the modeling and formulation of fluid and structural dynamics problems, as well as the methods available to engineers in computational codes. Coupling strategies in time and space are then outlined –, highlighting the particular points of coupling (numerical stability and accuracy in particular). Three examples of applications to naval hydrodynamics are then presented.

The subject is complementary to numerous presentations on IFS and numerical simulation in fluid and structural mechanics. These are the subject of specific dossiers accessible in the Techniques de l'Ingénieur document database. Readers will find these references in the documentation section associated with this article. An additional bibliography and links to websites provide useful resources for furthering your knowledge of the subject.

At the end of the article, you'll find a glossary of important terms and expressions.