This study is based on the simulation of the fluid-structure interaction on risers. We aim to quantify the structural response of these long flexible pipes, used for the extraction of offshore petroleum when they are subjected to marine currents. Toe occurring phenomenon is known as VIV (Vortex induced VIbration). These problems are a relevant challenge for several offshore companies, which are associated with K-Epsilon in a Citeph project. Toe project's goal is to use the FSI simulation tool developed by K-Epsilon and initially used for the simulation offlexible membranes such as sails, to model these VIV phenomena.

Toe problem of VIV in the case of a riser is a strongly coupled problem, meaning that the added mass is not negligible compared to the mass of the structure. This can be challenging for most fluid-structure interaction software. A strongly coupled algorithm is presented [6].

First, numerical results of fluid around cylinders are presented and compared to experimental results ([l], [10]) with several turbulence models, and time step sizes. Toen, Chaplin's benchmark is presented with experimental / numerical comparison [3].