Fluid-Structure Interaction: Numerical Validation of an Homogenization Method

The considered structure is a nuclear reactor vessel, composed of two concentric inner and outer structures, with water in the annular space between. Previous dynamic analysis showed that this water lead to strong fluid structure interaction coupling the structures. The annular space is filled by regularly spaced cylinders, which are linked to the inner structure. Their influence was neglected in the first studies. Recent analyses, using homogenization methods, show that these cylinders increase the FSI coupling in the vessel. The homogenization methods is based on general principles developed in the study of tube bundles, and very well established, from a physical and numerical point of view. Even if it seems reasonable to have a high degree of confidence in the results obtained with this homogenization methods, it is still interesting to validate the results of the “homogenization analysis” with a comparison with “direct calculations”, taking into account the real geometry of the system. The paper presents the main results of the validation. The main limitation of the “direct calculations” is the size of the mesh and the computer time. The main limitation for the “homogenization analysis” is that the actual modeling does not take into account the anisotropy in the Fluid Structure Interaction in the annular space.