Three Dimensional FSI Simulation of Extruded Rod Bundles Immersed in Fluid Using Partitioned Coupling Technique

<jats:p>Dynamic response of extruded rod bundles immersed in fluid is an important feature as a seismic response of fuel rods. For their safety assessment, prediction of dynamic behavior is required. For the prediction, fluid structure interaction should be considered properly which significantly affects the dynamic behavior. However, actual behavior of the bundles includes complex modes of response and not only the interaction between fluid and structure but also the interaction between the bundles and external structure can affect its behavior. Therefore simulation method which can consider the interaction of complicated structures is expected. There are two different approaches for simulating their dynamic behavior. One is the monolithic method, in which one matrix constructed from two physics is solved, and the other is the partitioned method in which two different matrices are solved separately. The partitioned method enables us to utilize an advantage of existing simulation codes, for example their high parallel efficiency. One of the present authors developed a numerical simulation system ADVENTURE, which is a general purpose finite element simulation system which includes several finite element solvers designed to suite for large scale application in parallel computing environments. The authors have developed a simulation system of fluid structure interaction based on ADVENTURE system applying partitioned coupling technique. In this paper, the overview of the system is explained and several numerical simulation results of the dynamic response of the extruded rod bundles are shown. The result shows this coupling technique can give reasonable results and it can apply a larger scale problem of 9×9 arrays of extruded rod bundles.</jats:p>