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The numerical simulation of multiscale and multiphysics problems requires efficient tools for spatial localization and model reduction. A general strategy combining Domain Decomposition and Nonuniform Transformation Field Analysis (NTFA) is proposed herein for the simulation of nuclear fuel assemblies at the scale of a full nuclear reactor. The model at subdomain level solves the full elastic problem but with a reduced nonlinear loading, based on simplified boundary conditions, reduced creep flow rules, projected sign preserving contact conditions, and a NTFA like reduced friction law to get the evolution of each slipping mode. With this loading reduction, the local solution can be explicitly obtained from a small set of precomputed elementary elastic solutions. The numerical tests indicate that considerable cost reduction (a factor of 50 to 1000) can be achieved while preserving engineering accuracy. [ABSTRACT FROM AUTHOR]

Dynamic Mode Decomposition (DMD) is a recent post-processing technique that extracts from snapshots dynamic relevant information for the flow. Without explicit knowledge of the dynamical operator, the DMD algorithm determines eigenvalues and eigenvectors of an approximate linear model. The ability of DMD to extract dynamically relevant features of the flow predispose it for building a representative reduced-order subspace from the data and for deriving a reduced-order model. The use of the DMD for reduced-order modelling will be investigated in this paper on experimental flow data of a cylinder wake. [ABSTRACT FROM AUTHOR]