A zonal Galerkin-free POD model for incompressible flows

•A domain decomposition method which couples high and low-fidelity models is proposed to reduce the cost of a flow simulation.•A criteria to perform the splitting of the domain and to perform an optimal coupling between the two models is proposed.•The simplicity and the generality of the method make it potentially suitable for the study of industrially relevant problems.

A domain decomposition method which couples a high and a low-fidelity model is proposed to reduce the computational cost of a flow simulation. This approach requires to solve the high-fidelity model in a small portion of the computational domain while the external field is described by a Galerkin-free Proper Orthogonal Decomposition (POD) model. We propose an error indicator to determine the extent of the interior domain and to perform an optimal coupling between the two models. This zonal approach can be used to study multi-body configurations or to perform detailed local analyses in the framework of shape optimisation problems. The efficiency of the method to perform predictive low-cost simulations is investigated for an unsteady flow and for an aerodynamic shape optimisation problem.

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