Numerical methods for low‐order modeling of fluid flows based on POD

This paper explores some numerical alternatives that can be exploited to derive efficient low‐order models of the Navier–Stokes equations. It is shown that an optimal solution sampling can be derived using appropriate norms of the Navier–Stokes residuals. Then the classical Galerkin approach is derived in the context of a residual minimization method that is similar to variational multiscale modeling. Finally, calibration techniques are reviewed and applied to the computation of unsteady aerodynamic forces. Examples pertaining to both non‐actuated and actuated flows are shown.