A proper orthogonal decomposition (POD)method is used to interpolate the flow around an airfoil for variousMach numbers and\r\nangles of attack in the transonic regime. POD uses a few numerical simulations, called snapshots, to create eigenfunctions. These\r\neigenfunctions are combined using weighting coefficients to create a new solution for different values of the input parameters. Since\r\nPOD methods are linear, their interpolation capabilities are quite limited when dealing with flow presenting nonlinearities, such\r\nas shocks. In order to improve their performance for cases involving shocks, a new method is proposed using variable fidelity.\r\nThe main idea is to use POD to interpolate the difference between the CFD solution obtained on two different grids, a coarse one\r\nand a fine one.Then, for any new input parameter value, a coarse grid solution is computed using CFD and the POD interpolated\r\ndifference is added to predict the fine grid solution. This allows some nonlinearities associated with the flow to be introduced.\r\nResults for various Mach numbers and angles of attack are compared to full CFD results. The variable fidelity-based POD method\r\nshows good improvement over the classical approach.
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