Improved airfoil inverse design method based on Gappy POD

To improve the design accuracy of airfoils, a new sample method called the best snapshot replacement is proposed in this paper which is used during the sampling process of airfoil inverse design based on Gappy proper orthogonal decomposition (POD). Using this method, the baseline airfoil has to be replaced by an airfoil whose pressure distribution is closest to the target pressure distribution among the airfoils that have been generated. During the iteration process, a calibration step is added based on the principle that a calibration snapshot can be introduced. By the fitting error of pressure distribution estimated by POD. Then the target pressure distribution can be calibrated using this snapshot. Airfoil inverse design examples demonstrate that the new sample method can generate a set of snapshots which spans a space closer to the design target. Compared with the original method this calibration iteration method can improve the accuracy of design result obviously, while how to choose the optimal number of modes remains to be a difficult point for airfoil inverse design based on Gappy POD.