Airfoil CFD pressure coefficient modification method based on layered interpolation

Due to actors such as calculation grid resolution, numerical discretization error, and turbulence model adaptability, obvious deviation often exist between CFD predicted pressure data and experimental pressure data. It is thus risky to directly use CFD predicted pressure data to carry out structural strength or aeroelastic analysis. To solve the problem of insufficient precision and large error of traditional single interpolation method when dealing with the pressure coefficient modified of discontinuous changes of suction peak and shock wave position, this paper develops a method for correcting airfoil CFD pressure data based on hierarchical interpolation, enabling high accuracy and high resolution pressure distribution reconstruction. Firstly, the difference between the pressure distribution data at the test point and the pressure distribution data predicted by CFD is calculated by linear interpolation, and then the difference is decomposed into continuous smooth part and discontinuous part by Laplace fairing method. The continuous smooth part of pressure difference is processed by high-order interpolation, and the discontinuous smooth part is processed by linear interpolation. If there is still warpage in the pressure data near the shock wave position after interpolation, the warped part will be smoothed by shock position detection and local position linear interpolation. The method is tested using the RAE2822 airfoil test and CFD computed pressure data, and applied to the DLR-F6 wing-body assembly and HIRENASD wing computed pressure coefficient modified. Results from both test and application show that the delamination pressure data modified method achieves high accuracy, and can obtain more accurate modified results even under the condition of less pressure test measurement points.