Integrated application of PIV and PSP in large aircraft wind tunnel test

The accuracy of measurement techniques in wind tunnels holds utmost significance in ensuring reliable test outcomes. The present study delves into the accuracy levels of a high-frequency particle image velocimetry (PIV) system in the FL-61 wind tunnel. The results indicate that the PIV system's measurement accuracy surpasses 1% within a freestream velocity range from 30 m/s to 280 m/s. Moreover, the influence of pressure-sensitive paint (PSP) coating on force and pressure measurement tests was also investigated, utilizing polyimide films with varying thicknesses and roughnesses as PSP coatings. It is found that a PSP coating with a thickness of less than 0.03 mm is imperative to obtain reliable force and pressure data. Furthermore, an experimental study of a civil aircraft calibration model was conducted in the FL-62 continuous transonic wind tunnel by acquiring PIV and PSP data at extremely short temporal intervals. The quasi-synchronous integration of PIV and PSP provides the three-dimensional velocity fields over the wing and surface pressure for the aerodynamic performance evaluation.