Investigation of accelerated flow over an airfoil at an angle of attack using multigrid cross-correlation digital PIV

Abstract

A preliminary study has been undertaken to investigate the evolution and structure of flow accelerated from a stationary state over a NACA 0015 airfoil at an angle of attack of 30°. Two uniform accelerations of 50mm/s 2 and 100mm/s2 were employed. The final uniform velocity was the same for both cases, 100 mm/s. The Reynolds number based on this uniform velocity and the chord length of the airfoil was 8000. PIV measurements were carried out using a digital high resolution CCD camera to record single exposed images of seed particles illuminated using a Nd:YAG laser. The single exposed images were analysed using multigrid cross-correlation digital PIV analysis. These measurements have revealed a rich and complex unsteady flow structure.