Advanced PIV algorithms with Image Distortion Validation and Comparison using Synthetic Images of Turbulent Flow

In the present paper, two advanced PIV algorithms are described and compared with conventional cross-correlation sub-pixel PIV evaluation techniques. The first algorithm is an iterative continuous windows shift technique (CWS). The second, based on the same correlation and peak-finding techniques, includes an image distortion module to improve measurement of velocity gradients. PIV algorithms are validated and compared using synthetic images, onto which Direct Numerical Simulation (DNS) adds the motion of tracer particles to simulate a turbulent flow with homogeneous and isotropic properties. PIV algorithms are compared and their limitations studied in terms of velocity fluctuations, vorticity field, spectrum or other relevant turbulence parameters. The effect of the out-of-plane motion in 3D turbulent flows and the resulting uncertainties are also investigated.