Accuracy Improvement Quantification Using Phase-Separated PIV Measurements
F. Gökhan Ergin
Dantec Dynamics, Skovlunde, Denmark
DOI:
This paper aims to quantify the Particle Image Velocimetry (PIV) measurement accuracy improvement along the phase boundaries of two-phase flows, due to the use of phase-separated PIV analysis, compared to conventional PIV analysis without separating the phases. To compute the true error produced by PIV analysis, a patchwork of synthetic image pair with a known displacement is used (ground truth). As real flows might have arbitrary flow direction and magnitude across the phase boundary, the patchwork of image-pair includes a variety of direction combinations, i.e. flows running into each other or away from one another, shear flow, sink flow, flow towards a wall and flow away from a wall, flow running into a stagnant phase, flows with perpendicular directions, and flows that are 45° to each other. The relative error distribution along the boundaries reveals that the relative error level depends on the flow direction on each side of the boundary. Results also indicate that phase-separated PIV measurements can bring the relative error level from ~200% down to ~5% along the boundaries.
