Identifying Sources of Stereoscopic PIV Measurements Errors on Turbulent Round Jets

This paper addresses some hurdles in experimental data acquisition and analysis when sampling an axisymmetric flow in Cartesian coordinates. The problems are illustrated using recent SPIV data taken in the far field of a turbulent round jet in air. Discrepancies became apparent when trying to reconstruct the polar coordinate moments from Cartesian ones, since both components of the in-plane moments of the latter must be measured to within the same relative accuracy in order to recover the axisymmetry. Various sources for the observed discrepancies are considered including differential resolution of the Cartesian components, peak-locking and misregistration in the stereoscopic recombination. The last seems to be the most important one.