3-DIMENSIONAL PARTICLE IMAGE VELOCIMETRY - ERROR ANALYSIS OF STEREOSCOPIC TECHNIQUES

A geometric error model for analysis and design of stereoscopic PIV sy stems is presented. The model allows displacement errors in either tra nslational or angular systems to be analysed for any given angle or ca mera separation and for any off-axis position. A parameter for the ana lysis of the system performance is also introduced based on the ratio of out-of-plane to in-plane errors. This is subsequently used to inves tigate the relative performance of translational and angular PIV syste ms for camera angles up to 45 degrees and camera separations of half t he object distance. Results from this analysis show similar trends in centreline characteristics for both types of stereo systems but differ ent trends in off-axis error ratios due to imaging geometry. The resul ts have also suggested that a CCD-based angular PIV stereo system offe rs up to 40% greater out-of-plane accuracy for a given field of view a nd laser power than previous translational systems.