Three-dimensional particle image velocimetry: a low-cost 35 mm angular stereoscopic system for liquid flows

摘要

A low-cost 35 mm PIV stereoscopic system for liquid flows is presented which has an imaging component cost under US$9000. The system uses an angular configuration, rotating mirror image shifting and in-situ calibration techniques. Image processing algorithms based on cross correlation and bicubic interpolation are also used to calculate the 3D data from the PIV images. Results from an error analysis have shown the system to have in plane errors ranging from 4.15 to 5.95 and out of plane errors of 7.01 providing an f-number of f 22 is fixed for all imaging. Subsequent application of the system to a flow field generated by a free falling sphere in wheat syrup have produced results which when compared to previous flow visualisation give good qualitative agreement. Suggested improvements to the PIV system costing US$1300 would allow operation at f-numbers down to f8 by modifying the cameras for the Schemipflug condition and using a corrective liquid prism.