PIV Uncertainty: Computational and Experimental Evaluation of the Peak Ratio Method

Uncertainty quantification for planar PIV remains a challenging task. In the present study, we assess three methods that were recently described in the literature: primary peak ratio (PPR), mutual information (MI), and image matching (IM). Each method was used to calculate the uncertainty in a synthetic turbulent boundary layer flow and an experimental jet flow. In the experimental case, two PIV systems with common fields of view were used — one with a high dynamic range (which was considered as the true solution) and another with a magnification ratio of about four times less (which was considered the measurand). The high resolution PIV system was verified by comparing velocity records at a point with an LDV measurement system. PIV processing was performed with PRANA and Insight4G. In regards to the experimental flow, the PPR method performed best, followed by mutual information, and lastly image matching. This was due to better responses by PPR and MI of uncertainty to the spatially varying error distribution. Similar conclusions were made with respect to the synthetic test case.