Statistical analysis and accuracy of PIV data

In an assessment of PIV measurement accuracy under practical experimental circumstances, grid-generated turbulence in its early decay (x/M = 13.6-15.2, Re_l a 25) has been studied. Since a real-time processor was used, it was practical to acquire a statistically significant sample size of 3000 vector maps so that accurate turbulence statistics could be calculated. Results include moments of velocity components and spatial structures in terms of auto-correlations, turbulence scales and spectra. Data fall within limits of standard error estimates. This study demonstrates the need for large sample sizes, particularly for higher order statistics.