The present study aims to identify and characterize large-scale, canonical flow patterns in turbulent swirling flows based on high-speed (10 kHz), dual-plane, stereoscopic PIV (DP-s-PIV) measurements, which enable complete determination of the nine-component velocity-gradient tensor and the three vortical components. To identify and isolate large flow structures, a piecewise, least-mean-square, smoothing scheme is developed to filter out velocity perturbations and high velocity gradients associated with small vortices and the intrinsic measurement noise. Interactions between the vortex rings and those between the vortex rings and the precessing vortex core (PVC) are resolved and analyzed.
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