Title: On the universality of anomalous scaling exponents of structure functions in turbulent flows,
Abstract: All previous experiments in open turbulent flows (e.g. downstream of grids,
jet and atmospheric boundary layer) have produced quantitatively consistent
values for the scaling exponents of velocity structure functions. The only
measurement in closed turbulent flow (von Kármán swirling flow) using
Taylor-hypothesis, however, produced scaling exponents that are significantly
smaller, suggesting that the universality of these exponents are broken with
respect to change of large scale geometry of the flow. Here, we report
measurements of longitudinal structure functions of velocity in a von
Kármán setup without the use of Taylor-hypothesis. The measurements are
made using Stereo Particle Image Velocimetry at 4 different ranges of spatial
scales, in order to observe a combined inertial subrange spanning roughly one
and a half order of magnitude. We found scaling exponents (up to 9th order)
that are consistent with values from open turbulent flows, suggesting that they
might be in fact universal.