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Abstract: We study the statistical properties of coherent, small-scales,filamentary-like structures in Turbulence. In order to follow in time suchcomplex spatial structures, we integrate Lagrangian and Eulerian measurementsby seeding the flow with light particles. We show that light particlespreferentially concentrate in small filamentary regions of high persistentvorticity vortex filaments. We measure the fractal dimension of theattracting set and the probability that two particles do not separate for longtime lapses. We fortify the signal-to-noise ratio by exploiting multi-particlescorrelations on the dynamics of bunches of particles. In doing that, we areable to give a first quantitative estimation of the vortex-filamentslife-times, showing the presence of events as long as the integral correlationtime. The same technique introduced here could be used in experiments as longas one is capable to track clouds of bubbles in turbulence for a relativelylong period of time, at high Reynolds numbers; shading light on the dynamics ofsmall-scale vorticity in realistic turbulent flows.

Author: Luca Biferale, Andrea Scagliarini, Federico Toschi



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