Universal intermittent properties of particle trajectories in highly turbulent flows

TL;DR

This study demonstrates universal intermittent properties in particle trajectories across various turbulent flows, supported by experimental and numerical data, and explains these phenomena using an extended multifractal theory.

Contribution

It provides the first comprehensive evidence of universal Lagrangian intermittency in turbulence and extends multifractal theory to describe these properties across multiple scales.

Findings

Lagrangian structure functions collapse onto a universal curve

Multifractal theory accurately models intermittency across scales

Data from diverse flows show consistent statistical behavior

Abstract

We present a collection of eight data sets, from state-of-the-art experiments and numerical simulations on turbulent velocity statistics along particle trajectories obtained in different flows with Reynolds numbers in the range $R_\lambda \in [120:740]$. Lagrangian structure functions from all data sets are found to collapse onto each other on a wide range of time lags, revealing a universal statistics, and calling for a unified theoretical description. Parisi-Frisch Multifractal theory, suitable extended to the dissipative scales and to the Lagrangian domain, is found to capture intermittency of velocity statistics over the whole three decades of temporal scales here investigated.