Vorticity-strain rate dynamics and the smallest scales of turbulence

TL;DR

This paper introduces a framework based on Navier-Stokes properties to quantify extreme events and smallest scales in turbulence, aligning well with high-Reynolds-number simulation data and highlighting the importance of vorticity-strain correlations.

Contribution

It presents a novel, simple framework for analyzing turbulence scales that emphasizes the role of vorticity-strain correlations, improving understanding of intermittency.

Findings

Framework agrees with DNS data up to Re=1300

Highlights shortcomings of existing intermittency models

Emphasizes importance of vorticity-strain correlation

Abstract

Building upon the intrinsic properties of Navier-Stokes dynamics, namely the prevalence of intense vortical structures and the interrelationship between vorticity and strain rate, we propose a simple framework to quantify the extreme events and the smallest scales of turbulence. We demonstrate that our approach is in excellent agreement with the best available data from direct numerical simulations of isotropic turbulence, with Taylor-scale Reynolds number up to 1300. We additionally highlight a shortcoming of prevailing intermittency models due to their disconnection from observed correlation between vorticity and strain. Our work accentuates the importance of this correlation as a crucial step in developing an accurate understanding of intermittency in turbulence.