Vorticity-Strain Rate Dynamics and the Smallest Scales of Turbulence.

Dhawal Buaria,Alain Pumir

doi:10.1103/physrevlett.128.094501

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 numbers up to 1300. We additionally highlight a shortcoming of prevailing intermittency models due to their disconnection from the 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.

Highlights

A defining property of fluid turbulence is the presence of a wide range of dynamically interacting scales that is bounded from above by the largest scales, which are of the order of flow dimension, and from below by the smallest scales, determined by the diffusive action of molecular viscosity
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 numbers up to 1300

Summary

Introduction

A defining property of fluid turbulence is the presence of a wide range of dynamically interacting scales that is bounded from above by the largest scales, which are of the order of flow dimension, and from below by the smallest scales, determined by the diffusive action of molecular viscosity. Vorticity-Strain Rate Dynamics and the Smallest Scales of Turbulence 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.

Results

Conclusion