Self-organization and Nonuniversal Anomalous Scaling in Non-Newtonian Turbulence

TL;DR

This paper uses DNS to explore how non-Newtonian fluids affect turbulence, revealing self-organization at microscopic scales and nonuniversal anomalous scaling related to rheological properties.

Contribution

It demonstrates the self-organized vortex size distribution and nonuniversal anomalous scaling in non-Newtonian turbulence, extending understanding beyond classical theories.

Findings

Vortex size distribution shows structural invariance due to self-organization.

Deviations from K41 theory indicate nonuniversal anomalous scaling.

Rheological properties influence turbulence statistics.

Abstract

We investigate through Direct Numerical Simulations (DNS) the statistical properties of turbulent flows in the inertial subrange for non-Newtonian power-law fluids. The structural invariance found for the vortex size distribution is achieved through a self-organized mechanism at the microscopic scale of the turbulent motion that adjusts, according to the rheological properties of the fluid, the ratio between the viscous dissipations inside and outside the vortices. Moreover, the deviations from the K41 theory of the structure functions' exponents reveal that the anomalous scaling exhibits a systematic nonuniversal behavior with respect to the rheological properties of the fluids.