Reduction of Triadic Interactions Suppresses Intermittency and Anomalous Dissipation in Turbulence

TL;DR

This study shows that reducing the triadic interactions in turbulence models suppresses intermittency and anomalous dissipation, indicating these phenomena depend on the full interaction network.

Contribution

It demonstrates that anomalous dissipation and intermittency in turbulence depend on the complete triadic interaction network, challenging previous assumptions.

Findings

Suppression of intermittency with decimation

Vanishing mean dissipation at high Reynolds number

Structure-function exponents revert to dimensional values

Abstract

We investigate how the defining statistical features of three-dimensional turbulence respond to systematic reductions of the Fourier-space triadic interaction network. Using direct numerical simulations of both fractally and homogeneously decimated Navier-Stokes dynamics, we show that progressive thinning of the set of active modes leads to a systematic suppression of intermittency and, most strikingly, to the vanishing of the mean dissipation rate in the large-Reynolds-number limit. Structure-function exponents collapse onto their dimensional values, the multifractal singularity spectrum contracts, and the analyticity width extracted from the exponential spectral tail increases monotonically with decimation-each indicating a substantial regularization of the velocity field. Together, these results provide direct evidence that anomalous dissipation in incompressible turbulence is not a generic property of the Navier-Stokes equations, but instead requires the full combinatorial richness of their triadic nonlinear interactions.