Thermal Fluctuations in the Dissipation Range of Homogeneous Isotropic Turbulence

TL;DR

This paper explores how thermal fluctuations influence the energy spectrum in the dissipation range of homogeneous isotropic turbulence, revealing a dominance at small scales and a transition to Gaussian behavior.

Contribution

It demonstrates through simulations that thermal fluctuations dominate the dissipation range and alter the intermittency predicted by Kraichnan, providing new insights into turbulence at small scales.

Findings

Thermal fluctuations dominate the energy spectrum at Kolmogorov length scales.

Gaussian thermal equipartition replaces extreme intermittency in the far-dissipation range.

Simulation results confirm theoretical predictions about thermal effects in turbulence.

Abstract

Using fluctuating hydrodynamics we investigate the effect of thermal fluctuations in the dissipation range of homogeneous, isotropic turbulence. Simulations confirm theoretical predictions that the energy spectrum is dominated by these fluctuations at length scales comparable to the Kolmogorov length. We also find that the extreme intermittency in the far-dissipation range predicted by Kraichnan is replaced by Gaussian thermal equipartition.