The effect of particle anisotropy on the modulation of turbulent flows

TL;DR

This study explores how particle shape, specifically isotropic spheres versus anisotropic fibers, differently influences turbulence modulation and energy transfer across scales in turbulent flows.

Contribution

It provides a comparative analysis of how isotropic and anisotropic particles alter turbulence, revealing distinct mechanisms of energy transfer and spectrum modification.

Findings

Both particle types cause large-scale energy depletion at fixed mass fraction.

Bluff objects preserve the classical energy cascade, just scaled down.

Slender objects induce an alternative energy flux mediated by fluid-solid coupling.

Abstract

We investigate the modulation of turbulence caused by the presence of finite-size dispersed particles. Bluff (isotropic) spheres vs slender (anisotropic) fibers are considered to understand the influence of the object shape on altering the carrier flow. While at a fixed mass fraction - but different Stokes number - both objects provide a similar bulk effect characterized by a large-scale energy depletion, a scale-by-scale analysis of the energy transfer reveals that the alteration of the whole spectrum is intrinsically different. For bluff objects, the classical energy cascade is shrinked in its extension but unaltered in the energy content and its typical features, while for slender ones we find an alternative energy flux which is essentially mediated by the fluid-solid coupling.