The effect of particle anisotropy on the modulation of turbulent flows

We investigate the modulation of turbulence caused by the presence of finite-size dispersed particles. Bluff (isotropic) spheres versus slender (anisotropic) fibres are considered to understand the influence of the shape of the objects 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 shrinks in its extension but is 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.

Automated summary

This study investigates the modulation of turbulence caused by the presence of finite-size dispersed particles. Bluff (isotropic) spheres and slender (anisotropic) fibres are compared to understand how the shape of the objects influences the carrier flow. While both objects, at a fixed mass fraction but different Stokes number, lead to similar bulk effects characterized by large-scale energy depletion, a scale-by-scale analysis reveals intrinsic differences in the alteration of the whole spectrum. For bluff objects, the classical energy cascade shrinks in its extension but retains its energy content and typical features, while for slender objects, an alternative energy flux mediated by fluid-solid coupling is found.