Particle-laden two-dimensional elastic turbulence

TL;DR

This study investigates how heavy inertial particles distribute in elastic turbulence of an Oldroyd-B fluid, revealing preferential accumulation on elastic waves and turbophoretic segregation, with effects influenced by particle inertia and flow elasticity.

Contribution

It provides a detailed numerical analysis of particle aggregation in elastic turbulence, highlighting the role of flow structures and inertia in particle clustering and segregation.

Findings

Particles accumulate on elastic waves at intermediate inertia.

Clustering characterized by correlation dimension close to 1.

Flow elasticity slightly reduces turbophoretic segregation.

Abstract

The aggregation properties of heavy inertial particles in the elastic turbulence regime of an Oldroyd-B fluid with periodic Kolmogorov mean flow are investigated by means of extensive numerical simulations in two dimensions. Both the small and large scale features of the resulting inhomogeneous particle distribution are examined, focusing on their connection with the properties of the advecting viscoelastic flow. We find that particles preferentially accumulate on thin highly elastic propagating waves and that this effect is largest for intermediate values of particle inertia. We provide a quantitative characterization of this phenomenon that allows to relate it to the accumulation of particles in filamentary highly strained flow regions producing clusters of correlation dimension close to 1. At larger scales, particles are found to undergo turbophoretic-like segregation. Indeed, our results indicate a close relationship between the profiles of particle density and fluid velocity fluctuations. The large-scale inhomogeneity of the particle distribution is interpreted in the framework of a model derived in the limit of small, but finite, particle inertia. The qualitative characteristics of different observables are, to a good extent, independent of the flow elasticity. When increased, the latter is found, however, to slightly reduce the globally averaged degree of turbophoretic unmixing.