Acceleration statistics of finite-sized particles in turbulent flow: the role of Faxen forces

TL;DR

This paper investigates how finite-sized particles behave in turbulent flows, demonstrating that including Faxen forces in models better captures experimental observations of particle acceleration and correlation times.

Contribution

The study introduces Faxen corrections into particle models, improving the accuracy of simulations for finite-sized particles in turbulence compared to traditional point particle models.

Findings

Acceleration variance decreases with particle size

Correlation times increase with particle size

Normalized acceleration PDFs become size-independent

Abstract

The dynamics of particles in turbulence when the particle-size is larger than the dissipative scale of the carrier flow is studied. Recent experiments have highlighted signatures of particles finiteness on their statistical properties, namely a decrease of their acceleration variance, an increase of correlation times -at increasing the particles size- and an independence of the probability density function of the acceleration once normalized to their variance. These effects are not captured by point particle models. By means of a detailed comparison between numerical simulations and experimental data, we show that a more accurate model is obtained once Faxen corrections are included.