Acceleration of heavy and light particles in turbulence: comparison between experiments and direct numerical simulations

TL;DR

This study compares experimental and numerical data on how inertial particles of different densities accelerate in turbulent flows, highlighting the agreement and discrepancies in their dynamic behaviors.

Contribution

The paper provides a direct comparison between experimental measurements and numerical simulations of inertial particle dynamics in turbulence, focusing on acceleration statistics.

Findings

Good agreement in acceleration variance and autocorrelation timescales

Small discrepancies in acceleration PDF shape

Finite particle size effects are discussed

Abstract

We compare experimental data and numerical simulations for the dynamics of inertial particles with finite density in turbulence. In the experiment, bubbles and solid particles are optically tracked in a turbulent flow of water using an Extended Laser Doppler Velocimetry technique. The probability density functions (PDF) of particle accelerations and their auto-correlation in time are computed. Numerical results are obtained from a direct numerical simulation in which a suspension of passive pointwise particles is tracked, with the same finite density and the same response time as in the experiment. We observe a good agreement for both the variance of acceleration and the autocorrelation timescale of the dynamics; small discrepancies on the shape of the acceleration PDF are observed. We discuss the effects induced by the finite size of the particles, not taken into account in the present numerical simulations.