Turbulent transport of finite sized material particles

Abstract

Turbulent transport of material inclusions plays an important role in many natural and industrial situations. In the present study, we report an exhaustive experimental investigation of Lagrangian dynamics of material particles in a turbulent airflow, over a wide range of sizes and densities. For fixed carrier flow conditions, we find that (i) velocity statistics are not affected by particles inertia; (ii) acceleration statistics have a very robust signature, where only acceleration variance is affected by inertia; (iii) inertial particles always have an intermittent dynamics; (iv) intermittency signature depends on particles inertia; (v) particles actual response time to turbulent forcing remains essentially of the order of the carrier flow dissipation time rather than any particles dependent time (as the Stokes time for instance). These observations are in contrast with usual predictions from Stokesian models for point particles.