Quantification of heavy particles segregation in turbulent flows: a Lagrangian approach

Preferential concentration of particles in turbulence is studied numerically by quantifying the Lagrangian compressibility of the particulate phase. The compressibility of the particle velocity field predicted by the "Full Lagrangian method" (Osiptsov 1984) is compared with the mesoscopic Eulerian particle velocity field (Fevrier et al. 2005) both in a direct numerical simulation of turbulence and in a synthetic flow field. We demonstrate that the Lagrangian method, in contrast to the Eulerian, accurately predicts the compressibility of the particle velocity field even when the latter is characterized by singularities. Results show that the particle clustering occurs predominantly in regions where the particle velocity field is compressed.