Current capabilities of Large-Eddy Simulation (LES) in Eulerian-Lagrangian studies of dispersed flows are limited by the modeling of the Sub-Grid Scale (SGS) turbulence effects on particle dynamics. In this paper, the possibility is examined to account explicitly for SGS effects by incorporating ad-hoc closure models in the Lagrangian equations of particle motion. Specifically, a candidate model based on approximate deconvolution is considered and applied to particle-laden turbulent channel flow. Results show that, even if the fraction of SGS turbulent kinetic energy for the fluid velocity field (not resolved in LES) is recovered, quantitative prediction of local segregation and, in turn, of near-wall accumulation may still be inaccurate. This failure indicates that reconstructing the correct amount of fluid and particle velocity fluctuations is not enough to reproduce the effect of SGS turbulence on particles and that further information on the flow structure at the sub-grid scales must be incorporated.
Inertial particle segregation and deposition in large-eddy simulation of turbulent wall-bounded flows
SALVETTI, MARIA VITTORIA;
2011-01-01
Abstract
Current capabilities of Large-Eddy Simulation (LES) in Eulerian-Lagrangian studies of dispersed flows are limited by the modeling of the Sub-Grid Scale (SGS) turbulence effects on particle dynamics. In this paper, the possibility is examined to account explicitly for SGS effects by incorporating ad-hoc closure models in the Lagrangian equations of particle motion. Specifically, a candidate model based on approximate deconvolution is considered and applied to particle-laden turbulent channel flow. Results show that, even if the fraction of SGS turbulent kinetic energy for the fluid velocity field (not resolved in LES) is recovered, quantitative prediction of local segregation and, in turn, of near-wall accumulation may still be inaccurate. This failure indicates that reconstructing the correct amount of fluid and particle velocity fluctuations is not enough to reproduce the effect of SGS turbulence on particles and that further information on the flow structure at the sub-grid scales must be incorporated.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
