Anisotropy in Pair Dispersion of Inertial Particles in Turbulent Channel Flow
| Autor: | Alfredo Soldati, Enrico Pitton, Valentina Lavezzo, Cristian Marchioli, Federico Toschi |
|---|---|
| Přispěvatelé: | Fluids and Flows, Scientific Computing, Computational Multiscale Transport Phenomena (Toschi) |
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Fluid Flow and Transfer Processes
Physics Turbulence Chézy formula Mechanical Engineering media_common.quotation_subject Computational Mechanics Direct numerical simulation Reynolds number Mechanics Condensed Matter Physics Inertia Open-channel flow Physics::Fluid Dynamics symbols.namesake Flow separation Mechanics of Materials symbols Two-phase flow Statistical physics media_common |
| Zdroj: | Physics of Fluids, 24(7):073305, 073305-1/25. American Institute of Physics Physics of fluids (Melville N.Y.) 24 (2012): 073305. doi:10.1063/1.4737655 info:cnr-pdr/source/autori:Enrico Pitton, Cristian Marchioli, Valentina Lavezzo, Alfredo Soldati and Federico Toschi/titolo:Anisotropy in pair dispersion of inertial particles in turbulent channel flow/doi:10.1063%2F1.4737655/rivista:Physics of fluids (Melville N.Y.)/anno:2012/pagina_da:073305/pagina_a:/intervallo_pagine:073305/volume:24 |
| ISSN: | 1070-6631 |
| DOI: | 10.1063/1.4737655 |
| Popis: | The rate at which two particles separate in turbulent flows is of central importance to predict the inhomogeneities of particle spatial distribution and to characterize mixing. Pair separation is analyzed for the specific case of small, inertial particles in turbulent channel flow to examine the role of mean shear and small-scale turbulent velocity fluctuations. To this aim an Eulerian-Lagrangian approach based on pseudo-spectral direct numerical simulation (DNS) of fully developed gas-solid flow at shear Reynolds number Ret = 150 is used. Pair separation statistics have been computed for particles with different inertia (and for inertialess tracers) released from different regions of the channel. Results confirm that shear-induced effects predominate when the pair separation distance becomes comparable to the largest scale of the flow. Results also reveal the fundamental role played by particles-turbulence interaction at the small scales in triggering separation during the initial stages of pair dispersion. These findings are discussed examining Lagrangian observables, including the mean square separation, which provide prima facie evidence that pair dispersion in non-homogeneous anisotropic turbulence has a superdiffusive nature and may generate non-Gaussian number density distributions of both particles and tracers. These features appear to persist even when the effects of shear dispersion are filtered out, and exhibit strong dependency on particle inertia. Application of present results is discussed in the context of modelling approaches for particle dispersion in wall-bounded turbulent flows. |
| Databáze: | OpenAIRE |
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