Detection of turbulent thermal diffusion of particles in numerical simulations
2012 (English)In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 24, no 7, 075106- p.Article in journal (Refereed) Published
The phenomenon of turbulent thermal diffusion in temperature-stratified turbulence causing a non-diffusive turbulent flux (i.e., non-counter-gradient transport) of inertial and non-inertial particles in the direction of the turbulent heat flux is found using direct numerical simulations (DNS). In simulations with and without gravity, this phenomenon is found to cause a peak in the particle number density around the minimum of the mean fluid temperature for Stokes numbers less than 1, where the Stokes number is the ratio of particle Stokes time to turbulent Kolmogorov time at the viscous scale. Turbulent thermal diffusion causes the formation of inhomogeneities in the spatial distribution of inertial particles whose scale is large in comparison with the integral scale of the turbulence. The strength of this effect is maximum for Stokes numbers around unity, and decreases again for larger values. The dynamics of inertial particles is studied using Lagrangian modelling in forced temperature-stratified turbulence, whereas non-inertial particles and the fluid are described using DNS in an Eulerian framework.
Place, publisher, year, edition, pages
2012. Vol. 24, no 7, 075106- p.
Astronomy, Astrophysics and Cosmology
IdentifiersURN: urn:nbn:se:kth:diva-103395DOI: 10.1063/1.4733450ISI: 000308406000035ScopusID: 2-s2.0-84864755965OAI: oai:DiVA.org:kth-103395DiVA: diva2:560045
FunderEU, European Research Council
QC 201210112012-10-112012-10-112013-08-27Bibliographically approved