DOI: 10.1615/ICHMT.2009.TurbulHeatMassTransf
ISBN Print: 978-1-56700-262-1
ISSN: 2377-2816
Large scale accumulation patterns of inertial particles in wall-bounded turbulent flow
ABSTRAKT
Spatially inhomogeneous turbulent flows induce peculiar phenomena on the transport on the transport of a dispersed phase of inertial particles. In wall bounded flow the most striking effect os the spatial segregation of particles with suitable inertia which may achieve a concentration in the wall region exceeding thousand times the concentration in the bulk. This turbulence induced migration, turbophoresis, have a significant impact on a technological process typical of engineering. Here we approach the issue by considering direct numerical (DNS) of turbulent pipe and channel flows seeded with different populations of diluted, tiny particles. Two specific issues are stressed ; namely the spatial developing of the accumulation process and the patterns of streaky structures that the particles segregate in the near wall region. It is found that the transient phase of accumulation is well described in terms of a suitable entropy function associated with the particle distribution. The structures found in the fully developed stage of the process show strong spanwise correlations more intense than that found in the corresponding elongated structures of low and high fluid speed.