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Dynamics of Brownian particles in a turbulent channel flow

Författare:	Fukagata, K., Zahrai, S., Bark, F.H.
Dokumenttyp:	Artikel
Tillstånd:	Publicerad
Tidskrift:	Heat Mass Transfer
Volym:	40 715-726
År:	2004

Abstract

Turbulent channel flows with suspended particles are investigated by means of numerical simulations. The fluid velocity is computed by large eddy simulation. Motion of small graphite particles with diameter of 0.01 - 10 micron, corresponding to the Schmidt number, Sc, of 2.87 x 10 ² - 6.22 x 10 ⁶ and the particle relaxation time in wall unit, t _p ⁺, of 9.79 x 10 ^-5 - 4.51, is computed by Lagrangian particle tracking. Relation between the particle relaxation time and the computed deposition velocity is found to be in good agreement with an empirical relation suggested by Wood (1981) and simulation results by Li and Ahmadi (1993). The statistics of the particle motion in the vicinity of the wall are studied. Clear differences are found in dynamical behavior of particles with different sizes. Medium size particles show a strong dependence on the structure of the fluid flow, while small and large particles are considerably less sensitive.