Abo Bibliothek: Guest
TSFP DL Home Archive Vorstand

TURBULENCE MODIFICATION IN POLYDISPERSE, WALL-BOUNDED TURBULENCE

David Richter
Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame Notre Dame, IN, USA

Omar Garcia
Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame Notre Dame, IN, USA

Christopher Astephen
Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame Notre Dame, IN, USA

Abstrakt

Direct numerical simulations of turbulent planar Couette flow are performed with Lagrangian point particles chosen to represent noninteracting, two-way coupled particles in low volume concentration, moderate mass concentration systems. Specifically, the behavior of polydisperse mixtures of small particles in wall-bounded turbulent flow is examined in terms of the ability of the dispersed phase to carry momentum alongside (and in place of) the turbulent carrier-phase Reynolds stress. It is shown that for binary mixtures of particles with distinct Stokes numbers, particle stresses are nearly additive, indicating that the presence of one size of particle does not influence the ability of another to couple with the flow. This result is generalized by performing an additional simulation with a continuous distribution of particle size, where it is again suggested that particles with acceleration timescales near that of the Reynoldsstress- producing motions at the wall dominate the balance, and that particles with larger Stokes numbers are similar in their limited ability to carry momentum across the domain. In the context of the low volume concentration, small particle assumptions, this has favorable consequences for modeling efforts.