ADE approach to predicting dispersion of heavy particles in wall-bounded turbulence

Experiments and numerical computations have highlighted that heavy particle s entrained in wall-bounded (e.g. nonhomogeneous) turbulent flows tend to a ttain a nonuniform distribution in the normal-to-the-wall direction, with h igher concentrations near the wall. Recently, a Eulerian model for predicti ng particle deposition rates that explains the experimental observations on the basis of turbophoretic force was presented. This force causes particle s to gain a net drift velocity down the gradients of turbulence intensities . In this paper, we investigate the feasibility of the Eulerian approach fo r modeling the phenomenology of turbulent dispersion in pipe flow with refl ecting walls. Model predictions are compared with original results obtained through direct numerical simulations (DNS) and Lagrangian particle trackin g in a turbulent pipe flow (Re = 4900). We show that the direct implementat ion of the model proposed recently tends to overpredict concentration peaks at the pipe wall, a trend that had already been observed in the context of deposition theory (perfectly absorbing wall). We propose a modified model for computing turbophoretic. drift velocity by providing an estimate for a term that was considered negligible in the original formulation of the part icle momentum balance equation. A better agreement (order of magnitude) bet ween DNS results and model predictions is found. (C) 2001 Elsevier Science Ltd. All rights reserved.