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

Abstract

Experiments and numerical computations have highlighted that heavy particles entrained in wall-bounded (e.g. nonhomogeneous) turbulent flows tend to attain a nonuniform distribution in the normal-to-the-wall direction, with higher concentrations near the wall. Recently, a Eulerian model for predicting particle deposition rates that explains the experimental observations on the basis of turbophoretic force was presented. This force causes particles to gain a net drift velocity down the gradients of turbulence intensities. In this paper, we investigate the feasibility of the Eulerian approach for modeling the phenomenology of turbulent dispersion in pipe flow with reflecting walls. Model predictions are compared with original results obtained through direct numerical simulations (DNS) and Lagrangian particle tracking in a turbulent pipe flow ( Re=4900). We show that the direct implementation 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 particle momentum balance equation. A better agreement (order of magnitude) between DNS results and model predictions is found.