Spectral characteristics of eddy interaction models

The eddy interaction model (EIM) is in common use in simulations of turbule nt particulate flow. In the model, particle motions are determined by inter actions with random-velocity fluid eddies. Spatial and temporal velocity au tocorrelations land therefore wave number and frequency spectral are charac terised by the probability distributions of the velocity, length and time s cales of the eddies. In this paper, spectral behaviour of both standard and modified EIMs is examined. The whole range of behaviours of the EIM, chara cterised by polynomial velocity autocorrelation functions, is studied. It i s shown that each of the resulting spectra exhibits unphysical characterist ics. Consequences for modelling are discussed briefly. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.