Prediction of a particle-laden turbulent channel flow: Examination of two classes of stochastic dispersion models

摘要

Nowadays, two families of stochastic models are mainly used to predict the dispersion of inertial particles in inhomogeneous turbulent flows. This first one is named "normalized model" and the second one "Generalized Langevin Model (GLM)". Nevertheless, the main differences between the normalized and GLM models have not been thoroughly investigated. Is there a model which is more suitable to predict the particle dispersion in inhomogeneous turbulence? We propose in the present study to clarify this point by computing a particle-laden turbulent channel flow using a GLM-type model, and also a normalized- type model. Particle statistics (such as concentration, mean and rms particle velocity, fluid-particle velocity covariances) will be provided and compared to Direct Numerical Simulation (DNS) data in order to assess the performance of both dispersion models. It will be shown that the normalized dispersion model studied can predict correctly the effect of particle inertia on some dispersion statistics, but not on all. For instance, it was found that the prediction of the particle kinetic shear stress and some components of the fluid-particle covariance is not physically acceptable.