Wall model for large eddy simulations accounting for particle effect

Abstract

A new wall model is developed for the larger eddy simulation of particle-laden flow over erodible particle bed. To reasonably include particle-related physics in the model, we adopt the assumptions of conserved momentum flux and Prandtl mixing length for turbulent viscosity in the particle-laden flow. The model involves several empirical expressions, such as the non-dimensionlized particle mass flux, the mean particle saltating height and a correction coefficient that is $\sim O\left(1\right)$. The results of wall-resolved large eddy simulation with Lagrangian particle model are taken to be the “standard data” to test the performance of the proposed wall model. Several large eddy simulations without any wall model and with wall models developed for particle-free turbulence are also employed for comparison. The comparisons show that the proposed wall model provides much better predictions of particle statistics to the “standard data” than any other methods. The results of this study highlight the significance of incorporating additional particle effects in the wall model when performing large eddy simulations of particle-laden flow on a coarse grid.