Construction of Full Way Coupling LES for Particle-laden Turbulent Flows Using Dynamic SGS Models.

Abstract

A new method named full way coupling of large eddy simulation for particle-laden turbulent flows using two modified dynamic subgrid scale (SGS) models and considering particles collision based on a Eulerian-Lagrangian approach was presented. In order to simulate the interactions of SGS components, two new SGS models were introduced by report 1 and 2 previously : Dynamic random walk SGS model was used to calculate the particles diffusion by fluid SGS component, and the fluid turbulence modification of particle SGS component has been investigated using a proposed dynamic two way coupling SGS model. The advantage of these new SGS coupling models is that the dimensional analysis coefficient of proposed SGS model could be optimized by Germano's (1991) dynamic procedure. The effects of interparticle collision on particles motion were taken into accounts using direct numerical simulation. Using this full way coupling method, the numerical simulations were performed for downward channel flow at Reynolds numbers of 644 that was identical to the experiments done by Kulick et al. in 1994. The capability and limitation of the full way coupling LES method in predicting particles diffusion and fluid turbulence modification for particle-laden turbulent flows were investigated.