Reconstitution de trajectoires de particules solides sur la base d'un modèle de turbulence

Particle trajectories modelling based on a standard model of turbulence

¹ CEMAGREF, Lyon
² IMG, Grenoble

Abstract

Most of the suspension modellings work on concentrations, the solid phase being considered as a continuous state governed by convection and diffusion equations; on the contrary, the numerical model presented here is based on a particle approach of suspension: the trajectory of a solid particle is built timestep after timestep, using the dynamic equation of a solid particle in a fluid flow; an important difficulty is to rebuild, at each timestep, the fluid velocity field surrounding the solid particle.

A method of "lagrangian generation of local turbulent field" (adapted from Des jonquères 87) is presented here, which simulates fluid trajectories in conserving lagrangian velocity correlations, and then calculates the solid particle trajectories. We suggest a method for simulating the behaviour of relatively heavy solid particles in the boundary layer, taking the "slipping effect" (mainly due to the bursting process) into account.