LAGRANGIAN STATISTICS OF LIGHT SOLID PARTICLE IN A TURBULENCE WITH STRONG EFFECTS OF INTERMITTENCY: SYNTHETIC EDDY SIMULATION APPROACH

摘要

This paper addresses to simulation of a high Reynolds number flow with dispersed light particles. A new numerical approach is proposed in order to get access to the flow structure, which is not resolved by LES approach. Instead of filtered Navier-Stokes equation, the new approach is based on the instantaneous model-equation, where along with resolved acceleration in the gaseous phase, the contribution of subgrid acceleration is modeled stochastically in a way that satisfies the continuity equation. In the limit of zero turbulent viscosity, the model-equation reproduces the instantaneous Navier Stokes equation. The Langevin equation for the subgrid scale velocity increment is used. It is shown that the new approach allows to represent relatively well the velocity spectrum at subgrid scales. This approach is under the development; the first results showed that by accounting for inhomogeneity in the flow at small scales (intermittency), the acceleration of immersed solid particles may be substantially changed.