Scalar dispersion by a large-eddy simulation and a Lagrangian stochastic subgrid model

A hybrid Eulerian-Lagrangian large-eddy simulation (LES) is used to compute scalar dispersion in a turbulent flow. Instead of resolving the passive scalar transport equation, fluid particles are tracked in a Lagrangian way. In order to obtain the subgrid scale velocity component of fluid particles, a Lagrangian stochastic subgrid model is coupled with the Eulerian LES. The Lagrangian stochastic subgrid model is written in terms of subgrid scale statistics. The coupling is applied to the study of turbulent scalar dispersion. The results of our simulation are compared with a direct numerical simulation and with experimental results. (c) 2006 American Institute of Physics.