Large Eddy Simulation of Turbulence Via Lattice Boltzmann Based Approach: Fundamental Physics and Practical Applications

Abstract

Direct numerical simulations (DNS) via Navier-Stokes equation is adequate for Newtonian fluid flows at macroscopic scales including high Reynolds number turbulence. On the other hand, we argue that the large eddy simulations (LES) of turbulent flows is better achieved physically via Boltzmann equation based kinetic formulations and the lattice Boltzmann method (LB). Among other features compared to the Navier-Stokes based approach, the major differences in the alternative approach include 1) Realization of higher order turbulent eddy effects; and 2) Realization of physical boundary conditions. As a numerical method, LB has shown to be advantageous in doing LES involving complex geometries and flow fields, and it allows for accurate and efficient simulations of time dependent turbulent flows with potentially relatively simpler turbulence models. In this presentation, the fundamental concept of the kinetic based approach for LES will be introduced. Various numerical results on basic turbulent benchmark flows as well as on practical engineering flow problems will also be shown.