격자볼츠만법에서 Dynamic SGS eddy viscosity 모델을 이용한 높은 Reynolds 수에서 Backward facing step 유동 연구

Abstract

The Lattice Boltzmann method has recently been used to simulate fluid flows. However, most flow simulations are performed in low Reynolds number laminar regime. In this work, we use the Lattice Boltzmann subgrid model and Dynamic SGS eddy viscosity model to extend the range of Reynolds number up to turbulent flow regime. First, the method is verified to a two-dimensional channel flow. After that, we simulate a high Reynolds number (Re=132,000) turbulent flow past a backward facing step. Two models with the expansion ratio of 3:2 are simulated for Re=132,000. The informations of the fully developed channel flows are used for inlet conditions. We examine the results from simulations of on coarse grids in which the near-wall regions are not resolved and are instead represented by approximate wall boundary conditions. Finally, the simulation results are compared with the corresponding experimental and other numerical results.