利用LES法研究矩形管道流場之變化

Abstract

本文目的主要利用有限差分數值方法探討可壓縮流體的紊流三維渠道流場。採用LES模式計算雷諾應力項，非黏滯性項則用Roe scheme計算。並利用Preconditioning法增加計算的收斂速度，使得不論在高速或低速流區域均可求得正確結果。探討所得之雷諾應力分布，平均速度分布之變化，並和以往結果比較。

The aim of this study is to investigate a turbulent channel flow of compressible fluid numerically. The numerical method is finite difference method. LES(Large Eddy Simulation) method is adopted to display turbulent stress term and an approximation Roe scheme is used to solve an inviscid term. Besides, the preconditioning method is added to improve convergence speed of iteration procedure and cause accurate results to be obtained in all speed ranges. The results of Reynolds stresses , average velocity and vorticities of the flow field are examined and validated with existing paper.