入口速度分布对后台阶流动模拟的影响研究

Study of Influence on Velocity Distribution of Backward-Facing Step Flow by Inlet Velocity Condition

为深入研究台阶入口速度分布情况对后台阶流动的影响,利用Fluent软件,分别使用S-A和标准κ-ε两种湍流模型,将不同的速度分布情况作为速度入口条件,对后台阶流动进行数值仿真计算,研究了入口条件差异导致的水平速度曲线在近壁面处的凸起情况,并将计算结果与试验数据和已有研究成果进行比较。结果表明,两种湍流模式下,在附着点距离和速度分布曲线上均存在普遍而明显的差异,且这种差异受入口条件影响较大,进而得出了合理的速度入口条件,能有效减小计算结果与试验结果的误差,对理论分析和工程应用均具有参考意义。

In order to study the influence of the inlet velocity distribution on the backward-facing step flow, with the use of FLUENT software, simulations are carried out to study the backward facing step flow under different inlet velocity conditions. S-A model and standard k-ε model are the turbulence models used in this study. This paper studies the small peak near the wall of velocity curves and compares the simulations results with the experimental data. It is found that the results have normal and obvious differences on the reattachment lengths and velocity distributions in backward-facing step flow, which are greatly influenced by inlet velocity conditions. In addition, the more valid inlet velocity conditions are giv- en in this paper. It can reduce the errors between calculations and experiments, which have reference values in theory analysis and engineering applications.