用一种非线性k-ε模型计算突扩台阶后的流动

COMPUTATION OF TURBULENT FLOW PASSING A BACKWARD-FACING STEP WITH A NONLINEAR κ-ε MODEL

关键词:  管道流  紊流  流场  计算

Key words:  Channel flow  Turbulent flow  Flow field  Computation

摘要:

对一种新的非线性k-ε模型的无量纲系数进行了重新拟合.用新的系数计算了槽道流动、方截面管流和等应变率,平均流场无旋流动的正应力分布.计算结果与实验资料符合很好.将该模型并入常规的k-ε模型的计算程序中,并对突扩台阶后的湍流流动进行了数值计算,同线性k-ε模型的计算结果和实验结果进行了比较.结果表明,这种非线性k-ε模型同线性模型相比有较大的改进,同已有的其它非线性模型相比,也有一定的优点.

Abstract:

The model coefficients in a new nonlinear k-ε turbulence model have been revised.With this new model and the new coefficients, the Reynolds stresses in channel flow, square duct flow and flow with constant rate of strain are calculated. They are consistent well with the experimental data. Numerical solution of turbulent flow passing a backward-facing step with this model has been obtained,Comparison are made between the results predicted by this new nonlinear model and those obtained from the linear k-ε model as well as the experimental data.The result shows that this model have a great improvement upon the linear k-ε model.It also has advantages over other nonlinear k-ε models.