标准的与非线性的k-ε模型在二维剪切流中的应用

 采用标准 k-ε和非线性 k-ε模型对二维直通道及小曲率弯道中的剪切流进行了数值计算。与实验结果对比后得到 :由于非线性 k-ε模型考虑了流体变形与应力关系中的非线性项,因而能正确地反映湍流各向异性,能正确预测二维剪切流中湍流强度及湍流动能等参数的分布

COMPARISON OF NUMERICAL SIMULATION IN 2D SHEAR FLOWS WITH NONLINEAR AND STANDARD k-ε MODELS OF TURBULENCE

As compared with a standard k ε turbulent model,the nonlinear model contains nonlinear terms of deformation rates in the relationship between stress and deformation of the fluid,which conforms more closely to the objective laws of stress deformation,especially under the condition of large deformation.Therefore,it might predict the distribution of the Reynolds stresses and turbulent intensity accurately.This judgement was proved by numerical simulations of two dimensional turbulent shear flows in the straight as well as small curvature channels with both models.The calculated results are compared with experimental data.It shows that the nonlinear k ε model can predict the anisotropy of the turbulence accurately,which may be used extensively by engineers in the future.