Abstract: 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.

Key words: k-E turbulence model, shear flow, nonlinearity