关于两方程湍流模型的考虑

通过对两方程湍流模型的分析,提出了在主流区或远壁区用两方程模型,近壁区用代数湍流模型的思路,即所谓的“双层”模型概念。通过对平板湍流附面层的计算表明,这种分层计算措施获得的速度分布、壁面剪切力较单纯应用低雷诺数两方程湍流模型时的结果准确。对非均匀来流条件下90°弯管内高湍流度流场的计算表明,双层模型可获得更加准确的速度分布。从而表明本文提出的分层计算措施是有效的,可满足工程计算要求。 

A CONSIDERATION OF TWO EQUATION TURBULENCE MODEL

A concept of "two-layer" turbulence model is proposed which employs an algebraic turbulence model in near wall area and a two-equation turbulence model in outer area or far wall area.The flows over a flat plate with M =0 3 uniform inflow and in a 90°rectangular bent duct with non-uniform velocity and high turbulence inflow are calculated respectively by use of the "two layer" turbulence model and two equation turbulence model with low Reynolds number modification.The obtained results show that the "two layer" turbulence model can predict the distribution of velocity and wall stress for external flow and the boundary layer thickness and main velocity for internal flow more accurately than the two equation turbulence model.Therefore the "two layer" model is a powerful tool in engineering.