一种基于湍动能方程的转捩判定方法简

转捩现象是阻碍阻力高精度求解的主要问题之一. Menter 和Langtry 所提出的γ-θ转捩模型通过引入涡量雷诺数和间歇因子输运方程来驱动转捩，但是其中很多经验公式的理论立足点有待商榷. 驱使层流转变到湍流依赖的仍然是平均速度的一阶和二阶相关量，它们组合构成了湍动能方程的耗散尺度. 在湍动能方程中做合适的耗散平衡后，仅仅依靠湍动能方程可以有效地捕捉转捩现象. 采用自然转捩和旁路转捩测试算例进行了验证，结果证明该方法与试验值匹配较好，具有一定的工程实用价值.

A TRANSITION PREDICTION METHOD BASED ON TURBULENCE KINETIC EQUATION

Transition is a chief obstacle for high-accuracy prediction of drag. The γ-θ transition model proposed by Menter and Langtry increases the adaptability by inducing vorticity Reynolds number and intermittency factor, but there are lots of empirical formulae that cannot be told the lodgments of theory. The dissipation term of kinetic energy can be sufficiently constructed with the first and second order correlations of velocity. Transition phenomena can be caught by adding some dissipation terms into the turbulent kinetic energy equation. The method is tested by a natural transition and two bypass transition test cases. The results approve that this method can be applied in engineering turbulence flows simulation.